Alkali-Induced Porous MXene/Carbon Nanotube-Based Film Electrodes for Supercapacitors

MXenes have emerged as promising electrode materials for supercapacitors based on their metallic conductivity, good hydrophilicity, rich surface chemistry, and excellent mechanical characteristics. However, the strong interlayer van der Waals forces induce significant layer restacking, which restrict complete exposure of MXenes' surface active sites, impeding electron/ion transport and resulting in poor electrochemical performances. Herein, a porous MXene/carbon nanotube (CNT) film was prepared through a simple alkali-induced process. The developed porosity and the introduction of CNTs can effectively suppress the restacking of MXene nanosheets, promoting the effective utilization of the surface active sites of the MXene and facilitating fast ion/electron transportation. Consequently, the porous MXene/CNT film exhibited a high specific capacitance of 401.4 F g(-1) A and a sustained capacitance of 336.2 F g(-1) at an ultrahigh current density of 1000 A g(-1), corresponding to an 83.8% capacitance retention. Furthermore, the film electrode demonstrated outstanding cycling stability, with a capacitance retention of 99.0% after 20,000 cycles at 100 A g(-1), showing its significant potential for supercapacitor applications.