Boron-doped porous waste silicon/carbon composite with improved performance for lithium-ion batteries

With the rapid development of the photovoltaic (PV) industry, the amount of PV silicon (Si) produced by cutting is also increased. Therefore, recycling PV Si produced by PV cutting is critical. Herein, we used PV Si to design a kind of boron-doped porous silicon/carbon (B-Si/C) composites through acid etching and freeze-drying methods. The B-Si/C has a uniform size (25–35 nm), rich pores and good dispersibility. Porous Si doped with B can shorten the ion transmission distance. Simultaneously, the outer carbon layer of B-Si/C can relieve the volume expansion of the Si nanoparticles and prevent the Si nanoparticles from agglomerating during charge–discharge cycles. When applied as anodes for lithium-ion batteries (LIBs), the B-Si/C exhibits superior electrochemical performance with a commendable capacity of 1240 mA h g⁻¹ at 420 mA g⁻¹ after 100 cycles. It is very viable environmentally and economically to produce advanced high-capacity anode materials for LIBs using PV Si.