Abstract:
A mixture of polymeric binders that is insoluble in nonaqueous organic electrolytes activating alkali metal or alkali metal ion electrochemical cells, is described. The mixed binder formulation provides electrodes that are flexible and non-brittle, and cells incorporating the electrodes are dischargeable at elevated temperatures. The binder formulation is a mixture of halogenated polymeric material, preferably PVDF, and a polyimide which is a product of the conversion of polyamic acid.
Abstract:
A new sandwich negative electrode design for a secondary cell is provided comprising a "sacrificial" alkali metal along with a carbonaceous anode material. In the case of a hard carbon anode material, the sacrificial alkali metal is preferably lithium and is sized to compensate for the initial irreversible capacity of this anode material. Upon activating the cells, the lithium metal automatically intercalates into the hard carbon anode material. That way, the sacrificial lithium is consumed and compensates for the generally unacceptable irreversible capacity of hard carbon. The superior cycling longevity of hard carbon now provides a secondary cell of extended use beyond that know for conventional secondary cells having only graphitic anode materials.
Abstract:
A new sandwich cathode design is provided comprising a cathode active material mixed with a binder and a conductive diluent in at least two differing formulations. The formulations are then individually pressed on opposite sides of a current collector, so that both are in direct contact with the current collector. Preferably, the active formulation on the side of the current collector facing the anode is of a lesser percentage of the active material than that on the opposite side of the current collector. Such an exemplary cathode design might look like: SVO (100-x% active)/current collector/SVO (100-y% active)/current collector/SVO (100-x% active), wherein x is greater than y.
Abstract:
An alkali metal/solid cathode electrochemical cell, particularly a Li/CF x cell, having an electrolyte-to-cathode (E/C) weight ratio of about 0.938 to about 0.73, and an anode-to-cathode (A/C) capacity ratio of about 1.03, is described. This provides the cell with an improvement in terms of delivered capacity of about 6% to about 15% under a 1 kohm discharge load, and of about 2% to about 5% under a 2 kohm load in comparison to prior art Li/CF x cells. Fabricating the cathode electrode at such high pressures was not previously thought possible.
Abstract:
An electrode assembly constructed of continuous anode and cathode electrodes that are overlaid in overlapping fashion and wound into a cell stack suitable for prismatic or other non-cylindrically-shaped cases. The cathode electrode strip has some regions where the electrode material is pressed to a high density and has some regions where the active material is pressed to a lower density, such that the lower density regions correspond to the bend regions in the wound cell stack.
Abstract:
The minimization or elimination of swelling in lithium cells containing CF x as part of the cathode electrode and discharged under high rate applications is described. When CF x materials are synthesized from fibrous carbonaceous materials, in comparison to petroleum coke, cell swelling is greatly reduced, and in some cases eliminated. Preferred precursors are carbon fibers and MCMB.
Abstract:
Cobalt-based alloys are provided for use as a positive electrode current collector in a solid cathode, nonaqueous liquid electrolyte, alkali metal anode active electrochemical cell. The cobalt-based alloys are characterized by chemical compatibility with aggressive cell environments, high corrosion resistance and resistance to fluorination and passivation at elevated temperatures, thus improving the longevity and performance of the electrochemical cell. The cell can be of either a primary or a secondary configuration.
Abstract:
An electrode component for an electrochemical cell or a capacitor is described wherein the electrode is produced by physical vapor depositing an electrode active material onto a substrate to coat the substrate. The thusly produced electrode is useful as a cathode in a primary electrochemical cell and as a cathode and an anode in a secondary cell, and as an electrode in an electrochemical capacitor and an electrolytic capacitor.