Lithium and oxygen engineered SiO0.5 materials for high performance lithium storage materials

Abstract

Silicon monoxide (SiO) is one of the most promising post-graphite anode materials for lithium-ion batteries. Prelithiation of SiO has been proposed as a potential method to improve its initial coulombic efficiency (ICE), which is a persistent challenge for SiO. However, pre-lithiation can decrease the capacity of SiO due to the formation of lithium silicate phases. To address this issue, we developed a strategy to improve the ICE and reversible capacity of SiO through lithium and oxygen engineering. Prelithiated Si-enriched SiO0.5 prepared by high-energy mechanical milling of Si and SiO with lithiation followed by LiH treatment, exhibited a capacity of 2093 mA h g-1 with an ICE of 88.1%, significantly surpassing the performance of both pristine and prelithiated SiO. While increasing the Si content may typically result in poor capacity retention, the unique porous structure formed by the Si and lithium silicate phases in this study mitigated this effect, ensuring capacity retention over 300 cycles by alleviating the expansion of Si during the lithiation/delithiation process.