Mechanochemical Synthesis: A Tool to Tune Cation Site Disorder and Ionic Transport Properties of Li3MCl6 (M = Y, Er) Superionic Conductors. Issue 6 (17th December 2019)

• Record Type: Journal Article
• Authors: Schlem, Roman; Muy, Sokseiha; Prinz, Nils; Banik, Ananya; Shao‐Horn, Yang; Zobel, Mirijam; Zeier, Wolfgang G.
• Is Part Of: Advanced energy materials. Volume 10:Issue 6(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-12-17
• Subjects: mechanochemical synthesis -- solid electrolyte -- solid‐state battery -- superionic conductor; Energy harvesting -- Materials -- Periodicals; Energy conversion -- Materials -- Periodicals; Energy storage -- Materials -- Periodicals; Photovoltaics -- Periodicals; Fuel cells -- Periodicals; Thermoelectric materials -- Periodicals; 621.31
• DOI: 10.1002/aenm.201903719
• Languages: English
• ISSNs: 1614-6832

Abstract

Abstract: The lithium‐conducting, rare‐earth halides, Li3 MX6 (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 Li3 ErCl6 and Li3 YCl6 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. Abstract : A study on the influence of the synthesis method on the occurring structural disorder demonstrates that the rare‐earth‐cation disorder within the Li3 (Y, Er)Cl6 material system can be engineered to enhance the resulting ionic transport properties. Mechanochemical synthesis, when compared to classic solid‐state syntheses, increases this site disorder, leading to an enhancement of ionic transport properties.