Facile fabrication of flexible rGO/MXene hybrid fiber-like electrode with high volumetric capacitance

Graphene fibers or fiber-like graphene materials have been successfully adopted as electrodes for flexible and wearable supercapacitors. However, they normally exhibit relatively low volumetric capacitance, which will seriously hinder their wide applications in smart textile as power supply. Here, a facile confined hydrothermal strategy to fabricate fiber-like reduced graphene oxide (rGO)/MXene hybrids is designed through ingenious assemble of two functional two dimensional materials of graphene and MXene nanosheets. Owing to the synergistic interactions between two layers, the hybrid rGO/M − 5 exhibits a large volumetric capacitance of 345 F cm−3 with the gravimetric capacitance of 195 F g−1 at 0.1 A g−1 with only 5 wt% MXene layers. A volumetric energy density of 30.7 mWh cm−3 with power density of 70.7 mW cm−3 could be delivered. After 7500 cycles at a current density of 0.5 A g−1, about 125% of its initial capacitance value is retained, demonstrating excellent electrochemical stability. More importantly, due to the suppressed oxidation process of MXene sheets in the hybrid, rGO/MXene could retain 95% of its original capacitance after one month.