Functionalized CNTs Enhancing Conduction and Interfacial Stability via Multiple Mechanisms in Ni‐Rich Cathodes

Abstract Lithium‐ion batteries (LiBs) are pivotal for applications in electric vehicles, portable electronics, and energy storage systems, owing to their high energy density and long cycle life. Nevertheless, the intrinsically low electronic conductivity of Ni‐rich cathodes (e.g., NCM811) severely restricts charge transfer kinetics, thereby constraining battery performance. To address this critical issue, a composite conductive additive comprising functionalized carbon nanotubes (CNTs) and carbon black (CB) is designed to construct a 3D conductive network and facilitate lithium‐ion transport. Furthermore, the regulatory effects of CNTs' functionalized groups (─COOH, ─OH, ─NH ₂ ) on cathode‐electrolyte interface (CEI) formation kinetics, cathode structural stability, and long‐term cycling performance are elucidated. The results reveal that the steric hindrance and polarity of functional groups significantly influence both the construction of the conductive network and the formation and stability of the CEI layer. Among them, the optimized CB/CNT‐COOH electrode exhibits superior rate capability (53.1% capacity retention at 10C relative to 0.1C) and cycling stability (73.8% retention after 200 cycles at 1C), surpassing pristine CB and other functionalized CNTs. This work clarifies the mechanism of functional groups optimizing charge transport and interfacial stability, providing a scalable strategy to advance high‐energy Ni‐rich cathodes.