Aestivum-inspired photothermal 3D-MXene-unity membrane-aerogel for flexible supercapacitor with solar enhanced performance

Designing high gravimetric capacitance, flexible, and functional structural electrodes based on 2D nanomaterials is crucial for wearable electronics, however, it is still limited by serious restacking problems and uncontrollable assembly processes. Herein, inspired by a specialized network of rigidity-flexible integration in aestivum, an effective half-dry 2D-1D-2D pre-assembly combined with an “ice templating” strategy was proposed to construct a novel 3D-MXene-unity membrane-aerogel for the desirable supercapacitor substrate with energy harvesting capacity, addressing the incompatible contradiction between electrochemical properties and desirable mechanical strength. With cellulose nanofiber serving as a 1D structural modifier as well as black-phosphorus nanosheets applied as a 2D restacking reliever and electron-conductive network jointer, the multi-leveled mimicked topology facilitated the configured complexity of the membrane-aerogel can be achieved to be utilized in multifunctional composite electrodes. The resulting super-flexible and net-shaped 3D-MXene-unity membrane-aerogel showed low-tortuosity topology, superior electron-conductive network (870 S/cm), outstanding mechanical strength (53.2 MPa), and favorable electrochemical property (215 F/g), hardly achieved in a single system. Because of the synergistic photo-thermal capability from MXene and BP, assembled supercapacitors can harvest energy from sunlight and result in a 196% enhancement in capacitance. This work would lay a significant foundation for the construction of high-performance flexible energy storage devices.