Reviving of silicon waste with N-doped carbon core-shell structure prepared by vapor deposition polymerization of polypyrrole applied in lithium-ion battery

Abstract

Lithium-ion battery is widely attracted in energy storage system owing to the high energy density and low cost. Silicon (Si) is regarded as the high capacity anode materials for replacing graphite to enhance the battery's energy density. However, the rapid fading during the charging and discharging process causes the battery system's poor retention. In this study, the waste Si from the photovoltaic industry is reused as anode materials. Furthermore, polypyrrole's vapor deposition polymerization is considered the N-doped carbon source, enhancing the electrochemical performance. The vapor deposition method offers a homogeneous coating solution, improving the material conductivity, and reducing the charge transfer resistance. In the electrochemical test, the Si/N-doped carbon sample demonstrates 3353mAh/g capacity at the current density of 0.5A/g in the first cycle. After 100 cycles, the sample reveals 787mAh/g, which is much higher than that without N-doped carbon coating (about 620mAh/g higher than waste-Si). Moreover, it also displays high capability in high current rate charging-discharging. Overall, N-doped carbon coating from vapor deposition polymerization is a facile method to decrease the Li-ion transport energy barrier and improve the electrochemical performance of waste Si for next-generation lithium-ion batteries.