Holograms have been recorded in congruent LiTaO(3):Fe with continuous-wave laser light by use of a two-step process. Blue gating light (lambda=488 nm) sensitizes the crystals for holographic recording with red light (lambda=660 nm) of a diode laser. Refractive-index changes of as much as 1.0x10(-5) are achieved for intensities of the red light of 1 W/cm(2) . The saturation values are proportion...

Not simply small particles: pair distribution function analysis yields comprehensive insights into the electrochemical reaction of α-Fe(2)O(3) with lithium. The metallic Fe formed in this reaction was found to be defect-rich nanoparticles that restructure continuously without growing-an unusual characteristic likely linked to its highly reversible capacity.

Rate studies of the addition of n-BuLi in the presence of TMEDA to potentially chelating aldimines are consistent with a combination of monomer- and dimer-based mechanisms. Using mixtures of TMEDA and Et2O reveals cooperative solvation in which both Et2O and TMEDA coordinate to lithium at the monomer- and dimer-based transition structures. The four discrete mechanisms are affiliated with marked...

Li adsorption on isoreticular MOFs with metal Fe, Cu, Co, Ni and Zn was studied using density function theory. Li functionalization shows a considerable structural change associated with a volume change in isoreticular MOF-5 except for the Zn metal center. Hydrogen binding energies on Li functionalized MOFs are seen to be in the range of 0.2 eV, which is the desired value for an ideal reversibl...

The reaction between an uncharged Li2FeSiO4 (LFS) cathode and a LiPF6-EC/DMC electrolyte is revealed by in situ XANES in coin cells. This study shows clear evidence of delithiation and iron oxidation in LFS prior to cycling. Subsequent cycling appears to partially restore the original lithiation level, an observation that needs to be taken into consideration in future LFS development work.

A detailed study of eight systematically chosen Fe: LiNb03 crystals is presented. Correlation between the photorefractive sensitivity and various chemical properties of Fe:LiNb03 is investigated in order to ascertain optimum performance of the crystals in holographic storage and display applications. Concentrations of Fe 2+ and Fe 3+ ions have been determined from optical and EPR spectra, while...

High performance nanostructured iron fluorides with controllable sizes were successfully synthesized using oleylamine as a size tuning agent for the first time. They exhibited excellent cathode performances with large retensive capacities exceeding 200 mA h g(-1) after 50 cycles and outstanding rate performances of nearly 100 mA h g(-1) even at 10 C.

Reduction-oxidation (redox) reactions are the key processes that underlie the batteries powering smartphones, laptops, and electric cars. A redox process involves transfer of electrons between two species. For example, in a lithium-ion battery, current is generated when conduction electrons from the lithium anode are transferred to the redox orbitals of the cathode material. The ability to visu...

We present optical in situ investigations of lithium-ion dynamics lithium iron phosphate based positive electrodes. The change reflectivity these cathodes during charge and discharge is used to estimate apparent diffusion coefficients for the lithiation delithiation process entire electrode. Thereby, a scaling analysis transport applied, which clearly reveals its diffusive character. Results ar...