The proof-of-concept battery cell, which could lead to applications in health diagnostics, food quality monitoring and edible soft robotics, was developed at the Italian Institute of Technology (IIT) in Milan.
Inspired by the biochemical redox reactions that happen in all living beings, the research team used riboflavin (vitamin B2, found in foods including almonds) as the battery anode, and quercetin (a food supplement and ingredient found in capers and other foods) as the cathode. The separator, needed in every battery to avoid short circuits, was made from nori seaweed, which is used in sushi. The electrodes were encapsulated in beeswax, from which two food-grade gold contacts (sometimes used by pastry chefs) extend on a cellulose-derived support.
The battery cell operates at 0.65V, which the researchers said is low enough not to create problems in the human body when ingested. It can provide current of 48μA for 12 minutes, or a lower level for more than an hour, enough to supply power to small electronic devices such as low-power LEDs for a limited time.
The battery could open the door to new edible electronic applications, the IIT team said.
“Future potential uses range from edible circuits and sensors that can monitor health conditions, to the powering of sensors for monitoring food storage conditions,” said research coordinator Mario Caironi.
“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. Actually, we are already developing devices with greater capacity and reducing the overall size. These developments will be tested in future, also for powering edible soft robots.”
Co-author Ivan Ilic added: “This edible battery is also very interesting for [the] energy storage community. Building safer batteries, without usage of toxic materials, is a challenge we face as battery demand soars.
“While our edible batteries won’t power electric cars, they are a proof that batteries can be made from safer materials than current Li-ion batteries. We believe they will inspire other scientists to build safer batteries for [a] truly sustainable future.”
Biomedical devices using the battery could be used for diagnosis or treatment of gastrointestinal tract diseases.
Other projects that have emerged from the nascent edible electronics field include the edible drone from the Swiss Federal Institute of Technology in Lausanne (EPFL), which has wings made of rice cakes to provide potentially life-saving nutrition to people in emergency situations.
The IIT research was published in Advanced Materials.
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