LAUSR

Abstract A new model material of Na0.6[Mg(II)0.3Mn(IV)0.7]O2, with only Mg2+ and Mn4+ in the transition metal layers, is synthesized for the research of anionic redox reaction. The material delivers a capacity of ∼130 mAh/g with a long plateau at ∼4.2 V in the initial charge profile, indicating anionic redox reaction (ARR) involved during the initial desodiation process. In the following cycles, the reversible capacity can reach a high value of ∼210 mAh/g, which is probably derived from the participation of both ARR and Mn3+/Mn4+ redox couples, further proving the charge compensation from ARR during the initial charge and following cycles. The designed cathode material without Mn3+ helps avoid the influence of oxygen activity from transition metals, enabling the investigation of ARR without other distractions.