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Multi‐Electron Reactions Enabled by Anion‐Based Redox Chemistry for High‐Energy Multivalent Rechargeable Batteries
Author(s) -
Li Zhenyou,
Vinayan Bhaghavathi P.,
Jankowski Piotr,
Njel Christian,
Roy Ananyo,
Vegge Tejs,
Maibach Julia,
Lastra Juan Maria García,
Fichtner Maximilian,
ZhaoKarger Zhirong
Publication year - 2020
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.202002560
Subject(s) - redox , chemistry , cathode , ion , electron transfer , battery (electricity) , cationic polymerization , inorganic chemistry , photochemistry , thermodynamics , organic chemistry , power (physics) , physics
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 VS 4 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 Mg 2+ ion diffusion kinetics enabled by the soft structure and flexible electron configuration of VS 4 .