Understanding and applying coulombic efficiency in lithium metal batteries

Xiao, Jie; Li, Qiuyan; Bi, Yujing; Cai, Mei; Dunn, Bruce; Glossmann, Tobias; Li, Jun; Osaka, Tetsuya; Sugiura, Ryuta; Wu, Bingbin; Yang, Jihui; Zhang, Ji Guang; Whittingham, M. Stanley

doi:10.1038/s41560-020-0648-z

Cited by 674 publications

(544 citation statements)

References 26 publications

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“…However, in LMBs, CE usually does not correlate well with the cycle life. [ 124 ] Unlike the Gr based LIBs, the SEI on Li metal undergoes repetitive fracture and regeneration upon Li plating/stripping. When fresh Li is exposed to the liquid electrolyte, both spontaneous chemical and electrochemical reactions take place.…”

Section: Correlation Of Solid Electrolyte Interphase On Electrochemicmentioning

confidence: 99%

Recent Progress in Understanding Solid Electrolyte Interphase on Lithium Metal Anodes

Jia

Wang

et al. 2020

Advanced Energy Materials

329

339

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Lithium metal batteries (LMBs) are one of the most promising candidates for next‐generation high‐energy‐density rechargeable batteries. Solid electrolyte interphase (SEI) on Li metal anodes plays a significant role in influencing the Li deposition morphology and the cycle life of LMBs. However, a thorough understanding on the mechanisms of SEI formation and evolution is still inadequate. In this review, the progress in understanding structures, properties, and influencing factors of SEI, as well as efficient strategies of tailoring SEI are focused upon. First, the compositions, models, and recent progress in characterizing atomic structures of SEI are summarized. Second, the properties of SEI, including electronic conduction, ionic conduction, stability, and mechanical properties are elucidated. Structures and properties of SEI are greatly affected by multiple factors, thus interactions between these factors and SEI are systematically discussed. Correlations of SEI with Li deposition morphology, rate capability, and cycle life are further summarized. Moreover, efficient strategies of tailoring SEI with desired properties, including in situ SEI and ex situ SEI, are also reviewed. Finally, future directions, including in‐operando techniques, multi‐modality approaches for characterization of SEI, and artificial intelligence assisted understanding of correlations between electrolyte components and SEI properties are proposed.

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Section: Correlation Of Solid Electrolyte Interphase On Electrochemicmentioning

confidence: 99%

Recent Progress in Understanding Solid Electrolyte Interphase on Lithium Metal Anodes

Jia

Wang

et al. 2020

Advanced Energy Materials

329

339

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“…The low capacity retention of LMBs is often overlooked because an excess amount of Li metal is typically used in research-scale cells, which leads to an artificially enhanced cycling efficiency. 3 − 5 However, for practical, commercially viable cells, it is important to limit the amount of excess Li in order to make use of the high specific capacity of Li metal anodes. Practical LMBs will need to have the so-called negative-to-positive (N:P) ratio as close to 1:1 as possible, that is, an amount of Li metal close to that needed to fully lithiate the positive cathode material.…”

Section: Introductionmentioning

confidence: 99%

Noninvasive In Situ NMR Study of “Dead Lithium” Formation and Lithium Corrosion in Full-Cell Lithium Metal Batteries

et al. 2020

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Capacity retention in lithium metal batteries needs to be improved if they are to be commercially viable, the low cycling stability and Li corrosion during storage of lithium metal batteries being even more problematic when there is no excess lithium in the cell. Herein, we develop in situ NMR metrology to study “anode-free” lithium metal batteries where lithium is plated directly onto a bare copper current collector from a LiFePO4 cathode. The methodology allows inactive or “dead lithium” formation during plating and stripping of lithium in a full-cell lithium metal battery to be tracked: dead lithium and SEI formation can be quantified by NMR and their relative rates of formation are here compared in carbonate and ether-electrolytes. Little-to-no dead Li was observed when FEC is used as an additive. The bulk magnetic susceptibility effects arising from the paramagnetic lithium metal were used to distinguish between different surface coverages of lithium deposits. The amount of lithium metal was monitored during rest periods, and lithium metal dissolution (corrosion) was observed in all electrolytes, even during the periods when the battery is not in use, i.e., when no current is flowing, demonstrating that dissolution of lithium remains a critical issue for lithium metal batteries. The high rate of corrosion is attributed to SEI formation on both lithium metal and copper (and Cu+, Cu2+ reduction). Strategies to mitigate the corrosion are explored, the work demonstrating that both polymer coatings and the modification of the copper surface chemistry help to stabilize the lithium metal surface.

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“…The capacitance of the ASC was even increased to 109% after 1000 cyclic tests, as shown in Figure 5 c. This is in contrast with our recently reported result of PANI symmetric capacitors with the similar redox active electrolyte, which was so unstable that only ~50% capacitance was retained after 1000 cycles [ 18 ]. Moreover, the coulombic efficiency was increased from 84% for the first cycle and remained stable at a high level of nearly 90% after 100 cycles, indicating a good reversibility of the ASC [ 33 ].…”

Section: Resultsmentioning

confidence: 99%

Electrodeposited Polyaniline Nanofibers and MoO3 Nanobelts for High-Performance Asymmetric Supercapacitor with Redox Active Electrolyte

Meng

Xia

et al. 2020

Polymers

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Transition molybdenum oxides (MoO3) and conductive polymer (polyaniline, PANI) nanomaterials were fabricated and asymmetric supercapacitor (ASC) was assembled with MoO3 nanobelts as negative electrode and PANI nanofibers as a positive electrode. Branched PANI nanofibers with a diameter of 100 nm were electrodeposited on Ti mesh substrate and MoO3 nanobelts with width of 30–700 nm were obtained by the hydrothermal reaction method in an autoclave. Redox active electrolyte containing 0.1 M Fe2+/3+ redox couple was adopted in order to enhance the electrochemical performance of the electrode nano-materials. As a result, the PANI electrode shows a great capacitance of 3330 F g−1 at 1 A g−1 in 0.1 M Fe2+/3+/0.5 M H2SO4 electrolyte. The as-assembled ASC achieved a great energy density of 54 Wh kg−1 at power density of 900 W kg−1. In addition, it displayed significant cycle stability and its capacitance even increased to 109% of the original value after 1000 charge–discharge cycles. The superior performance of the capacitors indicates their promising application as energy storage devices.

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Understanding and applying coulombic efficiency in lithium metal batteries

Cited by 674 publications

References 26 publications

Recent Progress in Understanding Solid Electrolyte Interphase on Lithium Metal Anodes

Recent Progress in Understanding Solid Electrolyte Interphase on Lithium Metal Anodes

Noninvasive In Situ NMR Study of “Dead Lithium” Formation and Lithium Corrosion in Full-Cell Lithium Metal Batteries

Electrodeposited Polyaniline Nanofibers and MoO3 Nanobelts for High-Performance Asymmetric Supercapacitor with Redox Active Electrolyte

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