Diffusional mechanism of deintercalation in LiFe1−yMnyPO4 cathode material

The paper presents the investigations on the structural, electrical and electrochemical properties of Mn substituted phospho-olivines LiFe1 − yMnyPO4 and of W, Ti or Al doped LiFePO4. The microscopic nature of the observed macroscopic, metallic-like conductivity of W, Ti, Al doped phospho-olivine samples is discussed. Some fundamental arguments against the bulk type conductivity are presented. A single phase, diffusional mechanism of deintercalation was found to appear for Mn-substituted LiFe1 − yMnyPO4 samples in the whole range of lithium concentration, in contrast to the pure LiFePO4, LiMnPO4 and W, Ti, Al doped phospho-olivines, where a two-phase mechanism of electrochemical lithium extraction/insertion is observed.