Highly efficient alkaline aqueous MXene-based asymmetric supercapacitors developed by corrugation-like MoS2 and WS2 modified CMX electrodes

Abstract

The preparation of superior performance supercapacitors to achieve high energy density, fast charge-discharge speed and long cycle stability characteristics has become the focus of attention to realize their potential as practical energy storage devices. In this paper, a cross-linking CNTs@MXene (CMX) architecture is selected as the negative electrode to increase the contact area with electrolyte, and corrugation-like morphologies MoS2 and WS2 nanoparticles modified CMX (Mo/W-CMX) two-dimensional nanostructure as the positive electrode to provide multiple ion diffusion through its channels structure, which presents good electrochemical performance with high specific capacitance and high energy density in 1 M KOH alkaline electrolyte. CNTs introduced into MXene interface by bridges can effectively impede the re-stacking of MXene, meanwhile, CMX as a matrix can also alleviate the properties degradation caused by the agglomeration and volume strain for sulfides. Benefiting from the facilitate accessibility of ions and high ability of electron transfer, the prepared Mo/W-CMX electrode exhibits a dramatic specific capacitance of 1160 F g−1 at 1 A g−1 and excellent capacitance retention of 88.67% at 25 A g−1 after 10,000 cycles. Meanwhile, the assembled asymmetric supercapacitor (Mo/W-CMX // CMX) presents an ultrahigh energy density of 28.1 Wh kg−1 at the power density of 697.3 W kg−1 and maintains 81.25% cycle stability at 15 A g−1 for 10,000 charge-discharge cycles. It is essential to highlight that the superior performance fabricated asymmetric supercapacitor holds a wide application prospect and very competitive energy-storage values in the upgrading of new high-performance devices.