CNT-network-engineered V2Se9/CoSe2 heterostructures for thermally robust high-performance supercapacitors with machine-learning-assisted performance prediction

Engineering conductive heterointerfaces in transition-metal selenides is an effective strategy for improving charge-transfer kinetics, redox-site accessibility, and cycling durability in supercapacitor electrodes. Herein, selenium-rich V 2 Se 9 , V 2 Se 9 /CoSe 2 heterostructures, and CNT-integrated V 2 Se 9 /CoSe 2 composites were prepared through a rapid microwave-assisted strategy. Cobalt incorporation was used to create redox-active heterointerfaces, while CNT loading was varied to examine its influence on conductive-network formation and electrochemical performance. Structural, microscopic, and surface analyses confirmed the coexistence of V 2 Se 9 and CoSe 2 domains and supported CNT-assisted interfacial contact. The optimized CNT 3 -CoVSe electrode delivered a high specific capacitance of 877.59 F/g at 1 A/g and retained 267.14 F/g at 10 A/g. Electrochemical impedance spectroscopy showed accelerated charge-transfer kinetics, with the charge-transfer resistance reduced to 6.241 Ω. Temperature-dependent testing demonstrated thermally adaptive behavior, with capacitance increasing from 825.90 F/g at 0 °C to 968.10 F/g at 50 °C before declining slightly at higher temperature. Machine-learning-assisted response-surface analysis mapped the coupled effects of temperature and current density, with the ANN model providing the most reliable prediction. The symmetric device delivered 63.44 Wh/kg at 953.99 W/kg and retained 80% capacitance after 13,000 cycles, confirming the potential of CNT-network-engineered V 2 Se 9 /CoSe 2 electrodes for thermally robust high-performance supercapacitor applications.