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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
NASA NTRS1994

Probing the chemistry of nickel/metal hydride battery cells using electrochemical impedance spectroscopy

Electrochemical Impedance Spectroscopy (EIS) is a valuable tool for investigating the chemical and physical processes occurring at electrode surfaces. It offers information about electron transfer at interfaces, kinetics of reactions, and diffusion characteristics of the bulk phase between the electrodes. For battery cells, this technique offers another advantage in that it can be done without taking the battery apart. This non-destructive analysis technique can thus be used to gain a better understanding of the processes occurring within a battery cell. This also raises the possibility of improvements in battery design and identification or prediction of battery characteristics useful in industry and aerospace applications. EIS as a technique is powerful and capable of yielding significant information about the cell, but it also requires that the many parameters under investigation can be resolved. This implies an understanding of the processes occurring in a battery cell. Many battery types were surveyed in this work, but the main emphasis was on nickel/metal hydride batteries.

Isaac, Bryan J.↗
NASA NTRS1995

Bending properties of nickel electrodes for nickel-hydrogen batteries

Recent changes in manufacturing have resulted in nickel-hydrogen batteries which fail prematurely by electrical shorting. This is believed to be a result of a blistering problem in the nickel electrodes. This study investigates the bending properties of nickel electrodes in an attempt to correlate the bending properties with the propensity of the electrode to blister. Nickel electrodes from three different batches of material were tested in both the as-received and impregnated forms. Effects of specimen curvature and position within the electrode on the bending strength were studied and within-electrode and batch-to-batch variation were addressed. Two color imaging techniques were employed which allowed differentiation of phases within the electrodes. These techniques aided in distinguishing the relative amounts of nickel hydroxide surface loading on each electrode, relating surface loading to bend strength. Bend strength was found to increase with the amount of surface loading.

Lerch, Bradley↗
NASA NTRS1996

Bending Properties of Nickel Electrodes for Nickel-Hydrogen Batteries

Recent changes in manufacturing have resulted in nickel-hydrogen batteries that fail prematurely by electrical shorting. This failure is believed to be a result of a blistering problem in the nickel electrodes. In this study, the bending properties of nickel electrodes are investigated in an attempt to correlate the bending properties of the electrode with its propensity to blister. Nickel electrodes from three different batches of material were tested in both the as-received and impregnated forms. The effects of specimen curvature and position within the electrode on the bending strength were studied, and within-electrode and batch-to-batch variations were addressed. Bend strength was found to increase with the amount of surface loading.

Lerch, Brad A.↗
NASA NTRS1995

Bending Properties of Nickel Electrodes for Nickel-Hydrogen Batteries

Recent changes in manufacturing have resulted in nickel-hydrogen batteries that fail prematurely by electrical shorting, This failure is believed to be a result of a blistering problem in the nickel electrodes. In this study the bending properties of nickel electrodes are investigated in an attempt to correlate the bending properties of the electrode with its propensity to blister. Nickel electrodes from three different batches of material were tested in both the as-received and impregnated forms. The effects of specimen curvature and position within the electrode on the bending strength were studied, and within-electrode and batch-to-batch variations were addressed. Two color-imaging techniques were employed to differentiate between the phases within the electrodes. These techniques aided in distinguishing the relative amounts of nickel hyroxide surface loading on each electrode, thereby relating surface loading to bend strength. Bend strength was found to increase with the amount of surface loading.

Lerch, Brad A.↗
NASA NTRS1989

Novel nitrogen-based organosulfur electrodes for advanced intermediate temperature batteries

Advanced secondary batteries operating at intermediate temperatures (100 to 200 C) have attracted considerable interest due to their inherent advantages (reduced corrosion and safety risks) over higher temperature systems. Current work in this laboratory has involved research on a class of intermediate temperature Na/beta double prime- alumina/RSSR batteries conceptually similar to Na/S cells, but operating within a temperature range of 100 to 150 C, and having an organosulfur rather than inorganic sulfur positive electrode. The organosulfur electrodes are based on the reversible, two electron eduction of organodisulfides to the corresponding thiolate anions, RSSR + 2 electrons yield 2RS(-), where R is an organic moiety. Among the advantages of such a generic redox couple for battery research is the ability to tailor the physical, chemical, and electrochemical properties of the RSSR molecule through choice of the organic moiety. The viscosity, liquidus range, dielectric constant, equivalent weight, and redox potential can in fact be verified in a largely predictable manner. The current work concerns the use of multiple nitrogen organosulfur molecules, chosen for application in Na/RSSR cells for their expected oxidizing character. In fact, a Na/RSSR cell containing one of these materials, the sodium salt of 5-mercapto 1-methyltetrazole, yielded the highest open circuit voltage obtained yet in the laboratory; 3.0 volts in the charged state and 2.6 volts at 100 percent discharge. Accordingly, the cycling behavior of a series of multiple nitrogen organodisulfides as well as polymeric organodisulfides are presented in this manuscript.

