Microwave-Assisted Hydrothermal Synthesis of MnO/C Composite in the Presence of Ascorbic Acid

Abstract

Composites MnO/C based on cubic manganese monoxide were synthesized by microwave-assisted hydrothermal treatment of an aqueous solution of potassium permanganate with ascorbic acid and subsequent annealing of the precursor in an inert atmosphere at a temperature of 500°C. It was found that the molar ratio of the reaction mixture components, Mn : C₆H₈O₆ = 1 : (0.75‒1.5), is the key parameter determining the features of composite formation. A mechanism of formation of the MnO/C composite was proposed. The maximum carbon content in the composite material was ~3 wt %. The main physicochemical characteristics of the synthesized composites were determined using powder X-ray diffraction, thermogravimetric analysis, Raman spectroscopy, scanning electron microscopy, and low-temperature nitrogen adsorption. The behavior of MnO/C as an anode material for a lithium-ion battery showed that the composite is efficient only at high current densities.