Three-dimensional network structured MnCo2S4/NiCo2S4 electrode materials assembled with two-dimensional nanosheets as basic building units for asymmetric supercapacitor applications

Recently, the construction of morphology and structure is considered to be one of the key factors to improve the cycle stability and rate performance of nanomaterials. Herein, MnCo2S4/NiCo2S4 (MCS/NCS) composites with three-dimensional network structures were fabricated by simple electrodeposition of NiCo2S4 nanosheets on the MnCo2S4 nanosheets framework. Compared with the two-dimensional nanosheet structure, the three-dimensional network structure of MCS/NCS has good capacitive and conductive properties. Also, the effects of electrodeposition time on the morphology and electrochemical properties of the composites were studied. Among them, MCS/NCS-6 stands out for its unique structure and excellent electrochemical properties, exhibiting excellent specific capacity (920 C g−1 at a current density of 1 A g−1) and good cycling stability. More importantly, the fabricated asymmetric supercapacitor MCS/NCS//AC assembly has a high energy density of 45.6 Wh kg−1 (800 W kg−1 power density) and good cycle life (75.6%, 10,000 cycles), demonstrating the potential application of this uniquely structured electrode material in alkaline aqueous energy storage devices such as asymmetric supercapacitors (ASC).