Growth of High Density Single‐Walled Carbon Nanotubes on Hydroxyl‐Rich Silicon Anodes for Enhanced Lithium Storage

ABSTRACT Incorporating carbon nanotubes (CNTs) into silicon (Si) anodes significantly improves cycling stability. Compared to multi‐walled CNTs, single‐walled CNTs (SWNTs) provide greater flexibility, stronger van der Waals interactions, and superior interfacial contact with Si, ensuring effective electrical connectivity within the electrodes during long‐term cycling. Direct growth of SWNTs onto Si anodes via chemical vapor deposition is a promising strategy; however, their density is limited by low metal loading and the presence of large and inactive catalyst particles. Here, we employ an air plasma treatment to achieve a hydroxyl‐rich Si surface, promoting the metal catalysts adsorption and enabling high‐density SWNT growth. The abundant hydroxyl groups act as anchoring sites for ruthenium species, suppressing their possible aggregation. Consequently, an interconnected SWNT network forms on the Si anodes, improving electronic/ionic conductivity and mitigating volume expansion. The composite exhibits higher initial Coulombic efficiency and excellent cycling stability, while the assembled pouch full cell demonstrates practical flexibility. This study highlights the critical role of support surface properties in catalyst performance for SWNT synthesis and offers a viable approach to high‐performance Si anodes.