A study on the newly observed intermediate structures during the thermal decomposition of nickel-based layered cathode materials using time-resolved XRD

Time-resolved XRD analysis has been carried out to investigate structural changes of electrochemically delithiated nickel-based cathodes materials in the presence of electrolyte, when heated from 25 °C to 450 °C. A new structural change feature, the formation of an intermediate phase of Ni2O3 was observed at the same temperature as the NiO phase formation. It is believed that this intermediate structure plays an important role in the nickel cation reduction and oxygen release process during thermal decomposition of the cathode materials. It is found that the formation of this newly observed Ni2O3 phase is a general feature of the thermal decomposition for the nickel-base cathode materials.