Lithium storage properties of Li2MoO3 and its effect as a cathode additive in full cells

High-performance lithium–ion batteries (LIBs) are the main development direction of future energy storage devices. However, most LIBs still face a problem of high first irreversible capacity loss. Pre-lithiation technology can increase the content of active lithium source and compensate the loss of active lithium during the first cycle. Adding lithium supplement additive to the cathode provides an effective way to improve the electrochemical performance of LIBs. Here, Li2MoO3 has been investigated as a cathode additive in the full cells. In order to optimize its preparation, Li2MoO3 has been prepared by three different methods, including solid-phase method, liquid-phase method and ultrasonic method. Based on material characterization and electrochemical performance tests, Li2MoO3 material prepared by liquid-phase method shows the best lithium storage properties and chosen as a cathode additive in the LiNi[Formula: see text]Co[Formula: see text]Mn[Formula: see text]O2/SiO@C full cells. The addition of Li2MoO3 has successfully improved the electrochemical performance of the full cell. The first discharge specific capacity increases from 103.9 mAh g[Formula: see text] to 130.4 mAh g[Formula: see text]. In short, Li2MoO3 material is a promising cathode additive for LIBs.

Effects of Oxygenated Acids on Graphene Oxide: The Source of Oxygen-Containing Functional Group

Graphene oxide is an important member of the graphene family which has a wide range of applications. The chemical method, especially the liquid phase method, is one of the most common and important methods for its preparation. However, the complex solution environment not only gives them rich structure, but also brings great challenges for its large-scale industrial synthesis. In order to better realize its industrial application, it is important to understand its structure, such as the source of oxygen-containing functional groups. Here we studied the contribution of four oxygenated acids to oxygen-containing functional groups in Hummers’ method using first principles. We found that the permanganic acid molecules that exist instantaneously due to energy fluctuations can be the source of oxygen-containing functional group. In addition, Stone-Wales defect have a certain effect on the formation of oxygen-containing functional groups, but this effect is not as good as that of solvation effect. This work provides a guide for exploring the source of oxygen-containing functional groups on graphene oxide.

Enhancement of the properties of a Beta-GA2O3-based diode using fluorine-doped Ga2O3 films deposited by a liquid-phase method

The purpose of this research is to investigate a low-cost liquid-phase deposition (LPD) method for preparing gallium oxide ([Formula: see text]-Ga2O[Formula: see text] films. This approach has the advantages of being easy and not requiring a vacuum, and it is suitable for large-area manufacturing. First, the LPD method was used to precipitate GaOOH particles below a pH of 8 and at 80[Formula: see text]C; these were used as the precursor for the gallium oxide ([Formula: see text]-Ga2O[Formula: see text] films. Ammonium fluoride (NH4F) with concentrations of 0.1, 0.3, and 0.5 M was added to the solution to form fluorine-doped (F-doped) GaOOH. The precipitated F-doped GaOOH powders were analyzed using an energy-dispersive X-ray spectroscopy (EDS) on a field emission scanning electron microscope to identify elemental F, Ga, and O. We found that the concentration of F ions increased with the NH4F concentration. The deposited films were then annealed at 900[Formula: see text]C for 4 h to transform the F-doped GaOOH into F-doped [Formula: see text]-Ga2O3. EDS was used to analyze the F-doped [Formula: see text]-Ga2O3 films, and we found that their F[Formula: see text] ion concentration also increased with the NH4F concentration. XPS analysis was used to confirm the existence of F[Formula: see text] ions in the F-doped [Formula: see text]-Ga2O3 films. The analyzed results also showed that as the NH4F concentration increased, the electrical performance of F-doped gallium oxide improved. Finally, the F-doped [Formula: see text]-Ga2O3 films were used to fabricate F-doped [Formula: see text]-Ga2O3/p[Formula: see text]-Si junction diodes, and their J–V properties were thoroughly investigated. We found that the rectification characteristics of the F-doped [Formula: see text]-Ga2O3/p[Formula: see text]-Si diodes could be significantly improved.

Optimization of the composition of solid dispersion of quercetin

Increasing the solubility of drugs is one of the most important problems in pharmacy, because most manufactured pharmaceutical substances are sparingly soluble. Typically, such compounds represent Classes II and IV in the biopharmaceutical classification system, which is based on the classification of pharmaceutical substances by solubility and permeability. For poorly soluble substances, the limiting step of the absorption process is usually the degree and dissolution rate, so in the pharmaceutical development, much attention is paid to their improvement. To solve this problem, the technology of solid dispersions creation is used. The aim of the work was to optimize the composition of quercetin solid dispersion, whose therapeutic use is limited due to its degree of solubility in an aqueous medium. Objects of the study were samples of solid dispersions of quercetin with different carriers: polyethyleneoxide-6000, β-cyclodextrin and polyvinylpyrrolidone obtained in a ratio of 1:1 and 1:2 by liquid phase method, with and without the addition of a solvent. As a solvent, ethanol was used. To determine the optimal composition of solid dispersions, a mathematical planning method using the MathCad package and Excel software was used. In the work, a dispersion analysis was performed upon the results of the experimental studies. The ranked series of advantages of the carrier and solvent influence on solubility of solid dispersions samples are shown. To determine the amount of carrier in the solid dispersion, the theory of multi-vector optimization was applied. According to the results of the conducted studies, the optimal value of quercetin and PEO-6000 ratio is 1:2. The obtained results can be used in the development of the composition and technology of solid dispersions of active pharmaceutical ingredients insoluble in the aqueous medium.

From Amorphous Red Phosphorus to a Few Layers of Black Phosphorus: A Low-cost and Efficient Preparation Process

In this work, we present an efficiency synthesis method of phosphorene from red phosphorus by means of black phosphorus. The latter was synthesized by using copper, tin, tin iodide and red phosphorus as precursor at low pressure-temperature. Characterizations with powder X-ray diffraction, scanning electron microscopy (SEM), energy dispersive spectrometry (EDX), high-resolution TEM (HR-TEM) and Raman spectroscopy were performed to confirm the high quality and purity of black phosphorus crystal. Liquid phase method was used to exfoliate black phosphorus to phosphorene in N-methyl-2-pyrrolidone (NMP) as solvent. Atomic force microscopy and STEM were used to confirm the exfoliation of black phophorus in a few layers of phophorene. Keywords: 2D materials, Red phosphorus, Black phosphorus, Phosphorene, Liquid-phase exfoliation.

Rapid Assembly of Oligosaccharides by Using a Hydrophobic Tag-Assisted Liquid-Phase Method

A 3,5-didocosyloxybenzyl alcohol tag that was introduced at the anomeric position of the carbohydrate acceptor was applied in the assembly of a pentasaccharide. The intrinsic high solubility in nonpolar solvent and precipitation properties in polar solvent are crucial features of this tag. Thus, rapid and simple precipitation-centrifugation can be conducted throughout the synthetic route at each step to ease work-up and purification processes, and reduce the amount of solvent required. This method provides an efficient, environmental-friendly, and economical approach to synthesize complex oligosaccharides.