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Influence of electrolyte on lithium cycling efficiency with pressurized electrode stack

Journal Article · · Journal of the Electrochemical Society; (United States)
DOI:https://doi.org/10.1149/1.2054778· OSTI ID:7039015
; ;  [1]
  1. NTT Interdisciplinary Research Lab., Ibaraki (Japan)

The limited cycle life of rechargeable lithium cells has been one of the most important barriers for developing commercial cells and many factors have been investigated in attempts to improve cycle ability. The dependency of lithium cycling efficiency on stack pressure was studied for several electrolytes. To evaluate the cycling efficiency E, the authors calculated the figure of merit (FOM) of lithium as FOM = 1/(1-E). The effect of solvents on the FOM change with pressure was examined for LiAsF[sub 6] solute electrolytes containing 2-methyltetrahydrofuran (2MeTHF), ethylene carbonate (EC)/2MeTHF, propylene carbonate (PC), or EC/PC. The electrolyte LiAsF[sub 6]-EC/2MeTHF showed the largest FOM (80 at 125 kg/cm[sup 2]). With the electrolytes LiAsF[sub 6] [minus] PC and LiAsF[sub 6]-EC/PC, FOM was less dependent on stack pressure than it was with the electrolytes LiAsF[sub 6]-2MeTHF and EC/2MeTHF, probably because a different separator was used for the former electrolytes. Examining the effect of the solute on the FOM change with pressure showed that the FOMs for LiPF[sub 6]- and LiCF[sub 3]SO[sub 3]-EC/2MeTHF reached maximum values at 50 and 75 kg/cm[sup 2], respectively, and that the FOM values for LiAsF[sub 6]-EC/2MeTHF increased with increasing stack pressure up to at least 125 kg/cm[sup 2].

OSTI ID:
7039015
Journal Information:
Journal of the Electrochemical Society; (United States), Journal Name: Journal of the Electrochemical Society; (United States) Vol. 141:3; ISSN JESOAN; ISSN 0013-4651
Country of Publication:
United States
Language:
English