ZIF-67-derived porous nitrogen-doped carbon shell encapsulates photovoltaic silicon cutting waste as anode in high-performance lithium-ion batteries

Abstract

The rapid development of the photovoltaic industry generates nearly 35 wt% micron-scale silicon powder waste in the form of a paste. This study reports the in-situ synthesis of ZIF-67 on the surface of low-cost silicon cutting waste. Submicron-scale porous cage-like silicon-based composites were obtained by carbonization. This hollow framework structure facilitated the large volume expansion/contraction of Si during charging/discharging. The porous nitrogen-doped carbon layer not only yielded rapid transport channels for Li+ and electrons but also improved the electrical conductivity of the material. In addition, the excellent pseudocapacitive performance of the Si@NC-ZIF composite also enhanced lithium storage. The composite exhibited excellent capacity retention of 1623.05 mAh/g after 100 cycles at 200 mA g−1, with the retention rate reaching 86.29 %. When the current was switched from 2000 to 100 mA g−1, the discharge capacity recovered to 1453.35 mAh/g, showing excellent rate performance. This study provides a new approach for the recycling and value-added utilization of photovoltaic silicon cutting waste in lithium-ion battery anodes.