Nanoarchitectonics of MXene Derived TiO2 /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 TiO2 nanocomposites hybridized with vertical graphene is synthesized via CO2 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 TiO2 . TiO2 nanoparticles directly generated on graphene enables the effective current path, which compensates for the low conductivity of TiO2 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.

MXene-Derived TiO2/Starbon Nanocomposite as a Remarkable Electrode Material for Coin-Cell Symmetric Supercapacitor.

In this study, the synthesis of a MXene (Ti3C2Tx)-derived TiO2/starbon (M-TiO2/Starbon-800 °C) nanocomposite using a facile calcination method is explored. High-temperature exposure transforms layered Ti3C2Tx into rod-like TiO2 and starbon into amorphous carbon. The resulting M-TiO2/Starbon-800 °C nanocomposite exhibits a significantly larger surface area and pore volume compared to its individual components, leading to superior electrochemical performance. In a three-electrode configuration, the nanocomposite achieved a specific capacitance (Csp) of 1352 Fg⁻¹ at 1 Ag⁻¹, while retaining more than 99% of its Csp after 50 000 charge/discharge cycles. Furthermore, when incorporated into a two-electrode symmetric coin cell, it demonstrates a Csp of 115 Fg⁻¹ along with exceptional long cycle life. Moreover, the device shows an energy density (ED) of 51 Whkg-1 and a power density (PD) of 7912 Wkg-1 at 5 Ag-1. The enhanced charge storage is attributed to the formation of a porous structure with a high specific surface area resulting from the interaction between M-TiO2 nanorods and starbon, which facilitates efficient ion penetration.