World's smallest fuel cell

Because the device is so small - just 3 mm by 3 mm by 1 mm - surface tension, not gravity, controls the flow of water through the system. This means that the cell operates even if moved and rotated - perfect for life inside a pocket gadget.

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a Biological Fuel Cell

Biological fuel cells use enzymes or whole microorganisms as biocatalysts for the direct conversion of chemical energy to electrical energy. One type of microbial fuel cell uses anodes (positive electrodes) coated with a bacterial film. The fuel consists of a substrate that the bacteria can break down. The electrons released in this process must be transferred to the anode in order to be drawn off as current. But how can the electrons be efficiently conducted from the microbial metabolism that occurs inside a cell to the anode?

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