High-performance graphite||Li4Ti5O12 dual-ion full batteries enabled by in-situ formation of LiF-rich solid electrolyte interphase on Li4Ti5O12 anode

Abstract

Dual-ion batteries (DIBs), well-known for the high-rate capability of the graphite cathode, urgently need a suitable anode material to realize their high power density in practical applications. In that respect, Li4Ti5O12 (LTO), which can be cycled at high rates for thousands of cycles, can be a good candidate. However, a facile method to stabilize the graphite||LTO full cells is necessary. Herein, we introduce LiDFOB additive into the electrolyte of graphite||LTO cells, which drastically improves the cycling performance and reduces self-discharge of the DIBs. Specifically, by adding 1.0 wt% LiDFOB to 2 M LiPF6 in fluorinated ethyl methyl carbonate, graphite||LTO DIBs can maintain stable charge-discharge for over 8000 cycles at 20 C. Characterizations indicate that LiDFOB forms a robust LiF-rich solid electrolyte interphase (SEI) on the LTO anode to suppress side reactions such as electrolyte decomposition and gas generation.