Rational Design of Cu3Si Interphase for 3D Micron-Sized SiOC-based Anode to Enable Long-Term Cycling of Lithium-Ion Battery

The low effective capacity, inferior initial Coulombic efficiency, and unstable solid electrolyte interface (SEI) of silicon oxycarbide (SiOC) materials in lithium-ion batteries (LIBs) pose significant challenges for the widespread application. Herein, to circumvent these issues, a micron-sized SiOC-based anode with 3D structure is constructed by Si and Cu co-doping using solvent-free ball milling for high-performance LIBs. The Cu 3 Si alloy is formed in situ as an intermediate that is anchored to the surface of Si within the SiOC matrix. The unique 3D SiOC-based anode with Cu 3 Si interphase provides fast electron conductivity and high mechanical strength, while facilitating the formation of a robust and LiF-rich SEI. Specifically, the SiOC-based anode delivers excellent cyclic stability and rate capability (750.0 mAh g −1 for 1000 cycles at 1 A g −1 ). Notably, the full cells equipped with an NCM811 cathode maintain this cyclic stability, achieving a 93.0% capacity retention after 150 cycles. This work provides insights into the rational fabrication of a 3D micron-sized SiOC-based anode with an in situ generated Cu 3 Si interphase for advanced LIBs and beyond.