LiF-Induced Formation of Quartz Nanodomains in Micron-Sized SiO_<i>x</i> Anodes for Durable Lithium-Ion Batteries

Silicon oxide (SiOx) anodes are promising for next-generation high-energy-density lithium-ion batteries. However, their application faces critical challenges of low initial Coulombic efficiency (ICE) and structural instability caused by drastic volume changes (>300%) during cycling. Here, we report a crystalline regulation strategy through LiF incorporation during deep disproportionation of SiOx, enabling in situ crystallization of a quartz phase within the amorphous SiO2 (a-SiO2) matrix. The LiF-mediated process simultaneously creates quartz nanodomains and redistributes Si nanodomains, optimizing the Si–O coordination. The as-modified SiOx anode achieves an ICE exceeding 80% and retains 38% higher capacity than pristine SiOx after 100 cycles. Postcycling analyses confirm the inert quartz phase serves as a mechanical anchor, stabilizing micrometer-sized particles by buffering volume variations and suppressing crack propagation. After pairing the SiOx/C anode with graphite, the full-battery cells demonstrate a notable enhancement in capacity retention. This approach combines low-temperature synthesis (<1000 °C), reduced energy consumption, and high yield, thereby addressing the promise of industrial scalability. The synergistic integration of a crystalline quartz phase (inert stabilizer) and active Si domains establishes a generalizable design principle for high-capacity electrode materials requiring balanced structural integrity and electrochemical activity.