Conversion of Mined Copperas to Precursor Lithium Iron Phosphate of Battery Cathode

The project will explore routes to convert a waste stream of copperas (FeSO4.7H2O) for new purposes, for example LiFePO4 powders to prepare cathodes for batteries. While the methodology has been demonstrated for pure FeSO4.7H2O (Journal of Power Sources, 160, 516-522), understanding the role of process impurities in copperas and how they affect the properties of the material required for repurposing is to be explored.

The project will focus around three general areas: i) assessing the effect of impurities on the crystal structure of copperas. The structure is typically monoclinic, but studies have shown that impurities can produce more rhombic structures due to incorporation of the impurities into the crystal structure; ii) the physical (crystal structure, shape, porosity) and chemical (surface charge, functional groups) properties of the copperas (pure and impure) and cathode materials will be characterized, to determine how those properties govern the electrochemical performance of the prepared electrodes. This data will complement the crystal structure modelling and provide understanding of the role of impurities on the physicochemical properties of LiFePO4 powders; iii) develop routes to prepare LiFePO4 and how it can be adapted (surfactants, alcohol content) to improve the overall electrochemical performance, with robust performance testing of the material to be completed - voltage profiles and long-term cyclability.