Nickel manganite-carbonized alginate composite for use as energy storage electrodes

Abstract

Nickel-manganite is a versatile material used in many technology applications. One of the established uses is as a supercapacitor electrode. The advantage of this type of material is the abundance of required metals, compared to noble metals, the synthesis methods' simplicity, and high redox activity. Metal-oxide battery materials are usually combined with activated carbon to enhance the specific surface area and add to energy storage capacity via surface charge accumulation. In the current work, nickel manganite was synthesized via the sol-gel combustion synthesis method with glycine as fuel and nitrate ions as oxidizers. The post-combustion amorphous powder was calcined at temperatures between 300 and 800 °C. Powders were structurally characterized. Obtained materials were tested as energy storage electrodes in a three-electrode cell setup in 6 M KOH aqueous solution as electrolyte. Methods embedded in electrochemical characterization were cyclic voltammetry (CV), electric impedance spectroscopy (EIS) and constant current chronopotentiometry at different current densities to obtain galvanostatic charge-discharge (GCD) curves. Results show considerable charge storage activity, which can be ascribed to oxido reduction reactions of manganese ions and charge accumulation on the surface of the activated carbon.