Nuclear resonance investigtion of hydrogen mobility in chromous acid (. cap alpha. -HCrO/sub 2/). [For possible use as hydrogen ion conducting solid electrolyte for fuel cell]

Journal Article · Fri Apr 01 04:00:00 EST 1977 · Mater. Res. Bull.; (United States)

DOI:https://doi.org/10.1016/0025-5408(77)90056-3· OSTI ID:7212394

Follstaedt, D M; Biefeld, R M; Ginley, D S

There is considerable interest in developing a hydrogen ion conducting solid electrolyte because solids with fast proton conduction could be of considerable utility as separators in fuel cells. Chromous acid (HCrO/sub 2/) was chosen as a possible hydrogen ion solid electrolyte because of the similarity of its structure to that of the well known solid electrolyte, Na ..beta..-alumina. The structure of ..cap alpha..-HCrO/sub 2/ consists of continuous sheets of (CrO/sub 6/)/sup -9/ octahedra. The oxygen ions of adjacent sheets are exactly superimposed and are connected by hydrogen ion bridges. The hydrogen ions form a continuous two-dimensional layer. In Na ..beta..-alumina, sheets of aluminum and oxygen ions are separated by layers of sodium and oxygen ions. Since the sodium ions are known to diffuse rapidly between the sheets of aluminum and oxygen ions it was thought that the hydrogen ions might also diffuse between the sheets of (CrO/sub 6/)/sup -9/ octahedra in HCrO/sub 2/. To search for evidence of H/sup +/ diffusion, NMR measurements of the proton relaxation times were done and were found to be temperature independent between 24 and 400/sup 0/C. The absence of motional narrowing requires H/sup +/ diffusion times to satisfy tau/sub jump/ greater than or equal to T/sub 2/ = 30 ..mu..sec at 400/sup 0/C. Thus ..cap alpha..-HCrO/sub 2/ does not appear promising as a hydrogen ion solid electrolyte. (WHK)

• Research Organization: Sandia Labs., Albuquerque, NM
• OSTI ID: 7212394
• Journal Information: Mater. Res. Bull.; (United States), Journal Name: Mater. Res. Bull.; (United States) Vol. 12:4; ISSN MRBUA
• Country of Publication: United States
• Language: English

Related Subjects

30 DIRECT ENERGY CONVERSION
300503* -- Fuel Cells-- Materials
Components
& Auxiliaries
CHALCOGENIDES
CHARGED PARTICLES
CHROMIUM COMPOUNDS
CHROMIUM OXIDES
DIFFUSION
DIRECT ENERGY CONVERTERS
ELECTROCHEMICAL CELLS
ELECTROLYTES
FUEL CELLS
HIGH-TEMPERATURE FUEL CELLS
HYDROGEN COMPOUNDS
HYDROGEN IONS
INORGANIC ACIDS
IONS
MAGNETIC RESONANCE
NUCLEAR MAGNETIC RESONANCE
OXIDES
OXYGEN COMPOUNDS
RELAXATION
RESONANCE
TEMPERATURE EFFECTS
TRANSITION ELEMENT COMPOUNDS