A High-Performance Nanoflower MnCo <sub>2</sub> O <sub>4</sub> /ZnCo Layered Double Hydroxide Electrode Supported on Ni Foil for Advanced Asymmetric Supercapacitors
Rohini Sankannavar, Omkar Kulkarni, Tabbu Shaikh, Sanjay S. Kolekar, Jin Hyeok Kim, J. Manjanna
Abstract
Combining metal oxides with layered double hydroxides (LDHs) makes a unique approach to produce new nanomaterials for energy storage applications viable. The MnCo 2 O 4 /ZnCo LDH nanoflowers are grown using a two-step hydrothermal and reflux condensation technique on the inexpensive, readily available substrate nickel foil (Ni foil). The advantageous structure of the electrode provides a high surface area, which is beneficial for improved electrochemical performance through a synergistic effect in the MnCo 2 O 4 /ZnCo LDH electrode. From the optimized condition in the three-electrode system, the electrode exhibits a specific capacitance of 1253.3 F g –1 at a current density of 15 mA cm –2 and greater stability. By using MnCo 2 O 4 /ZnCo LDH as a positive electrode and activated carbon (AC) as a negative electrode, an amazing solid-state asymmetric supercapacitor device is developed. The device possesses an energy density of 55.9 Wh kg –1, power density of 5.2 kW kg –1, and cyclic stability of 87.67% retention after 5000 cycles. With excellent performance, our study offers a new platform for the electrochemical application of nanoflower MnCo 2 O 4 /ZnCo LDH.