Open AccessStudy of the Temperature- and Pressure-Dependent Structural Properties of Alkali Hydrido-closo-borate Compounds
Author(s) -
Romain Moury,
Zbigniew Łodziana,
Arndt Remhof,
Léo Duchêne,
Elsa Roedern,
Angelina Gigante,
HansRudolf Hagemann
Publication year - 2022
Publication title -
inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 233
eISSN - 1520-510X
pISSN - 0020-1669
DOI - 10.1021/acs.inorgchem.1c03681
Subject(s) - chemistry , alkali metal , thermal expansion , boron , phase transition , diffraction , density functional theory , phase (matter) , icosahedral symmetry , thermodynamics , crystallography , computational chemistry , organic chemistry , physics , optics
In this work, we report on the structural properties of alkali hydrido- closo -(car)borates, a promising class of solid-state electrolyte materials, using high-pressure and temperature-dependent X-ray diffraction experiments combined with density functional theory (DFT) calculations. The mechanical properties are determined via pressure-dependent diffraction studies and DFT calculations; the shear moduli appear to be very low for all studied compounds, revealing their high malleability (that can be beneficial for the manufacturing and stable cycling of all-solid-state batteries). The thermodiffraction experiments also reveal a high coefficient of thermal expansion for these materials. We discover a pressure-induced phase transition for K 2 B 12 H 12 from Fm 3̅ to Pnnm symmetry around 2 GPa. A temperature-induced phase transition for Li 2 B 10 H 10 was also observed for the first time by thermodiffraction, and the crystal structure determined by combining experimental data and DFT calculations. Interestingly, all phases of the studied compounds (including newly discovered high-pressure and high-temperature phases) may be related via a group-subgroup relationship, with the notable exception of the room-temperature phase of Li 2 B 10 H 10 .