Facile synthesis of CoFe2O4 powders for aqueous charge storage

Abstract

In this work, the electrochemical performance of CoFe2O4 powders was improved by selecting a proper organic fuel (glycine, urea, and citric acid) for the solution combustion synthesis method. Burning the glycine fuel led to the higher crystallinity, larger particle size, and spongy microstructure of the CoFe2O4 powders, caused by its high combustion temperature and combustion rate. In contrast, the urea and citric acid fuels resulted in the higher specific surface areas of 57 and 47 m2/g, respectively, than that of 23 m2/g for the glycine fuel due to the lower combustion temperature. The glycine-assisted CoFe2O4 powders exhibited high electrochemical performance, including high specific capacitances of 718 and 446 Fg-1 at the current densities of 1 and 20 Ag-1, respectively. Furthermore, the asymmetric aqueous capacitor of CoFe2O4//activated carbon electrochemically stores energy density of 42 Wh kg-1 for the potential window of 0-1.5 V.