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

Abstract

The SiO_x 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 SiO_x anodes for LIB applications. By incorporating lithium fluoride, amorphous SiO_x 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 SiO_x's crystal structure in influencing degradation pathways. This work introduces an accessible and efficient method for controlling the crystallinity of SiO_x, offering a practical solution to enhance the durability of high-energy-density LIBs.