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Chu YZ, Hoover M, Ward P, Lau KC. First-principles study of MXene properties with varying hydrofluoric acid concentration. iScience 2024; 27:108784. [PMID: 38292429 PMCID: PMC10826293 DOI: 10.1016/j.isci.2024.108784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 08/30/2023] [Accepted: 01/02/2024] [Indexed: 02/01/2024] Open
Abstract
With varying hydrofluoric acid (HF) concentrations under three etching conditions, we presented a comparative study of the effects of both the ordered and randomly ternary mixed terminated Ti3C2Tx surfaces with a wide variation of O/OH/F stoichiometry on the thermodynamic stability and electronic properties. Regardless of the HF concentration, an OH-rich surface is found to be thermodynamically stable and the electrical conductivity of Ti3C2Tx is substantially affected by the OH concentration. The charge density difference and electron localization function demonstrated a significant electron localization at the hydroxyl group on the O/OH/F mixed terminated surface, which could yield a locally induced dipole on the surface that renders favorable reaction sites on the functionalized surface. In addition, a large tunability in the work function (ΔΦ ∼ 3.5 eV) is predicted for Ti3C2Tx. These findings provide a pathway for strategically tuning the electronic and structural properties of Ti3C2 MXenes etched with HF.
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Affiliation(s)
- Yi Zhi Chu
- Department of Physics, Michigan Technological University, Houghton, MI 49931, USA
- Department of Physics and Astronomy, California State University, Northridge, CA 91330, USA
| | - Megan Hoover
- Advanced Modeling and Simulations, Savannah River National Laboratory, Aiken, SC 29803, USA
| | - Patrick Ward
- Materials Technology and Energy Division, Savannah River National Laboratory, Aiken, SC 29803, USA
| | - Kah Chun Lau
- Department of Physics and Astronomy, California State University, Northridge, CA 91330, USA
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Wang HH, Zhang C, Gao J, Lau KC, Plunkett ST, Park M, Amine R, Curtiss LA. Template assisted lithium superoxide growth for lithium-oxygen batteries. Faraday Discuss 2024; 248:48-59. [PMID: 37791512 DOI: 10.1039/d3fd00116d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
Developing batteries with energy densities comparable to internal combustion technology is essential for a worldwide transition to electrified transportation. Li-O2 batteries are seen as the 'holy grail' of battery technologies since they have the highest theoretical energy density of all battery technologies. Current lithium-oxygen (Li-O2) batteries suffer from large charge overpotentials related to the electronic resistivity of the insulating lithium peroxide (Li2O2) discharge product. One potential solution is the formation and stabilization of a lithium superoxide (LiO2) discharge intermediate that exhibits good electronic conductivity. However, LiO2 is reported to be unstable at ambient temperature despite its favorable formation energy at -1.0 eV per atom. In this paper - based on our recent work on the development of cathode materials for aprotic lithium oxygen batteries including two intermetallic compounds, LiIr3 and LiIr, that are found to form good template interfaces with LiO2 - a simple goodness of fit R factor to gauge how well a template surface structure can support LiO2 growth, is developed. The R factor is a quantitative measurement to calculate the geometric difference in the unit cells of specific Miller Index 2D planes of the template surface and LiO2. Using this as a guide, the R factors for LiIr3, LiIr, and La2NiO4+δ, are found to be good. This guide is attested by simple extension to other noble metal intermetallics with electrochemical cycling data including LiRh3, LiRh, and Li2Pd. Finally, the template concept is extended to main group elements and the R factors for LiO2 (111) and Li2Ca suggest that Li2Ca is a possible candidate for the template assisted LiO2 growth strategy.
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Affiliation(s)
- Hsien-Hau Wang
- Materials Science Division, Argonne National Laboratory, Lemont, IL, USA.
| | - Chengji Zhang
- Materials Science Division, Argonne National Laboratory, Lemont, IL, USA.
- Department of Chemical Engineering, University of Illinois at Chicago, Chicago, IL, USA
| | - Jing Gao
- Materials Science Division, Argonne National Laboratory, Lemont, IL, USA.
- Department of Chemical Engineering, University of Illinois at Chicago, Chicago, IL, USA
| | - Kah Chun Lau
- Materials Science Division, Argonne National Laboratory, Lemont, IL, USA.
- Department of Physics and Astronomy, California State University, Northridge, CA, USA
| | - Samuel T Plunkett
- Materials Science Division, Argonne National Laboratory, Lemont, IL, USA.
- Department of Chemical Engineering, University of Illinois at Chicago, Chicago, IL, USA
| | - Moon Park
- Materials Science Division, Argonne National Laboratory, Lemont, IL, USA.
| | - Rachid Amine
- Materials Science Division, Argonne National Laboratory, Lemont, IL, USA.
| | - Larry A Curtiss
- Materials Science Division, Argonne National Laboratory, Lemont, IL, USA.
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3
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Co M, Cheng KCK, Yeung YH, Lau KC, Qian Z, Wong CM, Wong BY, Sin ELK, Wong HYS, Ma CH. Clinical Outcomes of Conservative Treatment for Low-Risk Ductal Carcinoma in Situ: A Systematic Review and Pooled Analysis. Clin Oncol (R Coll Radiol) 2023; 35:255-261. [PMID: 36764879 DOI: 10.1016/j.clon.2023.01.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 12/05/2022] [Accepted: 01/26/2023] [Indexed: 02/04/2023]
Abstract
AIMS The current gold standard of treatment for ductal carcinoma in situ (DCIS) is surgical resection with or without adjuvant radiotherapy. However, the increased detection and radical treatment of DCIS did not result in a declined incidence of invasive breast cancers, leading to the debate if DCIS has been overtreated. While ongoing randomised controlled trials on active surveillance of DCIS are still in progress, this systematic review aims to evaluate the best evidence on conservative treatment for DCIS from the literature. MATERIALS AND METHODS This systematic review was conducted in line with the PRISMA statement. We included all relevant studies published up to June 2022 for analysis. The primary outcomes were overall survival and breast cancer-specific survival (BCSS) of conservative treatment for DCIS. RESULTS Three studies, with a total of 34 007 women with low-risk DCIS, were included in the analysis. Active and conservative treatments both resulted in excellent 10-year BCSS, with no statistically insignificant difference (98.6% versus 96.0%, 31 478 women). One study comparing 5-year BCSS of active and conservative treatments only in subjects aged over 80 years also reported [AQ1]an insignificant difference (98.2% versus 96.0%, 2529 women). One study measuring 5- and 10-year overall survival between the treatment groups also reported [AQ1]an insignificant difference (5-year: 96.2% versus 92.4%; 10-year: 85.6% versus 86.7%, 31 106 women). CONCLUSION BCSS between active and conservative treatment for women with low-risk DCIS is both excellent and comparable, suggesting that conservative treatment is a possible alternative without compromising survival.
