Anionic Redox Reaction in Li ‐Excess High‐Capacity Transition‐Metal Oxides

Dependence on Li-ion batteries for automobile applications is rapidly increasing, and further development of positive electrode materials is indispensable to increase the energy density of Li-ion batteries. In the past several years, many new Li-excess high-capacity electrode materials with rocksalt-related structures have been reported. These materials deliver high reversible capacity with cationic/anionic redox and percolative Li migration in the oxide/oxyfluoride framework structures, and recent research progresses on these electrode materials are summarized. Material design strategies for the stoichiometric and Li-excess electrode materials are also described. Future possibility of high-energy batteries with advanced positive electrode materials is discussed in detail.