Part I: Electroreductive polymerization of nanoscale solid polymer electrolytes for three-dimensional lithium-ion batteries. Part II: Physical characterization and hydrogen sorption kinetics of solution-synthesized magnesium nanoparticles

The demand for secondary batteries with longer cycle life and higher power is greater now than ever. Lithium-ion batteries have emerged as the leading technology to store electrochemical energy and power our transportation needs. By employing solution-based nanotemplating methods, new three-dimensional cell configurations can exploit the high-surface area of nanowire array electrodes.The first system explored was the reductive electropolymerization of a zinc vinyl-bipyridine complex [Zn(vbpy)3]2+. The electrochemical synthesis covered the surface of planar and nanowire electrodes. Uniform deposition was observed by XPS and electrochemical "redox-probe" experiments. During the electropolymerization, the potentiodynamic cycle number determined the height of the polymer on the surface of a tin-doped indium-oxide (ITO) electrode. A relationship between the dielectric window and thickness of pZn(vbpy)3 exemplified how the physical characteristics of a polymer electrolyte are closely tied to the electrical characteristics.The second system of interest was the reductive "electrografting" of polymers with vinyl moieties. The reductive electropolymerization of glycidyl methacrylate (GMA) on two-dimensional electrodes was successful, but the conversion to nanowires is on-going research. Solid-state ionic conductivity, tested with a liquid metal eutectic, was observed on Cu2Sb. Ion transport wass induced by soaking the polymer in a 1M LiClO4/PC solution and drying.Copolymerization, an in situ doping method, was required to uniformly distribute Li-ions throughout the solid polymer electrolyte (SPE). The first step towards copolymerization was an in-depth analysis of the homopolymerization of an anionic monomer. Potassium 3-sulfopropyl acrylate (KSPA), soluble in water, was reductively polymerized onto multiple electrode surfaces. The growth was observed electrochemically and spectroscopically (UV-Vis). The reduction potential of the monomer on different electrodes was dependent on the work function of the material, but all depositions of pKSPA were non-uniform and electrically conducting. AFM and XPS measurements taken on polymer-modified ITO electrodes were the basis for the electrochemical island growth of anionic polymers.Electrochemical co-reduction of pGMA with an anionic monomer, pLiMA, uniformly deposited a polymeric layer. A "sweep-step" deposition potential profile successfully incorporated both monomers uniformly. ATR-IR spectroscopy provided some evidence for copolymerization. The curve-fitting analysis of the C 1s and Li 1s XPS HRES scans definitively evidenced the presence of pGMA-co- pLiMA on the surface of Cu2Sb. Variable-temperature solid-state impedance results indicated that the Tg of the copolymer must be lowered to increase the ionic conductivity. If SPEs are to be used in Li-ion batteries, then they must perform as well as common liquid organic electrolytes.However, the decomposition of carbonate-based solvents for Li-ion batteries also offered a route to a solid-state electrolyte. The decomposition of liquid electrolytes commonly used for batteries, such as propylene carbonate (PC), ethylene carbonate (EC), and dimethyl carbonate (DMC), produce a solid-electrolyte interface (SEI) layer on the surface of the all battery anode and cathodes. However, capacity retention was improved with the inclusion of the vinylene carbonate (VC) as an additive to the liquid electrolyte.Finding an effective storage medium is a significant challenge facing practical use of hydrogen as a fuel source. Light metal hydrides, such as MgH2, are a proposed solution for the efficient storage of H2 gas. The size of the solution-synthesized magnesium nanocrystals (MgNCs) was controlled by chemical composition of the reducing solution and the concentration of the magnesium precursor, magnesocene. The MgNCs are characterized by XRD and TEM. Extremely fastsorption kinetics is hypothesized to be due to the high-number of defect sites in the crystalline metal-hydride. The activation energy for H/D processes did not significantly change from bulk Mg. (Abstract shortened by UMI.)...