Sökning: "BaZrO3"

Visar resultat 6 - 10 av 15 avhandlingar innehållade ordet BaZrO3.

  1. 6. Vibrational and Structural Characterisation in Two Perovskite Challenges: A Density Functional Theory Study

    Författare :Erik Jedvik Granhed; Chalmers University of Technology; []
    Nyckelord :NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; NATURAL SCIENCES; phonon; chemical expansion; materials modelling; oxyhydride; polaron; vibrational analysis; BaTiO3; BaZrO3; anti-ferrodistortive; density functional theory;

    Sammanfattning : The modelling of perovskites using density functional theory (DFT) can sometimes be a challenge with many different states very close in energy. In particular, the tilting of the inscribed octahedron, as well as the formation of electron polarons, leads to states with energy differences in the meV range. LÄS MER

  2. 7. 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

  3. 8. Significance of grain boundaries for transport phenomena in graphene and proton-conducting barium zirconate

    Författare :Edit Ahlberg Helgee; Chalmers University of Technology; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; graphene; density functional theory; phonons; proton conduction; grain boundaries; BaZrO3; interatomic model potentials;

    Sammanfattning : Grain boundaries can have a significant influence on the properties of polycrystalline materials. When determining the type and extent of this influence it is frequently useful to employ computational methods such as density functional theory and molecular dynamics, which can provide models of the grain boundary structure at the atomistic level. LÄS MER

  4. 9. On hydrogen point defects in perovskite oxides

    Författare :Erik Jedvik Granhed; Chalmers University of Technology; []
    Nyckelord :NATURVETENSKAP; NATURVETENSKAP; TEKNIK OCH TEKNOLOGIER; NATURAL SCIENCES; NATURAL SCIENCES; ENGINEERING AND TECHNOLOGY; density functional theory; oxyhydride; phonon; point defects; chemical expansion; polaron; BaZrO3; proton conductor; BaTiO3;

    Sammanfattning : Oxides based on the perovskite structure exhibit a surprisingly large diversity in materials properties and are found in many different applications, several related to clean energy technologies, such as solar cells, batteries and fuel cells. Many properties in materials are the result of lattice imperfections, commonly denoted \emph{defects}, and much effort is devoted to fine tuning materials properties through controlling the defects therein. LÄS MER

  5. 10. Synthesis, Structure and Proton Conduction of Substituted BaTiO3 and BaZrO3 Perovskites

    Författare :Seikh Mohammad Habibur Rahman; Chalmers University of Technology; []
    Nyckelord :deuteron position; Rietveld refinements; heavily doped oxygen deficient perovskite BaTiO3 BaZrO3 ; neutron total scattering; New proton conductor; X-ray and neutron powder diffraction; RMC modelling.; Impedance spectroscopy;

    Sammanfattning : Proton conducting oxides can be beneficial as electrolyte materials in devices such as fuel cells, hydrogen sensors etc. Proton conducting fuel cells (PCFCs), utilising H2 as fuel, stand out as a promising technology for future clean energy generation. LÄS MER