Quantifying Chemical Capacitance and Diffusion Coefficients in Hydrogenated La<sub>0.6</sub>Sr<sub>0.4</sub>FeO<sub>3-<i>δ</i></sub> <i>via</i> <i>Operando</i> Spectro-Electrochemical Characterizations.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 41582535.
- Also identified by DOI 10.1021/acs.nanolett.5c06258.
- No licence information is recorded for this record.
- Because redistribution is not established, this page shows the abstract only. Follow the links below for the full text.
Abstract
Hydrogenation in redox-active oxides is widely used to modulate electronic structure and, in turn, optical, magnetic, and transport properties in electrochromic, energy-storage, and ionotronic devices. Quantitatively resolving hydrogenation is therefore critical for rational device design. However, a general <i>operando</i> framework that directly quantifies potential-dependent proton concentration while decoupling ionic and electronic transport and linking both to defect thermodynamics remains limited. Herein, using La<sub>0.6</sub>Sr<sub>0.4</sub>FeO<sub>3-<i>δ</i></sub> thin films as a model system, we develop an integrated methodology that combines <i>operando</i> spectro-electrochemistry, electrochemical impedance spectroscopy, and defect-chemistry analysis to interrogate hydrogenation across applied potentials. The <i>operando</i> spectro-electrochemical signal, calibrated by coulometric titration, maps absorbance changes to proton concentration, enabling direct determination of its potential dependence. Impedance spectroscopy separates ionic and electronic contributions, yielding potential-dependent chemical capacitance and ionic conductivity. Defect-chemistry analysis further supports the reliability of the observed potential-dependent trends. We believe this approach is readily transferable to other redox-active oxides.