Flexible Porous Silicon/Carbon Fiber Anode for High−Performance Lithium−Ion Batteries

We demonstrate a cross-linked, 3D conductive network structure, porous silicon@carbon nanofiber (P-Si@CNF) anode by magnesium thermal reduction (MR) and the electrospinning methods. The P-Si thermally reduced from silica (SiO2) preserved the monodisperse spheric morphology which can effectively achieve good dispersion in the carbon matrix. The mesoporous structure of P-Si and internal nanopores can effectively relieve the volume expansion to ensure the structure integrity, and its high specific surface area enhances the multi-position electrical contact with the carbon material to improve the conductivity. Additionally, the electrospun CNFs exhibited 3D conductive frameworks that provide pathways for rapid electron/ion diffusion. Through the structural design, key basic scientific problems such as electron/ion transport and the process of lithiation/delithiation can be solved to enhance the cyclic stability. As expected, the P-Si@CNFs showed a high capacity of 907.3 mAh g-1 after 100 cycles at a current density of 100 mA g-1 and excellent cycling performance, with 625.6 mAh g-1 maintained even after 300 cycles. This work develops an alternative approach to solve the key problem of Si nanoparticles' uneven dispersion in a carbon matrix.