A groundbreaking discovery by scientists at the Massachusetts Institute of Technology (MIT) could revolutionize clean energy production using materials as simple as old soda cans and seawater. By harnessing the power of aluminum and seawater to generate hydrogen fuel, this innovative approach could have far-reaching implications for sustainable energy systems, especially in maritime applications.

Aluminum, a material most commonly found in soda cans and foil wraps, is often overlooked for its potential in energy production. However, when treated correctly, aluminum can react with water to produce hydrogen gas—a clean, efficient fuel that only releases water vapor when burned. Although the basic chemical reaction between aluminum and water has been known for some time, scaling it up for practical and cost-effective use has been a significant challenge—until now.

MIT’s research team, led by Aly Kombargi, has developed a novel method for overcoming this obstacle by using a special coating of liquid metal made from gallium and indium (known as eGaIn) to trigger the hydrogen-producing reaction in seawater. The issue with aluminum is that, upon exposure to air, it forms a protective oxide layer that prevents the reaction from occurring, which is why dropping a soda can into water doesn’t result in hydrogen production.

The team discovered that the natural saltiness of seawater could be key to solving this problem. The ions in seawater form what’s known as an “electrical double layer” around the liquid metal droplets, preventing them from breaking apart during the reaction. This mechanism allows the researchers to recover over 90% of the gallium and indium coating after use, which is crucial given the high cost and rarity of these metals.

In a surprising twist, the addition of coffee grounds was found to accelerate the reaction. The team’s lab investigation revealed that caffeine’s active ingredient, imidazole, is the primary accelerant in the process. “That was our big win,” said Kombargi. “We had everything we wanted: efficient hydrogen production and the ability to recover the liquid metal coating.”

Testing their system with seawater collected from Revere Beach near Boston, the team found that the addition of imidazole sped up the reaction while maintaining high recovery rates of the liquid metal. By pre-heating the seawater to around 80°C (176°F), they could produce hydrogen in under 10 minutes—much faster than previous methods, which could take several hours.

To ensure the process wasn’t just a lab curiosity, the team scaled up their reaction, using 50 grams of aluminum and 5 liters of seawater, and still achieved similar efficiency. The next step in their research involves developing a small-scale reactor for use in marine vessels and underwater vehicles. This system would store recycled aluminum pellets, along with small amounts of gallium-indium and imidazole, which could be mixed with seawater to generate hydrogen on demand.

One of the most promising aspects of this technology is its ability to eliminate the need for storing and transporting hydrogen gas, which is both volatile and difficult to manage. “This is very interesting for maritime applications like boats or underwater vehicles,” explains Kombargi. “You wouldn’t need to carry seawater; it’s readily available. And instead of carrying hydrogen gas, you would transport aluminum as the fuel and just add water to produce hydrogen when needed.”

The researchers have calculated that a reactor holding about 40 pounds of aluminum pellets could power a small underwater glider for approximately 30 days. This approach could significantly reduce the logistical and safety challenges associated with hydrogen fuel storage and transport, while also providing a reliable and sustainable source of clean energy.

With further development, this technology could pave the way for new applications in clean energy, not just in maritime industries, but potentially in other sectors as well, making it a promising step toward a more sustainable and hydrogen-powered future.

By Impact Lab