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Title: A study of perfluorocarboxylate ester solvents for lithium ion battery electrolytes

We prepared several high-purity methyl perfluorocarboxylates (>99.5% purity by mole) and investigated as potential fluorine-rich electrolyte solvents in Li-ion batteries. The most conductive electrolyte, 0.1 M lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) in dimethyl perfluoroglutarate (PF5M2) (ionic conductivity 1.87 10-2 mS cm-1), is investigated in Si thin-film half-cells. The solid-electrolyteinterphase (SEI) formed by the PF5M2 electrolyte is composed of similar organic and inorganic moieties and at comparable concentrations as those formed by ethylene carbonate/dimethyl carbonate electrolytes containing LiPF6 and LiTFSI salts. But, the SEI formed by the PF5M2 electrolyte undergoes reversible electrochemical defluorination, contributing to the reversible capacity of the cell and compensating in part for capacity fade in the Si electrode. These electrolytes, though far from ideal, provide an opportunity to further develop predictions of suitable fluorinated molecules for use in battery solvents.
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [4] ;  [2]
  1. Missouri Univ. of Science and Technology, Rolla, MO (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  3. Missouri Univ. of Science and Technology, Rolla, MO (United States)
  4. Univ. of Missouri, Columbia, MO (United States)
Publication Date:
OSTI Identifier:
1265852
Grant/Contract Number:
AC05-00OR22725; DGE-1069091; AC05-06OR23100
Type:
Accepted Manuscript
Journal Name:
Journal of Power Sources
Additional Journal Information:
Journal Volume: 299; Journal Issue: C; Journal ID: ISSN 0378-7753
Publisher:
Elsevier
Research Org:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); National Science Foundation (NSF)
Country of Publication:
United States
Language:
English
Subject:
25 ENERGY STORAGE SEI; LiTFSI; silicon thin-film; fluorinated electrolyte