Nanostructured Membrane Electrode Assemblies from Layer-by-Layer Composite/Catalyst Containing Membranes and Their Fuel Cell Performances

Abstract

In this study, two approaches are compared to develop nanostructured membrane electrode assemblies (MEA) using layer-by-layer (lbl) technique. The first is based on the direct deposition of polyallylamine hydrochloride (PAH) and sulfonated polyaniline (sPAni) on Nafion support to prepare lbl composite membrane. In the second approach, sPAni is coated on the support in the presence of platinum (Pt) salt, Nafion solution and Vulcan for obtaining catalyst containing membranes (CCMs). SEM and UV-vis analysis show that the multilayers are deposited on both sides of Nafion successfully. Although H-2/O-2 single cell performances of acid doped lbl composite membrane based MEA are found to be at the range of 126 and 160 mW cm(-2) depending on the number of deposited layers, the cell performance of MEA obtained from catalyst containing lbl self-assembled thin membrane (PAH/sPAni-H+)(10-Pt) is found to be 360 mW cm(-2) with a Pt utilization of 720 mW mgPt(-1). This performance is 82% higher as compared to original Nafion((R))117 based MEA (198 mW cm(-2)). From the cell performance evaluations for different structured MEAs, it is mainly found out that the use of lbl CCMs instead of composite membranes and fabrication of thinner electrolytes result in a higher H-2/O-2 cell activity due to significant reduction in ohmic resistivity. Also, it is observed that the use of sPAni slightly improves the cell performance due to an increased probability of the triple phase contact and it can lead to superior physicochemical properties such as conductivity and thermal stability. (c) 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40314.