Changes of Anion Exchange Membrane Properties During Chemical Degradation

Abstract

Water content plays a major role in the properties of anion-exchange membranes (AEMs) and, therefore, in the AEM fuel cell (AEMFC) performance and performance stability. Characterization of AEMs during membrane degradation is critical in order to understand the membrane behavior during fuel cell operation time. In spite of its importance, the relationship between different membrane properties during chemical degradation has yet to be investigated. In this study, we measure the changes in AEM propertiesin particular, ion exchange capacity (IEC), water uptake (WU) and conductivityduring membrane chemical degradation in alkaline medium. To the best of our knowledge, this is the first time this kind of data has been investigated. While all the properties change during AEM degradation, results indicate that membrane WU decreases linearly with decreasing IEC; however, AEM ion-conductivity shows a sigmoidal-like shape relationship with IEC. We introduce a simple model to explain these effects.

Electrospun Anion-Conducting Ionomer Fibers—Effect of Humidity on Final Properties

“…The WU of the electrospun ionomer samples was measured using a VTI SA + instrument (TA Instruments, New Castle, DE, USA), using protocols detailed elsewhere [55][56][57][58]. In brief, each electrospun ionomer sample was dried in situ for a maximum of 60 min at 50 • C and RH close to 0%.…”

Synthesis of CeOx‐Decorated Pd/C Catalysts by Controlled Surface Reactions for Hydrogen Oxidation in Anion Exchange Membrane Fuel Cells

“…Significant progress has been achieved recently in the field of anion exchange membrane fuel cells (AEMFCs). [1][2][3] In spite of the remarkable development of this technology, the deployment of AEMFCs is still hindered by the chemical degradation of the anion exchange membrane (AEM) and ionomers, [4][5][6][7][8][9][10][11] carbonation issues, [12][13][14][15] and by the sluggish kinetics of the hydrogen oxidation reaction (HOR). [2,16,17] It has been shown that the HOR kinetics in alkaline media is two to three orders of magnitude lower than that in acidic media, [18,19] even for the most active catalysts such as Pt, [17,[19][20][21][22] Rh, [23] and Ir.…”

The alkali degradation of LDPE-based radiation-grafted anion-exchange membranes studied using different ex situ methods

“…As well as AEM water content and water diffusivity being critical for high OH À conductivities and high AEMFC performances, [47][48][49][50][51][52][53] hydration is also key to enhancing the alkali stabilities of AEMs. 45,[54][55][56][57][58][59][60] Note, a very recent result shows that LDPE-TMA-based RG-AEMs can be successfully employed in AEMFCs at 125 C for reasonable periods of time when suitably hydrated. 61 L-AEM-TMA and L-AEM-MPY were also tested at 60 C in a RH ¼ 10% TGA test (Fig.…”