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Affiliation(s)
- M Co
- Center for Education and Training, Department of Surgery, University of Hong Kong, Hong Kong; Division of Breast Surgery, Queen Mary Hospital, Hong Kong.
| | - K C K Cheng
- Center for Education and Training, Department of Surgery, University of Hong Kong, Hong Kong
| | - Y H Yeung
- Center for Education and Training, Department of Surgery, University of Hong Kong, Hong Kong
| | - K C Lau
- Center for Education and Training, Department of Surgery, University of Hong Kong, Hong Kong
| | - Z Qian
- Center for Education and Training, Department of Surgery, University of Hong Kong, Hong Kong
| | - C M Wong
- Center for Education and Training, Department of Surgery, University of Hong Kong, Hong Kong
| | - B Y Wong
- Center for Education and Training, Department of Surgery, University of Hong Kong, Hong Kong
| | - E L K Sin
- Center for Education and Training, Department of Surgery, University of Hong Kong, Hong Kong
| | - H Y S Wong
- Center for Education and Training, Department of Surgery, University of Hong Kong, Hong Kong
| | - C H Ma
- Center for Education and Training, Department of Surgery, University of Hong Kong, Hong Kong
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Schkeryantz L, Nguyen P, McCulloch WD, Moore CE, Lau KC, Wu Y. Unusual Melting Trend in an Alkali Asymmetric Sulfonamide Salt Series: Single-Crystal Analysis and Modeling. Inorg Chem 2021; 60:14679-14686. [PMID: 34555283 DOI: 10.1021/acs.inorgchem.1c01752] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Developing low-melting alkali salts is of interest for both battery electrolytes and inorganic ionic liquids. In this study, we report a series of asymmetric alkali-metal sulfonamide salts based upon the (3-methoxypropyl)((trifluoromethyl)sulfonyl)amide (MPSA) anion. This family of salts features an unusual melting point trend, where the melting point of the salts decreases as the cation increases in size from Li to K but then the melting point increases as the cation further increases in size from K to Cs. Analyses of single crystals reveal that the unusual higher melting points of RbMPSA and CsMPSA in comparison to KMPSA can be attributed to the greater cation-cation distances as well as the increased rigidity of anion-cation coordination due to an increase in cyclic structures in comparison to KMPSA. Exceptionally, KMPSA features a very low melting point of only 50.79 ± 0.31 °C. This low melting point can be attributed to a relatively high degree of disorder, an unusual uncoordinated ether moiety, and a very short K-K distance of only 3.4348(7) Å among other factors, which is supported by the low cohesive energy and small elastic moduli among the rest according to density functional theory (DFT) calculations. The low melting point of KMPSA makes it interesting for low-temperature ionic liquids.
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Affiliation(s)
- Luke Schkeryantz
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, United States
| | - Phu Nguyen
- Department of Physics and Astronomy, California State University, Northridge, California 91330, United States
| | - William D McCulloch
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, United States
| | - Curtis E Moore
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, United States
| | - Kah Chun Lau
- Department of Physics and Astronomy, California State University, Northridge, California 91330, United States
| | - Yiying Wu
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, United States
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Halder A, Ngo AT, Luo X, Wang HH, Wen JG, Abbasi P, Asadi M, Zhang C, Miller D, Zhang D, Lu J, Redfern PC, Lau KC, Amine R, Assary RS, Lee YJ, Salehi-Khojin A, Vajda S, Amine K, Curtiss LA. In Situ Formed Ir3Li Nanoparticles as Active Cathode Material in Li–Oxygen Batteries. J Phys Chem A 2019; 123:10047-10056. [DOI: 10.1021/acs.jpca.9b06875] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Avik Halder
- Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Anh T. Ngo
- Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Xiangyi Luo
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Hsien-Hau Wang
- Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - J. G. Wen
- Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Pedram Abbasi
- Department of Mechanical and Industrial, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Mohammad Asadi
- Department of Mechanical and Industrial, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Chengji Zhang
- Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
- Department of Civil and Materials Engineering, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Dean Miller
- Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Dongzhou Zhang
- Partnership for Extreme Crystallography, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Jun Lu
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Paul C. Redfern
- Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Kah Chun Lau
- Department of Physics and Astronomy, California State University, Northridge, California 91330, United States
| | - Rachid Amine
- Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
- Department of Chemical Engineering, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Rajeev S. Assary
- Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Yun Jung Lee
- Department of Engineering, Hanyang University, Seoul 133-791, Republic of Korea
| | - Amin Salehi-Khojin
- Department of Mechanical and Industrial, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Stefan Vajda
- Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
- Institute for Molecular Engineering, The University of Chicago, Chicago, Illinois 60637, United States
- Department of Nanocatalysis, J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Dolejškova 3, 18223 Prague 8, Czech Republic
| | - Khalil Amine
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
- Department of Material Science and Engineering, Stanford University, 450 Serra Mall, Stanford, California 94305, United States
- Institute for Research and Medical Consultations (IRMC), Imam Abdulrahman Bin Faisal University (IAU), Dammam 34212, Saudi Arabia
| | - Larry A. Curtiss
- Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
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Li Y, Romero NA, Lau KC. Structure-Property of Lithium-Sulfur Nanoparticles via Molecular Dynamics Simulation. ACS Appl Mater Interfaces 2018; 10:37575-37585. [PMID: 30298723 DOI: 10.1021/acsami.8b09128] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Lithium-sulfur (Li-S) batteries offer higher energy densities than most reported lithium-ion batteries. However, our understanding of Li-S battery is still largely unknown at the level of the nanoscale. The structural properties of Li-S materials were investigated via molecular dynamics (MD) simulations using the ReaxFF force field. Several Li-S nanoparticles with different Li/S composition ratios (2:1 and 2:8) and various structures are studied. Our MD simulations show that among the four structures we constructed for Li2S8 nanoparticles, the core-shell structure is the most thermodynamically stable one during the charging (delithiation) process. In contrast to bulk crystal Li2S, we find the presence of mixed lithium sulfide and polysulfide species are common features for these Li-S (Li2S, Li2S8) nanoparticles. The complex distribution of these sulfide and polysulfide speciation are dictated by both stoichiometry and local atomic structures in the nanoparticle. These findings will provide insight into further development of functionalized lithium-sulfur cathodes.
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Affiliation(s)
| | | | - Kah Chun Lau
- Department of Physics & Astronomy , California State University, Northridge , Northridge , California 91330 , United States
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7
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Yu W, Lau KC, Lei Y, Liu R, Qin L, Yang W, Li B, Curtiss LA, Zhai D, Kang F. Dendrite-Free Potassium-Oxygen Battery Based on a Liquid Alloy Anode. ACS Appl Mater Interfaces 2017; 9:31871-31878. [PMID: 28849647 DOI: 10.1021/acsami.7b08962] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The safety issue caused by the dendrite growth is not only a key research problem in lithium-ion batteries but also a critical concern in alkali metal (i.e., Li, Na, and K)-oxygen batteries where a solid metal is usually used as the anode. Herein, we demonstrate the first dendrite-free K-O2 battery at ambient temperature based on a liquid Na-K alloy anode. The unique liquid-liquid connection between the liquid alloy and the electrolyte in our alloy anode-based battery provides a homogeneous and robust anode-electrolyte interface. Meanwhile, we manage to show that the Na-K alloy is only compatible in K-O2 batteries but not in Na-O2 batteries, which is mainly attributed to the stronger reducibility of potassium and relatively more favorable thermodynamic formation of KO2 over NaO2 during the discharge process. It is observed that our K-O2 battery based on a liquid alloy anode shows a long cycle life (over 620 h) and a low discharge-charge overpotential (about 0.05 V at initial cycles). Moreover, the mechanism investigation into the K-O2 cell degradation shows that the O2 crossover effect and the ether-electrolyte instability are the critical problems for K-O2 batteries. In a word, this study provides a new route to solve the problems caused by the dendrite growth in alkali metal-oxygen batteries.
