An emerging supercapattery device with Cu0.2Ni0.8Co2S4 cathode for pertinent electrochemical energy storage

This study explores the application of CuCo 2 S 4 and its Ni-substituted forms (Cu x Ni 1-x Co 2 S 4 ) as active materials for electrochemical energy storage (EES). Incorporating Ni into the CuCo 2 S 4 matrix significantly improved its EES performance. Cu 0.2 Ni 0.8 Co 2 S 4 delivered high specific capacitance (C sp ) and energy density (E d ) of 1545.87 F g −1 and 46.08 W h kg −1 , respectively, at 2 A g −1 . It also delivered a power density (P d ) of 1947.89 W kg −1 at 10 A g −1 . The supercapattery device, AC//Cu 0.2 Ni 0.8 Co 2 S 4 , demonstrated high performance metrics with a high P d of 8000.51 W kg −1 at an E d of 34.78 W h kg −1 , at 10 A g −1 . This work contributes to the growing body of knowledge on sustainable energy solutions and facilitates the practical implementation of thiospinels in next-generation electrochemical devices.