Hydrothermal Microwave-Assisted Synthesis of Mn3O4/C Composite for Energy Conversion Devices

A composite based on manganese(II, III) oxide of the tetragonal modification Mn3O4/C was synthesized for the first time by hydrothermal–microwave treatment of a reaction mixture containing potassium permanganate and malic acid in a molar ratio of KMnO4 : C4H6O5 = 1 : 1. The carbon content in the composite material is ≈1.75 wt %. Using methods of X-ray phase and thermogravimetric analysis, Raman spectroscopy, scanning electron microscopy, and low-temperature nitrogen adsorption, the main physicochemical characteristics of Mn3O4/C were determined. The synthesized composite was studied as an electrode material for a pseudocapacitor and a lithium-ion power source. The specific capacitance of the Mn3O4/C-based pseudocapacitor electrode at a current density of 1 A/g reaches 205 F/g by the 2000th cycle. The discharge capacity of the Mn3O4/C anode material is 380 mA h/g after 100 cycles at a current density of 80 mA/g.