High-performance MXene/aramid nanofibers/graphene film electrodes with superior integration of mechanical and capacitive properties

Film electrodes assembled with MXene have attracted excellent attention for applications in flexible energy storage systems. However, the poor mechanical performance and restricted capacitive surface are limiting factors for the development of high-performance MXene-based supercapacitor. Herein, a MXene-based film electrode with the remarkable integration of mechanical and capacitive properties was provided by using aramid nanofibers/reduced graphene oxide (ANFs/rGO) as reinforcing filler, which achieved 7- and 17-times improvements in tensile strength and toughness, respectively, compared with pure MXene film. Due to the careful regulation of the lamellar structure by introducing ANFs/rGO, the composite film electrode showed a superb volumetric capacitance of 349.2 F cm−3 at a current density of 1 A cm−3. Moreover, a solid-state supercapacitor based on the composite film delivered a maximum energy density of 15.5 mWh cm−3 at a power density of 0.47 W cm−3. The optimal structure-function relationship realized in this work validates the feasibility of optimizing MXene film electrode by ANFs/rGO.