The human capabilities pack a whole lot together to enhance our experience, but when push comes to shove, nothing does the job quite like our skill of getting better on a consistent basis. This unfaltering commitment towards growing, no matter the situation, has brought the world some huge milestones, with technology emerging as quite a major member of the stated group. The reason why we hold technology in such a high regard is, by and large, predicated upon its skill-set, which guided us towards a reality that nobody could have ever imagined otherwise. Nevertheless, if we look beyond the surface for one hot second, it will become abundantly clear how the whole runner was also very much inspired from the way we applied those skills across a real world environment. The latter component, in fact, did a lot to give the creation a spectrum-wide presence, and as a result, initiated a full-blown tech revolution. Of course, the next thing this revolution did was to scale up the human experience through some outright unique avenues, but even after achieving a feat so notable, technology will somehow continue to bring forth the right goods. The same has turned more and more evident in recent times, and assuming one new discovery ends up with the desired impact, it will only put that trend on a higher pedestal moving forward.

The researching team at Northwestern University has successfully developed a new fuel cell, which comes decked up with an ability to harvest energy from microbes living in dirt. According to certain reports, the stated fuel cell is made to be the size of a standard paperback book, but despite not being very expansive in build, it can seamlessly leverage the mechanics of solar-powered technology to fuel underground sensors used in precision agriculture and green infrastructure. This means the cell can offer a far more sustainable and renewable alternative to batteries that are known for holding toxic flammable chemicals. To fully understand the significance behind such a development, we must start by acknowledging the chain of events that spelled its creation. You see, as of late, farmers are making a bigger pledge to adopted precision agriculture, treating it like a strategy to improve crop yields. Now, a fact worth mentioning here is how the given approach banks upon measuring precise levels of moisture, nutrients and contaminants in soil to make decisions that actually enhance crop health, and if we are to achieve that coveted precision, we must leverage a far-reaching electronic devices’ network, a network which in turn, has to continuously collect environmental data.

“If you want to put a sensor out in the wild, in a farm or in a wetland, you are constrained to putting a battery in it or harvesting solar energy,” said Bill Yen, who co-led the study. “Solar panels don’t work well in dirty environments because they get covered with dirt, do not work when the sun isn’t out and take up a lot of space. Batteries also are challenging because they run out of power. Farmers are not going to go around a 100-acre farm to regularly swap out batteries or dust off solar panels.”

In response, the researchers at Northwestern University came upon the possibility of using soil-based microbial fuel cells (MFCs) to harvest energy from the existing environment itself. First introduced way back in 1911, MFCs do operate a lot like batteries, with their anode, cathode and electrolyte. However, instead of using chemicals to generate electricity, they harvest electricity from bacteria that naturally donates electrons to nearby conductors. Hence, when these electrons flow from the anode to the cathode, it creates an electric circuit. Talk about the catch, making these microbial fuel cells operate without disruption requires constant hydration and oxygenation, a requirement which becomes all the more complicated once you factor in that they are buried underground.

“Although MFCs have existed as a concept for more than a century, their unreliable performance and low output power have stymied efforts to make practical use of them, especially in low-moisture conditions,” said Yen.

In their breakthrough, the researchers would notably develop a practical, reliable soil-based MFC. Specifically speaking, they created and compared four different versions of this new MFC. The comparison came only after collecting nine months worth of data on each design. Then, they tested it in an outdoor garden. Going by the available details, the best-performing prototype worked just as good in dry conditions as it did within a water-logged environment. It happened to be the case because cell’s geometry, rather than keeping anode and cathode parallel to each other, made an unconventional decision of trusting a perpendicular design. In the given design, the anode (made of carbon alt) is horizontal to the ground’s surface, whereas the inert-made cathode sits vertically atop the anode. Furthermore, even though the entire device is buried, the vertical design ensures that the top end is flush with the ground’s surface.  Aiding its case is a 3D-printed cap which rests on top of the device to prevent debris from falling inside. There is also a hole on top and an empty air chamber running alongside the cathode to facilitate consistent airflow. As for the lower end of cathode, it will remain embedded into the surface so to ensure that it stays hydrated from the moist surrounding soil. The hydration element stays intact even when the surface soil dries out in sunlight. Hold on, there is more. Researchers went one step further by coating part of the cathode with waterproofing material to let it breathe during a flood. If a flood does come, cathode’s vertical design will also help it to dry out gradually rather than all at once. In terms of concrete numbers, the winning fuel generated, on an average, 68 times more power than needed to operate its sensors. It even turned out to be robust enough to withstand large changes in soil moisture—from somewhat dry (41% water by volume) to completely underwater.

“The number of devices in the Internet of Things (IoT) is constantly growing,” said Yen. “If we imagine a future with trillions of these devices, we cannot build every one of them out of lithium, heavy metals and toxins that are dangerous to the environment. We need to find alternatives that can provide low amounts of energy to power a decentralized network of devices. In a search for solutions, we looked to soil microbial fuel cells,”

With that entire technological prowess covered, the only detail which can enhance the stature of this development is its accessibility, meaning you can purchase all ingredients for the new soil-based MFC from a local hardware store. For the future, though, the team plans on developing a soil-based MFC made from fully biodegradable materials. Not just that, the intention is also to avoid using complicated supply chains and conflict minerals in the development process.

“With the COVID-19 pandemic, we all became familiar with how a crisis can disrupt the global supply chain for electronics,” said Josiah Hester, co-author on the study and a former Northwestern faculty member. “We want to build devices that use local supply chains and low-cost materials so that computing is accessible for all communities.”