Self‐Healing Microsupercapacitors with Size‐Dependent 2D MXene

Abstract 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.