A Coplanar Edible Rechargeable Battery with Increased Capacity and Durability

Edible electronics is an emerging research field focused on developing safe-to-ingest devices entirely made of food and food additives. Being intrinsically non-toxic and biodegradable, this technology can find applications in many scenarios, from healthcare to agrifood. Starting from common food additives like activated carbon, edible gold, ethyl cellulose, and beeswax, we developed the first edible rechargeable battery entirely made of food materials. The chemistry is based on two small redox-active molecules found in food, riboflavin, and quercetin, used as the anode and the cathode, respectively.^[1]<br/>Here we present a coplanar edible battery, characterized by an electrode configuration that eases compatibility and integration with electronic components. The battery provides an open-circuit voltage of ~0.65 V with a specific capacity of 20 µAh cm^-2, a two-fold increment with respect to our first prototype, thanks to increased electrode mass loading. The beeswax encapsulation yields excellent operational stability, characterized over a two-week period and in different environmental conditions. As proof of the compatibility with traditional electronic devices, the battery was successfully used to power up resistive sensors, including thermistors and photoresistors. Multiple batteries were also employed to supply power to an Internet of Things module which can acquire humidity and temperature information and transmit data in real-time via Bluetooth.<br/>The high degree of versatility of our technology goes beyond the proposed proof-of-concept: we envision edible batteries as a promising alternative to traditional ones in low-power applications, such as agrifood sensor networks and food monitoring. <br/> <br/>[1] Ilic, I. K., Galli, V., Lamanna, L., Cataldi, P., Pasquale, L., Annese, V. F., Athanassiou, A., & Caironi, M. (2023). An edible rechargeable battery. <i>Advanced Materials</i>, <i>35</i>(20), 2211400.