Constructing Functional Lithium-Ion Transport Interfaces by In-Situ Growth and Transformation on Chemical Vapor Deposition-Derived Silicon–Carbon Anode Materials

Silicon–carbon materials fabricated through the chemical vapor deposition technique have achieved remarkable progress in specific capacity, initial Coulombic efficiency (ICE), and volume expansion control, making them currently the most promising Si-based materials for the next-generation high-performance lithium-ion batteries (LIBs). However, the intrinsic discontinuous distribution of nanosized Si within a highly porous carbon framework tends to impede Li+ transport, thereby limiting its fast-charging capability. Herein, a novel silicon–carbon anode material (SSC@LSO) with a continuous and accelerated Li+ transport interface was developed. This material was synthesized by depositing nanosized Si into porous carbon via silane pyrolysis, followed by transforming the surface Si layer into a LixSiOy layer through surface oxidation and lithiation. The LixSiOy layer could penetrate into SSC@LSO, forming continuous Li+ transport channels, mitigating volume expansion, and minimizing side reactions with the electrolyte. As a result, SSC@LSO exhibits significantly improved rate capability and cycling stability, maintaining a high specific capacity (1959.7 mA h g–1) and ICE (91.9%). An Ah-level pouch cell using SSC@LSO demonstrates excellent cycling stability (91.7% at 25 °C and 83.7% at 45 °C capacity retention after 1000 cycles) and high-rate performance (86.9% capacity utilization rate under 5C), highlighting its high practical value for high-performance LIBs.