LiPO2F2 as a LiPF6 Stablizer Additive to Improve the high- temperature Performance of the NCM811/SiOx@C Battery

Wenfeng Song, School of Metallurgy and Environment, Central South University, Changsha Hunan 410083, China
2019 International Journal of Electrochemical Science  
Fluoroethylene Carbonate (FEC) is an indispensable additive to improve the cycle stability of silicon cathode, but the incompatibility between FEC and LiPF6 seriously damages the high temperature performance of NCM811/SiOx@C. In this paper, the LiPO2F2, tris(trimethylsilyl) borate (TMSB) and tris(trimethylsilyl) phosphate (TMSP) were added as stabilizer to increase the compatibility between LiPF6 and FEC at elevated temperatures. The visual experiments show that the traditional LiPF6 stablizer
more » ... al LiPF6 stablizer additive, such as (TMSB) and (TMSP) additive, would accelerate the decomposition of LiPF6 when FEC is present in the electrolyte solution. However, the introduction of LiPO2F2 additive can effectively inhibits the decomposition of LiPF6, then obviously inhibits the side reactions and decrease the selfdischarge of the NCM811/SiOx@C pouch cells under high temperature storage conditions. The hightemperature (45 o C) cycling performance of pouch cells with LiPO2F2 additive is 90.3% for 200 cycles and the swelling ratio is only 1.96% after storage at 55 o C for 7days, which are all far superior to the contrast sample.
doi:10.20964/2019.09.55 fatcat:uwqcddkq3ng2hnljgstzd3xed4