Low temperature synthesis and electrochemical performance of crystallized FeVO4·1.1H2O

A wet synthesis method, which consists in a precipitation reaction occurring without pH control, is described to obtain a hydrated crystallized iron orthovanadate. Both reaction time and temperature parameters were used to reach the thermodynamic equilibrium formation conditions of FeVO4·1.1H2O. By means of several characterization techniques this compound was identified as similar to the fervanite mineral Fe4V4O16·5H2O. Like the other iron-based orthovanadates, this fervanite-type phase displays unusual electrochemical properties with respect to Li acceptance/removal at low average voltages. From the electrochemical data collected on the artificial fervanite and its dehydrated products, a linear correlation between the material water content and its electrochemical performances, namely in terms of irreversible and reversible capacities, has been found.