Preparation of synthetic rutile and metal-doped LiFePO4 from ilmenite

The synthetic rutile and metal-doped LiFePO4 are prepared from the high-titanium residue and iron-rich lixivium, which are obtained from the ilmenite by a mechanical activation and leaching process. ICP results show that the rutile contains 92.01% TiO2, 1.59% Fe2O3, 0.034% MnO2 and 0.60% (MgO + CaO), which meet the requirement of the titanium dioxide chlorination process. The results also reveal that small amounts of Al3+, Ca2+ and Ti4+ precipitate in the FePO4·xH2O precursor. XRD and Rietveld-refine results show that the metal-doped LiFePO4 is single olivine-type phase and well crystallized, and Ti4+ occupy M1 site, Ca2+ occupy M2 site and Al3+ occupy both sites, which indicates the formation of cation-deficient solid solution. The sample exhibits a capacity of 123 mAh g−1 at 5C rate, and retains 94.3% of the capacity after 100 cycles.

Synthetic rutile and metal-doped LiFePO4 are prepared from ilmenite. XRD pattern (Fig. a, 4) reveals that the synthetic rutile is single phase and well crystallized. From the charge and discharge curves (Fig. b), the metal-doped LiFePO4 shows a capacity of 165, 163, 156, 141 and 123 mAh g−1 at 0.1C, 0.5C, 1C, 2C and 5C rate, respectively.Figure optionsDownload as PowerPoint slide