Self-propagating fabrication of 3D porous MXene-rGO film electrode for high-performance supercapacitors

2D MXene nanosheets with metallic conductivity and high pseudo-capacitance are promising electrode materials for supercapacitors. Especially, MXene films can be directly used as electrodes for flexible super capacitors. However, they suffer from sluggish ion transport due to self-restacking, causing limited electrochemical performance. Herein, a flexible 3D porous MXene film is fabricated by incorporating graphene oxide (GO) into MXene film followed by self-propagating reduction. The self-propagating process is facile and effective, which can be accomplished in 1.25 s and result in 3D porous framework by releasing substantial gas instantaneously. As the 3D porous structure provides massive ion-accessible active sites and promotes fast ion transport, the MXene-rGO films exhibit superior capacitance and rate performance. With the rGO content of 20%, the MXene-rGO-20 film delivers a high capacitance of 329.9 F g(-1) at 5 mV s(-1) in 3 M H2SO4 electrolyte and remains 260.1 F g(-1) at 1,0 0 0 mV s(-1) as well as good flexibility. Furthermore, the initial capacitance is retained above 90% after 40,000 cycles at 100 A g(-1), revealing good cycle stability. This work not only provides a high-performance flexible electrode for supercapacitors, but also proposes an efficient and time-saving strategy for constructing 3D structure from 2D materials. (c) 2020 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.

Automated summary

In this study, a flexible 3D porous MXene film was prepared by incorporating graphene oxide (GO) into the MXene film and then undergoing self-propagating reduction. The 3D porous structure improved ion transport efficiency, resulting in superior capacitance and cycle stability of the MXene-rGO films.