Electrolyte additive for improved battery performance
First Claim
1. An electrochemical cell having a metal bromine couple, said cell comprising:
- an electrode structure on which the metal of the couple is deposited during charging of the cell;
a counterelectrode structure at which to generate cathodic bromine during charging of the cell;
a microporous separator between said electrode and counterelectrode structure;
an aqueous electrolyte of a metal bromide, the metal of the bromide being the same as the metal of the couple and including a water soluble complexing agent capable of forming a water immiscible complex with bromine; and
an additive capable of decreasing the wettability of the microporous separator by the immiscible bromine complex formed during charging of the cell, said additive being present in amount sufficient to produce a measurable increase in the coulombic efficiency of said cell.
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Accused Products
Abstract
In one embodiment of the present invention, there is provided an electrochemical cell having a metal bromine couple. The cell includes an electrode structure on which to deposit the metal of the couple and a counterelectrode at which to generate bromine. A microporous membrane separates the electrode and counterelectrode. Importantly, the aqueous electrolyte comprises an aqueous metal bromide solution containing a water soluble bromine complexing agent capable of forming a water immiscible complex with bromine and an additive capable of decreasing the wettability of the microporous separators employed in such cells by such water immiscible bromine complexes.
16 Citations
10 Claims
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1. An electrochemical cell having a metal bromine couple, said cell comprising:
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an electrode structure on which the metal of the couple is deposited during charging of the cell; a counterelectrode structure at which to generate cathodic bromine during charging of the cell; a microporous separator between said electrode and counterelectrode structure; an aqueous electrolyte of a metal bromide, the metal of the bromide being the same as the metal of the couple and including a water soluble complexing agent capable of forming a water immiscible complex with bromine; and an additive capable of decreasing the wettability of the microporous separator by the immiscible bromine complex formed during charging of the cell, said additive being present in amount sufficient to produce a measurable increase in the coulombic efficiency of said cell. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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- 8. A method of enhancing coulombic efficiency of electrochemical zinc or cadmium bromine cells having microporous separators and employing aqueous zinc bromide or cadmium bromide electrolyte and a water soluble complexing agent capable of forming a water immiscible complex with bromine, said method comprising adding an additive to said electrolyte which is capable of decreasing the wettability of said microporous separator by said water immiscible bromine complex wherein the coulombic efficiency of said cell is increased.
Specification