Defect Structure of LiMn₂O₄ after High-Temperature Storage

Abstract

A novel Rietveld analytical method for neutron diffraction data was developed with internal Si standard to adjust the scale factor and led to the accurate defective structure of lithium manganese spinel cathode after high temperature storage. An abrupt decrease of the site occupancies for all elements, g(Li), g(Mn) and g(O), was confirmed at the temperature range above 50°C, together with the corresponding shrinkage in the unit-cell volume. This supports the degradation model that the host atoms in bulk migrate to the particle surfaces to cause charge disproportionation.