ChemRxiv
These are preliminary reports that have not been peer-reviewed. They should not be regarded as conclusive, guide clinical practice/health-related behavior, or be reported in news media as established information. For more information, please see our FAQs.
1/1
0/0

Highly proton conductive membranes based on carboxylated cellulose nanofibres and their performance in proton exchange membrane fuel cells

preprint
revised on 16.08.2019 and posted on 16.08.2019 by Valentina Guccini, Annika Carlson, Shun Yu, Göran Lindbergh, Rakel Wreland Lindström, Germán Salazar-Alvarez

The performance of thin carboxylated cellulose nanofiber-based (CNF) membranes as proton exchange membranes in fuel cells has been measured in-situ as a function of CNF surface charge density (600 and 1550 µmol g-1), counterion (H+or Na+), membrane thickness and fuel cell relative humidity (RH 55 to 95 %). The structural evolution of the membranes as a function of RH, as measured by Small Angle X-ray scattering, shows that water channels are formed only above 75 % RH. The amount of absorbed water was shown to depend on the membrane surface charge and counter ions (Na+or H+). The high affinity of CNF for water and the high aspect ratio of the nanofibers, together with a well-defined and homogenous membrane structure, ensures a proton conductivity exceeding 1 mS cm-1at 30 °C between 65 and 95 % RH. This is two orders of magnitude larger than previously reported values for cellulose materials and only one order of magnitude lower than Nafion 212. Moreover, the CNF membranes are characterized by a lower hydrogen crossover than Nafion, despite being ≈ 30 % thinner. Thanks to their environmental compatibility and promising fuel cell performance the CNF membranes should be considered for new generation proton exchange membrane fuel cells.

History

Email Address of Submitting Author

gersal@protonmail.com

Institution

Stockholm University

Country

Sweden

ORCID For Submitting Author

0000-0002-0671-435X

Declaration of Conflict of Interest

The authors declare no conflict of interests.

Version Notes

Title fixed

Exports