A Mitochondrion-Inspired Magnesium-Oxygen Biobattery with High Energy Density In Vivo

Implantable batteries are urgently needed as a power source to meet the demands of the next generation of biomedical electronic devices. However, existing implantable batteries suffer from unsatisfactory energy density, hindering the miniaturization of these devices. Here, a mitochondrion-inspired magnesium-oxygen biobattery that achieves both high energy density and biocompatibility in vivo is reported. The resulting biobattery exhibits a recorded energy density of 2517 Wh L-1/1491 Wh kg-1 based on the total volume/mass of the device in vivo, which is approximate to 2.5 times higher than the current state-of-the-art, and can adapt to different environments for stable discharges. The volume of the magnesium-oxygen biobattery can be as thin as 0.015 mm3 and can be scaled up to 400 times larger without reducing the energy density. Additionally, it shows a stable biobattery/tissue interface, significantly reducing foreign body reactions. This work presents an effective strategy for the development of high-performance implantable batteries. A novel magnesium-oxygen biobattery with a double-membrane structure, inspired by the mitochondrion, is presented. The biobattery exhibits an unprecedented volumetric energy density of 2517 Wh L-1 based on the overall volume of the device in vivo. It also shows excellent biocompatibility, with high device/tissue affinity.image