Electrochemical performance of Ni-based chalcogenide electrode materials for next-generation energy storage applications

The global energy crisis, driven by excessive dependence on non-renewable fossil fuels, has accelerated the demand for advanced electrochemical energy storage systems with simultaneously high energy and power densities. In this context, supercapattery devices have emerged as a promising alternative by integrating the high energy density of batteries with the rapid charge-discharge capability of supercapacitors. Herein, a facile and cost-effective home-made chemical vapor deposition (CVD) strategy is reported for the fabrication of transition metal (Cd, Ni) chalcogenides (S, Se and Te) heterostructured electrodes for supercapattery applications. A systematic comparison of NiS, S-CdNiS, Se-CdNiS, and Te-CdNiS electrodes establishes a clear electrochemical performance correlation, which has rarely been explored for Cd-incorporated nickel chalcogenide systems. Among them, binder-free S-CdNiS electrode exhibits exceptional electrochemical performance, primarily attributed to its unique cauliflower-like hierarchical nanostructure composed of highly interconnected nanofibers. This architecture generates a mesoporous network with high specific surface area (99.87 m2/g), offering abundant electroactive sites, accelerated ion diffusion pathways, and enhanced charge-transfer kinetics. Electrochemical analysis of the optimized electrode delivers an ultrahigh specific capacitance (2465 F/g at 1 A g−1), along with high energy density (101 Wh/kg) and power density (1896 W/kg). Notably, the electrode demonstrates excellent cycling durability with high coulombic efficiency (95%) and capacity retention (91%), highlighting its structural robustness and reversible redox behavior. Furthermore, a high-performance asymmetric supercapattery device assembled using S-CdNiS as positive electrode and activated carbon as negative electrode (S-CdNiS//AC) exhibits a high specific capacitance (348 F/g), energy density (85 Wh/kg), and power density (7500 W/kg), while maintaining 78% capacity retention and 87% coulombic efficiency even after 10,000 charge-discharge cycles. This work uniquely demonstrates that synergistic Cd incorporation and anion engineering via a scalable CVD strategy can simultaneously optimize morphology, surface chemistry, and electrochemical kinetics, offering a new design paradigm for next-generation supercapattery electrodes.