Construction of stable SEI film on Si@C high-loading electrodes by dimethoxydimethylsilane electrolyte additives

Silicon (Si), with its high capacity and abundant resources, presents a huge application prospect for high-energy density lithium ion batteries. Unfortunately, continuous interface reactions induced by huge volumetric changes limit its wide application. Herein, we employ dimethoxydimethylsilane (DMDOS) as an additive to enhance the electrochemical performances in LiNi0.8Co0.15Al0.05O2(NCA)/Si@C pouch cell with high-loading electrodes. DMDOS can be decomposed preferentially and then create a dense layer of Si–O-Si cross-polymerized network on the electrode surface, mitigating continuous interface reactions of the electrolyte during long-term cycling. As a consequence, the pouch battery with 1% DMDOS renders an outstanding capacity retention of 85.5% over 100 cycles, whereas the pouch battery without DMDOS only shows a low capacity retention of 77.7%. Hence, DMDOS is an effective additive candidate for the development of high-energy density lithium ion batteries.