CoSe nanoparticles supported NiSe2 nanoflowers cathode with improved energy storage performance for advanced hybrid supercapacitors

This work proposed a facile synthesis of NiSe2-CoSe nanocomposite via an economical wet-chemical assisted method for the electrochemical energy storage domain, specifically for supercapacitor applications. The morphological, structural, and surface chemistry characterization guarantee the appropriate formation of the micro flower and nanoparticles-like morphology with high purity, crystallinity, and the existence of Ni, Co, and Se elements on the surface of the samples was verified by EDX examination. The comparative electrochemical properties reveal that the NiSe2-CoSe nanocomposite electrode yields an optimized performance than NiSe2 and CoSe electrodes in an aqueous solution with improved capacitance and charge transport kinetics. The synergistic effect between metal selenide nanomaterials could effectively realize the excellent charge storage properties of the NiSe2-CoSe nanocomposite. Strikingly, a voltage runs to 1.7 V by assembling a hybrid supercapacitor of NiSe2-CoSe||AC||KOH in the two-electrode mode for utilization towards the practical aspect. More specifically, high stability of 89.6 % was sustained at 20 A/g for 20,000 cyclings with durable performance. Additionally, a high power of 8460 W/kg was achieved when the energy density progressively reached 54.9 Wh/kg. The use of chalcogenide is now the top priority for electrochemical energy conversion and storage, thanks to these encouraging results.