Visco, S. J.↗
NASA NTRS1991

Effect of sinter fracture and ohmic resistance on capacity retention in the nickel oxide electrode

The lifetime of batteries which utilize the nickel oxide electrode is often limited because this electrode loses a significant portion of its capacity as it is cycled. It is asserted that this capacity loss may often be attributed to cracking or separation of the conductive nickel sinter in the electrode, which forces electronic current to pass through the poorly conducting hydrated oxide and thus imposes a significant ohmic resistance. The model indicates that the oxide develops a nearly insulating layer which prevents complete discharge in the cycled electrode at usable rates. The capacity retention can be improved by reducing the cyclic stresses or strengthening the current collecting structure, redistributing it to provide a shorter current path through the solid phase, or by increasing the conductivity of the oxide to delay the formation of an insulating layer.

Lanzi, Oscar↗
NASA NTRS2003

In-SITU Raman Spectroscopy of Single Microparticle Li-Intercalation Electrodes

Modifications in the vibrational properties of a single microparticle of LiMn2O4 induced by extraction and subsequent injection of Li(+) into the lattice have been monitored in situ via simultaneous acquisition of Raman scattering spectra and cyclic voltammetry data in 1M LiC1O4 solutions in ethylene carbonate (EC):diethyl carbonate (DEC) mixtures (1:1 by volume). Statistical analyses of the spectra in the range 15 < SOD < 45%, where SOD represents the state of discharge (in percent) of the nominally fully charged material, i.e. lambda-MnO2, were found to be consistent with the coexistence of two distinct phases of lithiated metal oxide in agreement with information derived from in situ X-ray diffraction (XRD) measurements involving more conventional battery-type electrodes.

Dokko, Kaoru↗
NASA NTRS1979

Further development and application of polycrystalline metal whiskers

High strength metal whiskers have a larger versatile field of application than monocrystalline whiskers. Although polycrystalline metal whiskers can be used for composites, preferably by extrusion in thermoplastics or by infiltration of resins or metals into whisker networks, the chief application at present may be the production and various use of whisker networks. Such networks can be produced up to high degrees of porosity and besides high mechanical strength, they have high inside surfaces and high electric conductivity. There are for instance, applications concerning construction of electrodes for batteries and fuel cells, catalysts and also new heat-exchanger material, capable of preparing fuel oil and gasoline in order to assist a high-efficiency combustion. The technical application of polycrystalline metal whiskers require their modification as well as the construction of a pilot production unit.

Schladitz, H. J.↗
NASA NTRS1987

Advanced hydrogen electrode for hydrogen-bromide battery

Binary platinum alloys are being developed as hydrogen electrocatalysts for use in a hydrogen bromide battery system. These alloys were varied in terms of alloy component mole ratio and heat treatment temperature. Electrocatalyst evaluation, performed in the absence and presence of bromide ion, includes floating half cell polarization studies, electrochemical surface area measurements, X ray diffraction analysis, scanning electron microscopy analysis and corrosion measurements. Results obtained to date indicate a platinum rich alloy has the best tolerance to bromide ion poisoning.

Kosek, Jack A.↗
NASA NTRS2000

Electrolyte and Electrode Passivation for Thin Film Batteries

Passivation films for thin film batteries have been prepared and the conductivity and voltage stability window have been measured. Thin films of Li2CO3 have a large voltage stability window of 4.8V, which facilitates the use of this film as a passivation at both the lithium anode-electrolyte interface at high cathodic potentials.

passivation thin film batteries↗
NASA NTRS1996

Application of First Principles Model to Spacecraft Operations

Previous models use a single phase reaction; cycled cell predicts cannot be met with a single phase; interphase conversion provides means for film aging; aging cells predictions display typical behaviors: pressure changes in NiH&sup2; cells; voltage fading upon cycling; second plateau on discharge of cycled cells; negative limited behavior for Ni-Cds.

batteries electrodes First Principles Model Ni-Cd ↗