Deciphering the Interactions of Carbon Nanotubes and Super P with Silicon and Graphite Active Materials in Silicon‐Graphite Negative Electrode‐Based Lithium‐Ion Batteries

Abstract In high‐capacity Silicon (Si)‐based negative electrodes for Lithium‐Ion Batteries (LIBs), conductive additives play a pivotal role for preserving electrical conductivity and electrode integrity, boosting the electrochemical performance. This study presents how defect‐mediated Multi‐walled Carbon Nanotubes (MWCNTs) impact battery performance when employed as conductive additive material in both high‐capacity Si and low‐capacity graphite (Gr) electrodes. For benchmarking, state‐of‐the‐art carbon black (Super P) is used. Half‐cell test results of MWCNTs‐based Si‐rich Si/Gr (60/28) blended electrodes exhibit a specific discharge capacity of 534.2 ± 21.1 mAh g −1 with a capacity retention of 73.3% at 100th cycle, surpassing Super P‐based counterparts, which achieve only 436.1 ± 16.3 mAh g −1 and 61.7% retention at the same cycle. However, for Gr‐rich Si/Gr (20/68) blended electrodes, the discrepancies in performance and capacity retention between both conductive additives is less significant than in the Si‐rich Si/Gr electrode system. Imaging and spectroscopic analyses reveal that the differences in performance originate from the distinctive interactions between the surface functional groups of the conductive additives and those of the active materials. Overall, the findings highlight the critical role of defect‐mediated interaction chemistry in MWCNTs in boosting electrochemical performance, offering valuable insights for the design of next‐generation LIB electrodes.