Since the discovery by Thackeray and co-workers of their ability to reversibly intercalate Li, spinel oxides in the family LiM2O4 (M=Mn, Ni, Co...) have become a canonical electrode material in Li-ion battery systems. Phases with this structure typically present very stable cycle life in the bulk and fast kinetics. The best performance is obtained with significant amounts of Mn in the structure, yet the presence of Ni creates opportunities to raise the voltage of the final cell, which increases energy density. When used as positive electrodes, the downside of spinel electrodes is their fairly low capacity and their interfacial instability. Further, while full intercalation from M2O4 to Li2M2O4 is possible, it is also poorly reversible. As a result, practical applications limit the utilization to processes between M2O4 and LiM2O4. All in all, this class of materials epitomize the existing scientific barriers in battery research, such as long term stability and two electron reactivity. In this talk, an overview will be presented of the understanding we have developed of mechanisms that control the performance spinel oxides as reversible battery electrodes, and the subsequent strategies we have followed to expand their versatility. This overview will cover phenomena from interfaces to electrodes, and explore the possibility of using spinel oxides in multivalent systems.

Tale of spinels: From Li-Ion to Mg battery electrodes

253rd National Meeting (2017)

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