Issue 10, 2012

3 In situ and operando determination of the water content distribution in proton conducting membranes for fuel cells: a critical review

Abstract

Proton exchange membrane fuel cells have been recognized as a promising zero-emission power source for portable, mobile and stationary applications. The information of water content distribution in the different components of the cell during operation, particularly the proton conducting membrane, is a critical issue for the validation of mass transfer models, the definition of optimized operating conditions and the development of efficient systems with innovative designs for efficient water management. In order to fully understand the way a fuel cell performs, water transport and distribution have to be investigated in situ and operando. In this review, we critically examine the state-of-the-art of operando diagnostics sensitive to the membrane water content, particularly those techniques able (in principle) to give insights into water transport occurring along both the in- and through-plane directions. Particular attention is devoted to experimental results obtained across the membrane thickness i.e. to the determination of water concentration profiles originating from the water activity and electrical gradients occurring through the working fuel cell. Different operando techniques have been developed for this purpose, from the early 1990s up to the last few years: internal resistance measurements, magnetic resonance and neutron imaging, neutron and X-ray scattering, confocal μ-Raman spectroscopy. These techniques can be roughly separated as either direct (i.e. the water amount can be directly derived from the detected signal, avoiding sometimes arbitrary assumptions during data processing) but intrusive (i.e. they require significant modification of the fuel cell, compared to the current design and materials) or indirect but with a significantly lower intrusiveness. It appears that operando measurements of the membrane water distribution allow a unique picture of how the internal part of the fuel cell works, thus certainly contributing to the development of more effective cell designs and materials in the near future. Nevertheless, improvement in the fundamental understanding of the actual fuel cell requires further efforts to increase spatial and, more particularly, temporal resolution of current operando techniques. Also, the comparison of limitations arising from the basic principles of the different operando approaches suggests that ultimate progress will arise from the combination of complementary techniques for simultaneous measurements.

Graphical abstract: 3 In situ and operando determination of the water content distribution in proton conducting membranes for fuel cells: a critical review

Article information

Article type
Review Article
Submitted
02 Apr 2012
Accepted
30 Jul 2012
First published
31 Jul 2012

Energy Environ. Sci., 2012,5, 8824-8847

3 In situ and operando determination of the water content distribution in proton conducting membranes for fuel cells: a critical review

S. Deabate, G. Gebel, P. Huguet, A. Morin and G. Pourcelly, Energy Environ. Sci., 2012, 5, 8824 DOI: 10.1039/C2EE21834H

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements