New reliable and renewable algae-powered battery to power IoT

A team of researchers from the University of Oxford, UK, managed to power a microprocessor for an entire year using only algae, light and water, according to a study published in the journal Energy & Environmental Science. The system is stationary and the authors believe it has the potential to be a power source to power small devices.

The system uses a non-toxic algae called Synechocystis which can harvest energy from the sun through photosynthesis. The electrical current generated can interact with an aluminum electrode, which is then used to power a microprocessor.

Because the system uses only common and inexpensive materials, it could be replicated thousands of times to power small devices as part of the Internet of Things. The Internet of Things – IoT – is a growing network of electronic devices with sensors, processing capability, software and other technologies to connect to other devices on the Internet – this includes, for example, cell phones, smart watches and even temperature sensors in power plants. Millions of these devices already exist, and the number is expected to reach one trillion by 2035, and many of them will need a portable power source. The authors suggest that this approach could be instrumental in off-grid or remote locations, where even small amounts of power could be of great benefit.

“The growth of the Internet of Things requires an increasing amount of energy, and we believe this will need to come from systems that can generate energy, rather than just store it like batteries,” said Professor Christopher Howe from the University of Cambridge’s Department of Biochemistry. main co-author of the article. “Our photosynthetic apparatus does not discharge like a battery, because it continually uses light as its energy source.”

In the study, the device powered an Arm Cortex M0+, a very common microprocessor in the Internet of Things. It operated in a domestic and semi-outdoor environment using natural light and was subject to temperature variations. It’s about the size of an AA battery and was built with common, inexpensive, and largely recyclable materials.

“We were impressed with how smoothly the system worked over a long period – we thought it might stop after a few weeks, but it kept going,” said Dr Paolo Bombelli from the University’s biochemistry department. of Cambridge, and first author of the paper.

Above all, algae do not need to feed because they can photosynthesize their own food. The device can even continue to work in the dark, even though the algae will stop photosynthesis. The researchers believe this is because the algae can continue to process their food when there is no light and continue to generate an electric current.

The authors believe this could be a serious alternative to lithium batteries. Powering trillions of devices with lithium batteries will be next to impossible: manufacturers would need three times as much lithium as is currently produced in the world. In addition, photovoltaic devices use hazardous materials with adverse effects on the environment, which means that they are not an option either.

Bombelli P, Savanth A, Scarampi A, Rowden S, Green D, Erbe A, Årstøl E, Jevremovic I, Hohmann-Marriott M, Trasatti S, Ozer E and Howe C (2022) Powering a microprocessor by photosynthesis. Energy and Environmental Sciences, https://doi.org/10.1039/D2EE00233G


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