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Lithium Fluoride as a Polysulfide Shuttle Inhibitor for Lithium Sulfur Chemistry

This invention imparts properties such as reinforcement, enhanced tensile strength, and/or electrical and thermal conductivity to composites. Lyndon B. Johnson Space Center, Houston, Texas In a lithium sulfur cell, the reduction of sulfur to lithium sulfide is a critical series of reactions that provides a large theoretical capacity of 1,672 mAh/g sulfur. One of many challenges in this system is the solubility of generated lithium polysulfides during the charge/discharge process. These polysulfides derived from the reduction of elemental sulfur are soluble in organic electrolytes, and can be reduced at the anode, causing an undesired reaction. Polysulfide species can also accumulate at the surface of the cathode and be further reduced to lower-order polysulfides such as Li2S2 or Li2S. The insulating nature of these lower-order polysulfides blocks the electron pathway on the carbon cathode.

Posted in: Briefs, TSP, Materials

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Fibers of Aligned Single-Wall Carbon Nanotubes and Process for Making the Same

This invention imparts properties such as reinforcement, enhanced tensile strength, and/or electrical and thermal conductivity to composites. Lyndon B. Johnson Space Center, Houston, Texas Single-wall carbon nanotubes (SWNTs) are fullerenes of closed-cage carbon molecules typically arranged in hexagons and pentagons. Commonly known as “buckytubes,” these cylindrical carbon structures have extraordinary properties, including high electrical and thermal conductivity, as well as high strength and stiffness. With intrinsic strength estimated to be on the order of 100 times that of steel, SWNTs are a possible strengthening reinforcement in composite materials. The intrinsic electronic properties of SWNTs also make them electrical conductors and useful in applications involving field mission devices such as flat-panel displays, and in polymers used for radio frequency interference and electromagnetic shielding that require electrical conductance properties.

Posted in: Briefs, Materials

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Enhancing MRI Contrast by Geometrical Confinement of Small Imaging Agents Within Nanoporous Particles

Lyndon B. Johnson Space Center, Houston, Texas Magnetic resonance imaging (MRI) has evolved into one of the most powerful, non-invasive diagnostic imaging techniques in medicine and biomedical research. The superior resolution and in-depth anatomical details provided by MRI are essential for early diagnosis of many diseases. Chemical contrast agents (CAs) have been widely used for improving the sensitivity and diagnostic confidence in MRI.

Posted in: Briefs, Materials

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Breaking Boundaries: Bioabsorbable Polymers in Device Design

It is well known that programming the performance of a bioabsorbable medical device is paramount to its success. But did you know that a large part of this programming takes place at the component level?

Posted in: Webinars, On-Demand Webinars, Materials, Medical

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Adhesion Reduction of Semiconductor Dicing Tape

Many semiconductor wafer processing techniques involve the fixing of a thin layer of dicing tape to a wafer during the final processing stages. To allow removal of the die from the tape, the adhesion properties of the tape may be reduced with exposure to high-intensity UV light.

Posted in: White Papers, Coatings & Adhesives, Materials

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Reducing Interconnection Weight in Autosports

In Formula 1 and other autosports, weight reduction is critical to competitive advantage. A few grams saved here and a few more saved there can add up to significant savings. There is also a move toward high-density packaging of electronics parts. As the electronics content of cars increases, the natural drive is to miniaturize the package to gain maximum efficiency in the use of space.

Posted in: Articles, Electronic Components, Electronics, Composites, Fiber Optics

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Watching Alloys Change Could Lead to Better Metals

If you put a camera in the ice machine and watched water turn into ice, the process would look simple. But the mechanism behind liquids turning to solids is actually quite complex, and understanding it better could improve design and production of metals. A recent investigation aboard the International Space Station (ISS) involved experiments using transparent alloys to observe microstructures that form at the point the material solidifies.

Posted in: UpFront, Materials, Physical Sciences

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