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Geng F, Lu G, Liao Y, Shen M, Hu B. Quantitative and space-resolved in situ 1D EPR imaging for the detection of metallic lithium deposits. J Chem Phys 2022; 157:174203. [DOI: 10.1063/5.0125080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The ability to monitor lithium deposition on the anodes in real time is becoming progressively more important due to the development of advanced anode technology. Given the fact that the detrimental Li deposits are always on the micron scale, electron paramagnetic resonance (EPR) happens to be a very effective and selective detection technology due to the skin effect. Here, quantitative in situ 1D EPR imaging is carried out with a magnetic field gradient to achieve a one-dimensional spatial resolution along the Li growth direction in a capillary cell. The quantification of Li deposits is carefully calibrated using a 1,1-diphenyl-2-picrylhydrazyl standard, and a processing method is presented to correct the double integration of the Dysonian line from the metallic Li. The Li deposition processes are compared in two different electrolytes. For the electrolyte containing fluoroethylene carbonate (FEC) additive, the fitting results of Dysonian lines suggest that the plated Li has a larger dimension of the microstructure and the stripping proceeds more uniformly. It thus accounts for the higher Coulombic efficiency in the electrolyte with FEC. In situ EPR imaging also suggests that the Sand’s capacity varies with the electrolytes. The forced growth of dendritic Li is carried out at a very large current density using a derivative operando EPR method to monitor the growth locus of the Li dendrites, indicating a tip-growing mechanism. This work can be instructive for those who are engaged in the study of electro-deposited lithium using in situ EPR imaging technology.
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Affiliation(s)
- Fushan Geng
- Shanghai Key Laboratory of Magnetic Resonance, State Key Laboratory of Precision Spectroscopy, School of Physics and Electronic Science, East China Normal University, Shanghai 200062, People's Republic of China
| | - Guozhong Lu
- Shanghai Key Laboratory of Magnetic Resonance, State Key Laboratory of Precision Spectroscopy, School of Physics and Electronic Science, East China Normal University, Shanghai 200062, People's Republic of China
| | - Yuxin Liao
- Shanghai Key Laboratory of Magnetic Resonance, State Key Laboratory of Precision Spectroscopy, School of Physics and Electronic Science, East China Normal University, Shanghai 200062, People's Republic of China
| | - Ming Shen
- Shanghai Key Laboratory of Magnetic Resonance, State Key Laboratory of Precision Spectroscopy, School of Physics and Electronic Science, East China Normal University, Shanghai 200062, People's Republic of China
| | - Bingwen Hu
- Shanghai Key Laboratory of Magnetic Resonance, State Key Laboratory of Precision Spectroscopy, School of Physics and Electronic Science, East China Normal University, Shanghai 200062, People's Republic of China
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den Hartog S, Neukermans S, Samanipour M, Ching HV, Breugelmans T, Hubin A, Ustarroz J. Electrocatalysis under a magnetic lens: A combined electrochemistry and electron paramagnetic resonance review. Electrochim Acta 2022. [DOI: 10.1016/j.electacta.2021.139704] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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McKenzie ECR, Hosseini S, Petro AGC, Rudman KK, Gerroll BHR, Mubarak MS, Baker LA, Little RD. Versatile Tools for Understanding Electrosynthetic Mechanisms. Chem Rev 2021; 122:3292-3335. [PMID: 34919393 DOI: 10.1021/acs.chemrev.1c00471] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Electrosynthesis is a popular, green alternative to traditional organic methods. Understanding the mechanisms is not trivial yet is necessary to optimize reaction processes. To this end, a multitude of analytical tools is available to identify and quantitate reaction products and intermediates. The first portion of this review serves as a guide that underscores electrosynthesis fundamentals, including instrumentation, electrode selection, impacts of electrolyte and solvent, cell configuration, and methods of electrosynthesis. Next, the broad base of analytical techniques that aid in mechanism elucidation are covered in detail. These methods are divided into electrochemical, spectroscopic, chromatographic, microscopic, and computational. Technique selection is dependent on predicted reaction pathways and electrogenerated intermediates. Often, a combination of techniques must be utilized to ensure accuracy of the proposed model. To conclude, future prospects that aim to enhance the field are discussed.
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Affiliation(s)
- Eric C R McKenzie
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Seyyedamirhossein Hosseini
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112, United States
| | - Ana G Couto Petro
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Kelly K Rudman
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Benjamin H R Gerroll
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | | | - Lane A Baker
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - R Daniel Little
- Department of Chemistry, University of California Santa Barbara, Building 232, Santa Barbara, California 93106, United States
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Tamski M, Milani J, Roussel C, Ansermet JP. Electrochemical Overhauser dynamic nuclear polarization. Phys Chem Chem Phys 2020; 22:17769-17776. [PMID: 32766651 DOI: 10.1039/d0cp00984a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Nuclear Magnetic Resonance (NMR) spectroscopy suffers from low sensitivity due to the low nuclear spin polarization obtained within practically achievable external magnetic fields. Dynamic Nuclear Polarization (DNP) refers to techniques that increase the NMR signal intensity by transferring spin polarization from electrons to the nuclei. Until now, a common method of introducing unpaired electrons to a sample has been to add to it a radical such as TEMPOL or trityl. The alternative we address here is to use electrochemical oxidation and/or reduction of a redox mediator to generate radical species that can be used for DNP. Surprisingly, the potential of electrochemically-generated radicals as a source of hyperpolarization for DNP has not been investigated so far. In this communication, we show the proof of principle of performing an in situ DNP experiment at a low magnetic field in a solution phase, with electrochemically generated methyl viologen cation radicals. Electrochemistry as a source of radicals can offer exciting prospects for DNP. The electrode may be one that generates radicals with a high spin polarization. The concentration of radicals in the sample can be adjusted by changing the duration and magnitude of the applied electrode potential. Removal of the radical from the sample after spin polarization transfer is also possible, thereby increasing the lifetime of the nuclear hyperpolarization.
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Affiliation(s)
- Mika Tamski
- Institut de physique, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
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Lee KJ, Elgrishi N, Kandemir B, Dempsey JL. Electrochemical and spectroscopic methods for evaluating molecular electrocatalysts. Nat Rev Chem 2017. [DOI: 10.1038/s41570-017-0039] [Citation(s) in RCA: 123] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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