A team of Italian scientists has built the first-ever entirely edible rechargeable battery, which could be used to power edible electronics.
If the device is eventually approved for manufacturing, it would have several applications in the healthcare, pharmacology and food science arenas. It could also play a key role in replacing current toxic battery technologies.
Mario Caironi, a scientist from the Center for Nano Science and Technology of Istituto Italiano di Tecnologia who coordinated the project, told The Jerusalem Post that the battery is made entirely from food-grade materials – an upgrade from its ingestible counterparts. He said the team took its inspiration from nature.
"The battery is made only from non-toxic and edible materials. All of its materials are either derived from food or considered food or food additives. Therefore, the final device is edible. But, of course, that does not mean it is meant to be eaten per se."
Mario Caironi
“The battery is made only from non-toxic and edible materials,” Caironi said. “All of its materials are either derived from food or considered food or food additives. Therefore, the final device is edible. But, of course, that does not mean it is meant to be eaten per se.”
The team used a 24-karat gold leaf, like the kind used to garnish fancy cakes, supported by the food additive ethyl cellulose, to create the conductor. The active materials on the positive and negative plates include riboflavin – known commonly as vitamin B2 – and quercetin, sold as a food supplement, and commonly found in capers. To create voltage, these two molecules are mixed with active carbon – widely used to make bread black or in medications to remove gases from the stomach. The battery separator is made of nori algae, the seaweed used to make sushi. The final current is conducted with the help of a water-based electrolyte and the casing is composed of beeswax.
“The goal was to find two edible molecules that could be charged and discharged like a battery,” Caironi explained. “We needed these molecules to have substantial voltage output, the ability to charge and discharge, be fully edible and easily found in what we eat to keep the price down. These criteria reduced the number of [possible] molecules substantially. Eventually, we tested a set of molecules until we found this couple.”
Caironi said the battery demonstrated stable operating potential compared to previously reported edible, non-chargeable batteries. He also noted that the battery’s voltage is safe – around 0.6 to 0.7. Anything under one volt can be ingested and will not produce any adverse reaction.
The new field of edible electronics
“The goal was to find two edible molecules that could be charged and discharged like a battery,” Caironi explained. “We needed these molecules to have substantial voltage output, the ability to charge and discharge, be fully edible and easily found in what we eat to keep the price down. These criteria reduced the number of [possible] molecules substantially. Eventually, we tested a set of molecules until we found this couple.”
Caironi said the battery demonstrated stable operating potential compared to previously reported edible, non-chargeable batteries. He also noted that the battery’s voltage is safe – around 0.6 to 0.7. Anything under one volt can be ingested and will not produce any adverse reaction.
The field of edible electronics is new, but Caironi and other researchers outside of Italy have already produced several prototypes, including transistors and sensors. However, this battery is the first entirely edible one.
In this case, the battery would not be meant to be swallowed with the food. However, if it did come in contact with the food, it would not cause any harm.
At the same time, the battery is more sustainable than current toxic ones. For example, the active components could be made using food waste, which would preserve the precious minerals like lithium currently used for batteries and have a less negative environmental impact.
Caironi cautioned that the device is only a prototype developed in a lab environment, so it cannot be moved to market yet. Instead, his team must now work on improved design to increase the capacity, and on best practices for mass manufacturing such a device and answering several safety and reliability questions.
The scientist said they would work on a proof of concept for a smaller battery version in the coming months and complete the other steps needed to take the battery out of the lab and into the market.