A team from the School of Materials Science & Engineering at Georgia Tech has found the chemical triazole is significantly more effective than similar chemicals used to increase conductivity and reduce moisture dependence in polymer membranes. The findings were published in the Journal of the American Chemical Society.
"Triazole will greatly reduce many of the problems that have prevented polymer fuel cells from making their way into things like cars, cell phones and laptops," said research team leader Meilin Liu.
"It's going to have a dramatic effect."
Fuel cells produces electricity by converting hydrogen and oxygen into water via a proton exchange membrane that conducts protons (positively charged ions) but blocks electrons.
Current PEMs have an operating temperature so low that trace amounts of carbon monoxide in hydrogen can poison the fuel cell's platinum catalyst, requiring an expensive purification process that makes fuel cells uneconomical compared to fossil fuel power.
The Georgia team has found the high operating temperature allowed by a membrane containing triazole means the fuel cell can tolerate much higher levels of carbon monoxide in the hydrogen fuel and do away with the purification costs.
Polymer fuel cell membranes must also be kept cool so membranes can retain moisture needed to conduct protons, forcing them to operate at temperatures below 100C and use complex design features to regulate hydration.
By using PEMs containing triazole, Liu's team has been able to operate PEM cells above 120C, eliminating the need for water management systems and using a simple cooling system that dramatically reduces cost and complexity.
"We're using the triazole to replace water," Liu said. "By doing so, we can bring up the temperature significantly."
The Georgia team has also found that triazole is a very stable chemical, allowing for stable fuel cell operating conditions, and it believes that in the near future they will be able to boost temperatures past 120C, ushering in the potential for ultra low-cost, emission-free power that is simple enough to use in cars and consumer electronics.
