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Lun Z, Ouyang B, Cai Z, Clément RJ, Kwon DH, Huang J, Papp JK, Balasubramanian M, Tian Y, McCloskey BD, Ji H, Kim H, Kitchaev DA, Ceder G. Design Principles for High-Capacity Mn-Based Cation-Disordered Rocksalt Cathodes. Chem 2020. [DOI: 10.1016/j.chempr.2019.10.001] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Kim HW, Bukas VJ, Park H, Park S, Diederichsen KM, Lim J, Cho YH, Kim J, Kim W, Han TH, Voss J, Luntz AC, McCloskey BD. Mechanisms of Two-Electron and Four-Electron Electrochemical Oxygen Reduction Reactions at Nitrogen-Doped Reduced Graphene Oxide. ACS Catal 2019. [DOI: 10.1021/acscatal.9b04106] [Citation(s) in RCA: 106] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Diederichsen KM, Terrell RC, McCloskey BD. Counterion Transport and Transference Number in Aqueous and Nonaqueous Short-Chain Polyelectrolyte Solutions. J Phys Chem B 2019; 123:10858-10867. [PMID: 31747280 DOI: 10.1021/acs.jpcb.9b09517] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Nonaqueous polyelectrolyte solutions have recently been proposed as potential battery electrolytes due to their unique ability to tune the mobility of the anion relative to that of the electrochemically active lithium ion. This could potentially be used to study the effect of concentration polarization during battery charge, a major limiting factor in achieving fast charge rates that is caused by high anion mobility. An important consideration in the design of polyelectrolyte solutions for battery applications is the solubility of the polymer in battery-relevant carbonate blend solvents. Little is understood from a transport perspective, however, about the importance of designing the polymer to be solvophillic or if it is sufficient to obtain solubility through the incorporation of appended ions alone (as with polystyrene sulfonate in water). Using a model polysulfone-based system without added salt, we investigate the conductivity, viscosity, and diffusion of polyelectrolyte solutions over a range of concentrations and molecular weights in dimethyl sulfoxide (DMSO) and water. In both solvents, sulfonated polysulfone is readily soluble and the charged group is known to dissociate, but the neutral backbone polymer is only soluble in DMSO. We find marked differences in the transport behavior of polymer solutions prepared from the two solvents, particularly at high concentrations. Comparing this transport behavior to that of the monomer in solution demonstrates a larger decrease in lithium motion in DMSO than in water, even though the bulk viscosity in water increases far more rapidly. This study sheds light on the important parameters for optimizing polyelectrolyte solution transport in different solvents.
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Renfrew SE, Kaufman LA, McCloskey BD. Altering Surface Contaminants and Defects Influences the First-Cycle Outgassing and Irreversible Transformations of LiNi 0.6Mn 0.2Co 0.2O 2. ACS APPLIED MATERIALS & INTERFACES 2019; 11:34913-34921. [PMID: 31465196 DOI: 10.1021/acsami.9b09992] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
By altering the surface of LiNi0.6Mn0.2Co0.2O2 (NMC622) we show that surface defects and contaminants dominate the outgassing and irreversible surface transformations during the first electrochemical cycle. To alter the surface defects and contaminants without changing the bulk structure of the NMC622, we perform mild methanol and water rinses, a water soak, a water rinse and subsequent heat treatment, as well as purposeful increase of the surface Li2CO3. By combining isotopic labeling; gas analysis; and peroxide, hydroxide, and carbonate titrations we observe that these alterations change the surface Li2CO3, surface hydroxides, and the local defects, which in turn alter the nature and extent of the outgassing to O2 and CO2. Our results highlight that outgassing of Li-ion cathode materials is highly dependent on the synthesis and storage routes and comparison of varying compositions must take into account these differences to make any meaningful conclusions. We also show that simple rinsing procedures may be an effective route to controlling interfacial reactivity of Li-ion active materials.
