Carbon nanotubes-enhanced lithium storage capacity of recovered silicon/carbon anodes produced from solar-grade silicon kerf scrap

Abstract Recovered solar-grade silicon kerf scrap is touted as an ideal silicon source for Si-based anodes in advanced lithium-ion batteries (LIBs) whose development is always troubled by the volume expansion and low conductivity. Here, an effective approach for carbon nanotubes (CNTs) enhanced recovered silicon/carbon anodes encapsulated by polymethyl methacrylate (PMMA)-derived carbon coating (Si/CNTs@PMMA-C) is described. The Si/CNTs@PMMA-C anode presents an impressive Li ion storage capacity and long cycle lifespans, delivering a high initial discharge capacity of 3732.7 mAhg−1 and initial coulombic efficiency of 78.2% at 200 mAg−1 with a reversible capacity retention of 1024.8 mAhg−1 after 200th cycle. Moreover, full-cells composed of Si/CNTs@PMMA-C anodes and commercial LiCoO2 cathodes display a good electrochemical performance and high energy density. These excellent electrochemical properties boil down to the synergistic effect of PMMA-derived carbon shell and high-purity recovered silicon; meanwhile, CNTs can further support volume expansion tolerance and electrical conductivity. This effective method can provide a broader practical application prospect for the silicon/carbon composite anodes based on low-cost recovered solar-grade silicon kerf scrap with enhanced electrochemical performance in advanced LIBs.