Figure 1: Schematic view of a bio-nanobattery formed from ferritin containing a Fe(OH)2 mineral core connected to a ferritin containing a Co(OH)3 mineral core. The cutout view shows the mineral cores within each ferritin type. The ferritin battery components are immersed in buffer, which is typically 0.05 M pH 7.0–9.0 containing 0.10 M NaCl.