Structural properties of the thermoelectric material CuCrS2 and of deintercalated CuxCrS2 on different length scales: X-ray diffraction, pair distribution function and transmission electron microscopy studies

Anna-Lena Hansen; Torben Dankwort; Hendrik Groß; Martin Etter; Jan König; Viola Duppel; Lorenz Kienle; Wolfgang Bensch

doi:10.1039/C7TC02983G

Structural properties of the thermoelectric material CuCrS₂ and of deintercalated Cu_xCrS₂ on different length scales: X-ray diffraction, pair distribution function and transmission electron microscopy studies†

Anna-Lena Hansen,^a Torben Dankwort,^b Hendrik Groß,^b Martin Etter,^c Jan König,^d Viola Duppel,^e Lorenz Kienle^b and Wolfgang Bensch

*^a

Author affiliations

* Corresponding authors

^a Institute of Inorganic Chemistry, Kiel University, Max-Eyth-Str. 2, D-24118 Kiel, Germany
E-mail: WBENSCH@AC.UNI-KIEL.DE

^b Intitute for Materials Science, Kiel University, Kaiserstrasse 2, 24143 Kiel, Germany

^c Deutsches Elektronen-Synchrotron (DESY), Hamburg 22607, Germany

^d Fraunhofer Institute for Physical Measurement Techniques IPM, Heidenhofstrasse 8, 79110 Freiburg, Germany

^e Nanochemistry, Max Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart, Germany

Abstract

We report on the structural alterations of the thermoelectric material CuCrS₂ introduced by the removal of 1/3 of the Cu⁺ ions which are located between CrS₂ layers. X-ray diffraction (XRD) and pair distribution function (PDF) analyses revealed a newly formed Cu_0.66CrS₂ phase with monoclinic symmetry and a 3a superstructure. Simultaneously, a distortion of CrS₆ octahedra is observed strongly indicating the oxidation of Cr³⁺ → Cr⁴⁺ leading to a Jahn–Teller distortion. The structural features extracted from XRD indicate a pronounced disorder in the cationic sub-lattice at moderate temperatures (400 K). Transmission electron microscopy (TEM) examination elucidates the formation of a second Cu_0.66CrS₂ phase without the superstructure, caused by incipient Cu⁺ mobility upon beam irradiation. The synergetic combination of high temperature XRD and TEM investigations unveiled the complete mechanism of the phase transition occurring at 503 K, where a transformation into the spinel CuCr₂S₄ and stoichiometric CuCrS₂ occurs.

$Graphical abstract: Structural properties of the thermoelectric material CuCrS2 and of deintercalated CuxCrS2 on different length scales: X-ray diffraction, pair distribution function and transmission electron microscopy studies$

Supplementary files

Article information

DOI: https://doi.org/10.1039/C7TC02983G
Article type: Paper
Submitted: 04 Jul 2017
Accepted: 23 Aug 2017
First published: 24 Aug 2017

Download Citation

J. Mater. Chem. C, 2017,5, 9331-9338

Permissions

Request permissions

Structural properties of the thermoelectric material CuCrS₂ and of deintercalated Cu_xCrS₂ on different length scales: X-ray diffraction, pair distribution function and transmission electron microscopy studies

A. Hansen, T. Dankwort, H. Groß, M. Etter, J. König, V. Duppel, L. Kienle and W. Bensch, J. Mater. Chem. C, 2017, 5, 9331 DOI: 10.1039/C7TC02983G

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Journal of Materials Chemistry C