High-performance solid-state asymmetric supercapacitor based on Ti3C2Tx MXene/VS2 cathode and Fe3O4@rGO hydrogel anode

Herein, we report the synthesis of MXene/VS2 composites for asymmetric supercapacitors using a hydrothermal method. Impressively, the resulting MXene/VS2 electrode shows an outstanding specific capacity of 895.7 C g−1 (1791.4 F g−1) at 1 A g−1, rate capability (587.5 C g−1 (1175.0 F g−1) at 20 A g−1), and cycle performance (90.6% capacity retention after 10,000 cycles), owing to its specific microstructures with connected nanosheets and enhanced electrochemical conductivity arising from the synergistic effect of VS2 and conductive MXene. To achieve higher energy density in the solid-state asymmetric supercapacitor (ASC) device, Fe3O4 nanoparticles uniformly dispersed and encapsulated into the rGO sheets (Fe3O4@rGO) as a negative electrode is also designed. The obtained MXene/VS2 was used as a cathode and Fe3O4@rGO acted as a anode. Further, an assembled MXene/VS2//Fe3O4@rGO ASC device delivered an impressive specific capacitance of 365.4 C g−1 (228.4 F g−1) at 1 A g−1, in addition, the device yielded the specific energy of up to 73.9 Wh kg−1 at the corresponding specific power of 728.2 W kg−1 with superior cycling performance (90.7% capacity retention after 10,000 cycles at 8 A g−1), demonstrating its high potential for applications in high-porformance energy storage devices.