Commercial anodes with different state of charge are investigated by X-ray diffraction technique using Rietveld method for data collected with standard laboratory equipment. It is shown that full profile refinement gives good approximation for quantitative description of the charge/discharge process and may be used for estimation of real state of charge (SoC). Careful analysis of the diffraction profile with Rietveld method allows us to quantitatively distinguish the contribution of different LixC6 phases and estimate the real SoC.

Nanoelectrode sensor arrays were formed by depositing nanostructures of the electrocatalyst Prussian Blue onto an inert carbon support. The sensor thus obtained showed a high sensitivity toward hydrogen peroxide, with a detection limit of 1×10−9 mol L−1 (i.e., 0.03 ppb), and a broad linear calibration range, which extended over seven orders of magnitude (from 10−9 to 10−2 m L−1 H2O2, see graphic).

An iron-hexacyanide-covered microelectrode sensor has been used to continuously monitor the kinetics of hydrogen peroxide decomposition catalyzed by oxidized cytochrome oxidase. At cytochrome oxidase concentration ~1 µM, the catalase activity behaves as a first order process with respect to peroxide at concentrations up to ~300-400 µM and is fully blocked by heat inactivation of the enzyme. The catalase (or, rather, pseudocatalase) activity of bovine cytochrome oxidase is characterized by a second order rate constant of ~2·10(2) M(-1)·sec(-1) at pH 7.0 and room temperature, which, when divided by the number of H2O2 molecules disappearing in one catalytic turnover (between 2 and 3), agrees reasonably well with the second order rate constant for H2O2-dependent conversion of the oxidase intermediate F(I)-607 to F(II)-580. Accordingly, the catalase activity of bovine oxidase may be explained by H2O2 procession in the oxygen-reducing center of the enzyme yielding superoxide radicals. Much higher specific rates of H2O2 decomposition are observed with preparations of the bacterial cytochrome c oxidase from Rhodobacter sphaeroides. The observed second order rate constants (up to ~3000 M(-1)·sec(-1)) exceed the rate constant of peroxide binding with the oxygen-reducing center of the oxidized enzyme (~500 M(-1)·sec(-1)) several-fold and therefore cannot be explained by catalytic reaction in the a(3)/Cu(B) site of the enzyme. It is proposed that in the bacterial oxidase, H2O2 can be decomposed by reacting with the adventitious transition metal ions bound by the polyhistidine-tag present in the enzyme, or by virtue of reaction with the tightly-bound Mn2+, which in the bacterial enzyme substitutes for Mg2+ present in the mitochondrial oxidase.

4-methyl-2- [(2,2,3,3,4,4,5,5-octafluoropentyl)oxy]-1,3,2-dioxaphosphinane with the oxidation number of phosphorous (III) is used as an oxidative additive (OA) to a standard carbonate-based electrolyte for the high-voltage Li-ion cells with the overlithiated layered oxide Li 1.20 Ni 0.18 Mn 0.53 Co 0.09 O 2 (OLO) as a positive electrode. Electrochemical stability of electrolytes with and without OA is compared by linear sweep voltammetry, and characteristics of coin half and full cells are examined by means of cycling tests and electrochemical impedance spectroscopy. Presence of OA in electrolyte mixture provides noticeable improvement in Coulombic efficiency, capacity retention, and rate properties of the cells, most likely, through the formation of an interface layer on the OLOsurface due to the decomposition of OA. Morphology of OLO after cycling with OA-containing electrolyte is investigated by scanning electron microscopy and the presence of amorphous coating is observed; 31 P NMR analysis reveals that the products by the oxidation of OA are present on the cathode's surface. Differential scanning calorimetry data point out the substantially improved thermal stability of the OLO cathode after cycling in OA-containing electrolyte. Therefore, substituted dioxaphosphinanes may be considered as a promising structural pattern for design of new additives for the development of high-voltage electrolytes.

KNbO 3 in the form of films is a highly acclaimed material due to its potential application in surface acoustic wave (SAW), and nonlinear optic devices. Single-source powder flash evaporation MOCVD of epitaxial KNbO 3 films was accomplished, for the first time, with potassium tert-butoxide and niobium heteroligand complex, Nb(O i Pr) 4 (thd) used as volatile metal±or-ganic precursors. The microstructure of the films was found to be dependent on the substrate used (MgO or SrTiO 3 ) and deposition temperature. A new approach to reach cation stoichiometry of deposited films deficient in potassium, consisting of a post-deposition annealing with a KNbO 3 /K 3 NbO 4 powder mixture, was proposed. The device quality of the films was verified by high second harmonic generation (SHG) output. The effect of the oxygen non-stoichiometry of films on the phase transition temperature was proven.