Abstract:

Silicon-carbon (Si-C) anode materials have garnered substantial attention in lithium (Li)‍-ion battery development because of their high Li storage capacity and various advantages. Despite these merits, practical challenges, such as poor conductivity, substantial volume expansion, and inadequate interface compatibility, persist. This study initiates from the nano treatment of micro Si waste derived from solar cells, achieving scalable production of silicon nanoparticles with particle sizes around 300 nm by optimizing the sanding experimental parameters. Moreover, copper (Cu) nanoparticle-modified Si-C nanofiber composites (Cu-Si@CNFs) were prepared using the electrowinning method, where silicon and Cu nanoparticles were either embedded or attached to the CNFs. A comprehensive investigation of the electrochemical Li storage performance revealed that the composite, with CNFs as the matrix and supplemented by Cu nanoparticle modification, can establish a highly conductive grid. Effectively enhancing the conductance ability of composite materials, this approach overcomes the challenges associated with severe volume expansion and poor conductivity of silicon materials. The resulting material demonstrates substantially improved electrochemical Li storage performance. In particular, the optimized Cu-Si@CNF anode structure maintains a high reversible capacity of 765.9 mAh/g after 550 cycles at a high current density of 1.0 A/g. Consequently, this study provides valuable insights for the scalable preparation of silicon nanomaterials and Si-C composite anodes.

Key words: lithium-ion batteries, scalable fabrication of nano-silicon, silicon-carbon anodes, performance modulation, lithium storage capabilities