Protective electrode/electrolyte interphases for high energy lithium-ion batteries with p-toluenesulfonyl fluoride electrolyte additive

High energy density lithium-ion batteries using Ni-rich cathode (such as LiNi0.6Co0.2Mn0.2O2) suffer from severe capacity decay. P-toluenesulfonyl fluoride (pTSF) has been investigated as a novel film-forming electrolyte additive to enhance the cycling performances of graphite/LiNi0.6Co0.2Mn0.2O2 pouch cell. In comparison with the baseline electrolyte, a small dose of pTSF can significantly improve the cyclic stability of the cell. Theoretical calculations together with experimental results indicate that pTSF would be oxidized and reduced to construct protective interphase film on the surfaces of LiNi0.6Co0.2 Mn0.2O2 cathode and graphite anode, respectively. These S-containing surface films derived from pTSF effectively mitigate the decomposition of electrolyte, reduce the interphasial impedance, as well as prevent the dissolution of transition metal ions from Ni-rich cathode upon cycling at high voltage. This finding is beneficial for the practical application of high energy density graphite/ LiNi0.6Co0.2Mn0.2O2 cells. (c) 2020 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.

Automated summary

The novel electrolyte additive p-toluenesulfonyl fluoride (pTSF) has been found to improve the cycling performance of Ni-rich cathode lithium batteries by constructing protective interphase films, reducing interphasial impedance, and preventing metal ion dissolution. This finding is beneficial for the practical application of high energy density lithium batteries.