Assembling MnCo2O4 nanoparticles embedded into MXene with effectively improved electrochemical performance

Abstract

MXene is an ideal candidate material for supercapacitor electrode due to their unique accordion-like structure, large specific surface area, remarkable conductivity and excellent chemical stability. Due to the large surface energy between layers, it is easy to stack between layers of MXene, and the energy storage field between the layers cannot be fully utilized. Therefore, increasing the interlayer spacing of MXene is a research focus to enhance electrochemical performance. The spinel ternary metal oxide MnCo2O4 have been extensively investigated as electrode materials due to low-cost and highly theoretical capacitances. Moreover, manganese ions can improve the rate performance of the material, and cobalt ions have a higher oxidation potential. Herein, the interlayer spacing of MXene is increased by introducing nano-scale MnCo2O4 particles. The as-prepared optimal electrode material exhibits a specific capacity of 806.7 F g−1 at a current density of 1 A g−1, and excellent cycle stability. The asymmetric supercapacitor device is assembled by the obtained electrode as the positive electrode and activated carbon as the negative electrode, which the device can provide energy density of 26.8 Wh kg−1 at power density of 2.88 kW kg−1 with excellent cycle stability (93.8% capacity retention after 5000 cycles at a current density of 5 A g−1). The research proposes a simple hydrothermal method was used to prepare a high-performance MXene-based supercapacitor.