Carbon Nanofiber Cages and Interface Engineering Stabilizing Silicon-Based Anode for High-Performance Lithium-Ion Batteries

Silicon (Si)-based anodes have emerged as a highly promising material for the next generation of lithium-ion batteries (LIBs) due to their numerous advantages. However, the practical application of Si-based anodes is currently hindered by various challenges, such as significant volume variation and limited electronic conductivity. Herein, silicon/carbon/carbon nanofiber (Si/C/CNF) composites are prepared by using micron Si as the silicon source, carbon dioxide (CO2) as the green carbon source, and Ni powder as the catalyst. The formation of CNFs originates from the Ni-catalyzed thermal reduction of CO2, while the released heat facilitates the formation of SiC and Ni3Si2 interfaces on the surface of Si, resulting in Si/C/CNF composites with a unique structure. The dual interface of SiC and Ni3Si2 can not only reduce the side reactions of Si but also effectively mitigate the volume expansion of Si. Meanwhile, the CNF cage grown in situ can improve the electrical conductivity of the composite and promote electron/ion transport. Consequently, the Si/C/CNF anode shows an impressive cycling stability and an excellent rate performance (1300 mA h g(-1) at 4 A g(-1)). The full cell constructed with the Si/C/CNF anode and the LiFePO4 cathode exhibits high capacity retention (95.8% capacity retention after 150 cycles at 0.2 C). This study provides a perspective for the preparation of next-generation Si-based anodes.