Self-Healing Microsupercapacitors with Size-Dependent 2D MXene

Graphical A self-healing microsupercapacitor (MSC) based on size-dependent 2D MXene is reported by spray-coating and laser-engraving methods, which is simple, low-cost and large-scalable. Compared with the larger-MXene and mix-MXene (smaller and larger nanosheets 1 : 1 mass ratio), the smaller-MXene-based MSCs exhibit the highest capacitance of 73.6 mF/cm 2 . The MXene-based-MSCs present an excellent self-healing ability with capacitance retention of 90 % over 2000 charge/discharge cycles after 5 th cutting/healing. Very recently, 2D MXene has attracted a lot of attention in energy storage, due to its large specific surface area, good hydrophilicity, good conductivity and adjustable composition. Herein, we reported a kind of self-healing microsupercapacitors (MSCs) based on size-dependent Ti 3 C 2 T x MXene. Due to the rich physicochemical properties of Ti 3 C 2 T x , the MSCs were fabricated by firstly spraying different lateral size MXene nanosheets onto the cellulose paper, and then selectively engraving interdigital electrodes by laser engraving machine. The flexible MXene-based MSCs were assembled by sulfuric acid-polyvinyl alcohol electrolyte. It is observed the electrochemical performance of MXene-based MSCs is significantly affected by the nanosheet size. And the capacitance of MSCs fabricated by smaller lateral nanosheet reached up to 73.6 mF/cm 2 , which is higher than that of the larger lateral nanosheet and mixture one that contains smaller and larger nanosheets (1 : 1 mass ratio). Moreover, the self-healing MXene-based MSCs fabricated with polyurethane containing large number of hydrogen bonds as the wrapped material, present an excellent self-healing ability with capacitance retention of 90 % over 2000 charge/discharge cycles after 5 th cutting/healing. And MXene-based MSCs display great potential in the field of energy storage, which not only turn on the LED light but also drive the electronic clock.