A5014171609- Advancements in Solid Oxide Fuel Cells
- Electronic and Structural Properties of Oxides
- Nanowire Synthesis and Applications
- Coral and Marine Ecosystems Studies
- Catalytic Processes in Materials Science
- Solid-state spectroscopy and crystallography
- Wind and Air Flow Studies
- Advanced Battery Materials and Technologies
- High-pressure geophysics and materials
- Coastal and Marine Management
- ZnO doping and properties
- Fluid Dynamics and Turbulent Flows
- Advancements in Battery Materials
- Advanced Condensed Matter Physics
- Ferroelectric and Piezoelectric Materials
- Glass properties and applications
- Marine Bivalve and Aquaculture Studies
- Phase-change materials and chalcogenides
- Fuel Cells and Related Materials
- Ionic liquids properties and applications
- Gas Sensing Nanomaterials and Sensors
- Particle Dynamics in Fluid Flows
University of California, Davis
1990-2023
This research demonstrates protonic conductivity in nanoscale fluorite- structured oxides as well YSZ at low temperatures. The photograph shows a water concentration cell of dense nanostructured (grain size ∼ 20 nm) Sm-doped ceria ceramic operating room temperature. One side (cathode) the is exposed to wet-air while other (anode) immersed into de-ionized water. current measured from 30 nA.
Grain core and grain boundary electrical dielectric properties of nanocrystalline yttria-stabilized zirconia (YSZ) were analyzed using a novel nano-Grain Composite Model (n-GCM). Partially sintered pellets with average sizes ranging from 10 to 73 nm over range temperatures AC impedance spectroscopy (AC-IS). Local conductivities, constants, effective space charge widths determined the fitted circuit parameters. Required constant data provided by AC-IS measurements single crystal YSZ...
Electron paramagnetic resonance (EPR) spectra of Gd(3+) ions in crystalline Ce(1-x-y)Gd(x)Y(y)O(2-[0.5*(x+y)]) (x=0.0025, y=0.10, and 0.25) with crystallite sizes ranging from 600 nm down to 5 have been measured at X-band Q-band near liquid He room temperatures. The EPR line shape is controlled by the low-symmetry surrounding a coordination environment one oxygen-vacancy seven oxygen nearest-neighbors forming GdO(7) polyhedra. These polyhedra are characterized wide distribution crystal field...
Homogeneous Ag–Ga–Ge selenide glasses display fast silver ion conduction at ambient temperature.
Through the use of a high-pressure modification spark plasma sintering method, it was possible to consolidate functional oxides (yttria- stabilized zirconia and doped ceria) high densities retain grain size < 20 nm. The role pressure on densification sintered samples demonstrated. had marked effect density at relatively low temperature but an insignificant temperature. It found that when prepared with such small sizes, these conduct protonically even temperatures as room dependence...
A comprehensive analysis of the ionic dynamics in a wide variety crystalline and glassy conductors, obtained recent studies using combination electrochemical impedance nuclear magnetic resonance spectroscopic techniques, is presented. These results demonstrate that crossover frequency, between frequency-independent dc conductivity frequency-dependent ac conductivity, corresponds to time scale "successful" diffusive hops mobile ions trapping sites structure. inter-site are typically compound...