Temperature dependent local structure of LiCoO₂ nanoparticles determined by Co K-edge X-ray absorption fine structure

Temperature dependent Co K-edge extended X-ray absorption fine structure is used to investigate local disorder in LiCoO₂ nanoparticles. We find that the nanostructuring has direct influence on the bondlength characteristics. The results reveal a substantial decrease in the force constant of Co-O bonds (the Co-O bonds becoming more flexible), while that for the Co-Co bonds showing hardly any change (or increases slightly) in LiCoO₂ nanoparticles with respect to the bulk. Therefore, both random disorder and Co-O bondlength flexibility should be the factors to limit the battery characteristics of the LiCoO₂ nanoparticles.