Issue 5, 2020

Selective metathesis synthesis of MgCr2S4 by control of thermodynamic driving forces

Abstract

MgCr2S4 thiospinel is predicted to be a compelling Mg-cathode material, but its preparation via traditional solid-state synthesis methods has proven challenging. Wustrow et al. [Inorg. Chem., 2018, 57, 14] found that the formation of MgCr2S4 from MgS + Cr2S3 binaries requires weeks of annealing at 800 °C with numerous intermediate regrinds. The slow reaction kinetics of MgS + Cr2S3 → MgCr2S4 can be attributed to a miniscule thermodynamic driving force of ΔH = −2 kJ mol−1. Here, we demonstrate that the double ion-exchange metathesis reaction, MgCl2 + 2NaCrS2 → MgCr2S4 + 2NaCl, has a reaction enthalpy of ΔH = −47 kJ mol−1, which is thermodynamically driven by the large exothermicity of NaCl formation. Using this metathesis reaction, we successfully synthesized MgCr2S4 nanoparticles (<200 nm) from MgCl2 and NaCrS2 precursors in a KCl flux at 500 °C in only 30 minutes. NaCl and other metathesis byproducts are then easily washed away by water. We rationalize the selectivity of MgCr2S4 in the metathesis reaction from the topology of the DFT-calculated pseudo-ternary MgCl2–CrCl3–Na2S phase diagram. Our work helps to establish metathesis reactions as a powerful alternative synthesis route to inorganic materials that have otherwise small reaction energies from conventional precursors.

Graphical abstract: Selective metathesis synthesis of MgCr2S4 by control of thermodynamic driving forces

Supplementary files

Article information

Article type
Communication
Submitted
11 דצמ 2019
Accepted
24 פבר 2020
First published
24 פבר 2020

Mater. Horiz., 2020,7, 1310-1316

Author version available

Selective metathesis synthesis of MgCr2S4 by control of thermodynamic driving forces

A. Miura, H. Ito, C. J. Bartel, W. Sun, N. C. Rosero-Navarro, K. Tadanaga, H. Nakata, K. Maeda and G. Ceder, Mater. Horiz., 2020, 7, 1310 DOI: 10.1039/C9MH01999E

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.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements