The Synthesis of ZnMn2O4 by Glycine Nitrate Combustion and an Examination of Its Electrochemical Properties in Aqueous Solutions of ZnCl2 and NaNO3

Abstract

To research potential replacements for LiMn2O4, this work carries out a synthesis of ZnMn2O4 (ZMO) through the glycine-nitrate combustion. XRPD validates its phase characterization; electron microscopy confirmed the presence of single phase ZMO in the form of curvy and rod-shaped sub-micron sized particles at an average of 113 nm. This work is novel for its electrochemical measurements of ZMO as a cathodic material for alkali-ion batteries, performed by cyclic voltammetry in aqueous solutions of ZnCl2 and NaNO3 ranging from 5 to 100 mV s–1 polarization rates, yielding stable capacities for both electrolytes. The highest capacities were obtained for the polarization speed of 5 mV s–1 for both electrolytes. Their cathode capacities were 11.3 and 27.2 mA h g–1 for ZnCl2 and NaNO3, respectively. Concerning Na-ions batteries, the surface storage is the deciding factor due to the adsorption of Na+ ions on the λ-MnO2 phase. Unlike Znions, Na+ ions cannot intercalate into the spinel structured materials.