Shruti Prakash

Microfabricated Fuel Cell with Composite Glass∕Nafion Proton Exchange Membrane

The performance of microfabricated fuel cells with Nafion-coated glass composite membranes was investigated. The performance and durability of the fuel cells with silica glass membranes were improved by casting a thin film of Nafion on the anode side of the thin, phosphosilicate glass membrane. Nafion increased the strength of the glass membrane and provided a better chemical environment for the air-cathode. The use of a two-layer anode catalyst improved the anode performance by increasing the catalyst loading while maintaining catalyst porosity for proton transport. The performance, durability, and fuel utilization of the fuel cells using hydrogen and methanol as fuel were studied.

Platinum-Glass Composite Electrode for Fuel Cell Applications

Thin-film electrodes for a low-power direct methanol fuel cell (DMFC) were prepared by incorporating carbon-supported Pt nanoparticles (Pt/C) into a silicon dioxide glass matrix. The SiO 2 matrix was prepared via a sol-gel technique where tetraethyl orthosilicate (TEOS) was hydrolyzed by H 2 O in the presence of methanol. The Pt/C was stirred into the sol and the resulting mixture was applied to a glass membrane substrate and cured. The resulting films were ∼ 2 μm thick. Scanning electron microscopy (SEM) images indicate that the Pt/C was well dispersed, forming glass-separated conductive islands with sheet resistances in excess of 5000 Ω/□. The catalyst islands were interconnected into a conductive sheet by electrolessly depositing platinum from an aqueous plating bath. The Pt/C-SiO 2 glass composite thin-film electrodes showed high methanol oxidation peak currents of ∼ 180 mA/cm 2 when immersed in 0.5 M H 2 SO 4 , 0.5 M methanol electrolyte. The composite electrode was also applied to the anode of a 1 cm 2 passive DMFC and compared to an equivalent passive DMFC with a traditional Nafion-based Pt anode electrode with 10 M MeOH at room temperature. The composite electrode DMFC showed a 50 mV higher open-circuit voltage than the Nafion electrode cell, and the current density was also modestly improved.