Filling the Gaps in the LiBr-LiOH Phase Diagram: A Study on the High-Temperature Li 3 (OH) 2 Br Phase

Journal article

In this paper, we build on previous work to characterize a phase with stoichiometry Li3(OH)2Br existing between ∼225 and ∼275 °C in the LiBr-LiOH phase diagram. Diffraction studies indicate that the phase takes a hexagonal unit cell, and theoretical modeling is used to suggest a possible crystal structure. Nuclear magnetic resonance spectroscopy and electrochemical impedance spectroscopy measurements demonstrate excellent lithium-ion dynamics in this phase, with an ionic conductivity of 0.12 S cm–1 at 250 °C. Initial attempts to stabilize this phase at room temperature through quenching were not successful. Instead, a metastable state demonstrating poor ionic conductivity is found to form. This is an important consideration for the synthesis of Li2OHBr solid-state electrolytes (also found in the LiBr-LiOH phase diagram) which are synthesized by cooling through phase fields containing Li3(OH)2Br, and are hence susceptible to these impurities.

Authors: Milan, E; Quirk, JA; Hashi, K; Cattermull, J; Goodwin, AL

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: American Chemical Society
• Journal: Chemistry of Materials
• Volume: 37
• Issue: 8
• Pages: 2899-2906
• Publication date: 2025-04-04
• Acceptance date: 2025-03-26
• DOI: 10.1021/acs.chemmater.5c00206
• EISSN: 1520-5002
• ISSN: 0897-4756
• Language: English