Description: The Naval Research Laboratory (NRL) has developed a novel microbial fuel cell (MFC) for harvesting energy from aerobic aqueous environments. It is powered by passive nutrient diffusion instead of energy-draining pumps used in other MFCs, thereby increasing the net energy output. The NRL design sequesters electrochemically active microbes in the cell, rather than relying on environmentally available bacteria. This allows the NRL MFC to be placed in a wide range of aerobic aqueous environments, not only in the bacteria's natural habitat at the sediment/water interface. Unlike other MFCs, which require relatively costly proton exchange membranes to maintain separation between protons and electrons, the NRL MFC uses inexpensive nanoporous membranes made from polycarbonate or other materials to confine the microbes. The resulting MFC designs are capable of generating microwatts to milliwatts, depending upon size (75 ┬ÁL to 5 mL) and operating conditions (cathode catalyst, nutrients available, etc.). Many of the designs can be connected easily in series or in parallel for additional power generation. With the addition of a booster circuit, these MFCs can be used as a long term power supply for underwater autonomous sensors and LEDs.

Advantages/Features Include:

  • Operates via passive nutrient diffusion; no active pump required
  • Uses low-cost membranes compared to other MFCs
  • Capable of operation in a wide range of aerobic aqueous environments compared to other MFCs
  • High power density: up to 0.5 mW/cm3/cell
  • With booster circuit, long term power supply for autonomous sensors and LEDs

Applications:

  • Environmental Sensors
  • Waste water treatment and purification
  • Biore,ediation and waste reduction
  • Renewable electricity from biomass

References:

  • "Diversifying Biological Fuel Cell Designs by Use of Nanoporous Filters," Environmental Science and Technology 41 (2007) 1444-1449.
  • "High power density from a miniature microbial fuel cell using Shewanella oneidensis DSP10," Environmental Science and Technology 40 (8): 2629-2634 (2006).
  • "A Biofilm Enhanced Miniature Microbial Fuel Cell Using Shewanella oneidensis DSP10 and Oxygen Reduction Cathodes," Biosensors and Bioelectronics 22 (2007) 1672-1679.

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