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Multi‐Electron Reactions enabled by Anion‐Based Redox Chemistry for High‐Energy Multivalent Rechargeable Batteries [in press]

Li, Zhenyou; Vinayan, Bhaghavathi P.; Jankowski, Piotr; Njel, Christian; Roy, Ananyo; Vegge, Tejs; Maibach, Julia; Lastra, Juan Maria García; Fichtner, Maximilian; Zhao‐Karger, Zhirong

Abstract:
The development of multivalent metal (such as Mg and Ca) based battery systems is hindered by lack of suitable cathode chemistry that shows reversible multi‐electron redox reactions. Cationic redox centres in the classical cathodes can only afford stepwise single‐electron transfer, which are not ideal for multivalent‐ion storage. The charge imbalance during multivalent ion insertion might lead to an additional kinetic barrier for ion mobility. Therefore, multivalent battery cathodes only exhibit slope‐like voltage profiles with insertion/extraction redox of less than one electron. Taking VS4 as a model material, reversible two‐electron redox with cationic–anionic contributions is verified in both rechargeable Mg batteries (RMBs) and rechargeable Ca batteries (RCBs). The corresponding cells exhibit high capacities of >300 mAh g−1 at a current density of 100 mA g−1 in both RMBs and RCBs, resulting in a high energy density of >300 Wh kg−1 for RMBs and >500 Wh kg−1 for RCBs. Mechanistic studies reveal a unique redox activity mainly at anionic sulfides moieties and fast Mg2+ ion diffusion kinetics enabled by the soft structure and flexible electron configuration of VS4.

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Originalveröffentlichung
DOI: 10.1002/anie.202002560
Zugehörige Institution(en) am KIT Institut für Angewandte Materialien - Energiespeichersysteme (IAM-ESS)
Helmholtz-Institut Ulm (HIU)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2020
Sprache Englisch
Identifikator ISSN: 1433-7851, 1521-3773
KITopen-ID: 1000119461
Erschienen in Angewandte Chemie / International edition
Vorab online veröffentlicht am 08.05.2020
Nachgewiesen in Web of Science
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