Comparison of commercial silicon-based anode materials for the design of a high-energy lithium-ion battery

초록

Silicon (Si) is considered a potential alternative anode for next-generation Li-ion batteries owing to its high theoretical capacity and abundance. However, the commercial use of Si anodes is hindered by their large volume expansion (similar to 300%). Numerous efforts have been made to address this issue. Among these efforts, Si-graphite co-utilization has attracted attention as a reasonable alternative for high-energy anodes. A comparative study of representative commercial Si-based materials, such as Si nanoparticles, Si suboxides, and Si-Graphite composites (SiGC), was conducted to characterize their overall performance in high-energy lithium-ion battery (LIB) design by incorporating conventional graphite. Nano-Si was found to exhibit poor electrochemical performance, with severe volume expansion during cycling. Si suboxide provided excellent cycling stability in a full-cell evaluation with stable volume variation after 50 cycles, but had a large irreversible capacity and remarkable volume expansion during the first cycle. SiGC displayed a good initial Coulombic efficiency and the lowest volume change in the first cycle owing to the uniformly distributed nano-Si layer on graphite; however, its long-term cycling stability was relatively poor. To complement each disadvantage of Si suboxide and SiGC, a new combination of these Si-based anodes was suggested and a reasonable improvement in overall battery performance was successfully achieved.

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