Observation of water droplets in microporous layers for polymer electrolyte fuel cells by X‐ray computed nano‐tomography

• Published in: Journal of synchrotron radiation Vol. 29; no. 5; pp. 1258 - 1264
• Main Authors: Yamaguchi, Satoshi, Kato, Satoru, Yoshimune, Wataru, Setoyama, Daigo, Kato, Akihiko, Nagai, Yasutaka, Suzuki, Takahisa, Takeuchi, Akihisa, Uesugi, Kentaro
• Format: Journal Article
• Language: English
• Published: 5 Abbey Square, Chester, Cheshire CH1 2HU, England International Union of Crystallography 01-09-2022; John Wiley & Sons, Inc
• Subjects: Apodization; Computed tomography; Droplets; Electrolytic cells; Fresnel zones; gas diffusion layer; hydrophobic material; Medical imaging; microporous layer; Phase plates; polymer electrolyte fuel cell; Polymers; Proton exchange membrane fuel cells; Research Papers; Water; water droplet; Water drops; X‐ray computed nano‐tomography; Zone plates
• ISSN: 1600-5775; 0909-0495; 1600-5775
• DOI: 10.1107/S1600577522007949

An X‐ray computed nano‐tomography (nano‐CT) system has been established at the BL33XU beamline of SPring‐8. The optical system consists of pseudo‐Köhler illumination with a sector condenser zone plate, an apodization Fresnel zone plate as the objective lens, and a Zernike phase plate. The imaging detector is a fiber‐coupling type X‐ray camera. The performance of the X‐ray nano‐CT system was confirmed by imaging an X‐ray test chart. The system was subsequently applied to the observation of a microporous layer for polymer electrolyte fuel cells and a simulated microporous layer including liquid water. The nano‐CT system, which can perform a computed tomography measurement in less than 4 min, allowed visualization of a spherical water droplet produced in the microporous layer. In the present study, the shape of water droplets in a nanoscale porous structure is investigated.
Condensed liquid water was observed in the pores of a model microporous layer for a polymer electrolyte fuel cell using an X‐ray computed nano‐tomography system constructed at the BL33XU beamline of SPring‐8. The water droplets had a spherical shape, regardless of the structure of the pores in the hydrophobic porous material.