Lithium and Oxygen Co-Engineered Si-Rich SiOx for High-Performance Lithium-Ion Batteries

Silicon monoxide (SiO) is a promising alternative to graphite for lithium-ion battery anodes, but its low initial Coulombic efficiency (ICE) remains a challenge. While prelithiation improves ICE, it often reduces capacity due to lithium silicate formation. Our research addresses this by developing a prelithiated Si-rich SiO0.5 through high-energy mechanical milling, lithiation, and LiH addition. This material achieved a remarkable capacity of 2093 mAh g-1 and an ICE of 88.1%, outperforming both pristine and conventionally prelithiated SiO. Despite concerns about poor retention with increased Si content, the porous structure of Si and lithium silicate phases in our material alleviates expansion during cycling, maintaining stable capacity over 300 cycles. This advancement offers a promising route to practical SiO anodes for next-generation lithium-ion batteries.