Enhancing Interfacial Interactions Through Microwave-Irradiated Reduction for the Recycling of Photovoltaic Silicon Waste for Lithium Storage

Abstract

The application of micro-nano size photovoltaic waste silicon (wSi) as an anode material for lithium-ion battery holds significant practical potential; However, it faces a series of challenges related to the volume expansion of Si during cycling. In this study, a simple, efficient, and eco-friendly microwave method is proposed for the rapid preparation of graphene-coated silicon materials (wSi@rGO) in just a few seconds, in which graphene as the stable interface mitigates structural failure caused by significant volume expansion, enhances electron and ion conductivity, inhibits undesirable side reactions between silicon and electrolyte, and promotes the stability of solid electrolyte interface (SEI). Importantly, the instantaneous high temperature generated by microwaves facilitates the formation of interfacial SiC chemical bonds, which strengthen the interaction between Si and graphene, thereby reducing Si delamination. The wSi@rGO anode exhibits remarkable cycling stability, maintaining a specific capacity of 1100 mA h g⁻¹ over 250 cycles. Furthermore, the assembled wSi@rGO//LiFePO₄ full battery demonstrates robust performance, retaining a stable capacity of 150 mA h g⁻¹ after 80 cycles at 0.5 C. This research not only demonstrates a straightforward and efficient microwave technique for synthesizing wSi@rGO anode materials, but also offers an environmentally friendly and economical pathway for recycling photovoltaic waste silicon, contributing positively to carbon peaking and carbon neutrality.