Scalable synthesis of high-performance Si/CNTs/C anodes for lithium-ion batteries based on recycling of silicon cutting waste

Si is expected to replace graphite anode materials in the next generation of high-energy-density lithium-ion batteries due to its high specific capacity and abundant resources. However, the poor electrical conductivity and the huge volume expansion during the lithiation and delithiation process hindering its further commercial application. In this work, silicon cutting waste(SCW)generated in the photovoltaic industry was recycled as raw material, and a slurry containing Si after sanding(S-Si) was obtained in the sanding machine, carbon nanotubes (CNTs) and polyvinylpyrrolidone (PVP) were added to the slurry, mixed homogeneously and then spray-dried and granulated, after high-temperature carbonization, Si/CNTs/C composite with high vibrational density, homogeneous particle size and excellent electrochemistry were obtained. The nano-sized Si can accommodate the volume expansion during the cycling process, and the CNTs are interspersed in the composite to construct a conductive network, thus enhancing the electronic conductivity of the composite. The assynthesized Si/CNTs/C composite exhibited a residual capacity of more than 1000 mAh.g(-1) after 500 cycles at a current of 1 A.g(-1) and a capacity of 878 mAh.g(-1) even at 10 A.g(-1). Notably, full lithium-ion batteries with a Si/CNTs/C anode and LiFePO4 cathode delivered a stable capacity of 130 mAh.g(-1) with an ICE of 88.1 %. Our work provides reference solutions for the recycling of waste materials in the photovoltaic industry as well as the preparation of low-cost, high-performance Si/C anodes for lithium-ion batteries.