A ground-breaking study at the IIT in Milan. Using common food substances, researchers have created a battery that 'produces' a weak electric current but can operate medical devices.
It might sound like science fiction, but a team of researchers at the Milan branch of the Italian Institute of Technology (IIT) has developed a completely edible, rechargeable battery using everyday food materials. According to scientists, this unique battery, described in an article published in the scientific journal Advanced Materials, could be used to diagnose and treat certain diseases of the gastrointestinal tract (inside mini devices that will then be digested), but also for monitoring food quality.
Edible batteries: how do they work?
Researchers were inspired by oxidation-reduction (or redox) reactions that take place in living beings: chemical reactions (in extremely simple terms) where there is a transfer of electrons from one chemical substance to another. Scientists thus developed a battery that uses riboflavin (vitamin B2 found, for example, in almonds,) as the anode and quercetin (found in capers and other vegetables) as the cathode (the anode is the negative pole of batteries, and the cathode is the positive).
Activated charcoal (a popular over-the-counter medicine) was used to increase the flow (current) of electrons, while the electrolyte (the liquid used to conduct the electricity produced) was water-based. Finally, the separator, which every battery needs to prevent short circuits, was made of nori seaweed, the kind found in sushi. The electrodes were then enclosed in beeswax from which two food-grade gold contacts (the film used by confectioners for decorations) protruded on a cellulose-derived base.
A weak but adequate current
The battery operates at 0.65 volts, low enough not to cause problems to the human body if swallowed, and it can provide a (very weak) current of 48 microamperes (millionths of an ampere) for 12 minutes, or a few microamperes for more than an hour, enough, however, to power small electronic devices like low-power LEDs.
The IIT claims that this edible, rechargeable battery – the first of its kind – paves the way for new applications in edible electronics, which is a rapidly growing sector. According to researchers, as well as monitoring the health and storage conditions of food, these batteries could also be used in the future, given their good safety record, for certain types of children’s toys (especially those with a higher risk of being swallowed).
No toxic substances
The Milanese team is working on developing edible batteries with a greater output, while keeping their compact size, that could also power soft edible robots. But, perhaps, what is most important is they have shown that making batteries without toxic (and rare) materials is possible, and even affordable.
The project was awarded a 2 million Euro ERC Grant – funding intended for the most innovative research – from the European Union.