Fast lithium ion conducting garnet-type metal oxides are promising electrolytes for next-generation all-solid-state Li batteries and beyond Li-ion intercalation batteries, including Li-air and Li-S.¹ Li-stuffed garnets show high total Li-ion conductivity (> 10^-4 S/cm at room temperature) and good chemical stability against reaction with elemental Li.^2,3 In the presence of moisture and aqueous environments, lithium-stuffed garnets are known to undergo fast H⁺/Li⁺ exchange, ³ while they are known to react with carbon dioxide, forming Li₂CO₃, under ambient atmosphere.⁴ Li-stuffed garnets exhibit wide electrochemical stability window of 9 V vs. Li⁺/Li at room temperature.⁴ Li dendrite formation and high area specific resistance for the reaction are being addressed by surface modification.^5,6 In this talk, an overview of the chemical and electrochemical stability of various lithium-based garnets, developed in authors’ group and also elsewhere, against moisture/humidity, carbon dioxide, sulfur, and metallic lithium will be discussed.⁴

References

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6. K. K. Fu, Y. H. Gong, B. Y. Liu, Y. Z. Zhu, S. M. Xu, Y. G. Yao, W. Luo, C. W. Wang, S. D. Lacey, J. Q. Dai, Y. N. Chen, Y. F. Mo, E. Wachsman and L. B. Hu, Sci, Adv., 3, 11 (2017).