Open AccessCharacterization of Electrochemical Processes in Metal–Organic Batteries by X-ray Raman Spectroscopy
Author(s) -
Ava Rajh,
Iztok Arčon,
K. Bučar,
M. Z̆itnik,
M. Petrič,
Alenka Vesel,
Jan Bitenc,
Urban Košir,
Robert Dominko,
H. Gretarsson,
Martin Sundermann,
M. Kavčič
Publication year - 2022
Publication title -
journal of physical chemistry. c./journal of physical chemistry. c
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.401
H-Index - 289
eISSN - 1932-7455
pISSN - 1932-7447
DOI - 10.1021/acs.jpcc.1c10622
Subject(s) - raman spectroscopy , absorption spectroscopy , electrochemistry , analytical chemistry (journal) , chemistry , absorption (acoustics) , cathode , spectroscopy , battery (electricity) , density functional theory , materials science , electrode , computational chemistry , optics , organic chemistry , power (physics) , physics , quantum mechanics , composite material
X-ray Raman spectroscopy (XRS) is an emerging spectroscopic technique that utilizes inelastic scattering of hard X-rays to study X-ray absorption edges of low Z elements in bulk material. It was used to identify and quantify the amount of carbonyl bonds in a cathode sample, in order to track the redox reaction inside metal-organic batteries during the charge/discharge cycle. XRS was used to record the oxygen K-edge absorption spectra of organic polymer cathodes from different multivalent metal-organic batteries. The amount of carbonyl bond in each sample was determined by modeling the oxygen K-edge XRS spectra with the linear combination of two reference compounds that mimicked the fully charged and the fully discharged phases of the battery. To interpret experimental XRS spectra, theoretical calculations of oxygen K-edge absorption spectra based on density functional theory were performed. Overall, a good agreement between the amount of carbonyl bond present during different stages of battery cycle, calculated from linear combination of standards, and the amount obtained from electrochemical characterization based on measured capacity was achieved. The electrochemical mechanism in all studied batteries was confirmed to be a reduction of double carbonyl bond and the intermediate anion was identified with the help of theoretical calculations. X-ray Raman spectroscopy of the oxygen K-edge was shown to be a viable characterization technique for accurate tracking of the redox reaction inside metal-organic batteries.