The Sodium Storage Mechanism in Tunnel-Type Na0.44MnO2 Cathodes and the Way to Ensure Their Durable Operation

Munseok S. Chae, Hyojeong J. Kim, Hyeri Bu, Jeyne Lyoo, Ran Attias, Ben Dlugatch, Matan Oliel, Yosef Gofer, Seung Tae Hong, Doron Aurbach

Research output: Contribution to journalArticlepeer-review

57 Scopus citations

Abstract

Tunnel-type sodium manganese oxide is a promising cathode material for aqueous/nonaqueous sodium-ion batteries, however its storage mechanism is not fully understood, in part due to the complicated sodium intercalation process. In addition, low cyclability due to manganese dissolution has limited its practical application in rechargeable batteries. Here, the intricate sodium intercalation mechanism of Na0.44MnO2 is revealed by combination of electrochemical characterization, structure determination from powder X-ray diffraction data, 3D bond valence difference maps, and barrier-energy calculations of the sodium diffusion. NaI is proposed as an important electrolyte solution additive. It is shown to form a thin, beneficial, and durable cathode surface film that prevents manganese dissolution. The addition of 0.01 m NaI to electrolyte solutions based on alkyl carbonate solvents and NaClO4 greatly improves the cycling efficiency, raising the capacity retention from 86% to 96% after 600 cycles. This study determines the core aspects of the sodium intercalation mechanism in tunnel-type sodium manganese oxide and shows how it can serve as a durable cathode material for rechargeable Na batteries.

Original languageEnglish
Article number2000564
JournalAdvanced Energy Materials
Volume10
Issue number21
DOIs
StatePublished - 1 Jun 2020

Bibliographical note

Publisher Copyright:
© 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Funding

This work was partially supported by the Ministry of Energy of Israel. This work was partially supported by the Ministry of Energy of Israel.

FundersFunder number
Ministry of Energy of Israel
Ministry of Energy, Israel

    Keywords

    • cathode surface films
    • electrolyte solutions additives
    • sodium intercalation
    • sodium-ion batteries
    • tunnel-type sodium manganese oxide

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