Core-shell structured CuCo2S4@CoMoO4 nanorods for advanced electrode materials

Transition metal oxides and sulfides exhibit excellent electrochemical properties owing to their various valence states, high electrical conductivities, large number of active sites, and superior electrochemical activities. In this study, core-shell structured CuCo2S4@CoMoO4 nanorods were prepared on nickel foam via the combination of the hydrothermal method and calcination. The CuCo2S4@CoMoO4 heterostructure shows improved electrochemical performance. The CuCo2S4 nanorods provided channels for rapid electron transport and effectively dispersed CoMoO4 particles, while the outer CoMoO4 shell inhibited the expansion of the inner CuCo2S4 nanorods during the redox reaction and increased the stability of the produced composite. The electrode fabricated from the CuCo2S4@CoMoO4 nanorod array grown on nickel foam possessed a high specific capacitance of 2058 F g−1 (5557 mF cm−2) at 1 mA cm−2. The asymmetrical supercapacitor formed after the addition of an activated carbon negative electrode demonstrated a high energy density of 45.73 W h kg−1 at a power density of 198.8 W kg−1. Further, it exhibited an outstanding cycling stability that corresponded to 83% specific capacitance retention after 3000 charge-discharge cycles. Illustration of the synthesis of CuCo2S4@CoMoO4 nanorod array on the NF substrate. [Display omitted] •CuCo2S4@CoMoO4 core-shell nanorod was synthesized by a facile way via hydrothermal reaction, vulcanization and calcination.•CuCo2S4@CoMoO4 composites delivers an ultrahigh specific capacitance of 2058 F g−1 at 1 mA cm−2.•The introduction of Cu in CuCo2S4@CoMoO4 can effectively control the core-shell nanorod morphology.•The fabricated ASC device achieved a maximum energy density of 45.73 Wh kg−1 at a power density of 198.8 W kg−1.