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

In this study, the synthesis of a MXene (Ti₃C₂T_x)-derived TiO₂/starbon (M-TiO₂/Starbon-800 °C) nanocomposite using a facile calcination method is explored. High-temperature exposure transforms layered Ti₃C₂T_x 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 (C_sp) of 1352 Fg⁻¹ at 1 Ag⁻¹, while retaining more than 99% of its C_sp after 50 000 charge/discharge cycles. Furthermore, when incorporated into a two-electrode symmetric coin cell, it demonstrates a C_sp 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.