Bio fuel cell

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A bio-fuel cell converts the chemical reaction energy of a continuously supplied fuel and an oxidizing agent into electrical energy . In contrast to conventional fuel cells , bio-fuels are biological energy sources.

Fuel cell types

Microbial fuel cells

Function of a glucose-powered fuel cell

In microbial fuel cells ( MBZ ), living microorganisms that process organic substances as part of their energy metabolism are used directly to generate energy. The electrons generated during metabolism are transferred by these microorganisms to an electrode and thus enable electricity to be generated. The microorganisms fulfill the function of a biocatalyst in the MBZ . Microbial fuel cells are used to generate energy from wastewater and waste, but the current densities currently achievable do not yet allow economically sensible use on a larger scale.

Blood sugar fuel cell

The electrochemical conversion of the body's own blood sugar can generate energy that can be used, for example, to supply medical implants . Such a fuel cell works on the same principle as the energy generation of living cells. Glucose is enzymatically oxidized at the negative pole and the hydrogen obtained is split into electrons and protons . The electrons flow through an external conductor via a consumer to the positive pole, and the protons diffuse through a separator. At the positive pole, the electrons and protons react with atmospheric oxygen to form water again with the help of enzymes. This would make changing the battery superfluous, especially for long-term implants.

Enzymatic fuel cell

An enzymatic fuel cell is a special type of bio fuel cell that uses enzymes as a catalyst for the oxidation of the fuel. The enzymes therefore represent an alternative to expensive catalyst metals.

The enzymes offer various advantages over conventional catalysts. In this way, the enzymes can be produced in large numbers in a comparatively simple manner and therefore have a significantly better availability than, for example, standard platinum catalysts .

In addition, enzymes work well with organic fuels such as sugar and alcohol, so that not only cheap fuels can be used, but also applications in the field of medical technology , e.g. B. for implants come into question. Disadvantages compared to catalyst metals are that enzymes have a significantly shorter shelf life and they are more susceptible to aggressive reaction conditions.

Applications

At present (as of 2012) there is still no commercial application of bio fuel cells. As can be seen from current research projects, z. B. the following applications are conceivable:

  • Energy harvesting - e.g. B. for battery-independent power supply of implants with a blood sugar fuel cell
  • Use of biogenic residues, e.g. B. in wastewater, cf. Microbial fuel cell .

See also

Web links

Individual evidence

  1. Bruce E. Logan: Microbial Fuel Cells. John Wiley & Sons; Edition: 1st edition, February 2008, ISBN 978-0470239483 .
  2. S. Candle maker: Glucose fuel cells as self-sufficient energy supply for medical micro-implants: state of the art and current developments. In: Proceedings MikroSystemTechnik Dresden , 10/2007.
  3. G. Tayhas: Microbial and Enzymatic Biofuel Cells In: ME Himmel: Enzymatic Conversion of Biomass for Fuels Production (= Chapter 14) American Chemical Society, 1994, ISBN 9780841229563
  4. Project description at the University of Freiburg: "Graduate College" Micro Energy Harvesting "- Implantable Direct Glucose Fuel Cells". Retrieved July 18, 2012 .
  5. Batteries that live on waste. BIOPRO Baden-Württemberg GmbH, January 10, 2011, accessed on July 18, 2012 .