83 research outputs found

    Alginate-containing compositions for use in battery applications

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    A silicon-based anode comprises an alginate-containing binder. The many carboxy groups of alginate bind to a surface of silicon, creating strong, rigid hydrogen bonds that withstand battery cycling. The alginate-containing binder provides good performance to the anode by (1) improving the capacity of the anode in comparison to other commercially-available binders, (2) improving Columbonic efficiency during charging and discharging cycles, and (3) improving stability during charging and discharging cycles

    Alginate-containing compositions for use in battery applications

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    A silicon-based anode comprises an alginate-containing binder. The many carboxy groups of alginate bind to a surface of silicon, creating strong, rigid hydrogen bonds that withstand battery cycling. The alginate-containing binder provides good performance to the anode by (1) improving the capacity of the anode in comparison to other commercially-available binders, (2) improving Columbonic efficiency during charging and discharging cycles, and (3) improving stability during charging and discharging cycles

    Silicon-based anode and method for manufacturing the same

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    A silicon-based anode comprising silicon, a carbon coating that coats the surface of the silicon, a polyvinyl acid that binds to at least a portion of the silicon, and vinylene carbonate that seals the interface between the silicon and the polyvinyl acid. Because of its properties, polyvinyl acid binders offer improved anode stability, tunable properties, and many other attractive attributes for silicon-based anodes, which enable the anode to withstand silicon cycles of expansion and contraction during charging and discharging

    Magnetically Responsive Silicon Carbide Whiskers for Enhanced Nanocomposite Materials

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    Boeing’s 787 Dream Liner, GE’s wind turbine blades, and Ferrari’s F1 chassis demonstrate the accomplishments of designed directionality in carbon fiber/epoxy composites. The aerospace, energy and transportation industries demand composite material with enhanced multifunctional properties including ultimate strength and toughness. Despite sizeable improvements, composite utilization is limited by the fiber’s low surface-area-to-volume ratio (specific surface). Orientation in man-made composites has been the key to effective strengthening of materials under mechanical load and compensating for intrinsic limitations of the current technology. Nanocomposites can drive performance to new heights by increasing the fiber to matrix interaction. Thus far, the embedding of nanomaterials into composites has been achieved, but directional arrangement has proved to be a challenging task. Even with advances in insitu, shear, and stress orientation, these methods are both difficult to control and unreliable, hampering nanocomposite improvements. Therefore, the implementation of nanomaterials with a natural ability to orient along a magnetic field will create a controlled system with precisely designed morphology. To this end, the proposed project has develop an effective approach for the design of magnetically active nanowhiskers to form 2D aligned structures in a polymer matrix, creating novel nanocomposites with enhanced mechanical properties

    Surface modification of substrates

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    The present invention is directed to a practically universal surface modification process and the materials thereby obtained. In general, the process includes initial epoxy modification of a substrate surface by attachment of an epoxy-containing polymer to the surface. Following attachment of the polymer, still-existing epoxy groups on the polymer may then cross-link the polymer to form a unified anchoring layer on the surface. Other epoxy groups in the anchoring layer, not utilized in forming the layer may be used to graft surface modifying materials to the surface. For instance, macromolecules, biomolecules, polymers, and polymerization initiators may be grafted to the surface via the anchoring layer

    Surface modification of substrates

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    The present invention is directed to a practically universal surface modification process and the materials thereby obtained. In general, the process includes initial epoxy modification of a substrate surface by attachment of an epoxy-containing polymer to the surface. Following attachment of the polymer, still-existing epoxy groups on the polymer may then cross-link the polymer to form a unified anchoring layer on the surface. Other epoxy groups in the anchoring layer, not utilized in forming the layer may be used to graft surface modifying materials to the surface. For instance, macromolecules, biomolecules, polymers, and polymerization initiators may be grafted to the surface via the anchoring layer

    On-chip infrared sensors: redefining the benefits of scaling

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    Infrared (IR) spectroscopy is widely recognized as a gold standard technique for chemical and biological analysis. Traditional IR spectroscopy relies on fragile bench-top instruments located in dedicated laboratory settings, and is thus not suitable for emerging field-deployed applications such as in-line industrial process control, environmental monitoring, and point-of-care diagnosis. Recent strides in photonic integration technologies provide a promising route towards enabling miniaturized, rugged platforms for IR spectroscopic analysis. It is therefore attempting to simply replace the bulky discrete optical elements used in conventional IR spectroscopy with their on-chip counterparts. This size down-scaling approach, however, cripples the system performance as both the sensitivity of spectroscopic sensors and spectral resolution of spectrometers scale with optical path length. In light of this challenge, we will discuss two novel photonic device designs uniquely capable of reaping performance benefits from microphotonic scaling. We leverage strong optical and thermal confinement in judiciously designed micro-cavities to circumvent the thermal diffusion and optical diffraction limits in conventional photothermal sensors and achieve a record 104 photothermal sensitivity enhancement. In the second example, an on-chip spectrometer design with the Fellgett's advantage is analyzed. The design enables sub-nm spectral resolution on a millimeter-sized, fully packaged chip without moving parts.National Science Foundation (U.S.) (Award 1506605)United States. Department of Energy (Grant DE-NA0002509

    Textile Dyeing Using Nanocellulosic Fibers

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    Disclosed are various embodiments for dyeing a material using a dyed nanocellulose dispersion, thereby reducing or eliminating the need for water in dyeing materials, such as fabrics and textiles. A dyed nanocellulose dispersion or gel may be prepared from wood pulp fibers using a homogenizer and a dye, wherein the dyed nanocellulose dispersion comprises nanosized cellulose fibrils. The dyed nanocellulose gel may comprise an approximate concentration of 0.5% to 6%. The dyed nanocellulose dispersion may be applied to a material, such as a fabric or textile material. The fabric or textile material can be dried resulting in a dyed material

    Development of novel integrated bio/chemical sensor systems using chalcogenide glass materials

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    This paper reviews ongoing progress in the design and fabrication of new, on-chip, low loss planar molecular sensors. We report the details of device design, material selection and manufacturing processes used to realise high-index-contrast (HIC), compact micro-disk resonators. These structures have been fabricated in thermally evaporated As- and Ge-based chalcogenide glass films with PDMS (polydimethylsiloxane) micro-fluidic channels using standard UV lithography. Discussed are findings that demonstrate that our novel chalcogenide-based micro-fluidic device can be used as highly sensitive refractive index sensors

    Mid-infrared materials and devices on a Si platform for optical sensing

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    In this article, we review our recent work on mid-infrared (mid-IR) photonic materials and devices fabricated on silicon for on-chip sensing applications. Pedestal waveguides based on silicon are demonstrated as broadband mid-IR sensors. Our low-loss mid-IR directional couplers demonstrated in SiNx waveguides are useful in differential sensing applications. Photonic crystal cavities and microdisk resonators based on chalcogenide glasses for high sensitivity are also demonstrated as effective mid-IR sensors. Polymer-based functionalization layers, to enhance the sensitivity and selectivity of our sensor devices, are also presented. We discuss the design of mid-IR chalcogenide waveguides integrated with polycrystalline PbTe detectors on a monolithic silicon platform for optical sensing, wherein the use of a low-index spacer layer enables the evanescent coupling of mid-IR light from the waveguides to the detector. Finally, we show the successful fabrication processing of our first prototype mid-IR waveguide-integrated detectors
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