Ion-assisted self-assembly of macroporous MXene films as supercapacitor electrodes

Abstract

MXenes are promising electrode materials for supercapacitors, and hence there is a great demand for a simple, low-cost, and eco-friendly synthesis technique for obtaining MXenes to fully utilize their unique electrochemical performance. In this paper, a facile method using the ion-assisted self-assembly process has been developed to prepare a freestanding macroporous Ti₃C₂T_x electrode for high-performance supercapacitors. The electrode prepared from the K⁺ assisted self-assembly of Ti₃C₂T_x nanosheets (named as Ti₃C₂T_x-K) exhibits an excellent capacitance up to 1025 mF cm⁻² (427 F g⁻¹) at a scan rate of 2 mV s⁻¹ and impressive rate capability and cycle stability. The enhancement of electrochemical performance is attributed to the macroporous structure which effectively avoids restacking of Ti₃C₂T_x, increases the specific surface area, and greatly shortens the diffusion distance of electrolyte ions. The present investigation provides a new approach to synthesize macroporous MXenes for practical application in supercapacitors.