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in publisher: "Duke Univ., Durham, NC United States. Dept. of Mechanical Engineering and Materials Science"  
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Novel carbon-ion fuel cells. Quarterly technical report No. 10, January 1, 1996--March 31, 1996

Description: This report presents research to develop an entirely new, fundamentally different class of fuel cell using a solid electrolyte that transports carbon ions. This fuel cell would use solid carbon dissolved in molten metal as a fuel reservoir and anode; expensive gaseous or liquid fuel would not be required. A high temperature fuel cell based on a carbon ion membrane/electrolyte would operate in a way like yttria-doped zirconia solid oxide fuel cells; however, the fuel cell would transport the C ion from a fuel source to O{sub 2} in the atmosphere. Such fuel cells, operating above 1000 C, would produce an exhaust gas that could be fed directly into existing boilers, and could thus act as ``topping cycles`` to existing power plant steam cycles.
Date: August 1, 1996
Creator: Cocks, F.H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department

Novel carbon-ion fuel cells. Quarterly technical report, April--June 1996

Description: This report presents research to develop a new type of of fuel cell using a solid electrolyte that transports carbon ions. This new class of fuel cell would use solid C dissolved in molten metal (carbide) as a fuel reservoir and anode; thus expensive gas or liquid fuel would not be required. Thermodynamic efficiency of carbon-ion fuel cells is reviewed, as are electrolyte crystal structures (oxide and fluorite carbides). The sequence of laboratory research procedures for developing a solid C-ion electrolyte and to determine the ionic conductivity of C ions therein is outlined; results of the laboratory research to date are summarized, including XRD analysis of crystal structures and transition temperatures of carbides (La, Ce, Be, Al) and SIMS of carbon isotopes.
Date: November 1, 1996
Creator: Cocks, F.H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department

Novel carbon-ion fuel cells. Final report, October 1, 1993--September 30, 1996

Description: Mixed lanthanide dicarbides having the fluorite crystal structure have been synthesized using the elemental lanthanide metals and elemental carbon that was 99.9% pure carbon-13 isotope. A two step process of first, arc furnace melting of the components, followed by an annealing step in a high vacuum furnace, was adopted as the standard method of fabricating small cast ingots of the dicarbides. The crystal structure of the various lanthanide dicarbides produced were confirmed by x-ray diffraction under protective atmospheres at both room temperature at Duke University and at high temperature at Oak Ridge National Laboratory. After more than 15 combinations of cerium or lanthanum with dopants were tried, low temperature x-ray diffraction showed that Ce{sub .5}Er{sub .5}C{sub 2} had been successfully stabilized and had the desired fluorite crystal structure at room temperature. The fluorite crystal structure lanthanide dicarbide cast ingots were further prepared by having flat and clean surfaces ground onto their surfaces by high-speed milling machines inside argon gas atmosphere gloveboxes. The surfaces thus created were then coated with carbon-12 by the arc evaporation method under low pressure argon gas. The coated ingots were then allowed to have carbon diffusion occur from the surface coating of carbon-12 into the ingot of dicarbide that had been synthesized from carbon-13. After the diffusion run, the cast ingots were slit down the axis perpendicular to the carbon coating. The fracture surface created was then squared and polished by high,speed milling in a glove box with a argon atmosphere. The high diffusion co-efficient of carbon in lanthanide dicarbides having the fluorite crystal structure would make possible the manufacture of a carbon-ion electrolyte for use in a battery or a fuel cell that could consume solid carbon as it`s feedstock.
Date: January 1, 1997
Creator: Cocks, F.H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department

Novel carbon-ion fuel cells. Quarterly technical report No. 9, October 1, 1995--December 31, 1995

Description: This report presents research to develop an entirely new, fundamentally different class of fuel cell using a solid electrolyte that transports carbon ions. This fuel cell would use solid carbon dissolved in molten metal as a fuel reservoir and anode; expensive gaseous or liquid fuel would not be required. Thermodynamic factors favor a carbon-ion fuel cell over other fuel cell designs: a combination of enthalpy, entropy, and Gibbs free energy makes the reaction of solid carbon and oxygen very efficient, and the entropy change allows this efficiency to slightly increase at high temperatures. The high temperature exhaust of the fuel cell would make it useful as a ``topping cycle``, to be followed by conventional steam turbine systems.
Date: December 31, 1995
Creator: Cocks, F.H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department

Novel carbon-ion fuel cells. First quarter 1995 technical progress report

Description: Research continued on task 2, the measurements on carbides with the fluorite structure. There are twelve known carbides of the fluorite structure with transition temperatures from 350-1450 C. Small quantities of these carbides in powder form will be purchased when commercially available. Pellets pressed from powder within an inert atmosphere will be made, CVI treated, and tested as described in Task No. 1. Pure carbides will be tested first, followed by carbides doped with impurities of different electrical valences whose atomic radii are favorable for solubility in the carbide lattice structure. Dopants will be introduced either during the chemical formation of the carbide, by mix and sinter diffusion, or by high energy ion bombardment of the powder prior to pelletization. The approximate time period for completion of Task No. 2 is twelve months. Investigations have been hampered by equipment failures. Progress is described.
Date: April 18, 1994
Creator: Cocks, F. H. & LaViers, H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department