Design and fabrication of high-performance ZnCo₂O₄/ZnWS₄ composite electrode materials for advanced asymmetric supercapacitors

At present, supercapacitors generally have a low energy density, which restricts their wide application. In this study, a series of composite electrode materials based on ZnCo₂O₄ were successfully prepared by the hydrothermal method. The ZnCo₂O₄/ZnWO₄ composite electrode can reach 497.4 C cm⁻² under the test condition of 1 mA cm⁻². The areal specific capacity of the ZnCo₂O₄/ZnWS₄ composite electrode can reach 1286.5 C cm⁻² under the same test condition of 1 mA cm⁻², while the capacitance of ZnCo₂O₄ is only 344.8 C cm⁻² under the same conditions. In addition, an asymmetric supercapacitor was assembled with the ZnCo₂O₄/ZnWS₄ electrode. The test results show that its maximum energy density is 63.2 Wh kg⁻¹, and the corresponding power density is 4066 W kg⁻¹.