High-Power Nanostructured LiMn2-xNixO4 High-Voltage Lithium-Ion Battery Electrode Materials:  Electrochemical Impact of Electronic Conductivity and Morphology

The direct relationship between the electronic conductivity of the nanostructured spinel LiMn2-xNixO4 and its lattice parameter is reported. Within the 8.167−8.183 Å range studied, there was a systematic 2.5 orders of magnitude difference between the highest electronic conductivity (cation disordered Fd3m spinel) to lowest conductivity (ordered P4332 spinel). The underlying reason behind the higher conductivity of the former was the presence of Mn3+ (nonexistent in ordered) and Mn4+ sites. The impact of the observed electronic conductivity on electrochemical performance is discussed with respect to morphological impact on ion diffusion and power delivery in various electrode formulations.