Lithium Storage Using Conversion Reaction in Maghemite and Hematite

We report here on the lithium storage performance of α- and , undergoing conversion reaction at C/10 and 2C. Both α- and transform to nanostructured composite during the first discharge, while the first charge results in the formation of nanosized . Such a transition from to is attributed to its thermodynamics at the nanosize. Better storage performance of at 2C compared with is attributed to the formation of highly crystalline, nanosized . Apart from the reported inherent electronic conductivity of , the thermodynamics at the nanosize is also found to be one of the rate-limiting factors.