Sep 30 2020
Professor Mohamed Mohamedi along with a team of researchers from the Institut national de la recherche scientifique (INRS) has developed a green membraneless fuel cell that utilizes atmospheric oxygen.
Image Credit: INRS
The results of this ground-breaking microfluidic application—a first in Canada—were reported in Renewable and Sustainable Energy Reviews on September 8th, 2020.
Traditional fuel cells are widely used. They drive electric cars seen on today's roads and were integrated into the computers used in the 1969 Apollo moon landing. Such fuel cells lose voltage as they are used and ultimately cease working.
This occurs because alcohol molecules (ethanol or methanol) in the anode compartment of the fuel cell travel across the membrane that separates them from the cathode section. Within the cathode compartment, oxygen molecules react with the alcohol resulting in voltage loss.
Several researchers have futilely attempted to create a membrane that blocks alcohol molecules from traveling through it. Professor Mohamed Mohamedi, the study’s lead author adopted another approach: creating a membraneless fuel cell.
His unique solution costs less and involves fewer steps to develop; however, it fails to resolve a core challenge.
When the membrane is removed, the methanol or ethanol reacts with the oxygen, just like in conventional fuel cells. To prevent voltage drops, we had to develop selective electrodes in the cathode compartment. These electrodes, designed by doctoral student Juan Carlos Abrego-Martinez, remain inactive in the presence of alcohol molecules but are sensitive to the oxygen that generates electricity.
Mohamed Mohamedi, Study Lead Author and Professor, INRS
He observed another exclusive property of this membraneless fuel cell: it utilizes the atmospheric oxygen around it.
From Model to Prototype
To build a working prototype, the first step used by the researchers was to run numerical simulations produced by Alonso Moreno Zuria, a postdoctoral fellow at INRS and the study’s lead author. With the help of computer modeling, the researchers tested various configurations of selective electrodes in the fuel cell.
Conventional fuel cells are like sandwiches, with the membrane in the middle. We chose instead to work on a single-layer design. We had to determine how to arrange and space the electrodes to maximize fuel use while keeping ambient air oxygen concentration in mind.
Mohamed Mohamedi, Study Lead Author and Professor, INRS
As soon as the scientists decided on a configuration, they tried out a prototype that became a proof of concept. The membraneless fuel cell supplied an LED with energy for four hours using just 234 μl of methanol. The team is keen to improve the fuel cell so that it can employ a greener fuel—ethanol—that can be made from agricultural waste and biomass. Ethanol also delivers more power per corresponding unit of volume.
The researchers believe that the fuel cell would drive microsystems like air pollution sensors, and portable electronics like cellular phones. In contrast to traditional batteries that store electricity and have to be recharged, fuel cells continue to generate energy as long as fuel is available.
This energy supply method is particularly effective when recharging is not possible. Imagine being in the middle of the desert, without electricity. You could recharge your mobile phone using a small capsule of ethanol that you connect to the device.
Mohamed Mohamedi, Study Lead Author and Professor, INRS
This groundbreaking technology has already drawn the attention of industry, although the researchers are still at the prototype stage.
The team was received financial support from the Natural Sciences and Engineering Research Council (NSERC), the Quebec Centre for Advanced Materials (QCAM), the UNESCO/MATECSS chair, Consejo Nacional de Ciencia y Tecnología (CONACYT, Mexico), and Científicos Mexicanos en el Extranjero.
Journal Reference
Moreno, A., et al. (2020) Prospects of membraneless mixed-reactant microfluidic fuel cells: Evolution through numerical simulation. Renewable and Sustainable Energy Reviews. doi.org/10.1016/j.rser.2020.110045.