Synergistic regulation of polyacrylonitrile derived N-enriched carbon and spent graphite on nano‑silicon anode for lithium-ion batteries

Lithium-ion batteries are currently widely used in electric vehicles, portable electronic products, and large capacity energy storage equipment. Therefore, the number of spent lithium-ion batteries are also increasing year by year. After processing, the spent graphite (SGr) in spent lithium-ion batteries can not only alleviate the large demand for graphite in the market, but also be used as raw materials for high value-added products. In this work, the SGr is combine with silicon nanoparticles (SiNPS) by solvothermal-exfoliation method to prepare the Si@CPAN/SGr composite anode material. In the three-dimensional (3D) “double‑carbon” structure of Si@CPAN/SGr composite anode, the successful embedding of SiNPS into the layered structure of SGr will effectively alleviate the stress generated by SiNPS during the cycling process. At the same time, the doping of N element can enhance the interaction between active sites and lithium-ions (Li⁺), which is beneficial to the adsorption and storage of Li⁺ by Si@CPAN/SGr composite anode. The discharge specific capacity of Si@CPAN/SGr composite anode is 897.8 mAh g⁻¹ after 100 cycles at 0.5 A g⁻¹. Therefore, the SGr is used to prepare the Si@CPAN/SGr composite anode, which can provide a new idea for the recovery and high-value utilization of the SGr.