Phase Control of Lithium Silicates for Process‐Friendly Prelithiated SiO Anode Materials**

Abstract

AbstractA low‐level metallic lithium thermal prelithiation strategy has been developed for boosting the performance of SiO anode materials with aqueous slurry processability. This facile prelithiation method can alter the phase and crystalline size of lithium silicates by controlling the parameters such as lithium contents and processing temperatures. The prelithiated graphene‐SiO composite anode material thus obtained under the optimized condition offers a high reversible capacity of 1062 mAh g−1 and the initial Coulombic efficiency of 80.8 %. Additionally, both the cycle life and cycling Coulombic efficiency are extremely stable, preserving over 90.3 % of the capacity after 200 cycles and more than 99.7 % of the efficiency on average during cycling. The significantly enhanced battery performance of the prelithiated SiO anode materials is owing to the size control of crystal silicon and Li2SiO3 phases. The existence of Li2Si2O5 and suppression of Li4SiO4 formation also guarantee homogeneous prelithiation results. This facile low‐level prelithiation approach is remarkably effective to improve the initial Coulombic efficiency for commercial SiO anode materials and simultaneously maintain superior reversible capacity, cycle life, cycling efficiency, and aqueous slurry processability.