Thermal curing of PBI membranes for high temperature PEM fuel cells

Publication: Research - peer-reviewJournal article – Annual report year: 2012

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@article{68b4969caf2e4e9cb78a6fb96245d6f6,
title = "Thermal curing of PBI membranes for high temperature PEM fuel cells",
publisher = "Royal Society of Chemistry",
author = "David Aili and Cleemann, {Lars N.} and Qingfeng Li and Jensen, {Jens Oluf} and Erik Christensen and Bjerrum, {Niels J.}",
year = "2012",
doi = "10.1039/c2jm14774b",
volume = "22",
number = "12",
pages = "5444--5453",
journal = "Journal of Materials Chemistry",
issn = "0959-9428",

}

RIS

TY - JOUR

T1 - Thermal curing of PBI membranes for high temperature PEM fuel cells

A1 - Aili,David

A1 - Cleemann,Lars N.

A1 - Li,Qingfeng

A1 - Jensen,Jens Oluf

A1 - Christensen,Erik

A1 - Bjerrum,Niels J.

AU - Aili,David

AU - Cleemann,Lars N.

AU - Li,Qingfeng

AU - Jensen,Jens Oluf

AU - Christensen,Erik

AU - Bjerrum,Niels J.

PB - Royal Society of Chemistry

PY - 2012

Y1 - 2012

N2 - Phosphoric acid doped polybenzimidazole (PBI) has emerged as one of the most promising electrolyte materials for proton exchange membrane (PEM) fuel cells operating under anhydrous conditions at temperatures of up to 200 °C. The limited long-term durability of the membrane electrode assemblies (MEAs) is currently hampering the commercial viability of the technology. In the present study, thermoset PBI membranes were prepared by curing the membranes under inert atmosphere at temperatures of up to 350 °C prior to the acid doping. The systematic membrane characterizations with respect to solubility, phosphoric acid doping, radical-oxidative resistance and mechanical strength indicated that the PBI membranes were irreversibly cured by the thermal treatment. After curing, the PBI membranes demonstrated features that are fundamental characteristics of a thermoset resin including complete insolubility, high resistance to swelling and improved mechanical toughness. Additionally, the thermal treatment was found to increase the degree of crystallinity of the membranes. The improved physicochemical characteristics of the membranes after curing were further illustrated by a dramatically improved long-term durability of the corresponding fuel cell MEAs. During continuous operation for 1800 h at 160 °C and 600 mA cm−2, the average cell voltage decay rate of the MEA based on the cured membrane was 43 μV h−1. This should be compared with an average cell voltage decay rate of 308 μV h−1 which was recorded for the MEA based on its non-cured counterpart.

AB - Phosphoric acid doped polybenzimidazole (PBI) has emerged as one of the most promising electrolyte materials for proton exchange membrane (PEM) fuel cells operating under anhydrous conditions at temperatures of up to 200 °C. The limited long-term durability of the membrane electrode assemblies (MEAs) is currently hampering the commercial viability of the technology. In the present study, thermoset PBI membranes were prepared by curing the membranes under inert atmosphere at temperatures of up to 350 °C prior to the acid doping. The systematic membrane characterizations with respect to solubility, phosphoric acid doping, radical-oxidative resistance and mechanical strength indicated that the PBI membranes were irreversibly cured by the thermal treatment. After curing, the PBI membranes demonstrated features that are fundamental characteristics of a thermoset resin including complete insolubility, high resistance to swelling and improved mechanical toughness. Additionally, the thermal treatment was found to increase the degree of crystallinity of the membranes. The improved physicochemical characteristics of the membranes after curing were further illustrated by a dramatically improved long-term durability of the corresponding fuel cell MEAs. During continuous operation for 1800 h at 160 °C and 600 mA cm−2, the average cell voltage decay rate of the MEA based on the cured membrane was 43 μV h−1. This should be compared with an average cell voltage decay rate of 308 μV h−1 which was recorded for the MEA based on its non-cured counterpart.

U2 - 10.1039/c2jm14774b

DO - 10.1039/c2jm14774b

JO - Journal of Materials Chemistry

JF - Journal of Materials Chemistry

SN - 0959-9428

IS - 12

VL - 22

SP - 5444

EP - 5453

ER -