Operando spectroscopy—measurement during actual operation—has emerged as a critical technique for understanding electrochemical systems, but cost and complexity have limited its use. A new tutorial in the research literature addresses this gap by demonstrating how infrared (IR) spectroscopy, a technique available in most laboratories, can deliver real-time molecular insight into battery and electrolysis reactions.
Unlike synchrotron-based methods requiring specialized facilities, operando IR directly monitors bond-specific changes as reactions occur in electrochemical cells. The approach is particularly valuable for energy professionals developing lithium-ion batteries, hydrogen electrolyzers, fuel cells, and electrocatalysts, as it reveals reaction pathways and degradation mechanisms that conventional post-mortem analysis cannot capture.
The challenge lies in experimental design and data interpretation. Custom-built spectroelectrochemical cells must replicate standard electrochemical performance while accommodating optical access. Researchers must then extract meaningful IR spectra from complex datasets using subtraction methods or multivariate analysis, often supported by computational modeling to assign molecular features and predict spectra of reactive intermediates.
Recent advances are making operando IR more accessible. Synchrotron-based IR (SR-IR) offers enhanced spatial resolution, while surface-enhanced IR absorption spectroscopy (SEIRAS) amplifies weak signals from interfacial reactions. Optic fiber coupling and emerging non-linear spectroscopic combinations promise future breakthroughs in studying solid-electrolyte interfaces and electrochemical dynamics.
For grid-scale energy storage and renewable integration, operando IR accelerates development of stable battery chemistries and efficient water electrolyzers. By lowering barriers to adoption through standardized protocols and improved data handling, this technique could significantly advance materials science for the power and energy sector.
