Self-Humidifying Electrolyte Membranes for Fuel Cells

Abstract

We propose self-humidifying polymer electrolyte membranes (PEM) with highly dispersed nanometer-sized Pt and/or metal oxides for polymer electrolyte fuel cells (PEFCs) operated with dry H2 and O2. The Pt particles were expected to suppress the crossover by the catalytic recombination of H2 and O2, while the oxide particles false(TiO2false) that have hygroscopic property were expected to adsorb the water produced at Pt particles together with that produced at the cathode reaction and to release the water once the PEM needs water. The preparation protocol of TiO2 nanoparticles in a commercial Nafion 112 membrane via in situ sol-gel reactions was developed, resulting in a transparent membrane with uniform distribution of TiO2 in the PEM. Water adsorbability increased more than two times by dispersing only 2 wt % TiO2 in the PEM. That newly prepared TiO2 -PEM cooperated with highly dispersed Pt nanoparticles (Pt- TiO2 -PEM) was confirmed to perform a self-humidifying operation in a PEFC with dry H2 and O2. © 2002 The Electrochemical Society. All rights reserved.

On the proton conductivity of Nafion–Faujasite composite membranes for low temperature direct methanol fuel cells

“…Many types of inorganic fillers have been reported to decrease the methanol crossover of Nafion membrane. Although some improved electrochemical characteristics have been reported, especially when intrinsically proton conducing fillers have been used, most of the composite membranes have lower proton conductivity than the pure Nafion membrane [9][10][11][12][13][14][15][16][17][18][19].…”

Increases in the proton conductivity and selectivity of proton exchange membranes for direct methanol fuel cells by formation of nanocomposites having proton conducting channels

“…Sacrifices in the mechanical properties and an increase in methanol permeability usually accompany high sulfonic acid concentra-tions [14]. Stabilization or mitigation of methanol permeability can be achieved through polymer blending [15], cross-linking [16] and formation of nanocomposites [17][18][19][20]. However, most of the reported approaches adversely affect the proton conductivities.…”

Investigation of Advanced Hybrid PEM Based on Sulfonyl Fluoride PFSA and Grafted Inorganic Nanoparticles

“…Wet mass-Dry mass Water Uptake (%)= ×100 Dry mass [ 3 ] Volume change or dimensional swelling was determined by measuring the thickness, width and length of wet and dried membranes (in H+ form). Dimensions of dried membranes were determined by drying them in a vacuum oven at 80°C overnight.…”