Site selectivity in doped polyanion cathode materials for Li-Ion batteries

We propose a simple and effective method to determine the occupancy preference of cations doped in polyanion cathode materials for Li-ion batteries based on ionic electronegativity and ionic radius. The occupancy site can be predicted by comparing the combined deviation degree of electronegativity and radius between the dopant and the substituted ion, and dopants prefer to occupy the site where the deviation degree is less. Based on this method, we predicted the preferred occupancy sites of 38 frequently used ions doped in LiFePO4 and Li3V2(PO4)(3), which can be in accordance with the available experimental and other calculated results. This simple method established in current work can serve as an effective tool to well predict the preferred occupancy sites of cations doped in cathode materials, which can provide powerful guidance in designing cathode materials for high-performance Li-ion batteries.