We have developed a groundbreaking power system that leverages current MIT research to turn scrap aluminum into a highly efficient, safe fuel source.
Aluminum has an incredibly high energy density, double that of gasoline and an order of magnitude greater than lithium-ion. However, an oxide layer forms on its surface when in contact with air, preventing it from reacting. Processes have been developed to circumvent this in order to utilize this energy density in applications such as rocket fuels, but they are very dangerous and create serious risks of combustion.
In recent years, students at MIT have developed a method for safely activating aluminum by treating it with 2% gallium and indium. This treatment bypasses the oxide layer on the surface and allows the aluminum to react exothermically with water to produce hydrogen, and aluminum oxyhydroxide. We can now take advantage of a reaction that has the energy density of rocket fuel, with high levels of control and safety. Additionally, this fuel can be made easily and cheaply from scrap aluminum, while producing recyclable byproducts.
We created a 3kW Emergency Power Supply that generates electricity from this fuel. In this system, the aluminum reacts with tap or waste water, and releases its energy in roughly equal parts heat and hydrogen. The heat is then dissipated through a radiator and the hydrogen is put into a high efficiency hydrogen fuel cell which generates electricity. This allows for a simple, small, and highly energy dense power system for emergency situations. The reaction does not produce any toxic gasses or carbon emissions, and can therefore be run in enclosed spaces safely (without worry of inhalation hazards.)
We then moved forward to even higher power outputs: fueling a BMW with aluminum. This year, we developed a 10kW aluminum fueled range extender for a BMW i3. Similar to the Emergency Power Pack, the aluminum was reacted with water to produce hydrogen and the hydrogen was fed into a fuel cell. This power system proved that aluminum fuel can both react and be controlled even at high rates. It demonstrated its ability to produce power on the scale needed for vehicle propulsion, or building scale emergency generators.
Our current challenge is to develop this fuel even further, and create more practical, higher efficiency, aluminum fueled electric generators. We are developing a reactive liquid fuel, made from an aluminum-oil suspension, to allow for a simpler, continuous reaction system, and more precise fuel metering. Additionally, developing a system which can utilize the heat of the reaction, rather than dump it as waste heat, has the potential to increase the system efficiency even further.
Imagine a hospital with safe generators that last twice as long, or a home basement generator without fear of carbon monoxide poisoning. With continued funding, we can continue the research and development of such aluminum systems, and provide a significant jump forward in generator technologies.