Crystal and electronic structures of lithium fluorosulphate based materials for lithium-ion batteries

By means of ab initio calculations, we study the electronic structure of LiFeSO₄F, which has been shown recently [N. Recham et al., Nature Mater. 9, 68 (2010)] to be an excellent material as a cathode for lithium-ion batteries. We have obtained the crystal structure of FeSO₄F, which was not completely determined experimentally, and compare the one of LiFeSO₄F to available experimental values, resolving the issue about the position of the Li ion. Our calculated intercalation voltage (3.69 V) is found to be in excellent agreement with experiments. Finally, we have studied LiCoSO₄F and LiNiSO₄F, which are found to share a similar crystal structure with LiFeSO₄F.