Construction of a Stable LiNi0.8Co0.1Mn0.1O2 (NCM811) Cathode Interface by a Multifunctional Organosilicon Electrolyte Additive

It is still a big challenge to stabilize Ni-rich cathode interface at high current rate and a long-term cycle in the present Li-ion battery for electric vehicles. In this work, N,O-bis(trimethylsilyl)acetamide (BSA) is utilized as a multifunctional electrolyte additive to stabilize LiNi0.8Co0.1Mn0.1O2 cathode interface and enhance its electrochemical performances. After 200 cycles, the LiNi0.8Co0.1Mn0.1O2/Li cell at 1C rate with 0.5% BSA shows enhanced capacity retention of 86%, while only 69.4% with the baseline electrolyte. When the discharge rate is increased to 2C, the LiNi0.8Co0.1Mn0.1O2/Li cell with BSA additive shows enhanced capacity retention of 72.6% after 400 cycles, while the counterpart is only 49.5%. The experimental results show that HF, H2O can be scavenged by BSA and the hydrolysis of LiPF6 is reduced. Moreover, BSA additive can be preferentially oxidized during the charging process and form a robust, uniform electrode/electrolyte interface film on NCM811 cathode surface. Consequently, a ...