Simple Synthesis of Hollow Tin Dioxide Microspheres and Their Application to Lithium‐Ion Battery Anodes

Hollow tin dioxide (SnO₂) microspheres were synthesized by the simple heat treatment of a mixture composed of tin(IV ) tetrachloride pentahydrate (SnCl₄·5H₂O) and resorcinol–formaldehyde gel (RF gel). Because hollow structures were formed during the heat treatment, the pre‐formation of template and the adsorption of target precursor on template are unnecessary in the current method, leading to simplified synthetic procedures and facilitating mass production. Field‐emission scanning electron microscopy (FE‐SEM) images showed 1.7–2.5 μm sized hollow spherical particles. Transmission electron microscopy (TEM) images showed that the produced spherical particles are composed of a hollow inner cavity and thin outer shell. When the hollow SnO₂ microspheres were used as a lithium‐battery anode, they exhibited extraordinarily high discharge capacities and coulombic efficiency. The reported synthetic procedure is straightforward and inexpensive, and consequently can be readily adopted to produce large quantities of hollow SnO₂ microspheres. This straightforward approach can be extended for the synthesis of other hollow microspheres including those obtained from ZrO₂ and ZrO₂/CeO₂ solid solutions.     

The enhanced anodic performance of highly crimped and crystalline nanofibrillar carbon in lithium-ion batteries

To find a novel high-performance anode material for lithium-ion batteries, a new form of carbon characterized by highly crimped and crystalline nanofibrillar microtextures was produced by heat treating polyacrylonitrile/FeCl₃ hybrid precursor and subsequent thermal annealing under hydrogen gas. This form of carbon exhibits a rechargeable capacity of ∼630 mAh/g, which is superior to that of graphite, with a Coulomb efficiency of ∼70%. Further, the new form of carbon was found to exhibit an efficiency of lithium ion insertion/extraction of ∼100% in the voltage range from 0.06 to 0.80 V, with a capacity of ∼400 mAh/g. We speculate that this excellent capacity is due to the characteristic structure of this form of carbon, i.e. its highly entangled web-like hyperstructure consisting of highly crimped and crystalline nanofibrillar microtextures, which enables good permeation and has high resilience to volume deformation during the insertion/extraction of Li ions.     

Effect of blend composition on the morphology development of electrospun fibres based on PAN/PMMA blends

BACKGROUND: The aim of the work presented was to determine the morphology development and relevant change in fibre diameter of a binary polymer blend system during an electrospinning process. The size of the fibre diameter is one of the important factors determining the general properties of non‐woven mats formed from electrospun fibres. RESULTS: The morphology and diameter of electrospun polyacrylonitrile (PAN)/poly(methyl methacrylate) (PMMA) blends were investigated as a function of blend ratio using scanning electron microscopy. The diameter of the electrospun PAN/PMMA fibres decreased with increasing PMMA content up to 50 wt%, and then increased again with further increase of PMMA. After thermal treatment, the fibres shrank, and an irregularly shaped morphology was observed. CONCLUSION: The electrospinning of incompatible PAN/PMMA blends leads to a microphase‐separation morphology of fibres. A phase inversion occurs at a PMMA content of between 50 and 75 wt%. Due to the phase inversion, the fibre diameter shows a minimum value at the relevant composition. Copyright © 2008 Society of Chemical Industry     

Characterization and In-vitro Permeation Study of Stearic Acid Nanoparticles containing Hinokitiol

Lipid nanoparticles containing hinokitiol (HKL) were prepared by a melt–emulsification method. Stearic acid was used as a lipid for the matrix material of the nanoparticles. According to results from transmission electron microscopy (TEM) and dynamic light scattering (DLS), most of the nanoparticles were less than 100 nm. When nanoparticles containing HKL were scanned on a differential scanning calorimeter, no endothermic peak of HKL was observed. This means that HKL in the lipid matrix of the nanoparticles is in a dissolved state. In an 18-h permeation study using hairless mouse skin mounted on a diffusion cell, the amount of HKL encapsulated in the nanoparticles transported to the receptor cell was five to ten times more than for HKL dissolved either ethanol or propylene glycol. Therefore, stearic acid nanoparticles strongly enhanced permeation of the skin by HKL.     

