Designing nanosheet manganese cobaltate@manganese cobaltate nanosheet arrays as a battery-type electrode material towards high-performance supercapacitors

Abstract Binder-free hierarchical nanosheet manganese cobaltate@manganese cobaltate nanosheet arrays (NS MnCo2O4@MnCo2O4 NSAs) heterostructures have been successfully deposited on nickel (Ni) foam surface using a facile two-step hydrothermal process. Scanning electron microscope characterization illustrate that the as-developed composite exhibits a growth of smaller MnCo2O4 nanosheet structures anchored on the surface of MnCo2O4 NSAs that provide abundant reactive sites and effective electronic transmission, endowing the NS MnCo2O4@MnCo2O4 NSAs an outstanding electrochemical performance. The electrochemical measurements reveal that the as-prepared NS MnCo2O4@MnCo2O4 NSAs delivers a Faradic battery-type redox behavior, which is distinct from the behaviors of carbon-based materials. As a battery-type material, NS MnCo2O4@MnCo2O4 NSAs exhibits an outstanding specific capacity (135.15 mA h g−1 at 2 A g−1) and remarkable rate capability (82.93%), which are much higher than that of bare MnCo2O4 NSAs. Moreover, NS MnCo2O4@MnCo2O4 NSAs delivers an excellent cycling stability of 88.74% over 5000 cycles. Hence, these electrochemical results suggest that the as-developed NS MnCo2O4@MnCo2O4 NSAs can serve as an advanced battery-type electrode material for supercapacitor applications.