Fabrication and Performance Evaluation of Silicon Particles for Secondary Battery Cathode Materials from Waste Silicon Wafers

Silicon wafers are manufactured in the semiconductor and solar industries, but a significant amount is generated as waste. These wastes have relatively high purity and are valuable as a circular resource if appropriate utilization is found. In this study, we aimed to utilize waste wafers from the semiconductor process for the lithium-ion battery industry. Lithium-ion battery anode materials are mainly made of graphite, but silicon is increasingly being used to increase capacity and fast charging characteristics. In this study, metallic silicon, polysilicon, and recycled silicon were ground to form micro-sized particles and nanoparticles were prepared using a plasma process. The surface treatment was applied to improve the properties. Finally, it was manufactured into a coin cell and its properties were evaluated. The recycled silicon anode material prepared from the waste wafers showed better properties compared to the existing virgin material. In conclusion, recycled silicon is expected to be successfully applied to secondary batteries and be valuable as a recycled resource.