Membranes 2012, 2(2), 325-345; doi:10.3390/membranes2020325
Article

NMR and Electrochemical Investigation of the Transport Properties of Methanol and Water in Nafion and Clay-Nanocomposites Membranes for DMFCs

1 Department of Chemistry, University of Calabria, 87036 Rende (CS), Italy 2 CNR-ITAE Institute, via Salita S. Lucia sopra Contesse, 5, 98126 Messina, Italy
* Author to whom correspondence should be addressed.
Received: 18 May 2012; in revised form: 8 June 2012 / Accepted: 12 June 2012 / Published: 20 June 2012
(This article belongs to the Special Issue Membranes for Electrochemical Energy Applications)
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Abstract: Water and methanol transport behavior, solvents adsorption and electrochemical properties of filler-free Nafion and nanocomposites based on two smectite clays, were investigated using impedance spectroscopy, DMFC tests and NMR methods, including spin-lattice relaxation and pulsed-gradient spin-echo (PGSE) diffusion under variable temperature conditions. Synthetic (Laponite) and natural (Swy-2) smectite clays, with different structural and physical parameters, were incorporated into the Nafion for the creation of exfoliated nanocomposites. Transport mechanism of water and methanol appears to be influenced from the dimensions of the dispersed platelike silicate layers as well as from their cation exchange capacity (CEC). The details of the NMR results and the effect of the methanol solution concentration are discussed. Clays particles, and in particular Swy-2, demonstrate to be a potential physical barrier for methanol cross-over, reducing the methanol diffusion with an evident blocking effect yet nevertheless ensuring a high water mobility up to 130 °C and for several hours, proving the exceptional water retention property of these materials and their possible use in the DMFCs applications. Electrochemical behavior is investigated by cell resistance and polarization measurements. From these analyses it is derived that the addition of clay materials to recast Nafion decreases the ohmic losses at high temperatures extending in this way the operating range of a direct methanol fuel cell.
Keywords: self-diffusion; NMR; DMFC; nanocomposites; clays; transport properties; methanol

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MDPI and ACS Style

Nicotera, I.; Angjeli, K.; Coppola, L.; Aricò, A.S.; Baglio, V. NMR and Electrochemical Investigation of the Transport Properties of Methanol and Water in Nafion and Clay-Nanocomposites Membranes for DMFCs. Membranes 2012, 2, 325-345.

AMA Style

Nicotera I, Angjeli K, Coppola L, Aricò AS, Baglio V. NMR and Electrochemical Investigation of the Transport Properties of Methanol and Water in Nafion and Clay-Nanocomposites Membranes for DMFCs. Membranes. 2012; 2(2):325-345.

Chicago/Turabian Style

Nicotera, Isabella; Angjeli, Kristina; Coppola, Luigi; Aricò, Antonino S.; Baglio, Vincenzo. 2012. "NMR and Electrochemical Investigation of the Transport Properties of Methanol and Water in Nafion and Clay-Nanocomposites Membranes for DMFCs." Membranes 2, no. 2: 325-345.

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