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Affiliation(s)
- Wei Yu
- Advanced Materials Institute, Graduate School at Shenzhen, Tsinghua University , Shenzhen 518055, China
- School of Materials Science and Engineering, Tsinghua University , Beijing 100084, China
| | - Kah Chun Lau
- Department of Physics and Astronomy, California State University Northridge , 18111 Nordhoff Street, Northridge, California 91330-8268, United States
| | - Yu Lei
- Advanced Materials Institute, Graduate School at Shenzhen, Tsinghua University , Shenzhen 518055, China
| | - Ruliang Liu
- Materials Science Institute, PCFM Lab and GDHPPC Lab, School of Chemistry, Sun Yat-sen University , Guangzhou 510275, China
| | - Lei Qin
- Advanced Materials Institute, Graduate School at Shenzhen, Tsinghua University , Shenzhen 518055, China
- School of Materials Science and Engineering, Tsinghua University , Beijing 100084, China
| | - Wei Yang
- Advanced Materials Institute, Graduate School at Shenzhen, Tsinghua University , Shenzhen 518055, China
| | - Baohua Li
- Advanced Materials Institute, Graduate School at Shenzhen, Tsinghua University , Shenzhen 518055, China
| | - Larry A Curtiss
- Materials Science Division, Argonne National Laboratory , Argonne, Illinois 60439, United States
| | - Dengyun Zhai
- Advanced Materials Institute, Graduate School at Shenzhen, Tsinghua University , Shenzhen 518055, China
| | - Feiyu Kang
- Advanced Materials Institute, Graduate School at Shenzhen, Tsinghua University , Shenzhen 518055, China
- School of Materials Science and Engineering, Tsinghua University , Beijing 100084, China
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8
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See KA, Wu HL, Lau KC, Shin M, Cheng L, Balasubramanian M, Gallagher KG, Curtiss LA, Gewirth AA. Effect of Hydrofluoroether Cosolvent Addition on Li Solvation in Acetonitrile-Based Solvate Electrolytes and Its Influence on S Reduction in a Li-S Battery. ACS Appl Mater Interfaces 2016; 8:34360-34371. [PMID: 27998132 DOI: 10.1021/acsami.6b11358] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Li-S batteries are a promising next-generation battery technology. Due to the formation of soluble polysulfides during cell operation, the electrolyte composition of the cell plays an active role in directing the formation and speciation of the soluble lithium polysulfides. Recently, new classes of electrolytes termed "solvates" that contain stoichiometric quantities of salt and solvent and form a liquid at room temperature have been explored due to their sparingly solvating properties with respect to polysulfides. The viscosity of the solvate electrolytes is understandably high limiting their viability; however, hydrofluoroether cosolvents, thought to be inert to the solvate structure itself, can be introduced to reduce viscosity and enhance diffusion. Nazar and co-workers previously reported that addition of 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether (TTE) to the LiTFSI in acetonitrile solvate, (MeCN)2-LiTFSI, results in enhanced capacity retention compared to the neat solvate. Here, we evaluate the effect of TTE addition on both the electrochemical behavior of the Li-S cell and the solvation structure of the (MeCN)2-LiTFSI electrolyte. Contrary to previous suggestions, Raman and NMR spectroscopy coupled with ab initio molecular dynamics simulations show that TTE coordinates to Li+ at the expense of MeCN coordination, thereby producing a higher content of free MeCN, a good polysulfide solvent, in the electrolyte. The electrolytes containing a higher free MeCN content facilitate faster polysulfide formation kinetics during the electrochemical reduction of S in a Li-S cell likely as a result of the solvation power of the free MeCN.
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Affiliation(s)
- Kimberly A See
- Joint Center for Energy Storage Research , 9700 South Cass Avenue, Argonne, Illinois 60439, United States
- Department of Chemistry, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
| | - Heng-Liang Wu
- Joint Center for Energy Storage Research , 9700 South Cass Avenue, Argonne, Illinois 60439, United States
- Department of Chemistry, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
| | - Kah Chun Lau
- Joint Center for Energy Storage Research , 9700 South Cass Avenue, Argonne, Illinois 60439, United States
- Department of Physics and Astronomy, California State University , Northridge, California 91330, United States
| | - Minjeong Shin
- Joint Center for Energy Storage Research , 9700 South Cass Avenue, Argonne, Illinois 60439, United States
- Department of Chemistry, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
| | - Lei Cheng
- Joint Center for Energy Storage Research , 9700 South Cass Avenue, Argonne, Illinois 60439, United States
| | - Mahalingam Balasubramanian
- Joint Center for Energy Storage Research , 9700 South Cass Avenue, Argonne, Illinois 60439, United States
| | - Kevin G Gallagher
- Joint Center for Energy Storage Research , 9700 South Cass Avenue, Argonne, Illinois 60439, United States
| | - Larry A Curtiss
- Joint Center for Energy Storage Research , 9700 South Cass Avenue, Argonne, Illinois 60439, United States
| | - Andrew A Gewirth
- Joint Center for Energy Storage Research , 9700 South Cass Avenue, Argonne, Illinois 60439, United States
- Department of Chemistry, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
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9
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He M, Lau KC, Ren X, Xiao N, McCulloch WD, Curtiss LA, Wu Y. Concentrated Electrolyte for the Sodium-Oxygen Battery: Solvation Structure and Improved Cycle Life. Angew Chem Int Ed Engl 2016; 55:15310-15314. [PMID: 27809386 DOI: 10.1002/anie.201608607] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 10/03/2016] [Indexed: 11/09/2022]
Affiliation(s)
- Mingfu He
- Department of Chemistry & Biochemistry; The Ohio State University; 100 West 18th Avenue Columbus OH 43210 USA
| | - Kah Chun Lau
- Department of Physics and Astronomy; California State University; 18111 Nordhoff Street Northridge CA 91330 USA
| | - Xiaodi Ren
- Department of Chemistry & Biochemistry; The Ohio State University; 100 West 18th Avenue Columbus OH 43210 USA
| | - Neng Xiao
- Department of Chemistry & Biochemistry; The Ohio State University; 100 West 18th Avenue Columbus OH 43210 USA
| | - William D. McCulloch
- Department of Chemistry & Biochemistry; The Ohio State University; 100 West 18th Avenue Columbus OH 43210 USA
| | - Larry A. Curtiss
- Materials Science Division; Argonne National Laboratory; 9700 S. Cass Avenue Lemont IL 60439 USA
| | - Yiying Wu
- Department of Chemistry & Biochemistry; The Ohio State University; 100 West 18th Avenue Columbus OH 43210 USA
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10
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He M, Lau KC, Ren X, Xiao N, McCulloch WD, Curtiss LA, Wu Y. Concentrated Electrolyte for the Sodium-Oxygen Battery: Solvation Structure and Improved Cycle Life. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201608607] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Mingfu He
- Department of Chemistry & Biochemistry; The Ohio State University; 100 West 18th Avenue Columbus OH 43210 USA
| | - Kah Chun Lau
- Department of Physics and Astronomy; California State University; 18111 Nordhoff Street Northridge CA 91330 USA
| | - Xiaodi Ren
- Department of Chemistry & Biochemistry; The Ohio State University; 100 West 18th Avenue Columbus OH 43210 USA
| | - Neng Xiao
- Department of Chemistry & Biochemistry; The Ohio State University; 100 West 18th Avenue Columbus OH 43210 USA
| | - William D. McCulloch
- Department of Chemistry & Biochemistry; The Ohio State University; 100 West 18th Avenue Columbus OH 43210 USA
| | - Larry A. Curtiss
- Materials Science Division; Argonne National Laboratory; 9700 S. Cass Avenue Lemont IL 60439 USA
| | - Yiying Wu
- Department of Chemistry & Biochemistry; The Ohio State University; 100 West 18th Avenue Columbus OH 43210 USA
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11
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Bellili A, Pan Y, Al Mogren MM, Lau KC, Hochlaf M. Electronic, structural and vibrational induced effects upon ionization of 2-quinolinone. Spectrochim Acta A Mol Biomol Spectrosc 2016; 164:1-7. [PMID: 27060413 DOI: 10.1016/j.saa.2016.03.043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 03/22/2016] [Accepted: 03/27/2016] [Indexed: 06/05/2023]
Abstract
Using first principle methodologies, we characterize the lowest electronic states of 2-quinolinone(+) cation. The ground state of this ion is of X˜(2)A(″) nature. We deduce the adiabatic ionization energy of 2-quinolinone to be equal 8.249eV using the explicitly correlated coupled cluster level and where zero point vibrational energy, core-valence and scalar relativistic effects are taken into account. We examine also the ionization induced structural changes and vibrational shifts and analyze the electron density differences between the neutral and ionic species. These data show that the formation of 2-quinolinone(+)X˜(2)A(″) from 2-quinolinone affects strongly the HNCO group, whereas the carbon skeletal is perturbed when the upper electronic cationic states are populated. The comparison to 2-pyridone allows the elucidation of the effect of benzene ring fused with this heterocyclic ring. Since quinolones and pyridones are both model systems of DNA bases, these findings might help in understanding the charge redistribution in these biological entities upon ionization.
