Investigating the electronic properties and quantum capacitance of transition metal sulfides MS2 (M = Ti, Mo, W, V, Nb, Ta, Fe, Cu, Co): A DFT study for high-performance supercapacitors

Developing high-performance supercapacitors necessitates exploring advanced electrode materials with rapid charge-discharge kinetics, high power density, and long-term electrochemical stability. This study employs DFT to unravel the electronic properties, quantum capacitance (C Q ), surface charge density(σ), and thermodynamical stability of nine transition metal disulfides (MS 2 : M = Ti, Mo, W, V, Nb, Ta, Fe, Cu, and Co), highlighting their potential as advanced supercapacitor electrodes. Computational analyses reveal significant contrasts in performance, with layered TiS 2 , TaS 2 , and MoS 2 exhibiting high C Q values of 1313.41 μF cm −2 , 1111.29 μF cm −2 , and 943.75 μF cm −2 , respectively. Remarkably, non-layered FeS 2 exhibits a competitive C Q value of 923.73 μF cm −2 while ranking as the thermodynamically most stable compound. σ analysis further revealed TiS 2 (710.84 μC cm −2 ) and FeS 2 (653.14 μC cm −2 ) as top performers, confirming their suitability as anode materials . In contrast, CuS 2 and CoS 2 have low C Q , underscoring their limited utility. The findings guide electrode material selection and encourage experimental and engineering strategies, such as heterostructure and defect modulation, to fully unlock these systems' potential. A strong correlation between DFT-predicted and experimental capacitance values validates the computational framework, confirming its reliability for guiding future electrode material design.