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DOE OSTI · 2575288

LiPF 6 under pressure: a symmetry-mode-based structural analysis

Ridley, Chris J. [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)] (ORCID:0000000230609656)·Bull, Craig L. [Science and Technology Facilities Council (STFC), Oxford (United Kingdom). Rutherford Appleton Lab., ISIS Neutron Source; Univ. of Edinburgh, Scotland (United Kingdom)]·Funnell, Nicholas P. [Science and Technology Facilities Council (STFC), Oxford (United Kingdom). Rutherford Appleton Lab., ISIS Neutron Source]
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Abstract

The lithium salt LiPF 6 is a key component in commercial lithium-ion battery (LIB) electrolytes. However, its structural properties under pressure remain unexplored, despite increasing interest in the effect of pressure on electrolyte behaviour, and a growing interest in high pressure synthesis of new Li-hexafluoride cathode materials. Here, we present the first high pressure neutron diffraction study of solid LiPF 6 up to 7.4 GPa. Refinements reveal that the ambient rhombohedral structure (space group R$\overline{3}$) remains stable throughout, with pressure accommodated primarily by tilting of the corner-shared LiF 6 and PF 6 octahedra and contraction of the LiF 6 units. In conclusion, this study establishes a foundation for understanding the phase behaviour of Li-based hexafluorides under extreme conditions.

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25 ENERGY STORAGELiPF6lithium-ion electrolytesneutron diffractionsymmetry-mode analysis

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Ridley, Chris J. [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)] (ORCID:0000000230609656), Bull, Craig L. [Science and Technology Facilities Council (STFC), Oxford (United Kingdom). Rutherford Appleton Lab., ISIS Neutron Source; Univ. of Edinburgh, Scotland (United Kingdom)], Funnell, Nicholas P. [Science and Technology Facilities Council (STFC), Oxford (United Kingdom). Rutherford Appleton Lab., ISIS Neutron Source]. 2025-07-05. LiPF 6 under pressure: a symmetry-mode-based structural analysis. https://doi.org/10.1080/08957959.2025.2524384

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