Stackable, Storable, Millimeter-Scale Biobatteries Having High Instantaneous Power Outputs

We report a millimeter-sized bacteria-powered biobattery that can generate substantially high-power density (427 µW/cm
²
) only in 7 minutes after liquid introduction. The biobattery features (i) Bacillus subtilis endospores as a storable, dormant biocatalyst which are primed for quick germination, and (ii) a 3-D graphene hydrogel anode decorated with copper oxide particles for high-power generation. Individual biobattery units are easily stackable in series and three-biobattery pack produces more than enough energy to power a light-emitting diode (LED). This work can release microbial energy technology from its restriction to research settings and translate it to practical real-world applications.