Carbon nanotubes enhance flexible MXene films for high-rate supercapacitors

MXenes are 2D transition metal carbides or nitrides with high electrical conductivity that have attracted great attention as promising electrode materials that supersede carbon-based material designed for supercapacitors. However, the aggregation and self-restacking of MXene 2D nanosheets limit their high-rate performance. In this work, flexible and conductive Ti₃C₂T_x MXene/carbon nanotubes (CNTs) composite film was prepared through a simple vacuum filtration of the Ti₃C₂T_x MXene and CNTs suspension mixture. The CNTs integrated MXene nanosheets can effectively prevent the restacking while creating fast ion transport channels for enhanced capacitance. The designed films exhibit excellent performance as supercapacitor electrodes with high capacitance of 300 F g⁻¹ at 1 A g⁻¹ with superior rate performance of 199 F g⁻¹ even at 500 A g⁻¹, together with excellent cyclic stability of 92% capacitance retention after 10000 cycles at 20 A g⁻¹. The excellent workability demonstrates potential application of the system for flexible, portable and highly integrated supercapacitors.