Ionic conduction in ammonia functionalised closo-dodecaborates MB12H11NH3 (M = Li and Na)

Metal hydroborates and their derivatives have been receiving attention as potential solid-state ion conductors for battery applications owing to their impressive electrochemical and mechanical characteristics. However, to date only a fraction of these compounds has been investigated as solid-state e...

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Bibliographic Details
Main Authors: Jensen,Steffen R.H., Jørgensen, M., Nguyen, Thi Phuong Thao, Nolan, Greg, Buckley, Craig E., Jensen, T.R., Paskevicius, Mark
Format: Journal Article
Language:English
Published: 2024
Online Access:http://purl.org/au-research/grants/arc/DP230100429
http://hdl.handle.net/20.500.11937/97001
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Summary:Metal hydroborates and their derivatives have been receiving attention as potential solid-state ion conductors for battery applications owing to their impressive electrochemical and mechanical characteristics. However, to date only a fraction of these compounds has been investigated as solid-state electrolytes. Here, MB12H11NH3 (M = Li and Na) hydroborates are synthesized and investigated as electrolyte materials for all-solid-state batteries. The room temperature α-NaB12H11NH3 was structurally solved in P212121 (a = 7.1972(3) Å, b = 9.9225(4) Å, and c = 14.5556(5) Å). It shows a polymorphic structural transition near 140 °C to cubic Fm3̄m. LiB12H11NH3 and NaB12H11NH3 exhibit cationic conductivities of σ(Li+) = 3.0 × 10−4 S cm−1 and σ(Na+) = 1.2 × 10−4 S cm−1 at 200 °C. Hydration is found to improve ionic conductivity of the hydroborates. It is presumed that modest ionic conductivities could be due to a lack of significant re-orientational dynamics in the crystal structure resulting from the presence of the bulky -NH3 group in the anion.