TiO ₂ –MnO ₂ Nanocomposites for High‐Performance Supercapacitors in Imidazolium‐Based Ionic Liquids

Supercapacitors are emerging as efficient energy storage devices due to their high power density and rapid charge–discharge capabilities. Their performance, however, is often restricted by electrode materials with low capacitance and limited cycling stability. To address this challenge, we synthesized and optimized TiO ₂ –MnO ₂ nanocomposites with improved colloidal stability and reduced particle size for enhanced electrochemical behavior. The synergistic interaction between TiO ₂ and MnO ₂ at a 25:75 ratio significantly improves ion diffusion, redox activity, and electrical conductivity, resulting in efficient charge storage. Structural characterization confirms the formation of a well‐optimized nanostructure that supports fast electron transport and stable electrochemical response. Electrochemical tests reveal a high specific capacitance of 1749 F/g at 3.3 A/g, strong rate capability, and minimal capacitance degradation during long‐term cycling. The optimized nanocomposite outperforms the unoptimized material and previously reported systems in both energy and power density. Long‐cycle testing further demonstrates excellent stability with significant capacitance retention. Additionally, density functional theory (DFT) confirms the strong interaction of TiO ₂ –MnO ₂ with imidazolium‐based electrolytes, indicated by a negative Gibbs free energy (−128.67 kcal/mol) and reduced bandgap (0.484 eV). Overall, the optimized TiO ₂ –MnO ₂ composite is a promising electrode material for next‐generation high‐performance supercapacitors.