Chemical stability of Li4PS4I solid electrolyte against hydrolysis. (March 2021)

• Record Type: Journal Article
• Authors: Calpa, Marcela; Rosero-Navarro, Nataly Carolina; Miura, Akira; Jalem, Randy; Tateyama, Yoshitaka; Tadanaga, Kiyoharu
• Is Part Of: Applied materials today. Volume 22(2021)
• Publication Date: 2021-03
• Subjects: Solid electrolyte -- Sulfide electrolyte -- Chemical stability -- Lithium battery -- All-solid-state battery; Materials science -- Periodicals; Materials -- Research -- Periodicals; 620.1105
• DOI: 10.1016/j.apmt.2020.100918
• Languages: English
• ISSNs: 2352-9407

Abstract

Highlights: Incorporation of LiI in a sulfide solid electrolyte suppressed the H2 S gas generation. Formation of LiIH2 O acting as a barrier between the sulfide electrolyte and H2 O in air. Reversibility of Li4 PS4 I exposed to the ambient atmosphere by simple drying. Abstract: Sulfide solid electrolytes in the Li3 PS4 –LiI system are promising for all-solid-state batteries owing to their high ionic conductivity in the order of 10 −4 S cm −1 and electrochemical stability. Nonetheless, the low chemical stability tendency of sulfide-based materials under ambient atmosphere is a critical issue due to the generation of toxic H2 S gas. In this study, the chemical stability of Li4 PS4 I (Li3 PS4 –LiI) solid electrolyte under ambient atmosphere was investigated and compared with that of Li3 PS4 to analyze the effect of the incorporation of LiI on the chemical stability of sulfide-based electrolytes. No generation of H2 S gas was detected in the Li4 PS4 I solid electrolyte after an exposure of 60 min to the ambient atmosphere with high relative humidity of 40%. The hydrolysis suppression is attributed to the formation of LiI·H2 O, acting as a protective barrier between PS4 3− units in the electrolyte and H2 O molecules in air. The structural reversibility of Li4 PS4 I by simple drying at 180°C was confirmed and the solid electrolyte exhibited an ionic conductivity of 10 −4 S cm −1 at room temperature, similar to that of the sample before the exposure to the ambient atmosphere. Graphical abstract: Image, graphical abstract