Effect of ZnO contents at the surface of brass-plated steel cord on the adhesion property to rubber compound

An effect of ZnO concentration at the surface of brass-plated steel cord on the adhesion property between a rubber compound and a brass-plated steel cord was investigated. Cord composition was determined by an Auger microscope with Ar ion sputtering. Two different steel cords were prepared; one (cord A) had higher ZnO concentration at the cord surface compared to the other (cord B). Pull-out force of unaged adhesion sample of cord A was lower than that of cord B. But the adhesion durability of the humidity-aged adhesion sample of cord A was better than the latter. Rubber coverage of the pull out cord for the unaged adhesion samples of cord A was poor, indicating insufficient formation of an adhesion layer. Pull-out force of the thermal-aged adhesion samples decreased with increasing aging time and that of cord A was lower than that of cord B. The enhancement of rubber coverage during initial aging period could be explained by an additional formation of copper sulfide at the adhesion interphase and an increase of modulus of rubber compound adjacent to the adhesion layer. With further increases of aging time, adhesion interphase grew excessively and the physical property of rubber compound deteriorated significantly, such that rubber coverage of adhesion samples decreased markedly with increasing aging time.     

Determination of N2O Emissions Levels in the Selective Reduction of NOx by NH3 Over an On-Site-Used Commercial V2O5–WO3/TiO2 Catalyst Using a Modified Gas Cell

The formation of N₂O in NH₃–SCR deNO_x reaction over an on-site-used commercial V₂O₅–WO₃/TiO₂ catalyst has been measured using an on-line IR system with a modified gas cell. The N₂O could be formed by the SCR and NH₃ oxidation reactions. These two reactions were particularly enhanced with the on-site-used sample.     

Hypocholesterolemic Action of Fermented Brown Rice Supplement in Cholesterol-Fed Rats: Cholesterol-lowering Action of Fermented Brown Rice

Fermented rice products have been implicated in vascular injury and atherosclerosis in recent animal and human studies. In the current study, whether consumption of differently processed brown rice diets may change the cholesterol metabolism was evaluated in male Spraque Dawley (SD) rats after 28 d of treatment with diets containing 1% cholesterol. The experimental diets include corn starch alone as control diet (CO) or a diet containing a 50% substitute of CO; uncooked brown rice (UB), cooked brown rice (CB), lactic acid bacteria (LAB), brown rice mixed with LAB (BLAB), and fermented‐brown rice by LAB (FB), respectively. Among them, FB group elicited significantly lower levels of plasma and hepatic triglycerides, plasma total cholesterol, low‐density lipoprotein cholesterol (LDL‐C), and very low‐density lipoprotein cholesterol (VLDL‐C) by 33% to 50%, whereas higher levels of HDL‐C were elicited by 227% compared with the CO group (P < 0.05). These amelioration action on lipid profile in FB group appeared to correspondent to the higher excretions of fecal weight, triglyceride (TG), total cholesterol (TC), and bile acid (P < 0.05). Furthermore, sensory properties such as flavor liking, taste liking, and overall acceptability of the diet were significantly improved by the addition of fermented brown rice. Conclusively, fermented‐brown rice may have a potent cholesterol‐lowering benefits with sensory quality improvement of the diet.     

Polymer electrolyte membranes composed of an electrospun poly(vinylidene fluoride) fibrous mat in a poly(4‐vinylpyridine) matrix

Newly proposed polymer electrolyte membranes (PEMs) composed of an electrospun poly(vinylidene fluoride) (PVDF) fibrous mat embedded in a poly(4‐vinylpyridine) (P4VP) matrix were successfully fabricated in order to improve the mechanical and dimensional stabilities and ionic conductivity of membranes in lithium rechargeable batteries. Fourier transform infrared spectroscopic analysis showed that as a result of the use of a high voltage during electrospinning the crystalline structure of PVDF changed partially from α‐phase to β‐phase. Energy‐dispersive X‐ray spectroscopy confirmed the existence of crosslinked P4VP in the PVDF fibrous mat. The electrolyte uptakes of PVDF and PVDF/P4VP composite mats were higher than that of PVDF cast film. The tensile properties of PVDF/P4VP composite mat were considerably improved compared to those of the pristine PVDF fibrous mat under both dry and wet (soaked with electrolyte) conditions. In addition, the mechanical and dimensional stabilities of the PVDF/P4VP composite PEM were further enhanced due to crosslinking between the P4VP chains. Furthermore, the PVDF/P4VP composite PEM exhibited an ionic conductivity that was an order of magnitude higher than that of traditional PVDF film. © 2012 Society of Chemical Industry