Crystallographic Engineering in Micron-Sized SiOx Anode Material Toward Stable High-Energy-Density Lithium-Ion Batteries

The SiOx anode exhibits a high specific capacity and commendable durability for lithium-ion batteries (LIBs). However, its practical application is hindered by significant volumetric fluctuations during lithiation/delithiation, alongside a metastable nature, which induces mechanical instability and irreversible lithium consumption, ultimately impairing long-term capacity retention in full-battery cell configurations. In this study, we present a phase-engineering approach designed to improve the structural stability of SiOx anodes for LIB applications. By incorporating lithium fluoride, amorphous SiOx undergoes partial transformation into a quartz-like phase, which enhances mechanical integrity and mitigates irreversible lithium loss. This modified anode demonstrates significantly improved stability and prolonged cycle lifespan. Through a combination of multiscale simulations and in situ characterizations, we elucidate the stabilization mechanisms conferred by the quartz phase, providing critical insights into the role of SiOx's crystal structure in influencing degradation pathways. This work introduces an accessible and efficient method for controlling the crystallinity of SiOx, offering a practical solution to enhance the durability of high-energy-density LIBs.