Sargassum Nanocellulose‐Based Fully Ingestible Supercapacitor

Abstract Small high‐performance energy modules have significant practical value in the biomedical field, such as painless diagnosis, alleviation of gastrointestinal discomfort, and electrical stimulation therapy. However, due to performance limitations and safety concerns, it is a formidable challenge to design a small, emerging ingestible power supply. Here, a fully ingestible supercapacitor (FISC) constructed of sargassum cellulose nanofiber is presented. FISCs exhibit an electrode areal capacitance of 2.29 F cm −2 and a high energy density of 307 µWh cm −2 . Furthermore, over 90% of the antibacterial activity against Escherichia coli is achieved during the self‐discharge process. Therefore, following insertion into an enteric capsule, this device can enable a disposable power supply and electrostimulation for bacteriostasis in the intestine after being swallowed by a human, which offers new possibilities for scientific and simple therapy.