Effect of SWCNT/Super-P Hybrid Conductive Network Composition on Conductive Network Formation and Electrochemical Performance in Si/C Composite Negative Electrodes

Silicon (Si) is considered a promising next-generation negative electrode material for lithium-ion batteries (LIBs) owing to its high theoretical capacity (approximately 3580 mAh g⁻¹), which is significantly higher than that of conventional graphite. However, Si undergoes severe volume expansion (>300%) during repeated lithiation and delithiation processes, resulting in particle pulverization, loss of electrical contact, and unstable solid electrolyte interphase (SEI) formation. These structural and interfacial instabilities lead to rapid capacity degradation and poor cycling stability. In this work, single-walled carbon nanotubes (SWCNTs) were introduced as a conductive additive to improve the electrochemical stability of Si-based electrodes. Due to their high aspect ratio and structural flexibility, SWCNTs can form an interconnected conductive network within the electrode structure, which helps maintain electrical pathways and accommodate mechanical stress generated during repeated volume changes of Si particles. To systematically investigate the effect of conductive additive composition, Si/C composite electrodes were fabricated with varying SWCNT/Super-P hybrid conductive additive ratios (SWCNT content: 0, 0.2, 0.5, 0.7, and 1.0 wt%), while maintaining a constant total conductive additive content of 4 wt%. The electrochemical behavior of the electrodes was systematically evaluated through galvanostatic charge – discharge cycling, voltage profile analysis, and differential capacity analysis. The results suggest that the electrochemical behavior of Si-based electrodes is strongly influenced by hybrid conductive additive composition. These results demonstrate that optimization of the SWCNT/Super-P hybrid