9,968 research outputs found
Electrolyte management in porous battery components. Static measurements
The interaction between the porous hydrogen and nickel electrodes and microporous separator with respect to electrolyte management in nickel/hydrogen cells has been investigated. The distribution of electrolyte among the components has been measured and correlated with the pore size distributions, total void volume, and resistance of a variety of electrodes and separators. Calculations are used to show the effects of systematically varying these properties
Pore size engineering applied to the design of separators for nickel-hydrogen cells and batteries
Pore size engineering in starved alkaline multiplate cells involves adopting techniques to widen the volume tolerance of individual cells. Separators with appropriate pore size distributions and wettability characteristics (capillary pressure considerations) to have wider volume tolerances and an ability to resist dimensional changes in the electrodes were designed. The separators studied for potential use in nickel-hydrogen cells consist of polymeric membranes as well as inorganic microporous mats. In addition to standard measurements, the resistance and distribution of electrolyte as a function of total cell electrolyte content were determined. New composite separators consisting of fibers, particles and/or binders deposited on Zircar cloth were developed in order to engineer the proper capillary pressure characteristics in the separator. These asymmetric separators were prepared from a variety of fibers, particles and binders
Development of a lightweight nickel electrode
Nickel electrodes made using lightweight plastic plaque are about half the weight of electrodes made from state of the art sintered nickel plaque. This weight reduction would result in a significant improvement in the energy density of batteries using nickel electrodes (nickel hydrogen, nickel cadmium and nickel zinc). These lightweight electrodes are suitably conductive and yield comparable capacities (as high as 0.25 AH/gm (0.048 AH/sq cm)) after formation. These lightweight electrodes also show excellent discharge performance at high rates
Recent advances in Ni-H2 technology at NASA Lewis Research Center
The NASA Lewis Research Center has concentrated its efforts on advancing the Ni-H2 system technology for low Earth orbit applications. Component technology as well as the design principles were studied in an effort to understand the system behavior and failure mechanisms in order to increase performance and extend cycle life. The design principles were previously addressed. The component development is discussed, in particular the separator and nickel electrode and how these efforts will advance the Ni-H2 system technology
Electrostatics of Gapped and Finite Surface Electrodes
We present approximate methods for calculating the three-dimensional electric
potentials of finite surface electrodes including gaps between electrodes, and
estimate the effects of finite electrode thickness and an underlying dielectric
substrate. As an example we optimize a radio-frequency surface-electrode ring
ion trap, and find that each of these factors reduces the trapping secular
frequencies by less than 5% in realistic situations. This small magnitude
validates the usual assumption of neglecting the influences of gaps between
electrodes and finite electrode extent.Comment: 9 pages, 9 figures (minor changes
Experimental demonstration of a technique to generate arbitrary quantum superposition states
Using a single, harmonically trapped Be ion, we experimentally
demonstrate a technique for generation of arbitrary states of a two-level
particle confined by a harmonic potential. Rather than engineering a single
Hamiltonian that evolves the system to a desired final sate, we implement a
technique that applies a sequence of simple operations to synthesize the state
Design, Fabrication, and Experimental Demonstration of Junction Surface Ion Traps
We present the design, fabrication, and experimental implementation of
surface ion traps with Y-shaped junctions. The traps are designed to minimize
the pseudopotential variations in the junction region at the symmetric
intersection of three linear segments. We experimentally demonstrate robust
linear and junction shuttling with greater than one million round-trip shuttles
without ion loss. By minimizing the direct line of sight between trapped ions
and dielectric surfaces, negligible day-to-day and trap-to-trap variations are
observed. In addition to high-fidelity single-ion shuttling, multiple-ion
chains survive splitting, ion-position swapping, and recombining routines. The
development of two-dimensional trapping structures is an important milestone
for ion-trap quantum computing and quantum simulations.Comment: 9 pages, 6 figure
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