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Huang W, Attia PM, Wang H, Renfrew SE, Jin N, Das S, Zhang Z, Boyle DT, Li Y, Bazant MZ, McCloskey BD, Chueh WC, Cui Y. Evolution of the Solid-Electrolyte Interphase on Carbonaceous Anodes Visualized by Atomic-Resolution Cryogenic Electron Microscopy. NANO LETTERS 2019; 19:5140-5148. [PMID: 31322896 DOI: 10.1021/acs.nanolett.9b01515] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The stability of modern lithium-ion batteries depends critically on an effective solid-electrolyte interphase (SEI), a passivation layer that forms on the carbonaceous negative electrode as a result of electrolyte reduction. However, a nanoscopic understanding of how the SEI evolves with battery aging remains limited due to the difficulty in characterizing the structural and chemical properties of this sensitive interphase. In this work, we image the SEI on carbon black negative electrodes using cryogenic transmission electron microscopy (cryo-TEM) and track its evolution during cycling. We find that a thin, primarily amorphous SEI nucleates on the first cycle, which further evolves into one of two distinct SEI morphologies upon further cycling: (1) a compact SEI, with a high concentration of inorganic components that effectively passivates the negative electrode; and (2) an extended SEI spanning hundreds of nanometers. This extended SEI grows on particles that lack a compact SEI and consists primarily of alkyl carbonates. The diversity in observed SEI morphologies suggests that SEI growth is a highly heterogeneous process. The simultaneous emergence of these distinct SEI morphologies highlights the necessity of effective passivation by the SEI, as large-scale extended SEI growths negatively impact lithium-ion transport, contribute to capacity loss, and may accelerate battery failure.
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Fong KD, Self J, Diederichsen KM, Wood BM, McCloskey BD, Persson KA. Ion Transport and the True Transference Number in Nonaqueous Polyelectrolyte Solutions for Lithium Ion Batteries. ACS CENTRAL SCIENCE 2019; 5:1250-1260. [PMID: 31403073 PMCID: PMC6661974 DOI: 10.1021/acscentsci.9b00406] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2019] [Indexed: 05/14/2023]
Abstract
Nonaqueous polyelectrolyte solutions have been recently proposed as high Li+ transference number electrolytes for lithium ion batteries. However, the atomistic phenomena governing ion diffusion and migration in polyelectrolytes are poorly understood, particularly in nonaqueous solvents. Here, the structural and transport properties of a model polyelectrolyte solution, poly(allyl glycidyl ether-lithium sulfonate) in dimethyl sulfoxide, are studied using all-atom molecular dynamics simulations. We find that the static structural analysis of Li+ ion pairing is insufficient to fully explain the overall conductivity trend, necessitating a dynamic analysis of the diffusion mechanism, in which we observe a shift from largely vehicular transport to more structural diffusion as the Li+ concentration increases. Furthermore, we demonstrate that despite the significantly higher diffusion coefficient of the lithium ion, the negatively charged polyion is responsible for the majority of the solution conductivity at all concentrations, corresponding to Li+ transference numbers much lower than previously estimated experimentally. We quantify the ion-ion correlations unique to polyelectrolyte systems that are responsible for this surprising behavior. These results highlight the need to reconsider the approximations typically made for transport in polyelectrolyte solutions.
