An Edible Supercapacitor Based on Zwitterionic Soy Sauce‐Based Gel Electrolyte

Abstract With rapid technological developments, the use and reliance on small and miniaturized electronics have increased significantly. Prevalent power sources used in wearable and implantable devices are based on potentially toxic materials. This creates massive environmental problems and generates waste that requires novel and sustainable solutions in the Internet of Things era. Alongside newly developed biodegradable and implantable devices, edible and ingestible electronic devices have emerged to create a niche and sustainable solution. To realize these devices, energy sources must also be edible and ingestible. Here, zwitterionic and edible gel electrolytes are produced using hydroxyethyl cellulose and commercial soy sauce (shoyu) for superior ionic conductivity, providing a favorable environment for L929 proliferation. These edible gels are combined with carbon electrodes to fabricate edible supercapacitor devices, resulting in an ideal double‐layer capacitance. These gels have been discovered to operate at sub‐zero temperatures and possess anti‐drying properties. Introducing an edible soy sauce‐based gel with impressive ionic performance provides a promising alternative to conventional energy storage devices, enabling the advancement of cutting‐edge ingestible healthcare devices and environmentally friendly electronics.