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Electrode material–ionic liquid coupling for electrochemical energy storage

Abstract

The development of new electrolyte and electrode designs and compositions has led to advances in electrochemical energy-storage (EES) devices over the past decade. However, focusing on either the electrode or electrolyte separately is insufficient for developing safer and more efficient EES devices in various working environments, as the energy-storage ability is determined by the ion arrangement and charge and/or electron transfer at the electrode–electrolyte interface. In this Review, we assess the fundamental physicochemical and electrochemical properties at the electrode–electrolyte interfaces in Li-ion batteries and supercapacitors using safe and electrochemically stable ionic-liquid electrolytes. Key reactions and interactions at the electrode–electrolyte interface, as well as geometric constraints and temperature effects, are highlighted. Building on the fundamental understanding of interfacial processes, we suggest potential strategies for designing stable and efficient ionic-liquid-based EES devices with emerging electrode materials.

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Fig. 1: Ionic-liquid electrolytes for electrochemical energy-storage devices.
Fig. 2: Ionic-liquid ions and properties of ionic-liquid mixtures.
Fig. 3: Structure of the ionic liquid–electrode interface.
Fig. 4: Interfacial reactions.
Fig. 5: Ion transport and charge-storage capability.
Fig. 6: New electrolyte–electrode interfaces.

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Acknowledgements

This research was sponsored, in part, by the Fluid Interface Reactions, Structures and Transport (FIRST) Center, an Energy Frontier Research Center funded by the US Department of Energy, Office of Science and Office of Basic Energy Sciences. The work of M.S., J.C.V. and M.W.G. at Boston University was supported by Samsung Electronics Co. (Samsung Advanced Institute of Technology, SAIT). The authors also acknowledge K. Van Aken, A. Levitt and X. Lin for helpful discussions.

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All authors discussed the content and contributed to the editing of the manuscript prior to submission. X.W. wrote the manuscript under the supervision of Y.G. and M.W.G. X.W. and M.S. researched data for the article. M.S., J.C.V. and S.D. contributed to the section on the properties of ionic liquids. D.-e.J. contributed to the theory section. D.J.W. contributed insight relating to ionic liquid–electrode interfacial structures and local dynamics. X.W., M.S., J.C.V. and B.A. contributed to the figures.

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Correspondence to Mark W. Grinstaff or Yury Gogotsi.

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Wang, X., Salari, M., Jiang, De. et al. Electrode material–ionic liquid coupling for electrochemical energy storage. Nat Rev Mater 5, 787–808 (2020). https://doi.org/10.1038/s41578-020-0218-9

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