Joule
ArticleCycling mechanism of Li2MnO3: Li–CO2 batteries and commonality on oxygen redox in cathode materials
Context & scale
In the debates on how to achieve high energy density battery cathodes, Li-rich compounds are often considered superior over conventional materials due to their high capacity associated with the oxygen redox reactions. Here, we clarify both the bulk and surface reaction mechanisms of Li2MnO3 during the initial and later cycles. Our results reveal that the initial charge plateau is from two types of surface activities, followed by predominating Mn redox reactions with no sign of reversible lattice oxygen redox. The surface chemistry of Li2MnO3 indicates a highly reactive surface to facilitate carbonate formation and decomposition, inspiring a Li-CO2/air battery with Li2MnO3 as a superior electrocatalyst. The comparison between Li-rich, conventional, and Li2MnO3 suggests that the oxygen redox in Li-rich and conventional materials is of the same nature and origin.