No abstract

Commercial purity Mg, Mg-RE alloys ZE10A (UNS M11600), and EV31A (UNS M12310) were evaluated in the as-received condition for potential application as anode for Mg-air battery. Anodic and cathodic polarization studies were performed in 0.6 M NaCl, 0.5 M NaNO3 and 0.1 M Na2SO4 electrolytes. Hydrogen evolved during anodic polarization was measured at different potentials. Electrochemical impedance spectroscopy was carried out at open circuit conditions. The results showed that commercial purity magnesium had higher corrosion resistance than the Mg-RE alloy specimens in all the electrolytes tested. All the specimens showed negative difference effect (NDE) where the rate of hydrogen evolution increased with increased anodic polarization. The NDE was more pronounced on ZE10A than on other materials. The rate of hydrogen evolution was about three times higher in NaCl solution than in other two solutions. The results suggest that ZE10A could be a potential anode material for Mg-air battery due to its high anodic activity in spite of the observed NDE.

Cyclic voltammetry CV), square wave voltammetry (SWV), and electrochemical impedance spectroscopy measurements were carried out in 1 and 5 wt% TeCl4 containing LiCl-KCl eutectic molten salt at 450 °C using tungsten and glassy carbon as working electrodes. Reduction of Te(IV) to Te(0) occurred in three steps at potentials more negative than −0.4 VAg/AgCl. The Te(0) was further reduced to Te2− at more negative potentials. Formation of Te2− was observed at potentials more negative than −2.2 VAg/AgCl. Diffusivities of Te4+, Te2+, and Te2− and their formal potentials were estimated from the CV data. The diffusion coefficients of Te4+, Te2+ and Te2− were 0.9 × 10−5, 3.8 × 10−5, and 1.5 × 10−5 cm2 s−1, respectively in the 1 wt% TeCl4 containing LiCl-KCl molten salt. The diffusivity of Te species generally decreased with increase in the concentration of TeCl4.

Bismuth oxides have been researched over the last several years due to its low cost compared to other metal oxides. During our experiments two methods were researched to improve the performance of Bi2O3 for supercapacitance capabilities. One method was using an electrodeposition technique to deposit the bismuth sesquioxide onto ITO glass, another was creating Bi2O3 powder and pressing it into a Ni foam substrate. For electro-deposition method, α phase showed the highest capacitance of 2027 F/g when calculated from cyclic voltammetry, while charge discharge cycles it was 24 F/g. Ni foam powder ß phase had the greater capacitance of 2559 F/g for cyclic voltammetry and charge discharge was 56 F/g.