Ultra-lightweight rechargeable battery with enhanced gravimetric energy densities >750 Wh kg in lithium-sulfur pouch cell.

Lithium-sulfur (Li-S) rechargeable batteries have been expected to be lightweight energy storage devices with the highest gravimetric energy density at the single-cell level reaching up to 695 Wh kg, having also an ultralow rate of 0.005 C only in the first discharge. Sulfurized polyacrylonitrile (SPAN) is one of the sulfur-based active materials, which allows more freedom in the Li-S cell design because it shows no undesirable reactions with electrolyte solutions.

Ethylene polymerization using -Heterocyclic carbene complexes of silver and aluminum.

Various transition metal catalysts have been utilized for ethylene polymerization. Silver catalysts have attracted less attention as the catalysts, but are potential for production of high molecular weight polyethylene. Herein, we report that silver complexes with various -heterocyclic carbene (NHC) ligands in combination with modified methylaluminoxane (MMAO) afford polyethylene with high molecular weight (melting point over 140°C).

Property development for biaxial drawing of ethylene-tetrafluoroehtylene copolymer films and resultant fractural behavior analyzed by in situ X-ray measurements.

The property development of the ethylene-tetrafluoroethylene copolymer (ETFE) membrane induced by simultaneous biaxial drawing was investigated. Commonly, tensile strength can be increased by drawing; conversely, tear resistance decreases. In this study, the balance between tensile strength and tear resistance for the resultant ETFE membrane was optimized achieved by a combination of lamination of low molecular weight (LMW) and high molecular weight (HMW) layers and subsequent biaxial drawing.

Size-selective diffusion in nanoporous but flexible membranes for glucose sensors.

A series of nanoporous membranes prepared from polyethylene-block-polystyrene were applied for size-selective diffusion of glucose and albumin molecules. Millimeter-sized test cells for characterization of such molecular diffusions were designed assuming an implantable glucose sensor. The prepared nanoporous membrane exhibits excellent flexibility and toughness compared to conventional nanoporous membranes of brittle alumina.

Phase transitions during heating of melt-drawn ultrahigh molecular weight polyethylenes having different molecular characteristics.

Changes in the crystalline structure during heating of melt-drawn ultrahigh molecular weight polyethylenes (UHMW-PEs) having different molecular characteristics were analyzed by in situ wide-angle X-ray diffraction measurements. A phase transition from the orthorhombic into the hexagonal phase was observed for all samples, but the perfection was enhanced and the possible temperature window for the hexagonal phase was greater for the sample containing only a higher molecular weight component. In contrast, an increase in retractive stress during heating was confirmed for the sample containing a lower molecular weight component, reflecting melting of the folded-chain crystal (FCC).

Molecular weight segregation on surfaces of polyethylene blended films as estimated from nanoscratch tests using scanning probe microscopy.

Nanoscratch tests using scanning probe microscopy (SPM) were performed on films prepared from two polyethylene (PE) materials polymerized by using a metallocene catalyst system with different molecular weights (MWs). Blended samples were prepared by dissolving both PE materials at various ratios in hot p-xylene. The pure and blended samples were compression molded into films at 180 degrees C for different holding times in the molten state.

Surface-deformation characteristics of uniaxially oriented poly(ethylene terephthalate) film as evaluated from nanoscratch tests with scanning probe microscopy.

The surface-deformation characteristics of uniaxially drawn poly(ethylene terephthalate) (PET) film were successfully evaluated with multiline scratch tests using scanning probe microscopy (SPM) on a nanometer scale. The PET film was prepared by compression molding from the melt, followed by quenching in ice water. The obtained amorphous film was drawn uniaxially below its glass-transition temperature, and the resultant surface roughness could be reduced to within 5 nm.