Nanoarchitectonics of MXene Derived TiO 2 /Graphene with Vertical Alignment for Achieving the Enhanced Supercapacitor Performance.

Structural engineering and hybridization of heterogeneous 2D materials can be effective for advanced supercapacitor. Furthermore, architectural design of electrodes particularly with vertical construction of structurally anisotropic graphene nanosheets, can significantly enhance the electrochemical performance. Herein, MXene-derived TiO ₂ nanocomposites hybridized with vertical graphene is synthesized via CO ₂ laser irradiation on MXene/graphene oxide nanocomposite film. Instantaneous photon energy by laser irradiation enables the formation of vertical graphene structures on nanocomposite films, presenting the controlled anisotropy in free-standing film. This vertical structure enables improved supercapacitor performance by forming an open structure, increasing the electrolyte-electrode interface, and creating efficient electron transport path. In addition, the effective oxidation of MXene nanosheets by instantaneous photon energy leads to the formation of rutile TiO ₂ . TiO ₂ nanoparticles directly generated on graphene enables the effective current path, which compensates for the low conductivity of TiO ₂ and enables the functioning of an effective supercapacitor by utilizing its pseudocapacitive properties. The resulting film exhibits excellent specific areal capacitance of 662.9 mF cm ^-2 at a current density of 5 mA cm ^-2 . The film also shows superb cyclic stability during 40 000 repeating cycles, maintaining high capacitance. Also, the pseudocapacitive redox reaction kinetics is evaluated, showing fast redox kinetics with potential for high-performance supercapacitor applications.
(© 2023 The Authors. Small published by Wiley-VCH GmbH.)