Dimethoxydiphenylsilane (DDS) as an Electrolyte Additive for High Voltage Li-ion Batteries

抄録

The performance of the Li/LiNi_0.5Mn_1.5O₄ cells cycled to 5.0 V (vs. Li/Li⁺) using 1.0 M LiPF₆-EC/DMC (1/1, v/v) with and without dimethoxydiphenylsilane (DDS) at 25°C has been investigated. Cells with 1% DDS added deliver slightly lower initial discharge capacity than the cells with baseline electrolyte, 115.3 vs. 120.9 mAh g⁻¹. Electrochemical methods and ex-situ analytical techniques, including TGA and SEM, are employed to conduct the interfacial chemistry of LiNi_0.5Mn_1.5O₄/electrolyte to better understand the improved electrochemical performances of the cells with introduction of DDS. The results indicate that DDS can be electro-oxidized and participates in the formation of the surface layer on cathode electrode, which prevents electrolyte from further decomposition and promotes Li⁺ conduction of the cathode/electrolyte interphase, thus improves the electrochemical performances of Li/LiNi_0.5Mn_1.5O₄ cells.