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Abbott LJ, Buss HG, Thelen JL, McCloskey BD, Lawson JW. Polyanion Electrolytes with Well-Ordered Ionic Layers in Simulations and Experiment. Macromolecules 2019. [DOI: 10.1021/acs.macromol.9b00416] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Hsu CH, Ma C, Bui N, Song Z, Wilson AD, Kostecki R, Diederichsen KM, McCloskey BD, Urban JJ. Enhanced Forward Osmosis Desalination with a Hybrid Ionic Liquid/Hydrogel Thermoresponsive Draw Agent System. ACS OMEGA 2019; 4:4296-4303. [PMID: 31459634 PMCID: PMC6648795 DOI: 10.1021/acsomega.8b02827] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Accepted: 01/04/2019] [Indexed: 06/10/2023]
Abstract
Forward osmosis (FO) has emerged as a new technology for desalination and exhibits potentials for applications where reverse osmosis is incapable or uneconomical for treating streams with high salinity or fouling propensity. However, most of current draw agents in FO are salts and difficult to be recycled cost- and energy-effectively. In this work, we demonstrate a new and facile approach to efficiently recover water from the FO process with enhanced water purity by using a binary ion liquid/hydrogel system. The hybrid ion liquid/hydrogel draw solution system demonstrated in this work synergistically leverages the thermoresponsive properties of both the ionic liquid (IL) and hydrogel to improve the overall FO performance. Our findings corroborate that the hydrogel mitigates the water flux decline of the IL as the draw agent and provide a ready route to contiguously and effectively regenerate water from the FO process. Such a route allows for an efficient recovery of water from the draw solute/water mixture with enhanced water purity, compared with conventional thermal treating of lower critical solution temperature IL draw solute/water. Furthermore, hydrogels can be used in a continuous and readily recyclable process to recover water without heating the entire draw solute/water mixture. Our design principles open the door to use low-grade/waste heat or solar energy to regenerate draw agents and potentially reduce energy in the FO process considerably.
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Bukas VJ, Kim HW, Sengpiel R, Knudsen K, Voss J, McCloskey BD, Luntz AC. Combining Experiment and Theory To Unravel the Mechanism of Two-Electron Oxygen Reduction at a Selective and Active Co-catalyst. ACS Catal 2018. [DOI: 10.1021/acscatal.8b02813] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Shin Y, Kan WH, Aykol M, Papp JK, McCloskey BD, Chen G, Persson KA. Alleviating oxygen evolution from Li-excess oxide materials through theory-guided surface protection. Nat Commun 2018; 9:4597. [PMID: 30389938 PMCID: PMC6214920 DOI: 10.1038/s41467-018-07080-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 10/09/2018] [Indexed: 11/16/2022] Open
Abstract
Li-excess cathodes comprise one of the most promising avenues for increasing the energy density of current Li-ion technology. However, the first-cycle surface oxygen release in these materials causes cation densification and structural reconstruction of the surface region, leading to encumbered ionic transport and increased impedance. In this work, we use the first principles Density Functional Theory to systematically screen for optimal cation dopants to improve oxygen-retention at the surface. The initial dopant set includes all transition metal, post-transition metal, and metalloid elements. Our screening identifies Os, Sb, Ru, Ir, or Ta as high-ranking dopants considering the combined criteria, and rationalization based on the electronic structure of the top candidates are presented. To validate the theoretical screening, a Ta-doped Li1.3Nb0.3Mn0.4O2 cathode was synthesized and shown to present initial improved electrochemical performance as well as significantly reduced oxygen evolution, as compared with the pristine, un-doped, system. Rechargeable Li-ion batteries can show extensive oxygen loss from the cathode material under operating conditions. Here, the authors use high-throughput computational screening to guide the synthesis of a Tantalum-doped Li-excess cathode that significantly reduces oxygen loss.
