Advanced Mesostructured Hybrid Silica−Nafion Membranes for High-Performance PEM Fuel Cell

Abstract

Organic-inorganic hybrid membranes of Nafion and mesoporous silica containing sulfonic acid groups were synthesized using the sol-gel process with the goal of increasing the proton conductivity and water retention at higher temperatures and lowering relative humidities as well as improving the dimensional stability. These hybrid membranes were prepared via in situ co-condensation of tetraethoxysilane and chlorosulfonylphenethylsilane via self-assembly route using organic surfactants as templates for the tuning of the architecture of the silica or hybrid organosilica components. In this paper, we describe the elaboration and characterization of new hybrid membranes all the way from the precursor solution to the evaluation of the fuel cell performances. These hybrid materials were extensively characterized with the determination of their physicochemical and electrochemical properties. The membrane containing functionalized silica showed a higher ionic exchange capacity and greater water management than standard Nafion. The hybrid membranes showed improved proton conductivity at 95 °C and over the whole range of relative humidity in comparison to recast Nafion and Nafion 112 membranes.

New nanocomposite proton conducting membranes based on a core–shell nanofiller for low relative humidity fuel cells

“…15 and 25 mS cm 21 , respectively. 39 The hybrid membrane is also better able to absorb the available water, which leads to significantly better performance at low hydration degrees because the membrane maintains sufficient proton conductivity. However, the [Nafion/(ZrTa) Y ] membrane is also less capable of removing excess water, e.g., at high back pressure, high a H 2 O and high current density values where a significant amount of water is produced by fuel cell operation.…”

Modification of chitosan membranes with nanosilica particles as polymer electrolyte membranes

“…In addition, another factors that affects this is the hydrophilic properties of the Si-OH groups in silica. The high silica composition in the membrane matrix increases the water charges relatively due to the amount of Si-OH groups, and the amount of water that is absorbed through the pores [16].…”

Embedding of Hollow Polymer Microspheres with Hydrophilic Shell in Nafion Matrix as Proton and Water Micro-Reservoir

“…Incorporation of inorganic particles (e.g., silica, zeolites) into Nafion membrane matrix to enhance hygroscopy of membrane is representative of earlier efforts [4][5][6][7][8][9][10]. In the resulting composite membrane, hydrogen bonding between the surface hydroxyl group of inorganic filler and the pendant sulfonic acid group (-SO 3 H) of Nafion assists the dispersion of filler particles in the host matrix [11,12]. Grafting hydrophilic oligomeric chains to inorganic particles [3][4][5][6][7][8][9][10][11][12][13][14][15] has furthered the preparation technique of Nafion nanocomposite membranes.…”

“…In the resulting composite membrane, hydrogen bonding between the surface hydroxyl group of inorganic filler and the pendant sulfonic acid group (-SO 3 H) of Nafion assists the dispersion of filler particles in the host matrix [11,12]. Grafting hydrophilic oligomeric chains to inorganic particles [3][4][5][6][7][8][9][10][11][12][13][14][15] has furthered the preparation technique of Nafion nanocomposite membranes. With the aim of achieving the forestated goal, use of hydrophilic hollow polymer spheres (HPS) as filler is apparently more attractive [16][17][18][19][20][21] because this particulate structure possesses larger interior space for storing water and the porous hydrophilic polymeric shell prevents quick evaporation of water while the membrane is subjected to dehydration [22,23].…”