In this work, a series of nitrogen-doped multi-walled carbon nanotubes (N-MWCNTs) with several weight percentages (0.1, 0.4, 0.8, and 1.0 wt.%) were synthesized by catalytic chemical vapor deposition (CCVD) technique. The N-MWCNTs were first characterized and then dispersed in high-density polyethylene (HDPE) polymer matrix to form a nanocomposite. The HDPE/N-MWCNT nanocomposite films were prepared by melt mixing and hot pressing; a good dispersion in the matrix and a good N-MWCNT-polymer interfacial adhesion have been verified by scanning electron microscopy (SEM). Raman spectroscopy measurements have been performed on prepared samples to confirm the presence and nature of N-MWNTs in HDPE matrix. The X-ray diffraction (XRD) analysis demonstrated that the crystalline structure of HDPE matrix was not affected by the incorporation of the N-MWNTs.

The specific energy of the existing lithium ion battery cells is limited because intercalation electrodes made of activated carbon (AC) materials have limited lithium ion storage capacities. Carbon nanotubes, graphene, and carbon nanofibers are the most sought alternatives to replace AC materials but their synthesis cost makes them highly prohibitive. Silicon has recently emerged as a strong candidate to replace existing graphite anodes due to its inherently large specific capacity and low working potential. However, pure silicon electrodes have shown poor mechanical integrity due to the dramatic expansion of the material during battery operation. This results in high irreversible capacity and short cycle life. We report on the synthesis and use of carbon and hybrid carbon-silicon nanostructures made by a simplified thermo-mechanical milling process to produce low-cost high-energy lithium ion battery anodes. Our work is based on an abundant, cost-effective, and easy-to-launch source of carbon soot having amorphous nature in combination with scrap silicon with crystalline nature. The carbon soot is transformed in situ into graphene and graphitic carbon during mechanical milling leading to superior elastic properties. Micro-Raman mapping shows a well-dispersed microstructure for both carbon and silicon. The fabricated composites are used for battery anodes, and the results are compared with commercial anodes from MTI Corporation. The anodes are integrated in batteries and tested; the results are compared to those seen in commercial batteries. For quick laboratory assessment, all electrochemical cells were fabricated under available environment conditions and they were tested at room temperature. Initial electrochemical analysis results on specific capacity, efficiency, and cyclability in comparison to currently available AC counterpart are promising to advance cost-effective commercial lithium ion battery technology. The electrochemical performance observed for carbon soot material is very interesting given the fact that its production cost is away cheaper than activated carbon. The cost of activated carbon is about $15/kg whereas the cost to manufacture carbon soot as a by-product from large-scale milling of abundant graphite is about $1/kg. Additionally, here, we propose a method that is environmentally friendly with strong potential for industrialization.

In this work, we investigated applicability of boron nitride (BN) and boron oxynitride (BNO) thin films to fabricate multilayer ceramic capacitors (MLCCs) for high temperature and high frequency applications. Advantages of BN include high temperature and chemical resistance, which should result in more compact and reliable devices. Deposited BN layers by a filamentless ion source assisted physical vapor deposition technique show a high thermal stability up to 1000 °C and a very high breakdown voltage of about 600 V/μm. A 15 mm × 15 mm capacitor geometry was picked to create a simpler packaging scheme. Rectangular electrodes are offset and layered to build up the capacitor and a metallization technique is used to produce high temperature oxidation resistant Au/Ti tab electrodes. We have seen consistent results in terms of: stable capacitance values versus frequency from 10 kHz to 2 MHz; near ideal phase angle (low parasitic inductance); and high quality factors values. Laboratory prototype capacitors with operating temperatures (350 °C - 700 °C) far superior to the leading sintering technologies (< 200 °C) were demonstrated. The dissipation factor and the capacitance change within a temperature range of 700 °C are ~ 2% total and ~10 ppm/ °C, respectively. Results on thermal and frequency behavior of single and multilayers self-packaged BN capacitors are presented. We have begun testing the capacitor's performance under actual operating conditions, together with other (R and L) components in a working RLC circuit at elevated temperature, and our preliminary results are reported.