Scientists at Northwestern University have developed a pocket-sized fuel cell that can harvest energy produced by soil microorganisms in both wet and dry states with record efficiency.
This technology, powered entirely by the ground, is the size of a paperback book and could power underground sensors used in precision agriculture and green infrastructure.
It can also provide a sustainable alternative to batteries, which contain toxic and flammable chemicals that negatively impact the environment and contribute to the creation of e-waste.
New fuel cell
Scientists tested the new fuel cell by using it to power sensors that measure soil moisture and detect touch, which could be useful for tracking animals.
They also equipped the sensor with a small antenna that enables wireless communication and transmits data to a nearby base station by reflecting existing radio frequency signals.
The fuel cell works in both dry and wet conditions and is 120% more powerful than comparable technologies.
In recent years, farmers have adopted precision farming to improve their crop yields. This approach relies on accurately measuring soil moisture, nutrient and pollutant levels to make informed decisions that can improve plant health.
However, this requires a large distributed network of electronic devices that can continuously collect environmental data.
Collect energy from the ground
To solve this problem, researchers like Wells, Yen and their colleagues are exploring the possibility of harvesting energy from the existing environment. Ian explains that they can generate energy from land that farmers already control.
Ian and his team began a two-year journey to develop a practical and reliable terrestrial MFC. They created and compared four different versions. They collected performance data for each design for nine months, ultimately testing the most effective prototype in an outdoor garden. The secret of success is the geometry, which deviates from traditional design.
Instead of a parallel anode and cathode, the winning fuel cell uses a perpendicular design: the anode is made of carbon felt and the cathode is made of an inert conductive metal. This design works well in both dry and humid environments.
The device is constructed vertically so that the top is level with the floor. The device features a 3D printed lid at the top to keep out dirt and a vent at the top that allows constant air circulation.
The lower end of the cathode remains below the surface and remains moist thanks to the surrounding soil moisture. It is covered with waterproof material so that it can breathe during floods.
The device generates 68 times the energy needed to operate the sensors and can withstand large fluctuations in soil moisture.
According to the researchers, you can purchase all of the components of their MFC device to mount this fuel cell in the ground at your local hardware store.
Next, they plan to develop soil-based MFCs made from fully biodegradable materials. Both projects avoid complex supply chains and the use of minerals from conflict areas.
With information from: