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.
Shaking the bonds: Atomic vibrations drive insulator to metal
November 10, 2014 — Neutron and x-ray experiments, coupled with large-scale first-principles calculations have revealed the origin of the metal–insulator transition in vanadium dioxide, an intractable question in phase stability for more than 50 years.
Stable Separator Identified for High-Energy Batteries
November 04, 2014 — State-of-the-art scanning transmission electron microscopy (STEM) unveiled the structural stability of lithium lanthanum zirconium oxide (LLZO) garnet in aqueous media.
New Method Probes Nanoscale Electrostatic Effects
October 29, 2014 — Electrostatic forces were used to observe charge transfer at the nanoscale between metal and dielectric materials. A new technique was developed to access information about charge transfer, which is a key component in processes such as storage in flash memories, electroforming in memristors, surface electrochemistry, and triboelectricity.
Digital Transfer Growth of Patterned 2D Metal Chalcogenides by Confined Nanoparticle Evaporation
October 28, 2014 — Researchers demonstrated a novel growth technique for the controlled synthesis of monolayer or few-layer 2D metal chalcogenide crystals that should prove useful for their scaled production for optoelectronic and energy applications.
A High-Energy Solid State Battery with an Extremely Long Cycle Life
October 15, 2014 — A high-voltage (5V) solid state battery has been demonstrated to have an extremely long cycle life of over 10,000 cycles. For a given size of battery, the energy stored in a battery is proportional to its voltage. Conventional lithium-ion batteries use organic liquid electrolytes that have a maximum operating voltage of 4.3 V.