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 spectrosc opy (XAS). The conductivity of LiCoVO4 was increased from 8.44 x 10(-9) to 7.17 x 10(-8) S/cm by doping proper amounts of La2O3. The doping of La resu lts in slightly decreasing the oxidation states of Co and V and the intensi ty of Fourier transform Fl around absorbing atom Co and V. It may result fr om the distortion of the inverse spinel structure of LiCoVO4. It was sugges ted 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 . (C) 2001 Elsevier Science B.V. All rights reserved.