Sökning: "PEROVSKITES"

Visar resultat 1 - 5 av 42 avhandlingar innehållade ordet PEROVSKITES.

1. 1. Vibrational proton dynamics in hydrated perovskites and alkali thio-hydroxogermanates

   Författare :Maths Karlsson; Chalmers University of Technology; []
   Nyckelord :fuel cell; proton conduction; perovskites; proton dynamics; thio-hydroxogermanates; vibrational spectroscopy;

   Sammanfattning : .... LÄS MER

3. 2. Solid state proton conductors: hydrated perovskites and hydrated alkali thio-hydroxogermanates

   Författare :Maths Karlsson; Chalmers University of Technology; []
   Nyckelord :NATURVETENSKAP; TEKNIK OCH TEKNOLOGIER; NATURAL SCIENCES; ENGINEERING AND TECHNOLOGY; neutron scattering; vibrational spectroscopy; alkali thio-hydroxogermanates; Proton conductors; fuel cells.; perovskites;

   Sammanfattning : This thesis concerns experimental studies of hydrated perovskites and hydrated alkali thio-hydroxogermanates, two classes of solid state proton conductors which are promising to be used as electrolytes in future intermediate temperature (200-500°C) fuel cells.This is an attractive temperature range for many applications but for which today's available electrolytes do not show satisfactory performance. LÄS MER

4. 3. Functional Oxide Materials exhibiting Ionic Conductivity for Future Energy Conversion Needs

   Författare :FRANCIS GACHAO KINYANJUI; Chalmers University of Technology; []
   Nyckelord :NATURVETENSKAP; TEKNIK OCH TEKNOLOGIER; NATURAL SCIENCES; ENGINEERING AND TECHNOLOGY; neutron diffraction; perovskites; oxygen deficient perovskites; BaSnO3; Rietveld refinements; BaZrO3; in-situ cells; proton conduction; deuteron position; Ba3In2ZrO8;

   Sammanfattning : Fuel cells are electrochemical devices that transform the chemical energy in hydrogen and oxygen into electrical energy at high efficiencies and produce only water vapour emissions. Materials with the perovskite or fluorite structure types are commonly employed as the ion conducting ceramic electrolyte membranes in intermediate and high temperature fuel cells. LÄS MER

5. 4. Neutron scattering for sustainable energy materials: investigations of proton dynamics in acceptor doped barium zirconates

   Författare :Daria Noferini; Chalmers University of Technology; []
   Nyckelord :NATURVETENSKAP; TEKNIK OCH TEKNOLOGIER; NATURAL SCIENCES; ENGINEERING AND TECHNOLOGY; neutron scattering; fuel cells; QENS; Proton conductors; perovskites; proton dynamics; energy materials;

   Sammanfattning : Proton conducting oxides are currently receiving considerable attention for their present or potential use as electrolytes in technological devices such as sensors and electrolysers and, in particular, solid oxide fuel cells, which are among the most promising apparatuses for energy conversion. One of the main challenges for these latter devices is to combine the advantages of a solid electrolyte with those of operational temperatures below 750 °C, which is currently hampered by insufficient conductivities in the targeted temperature range. LÄS MER

7. 5. Proton Conducting Ceramics; Synthesis, Characterization and Sample Cell Environments

   Författare :FRANCIS GACHAO KINYANJUI; Chalmers University of Technology; []
   Nyckelord :NATURVETENSKAP; TEKNIK OCH TEKNOLOGIER; NATURAL SCIENCES; ENGINEERING AND TECHNOLOGY; perovskites; neutron diffraction; Rietveld refinements; BaSnO3; in-situ cell; deuteron position; proton conduction; BaZrO3;

   Sammanfattning : Acceptor doped Perovskite ceramics have been shown to exhibit high levels of protonic conduction in humid atmospheres. However significant grain boundary resistance and long sintering times required to achieve sufficient grain size growth has hindered their widespread application as electrolyzers, fuel cells and gas separation membranes. LÄS MER