A REINVESTIGATION OF THE STRUCTURES OF LITHIUM-COBALT-OXIDES WITH NEUTRON-DIFFRACTION DATA

The structures of LT-LiCoO2 (synthesised by reaction of Li2CO3 and CoC O3 at 400-degrees-C) and its delithiated product LT-Li0.4CoO2 have bee n reinvestigated by neutron powder diffraction. Despite an unusually c lose similarity between diffraction profiles that makes it difficult t o determine whether the structures are layered or spinel-like, the dat a confirm that the preferred structure of the LT-LiCoO2 sample made fo r this study is one that has a cobalt distribution which is intermedia te between an ideal layered and an ideal lithiated spinel structure. O n the other hand, refinement of the data of LT-Li0.4CoO2 prepared by r eacting LT-LiCoO2 with acid shows, unequivocally, that a spinel-type s tructure is formed. These structures are discussed in relation to prev iously reported electrochemical data obtained from Li/LT-LiCoO2 cells.