Thin magnetic crystals are path to ferromagnetic graphene
January 23, 2015 — Chromium triiodide (CrI3) crystals were identified as a promising platform for studying how magnetism can enhance electronic behaviors in materials that are only a few atoms thick. Development of such ultra-thin magnetic materials may be crucial for continued advancement in miniaturization and performance enhancement of electronic devices.
Researchers map atomic movements that trigger voltage fade in high-energy-density batteries
January 22, 2015 — ORNL researchers performed powder neutron diffraction experiments on high-voltage, high-capacity lithium- and manganese-rich nickel−manganese−cobalt layered composite oxides (LMR-NMCs) to obtain insights into the degradation mechanisms causing voltage fade in this high-potential cathode material.
Scientists Connect Thermoelectric Materials and Topological Insulators
January 20, 2015 — Quantum mechanical calculations of electronic structure and transport for Bi2Te3 and its sister material Bi2Te2Se solved the long-standing puzzle of why many materials that are topological insulators are also excellent thermoelectrics.
Rig designed to study effect of vibration on spent nuclear fuel
January 16, 2015 — Researchers have developed an innovative system, called Cyclic Integrated Reversible-bending Fatigue Tester (CIRFT), to test and evaluate the mechanical behavior of spent nuclear fuel (SNF) under normal transportation conditions. The SNF fatigue data generated by CIRFT technology are essential in assisting back end fuel cycle reliability investigation.
Synergy of Ionization with Defects Creates Amorphous Track
January 13, 2015 — A colossal synergy, orders of magnitude larger than anything previously reported, has been discovered to occur between electronic energy loss by ions and pre-existing atomic defects created by elastic energy loss in single-crystal strontium titanate (SrTiO3). This synergy results in the formation of nanometer-sized amorphous tracks, but only in the region with pre-existing defects.
Facets and disorder hold key to battery materials performance
December 10, 2014 — A synergistic combination of atomic-scale experiment and theory identify Ni antisites as the predominant defects in a lithium–manganese-rich cathode material. In addition, their formation energies are facet-dependent, with larger defect concentrations observed at open (010) facets.
Single Supported Atoms Participate in Catalytic Processes
December 04, 2014 — Researchers recently predicted and demonstrated that single supported Pt atoms are highly active for NO oxidation. This work will impact determining the optimum loading of noble metals on emissions-treatment catalysts and design of low-temperature catalysts.
Understanding Why Silicon Anodes of Lithium-Ion Batteries Are Fast to Discharge but Slow to Charge
December 02, 2014 — Silicon anodes for lithium-ion batteries are capable of quickly delivering high power but charge at a much lower rate. High-power and high-rate performance of batteries is determined by the intrinsic electrochemical reaction rates. The forward and backward reaction rates for reversible electrochemical reactions are not necessarily identical.
Crown Ethers in Graphene Bring Strong, Selective Binding
November 14, 2014 — Researchers discovered the long-sought crown ether structures with perfect rigidity in oxidized atomic-scale holes in graphene. Calculations indicate that these “super crown ethers” provide unprecedented binding strength and selectivity. Thus, new supramolecular materials in which metal ions are trapped into arrays within the graphene plane are possible.
Strain-induced vacancy stability shown across an interface
November 12, 2014 — Density functional theory (DFT) calculations show that among the four types of (001) SrTiO3 | (001) MgO interface structures, the TiO2-terminated SrTiO3 containing electrostatically attractive Mg–O and Ti–O ion–ion interactions form the most stable interface.