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Affiliation(s)
- A Bellili
- Université Paris-Est, Laboratoire Modélisation et Simulation Multi Echelle, MSME UMR 8208 CNRS, 5 bd Descartes, 77454 Marne-la-Vallée, France
| | - Y Pan
- Department of Biology and Chemistry, City University of Hong Kong, Kowloon, Hong Kong
| | - M M Al Mogren
- Chemistry Department, Faculty of Science, King Saud University, PO Box 2455, Riyadh 11451, Saudi Arabia
| | - K C Lau
- Department of Biology and Chemistry, City University of Hong Kong, Kowloon, Hong Kong.
| | - M Hochlaf
- Université Paris-Est, Laboratoire Modélisation et Simulation Multi Echelle, MSME UMR 8208 CNRS, 5 bd Descartes, 77454 Marne-la-Vallée, France.
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12
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Welland MJ, Lau KC, Redfern PC, Liang L, Zhai D, Wolf D, Curtiss LA. An atomistically informed mesoscale model for growth and coarsening during discharge in lithium-oxygen batteries. J Chem Phys 2016; 143:224113. [PMID: 26671364 DOI: 10.1063/1.4936410] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
An atomistically informed mesoscale model is developed for the deposition of a discharge product in a Li-O2 battery. This mescocale model includes particle growth and coarsening as well as a simplified nucleation model. The model involves LiO2 formation through reaction of O2(-) and Li(+) in the electrolyte, which deposits on the cathode surface when the LiO2 concentration reaches supersaturation in the electrolyte. A reaction-diffusion (rate-equation) model is used to describe the processes occurring in the electrolyte and a phase-field model is used to capture microstructural evolution. This model predicts that coarsening, in which large particles grow and small ones disappear, has a substantial effect on the size distribution of the LiO2 particles during the discharge process. The size evolution during discharge is the result of the interplay between this coarsening process and particle growth. The growth through continued deposition of LiO2 has the effect of causing large particles to grow ever faster while delaying the dissolution of small particles. The predicted size evolution is consistent with experimental results for a previously reported cathode material based on activated carbon during discharge and when it is at rest, although kinetic factors need to be included. The approach described in this paper synergistically combines models on different length scales with experimental observations and should have applications in studying other related discharge processes, such as Li2O2 deposition, in Li-O2 batteries and nucleation and growth in Li-S batteries.
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Affiliation(s)
- Michael J Welland
- Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Kah Chun Lau
- Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Paul C Redfern
- Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Linyun Liang
- Mathematics and Computer Science, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Denyun Zhai
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Dieter Wolf
- Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Larry A Curtiss
- Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
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Lu J, Jung Lee Y, Luo X, Chun Lau K, Asadi M, Wang HH, Brombosz S, Wen J, Zhai D, Chen Z, Miller DJ, Sub Jeong Y, Park JB, Zak Fang Z, Kumar B, Salehi-Khojin A, Sun YK, Curtiss LA, Amine K. A lithium–oxygen battery based on lithium superoxide. Nature 2016; 529:377-82. [DOI: 10.1038/nature16484] [Citation(s) in RCA: 537] [Impact Index Per Article: 67.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Accepted: 11/13/2015] [Indexed: 12/24/2022]
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Gyulassy A, Knoll A, Lau KC, Wang B, Bremer PT, Papka ME, Curtiss LA, Pascucci V. Interstitial and Interlayer Ion Diffusion Geometry Extraction in Graphitic Nanosphere Battery Materials. IEEE Trans Vis Comput Graph 2016; 22:916-925. [PMID: 26529736 DOI: 10.1109/tvcg.2015.2467432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Large-scale molecular dynamics (MD) simulations are commonly used for simulating the synthesis and ion diffusion of battery materials. A good battery anode material is determined by its capacity to store ion or other diffusers. However, modeling of ion diffusion dynamics and transport properties at large length and long time scales would be impossible with current MD codes. To analyze the fundamental properties of these materials, therefore, we turn to geometric and topological analysis of their structure. In this paper, we apply a novel technique inspired by discrete Morse theory to the Delaunay triangulation of the simulated geometry of a thermally annealed carbon nanosphere. We utilize our computed structures to drive further geometric analysis to extract the interstitial diffusion structure as a single mesh. Our results provide a new approach to analyze the geometry of the simulated carbon nanosphere, and new insights into the role of carbon defect size and distribution in determining the charge capacity and charge dynamics of these carbon based battery materials.
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Zhai D, Lau KC, Wang HH, Wen J, Miller DJ, Kang F, Li B, Zavadil K, Curtiss LA. The Effect of Potassium Impurities Deliberately Introduced into Activated Carbon Cathodes on the Performance of Lithium-Oxygen Batteries. ChemSusChem 2015; 8:4235-4241. [PMID: 26630086 DOI: 10.1002/cssc.201500960] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Revised: 09/06/2015] [Indexed: 06/05/2023]
Abstract
Rechargeable lithium-air (Li-O2) batteries have drawn much interest owing to their high energy density. We report on the effect of deliberately introducing potassium impurities into the cathode material on the electrochemical performance of a Li-O2 battery. Small amounts of potassium introduced into the activated carbon (AC) cathode material in the synthesis process are found to have a dramatic effect on the performance of the Li-O2 cell. An increased amount of potassium significantly increases capacity, cycle life, and round-trip efficiency. This improved performance is probably due to a larger amount of LiO2 in the discharge product, which is a mixture of LiO2 and Li2O2, resulting from the increase in the amount of potassium present. No substantial correlation with porosity or surface area in an AC cathode is found. Experimental and computational studies indicate that potassium can act as an oxygen reduction catalyst, which can account for the dependence of performance on the amount of potassium.
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Affiliation(s)
- Dengyun Zhai
- Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL, 60439, USA
| | - Kah Chun Lau
- Materials Science Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL, 60439, USA
| | - Hsien-Hau Wang
- Materials Science Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL, 60439, USA
| | - Jianguo Wen
- Electron Microscopy Center, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL, 60439, USA
| | - Dean J Miller
- Electron Microscopy Center, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL, 60439, USA
| | - Feiyu Kang
- Graduate School at Shenzhen, Tsinghua University, The University Town, Shenzhen, 518055, PR China
| | - Baohua Li
- Graduate School at Shenzhen, Tsinghua University, The University Town, Shenzhen, 518055, PR China
| | - Kevin Zavadil
- Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, NM, 87185, USA
| | - Larry A Curtiss
- Materials Science Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL, 60439, USA.
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Kwak WJ, Lau KC, Shin CD, Amine K, Curtiss LA, Sun YK. A Mo2C/Carbon Nanotube Composite Cathode for Lithium-Oxygen Batteries with High Energy Efficiency and Long Cycle Life. ACS Nano 2015; 9:4129-4137. [PMID: 25801846 DOI: 10.1021/acsnano.5b00267] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Although lithium-oxygen batteries are attracting considerable attention because of the potential for an extremely high energy density, their practical use has been restricted owing to a low energy efficiency and poor cycle life compared to lithium-ion batteries. Here we present a nanostructured cathode based on molybdenum carbide nanoparticles (Mo2C) dispersed on carbon nanotubes, which dramatically increase the electrical efficiency up to 88% with a cycle life of more than 100 cycles. We found that the Mo2C nanoparticle catalysts contribute to the formation of well-dispersed lithium peroxide nanolayers (Li2O2) on the Mo2C/carbon nanotubes with a large contact area during the oxygen reduction reaction (ORR). This Li2O2 structure can be decomposed at low potential upon the oxygen evolution reaction (OER) by avoiding the energy loss associated with the decomposition of the typical Li2O2 discharge products.
