Competition between the Ni and Fe Redox in the O3-NaNi1/3Fe1/3Mn1/3O2 Cathode Material for Na-Ion Batteries

Shevchenko, V.A.; Glazkova, I.S.; Novichkov, D.A.; Skvortsova, I.; Sobolev, A.V.; Abakumov, A.M.; Presniakov, I.A.; Drozhzhin, O.A.; Antipov, E.V.

Авторы: Shevchenko Vitalii A., Glazkova Iana S., Novichkov Daniil A., Skvortsova Irina, Sobolev Alexey V., Abakumov Artem M., Presniakov Igor A., Drozhzhin Oleg A., Antipov Evgeny V.
Журнал: Chemistry of Materials
Год издания: 2023
Издательство: American Chemical Society
Местоположение издательства: United States
DOI: 10.1021/acs.chemmater.3c00338
Аннотация: Sodium-ion batteries are attracting great attention due to their low cost and abundance of sodium. The O3-type NaNi1/3Fe1/3Mn1/3O2 layered oxide material is a promising candidate for positive electrodes (cathodes) in Na-ion batteries. However, its stable electrochemical performance is restricted by the upper voltage limit of 4.0 V (vs Na/Na+), which allows for reversibly removing 0.5–0.55 Na+ per formula unit, corresponding to the capacity of 120–130 mAh·g–1. Further reduction of sodium content inevitably accelerates capacity degradation, and this issue calls for a detailed study of the redox reactions that accompany the electrochemical (de)intercalation of a large amount of sodium. Here, we present operando and ex situ studies using powder X-ray diffraction and X-ray absorption spectroscopy combined with 57Fe Mössbauer spectroscopy. Our approach reveals the sequence of the redox transitions that occur during the charge and discharge of O3-NaNi1/3Fe1/3Mn1/3O2. Our data show that in addition to nickel and iron cations oxidizing to M+4, a part of iron transforms into the “3 + δ” state owing to the fast electron exchange Fe3+ + Fe4+ ↔ Fe4+ + Fe3+. This process freezes upon cooling the material to 35 K, producing Fe4+ cations, some of which occupy tetrahedral positions.
Добавил в систему: Соболев Алексей Валерьевич

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Competition between the Ni and Fe Redox in the O3-NaNi1/3Fe1/3Mn1/3O2 Cathode Material for Na-Ion Batteriesстатья

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