Effects of optimization of the single-walled carbon nanotube content in Silicon-Graphite anodes for Li-Ion batteries

초록

Silicon-graphite (Si/Gr)-blended anodes have emerged as promising candidates for next-generation lithium-ion batteries (LIBs) owing to their high capacity potential. However, achieving high rate capability and long-term cycling stability remains a major challenge. In this study, we investigated the role of the single-walled carbon nanotube (SWCNT) content (0.5 % and 1.0 %) in the optimization of the electrochemical performance of Si/Grblended electrodes. The Si/Gr-CNT 1 wt% electrode exhibited excellent rate capability, delivering 538.4 mAh/g at 2 C owing to the improved charge transfer kinetics facilitated by the high electrical conductivity of the SWCNT network. However, contrary to expectations, this high SWCNT content led to reduced long-term cycling stability. Through detailed electrochemical analyses, we identified that the increased specific surface area of the Si/Gr-CNT 1 wt% electrode promoted parasitic side reactions, ultimately accelerating electrode degradation. By contrast, the Si/Gr-CNT 0.5 wt% electrode demonstrated superior cycling performance, maintaining 70.5 % capacity retention after 100 cycles at 0.3 C, along with enhanced structural stability. These findings highlight the importance of balancing the SWCNT content to tailor the performance of Si/Gr-blended anodes according to application-specific requirements.

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