Oxygen content：the key role enabling phase transition during calcination of sodium layered oxides cathode

Abstract

Abstract Considering the non-stoichiometric feature of sodium layered oxides cathode, oxygen content in the calcination atmosphere would play a key role in the phase evolution, which is still unclear and deserves detailed investigation. In the present study, with the controlled oxygen content via under different atmospheres, structural oxygen release driven by heating was evidenced to be the phase transition trigger, which destroy the initial local Mn-O structure and results in rearranged Mn-O octahedral ordered structure. The varied oxygen content would change the star-up temperature of phase transition. These results can promote the materials phase design by adjusting the release of structural oxygen and provide guideline for the synthesis of layered oxides.