An Edible and Nutritive Zinc-Ion Micro-supercapacitor in the Stomach with Ultrahigh Energy Density

Miniature energy storage devices simultaneously combining high energy output and bioavailability could greatly promote the practicability of green, safe, and nontoxic in vivo detection, such as for noninvasive monitoring or treatment in the gastrointestinal tract, which is still challenging. Herein, we report ingestible and nutritive zinc-ion-based hybrid micro-supercapacitors (ZMSCs) consisting of an edible active carbon microcathode and zinc microanode, which can be inserted into a standard-sized capsule and ingested in a pig stomach. With features including flexibility, light weight, and shape adaptability, a single microdevice displays a high energy density of 215.1 μWh cm^-2, superior to that of state-of-the-art biocompatible SCs/MSCs and even traditional ZMSCs reported previously. It also delivers an areal capacitance of 605 mF cm^-2 and a high working voltage of 1.8 V, exceeding that of miniaturized commercial button batteries (1.55 V, RENATA 337). Comprehensive studies in vivo and in vitro demonstrate that the ZMSCs with high biocompatibility and safety not only power electronic equipment in the porcine stomach without a voltage booster but also act as a nutritional supplement of trace element zinc within the dose range, as well as the ability of potent antibacterial activity against bacterium Escherichia coli during the discharging process. This work provides an example for the design and fabrication of edible energy storage devices with high performance.