Quality control of Li1 + δMn2 − δO4 spinels with their impurity phases by Jaeger and Vetter titration

Powders of lithium manganese oxide phases are synthesised and characterised for possible application in a Li-ion battery. A modified phase diagram on the basis of the manganese oxidation state and content is used to interpret the results. X-ray diffraction, flame atomic absorption spectroscopy, and Jaeger and Vetter titration are performed in order to classify the synthesised powders. The experiments reveal powders of Li1 + δMn2 − δO4 (0 < δ < 0.2, i.e. 0 < Li/Mn < 0.65), with a spinel structure. At higher Li/Mn ratios mixtures of Li1.2Mn1.8O4 and Li2MnO3 are formed. Spinels with small δ-values are favoured since they are more stable than the pure LiMn2O4, but they have still acceptable capacity. Also, aluminium-doped spinel materials with the composition Li1 + δAlnMn2 − δ − nO4 (0 < n < 0.3, δ = 0.0645) are synthesised and characterised. However, no improvement in terms of capacity is found.