The defect structure model in nonstoichiometric LiMn2O4-delta

The defect model of nonstoichiometric spinel LiMn2O4-delta prepared under the control of oxygen partial pressures was determined by solid density measurement. There are two possible defect models. One is the oxygen deficient model, (Li)(8a)[Mn-2](16d)[O4-delta](32e) and the other the metal excess model, (Li)(8a)[Lidelta/(4-delta)][Mn2 delta/(4-delta)] (16d)[Mn-2](16d)[O-4](32e) model. It is expected that the solid density of the former model would decrease with increasing delta and that of the latter would increase with increasing delta. Since the observed density of the nonstoichiometric spinel actually increased, the metal excess model was supported for the nonstoichiometry.