Synergistic O2-/Li+ Dual Ion Transportation at Atomic Scale

Probing Electrochemical Cycling Stability of Li-ion Cathode Materials at Atomic-scale

Li-excess layered oxide high energy density materials are currently being considered as promising candidates for energy storage technologies in plug-in hybrid electric vehicles (PHEVs) or electric vehicles (EVs), owning to their high capacity (>250mAh/g), high energy density, and excellent safety.[1-3] Two major fundamental questions, however, must be resolved before their commercial implementa...

Li-Ion Cell Operation at Low Temperatures

Friction at the Atomic Scale

Everyone learns the basics of friction in high-school physics classes: the friction force experienced by a sliding object is proportional to the normal force that an object exerts on a surface. Remarkably, this extremely simple and empirical relation, known as Amontons’ Law, is still often used in creating the most technologically sophisticated machines and devices, even though friction is know...

Electrochemical and Structural Study of the Layered, “Li-Excess” Lithium-Ion Battery Electrode Material Li[Li1/9Ni1/3Mn5/9]O2

The overcapacity mechanism and high voltage process of the Li-excess electrode material Li[Li1/9Ni1/3Mn5/9]O2 are studied by solid-state NMR, X-ray diffraction, X-ray absorption spectroscopy, transmission electron microscopy, combined with galvanostatic and potentiostatic intermittent titration electrochemical measurements. The cycling performance is improved noticeably when the material is cyc...

Chip - Scale Atomic Clocks at NIST

We describe recent efforts to develop microfabricated atomic frequency references capable of supporting a wide variety of commercial and military systems such as global positioning and wireless communication. These devices are anticipated to eventually have a volume of 1 cm, dissipate less than 30 mW of electrical power and maintain a fractional frequency stability better than 10 over one hour....