Using neutrons to probe and understand battery interfaces
February 14, 2014 — Neutron reflectometry at the Spallation Neutron Source has revealed the composition and growth characteristics of the spontaneous chemical reaction layer formed between a silicon battery anode and an organic electrolyte that ultimately limits the capacity of the battery. We determined that a 3.
Anomalous Photodeposition of Ag on Ferroelectric Surfaces with Below Bandgap Excitation
February 14, 2014 — Photochemical deposition of elemental Ag nanoparticles on a ferroelectric substrate with sub bandgap transmitted white light indicates light confinement and non-linear optical phenomena. This innovation opens the pathway to unprecedented fine control and optimization of the growth of functional nanostructures for potential applications ranging from chemical sensing to high speed data transfer.
New imaging-based chemical analysis of atomic layers
February 14, 2014 — A new Z-contrast image analysis method now allows dopant atoms in two-dimensional materials to be located and quantified. With this ability, the distribution of dopants can be verified as the physical and chemical properties are modified. This new capability was used to study doped molybdenum disulfide in which the optical band gap was tuned between 1.85 and 1.
Enhancing the Efficiency of Solar Energy Conversion in Titania
February 04, 2014 — A new method that simultaneously incorporates chromium (Cr) and nitrogen (N) atoms as Cr-N pairs into titania yields a material with an extraordinarily large (> 1 eV) band gap reduction.
Evidence for non-uniform superconductivity in iron-based materials
January 31, 2014 — Multi-scale bulk and local electronic and structural studies on an iron-based superconductor have revealed, for the first time, an origin of non-bulk superconductivity. Understanding the role of chemical doping in causing superconductivity can potentially lead to the design of advanced high-temperature superconductors (HTS).
Air-Stable, High-Conduction Solid Electrolytes for Electrical Energy Storage
January 24, 2014 — A substituted Li4SnS4 solid electrolyte has been designed and demonstrated to have excellent air stability and exceptionally high ionic conductivity. This discovery opens the possibility for the design of new batteries that are safer and have higher energy density than today’s batteries.
Enhancing Tunneling Electroresistance by Interfacial Phase Transitions
January 22, 2014 — The tunneling electroresistance (TER) in ultrathin ferroelectric tunnel junctions (FTJs) is found to be critically dependent upon interface state phase transitions induced by the ferroelectric (FE) polarization.
Structure and Composition of Nanometer-Sized Nitrides in a Creep-Resistant Cast Austenitic Alloy
December 20, 2013 — The microstructure of a new and improved high-temperature creep-resistant cast austenitic alloy, CF8C-Plus, was characterized after creep-rupture testing at 1023 K (750ºC) and 100 MPa. Microstructures were investigated by detailed scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray spectroscopy (EDS).
Mapping solute excesses and curvature of grain boundaries
November 21, 2013 — A novel characterization method has been developed that enables complete characterizations of grain boundaries by atom probe tomography (APT) in terms of the orientation relationship of the adjacent grains, local variations of the habit plane, surface curvature, and the solute excesses over the surface of a grain boundary.
Orienting oxygen defects for enhanced oxygen reduction kinetics
November 20, 2013 — Functional oxygen defects are shown to result in a two orders of magnitude improvement of the catalytic oxygen reduction kinetics in epitaxial SrCoO2.5 films. This discovery will impact our understanding of the fundamental properties in multivalent transition metal oxides and provides technological insights into developing new strategies for advanced energy materials and systems.