Fluorine-Free Gas Diffusion Media for Polymer Electrolyte Fuel Cells Part I: Silicone-based Microporous Layers
- 1Chemical Engineering and Chemistry , Eindhoven University of Technology, Het Kranenveld 14, Eindhoven, North Brabant , Netherlands, 5600MB
Abstract
The widespread use of fluoropolymers in electrochemical energy systems, coupled with increasing environmental, health, and regulatory concerns surrounding per- and polyfluoroalkyl substances (PFAS), is motivating the development of fluorine-free alternatives. Here, silicone-based resins are evaluated as fluorine-free binders for microporous layers (MPLs) and integrated into fully fluorine-free gas diffusion media (GDMs). Using Sylgard 184 silicone elastomer, the binder content was systematically varied, identifying 25 wt.% as the lowest loading that provided sufficient water repellency. At this loading, the influence of binder chemistry was investigated by replacing Sylgard 184 with KR-220L, a methyl silicone rigid resin. Although the resin chemistry strongly affected MPL thickness, porosity, and crack formation, its impact on fuel-cell performance was limited. Fully fluorinefree GDMs were then fabricated by depositing silicone-based MPLs onto carbon fiber substrates hydrophobized via organosilicon electrografting. Replacing a commercial PTFEtreated substrate with the fluorine-free electrografted substrate resulted in only a minor decrease in current density, from 4.2 to 4.0 A cm-2 at 0.3 V under high-humidity conditions; both exceeded the commercial fluorinated reference (3.8 A cm-2). Accelerated stress testing further demonstrated promising durability. Overall, silicone-based materials represent a viable route toward replacing fluorinated components in GDMs.
Related
- A Nano-Bismuth–Silicone Polymer Composite as Shielding for X-Rays in Extreme-Environment Applications: Experimental and Simulation Studies
- Reducing Synthetic Complexity: A Fluorine-Free Benzodithiophene-Thienopyrrolodione Donor Polymer by Direct Arylation Polycondensation for Organic Photovoltaics
- PolyGPT: A Decoder-Only Transformer for Polymer Electrolyte Design
- Not comparing like with like: a measurement-conditions audit of the solid polymer electrolyte literature
- A High-Performance Sustainable Solid-State Supercapacitor Utilizing Hazelnut Shell-Derived Activated Carbon and Optimized Polymer Blend Electrolyte
BibTeX
@misc{sinisgalli2026fluorinefree,
title = {{Fluorine-Free Gas Diffusion Media for Polymer Electrolyte Fuel Cells Part I: Silicone-based Microporous Layers}},
author = {Irene Sinisgalli and Nicolaas J. M. van Leth and Antoni Forner-Cuenca},
howpublished = {ChemRxiv},
year = {2026},
month = aug,
doi = {10.26434/chemrxiv.15008053/v1},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008053/v1},
note = {CC BY-NC-ND},
}
RIS
TY - UNPB
TI - Fluorine-Free Gas Diffusion Media for Polymer Electrolyte Fuel Cells Part I: Silicone-based Microporous Layers
AU - Irene Sinisgalli
AU - Nicolaas J. M. van Leth
AU - Antoni Forner-Cuenca
PY - 2026
DA - 2026/08/30
PB - ChemRxiv
DO - 10.26434/chemrxiv.15008053/v1
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008053/v1
AB - The widespread use of fluoropolymers in electrochemical energy systems, coupled with increasing environmental, health, and regulatory concerns surrounding per- and polyfluoroalkyl substances (PFAS), is motivating the development of fluorine-free alternatives. Here, silicone-based resins are evaluated as fluorine-free binders for microporous layers (MPLs) and integrated into fully fluorine-free gas diffusion media (GDMs). Using Sylgard 184 silicone elastomer, the binder content was systematically varied, identifying 25 wt.% as the lowest loading that provided sufficient water repellency. At this loading, the influence of binder chemistry was investigated by replacing Sylgard 184 with KR-220L, a methyl silicone rigid resin. Although the resin chemistry strongly affected MPL thickness, porosity, and crack formation, its impact on fuel-cell performance was limited. Fully fluorinefree GDMs were then fabricated by depositing silicone-based MPLs onto carbon fiber substrates hydrophobized via organosilicon electrografting. Replacing a commercial PTFEtreated substrate with the fluorine-free electrografted substrate resulted in only a minor decrease in current density, from 4.2 to 4.0 A cm-2 at 0.3 V under high-humidity conditions; both exceeded the commercial fluorinated reference (3.8 A cm-2). Accelerated stress testing further demonstrated promising durability. Overall, silicone-based materials represent a viable route toward replacing fluorinated components in GDMs.
ER -