655 research outputs found
Silicon containing electroconductive polymers and structures made therefrom
An electropolymerized film comprised of polymers and copolymers of a monomer is formed on the surface of an anode. The finished structures have superior electrical and mechanical properties for use in applications such as electrostatic dissipation and for the reduction of the radar cross section of advanced aircraft
Secondary Li battery incorporating 12-Crown-4 ether
A rechargeable lithium battery which utilizes a polyethylene oxide (PEO) solid polymeric electrolyte complexed with a lithium salt is disclosed. The conductivity is increased an order of magnitude and interfacial charge transfer resistance is substantially decreased by incorporating a minor amount of 12-Crown-4 ether in the PEO-lithium salt solid electrolyte film. Batteries containing the improved electrolyte permit operation at a lower temperature with improved efficiency
Copper chloride cathode for a secondary battery
Higher energy and power densities are achieved in a secondary battery based on molten sodium and a solid, ceramic separator such as a beta alumina and a molten catholyte such as sodium tetrachloroaluminate and a copper chloride cathode. The higher cell voltage of copper chloride provides higher energy densities and the higher power density results from increased conductivity resulting from formation of copper as discharge proceeds
Method for forming thin composite solid electrolyte film for lithium batteries
A composite solid electrolyte film is formed by dissolving a lithium salt such as lithium iodide in a mixture of a first solvent which is a cosolvent for the lithium salt and a binder polymer such as polyethylene oxide and a second solvent which is a solvent for the binder polymer and has poor solubility for the lithium salt. Reinforcing filler such as alumina particles are then added to form a suspension followed by the slow addition of binder polymer. The binder polymer does not agglomerate the alumina particles. The suspension is cast into a uniform film
Reversible non-volatile switch based on a TCNQ charge transfer complex
A solid-state synaptic memory matrix (10) having switchable weakly conductive connections at each node (24) whose resistances can be selectably increased or decreased over several orders of magnitude by control signals of opposite polarity, and which will remain stable after the signals are removed, comprises an insulated substrate (16), a set of electrical conductors (14) upon which is deposited a layer (18) of an organic conducting polymer, which changes from an insulator to a conductor upon the transfer of electrons, such as polymerized pyrrole doped with 7,7,8,8-tetracyanoquinodimethane (TCNQ), covered by a second set of conductors (20) laid at right angles to the first
Episcleral Venous Pressure and the Ocular Hypotensive Effects of Topical and Intracameral Prostaglandin Analogs.
There is a limit beyond which increasing either the concentration of a prostaglandin analog (PGA) or its dosing frequency fails to produce increases in ocular hypotensive efficacy with topical dosing. Intracameral PGA dosing with a bimatoprost implant, however, does not exhibit the same intraocular pressure (IOP)-lowering plateau at studied concentrations, and the maximum-achievable ocular hypotensive effects are not yet known. This suggests that the bimatoprost intracameral implant may activate another mechanism of action in addition to the mechanism(s) activated by topical application. Episcleral venous pressure (EVP) is a key determinant of IOP, and experimental manipulation of the episcleral vasculature can change both EVP and IOP. The recent observation that topical and intracameral PGA drug delivery routes produce different patterns of conjunctival hyperemia suggested that the differences in the IOP-lowering profiles may be caused by differing effects on the episcleral vasculature. Recent experiments in animals have shown that topical PGAs increase EVP, while the bimatoprost intracameral implant causes a smaller, transient increase in EVP, followed by a sustained decrease. The increase in EVP could be limiting the IOP-lowering efficacy of topical PGAs. In contrast, the decrease in EVP associated with the bimatoprost implant could explain its enhanced IOP-lowering effects. Further research on EVP as a target for IOP lowering is indicated to improve our understanding of this potentially important pathway for treating patients with glaucoma
Method for forming thin composite solid electrolyte film for lithium batteries
A composite solid electrolyte film is formed by dissolving a lithium salt such as lithium iodide in a mixture of a first solvent which is a co-solvent for the lithium salt and a binder polymer such as polyethylene oxide and a second solvent which is a solvent for the binder polymer and has poor solubility for the lithium salt. Reinforcing filler such as alumina particles are then added to form a suspension followed by the slow addition of binder polymer. The binder polymer does not agglomerate the alumina particles. The suspension is cast into a uniform film
Understanding the limits of rapid charging using instrumented commercial 18650 high-energy Li-ion cells
The charging rates of commercial high-energy Li-ion cells are limited by the manufacturer's specifications leading to lengthy charging times. However, these cells are typically capable of much faster charging, if one ensures that the thermal and electrode-specific voltage profiles do not exceed safety limits. Unfortunately, precise and in-situ measurements of these parameters have not been achieved to date without altering the operation of these cells. Here we present a method to assess the maximum current for commercial 18650s, using novel instrumentation methods enabling in operando measurements. We found the maximum charging current that could be safely applied to the evaluated high-energy cells is 6.7 times higher than the manufacturer-stated maximum. Subsequently a rapid-charging protocol was developed that leads to over five-fold reduction in charging times without compromising the safety limits of the cells. We anticipate our work to be a starting point for a more sophisticated understanding of commercial Li-ion cells through deployment of diverse in-situ sensor systems. This understanding will enable advances in battery materials science, thermal engineering and electrical engineering of battery technology. Furthermore, this work has the potential to help the design of energy storage systems for high performance applications such as motor racing and grid balancing
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Improved power source for doubling the exchange time interval of LLC.
This LDRD project attempts to use novel electrochemical techniques to understand the reaction mechanism that limits the discharge reaction of lithium CF{sub x} chemistry. If this advanced component development and exploratory investigations efforts are successful we will have a High Energy Density Li Primary Battery Technology with the capability to double the run time in the same volume, or provide the same energy in a much smaller volume. These achievements would be a substantial improvement over commercial Li/Thionyl chloride battery technology. The Li(CF{sub x}){sub n} chemistry has the highest theoretical energy (and capacity) and hence very attractive for long life battery applications. However, the practical open circuit voltage (OCV) is only 3.2 V which is {approx}1.3 V lower than the thermodynamic cell voltage (for an in depth explanation of the voltage depression refer to 'Introduction'). The presence of intermediate has been invoked to explain the lower OCV of the cell. Due to the reduction in cell voltage the cell out put is reduced by {approx}40%. To account for the initial voltage loss a mechanism has been proposed which involves the formation of a ternary compound (like C(LiF){sub x}). But neither its presence nor its nature has been confirmed. Our work will seek to develop understanding of the voltage depression with a goal to produce a primary battery with improved properties that will have significant impact in furthering advancements
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