Scientists Create A Fully Rechargeable Battery, Made Entirely From Food

Scientists are continuing to make advances in electronics that can safely monitor and treat our health from inside the body. Unfortunately, powering these miniature medical gadgets isn't always straightforward.

There's now a new type of rechargeable battery that could help in that department. Made from fully edible substances, it can dissolve safely in the stomach once it's done whatever it needs to do.

The prototype device outlined in a new study operates at a harmless 0.65 volts and provides a current of 48 microamperes for 12 minutes – within the range needed to give tiny electronics a power supply.

"Future potential uses range from edible circuits and sensors that can monitor health conditions to the powering of sensors for monitoring food storage conditions," says senior author Mario Caironi, a molecular electronics researcher at the Italian Institute of Technology.

"Moreover, given the level of safety of these batteries, they could be used in children's toys, where there is a high risk of ingestion."

Built from a varied list of ingredients, it's the first functional rechargeable battery that can be served as a snack. Its components include the vitamin riboflavin for the battery's anode (its 'negative' end), and the supplement quercetin as the cathode (the 'positive' end). The electrolyte (which generates the electrical charge) is made from a water-based solution, and the separator (which prevents short circuits) is made from nori, the seaweed you find at sushi restaurants.

The prototype in action. (Ilic et al., Advanced Materials, 2023)

Activated charcoal, often used to treat poisonings, is included to increase electrical conductivity, while the external contacts that transfer the electricity to another device are fashioned out of beeswax, connected to food-grade decorative gold.

Ok, nobody said it was a meal worthy of a Michelin star. But what it lacks in flavor it makes up for in potential.

The battery maintains its charge well over dozens of cycles, though it needs to be outside the body to be recharged. The prototype created here is around a square centimeter (0.155 square inches) in size, but the team is already working on making it smaller.

"Actually, we are already developing devices with greater capacity and reducing the overall size," says Caironi. "These developments will be tested in future also for powering edible soft robots."

If you've ever had a camera or other device threaded inside you, you'll know that these scans – while hugely important in detecting disease – aren't the most comfortable experiences. This is one area where this edible battery could help.

Another is in the field of food quality monitoring: devices could be used to check that foodstuffs were safe and up to the standards required while they're actually in the gut, before the monitoring device is digested along with the food.

All this is still some way off, but the researchers behind the prototype are hoping that their work leads to further developments in the field, with larger batteries used for energy storage and electric cars, for example.

"While our edible batteries won't power electric cars, they are proof that batteries can be made from safer materials than current Li-ion batteries," says one of the study's coauthors, Ivan Ilic, a sustainable energy storage scientist from the Italian Institute of Technology.

"We believe they will inspire other scientists to build safer batteries for a truly sustainable future."

The research has been published in Advanced Materials.

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