An anonymous reader quotes a report from Ars Technica: A team of researchers at the Italian Institute of Technology (IIT) in Milan recently created a fully rechargeable battery using nontoxic edible components. This is probably the world’s first battery that is safe to ingest and entirely made of food-grade materials. “Given the level of safety of these batteries, they could be used in children’s toys, where there is a high risk of ingestion,” said Mario Caironi, a senior researcher at IIT. However, this isn’t the only solution the edible battery could provide. Apart from serving as an alternative to conventional toxic toy batteries, the edible battery from IIT could also play a key role in making health care applications safer than ever. For instance, doctors have to be cautious regarding the use of miniature electronic devices (such as drug-delivery robots, biosensors, etc.) inside the human body, as they come equipped with batteries made of toxic substances. An edible battery could solve this problem. There are also more mundane applications, like replacing batteries in pet toys.

Ivan K. Ilic, first author of the study and a postdoctoral researcher at IIT, told Ars Technica, “Two main ways a battery damages human tissue when it’s inside the body is by doing water electrolysis and by the toxicity of its materials. Water electrolysis is a phenomenon where electricity with a voltage higher than 1.2 V (virtually all commercial batteries) breaks water into oxygen and hydrogen (an explosive gas), and it is very dangerous if it occurs in the stomach. Our battery is way below this voltage, around 0.65 V, so water electrolysis cannot occur. On the other hand, we used only food materials, so nothing is toxic!” Before the battery is useful, however, the researchers will need to first enhance the battery’s power capacity. Currently, the edible battery can supply 48 microamperes of current for a bit over 10 minutes. So it can easily meet the power demand of a miniature medical device or a small LED. “These batteries are no competition to ordinary batteries — they will not power electric cars — but they are meant to power edible electronics and maybe some other niche applications, so their main advantage is non-toxicity,” said Ilic. Here’s a list of what makes these edible batteries work, as mentioned by Ars:

– “Quercetin, a pigment found in almonds and capers, serves as the battery cathode, whereas riboflavin (vitamin B2) makes up the battery anode.
– The researchers used nori (edible seaweed that is used in the wrapping of sushi rolls) as the separator and a water-based solution (aqueous NaHSO4) as the electrolyte.
– Activated charcoal is employed to achieve high electrical conductivity in the battery.
The battery electrodes come covered in beeswax and connect to a gold foil (used to cover pastries) that laminates a supporting structure made of ethyl cellulose.”

The research has been published in the journal Advanced Materials.

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