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Sun Y, Radke CJ, McCloskey BD, Prausnitz JM. Wetting behavior of four polar organic solvents containing one of three lithium salts on a lithium-ion-battery separator. J Colloid Interface Sci 2018; 529:582-587. [DOI: 10.1016/j.jcis.2018.06.044] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 06/18/2018] [Accepted: 06/19/2018] [Indexed: 11/25/2022]
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37
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Diederichsen KM, Fong KD, Terrell RC, Persson KA, McCloskey BD. Investigation of Solvent Type and Salt Addition in High Transference Number Nonaqueous Polyelectrolyte Solutions for Lithium Ion Batteries. Macromolecules 2018. [DOI: 10.1021/acs.macromol.8b01696] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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38
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Tesfaye M, Kushner DI, McCloskey BD, Weber AZ, Kusoglu A. Thermal Transitions in Perfluorosulfonated Ionomer Thin-Films. ACS Macro Lett 2018; 7:1237-1242. [PMID: 35651261 DOI: 10.1021/acsmacrolett.8b00628] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Thin perfluorosulfonated ion-conducting polymers (PFSI ionomers) in energy-conversion devices have limitations in functionality attributed to confinement-driven and surface-dependent interactions. This study highlights the effects of confinement and interface-dependent interactions of PFSI thin-films by exploring thin-film thermal transition temperature (TT). Change in TT in polymers is an indicator for chain relaxation and mobility with implications on properties like gas transport. This work demonstrates an increase in TT with decreasing PFSI film thickness in acid (H+) form (from 70 to 130 °C for 400 to 10 nm, respectively). In metal cation (M+) exchanged PFSI, TT remained constant with thickness. Results point to an interplay between increased chain mobility at the free surface and hindered motion near the rigid substrate interface, which is amplified upon further confinement. This balance is additionally impacted by ionomer intermolecular forces, as strong electrostatic networks within the PFSI-M+ matrix raises TT above the mainly hydrogen-bonded PFSI-H+ ionomer.
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Liyana-Arachchi TP, Haskins JB, Burke CM, Diederichsen KM, McCloskey BD, Lawson JW. Polarizable Molecular Dynamics and Experiments of 1,2-Dimethoxyethane Electrolytes with Lithium and Sodium Salts: Structure and Transport Properties. J Phys Chem B 2018; 122:8548-8559. [DOI: 10.1021/acs.jpcb.8b03445] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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40
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Berlinger SA, McCloskey BD, Weber AZ. Inherent Acidity of Perfluorosulfonic Acid Ionomer Dispersions and Implications for Ink Aggregation. J Phys Chem B 2018; 122:7790-7796. [PMID: 30016864 DOI: 10.1021/acs.jpcb.8b06493] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Perfluorosulfonic acid (PFSA) dispersions are used as components in a variety of electrochemical technologies, particularly in fuel-cell catalyst-layer inks. In this study, we characterize dispersions of a common PFSA, Nafion, as well as inks of Nafion and carbon. It is shown that solvent choice affects a dispersion's measured pH, which is found to scale linearly with Nafion loading. Dispersions in water-rich solvents are more acidic than those in propanol-rich solvents: a 90% water versus 30% water dispersion can have up to a 55% measured proton deviation. Furthermore, because electrostatic interactions are a function of pH, these differences affect how particles aggregate in solution. Despite having different water contents, all inks studied demonstrate the same particle size and surface charge trends as a function of pH, thus providing insights into the relative influence of solvent and pH effects on these properties.
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Corson ER, Creel EB, Kim Y, Urban JJ, Kostecki R, McCloskey BD. A temperature-controlled photoelectrochemical cell for quantitative product analysis. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:055112. [PMID: 29864888 DOI: 10.1063/1.5024802] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
In this study, we describe the design and operation of a temperature-controlled photoelectrochemical cell for analysis of gaseous and liquid products formed at an illuminated working electrode. This cell is specifically designed to quantitatively analyze photoelectrochemical processes that yield multiple gas and liquid products at low current densities and exhibit limiting reactant concentrations that prevent these processes from being studied in traditional single chamber electrolytic cells. The geometry of the cell presented in this paper enables front-illumination of the photoelectrode and maximizes the electrode surface area to electrolyte volume ratio to increase liquid product concentration and hence enhances ex situ spectroscopic sensitivity toward them. Gas is bubbled through the electrolyte in the working electrode chamber during operation to maintain a saturated reactant concentration and to continuously mix the electrolyte. Gaseous products are detected by an in-line gas chromatograph, and liquid products are analyzed ex situ by nuclear magnetic resonance. Cell performance was validated by examining carbon dioxide reduction on a silver foil electrode, showing comparable results both to those reported in the literature and identical experiments performed in a standard parallel-electrode electrochemical cell. To demonstrate a photoelectrochemical application of the cell, CO2 reduction experiments were carried out on a plasmonic nanostructured silver photocathode and showed different product distributions under dark and illuminated conditions.
