A facile method synthesizing marshmallow ZnS grown on Ti3C2 MXene for high-performance asymmetric supercapacitors

Two dimensional (2D) layered material MXene (Ti3C2 ) is an ideal electrode material for supercapacitors because of its unique two-dimensional structure, excellent physical and chemical properties and electrochemical properties. However, the spontaneous collapse of layered structures and the inherent shortcomings of a single material severely limit their application in the field of energy storage. A new strategy was proposed to improve the performance of Ti3C2 -based supercapacitors. Here, Marshmallow ZnS was successfully introduced into the interlayer and surface of MXene by one-step solvothermal method, and a new type of MXene/ZnS composite was constructed. The composite has both the layered morphology of MXene and the marshmallow morphology of ZnS, thus constructing a reasonable spatial network structure. Based on the successful construction of the structure, the collapse defect of the MXene structure is suppressed, providing more surface active sites. At the same time, the addition of high conductivity ZnS can improve the energy storage performance of the composite. Therefore, the new composite delivers excellent supercapacitive properties. Its specific capacity can reach 2347.2 C g(-1) at 1 A g(-1), which is about 9.2 time that of MXene. More importantly, the energy density of a supercapacitor assembled with the composite as a positive electrode can reach 31.8 Wh kg( -1).