High-Performance Flexible and Symmetric Supercapacitors Based on Micro-Flower-Like MnSe@TiCT Heterostructure.

Flexible supercapacitors, renowned for their exceptional power density and cycling stability, are a focus in the field of energy storage. TiCT 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@TiCT heterostructure is developed to enhance the electrochemical performance of TiCT-based electrode materials. With the solvothermal synthesis method, MnSe nanosheets are in situ grown on TiCT surface to form micro-flower-like MnSe@TiCT heterostructures by adjusting the ratio of ethanolamine solvent and the amount of TiCT. The specific capacitance of the optimized heterostructure (E/MnSe@TiCT-45) is as high as 721.4 F g at 1 A g, approximately ten times higher than that of pure TiCT. The MnSe@TiCT flexible symmetric supercapacitor (MT-FSC) based on E/MnSe@TiCT-45 exhibits a wide working voltage window of 1.2 V and a large energy density of 28.68 Wh kg at 308.23 W kg. 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 TiCT-based flexible supercapacitors but also offers a robust energy supply for flexible wearable electronic devices.