Speaker
Description
Understanding and improving mass and ionic transport mechanisms within the nano-porous membrane used in polymer electrolyte membrane (PEM) water splitting electrolyzers is vital for achieving improved efficiencies that would enable the use of water electrolysis in sustainable energy infrastructures. To achieve this goal, microfluidics electrolyzers can serve as flexible platforms for operando PEM characterization. For example, Krause et al. [1,2] developed a microfluidic PEM electrolyzer with a Nafion membrane capped on top of the channels to probe operando the water content in PEM. The measurements of the PEM water content can then be carried out using imaging methods such as the IR transmittance.
This work aims to improve characterization methods for measuring PEM hydration to get a better understanding of the transport mechanisms in those nano-porous material used in electrochemical applications. An operating microfluidic PEM electrolysis chip is used for operando infrared (IR) spectroscopy [3]. The IR imaging is coupled with electrochemical impedance spectroscopy (EIS) and distribution of relaxation times (DRT) to elucidate the relationship between membrane hydration and ohmic, kinetic, and mass transport losses. IR imaging unveils water diffusion gradients across the PEM of the microfluidic water electrolyzer. Varied H2SO4 anolyte concentrations directly correlated with water diffusion through the PEM, where the highest anolyte concentrations accompanied the strongest water diffusion gradients. We show that tuning the anolyte concentration for visualizing water diffusion across the PEM came with a tradeoff, as the electrochemical performance of the electrolyzer became increasingly unstable. These findings showcase the potential of IR imaging when coupled with a microfluidic PEM electrolyzer and electrochemical characterization techniques, and the influence of anolyte concentration for manipulating the PEM water gradient .
References
[1] K. Krause, M. Garcia, D. Michau, G. Clisson, B. Billinghurst, J. Battaglia, S. Chevalier, Probing membrane hydration in microfluidic polymer electrolyte membrane electrolyzers via operando synchrotron Fourier-transform infrared spectroscopy, Lab Chip. 23 (2023) 4002–4009.
[2] K. Krause, A. Crête-Laurence, D. Michau, G. Clisson, J.-L. Battaglia, S. Chevalier, Water gradient manipulation through the polymer electrolyte membrane of an operating microfluidic water electrolyzer, J Power Sources. 623 (2024) 235297.
[3] S. Chevalier, J.-N. Tourvieille, A. Sommier, C. Pradère, Infrared thermospectroscopic imaging of heat and mass transfers in laminar microfluidic reactive flows, Chemical Engineering Journal Advances. 8 (2021) 100166.
| Country | France |
|---|---|
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