Study of Copper–Nickel Nanoparticle Resistive Ink Compatible with Printed Copper Films for Power Electronics Applications

This paper is focused on copper–nickel nanoparticle resistive inks compatible with thick printed copper (TPC) technology, which can be used for power substrate manufacturing instead of conventional metallization techniques. Two types of copper–nickel inks were prepared and deposited by Aerosol Jet technology. The first type of ink was based on copper and nickel nanoparticles with a ratio of 75:25, and the second type of ink consisted of copper–nickel alloy nanoparticles with a ratio of 55:45. The characterization of electrical parameters, microstructure, thermal analysis of prepared inks and study of the influence of copper–nickel content on electrical parameters are described in this paper. It was verified that ink with a copper–nickel ratio of 55:45 (based on constantan nanoparticles) is more appropriate for the production of resistors due to low sheet resistance ~1 Ω/square and low temperature coefficient of resistance ±100·10−6 K−1 values. Copper–nickel inks can be fired in a protective nitrogen atmosphere, which ensures compatibility with copper films. The compatibility of copper–nickel and copper films enables the production of integrated resistors directly on ceramics substrates of power electronics modules made by TPC technology.

Ionic Liquid-Derived Carbon-Supported Metal Electrocatalysts as Anodes in Direct Borohydride-Peroxide Fuel Cells

Three different carbon-supported metal (gold, platinum, nickel) nanoparticle (M/c-IL) electrocatalysts are prepared by template-free carbonization of the corresponding ionic liquids, namely [Hmim][AuCl4], [Hmim]2[PtCl4], and [C16mim]2[NiCl4], as confirmed by X-ray diffraction analysis, scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy and Raman spectroscopy. The electrochemical investigation of borohydride oxidation reaction (BOR) at the three electrocatalysts by cyclic voltammetry reveals different behavior for each material. BOR is found to be a first-order reaction at the three electrocatalysts, with an apparent activation energy of 10.6 and 13.8 kJ mol−1 for Pt/c-IL and Au/c-IL electrocatalysts, respectively. A number of exchanged electrons of 5.0, 2.4, and 2.0 is obtained for BOR at Pt/c-IL, Au/c-IL, and Ni/c-IL electrodes, respectively. Direct borohydride-peroxide fuel cell (DBPFC) tests done at temperatures in the 25–65 °C range show ca. four times higher power density when using a Pt/c-IL anode than with an Au/c-IL anode. Peak power densities of 40.6 and 120.5 mW cm−2 are achieved at 25 and 65 °C, respectively, for DBPFC with a Pt/c-IL anode electrocatalyst.

Nickel nanoparticle-decorated reduced graphene oxide/WO3 nanocomposite – a promising candidate for gas sensing

We report for the first time the combination of WO3 sensing elements with a non-noble metal–carbon composite, namely a nickel metal nanoparticle–carbon composite (Ni@rGO). Previous work with WO3 had used either NiO (as part of the WO3 lattice), solely carbon, Pd-surface decorated WO3 (Pd@WO3), or Pd or Pt@carbon@WO3. We demonstrate the gas response for pure WO3, rGO/WO3 and Ni@rGO/WO3 sensing elements towards NO2 and acetone in air as well as towards CO in N2. The addition of 0.35 wt % Ni@rGO composite to WO3 enables the increase of the sensory response by more than 1.6 times for NO2 vapors. The gas response towards acetone using 0.35 wt % Ni@rGO/WO3 composite was 1.5 times greater for 3500 ppm than for 35,000 ppm acetone. For 0.35 wt % Ni@rGO/WO3 composite and CO gas, a response time (T res) of 7 min and a recovery time (T rec) of 2 min was determined.