Investigation of Electronic Conductivity and Occupancy Sites of Mo Doped into LiFePO₄ by ab Initio Calculation and X-ray Absorption Spectroscopy

Abstract

Mo-doped LiFePO 4 composite was synthesized by the solid state method, using (NH 4 ) 6 Mo 7 O 24 ·4H 2 O as the starting doping material. The electrochemical properties of Mo-doped LiFePO 4 were measured. The electronic structures of Mo-doped LiFePO 4 were studied by ab initio calculations. With respect to the density of states (DOS) of the LiFePO 4, in which no electronic states are at the Fermi level, the Mo doping is predicted largely impacting the conductivity. Experimental data of the electronic conductivity and of the electrochemical performance of Mo-doped LiFePO 4 synthesized by a solid state reaction confirm the results of the calculations. To characterize the doped LiFePO 4 structure and the type and the symmetry of the Mo sites, X-ray absorption spectroscopy (XAS) experiments were performed.