多级碳复合的大尺寸硅颗粒在锂离子电池负极中的性能

Silicon-carbon composite materials within various carbon structures (SPU and SPU#PANI) were created using liquid phase wrapping and low-temperature pyrolysis, with large-size silicon particles (200—800 nm) from photovoltaic cell production waste as raw materials and water-based polyurethane (PU) and polyaniline (PANI) as carbon sources. The effects of carbon content, microstructure, and elemental doping on the electrochemical characteristics of SPU and SPU#PANI as anode materials for lithium-ion batteries were investigated. A low content of carbon composite in the SPU results in a high initial discharge capacity of up to 2193.6 mAh/g but poor charge and discharge cycle stability. However, the conductivity of SPU#PANI was increased after a secondary carbon composited. Additionally, it obtains a high discharge capacity (1488.8 mAh/g) as a result of the influence of porous carbon microstructure. The SPU#PANI's specific capacity was still over 756.8 mAh/g after 100 cycles, indicating good rate performance. The findings showed that the carbon with porous structure composite on the surface of large-size silicon particles serves not only a buffer for the expansion of the silicon in the process of charge and discharge but also a channel for lithium-ion transmission, significantly enhancing the electrochemical performance and stability of the silicon-based anode. The low-temperature pyrolysis technique used to composite multistage carbon on large-scale silicon particles provides a key reference for the industrialization technology development of silicon-based anode for lithium-ion batteries.