Work

In Situ Small-Angle X-ray Scattering Investigation of Hydrated Membrane Nanostructures in Polymer Electrolyte Fuel Cells

Year: 2026

Type: article

Abstract: High Resolution Image Download MS PowerPoint Slide Understanding the hydration state of polymer electrolyte membranes (PEMs) in operating fuel cells is essential for enhancing performance and ensuring long-term durability. Here, we present an in situ small-angle X-ray scattering (SAXS) approach that enables direct observation of PEM hydration within membrane electrode assemblies. A dedicated in situ SAXS cell was developed to suppress scattering from catalyst layers and isolate membrane-specific signals. In situ measurements revealed that break-in procedures enhanced the structural ordering of the nanophase-separated water domains in the hydrated PEM without altering the water-domain spacing. Systematic measurements further showed that water-domain spacing increased at lower cell temperatures and higher current densities, providing direct structural evidence of hydration dynamics in PEMs. These findings demonstrate that in situ SAXS is a powerful tool for probing membrane nanostructures under realistic fuel cell conditions.

Source: ACS Applied Energy Materials

DOI: 10.1021/acsaem.6c00519

Authors: Wataru Yoshimune, Kazuaki Yaegashi, Satoshi Yamaguchi, Hiroshi Nozaki

Institution: Toyota Central Research and Development Laboratories (Japan)

Language: English

Topic: Fuel Cells and Related Materials

Subfield: Electrical and Electronic Engineering

Field: Engineering

Domain: Physical Sciences

SDG: Affordable and clean energy

Open Access status: hybrid

Estimated APC paid: $4,500