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.
Local structures ‒ key to improved gas adsorption in carbon materials
September 23, 2013 — Combined results from electron microscopy, neutron scattering, and theory, illustrate the link between local structures and adsorption properties in carbon materials.
Epitaxial oxygen sponges as low temperature catalysts
September 10, 2013 — Fast and reversible redox reactions at considerably reduced temperatures are achieved by epitaxial stabilization of multivalent transition metal oxides. This illustrates the unprecedented potential of complex oxides for oxide-ionics, where oxidation state changes are used for energy generation, storage and electrochemical sensing.
Electronic properties of manganite surfaces robust against reduction
September 05, 2013 — While the broad range of properties of complex oxides degrade severely with decreasing oxygen content, it has now been shown that the electronic properties at their surfaces can remain unaffected in a reducing environment. This discovery carries important implications for the design of functional complex oxides for energy efficient catalysis and batteries that depend on these surface properties.
Fluid-like electrophoretic behavior observed in a solid crystal
September 03, 2013 — The position of coexisting mesoscale electronic phase domains in a complex oxide is shown to be controlled with electric fields in an electrophoretic process previously only observed in liquids. This discovery has important implications to our fundamental understanding of how electronic phase competition arises and persists while opening the door to new types of resistive switching possibilities.
Artificial SEI Enables High-Voltage Lithium-ion Batteries
September 03, 2013 — An artificial solid electrolyte interphase (SEI) of lithium phosphorus oxynitride (Lipon) enables the use of 5V cathode materials with conventional carbonate electrolytes in lithium-ion batteries.
Topotactic valence state control in epitaxial multivalent oxides
July 17, 2013 — Valence state control is demonstrated in a multivalent transition metal oxide (TMO) by topotactic transformation, i.e. the change of crystal structure via loss or gain of constituent elements.
Phase coexistence enables switching in strained BiFeO3
July 17, 2013 — Highly strained films of multiferroic BiFeO3 are shown to exhibit a complex and temperature dependent coexistence of multiple phases, with a minority phase being a prerequisite to ferroelectric switching of the majority.
LuFeO3: a new room-temperature multiferroic material
July 01, 2013 — Atomically resolved scanning transmission electron microscopy (STEM) image of LuFeO3, a new room-temperature multiferroic. Red dots indicate the “buckling” of the Lu oxide plane, consistent with the polar structure.