A low-cost preparation of Si@C composite anode from Si photovoltaic waste

Abstract

Silicon materials are recognized as one of the most attractive anode materials in Li-ion batteries (LIBs) due to their ultrahigh capacity. However, there are still challenges to fabricate silicon-based anodes with a sustainable, scalable and cost-effective method. In this work, nanoscale Si was synthesized using the wafer slicing wastes from photovoltaic (PV) industry via a scalable and facile fabrication approach. After purification and sand milling, the obtained Si of 100-200 nm delivers a high discharge capacity of 2554 mAh g-1. To address the potential application of the nanoscale Si in practical LIBs, a silicon/carbon composite (Si@C-G) was made, which is composed of the nanoscale Si, artificial graphite, graphene and pyrolytic carbon. The Si@C-G composite anode could yield a stable capacity of around 400 mAh g-1, and a high retention rate of 91% can be achieved after 100 cycles, where the introduced graphene provide a better conducting/buffering network. Our work shows the waste Si from PV industry can be recycled and reused in LIBs industry.