High‐Performance Flexible and Symmetric Supercapacitors Based on Micro‐Flower‐Like MnSe@Ti <sub>3</sub> C <sub>2</sub> T <sub>x</sub> Heterostructure
Siyan Li, Qian Song, Chunlei Fang, Yong Lu, Xiaokang Ding, Ting Liu, Jicai Zhang, Fu‐Jian Xu
Abstract
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.