The caterpillar-defective CNTs for efficient electronic conduction and ionic transport as electrode materials for supercapacitor

Tuning the configuration of carbon nanotubes (CNTs) is an advanced strategy to improve the supercapacitor performance. Herein, this work successfully synthesizes caterpillar-defective carbon nanotubes (C-CNTs) encapsulating NiCo selenide nanoparticles (NiCo-Se NPs) using a tapered fluidized bed reactor (TFBR). Theoretical DFT calculations reveal that the defective structure of C-CNTs drastically reduces the energy gap compared to pristine CNTs, which is predicted to improve electronic conductivity. In addition, the calculations also indicate enhanced -OH adsorption affinity with larger binding energy for C-CNTs, which is proposed to accelerate electrochemical kinetics and increase charge-storage capacity. Electrochemical characterizations show that the optimized C-CNTs/NiCo-Se electrode demonstrates an exceptional specific capacity of 194.57 mAh g −1 at 1 A g −1 and a high energy density of 58.8 Wh kg −1 in an assembled asymmetric supercapacitor (ASC). The device retains 84.04% capacity after 10,000 cycles. Notably, the performance enhancement originates from the comprehensive structural advantages induced by the unique TFBR reactor architecture and optimized synthetic atmosphere, including CNT structural defects, uniform NiCo-Se dispersion, and efficient carbon growth. More importantly, this work pioneers a new avenue for the synthesis and structural modulation of advanced CNT-based materials, offering transformative potential for advancing high-performance energy storage devices.