Methodologies for Operando ATR-IR Spectroscopy of Magnesium Battery Electrolytes

Rudra N Samajdar; Scott A Brown; Shravan K Kairy; Stuart D Robertson; Andrew J Wain

doi:10.1021/acs.analchem.2c02843

Methodologies for Operando ATR-IR Spectroscopy of Magnesium Battery Electrolytes

Anal Chem. 2022 Nov 1;94(43):14985-14993. doi: 10.1021/acs.analchem.2c02843. Epub 2022 Oct 19.

Authors

Rudra N Samajdar^{1

2}, Scott A Brown^{1

2}, Shravan K Kairy¹, Stuart D Robertson², Andrew J Wain¹

Affiliations

¹ Department of Electromagnetic and Electrochemical Technologies, National Physical Laboratory, Teddington TW11 0LW, U.K.
² WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow G1 1XL, U.K.

PMID: 36260706
DOI: 10.1021/acs.analchem.2c02843

Abstract

We explore the suitability of operando attenuated total reflection infrared (ATR-IR) spectroscopy methodologies for the study of organoaluminate electrolytes for Mg battery applications. The "all-phenyl complex" in tetrahydrofuran (THF), with the molecular structure [Mg₂Cl₃·6THF]⁺[AlPh₄]^-, is used as an exemplar electrolyte to compare two different spectroelectrochemical cell configurations. In one case, a Pt gauze is used as a working electrode, while in the second case, a thin (∼10 nm) Pt film working electrode is deposited directly on the surface of the ATR crystal. Spectroscopic measurements indicate substantial differences in the ATR-IR response for the two configurations, reflecting the different spatial arrangements of the working electrode with respect to the ATR sampling volume. The relative merits and potential pitfalls associated with the two approaches are discussed.