Document Type
Article
Abstract
CsH2PO4 (CDP) is a well-known super-protonic conductor. However, it must operate under high humidity conditions to prevent dehydration and fast conductivity decay. Herein, we report that adding hydrophilic SnO2 into CDP can suppress the rate of dehydration of CDP, thus stabilizing protonic conductivity over a broader range of water partial pressures (pH2O). A total of seven compositions of (1 - x)CDP/(x)SnO2 were prepared, where 5 ≤ x ≤ 40 (wt%), and examined for their phasal, microstructural, and vibrational properties using X-ray diffraction, field emission scanning electron microscopy, and Raman spectroscopy. The signature of H2O retained in SnO2-added CPD was confirmed by Fourier transform infrared (FTIR) spectroscopy. Among these samples, 18 wt% SnO2 in CDP stood out, showing a stable protonic conductivity of 0.6 x 10-2 S cm-1 at 250 °C, even at 10% H2O. We also provide data from pre- and post-test characterization to facilitate the understanding of the observed stability improvement and degradation mechanisms. Finally, we show stable H2 pumping performance of electrochemical cells with pure CDP and 18 wt% SnO2–CDP electrolyte and Pt/C electrode. Overall, 18 wt% SnO2–CDP is the best composition, showing stable conductivity under reduced H2O conditions and 18 wt% SnO2–CDP electrolyte with Pt/C electrode is the best membrane electrode assembly (MEA) for electrochemical H2 pumping for lower water partial pressure applications.
Digital Object Identifier (DOI)
Publication Info
Published in Energy Advances, Volume 4, 2025, pages 424-434.
Rights
© 2025 The Author(s). Published by the Royal Society of Chemistry This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.