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Affiliation(s)
- Won-Jin Kwak
- †Department of Energy Engineering, Hanyang University, Seoul, 133-791, Republic of Korea
| | | | - Chang-Dae Shin
- †Department of Energy Engineering, Hanyang University, Seoul, 133-791, Republic of Korea
| | | | | | - Yang-Kook Sun
- †Department of Energy Engineering, Hanyang University, Seoul, 133-791, Republic of Korea
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Zhai D, Lau KC, Wang HH, Wen J, Miller DJ, Lu J, Kang F, Li B, Yang W, Gao J, Indacochea E, Curtiss LA, Amine K. Interfacial effects on lithium superoxide disproportionation in Li-O₂ batteries. Nano Lett 2015; 15:1041-1046. [PMID: 25615912 DOI: 10.1021/nl503943z] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
During the cycling of Li-O2 batteries the discharge process gives rise to dynamically evolving agglomerates composed of lithium-oxygen nanostructures; however, little is known about their composition. In this paper, we present results for a Li-O2 battery based on an activated carbon cathode that indicate interfacial effects can suppress disproportionation of a LiO2 component in the discharge product. High-intensity X-ray diffraction and transmission electron microscopy measurements are first used to show that there is a LiO2 component along with Li2O2 in the discharge product. The stability of the discharge product was then probed by investigating the dependence of the charge potential and Raman intensity of the superoxide peak with time. The results indicate that the LiO2 component can be stable for possibly up to days when an electrolyte is left on the surface of the discharged cathode. Density functional calculations on amorphous LiO2 reveal that the disproportionation process will be slower at an electrolyte/LiO2 interface compared to a vacuum/LiO2 interface. The combined experimental and theoretical results provide new insight into how interfacial effects can stabilize LiO2 and suggest that these interfacial effects may play an important role in the charge and discharge chemistries of a Li-O2 battery.
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Affiliation(s)
- Dengyun Zhai
- Chemical Sciences and Engineering Division, ‡Materials Science Division, and §Electron Microscopy Center, Argonne National Laboratory , Argonne, Illinois 60439, United States
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Lau KC, Lu J, Luo X, Curtiss LA, Amine K. Frontispiece: Implications of the Unpaired Spins in Li-O 2Battery Chemistry and Electrochemistry: A Minireview. Chempluschem 2015. [DOI: 10.1002/cplu.201580265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Ren X, Lau KC, Yu M, Bi X, Kreidler E, Curtiss LA, Wu Y. Understanding side reactions in K-O2 batteries for improved cycle life. ACS Appl Mater Interfaces 2014; 6:19299-307. [PMID: 25295518 DOI: 10.1021/am505351s] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Superoxide based metal-air (or metal-oxygen) batteries, including potassium and sodium-oxygen batteries, have emerged as promising alternative chemistries in the metal-air battery family because of much improved round-trip efficiencies (>90%). In order to improve the cycle life of these batteries, it is crucial to understand and control the side reactions between the electrodes and the electrolyte. For potassium-oxygen batteries using ether-based electrolytes, the side reactions on the potassium anode have been identified as the main cause of battery failure. The composition of the side products formed on the anode, including some reaction intermediates, have been identified and quantified. Combined experimental studies and density functional theory (DFT) calculations show the side reactions are likely driven by the interaction of potassium with ether molecules and the crossover of oxygen from the cathode. To inhibit these side reactions, the incorporation of a polymeric potassium ion selective membrane (Nafion-K(+)) as a battery separator is demonstrated that significantly improves the battery cycle life. The K-O2 battery with the Nafion-K(+) separator can be discharged and charged for more than 40 cycles without increases in charging overpotential.
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Affiliation(s)
- Xiaodi Ren
- Department of Chemistry and Biochemistry, The Ohio State University , 100 West 18th Avenue, Columbus, Ohio 43210, United States
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Lu J, Cheng L, Lau KC, Tyo E, Luo X, Wen J, Miller D, Assary RS, Wang HH, Redfern P, Wu H, Park JB, Sun YK, Vajda S, Amine K, Curtiss LA. Effect of the size-selective silver clusters on lithium peroxide morphology in lithium–oxygen batteries. Nat Commun 2014; 5:4895. [DOI: 10.1038/ncomms5895] [Citation(s) in RCA: 164] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Accepted: 07/31/2014] [Indexed: 12/23/2022] Open
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21
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Zhai D, Wang HH, Lau KC, Gao J, Redfern PC, Kang F, Li B, Indacochea E, Das U, Sun HH, Sun HJ, Amine K, Curtiss LA. Raman Evidence for Late Stage Disproportionation in a Li-O2 Battery. J Phys Chem Lett 2014; 5:2705-10. [PMID: 26277967 DOI: 10.1021/jz501323n] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Raman spectroscopy is used to characterize the composition of toroids formed in an aprotic Li-O2 cell based on an activated carbon cathode. The trends in the Raman data as a function of discharge current density and charging cutoff voltage provide evidence that the toroids are made up of outer LiO2-like and inner Li2O2 regions, consistent with a disproportionation reaction occurring in the solid phase. The LiO2-like component is found to be associated with a new Raman peak identified in the carbon stretching region at ∼1505 cm(-1), which appears only when the LiO2 peak at 1123 cm(-1) is present. The new peak is assigned to distortion of the graphitic ring stretching due to coupling with the LiO2-like component based on density functional calculations. These new results on the LiO2-like component from Raman spectroscopy provide evidence that a late stage disproportionation mechanism can occur during discharge and add new understanding to the complexities of possible processes occurring in Li-O2 batteries.
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Affiliation(s)
- Dengyun Zhai
- †Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Hsien-Hau Wang
- ‡Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Kah Chun Lau
- ‡Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Jing Gao
- ∥Department of Civil and Materials Engineering, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Paul C Redfern
- †Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Feiyu Kang
- §Engineering Laboratory for Next Generation Power and Energy Storage Batteries, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China
| | - Baohua Li
- §Engineering Laboratory for Next Generation Power and Energy Storage Batteries, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China
| | - Ernesto Indacochea
- ∥Department of Civil and Materials Engineering, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Ujjal Das
- ‡Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Ho-Hyun Sun
- ‡Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Ho-Jin Sun
- ‡Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Khalil Amine
- †Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Larry A Curtiss
- ‡Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
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Lau KC, Lu J, Luo X, Curtiss LA, Amine K. Implications of the Unpaired Spins in Li-O2Battery Chemistry and Electrochemistry: A Minireview. Chempluschem 2014. [DOI: 10.1002/cplu.201402053] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Abstract
The discharge mechanism of a Li-O2 battery involves lithium superoxide (LiO2) radicals. In this Letter, we have performed high-level quantum chemical calculations (G4MP2) to investigate the structure and stability of LiO2 clusters. The clusters have planar ring-shaped structures, high spins, and are thermodynamically more stable than LiO2 dimer. The computed energy barrier for disproportionation of the larger clusters is also significantly higher than the corresponding barrier in the LiO2 dimer (1.0 eV vs 0.5 eV). This means that disproportionation rate should be much slower if the reaction involves LiO2 clusters other than the dimer. As a result, the clusters may survive long enough to be incorporated into the growing discharge product. These results are discussed in terms of recent experimental studies of the electronic structure and morphology of the discharge products in Li-air batteries.
