Flexible, self-supporting Ti3C2Tx thin film electrodes prepared through vacuum filtration and applied for supercapacitors

The remarkable characteristics of 2D MXene enable its use in energy storage. However, challenges associated with their oxidation and aggregation can limit their performance in energy storage devices. This study systematically explores the unique low-layer Ti3C2Tx nanosheet microstructure with various thicknesses to analyze their potential as electrode materials in supercapacitors. The morphology analysis revealed the excellent lamellar structure and flexibility of prepared MXene thin film electrodes. The cross-section SEM shows the thin film's orderly, parallel, and compact stacked nanosheets, leading to the excellent flexibility of thin films. The thin film electrode with 17.3 μm thickness exhibited the best electrochemical performance among other samples to achieve a specific capacitance of 293.3 F g-1 at the current density of 1 A g-1. After 8000 cycles, the capacity retention rate is as high as 91%, indicating the high stability of the layered structure of the MXene film. The energy density of the device assembled with MXene thin film electrode can still reach 5.8 Wh kg-1 at 1000 W kg-1 power density. The diffusion control process dominates the electrochemical energy storage behaviour. The assembled symmetric supercapacitor presents a specific capacitance of 54.3 F g-1 at a current density of 1 A g-1.