Recent work on lithium manganate spinel oxides, which draw attention as positive active material of the next generation lithium secondary batteries, is briefly summarized. Poor cycling performance of LiMn{sub}2O{sub}4 can be substantially improved by substituting a part of the manganese with either chromium, cobalt or nickel, though the substitution with nickel entails a decrease in the capacity density. Results of the Rietveld analysis indicate that the improved cycleability is attributable to the stability of the spinel structure due to a shorter distance of Li-O and M-O as the result of the substitution. In addition, in differential scanning calorimetry when the sample is cooled, LiMn{sub}2O{sub}4 shows an exothermic peak associated with phase transition, but this can be prevented by the substitution with chromium.
展开▼