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Affiliation(s)
- Ujjal Das
- †Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Kah Chun Lau
- †Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Paul C Redfern
- ‡Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Larry A Curtiss
- †Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
- §Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439, United States
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Lu J, Lei Y, Lau KC, Luo X, Du P, Wen J, Assary RS, Das U, Miller D, Elam JW, Albishri HM, El-Hady DA, Sun YK, Curtiss LA, Amine K. Erratum: Corrigendum: A nanostructured cathode architecture for low charge overpotential in lithium-oxygen batteries. Nat Commun 2014. [DOI: 10.1038/ncomms4290] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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Zhai D, Wang HH, Yang J, Lau KC, Li K, Amine K, Curtiss LA. Disproportionation in Li–O2 Batteries Based on a Large Surface Area Carbon Cathode. J Am Chem Soc 2013; 135:15364-72. [DOI: 10.1021/ja403199d] [Citation(s) in RCA: 250] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Dengyun Zhai
- Chemical
Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Hsien-Hau Wang
- Materials
Science Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Junbing Yang
- Chemical
Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Kah Chun Lau
- Materials
Science Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Kaixi Li
- Key
Laboratory of Carbon Materials, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan, Shanxi 030001, PR China
| | - Khalil Amine
- Chemical
Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
- King Abdulazi University, Jeddah 21589, Saudi Arabia
| | - Larry A. Curtiss
- Materials
Science Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
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Lu J, Lei Y, Lau KC, Luo X, Du P, Wen J, Assary RS, Das U, Miller DJ, Elam JW, Albishri HM, El-Hady DA, Sun YK, Curtiss LA, Amine K. A nanostructured cathode architecture for low charge overpotential in lithium-oxygen batteries. Nat Commun 2013; 4:2383. [DOI: 10.1038/ncomms3383] [Citation(s) in RCA: 358] [Impact Index Per Article: 32.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Accepted: 07/31/2013] [Indexed: 12/24/2022] Open
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Lu J, Jung HJ, Lau KC, Zhang Z, Schlueter JA, Du P, Assary RS, Greeley J, Ferguson GA, Wang HH, Hassoun J, Iddir H, Zhou J, Zuin L, Hu Y, Sun YK, Scrosati B, Curtiss LA, Amine K. Magnetism in lithium-oxygen discharge product. ChemSusChem 2013; 6:1196-1202. [PMID: 23670967 DOI: 10.1002/cssc.201300223] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Indexed: 06/02/2023]
Abstract
Nonaqueous lithium-oxygen batteries have a much superior theoretical gravimetric energy density compared to conventional lithium-ion batteries, and thus could render long-range electric vehicles a reality. A molecular-level understanding of the reversible formation of lithium peroxide in these batteries, the properties of major/minor discharge products, and the stability of the nonaqueous electrolytes is required to achieve successful lithium-oxygen batteries. We demonstrate that the major discharge product formed in the lithium-oxygen cell, lithium peroxide, exhibits a magnetic moment. These results are based on dc-magnetization measurements and a lithium-oxygen cell containing an ether-based electrolyte. The results are unexpected because bulk lithium peroxide has a significant band gap. Density functional calculations predict that superoxide-type surface oxygen groups with unpaired electrons exist on stoichiometric lithium peroxide crystalline surfaces and on nanoparticle surfaces; these computational results are consistent with the magnetic measurement of the discharged lithium peroxide product as well as EPR measurements on commercial lithium peroxide. The presence of superoxide-type surface oxygen groups with spin can play a role in the reversible formation and decomposition of lithium peroxide as well as the reversible formation and decomposition of electrolyte molecules.
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Affiliation(s)
- Jun Lu
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, IL, USA
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Yang J, Zhai D, Wang HH, Lau KC, Schlueter JA, Du P, Myers DJ, Sun YK, Curtiss LA, Amine K. Evidence for lithium superoxide-like species in the discharge product of a Li–O2 battery. Phys Chem Chem Phys 2013; 15:3764-71. [DOI: 10.1039/c3cp00069a] [Citation(s) in RCA: 169] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Du P, Lu J, Lau KC, Luo X, Bareño J, Zhang X, Ren Y, Zhang Z, Curtiss LA, Sun YK, Amine K. Compatibility of lithium salts with solvent of the non-aqueous electrolyte in Li–O2 batteries. Phys Chem Chem Phys 2013; 15:5572-81. [DOI: 10.1039/c3cp50500f] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Lau KC, Dunlap BI. Molecular dynamics simulation of yttria-stabilized zirconia (YSZ) crystalline and amorphous solids. J Phys Condens Matter 2011; 23:035401. [PMID: 21406863 DOI: 10.1088/0953-8984/23/3/035401] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
An empirically fitted atomic potential allows a classical molecular dynamics study of the static and dynamic properties of both crystalline and amorphous yttria-stabilized zirconia (YSZ) with typical dilute Y(2)O(3) concentrations (i.e. 3.0-12.0 mol% Y(2)O(3)) in the temperature range 300-1400 K. Based on the rigid ion model approximation, we find, regardless of the distinctly different geometries, that the oxygen ionic conductivity shows a maximum at ∼ 8.0 mol% Y(2)O(3), close to the experimental maximum. A lower absolute ionic conductivity is found for the high density YSZ amorphous solid, relative to crystalline YSZ, consistent with the trends observed in crystalline and stabilized amorphous thin films of YSZ reported in experiments. Different from YSZ crystals, intriguing features of mutual diffusion among the heavy cations and mobile anions are found in the amorphous phase.
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Affiliation(s)
- Kah Chun Lau
- Department of Chemistry, George Washington University, Washington, DC 20052, USA
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Abstract
A study of lattice dielectric and thermodynamic properties of yttria stabilized zirconia (YSZ) crystals as a function of yttria concentration is reported. This study is based on density functional perturbation theory, using ABINIT. Within the local density approximation and the harmonic approximation, we find excellent agreement between calculated and low temperature experimental specific heat and dielectric constants. From the variation of the specific heat of YSZ with the yttria composition, we propose a simple additivity rule that estimates the dependence of the specific heat of YSZ on the yttria concentration, whereas for the dielectric constants of YSZ, the values are bounded by the dielectric constants of cubic and amorphous zirconia.
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Affiliation(s)
- Kah Chun Lau
- Department of Chemistry, George Washington University, Washington, DC 20052, USA
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Lau KC, Turner CH, Dunlap BI. Kinetic Monte Carlo simulation of O2- incorporation in the yttria stabilized zirconia (YSZ) fuel cell. Chem Phys Lett 2009. [DOI: 10.1016/j.cplett.2009.02.055] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Lau KC, Orlando R, Pandey R. Structure and stability of Mg-intercalated boron nanotubes and crystalline bundles. J Phys Condens Matter 2009; 21:045304. [PMID: 21715800 DOI: 10.1088/0953-8984/21/4/045304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
First principles calculations based on density functional theory predict a highly selective adsorption site for Mg atoms and negligible preference for the growth of Mg islands on the tubular surface of Mg-intercalated (small diameter) boron nanotubes, thereby establishing the criterion for understanding the growth mechanism of single-walled boron nanotubes (SWBNTs) supported by magnesium. On the other hand, the Mg-SWBNT bundles can be considered as an 'electrostatic' bound system consisting of partially ionized Mg and partially ionized tubules. The metallic character of the tubular Mg-B bundles is then attributed to boron atoms forming a metallic wire, while the role of Mg atoms is limited in enhancing the stability of the crystalline bundles.
