Construction of Air-Stable Pre-Lithiated SiO <sub>x</sub> Anodes for Next-Generation High-Energy-Density Lithium-Ion Batteries

Due to the high energy density and low production cost, silicon oxide (SiOx) is recognized as one of the most promising anode materials for lithium-ion batteries. However, the low initial Coulombic Efficiency and rapid capacity attenuation of SiOx anode severely restricted its commercial application. This work, for the first time, proposed a scalable strategy of pre-lithiation followed by a thermal passivation to improve the initial Coulombic Efficiency of SiOx anode, boosting the large-scale commercial applications of pre-lithiation strategy. Firstly, the hollow porous SiOx@C spheres (Hp-SiOx@C) with adjustable shell thickness were first designed using a self-transformation method, and then an air stable pre-lithiated Hp-SiOx@C (ASP-Hp-SiOx@C) anode was prepared through an electrochemical pre-lithiation followed by a thermal passivation strategy. ASP-Hp-SiOx@C anode delivered stable cycling performance, 1058.9 mAh g-1 with 89.8% capacity retention at 1.0 A g-1 after 1000 cycles, and high initial Coulombic Efficiency of 99.2% after being exposed to the atmosphere with 10% - 20% relative humidity for 48 h. In addition, this method of preparing ASP-Hp-SiOx@C anode could also be applied to transition metal oxide and tin-based oxide anodes.