Anionic Redox Reactions in Cathodes for Sodium‐Ion Batteries. Issue 4 (4th January 2021)

• Record Type: Journal Article
• Authors: Park, Jae‐Hyuk; Ko, In‐Hwan; Lee, Jaewoon; Park, Sangeon; Kim, Duho; Yu, Seung‐Ho; Sung, Yung‐Eun
• Is Part Of: ChemElectroChem. Volume 8:Issue 4(2021)
• Page Start: 625
• Page End: 643
• Publication Date: 2021-01-04
• Subjects: anionic redox -- energy storage -- sodium -- sodium-ion batteries -- transition metals; Electrochemistry -- Periodicals; 541.37
• DOI: 10.1002/celc.202001383
• Languages: English
• ISSNs: 2196-0216

Abstract

Abstract: Intercalation‐based cathodes typically rely on the cationic redox activity of transition metals to deliver capacity, but, recently, anionic redox chemistry has emerged as a way to increase the energy density of rechargeable batteries. However, the irreversible structural disorder and voltage fading accompanying oxygen release are major problems preventing commercial use. To overcome these limitations, the connection between structural stability and anionic redox activity must be understood. Here, we present a review of theoretical and experimental progress in anionic redox in sodium intercalation cathodes. First, the effects of structural factors including stacking sequences and cationic vacancies on the reversible capacity originating from anionic redox are discussed. Second, the effects on anionic redox activity of cationic substitution with alkaline earth metals (Li or Na) and the coordination environment are highlighted. Third, the progress and challenges facing materials based on 3 d/ 4 d/ 5 d metals are reviewed. Finally, research directions for the development of anionic redox active materials are outlined. Abstract : Capacity vs. stability : Recent investigations into anionic redox reactions in intercalation‐based positive electrodes, which represent a new paradigm for achieving high‐energy‐density rechargeable batteries, are reported. The focus of this Review is the application to sodium‐ion batteries, and methods to modify the material structure and electrochemical properties to achieve high‐capacity batteries with long cycle lives are also discussed.