First principles studies on the electronic structures of LiM_xFe_1-xPO₄ (M=Co, Ni and Rh)

The local crystal structures and electronic structures of LiM_xFe_1-xPO₄ (M = Co, Ni, Rh) are studied through first-principles calculations. The lattice constants and unit cell volumes are smaller for the Co and Ni doped materials than for pure LiFePO_4, while larger than for the Rh doped material. The local structures around M atoms in the doped materials are studied in details. The total density of states (DOS) and atomic projected DOS (PDOS) are all calculated and analysed in detail. The results give a reasonable prediction to the improvement of electronic conductivity through Fe-site doping in LiFePO₄ material.