Nano-silicon/graphite composites caged by mesophase pitch-derived carbon as anode materials for stable lithium storage

The development of silicon/graphite composites is a feasible solution for improving the short cycling life of Si-based anodes. However, unsatisfactory solid interfaces and structural integrity impede the achievement of the anticipated electrochemical performance. Herein, naphthalene-based mesophase pitch is used as the carbon precursor to wrap nano-Si/artificial graphite (AG) composites through an impregnation-carbonization route. Structural characterization revealed that the pyrolyzed carbon formed graphitic and porous carbon cages, which not only promoted the transport of charge carriers but also mitigated the expansion of Si particles. After 500 charge-discharge cycles at a high current density of 1000 mA g-1, the anode material with a Si/graphite/pitch mass ratio of 2:5:10 achieved a specific capacity of 432 mAh g-1 and a coulombic efficiency of 99.5%. Considering the facile manufacturing technique, good cycling stability, and rate capability, Si/graphite/C anode materials possess promising industrialization prospects for next-generation lithium-ion batteries.