Promoted as an alternative fuel source for vehicles traditionally powered with gas, fuel cells have led a short and expensive life. Depending on size, these cells can power anything, from small cars to large buildings, from hospital generators to the space shuttle. To date, fuel cells have required the use of platinum, an expensive material, in their construction. Researchers have discovered a new, more cost-effective method of constructing these cells, potentially providing a breakthrough for alternative fuel and power generation.
Fuel cells of all sizes have a similar construction method, with three segments that are layered together: an anode, an electrolyte, and a cathode. Chemical reactions at the interfaces between the layers consume fuel, then create water or carbon dioxide, and provide an electric current. The current, referred to as the load, is used to power any of a variety of electrical devices or vehicles. Fuel cells such as this are generally powered by hydrogen, but they can also utilize methanol and other fuel sources.
The most cost-prohibitive issue with fuel cells is that platinum powder is used to break the fuel source (hydrogen, methanol, etc.) down into electrons and ions. However, engineers at Case Western Reserve University have developed a new cathode production method utilizing carbon. This method avoids the need for platinum and thus radically cuts the associated production costs for each individual cathode and fuel cell. For reference, platinum costs roughly $65,000 per kilogram, while carbon costs around $100 per kilogram.
The drastic reduction in production costs is matched by outstanding performance. Platinum, referred to as a catalyst when used within a fuel cell, is responsible for the cell’s overall energy output. The new carbon-based cathodes produce power comparable with fuel cells utilizing platinum catalysts while offering a number of benefits over the older model.
The new production method utilizes carbon nanotubes coated with a polymer solution. The carbon tubes are placed in a water solution containing the polymer polydiallyldimethylammonium chloride. The polymer coats the surface of the nanotube, creating a net positive charge by pulling an electron away from the carbon surface. The nanotubes are then used as catalysts within the fuel cells, and they provoke an oxygen-reduction reaction. This reaction produces power as the cathodes combine hydrogen and oxygen.
During testing in an alkaline fuel cell, carbon cathodes demonstrated they could produce a similar power output as compared with fuel cells incorporating platinum catalysts. However, the carbon catalyst is more stable and durable. Platinum loses its catalytic potential over time, while carbon does not; it will retain its efficiency for the lifetime of the fuel cell.
Additionally, the new cells resist contamination from carbon monoxide poisoning, and they also resist crossover effects related to the use of methanol for the cell’s fuel supply. Methanol, a less expensive alternative to hydrogen as a power source, reduces the effectiveness of platinum catalysts as the fuel crosses from the anode to the cathode within the fuel cell.
Engineers associated with the project have published their work to date in the Journal of the American Chemical Society and postulate that further improvements can be made to the nanotubes’ power output. In practical terms, this discovery makes plausible the scenario of everyone using fuel cells to power their automobiles and residential homes. Fuel cells have been cost-prohibitive or materials-prohibitive since their inception, and this design not only speeds up production, but also reduces costs to a price that the average consumer can afford.
In addition to this, carbon-based fuel cells have the potential to reduce public infrastructure cost. The cells can be used to power buses, cellular phone towers, hospitals, and government facilities, among other uses. This will not only reduce our dependence on a nation-wide power grid, it will also facilitate a reduction in the amount of oil, gas, and coal required to operate these systems. Residential homes could also run on these fuel cells, losing the need for solar or wind power in order to get off the grid.
The creation of a low-cost fuel cell is a significant breakthrough in the search for alternative fuel sources. While other forms of alternative power may be insufficient for our needs or simply too pricey for many families to afford, this inexpensive type of fuel can be made readily available to large numbers of consumers. Carbon is the most plentiful element on Earth, and it makes perfect sense to use an abundant and readily available substance to provide a strong source of power for our homes.