(369e) Assessing and Improving Electrode Structures for Scalable CO2 Reduction Using in Operando electrochemical Techniques

Electrochemical CO₂ reduction is a promising technology to capture and convert CO₂ to valuable chemicals. High Faradaic efficiencies of CO₂ reduction products can be achieved with zero-gap alkaline CO₂ electrolyzers with a supporting electrolyte at the anode (anolyte) at current densities above 250 mA/cm² [1]. While much of the field has focused on tailoring the electrocatalyst structure and electrochemical interfaces to minimize kinetic overpotentials, there is a broader need to understand how different cell configurations can impact the observable electrode properties and performance. For example, we have found the presence of KOH at a copper-coated gas diffusion electrode significantly enhances its capacitance (proxy for electrochemically active surface area) and ionic conductivity by 4 and 447 times, respectively [2]. Additionally, the low coverage of Nafion in these electrodes suggests the ionomer has a very limited role in tuning the electrochemical interface in these electrodes [2].

This presentation will describe our methodology to study CO2 electrodes in operando independent of the material selection and cell configuration. We use electrochemical impedance spectroscopy to monitor changes in electrode properties at different relative humidities and in different cell configurations to elucidate key performance-limiting phenomena.

References

[1] Y. Chen, et al. ACS Energy Letters 2020 5 (6), 1825-1833.

[2] P. Saha et al 2023 J. Electrochem. Soc. 170 014505