MXene-reduced graphene oxide heterostructures as binder-free cathodes for zinc-ion hybrid supercapacitors with superior performance

MXene exhibits significant promise as a cathode material for zinc-ion hybrid supercapacitors (ZHSCs) because of its remarkable physicochemical characteristics. However, the self-stacking and aggregation of two-dimensional MXene nanosheets limits the performance of ZHSCs. In this paper, MXene-reduced graphene oxide (rGO) heterostructures are prepared by a one-step method as binder-free cathode materials for ZHSCs. The integration of rGO nanosheets within MXene layers efficiently mitigates the self-stacking tendency of MXene nanosheets and widens their interlayer spacing, significantly enhancing ionic accessibility and facilitating ion transport within the structure. As a cathode material for ZHSCs, the MXene-rGO heterostructure exhibits remarkable electrochemical performance. The MXene-rGO cathode achieves a specific capacitance of up to 660 F g- 1 at 0.5 A g- 1, and demonstrates an energy density of 86.4 Wh kg- 1 at a power density of 222.3 W kg- 1, surpassing the majority of MXene-based cathodes previously documented for ZHSCs. The cathode also exhibits excellent cyclability with maintaining a capacity retention of 87.7 % after 10,000 cycles. The ease of production and outstanding performance of the MXene-rGO heterostructure suggests its potential as a highly promising cathode material for practical applications in ZHSCs.