Template-free synthesized 3D macroporous MXene with superior performance for supercapacitors

Abstract MXene is a promising material for supercapacitor due to its unique physical and chemical properties. However, traditional fabrication methods of electrode often result in restacking of MXenes nanosheets, leading to the insufficient utilization of electrochemical performance. Therefore, it is a great challenge in actual applications for us to improving the restacking of electrode materials by designing optimum electrode structures. Herein, we reported a fabrication of 3D macroporous MXenes film (3d-Ti3C2Tx-film) and aerogel by liquid nitrogen rapid freezing. The specific area increased by 5 and 22 times compared with the Ti3C2Tx-film (prepared by vacuum filtered and dried in air). The huge specific surface area enhances double-layer capacitance and provides more surface active sites. The specific capacitance of 3d-Ti3C2Tx-film and aerogel is 372 F g−1 (1355 F cm−3) and 404 F g−1 (1293 F cm−3) at a current density of 1 A g−1 in a 3 M H2SO4 electrolyte, respectively. Moreover, the supercapacitor fabricated with 3d-Ti3C2Tx-film displays an outstanding volumetric energy density of 32.2 Wh L−1 at the power density of 946 W L−1. The fabrication method by liquid nitrogen rapid freezing is more environmental friendly, simpler and lower cost compared to the template method. Furthermore, the 3D macroporous MXene is expected to be applied in the fields of ion battery, seawater purification and photocatalysis.