Speaker
Description
Combining high energy and power density makes supercapacitors promising candidates for high‑power applications, though their energy density remains lower than that of traditional batteries, largely due to limitations in electrode quantum capacitance. Double transition metal (DTM) MXenes, with their distinctive electronic properties, offer strong potential as electrode materials. In this study, density functional theory (DFT) was applied to evaluate TiₐVᵦC₍ₐ₊ᵦ₋₁₎ MXenes—comprising two to four transition metal layers—for use in electrochemical double‑layer capacitors (EDLCs). Phonon dispersion and ab initio molecular dynamics confirmed their dynamic and thermal stability, while elastic constant and Young’s modulus analyses demonstrated mechanical robustness superior to mono‑transition‑metal MXenes. Electronic structure evaluations revealed good conductivity in all but semi‑metallic TiVC. Quantum capacitance calculations identified Ti₂V₂C₃ as exhibiting the highest integrated quantum capacitance values above 1300 μF/cm² in both ionic/organic and aqueous electrolytes. Comparison with mono‑transition‑metal MXenes and other known materials underscores the strong promise of these DTM MXenes as next‑generation supercapacitor electrode materials.