Oxygen states in highly oxidized oxides: battery cathodes at high voltages

The high-voltage operation of a battery is highly desirable due to the high capacity and energy nature of performance. However, the electrochemical operation at high voltages of Alkali-ion batteries often drives the active cathode materials, which are transition metal oxide based, into an unusually high oxidation state. This triggers unconventional electronic configurations that are yet to be understood. In this presentation, we will discuss the importance of understanding and controlling the oxygen states in such highly oxidized oxide cathodes. We discuss the nature of the so-called oxygen redox (reduction and oxidation) state that strongly depends on transition metals, however, should be distinguished from the metal-oxygen hybridization itself. We try to specify a unified picture of the fundamental driving force, and provide guidelines for practical optimizations will be discussed.