Stabilizing Micro‐Sized Silicon Oxides by Durable Hydrogen Chemistry

Micro-sized silicon oxide (µSiO_x) is considered one of the most promising anodes for commercial high-energy Li batteries owing to its low cost and high capacity. However, due to the instability of its solid electrolyte interphase (SEI), irreversible consumption of active lithium ions and continuous decomposition of the electrolyte occur, making long-term stability of µSiO_x a significant challenge. Herein, we effectively enhance the stability of the SEI on the surface of the µSiO_x anode through the dual functionality of hydrogen chemistry, namely interface regulation and atmospheric protection. With the assistance of the highly reversible hydrogen evolution and oxidation redox reactions, the discharge capacity of the µSiO_x anode can reach ∼1568 mAh g^-1 at 1 C when the charge capacity is 1600 mAh g^-1. Meanwhile, the µSiO_x anode can stably cycle for 2000 h with a Coulombic efficiency of ∼98% at a charge capacity of 700 mAh g^-1. Even at a high areal capacity of 3 mAh cm^-2, the µSiO_x anode can still cycle 600 h with the discharge capacity remaining ∼2.93 mAh cm^-2 (∼726 mAh g^-1). This study provides a proof-of-concept stabilization strategy for µSiO_x under high-capacity conditions, bringing this challenging anode material one step closer to practical applications.