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Mahne N, Renfrew SE, McCloskey BD, Freunberger SA. Electrochemical Oxidation of Lithium Carbonate Generates Singlet Oxygen. Angew Chem Int Ed Engl 2018. [PMID: 29543372 PMCID: PMC5947587 DOI: 10.1002/anie.201802277] [Citation(s) in RCA: 83] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Solid alkali metal carbonates are universal passivation layer components of intercalation battery materials and common side products in metal‐O2 batteries, and are believed to form and decompose reversibly in metal‐O2/CO2 cells. In these cathodes, Li2CO3 decomposes to CO2 when exposed to potentials above 3.8 V vs. Li/Li+. However, O2 evolution, as would be expected according to the decomposition reaction 2 Li2CO3→4 Li++4 e−+2 CO2+O2, is not detected. O atoms are thus unaccounted for, which was previously ascribed to unidentified parasitic reactions. Here, we show that highly reactive singlet oxygen (1O2) forms upon oxidizing Li2CO3 in an aprotic electrolyte and therefore does not evolve as O2. These results have substantial implications for the long‐term cyclability of batteries: they underpin the importance of avoiding 1O2 in metal‐O2 batteries, question the possibility of a reversible metal‐O2/CO2 battery based on a carbonate discharge product, and help explain the interfacial reactivity of transition‐metal cathodes with residual Li2CO3.
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Mahne N, Renfrew SE, McCloskey BD, Freunberger SA. Elektrochemische Oxidation von Lithiumcarbonat generiert Singulett‐Sauerstoff. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201802277] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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44
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Lee J, Kitchaev DA, Kwon DH, Lee CW, Papp JK, Liu YS, Lun Z, Clément RJ, Shi T, McCloskey BD, Guo J, Balasubramanian M, Ceder G. Reversible Mn 2+/Mn 4+ double redox in lithium-excess cathode materials. Nature 2018; 556:185-190. [PMID: 29643482 DOI: 10.1038/s41586-018-0015-4] [Citation(s) in RCA: 180] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Accepted: 02/06/2018] [Indexed: 11/09/2022]
Abstract
There is an urgent need for low-cost, resource-friendly, high-energy-density cathode materials for lithium-ion batteries to satisfy the rapidly increasing need for electrical energy storage. To replace the nickel and cobalt, which are limited resources and are associated with safety problems, in current lithium-ion batteries, high-capacity cathodes based on manganese would be particularly desirable owing to the low cost and high abundance of the metal, and the intrinsic stability of the Mn4+ oxidation state. Here we present a strategy of combining high-valent cations and the partial substitution of fluorine for oxygen in a disordered-rocksalt structure to incorporate the reversible Mn2+/Mn4+ double redox couple into lithium-excess cathode materials. The lithium-rich cathodes thus produced have high capacity and energy density. The use of the Mn2+/Mn4+ redox reduces oxygen redox activity, thereby stabilizing the materials, and opens up new opportunities for the design of high-performance manganese-rich cathodes for advanced lithium-ion batteries.
