Direct carbon fuel cell explained

A Direct Carbon Fuel Cell (DCFC) is a fuel cell that uses a carbon rich material as a fuel such as bio-mass^[1] or coal.^[2] The cell produces energy by combining carbon and oxygen, which releases carbon dioxide as a by-product.^[3] It is also called coal fuel cells (CFCs), carbon-air fuel cells (CAFCs), direct carbon/coal fuel cells (DCFCs), and DC-SOFC.

The total reaction of the cell is C + O₂ → CO₂. The process in half cell notation:

• Anode: C + 2O²⁻ → CO₂ + 4e⁻
• Cathode: O₂ + 4e⁻ → 2O²⁻

Despite this release of carbon dioxide, the direct carbon fuel cell is more environmentally friendly than traditional carbon burning techniques. Due to its higher efficiency, it requires less carbon to produce the same amount of energy. Also, because pure carbon dioxide is emitted, carbon capture techniques are much cheaper than for conventional power stations. Utilized carbon can be in the form of coal, coke, char, or a non-fossilized source of carbon.^{[4] [5] [6]} At least four types of DCFC exist.

Solid oxide fuel cell based design

Anode reactions:

Direct electrochemical oxidation path:

C + 2O²⁻ → CO₂ + 4e⁻

C + O²⁻ → CO+ 2e⁻

Indirect electrochemical oxidation path: CO + O²⁻ → CO₂ + 2e⁻

Boudouard reaction (indirect chemical reaction path): C + CO₂ → 2CO

Cathode reaction: O₂ + 4e⁻ → 2O²⁻

^[7]

Molten hydroxides fuel cell

William W. Jacques obtained US Patent 555,511 in this type of fuel cell in 1896. Prototypes have been demonstrated by the research group, SARA, Inc.

Molten carbonate fuel cell

William W. Jacques obtained a Canadian patent for the molten carbonate fuel cell in 1897^[8] It has been developed further at the Lawrence Livermore Laboratory.

Molten tin anode

This design utilizes molten tin and tin oxide as an inter stage reaction between oxidation of the carbon dissolving in the anode and reduction of oxygen at the solid oxide cathode.^{[9] [10]}

See also

• Glossary of fuel cell terms

External links

• CSIRO Energy
• ERTL, School of Environmental Science and Engineering, Gwangju Institute of Science and Technology
• CSIRO Advanced carbon power
• Direct Carbon Fuel Cells an ultra low emission technology for power generation
• Direct Carbon Fuel Cells, Alternative to a Hydrogen Economy?
• Direct Carbon Fuel Cell Workshop
• A closer look at Direct Carbon Fuel Cells: the ultimate biomass conversion technology?
• DCFC Paper, Enhanced anode interface for electrochemical oxidation of solid fuel in direct carbon fuel cells: The role of liquid Sn in mixed state
• Science and Technology Review

Notes and References

1. Munnings. C.. Kulkarni. A.. Giddey. S.. Badwal. S.P.S.. Biomass to power conversion in a direct carbon fuel cell. International Journal of Hydrogen Energy. August 2014. 39. 23. 12377–12385. 10.1016/j.ijhydene.2014.03.255.
2. Rady. Adam C.. Giddey. Sarbjit. Kulkarni. Aniruddha. Badwal. Sukhvinder P.S.. Bhattacharya. Sankar. Degradation Mechanism in a Direct Carbon Fuel Cell Operated with Demineralised Brown Coal. Electrochimica Acta. October 2014. 143. 278–290. 10.1016/j.electacta.2014.07.088.
3. Giddey. S . Badwal SPS . Kulkarni A . Munnings C. A comprehensive review of direct carbon fuel cell technology. Progress in Energy and Combustion Science. 2012. 38. 3. 360–399. 10.1016/j.pecs.2012.01.003.
4. Rady. Adam C.. Giddey. Sarbjit. Kulkarni. Aniruddha. Badwal. Sukhvinder P.S.. Bhattacharya. Sankar. Degradation Mechanism in a Direct Carbon Fuel Cell Operated with Demineralised Brown Coal. Electrochimica Acta. October 2014. 143. 278–290. 10.1016/j.electacta.2014.07.088.
5. Munnings. C.. Kulkarni. A.. Giddey. S.. Badwal. S.P.S.. Biomass to power conversion in a direct carbon fuel cell. International Journal of Hydrogen Energy. August 2014. 39. 23. 12377–12385. 10.1016/j.ijhydene.2014.03.255.
6. HyungKuk Ju, Jiyoung Eom, Jae Kwang Lee, Hokyung Choi, Tak-Hyoung Lim, Rak-Hyun Song, and Jaeyoung Lee, Durable power performance of a direct ash-free coal fuel cell, Electrochimica Acta 115 (2014) 511.
7. A Kulkarni . FT Ciacchi . S Giddey . C Munnings . SPS Badwal . JA Kimpton . D Fini . Mixed ionic electronic conducting perovskite anode for direct carbon fuel cells. International Journal of Hydrogen Energy. 2012. 37. 24. 19092–19102. 10.1016/j.ijhydene.2012.09.141.
8. Web site: CIPO - Patent - 55129 . 2008-09-13 . https://web.archive.org/web/20081029011254/http://patents.ic.gc.ca/cipo/cpd/en/patent/55129/summary.html . 2008-10-29 . dead .
9. Web site: http://www.celltechpower.com/technology.htm . February 18, 2009 . dead . https://web.archive.org/web/20090302040721/http://celltechpower.com/technology.htm . March 2, 2009 .
10. HyungKuk Ju, Sunghyun Uhm, Jin Won Kim, Rak-Hyun Song, Hokyung Choi, Si-Hyun Lee, Jaeyoung Lee, Enhanced anode interface for electrochemical oxidation of solid fuel in direct carbon fuel cells: The role of liquid Sn in mixed state, Journal of Power Sources 198 (2012) 36.