Synergetic Effectof <i>In Situ</i> FormedTiO₂ in MXene for Enhanced Energy Storage in High-PerformanceSupercapacitors

This study explores and presents a comprehensive understanding of the synergistic effect of in situ formed TiO₂ in Ti₂C MXene (TTMXene) nanomaterials to derive enhanced energy characteristics in high-performance flexible symmetric supercapacitors. The TTMXene two-dimensional (2D) (nanocomposite) materials were synthesized by a simple single-step chemical etching method. The TTMXene thus formed exhibits a layered structure with an average particle size in the range of 10–50 nm. The electrochemical studies demonstrate that the TTMXene nanocomposite exhibits a specific capacitance of 729 F g^–1 at a current density of 0.5 A g^–1. This enhanced performance is due to utilization of a high active surface area and excellent electronic conductivity of the <i>in-situ</i> formed TiO₂ in Ti₂C MXene. The prototype of a flexible symmetric TTMXene supercapacitor was fabricated and characterized. The TTMXene//TTMXene demonstrated an excellent energy density of 152.3 Wh kg^–1 at a power density of 0.215 kW kg^–1 and retained 88% specific capacitance after 10,000 cycles. These findings highlight that the TTMXene nanocomposites are exceptional candidates for future flexible supercapacitor devices with long-term and superior performance.