1. Improving the performances of low concentration electrolytes via dual interfacial modification of the fluoroethylene carbonate solvent and lithium difluoro(oxalato)borate additive.
- Author
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Quan, Yin, Gao, Cankun, Wu, Shumin, Zhao, Dongni, Wang, Jie, Li, Chunlei, and Li, Shiyou
- Subjects
FLUOROETHYLENE ,ELECTROLYTES ,DIFFUSION barriers ,BORATES ,LITHIUM ions ,LITHIUM fluoride - Abstract
The high price of lithium salts hinders the sustainable development of high concentration electrolytes, while the poor electrochemical performance limits the large-scale application of low concentration electrolytes. Herein, the electrochemical performance of a low concentration electrolyte is improved via dual interfacial modification of the fluoroethylene carbonate (FEC) solvent and the lithium difluoro(oxalato)borate (LiODFB) additive. LiODFB is preferentially oxidized via a ring-opening path to generate a lithium fluoride (LiF)-rich inner layer on the surface of a ferrous lithium phosphate cathode, and then a large amount of C–F polycarbonate oligomers is generated in the outer layer via a reaction between LiODFB and FEC. LiF has a large bandgap and a low lithium ion (Li
+ ) diffusion barrier, and the electronegative C–F groups provide the lithiophilic sites to reduce the interaction between Li+ and solvents, resulting in a repulsive force towards the C=O dipole of the carbonate ester solvent to improve the oxidation stability of the electrolyte. The clever design of the multi-layer cathode electrolyte interphase suppresses the excessive decomposition of the electrolyte, improves the diffusion of Li+ , and enables much-improved cycling stability of the cathodes. This work gives a fruitful insight into the key role of cathode electrolyte interphase components in Li+ diffusion and improves the performance of low-concentration electrolytes. [ABSTRACT FROM AUTHOR]- Published
- 2022
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