Artificial leaf can produce 40 volts of electricity from wind or rain

This process of harvesting energy from rain is new.

Loukia Papadopoulos
Created: Mar 18, 2023

Plants covered in rain.

Researchers in Italy have engineered an artificial leaf that can be embedded within plants to create electricity from raindrops or wind.

It functions extremely well under rainy or windy conditions to light up LED lights and power itself, according to a report by IEEE Spectrum published on Wednesday.

Fabian Meder, a researcher studying bioinspired soft robotics at the Italian Institute of Technology (IIT) in Genoa, Italy, told the science news outlet that the system could be practical for agricultural applications and remote environmental monitoring in order to observe plant health or monitor climate conditions.

In order for the device to work, it is added to the leaves of a real plant.

“When the [leaves] move in the wind, the two surfaces touch each other and separate again, creating static charges on the plant leaf cuticle and on our device,” told IEEE Spectrum Meder.

“These charges are induced into the inner cellular tissue of the plant, where they create a current. We can harvest this current by an electrode inserted into the plant tissue.”
Harvesting energy from rain

We have witnessed artificial leaves that use a similar technique to create electricity from wind, but the process of harvesting energy from raindrops is new.

The researchers proceeded to embed their artificial leaf system within the leaves of a living oleander plant, and evaluate its ability to produce energy.

The results indicated that single water drops could create voltage and current peaks of over 40 volts and 15 microamperes and can power 11 LED lights.

“The results revealed that wind and rain energy harvesting are possible with the device—either separately or simultaneously—making it a multifunctional energy harvester or self-powered sensor,” told IEEE Spectrum Barbara Mazzolai, associate director for robotics and director of the IIT’s Bioinspired Soft Robotics Laboratory, who also took part in the study.

She further explained that the main advantage of this energy-harvesting system compared to other similar models is that it can actually create more electricity in wet conditions. Other artificial leaves are bogged down when wet.

Now, the researchers are working on improving the performance of their artificial leaf through design modifications such as the shapes of the electrodes and the materials chosen.

“We have filed a patent application on the technology and are analyzing the potential markets,” concluded Mazzolai. “Still, some research is necessary before defining the final product—for example, we want to test the systems in detail under outdoor and strongly varying wind and rain conditions.”

The study is published in the journal IEEE Robotics and Automation Letters.

Study abstract:

Soft (bio)hybrid robotics aims at interfacing living beings with artificial technology. It was recently demonstrated that plant leaves coupled with artificial leaves of selected materials and tailored mechanics can convert wind-driven leaf fluttering into electricity. Here, we significantly advance this technology by establishing the additional opportunity to convert kinetic energy from raindrops hitting the upper surface of the artificial leaf into electricity. To achieve this, we integrated an extra electrification layer and exposed electrodes on the free upper surface of the wind energy harvesting leaf that allow to produce a significant current when droplets land and spread on the device. Single water drops create voltage and current peaks of over 40V and 15µA and can directly power 11 LEDs. The same structure has the additional capability to harvest wind energy using leaf oscillations. This shows that environment-responsive biohybrid technologies can be tailored to produce electricity in challenging settings, such as on plants under motion and exposed to rain. The devices have the potential for multisource energy harvesting and as self-powered sensors for environmental monitoring, pointing at applications in wireless sensor networks (WSNs), the Internet of Things (IoT), smart agriculture, and smart forestry.