Sodium de-insertion processes in single NaxTMO2 particles studied by an electrochemical collision method: O3 phases versus P2 phases

An electrochemical collision method is utilized to compare the sodium de-insertion process in particles of quarternary sodium-containing layered metal oxides Na x TMO 2 (TM = Fe, Mn, Ni, Cu) in the O3 phase and the P2 phase. The electrochemical behavior of the two types of materials is found to be different. The diffusion of Na + inside an individual particle occurs more readily in O3-type oxides than in P2-type oxides, which is contrary to the conventional wisdom that P2-type oxides usually provide higher Na-ion conductivity than their O3 analogs. These results provide a more detailed analytical perspective for assessing battery materials.