P2-Na2/3Mg1/4Mn7/12Co1/6O2 cathode material based on oxygen redox activity with improved first-cycle voltage hysteresis

[摘要] The recent report of P2-Na2/3Mg0.28Mn0.72O2 (P2-NMM) demonstrated the possibility of utilizing the oxygen redox couple in a layered oxide cathode without the need for alkali ions or vacancies in the transition metal layer. In this work, we report the synthesis of a new P2-type compound, Na2/3Mg1/4Mn7/12Co1/6O2 (P2-NMMC), which exhibits reversible specific capacities as high as 173 mAh g(-1) and an improvement of the first cycle voltage hysteresis over P2-NMM. The material was characterised using a combination of ex-situ and operando techniques including X-ray diffraction (XRD), differential electrochemical mass spectrometry (DEMS) and X-ray spectroscopy (XAS) to identify potential sources for this improvement.

[发布日期] 2021-09-15