Nanowire-core/double-shell of NiMoO4@C@Ni3S2 arrays on Ni foam: insights into supercapacitive performance and capacitance degradation

Abstract

The one-dimensional-core/double-shell arrays on Ni foam were prepared by the hydrothermal, carbonized and electrodeposition processes, consisting of NiMoO4 nanowire as a core, an ultrathin carbon layer as an internal shell and Ni3S2 nanosheets an external shell (abbr. NiMoO4@C@Ni3S2), respectively. The ternary heterostructure demonstrates the synergistic effect on the dimensional, interface, surface structures and compositions, resulting from the ordered and functionalized architectures. Therefore, the NiMoO4@C@Ni3S2 electrode integrated the advantages of the electron transfer, electrolyte penetration and ion diffusion. The asymmetric supercapacitor exhibited a high energy density of 1.29 mW h cm−3 at a power density of 13.99 W cm−3. Furthermore, we compared the changes in composition, structure and morphology before and after 3000 cycles using the three electrode system. These observations demonstrated that the dissolution of NiMoO4@C@Ni3S2 induced the decay of capacitance and cycling stability, suggesting that we can further develop a strategy to consolidate the electrode structure.