A flexible all-inorganic fuel cell membrane with conductivity above Nafion, and durable operation at 150 °C

Abstract

The search for fuel cell membranes has focused on carbon backbone polymers, among which Nafion seems to best survive the most severe of the degradation mechanismsattack by peroxide radicals. Less attention has been given to inorganic membranes because of their generally inflexible nature and lower conductivity, though some SiO 2-Nafion composites have shown improved properties. Nafion dominates, despite needing hydration, which then restricts operation to below 100ºC (so CO poisoning problems persist). Described herein is a low cost, flexible, and all-inorganic fiberglass reinforced gel membrane with conductivity exceeding that of Nafion at any temperature above 60ºC. Using Teflon fuel cells, maximum currents >1 Acm-2 and OCV of 1.03 V at 150ºC are demonstrated. No detectable loss of cell potential was observed over 24 hours during 50 mAcm-2 constant current operation at 120ºC while, at 150ºC and maximum power, the degradation rate is intermediate among other high conductivity H 3 PO 4-PBI type membranes. The structure of the membrane is deduced, mainly from 29 Si solid state-NMR. The-115 ppm resonance, which is extreme for Q 4 Si(O) structures, identifies a zeolite-like

Strengthening Phosphoric Acid Doped Polybenzimidazole Membranes with Siloxane Networks for Using as High Temperature Proton Exchange Membranes

“…They attributed the reasons to the enhanced PA adsorbing ability of membranes through electrostatic interactions. Meanwhile, Aili et al and Angell and co‐workers recently found that silicon oxides could improve the acid retention of membranes due to the formation of phosphosilicates. On the other hand, the introduced siloxane network might cause a separation of polymer backbones and created a more free volume for adopting phosphoric acid, which resulted in much more phosphoric acid uptake.…”

Design and Optimization of a Hyper-Branched Polyimide Proton Exchange Membrane with Ultra-High Methanol-Permeation Resistivity for Direct Methanol Fuel Cells Applications

“…Mechanical stability and thermal stability of the s -PI-PVDF composite membranes were subsequently analyzed for the consideration of long-term application in DMFC [50]. The mechanical strengths of the composite membranes are shown in Figure 7a.…”

Proton Conductive Channel Optimization in Methanol Resistive Hybrid Hyperbranched Polyamide Proton Exchange Membrane

“…Strong mechanical property of the membrane is one of the important demands to withstand high compression for MEA fabrication of PEMFC and DMFC applications [ 37 ]. The hybrid membranes exhibited good mechanical property from the stress-strain plots, as shown as displayed in Figure 6 a.…”