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Affiliation(s)
- Kah Chun Lau
- Department of Physics, Michigan Technological University, Houghton, MI 49931, USA
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Affiliation(s)
- K C Lau
- The author is a technical manager at Datacolor International, Singapore
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35
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Affiliation(s)
- Kah Chun Lau
- Department of Chemistry, George Washington University, Washington, District of Columbia 20052, and Department of Physics, Michigan Technological University, Houghton, Michigan 49931
| | - Ravindra Pandey
- Department of Chemistry, George Washington University, Washington, District of Columbia 20052, and Department of Physics, Michigan Technological University, Houghton, Michigan 49931
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Li J, Yang J, Mo Y, Lau KC, Qian XM, Song Y, Liu J, Ng CY. Combined vacuum ultraviolet laser and synchrotron pulsed field ionization study of CH2BrCl. J Chem Phys 2007; 126:184304. [PMID: 17508800 DOI: 10.1063/1.2730829] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The pulsed field ionization-photoelectron (PFI-PE) spectrum of bromochloromethane (CH2BrCl) in the region of 85,320-88,200 cm-1 has been measured using vacuum ultraviolet laser. The vibrational structure resolved in the PFI-PE spectrum was assigned based on ab initio quantum chemical calculations and Franck-Condon factor predictions. At energies 0-1400 cm-1 above the adiabatic ionization energy (IE) of CH2BrCl, the Br-C-Cl bending vibration progression (nu1+=0-8) of CH2BrCl+ is well resolved and constitutes the major structure in the PFI-PE spectrum, whereas the spectrum at energies 1400-2600 cm-1 above the IE(CH2BrCl) is found to exhibit complex vibrational features, suggesting perturbation by the low lying excited CH2BrCl+(A 2A") state. The assignment of the PFI-PE vibrational bands gives the IE(CH2BrCl)=85,612.4+/-2.0 cm-1 (10.6146+/-0.0003 eV) and the bending frequencies nu1+(a1')=209.7+/-2.0 cm-1 for CH2BrCl+(X2A'). We have also examined the dissociative photoionization process, CH2BrCl+hnu-->CH2Cl++Br+e-, in the energy range of 11.36-11.57 eV using the synchrotron based PFI-PE-photoion coincidence method, yielding the 0 K threshold or appearance energy AE(CH2Cl+)=11.509+/-0.002 eV. Combining the 0 K AE(CH2Cl+) and IE(CH2BrCl) values obtained in this study, together with the known IE(CH2Cl), we have determined the 0 K bond dissociation energies (D0) for CH2Cl+-Br (0.894+/-0.002 eV) and CH2Cl-Br (2.76+/-0.01 eV). We have also performed CCSD(T, full)/complete basis set (CBS) calculations with high-level corrections for the predictions of the IE(CH2BrCl), AE(CH2Cl+), IE(CH2Cl), D0(CH2Cl+-Br), and D0(CH2Cl-Br). The comparison between the theoretical predictions and experimental determinations indicates that the CCSD(T, full)/CBS calculations with high-level corrections are highly reliable with estimated error limits of <17 meV.
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Affiliation(s)
- Juan Li
- Key Laboratory for Atomic and Molecular Nanosciences, Department of Physics, Tsinghua University, Beijing 10084, China
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Abstract
The rich chemistry of boron compounds are often found dominated by its structural dimensionality and chemical bonding from which some of the qualitative features of boron clusters can easily be extracted. In this article, we review such features to discuss structural properties of Bn clusters. In both small-cluster regime of n ≤ 20 and largecluster regime of n ≥ 20, the preferred topological structures are the result of the interplay between bonding factors related to the delocalized π bonds and the inter-icosahedral and intra-icosahedral bonds. The bulk fragments of boron are also expected to become a competitive isomeric configuration with the increase in the cluster-size, in contrast to 3D spherical cages observed in the large carbon clusters
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Lau KC, Kandalam AK, Costales A, Pandey R. Equilibrium geometry and electron detachment energies of anionic Cr2O4, Cr2O5, and Cr2O6 clusters. Chem Phys Lett 2004. [DOI: 10.1016/j.cplett.2004.06.020] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Qian XM, Lau KC, Ng CY. A high-resolution pulsed field ionization-photoelectron-photoion coincidence study of vinyl bromide. J Chem Phys 2004; 120:11031-41. [PMID: 15268133 DOI: 10.1063/1.1739402] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
By employing the high-resolution pulsed field ionization-photoelectron (PFI-PE)-photoion coincidence method, we have examined the unimolecular dissociation reaction of energy-selected C(2)H(3)Br(+) to form C(2)H(3) (+)+Br near its threshold. The analysis of the breakdown curves for C(2)H(3)Br(+) and C(2)H(3) (+) yields a value of 11.9010+/-0.0015 eV for the 0 K dissociative photoionization threshold or appearance energy (AE) for C(2)H(3) (+) from C(2)H(3)Br. This AE(C(2)H(3) (+)) value, together with the ionization energy (IE) for C(2)H(3)Br (9.8200+/-0.0015 eV) obtained by PFI-PE and threshold photoelectron (TPE) measurements, has allowed the determination of the 0 K dissociation energy (D(0)) for the C(2)H(3) (+)-Br bond to be 2.081+/-0.002 eV. The 0 K AE(C(2)H(3) (+)) from C(2)H(3)Br obtained in this study corresponds to DeltaH(f0) ( composite function )(C(2)H(3) (+))=1123.7+/-1.9 kJ/mol. Combining the latter value and the known DeltaH(f0) ( composite function )(C(2)H(3))=306.7+/-2.1 kJ/mol, we calculated a value of 8.468+/-0.029 eV for the IE(C(2)H(3)), which is in accord with the result obtained in the previous photoionization efficiency study. We have also carried out high-level ab initio calculations for the IE(C(2)H(3)) at the Gaussian-3 and the CCSD(T,full)/CBS level of theory. The CCSD(T,full)/CBS prediction of 8.487 eV for the IE(C(2)H(3)-->bridged-C(2)H(3) (+)) is in good agreement with the IE(C(2)H(3)) value derived in the present experiment. Combining the 0 K AE(C(2)H(3) (+))=11.9010+/-0.0015 eV and the IE(C(2)H(3))=8.468+/-0.029 eV yields the value of 3.433+/-0.029 eV for D(0)(C(2)H(3)-Br). We have also recorded the TPE spectrum of C(2)H(3)Br in the energy range of 9.80-12.20 eV. Members (n=5-14) of four autoionizing Rydberg series converging to the C(2)H(3)Br(+)(A (2)A(')) state are observed in the TPE spectrum. The analysis of the converging limit of these Rydberg series and the vibrational TPE bands for C(2)H(3)Br(+)(A (2)A(')) has provided more precise values for the nu(6) (+) (1217+/-10 cm(-1)) and nu(8) (+) (478+/-8 cm(-1)) modes and the IE (10.9156+/-0.0010 eV) for the formation of C(2)H(3)Br(+)(A (2)A(')) from C(2)H(3)Br.
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Affiliation(s)
- X M Qian
- Department of Chemistry, University of California at Davis, Davis, California 95616, USA
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Gowtham S, Lau KC, Deshpande M, Pandey R, Gianotto AK, Groenewold GS. Structure, Energetics, Electronic, and Hydration Properties of Neutral and Anionic Al3O6, Al3O7, and Al3O8 Clusters. J Phys Chem A 2004. [DOI: 10.1021/jp038040n] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Qian XM, Kung AH, Zhang T, Lau KC, Ng CY. Rovibrational-state-selected photoionization of acetylene by the two-color IR+VUV scheme: observation of rotationally resolved Rydberg transitions. Phys Rev Lett 2003; 91:233001. [PMID: 14683178 DOI: 10.1103/physrevlett.91.233001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2003] [Indexed: 05/24/2023]
Abstract
We have demonstrated a rovibrational-state-selected photoionization experiment using an IR laser and high-resolution VUV-synchrotron radiation. The VUV photoionization of acetylene [C2H2(Xtilde; (1)Sigma(+)(g);nu(3)=1,J(')=8 or 10)] prepared by IR excitation reveals three strong autoionizing Rydberg series converging to C2H+2(Xtilde; (2)Pi(u);nu(+)(3)=1) with little ion background interference. Rotational transitions resolved for the Rydberg states provide an estimate of approximately 1.8 ps for their lifetimes. This experiment opens the way for state-selective photoionization studies of polyatomic molecules using VUV-synchrotron radiation.
