The rejuvenation of alternative energy research is readily apparent when considering the fuel cell industry. After decades of little significant change in materials used in the cells, fuel cells -- both hydrogen and methanol -- are undergoing a materials revolution.
A basic fuel cell has three components. The first is the anode electrode, which is attached to a membrane, typically coated in catalyst, which is selectively permeable and exposes reactants to each other. The next part is the electrolyte, most commonly Nafion in methanol fuel cells. The final component is the cathode, an electrode attached to another selectively permeable membrane.
By reactions occurring at the cathode and anode, a voltage difference is yielded, which is how the fuel cell makes power. DailyTech recently reported on a breakthrough in the membranes attached to the electrodes, something which has been relatively unchanged for a long time. Another major breakthrough in the catalyst coating these membranes was also reported.
Now researchers have found a way to improve the third component, the electrolyte layer, for methanol fuel cells. MIT engineers have improved a methanol fuel cell's power output by 50 percent by using a new material. More importantly, they report that the new material is significantly cheaper than the current electrolyte material.
Paula T. Hammond, Bayer Professor of Chemical Engineering lead the MIT team in their research. She says the new material is very promising, not only for fuel cells, but also for traditional batteries, as they use a layer of electrolyte as well. She states, "Our goal is to replace traditional fuel-cell membranes with these cost-effective, highly tunable and better-performing materials."
Hammond authored a work with Avni A. Argun, a postdoctoral chemical engineering associate, and J. Nathan Ashcraft, a graduate student, which appeared recently in the Advanced Materials journal. Their new material is less permeable than the commonly used current electrolyte layer, Nafion, which allows methanol to seep across it, lowering the cell's efficiency.
The new MIT electrolyte film takes advantage of a new materials assembly process known as layer-by-layer assembly. The new approach allows for more careful construction of a chemical surface. Says Hammond, "We were able to tune the structure of [our] film a few nanometers at a time."
The new material has two orders of magnitude less permeability as a result and compares favorably to Nafion in its proton mobility character. The MIT researchers say that despite the new process, the material will be cheaper to make then the old one.
In the test researchers coated a Nafion film with the new material and observed a 50 percent increase in power. Hammond and her team are now looking at moving ahead and using the film independently to entire replace the Nafion layer. They have been working on developing thin stand alone films, much like plastic wrap.
Hammond's team focuses on methanol fuel cells for several reasons. First methanol is easier to make, as it does not require alcohol to be broken down into hydrogen. Secondly as it is a liquid fuel as opposed to hydrogen, which is a gas, it does not need to be stored under pressure and is less flammable than hydrogen. It also has an attractively high energy density.
While it may seem like the components of a fuel cell are advancing piece by piece independently and are not yielding sufficient commercialization, we can be rest assured that these developments will soon see their way into the next generation of fuel cells that hit the market.
And it may be sooner as opposed to later. Next year several companies are set to release commercial methanol fuel cells to a consumer -- a first.
quote: We are going to have some kind of shortage or crisis in the next couple of years and it's going to cause prices for everything to spiral upwards.