High‐Performance Flexible and Symmetric Supercapacitors Based on Micro‐Flower‐Like MnSe@Ti3C2Tx Heterostructure

Abstract Flexible supercapacitors, renowned for their exceptional power density and cycling stability, are a focus in the field of energy storage. Ti 3 C 2 T x MXene is a promising electrode material for supercapacitors owing to its excellent metallic conductivity. However, its stacking layered structure limits device performance on specific capacitance, operating voltage, and energy density. Herein, a MnSe@Ti 3 C 2 T x heterostructure is developed to enhance the electrochemical performance of Ti 3 C 2 T x ‐based electrode materials. With the solvothermal synthesis method, MnSe nanosheets are in situ grown on Ti 3 C 2 T x surface to form micro‐flower‐like MnSe@Ti 3 C 2 T x heterostructures by adjusting the ratio of ethanolamine solvent and the amount of Ti 3 C 2 T x . The specific capacitance of the optimized heterostructure (E 3 /MnSe@Ti 3 C 2 T x ‐45) is as high as 721.4 F g −1 at 1 A g −1 , approximately ten times higher than that of pure Ti 3 C 2 T x . The MnSe@Ti 3 C 2 T x flexible symmetric supercapacitor (MT‐FSC) based on E 3 /MnSe@Ti 3 C 2 T x ‐45 exhibits a wide working voltage window of 1.2 V and a large energy density of 28.68 Wh kg −1 at 308.23 W kg −1 . The capacitance retention rate keeps 90.77% after 4000 charge–discharge cycles. Furthermore, MT‐FSC can power LEDs even under large‐angle (90°) bending. This heterostructure electrode material not only improves the electrochemical performance of Ti 3 C 2 T x ‐based flexible supercapacitors but also offers a robust energy supply for flexible wearable electronic devices.