The basic operation starts with the sodium borohydride flowing through the anode or fuel side of the membrane electrode assembly (MEA). This is represented by the two black catalysts and the red NAFION membrane in the figure above. Hydrogen peroxide then naturally flows through the oxidant or cathode side of the cell. Hydrogen ions break off of the sodium borohydride and then move through the MEA to react with the hydrogen peroxide, forming water. In the process, they break their bonds and free the electrons associated with those bonds. This creates a potential difference across the cell.
Advantages of Fuel Cells
Liquid-liquid closed loop system: There are more complications present in a fuel cell system when hydrogen needs to be taken out of other chemicals and gases are used. They often need to be pressurized, and in the case of hydrogen are very prone to escaping the manifolding. When gases are used, the stack needs to monitor the ionomer moisture. If such membranes are not kept hydrated, they lose their ability to conduct protons. A liquid by virtue of its structure just has more energy density than that same substance as a gas.
Liquid Fuel Infrastructure already in place: Our energy economy is a liquid one. It is easier to transition to an energy economy that has a liquid as its basis rather than gas.
High Energy Density: The graph of volumetric vs. gravimetric energy density, shows the reactants used have a high energy density. This is due to both the nature of the reaction and the use of liquids instead of gases.
Minimal use of noble metals to thwart high costs and poisoning: Many fuel catalysts use noble metals to optimize power density. Noble metals work well, but tend to be rare and very expensive. Swift wants to stay away from them for these reasons.
No heavy structural tanks to store pressurized gasses: Cells that use gases need to store those gases in pressurized vessels to have decent energy density. This can add quite a bit of weight to a system. Also, this increases the complexity and number of systems necessary, and is a safety issue. Hydrogen under pressure can make it a threat in terms of flammability. It is even possible that in the event of a sudden tear in a high pressure tank, the static discharge could ignite the gas.
No Harmful Emissions: The Swift FCS has many advantages over petroleum based power generation. The only gas generated in the reaction is a trivial amount of hydrogen, which of course is not harmful. Via the overall chemical reaction, one can also see that the other products yielded likewise are not dangerous.
High Efficiency: In terms of efficiency, ICEs again can only achieve slightly less than 50%, where a fuel cell operates usually in a much higher range.
More Applications: Swift’s FCS is not simply limited to use in aircraft. It’s worth noting that it could be used in stand alone power generation, the automotive industry, space craft, individual infantry soldiers battery replacements and laptop battery replacements. The amount of applications are quite immense.
Renewability of Fuel: Going back to the reaction of the system, the products are sodium metaborate and water, both of which can be converted back into their respective original reactants. The water of course can be made back into H2O2 and the sodium metaborate can be made back into NaBH4. This can be done via chemical means or via electrolysis.
Availability of Fuel: One obstacle this type of fuel cell has like others, is the creation of its infrastructure. Using liquids makes this an easier change than say for a hydrogen cell, but the NaBH4 will take some effort to bring markets and bring the price down. The real advantage however comes when it has fully arrived in those markets as regeneration will be cheaper than having to truck new fuel to stations. Refueling would become trading in old products of the reaction for the new reactants at stations where the products could be continually regenerated. This is a much more stable and cheap system once in place than petroleum infrastructures.
Energy Independence: If the Swift FCS became a large part of power generation, this would lessen the need for foreign oil, a huge benefit.
Light Weight: The reactants being used have a high energy density making it feasible to use in applications such as flight.
Safety/Low Operating Temperatures and Pressures: Instead of carrying around a flammable fuel, the eVia system carries reactants that are not. This is made even less of a threat in that the FCS operates at conditions slightly higher than ambient temperature and pressure. Vehicles can additionally arrange their power plants so that the reactants are placed near each other so that in the event of a catastrophic accident, they will react and not get on any passengers/bystanders. The reactants themselves pose little harm to people, especially where they’re dissolved in water in the system.