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Affiliation(s)
- X-M Qian
- Department of Chemistry, University of California, Davis, California 95616, USA
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Affiliation(s)
- Gary J Browne
- Department of Emergency Medicine and Adolph Basser Institute of Cardiology, Children's Hospital at Westmead, Royal Alexandra Hospital for Children, Sidney, Australia
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Thiagalingam A, Winlaw D, Hejmadi A, Kasahara S, Biankin S, Arbuckle S, Ross D, Lau KC, Nunn G. Images in cardiovascular medicine. Incessant ventricular tachycardia in an infant treated with transmural radiofrequency ablation. Circulation 2002; 105:2797-8. [PMID: 12057997 DOI: 10.1161/01.cir.0000014610.01057.ef] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Abstract
RATIONALE AND OBJECTIVES Multiculturalism presents linguistic obstacles to health care provision. We explored the early introduction of "interpreter" role-play exercises in teaching medical undergraduates communication skills. The interpreter role creates a natural barrier in communication providing an active prompt for recognizing learning needs in this area. METHODS Bilingual Cantonese first-year medical students (n=160) were randomly allocated to either "Observer" or "Interpreter" role plays at a small-group introductory communication skills workshop using a quasi experimental design, counterbalanced across tutors. Students assessed their own skill competence before and, together with their perceptions of the different role plays' effectiveness, again after the workshop, using an anonymous 16 item Likert-type scale, analysed using ANOVA and MANOVA. RESULTS Students' assessments of their skills improved significantly following the workshop (F=73.19 [1,156], P=0.0009). Students in the observer group reported greater changes in their scores following the workshop than did students in the interpreter group (F=4.84 [1,156], P=0.029), largely due to improvement in perceived skill (F=4.38 [1,156], P=0.038) rather than perceived programme effectiveness (F=3.13 [1,156], P > 0.05). Subsequent MANOVA indicated no main effect of observer/interpreter conditions, indicating these differences could be attributed to chance alone (F=1.41 [16 141], P > 0.05). CONCLUSION The workshop positively influenced students' perceived communication skills, but the "Interpreter" role was less effective than the "Observer" role in achieving this. Future studies should examine whether interpreter role plays introduced later in the medical programme are beneficial.
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Affiliation(s)
- K C Lau
- University Health Service, The University of Hong Kong, Hong Kong, ROC.
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Abstract
Over the past decade, the technique of radiofrequency ablation has evolved substantially. Currently, most forms of cardiac arrhythmias seen in children can be treated with good long-term results and low risk of adverse outcome. Curative arrhythmia treatment with this technique, however, is still uncommon in neonates and infants. Reported here is our experience in the management of an 8-week-old with drug-resistant permanent junctional reciprocating tachycardia.
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Affiliation(s)
- E Jaeggi
- Adolph Basser Cardiac Institute, Royal Alexandra Hospital for Children, University of Sydney, New South Wales, Australia.
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Nicholson IA, Nunn GR, Sholler GF, Hawker RE, Cooper SG, Lau KC, Cohn SL. Simplified single patch technique for the repair of atrioventricular septal defect. J Thorac Cardiovasc Surg 1999; 118:642-6. [PMID: 10504628 DOI: 10.1016/s0022-5223(99)70009-7] [Citation(s) in RCA: 94] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE Because of the complexity of traditional 1- and 2-patch techniques for the repair of complete atrioventricular septal defect, we modified our repair technique to avoid the use of any ventricular septal patch material. We report our prospective experience with this simplified 1-patch technique. METHOD Forty-seven consecutive patients between May 1995 and August 1998 underwent repair with the use of this technique without modification. Repair was done in all patients by direct suturing of the common atrioventricular valve leaflets to the crest of the ventricular septum. No division of valve leaflets was necessary. A single pericardial patch was used to close the defect in the atrial septal component. Follow-up included electrocardiography and echocardiographic assessment of ventricular function, atrioventricular valve function, and adequacy of the left ventricular outflow tract. RESULTS There were 2 deaths (4%), only 1 cardiac related, in the series. There were 17 male patients and 30 female patients. Mean age at repair was 5.6 months (median, 3.4 months). Associated lesions were repaired in 19 patients (40%). Mean follow-up was 1.85 years (median, 1.9 years). There was no heart block. There were no significant residual ventricular septal defects detected and no left ventricular outflow tract obstruction seen on echocardiography in any patient to date. Mitral valve status after operation was assessed as no incompetence in 13 patients (28%), minimal in 19 patients (40%), mild in 12 patients (26%), and moderate in 3 patients (6%). CONCLUSION The repair of complete atrioventricular septal defect by direct suturing of the atrioventricular valve leaflets to the crest of the ventricular septum with a single-patch technique greatly simplifies the repair and does not lead to left ventricular outflow tract obstruction nor interfere with valve function.
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Affiliation(s)
- I A Nicholson
- Adolph Basser Cardiac Institute, New Children's Hospital, Westmead, New South Wales, Australia
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Hornung TS, Sholler GF, Lau KC. Supraventricular electrical interaction in conjoined twins with common coronary sinus. Pacing Clin Electrophysiol 1999; 22:1416-8. [PMID: 10527028 DOI: 10.1111/j.1540-8159.1999.tb00640.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Conjoined twins with echocardiographic evidence of continuity of the coronary sinuses had identical heart rates on ECG. Both had broad, polyphasic QRS complexes, and various imaging modalities were unable to determine whether there was ventricular myocardial continuity. Administration of adenosine demonstrated that the broad polyphasic complexes were a "fusion" of the twins' individual QRS complexes, which could be clearly distinguished after administration of the drug. Ventricular pacing resulted in dissociation of the individual QRS complexes, thus demonstrating an absence of ventricular myocardial continuity. This was confirmed when the twins were successfully separated at the age of 10 months.
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Affiliation(s)
- T S Hornung
- Adolph Basser Cardiac Institute, Royal Alexandra Hospital for Children, Sydney, Australia
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Osborn DA, Lau KC, Uther JB, Coughtrey H, Rochefort MJ. Radiofrequency catheter ablation in a haemodynamically compromised premature neonate with hydrops fetalis. J Paediatr Child Health 1999; 35:406-8. [PMID: 10457304 DOI: 10.1046/j.1440-1754.1999.00367.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A preterm infant was born at 35 weeks gestation after failed antenatal antiarrhythmic therapy. The infant had an incessant supraventricular tachycardia, impaired ventricular function and hypotension and failed to respond to adenosine, cardioversion and intravenous amiodarone. After resuscitation from cardiovascular collapse, a successful radiofrequency catheter ablation (RFA) of a left free wall atrioventricular pathway was performed at 24 h of age without extracorporeal support. The infant is normal on follow up at 12 months of age. Whilst most fetal and neonatal supraventricular tachyarrhythmias respond to antiarrhythmic medications and RFA is not required, this is the earliest RFA to be performed on a premature infant when antiarrhythmics have failed.
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Affiliation(s)
- D A Osborn
- Neonatal Intensive Care Unit, Westmead Hospital, Westmead, Australia.
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Abstract
A 3-year-old girl presented with a febrile illness complicated by right ventricular outflow tract tachycardia, which persisted after resolution of the presumed viral infection. The tachycardia was intermittent, but was significantly exacerbated by exercise. Radiofrequency ablation (RFA) of the ectopic focus was successfully performed and the child remains free of tachycardia 12 months later. A review of the literature suggests that RFA in children is increasingly seen as a safe and convenient option for the treatment of supraventricular tachycardia, whereas the management of ectopic ventricular tachycardia in pediatric practice has not been well defined.
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Affiliation(s)
- T Millane
- Department of Pediatric Cardiology, Royal Alexandra Hospital for Children, Sydney, Australia
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Abstract
OBJECTIVE To assess the efficacy and safety of adenosine in the management of supraventricular tachycardia in children. METHODOLOGY A review of 43 children with supraventricular tachycardia who received intravenous adenosine between June 1992 and July 1995. RESULTS Thirty-five patients had re-entrant supraventricular tachycardia and eight patients had atrial tachydysrhythmias. Reversion to sinus rhythm occurred in 75% of episodes in all patients treated for supraventricular tachycardia, and in 96% of episodes in patients with re-entrant supraventricular tachycardia. Early re-initiation of supraventricular tachycardia after reversion to sinus rhythm occurred in 25% of episodes. Sixteen percent of patients reverted with the recommended 0.05 mg/kg starting dose, and 35% reverted with a dose of 0.1 mg/kg. Four patients were given adenosine as a diagnostic procedure to elicit occult pre-excitation. The most common side effects were brief feelings of discomfort. No serious side effects occurred. CONCLUSION Adenosine is safe and effective in the management of supraventricular tachycardia in children. A commencing dose of 0.1 mg/kg is appropriate.
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Affiliation(s)
- M C Sherwood
- Adolph Basser Cardiac Institute, Royal Alexandra Hospital for Children, Westmead, New South Wales, Australia
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