Electrodeposition of nickel sulfide (Ni–S) on NiCo2O4 (NiCo2O4@Ni–S) nanoplate arrays produces a new hierarchical core–shell functional-material. Weak crystalline Ni–S nanosheets have been uniformly coated on the NiCo2O4 nanoplate array obtained by hydrothermal growth. When tested as an electrode for supercapacitors, the NiCo2O4@Ni–S nanoplate arrays have been found to exhibit a significantly improved areal capacitance of 1.85 F cm−2 at a current density of 8 mA cm−2, good rate capability and cycling stability. In addition, the capacitance fading of the NiCo2O4@Ni–S arrays are attributed to the surface coarsening of the Ni–S nanosheets.