Development of Cathode Materials Adding Excess LiF with High Interfacial Concentration

The nanocomposite cathode materials with high interfacial concentration such as xLiF–LiCrO2 and xLiF–FeSO4 were investigated to improve the rechargeable capacities. These nanocomposites can be easily obtained using a dry ball-milling method. The obtained LiF-excess nanocomposite cathodes showed the larger rechargeable capacity and reducing overpotential than the prepared nanocomposite as chemical composition (LiCrO2 or LiFeSO4F). It is considered that the Li diffusion in the obtained nanocomposites was improved by preparing a locally Li-rich environment. Although the LiF–LiCrO2 nanocomposite has poor cyclability, this cathode had the high energy density of over 700 Wh kg−1. The nanocomposites, which easily obtained using a ball-milling method, can be expected to move away from the conventional cathode materials research using only crystalline materials and become one of the new concepts for cathode material research.