Effect of lanthanum dopant on the structural and electrical properties of LiCoVO4 cathode materials investigated by EXAFS

The effect of lanthanum dopant on the structural and electrical properties of LiCoVO4 cathode materials was investigated by X-ray absorption spectroscopy (XAS). The conductivity of LiCoVO4 was increased from 8.44×10−9 to 7.17×10−8 S/cm by doping proper amounts of La2O3. The doping of La results in slightly decreasing the oxidation states of Co and V and the intensity of Fourier transform (FT) around absorbing atom Co and V. It may result from the distortion of the inverse spinel structure of LiCoVO4. It was suggested that La dopant located in interstitial site near vanadium atom to make the tetragonal distortion. This distortion is contributed to the generation of the defects in the doped LiCoO4 and the enhancement of its conductivity.