This complete investigation presents a combined experimental and computational Approach to emergent high-performance nickel cobalt sulfide (NiCo2S4) nanostructures for Supercapacitor applications. NiCo2S4 samples were synthesised via a two-step solvothermal Method at temperatures of 120–180 °C (designated NCS1-NCS4) and scientifically characterised using XRD, BET, SEM, XPS and FTIR. The optimised NCS4 electrode exhibited a notable specific capacitance of 920.04 Fg− 1 from cyclic voltammetry and 375 Fg− 1 from galvanostatic Charge-discharge measurements. DFT calculations revealed that the (111) surface has the lowest surface energy (0.85 Jm− 2) and the highest electrochemical activity, while nickel vacancies have the lowest formation energy (1.8 eV) under Ni-poor conditions. ML models achieved R2 = 0.97 in predicting capacitance, with synthesis temperature identified as the most critical parameter (importance: 0.28). A Comparative analysis of simulated and experimental results showed excellent agreement (average deviation < 5%). The symmetric supercapacitor device achieved an exceptional specific capacitance of 1234.89 Fg− 1, an energy density of 42.9 Whkg− 1, a power density of 735 Wkg− 1, and 82.82% capacitance retention after 5000 cycles. Pre-fabrication analysis indicated optimal mass loading of 1.5 mg cm− 2 and electrode thickness of 200 nm for device development. This integrated methodology provides a comprehensive framework for the rational design of transition metal sulfide electrodes, with applications in electric automobiles, portable semiconductor technology, renewable energy storage, and industrial power systems.
Pathan et al. (Mon,) studied this question.