Porous dual carbon framework coated silicon nanoparticles for high-performance lithium-ion batteries

Silicon-based materials are promising materials for lithium-ion battery anodes with high specific capacities. However, the volume expansion of silicon during charging and discharging leads to the destruction of the material structure, increased mechanical stress, solid electrolyte interface (SEI) film rupture, and rapid capacity decay. Here, a composite material with a porous double-layer carbon structure of coated silicon nanoparticles (Si@C@PMP) is fabricated by sequentially coating the surface of silicon nanoparticles with resorcinol-formaldehyde resin and mesophase pitch-ordered soft carbon. The porous mesophase pitch coating skeleton is formed by the action of the templating agent calcium carbonate. The cross-linked double-layer carbon structure could accommodate the volume expansion of silicon and improve the electrical conductivity and structural stability of the electrode. The microstructure and electrochemical analysis reveal that Si@C@PMP possesses excellent structural and cyclic stability. The results show that the anode material has a capacity of 774 mA h g −1 after 300 cycles at 0. 2 A g −1 . Even after 500 cycles at 1 A g −1 , it still has a good capacity of 646 mA h g −1 with only 13.6% electrode thickness expansion. This method may provide an idea for preparing stable silicon/carbon composites.