Revisiting the Na2/3Ni1/3Mn2/3O2 Cathode: Oxygen Redox Chemistry and Oxygen Release Suppression.

ABSTRACT: Sodium layered transition metal oxides have been considered as promising cathode materials for sodium ion batteries due to their large capacity and high operating voltage. However, mechanism investigations of chemical evolution and capacity failure at high voltage are inadequate. As a representative cathode, Na2/3Ni1/3Mn2/3O2, the capacity contribution at a 4.2 V plateau has long been assigned to the redox of the Ni3+/Ni4+ couple, while at the same time it suffers large irreversible capacity loss during the initial discharging process. In this work, we prove that the capacity at the 4.2 V plateau is contributed to the irreversible O2-/O2 n-/O2 evolution based on in situ differential electrochemical mass spectrometry and density functional theory calculation results. Besides, a phenomenon o

SUBMITTER: Zhang Y 

PROVIDER: S-EPMC7047265 | biostudies-literature | 2020 Feb

REPOSITORIES: biostudies-literature