Insight on morphology structure and electrochemical performance of P2-Na_0.67Fe_0.5Mn_0.5O₂ layered oxide cathode material

Sodium-ion batteries have received widespread attention for the large-scale energy storage systems due to the abundant sodium source. The P2-Na_0.67Fe_0.5Mn_0.5O₂ cathode material is a promising energy storage candidate because of its high theoretical capacity and low cost. In this work, the relationship of morphology and electrochemical performances of P2-Na_0.67Fe_0.5Mn_0.5O₂ cathode materials were investigated by controlling solid-state synthesis method and using scanning electron microscope and multiple electrochemical tests. The impacts for the morphology and structure of the cathode are investigated by controlling high-temperature calcination process to illustrate the heterogeneous phase mechanism and the electrochemical performances improvement. The results show that the morphology and structure are more uniform and integrated at the calcination temperature of 900 °C after pre-calcination, with moderate and uniform particle size, and the increase of temperature promotes the atomic rearrangement in the solid-phase reaction. It was also observed that the material in the compacted state showed smooth particles with uniform particle size and a more complete crystal structure, as well as improved specific capacity. It is exhibited an initial discharge specific capacity of 161.35 mAh/g, while the cycling performance was slightly inferior to than that of the uncompacted sample.