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Kim HW, Ross MB, Kornienko N, Zhang L, Guo J, Yang P, McCloskey BD. Efficient hydrogen peroxide generation using reduced graphene oxide-based oxygen reduction electrocatalysts. Nat Catal 2018. [DOI: 10.1038/s41929-018-0044-2] [Citation(s) in RCA: 449] [Impact Index Per Article: 74.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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46
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Xu J, Sun M, Qiao R, Renfrew SE, Ma L, Wu T, Hwang S, Nordlund D, Su D, Amine K, Lu J, McCloskey BD, Yang W, Tong W. Elucidating anionic oxygen activity in lithium-rich layered oxides. Nat Commun 2018; 9:947. [PMID: 29507369 PMCID: PMC5838240 DOI: 10.1038/s41467-018-03403-9] [Citation(s) in RCA: 99] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 02/12/2018] [Indexed: 12/16/2022] Open
Abstract
Recent research has explored combining conventional transition-metal redox with anionic lattice oxygen redox as a new and exciting direction to search for high-capacity lithium-ion cathodes. Here, we probe the poorly understood electrochemical activity of anionic oxygen from a material perspective by elucidating the effect of the transition metal on oxygen redox activity. We study two lithium-rich layered oxides, specifically lithium nickel metal oxides where metal is either manganese or ruthenium, which possess a similar structure and discharge characteristics, but exhibit distinctly different charge profiles. By combining X-ray spectroscopy with operando differential electrochemical mass spectrometry, we reveal completely different oxygen redox activity in each material, likely resulting from the different interaction between the lattice oxygen and transition metals. This work provides additional insights into the complex mechanism of oxygen redox and development of advanced high-capacity lithium-ion cathodes. A reversible oxygen redox process contributes extra capacity and understanding this behavior is of high importance. Here, aided by resonant inelastic X-ray scattering, the authors reveal the distinctive anionic oxygen activity of battery electrodes with different transition metals.
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Renfrew SE, McCloskey BD. Residual Lithium Carbonate Predominantly Accounts for First Cycle CO2 and CO Outgassing of Li-Stoichiometric and Li-Rich Layered Transition-Metal Oxides. J Am Chem Soc 2017; 139:17853-17860. [DOI: 10.1021/jacs.7b08461] [Citation(s) in RCA: 212] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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48
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Lee J, Papp JK, Clément RJ, Sallis S, Kwon DH, Shi T, Yang W, McCloskey BD, Ceder G. Mitigating oxygen loss to improve the cycling performance of high capacity cation-disordered cathode materials. Nat Commun 2017; 8:981. [PMID: 29042560 PMCID: PMC5645360 DOI: 10.1038/s41467-017-01115-0] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 08/20/2017] [Indexed: 11/09/2022] Open
Abstract
Recent progress in the understanding of percolation theory points to cation-disordered lithium-excess transition metal oxides as high-capacity lithium-ion cathode materials. Nevertheless, the oxygen redox processes required for these materials to deliver high capacity can trigger oxygen loss, which leads to the formation of resistive surface layers on the cathode particles. We demonstrate here that, somewhat surprisingly, fluorine can be incorporated into the bulk of disordered lithium nickel titanium molybdenum oxides using a standard solid-state method to increase the nickel content, and that this compositional modification is very effective in reducing oxygen loss, improving energy density, average voltage, and rate performance. We argue that the valence reduction on the anion site, offered by fluorine incorporation, opens up significant opportunities for the design of high-capacity cation-disordered cathode materials.The performance of lithium-excess cation-disordered oxides as cathode materials relies on the extent to which the oxygen loss during cycling is mitigated. Here, the authors show that incorporating fluorine is an effective strategy which substantially improves the cycling stability of such a material.
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Asenbauer J, Ben Hassen N, McCloskey BD, Prausnitz JM. Solubilities and ionic conductivities of ionic liquids containing lithium salts. Electrochim Acta 2017. [DOI: 10.1016/j.electacta.2017.07.053] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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50
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Diederichsen KM, Buss HG, McCloskey BD. The Compensation Effect in the Vogel–Tammann–Fulcher (VTF) Equation for Polymer-Based Electrolytes. Macromolecules 2017. [DOI: 10.1021/acs.macromol.7b00423] [Citation(s) in RCA: 173] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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