Plumage-like MnO2@NiCo2O4 core–shell architectures for high-efficiency energy storage: the synergistic effect of ultralong MnO2 “scaffold” and ultrathin NiCo2O4 “fluff”

Abstract

Here, we proposed a rational design of a plumage-like MnO2@NiCo2O4 core–shell architecture by a mild hydrothermal and chemical bath deposition method. The hierarchical structure comprises the stable “scaffold” of the MnO2 nanowires and the high-activity “fluff” of ultrathin NiCo2O4 nanosheets. Besides, considering the cost of nickel and cobalt elements, the content of NiCo2O4 was controlled within 50% in our design. The ideal MnO2@NiCo2O4-8h electrode achieved remarkable electrochemical performances with high specific capacity of 618.0 C g−1 at 1 A g−1, outstanding rate capability of 89% from 1 to 10 A g−1, and superior cycling stability of 71% after 5000 cycles. Furthermore, the synergy capacitance was also evaluated to be 360.7 C g−1 with a synergy efficiency of 58%. The smart design is suitable for constructing advanced electrode material for high-performance supercapacitor.