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

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 Ti3C2Tx electrode for high-performance supercapacitors. The electrode prepared from the K+ assisted self-assembly of Ti3C2Tx nanosheets (named as Ti3C2Tx-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 Ti3C2Tx, 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.