Water-mediated super-correlated proton-assisted transport mode for solid-state K−O2 batteries

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Date
2024-09
Journal Title
Journal ISSN
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Publisher
Elsevier
Abstract
A comprehensive understanding of the behavior nature of fast ions at the atomic level is essential for the development of advanced solid-state ionic conductors. The inadequate inter-ion correlation effects of current ion transport models lead to a conductivity bottleneck in designing conductors. Herein, based on water-mediated proton-assisted ion transport, a novel transport mode with simultaneous anion-cation and inter-cation coupling is designed, enabling the K-ions of the modeled solid-state ionic conductor K2Fe4O7 crystals to achieve an ultra-high conductivity of 7.6 × 10–2 S cm–1, an enhancement of two orders of magnitude. The principle of the accelerated K-ion diffusion through the rotation and vibration of water molecules around the framework oxygen atom is elaborated, and the coupling correlation between proton and K-ion transport is confirmed using in-situ impedance spectroscopy under labeled isotopes. The application of this mechanism enabled the fabricated K−O2 solid-state battery exhibit an ultra-low overpotential (0.1 V) and excellent rate performance. Further, the mechanism is also applicable for Li and Na-ion conductors, providing significant theoretical guidance for breaking existing universal design rules and for the development for faster ionic conductors. © 2024 Elsevier B.V.
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Keywords
Ionic conductivity, Diffusion, Protons, Water, Electric batteries, Ions, Cations, Conductor devices, Spectroscopy
Citation
Kong, D.-C., Avdeev, M., Song, L.-N., Zheng, L.-J., Wang, X.-X., & Xu, J.-J. (2024). Water-mediated super-correlated proton-assisted transport mode for solid-state K−O2 batteries. Energy Storage Materials, 72, 103699. doi:10.1016/j.ensm.2024.103699
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