Chemical delithiation and exfoliation of LixCoO2

Progressive chemical delithiation of commercially available lithium cobalt oxide (LiCoO2) showed consecutive changes in the crystal properties. Rietveld refinement of high resolution X-ray and neutron diffraction revealed an increased lattice parameter c and a reduced lattice parameter a for chemically delithiated samples. Using electron microscopy we have also followed the changes in the texture of the samples towards what we have found is a critical layer stoichiometry of about LixCoO2 with x=1/3 that causes the grains to exfoliate. The pattern of etches by delithiation suggests that unrelieved strain fields may produce chemical activity. (C) 2014 The Authors. Published by Elsevier Inc.