Plasma-driven interlayer engineering of MXenes for high-performing supercapacitor electrodes

2D MXenes hold great potential for energy storage, particularly in supercapacitors, due to their remarkable electrical conductivity and electrochemical activity. However, restacking and limited active sites as stand-alone materials restrict their performance by minimizing ionic transport. This study demonstrates a rapid, scalable, and solvent-free plasma-assisted surface and interlayer engineering approach to enhance the electrochemical activity of Ti 2 C MXene. Conventional wet chemistry etching was used for synthesizing Ti 2 C, and sulfur (S) and oxygen (O 2 )-containing plasma were employed to partially replace the surface fluorine ( F) terminations and intercalate heteroatoms in the interlayers. The S-plasma-engineered MXenes were used as an electrode for supercapacitors, achieving specific capacitances of 733 F g −1 (330C g −1 ) at 1 A g −1 , compared to 62 F g −1 (28C g −1 ) for the untreated Ti 2 C with good cycling stability, rate capability, and structural integrity. Furthermore, an asymmetric device assembled with S-Ti 2 C//AC delivered a capacitance of 19 F g −1 and a high-power density of 1494 W kg −1 . These results demonstrate that the plasma-assisted strategy is a highly efficient and sustainable approach for surface and interlayer engineering of MXene, resulting in significant improvements in energy storage performance and making them promising candidates for next-generation supercapacitors.