Calcium silicate composited nano-Si anode with low expansion and high performance for lithium-ion batteries

SiO is a promising anode material for next-generation lithium-ion batteries(LIBs)with high-energy density.However,the passivation of silicon oxide in SiO remains challenging to reduce its irreversible reactions and volume expansion during cycling.In this work,a scalable approach is proposed to synthesize calcium silicate/nanosilicon composites(pSi@CaO)by transforming the SiO2 in disproportionate SiO into calcium sili-cate at 1000℃.The bulk-distributed calcium silicate in pSi@CaO can effectively inhibit nanosilicon expan-sion and enhance ionic transfer.The optimized pSi@20%CaO anode demonstrates a low electrode expan-sion of 12.3%upon lithiation and 7.6%upon lithiation after 50 cycles.It also exhibits excellent electrochemi-cal stability,delivering a specific capacity of 808 mAh g^(−1)at 50 mA g^(−1)with an initial Columbic efficiency of 72%and maintaining 82%capacity after 500 cycles at 1 A g^(−1).The feasible CaO passivation strategy proposed in this work is expected to promote practical applications of Si-based anodes in high-performance LIBs.