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Mechanochemical Synthesis: A Tool to Tune Cation Site Disorder and Ionic Transport Properties of Li 3 MCl 6 (M = Y, Er) Superionic Conductors
Author(s) -
Schlem Roman,
Muy Sokseiha,
Prinz Nils,
Banik Ananya,
ShaoHorn Yang,
Zobel Mirijam,
Zeier Wolfgang G.
Publication year - 2020
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.201903719
Subject(s) - materials science , ionic conductivity , ionic bonding , crystallization , chemical physics , lithium (medication) , conductivity , density functional theory , fast ion conductor , halide , ion , chemistry , crystallography , thermodynamics , computational chemistry , inorganic chemistry , physics , medicine , organic chemistry , electrode , electrolyte , endocrinology
The lithium‐conducting, rare‐earth halides, Li 3 MX 6 (M = Y, Er; X = Cl, Br), have garnered significantly rising interest recently, as they have been reported to have oxidative stability and high ionic conductivities. However, while a multitude of materials exhibit a superionic conductivity close to 1 mS cm −1 , the exact design strategies to further improve the ionic transport properties have not been established yet. Here, the influence of the employed synthesis method of mechanochemical milling, compared to subsequent crystallization routines as well as classic solid‐state syntheses on the structure and resulting transport behavior of Li 3 ErCl 6 and Li 3 YCl 6 are explored. Using a combination of X‐ray diffraction, pair distribution function analysis, density functional theory, and impedance spectroscopy, insights into the average and local structural features that influence the underlying transport are provided. The existence of a cation defect within the structure in which Er/Y are disordered to a new position strongly benefits the transport properties. A synthetically tuned, increasing degree of this disordering leads to a decreasing activation energy and increasing ionic conductivity. This work sheds light on the possible synthesis strategies and helps to systematically understand and further improve the properties of this class of materials.