High-performance asymmetric supercapacitor applications enabled by nickel foam-supported CoTe/NiCo2S4 core-shell nanorods

The quest to achieve high energy density and superior stability in supercapacitors is both attractive and challenging. This work reports a simple method to grow CoTe/NiCo 2 S 4 composite electrode materials with core-shell structure. When used as a cathode material, the unique core-shell structure exhibits outstanding electrochemical characteristics, including a superior specific capacitance (1470.45 F g −1 at 1 A g −1 ), outstanding cycling stability (86.69 % after 5000 cycles), and impressive rate performance (77.17 % at 10 A g −1 ). Notably, the asymmetric hybrid supercapacitor constructed using CoTe/NiCo 2 S 4 as the cathode and AC/NF as the anode can provide an operating voltage of 1.8 V, achieving a peak energy density of 39.8 Wh kg −1 and a highest power density of 832 W kg −1 . Moreover, the supercapacitor demonstrates satisfactory rate performance (81.25 % at 10 A g −1 ) and excellent cycling stability (86.61 % after 8000 cycles). Furthermore, when assembled into a quasi-solid-state flexible supercapacitor, the device can support a small toy fan to run for 66 seconds, thereby highlighting its viability for practical energy storage applications.