Exploration of high performance and highly flexible supercapacitor configuration with MXene/1T-MoS2 composite paper electrode

In the case of increasing shortage of non-renewable resources, developing high-efficiency and high-capacity energy storage devices is critical. Supercapacitors have the potential of high-efficiency and high-capacity. MXene and 1T-MoS2 are two kinds of high performance pseudocapacitive materials. However, the stacking and aggregation of MXene nanosheets greatly reduce its capacity. The poor conductivity of 1T-MoS2 also limits the full expression of its excellent pseudocapacitive performance. A flexible MXene/1T-MoS2 composite paper electrode is designed and prepared in this work where the restacking of MXene can be relieved and the whole electrode maintains the conductivity. The interior stacking structure of MXene and 1T-MoS2 in the composite paper, as well as the gel electrolyte type are explored. The device constructed with the electrode composed of randomly stacked MXene and 1T-MoS2 (mass ratio 6:1) and acidic electrolyte (PVA/H2SO4 gel electrolyte) demonstrates the optimal performance. The specific areal and volumetric capacitances reach 561.2 mF cm-2 and 1268.17 F cm-3 at the current density of 0.8 mA cm-2 respectively, outperforming most of the previously reported values for MXene based supercapacitors tested in gel electrolyte. The supercapacitor has excellent deformation durability and long cycle stability, demonstrating promising prospect in future flexible electronics.