Accession Number : ADA430084


Title :   Solid Acid Based Fuel Cells


Descriptive Note : Final technical rept. Dec 2001-Sep 2004


Corporate Author : CALIFORNIA INST OF TECH PASADENA


Personal Author(s) : Haile, Sossina M.


Full Text : http://www.dtic.mil/get-tr-doc/pdf?AD=ADA430084


Report Date : 28 JAN 2005


Pagination or Media Count : 18


Abstract : High power density fuel cells based on solid acid electrolytes have been demonstrated. In particular, a fuel cell with a 25 micron thick CsH2PO4 membrane was fabricated and yielded a power density of 425 mW/cm2 at 26O C (H2/O2) without pressurization. In this configuration, the thin-film fuel cell is supported on a porous stainless steel gas diffusion layer and the electrocatalyst and electrolyte layers are spray-deposited. In parallel with these efforts, new, water-insoluble electrolytes have been developed. In particular, the new series of compounds Ba3-xKxHx(PO4)2 were prepared and shown to have conductivities of 3 x 10^-5 S/cm at 250 C. Although not as high as the conductivity of CsH2PO4, this result demonstrates the feasibility of obtaining proton transport via dynamic oxyanion reorientation in insoluble compounds. In addition, we have shown that it is possible to exchange out the Li in silicate salts such as LiLa9(SiO4)6O2, using a relatively weak acid (e.g. H3PO4) to once again produce proton conducting water insoluble compounds.


Descriptors :   *POWER LEVELS , *FUEL CELLS , *ACIDS , *SOLID ELECTROLYTES , HIGH POWER , THIN FILMS , STAINLESS STEEL , PROTONS , ELECTRICAL CONDUCTIVITY , DIFFUSION , PRESSURIZATION , SPRAYS , ELECTROCATALYSTS , POROUS METALS.


Subject Categories : ELECTROCHEMICAL ENERGY STORAGE
      INORGANIC CHEMISTRY
      PHYSICAL CHEMISTRY


Distribution Statement : APPROVED FOR PUBLIC RELEASE