Electrolytes for rechargeable electrochemical cells

Abstract

The present invention relates to an electrolyte for use in a rechargeable electrochemical cell. One aspect of the present invention provides an electrolyte for use in a bipolar static secondary zinc-bromine electrochemical cell, comprising 25 wt % to 70 wt % ZnBr 2 , 5 to 50 wt% water, 0.5 to 5 wt% C 2‑10 diol and 0.05 to 10 weight percent of one or more quaternary ammonium agents.

Description

[0001] This application is a divisional application of an invention patent application with an application date of March 29, 2017, application number “201780029813.5”, and name “Electrolyte for Rechargeable Electrochemical Cells”.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This PCT application claims the benefit of U.S. Application No. 15 / 083,558, filed on March 29, 2016. The disclosure is incorporated herein by reference in its entirety. Technical Field

[0004] The present invention relates to electrolytes that can be used in zinc halide rechargeable electrochemical cells (e.g., energy storage batteries). More specifically, the present invention relates to aqueous electrolytes that reversibly electrolyze zinc halides in electrochemical energy storage cells or batteries. Background Art

[0005] Zinc-halide batteries have been developed as a means of storing electrical energy. Conventional zinc-halide batteries (e.g., zinc-bromine batteries) employ bipolar electrodes disposed in a static (i.e., non-flowing) aqueous zinc bromide solution. The process of charging and discharging current in zinc-halide batteries is generally accomplished by the transfer of a charge or discharge current from a zinc halide electrolyte such as Zn 2+ / Zn(s) and X - / X2, wherein X is a halogen (e.g., Cl, Br or I).

[0006] When an electric current is applied to a battery, the following chemical reactions occur:

[0007] Zn 2+ +2e - →Zn

[0008] 2X - →X2+2e - .

[0009] Conversely, when the battery discharges current, the following chemical reactions occur:

[0010] Zn→Zn 2+ +2e -

[0011] X2+2e - →2X - .

[0012] Additionally, in some batteries, polyhalide reactions may also occur. Some of these examples are described below:

[0013] or

[0014] For n≥3.

[0015] The polyhalide reactions shown above can include reactions between the same halogen (e.g., Br3), as well as reactions between different halogens, such as mixed halogens, such as Br2Cl.

[0016] These zinc-halogen energy storage batteries are usually configured in a bipolar electrochemical battery, where each electrode is disposed in an aqueous zinc salt electrolyte. However, the performance of these energy storage batteries is highly inefficient due to side reactions of species dissolved in the aqueous electrolyte. For example, in solution, elemental bromine exists as bromide ions in equilibrium to form polybromide ions, Where m = 3, 5, or 7. Side hydrolysis reactions are also problematic for these types of energy storage batteries when the electrolyte is formulated with excess free water because bromate solids form, which in turn reduces the amount of available bromide / bromine in the electrochemical cell that can be reduced or oxidized.

[0017]

[0018] Elemental bromine also has an increased vapor pressure, which increases harmful pressures in the battery. In addition, when aqueous zinc halide salts are ionized, zinc ions can exist as various complex ions and ion pairs, which promote the formation of zinc dendrites and increase the incidence of self-discharge in the battery. In order to improve the durability of the electrolyte in the battery, halogen separators (e.g., quaternary ammonium salts or heteroaryl salts (e.g., pyridinium salts)) are added; however, these separators generally have reduced solubility after multiple charging cycles and reduce the stability of the electrolyte. Summary of the invention

[0019] The present invention provides an aqueous electrolyte for use in a rechargeable zinc-halogen energy storage battery having improved stability and durability and improved zinc-halogen battery performance. In one aspect, the electrolyte comprises about 25 wt % to about 70 wt % ZnBr2, about 5 wt % to about 50 wt % water, and one or more quaternary ammonium agents, wherein the electrolyte comprises about 0.05 wt % to about 10 wt % of the one or more quaternary ammonium agents.

[0020] In some embodiments, the electrolyte further comprises at least one alkaline halide salt selected from NaCl, NaBr, LiCl, LiBr, RbCl, RbBr, KCl, KBr, and the total concentration of the alkaline halide salt is about 2 wt % to about 35 wt % based on the weight of the electrolyte. For example, the electrolyte further comprises about 1 wt % to about 15 wt % KBr, and about 5 wt % to about 20 wt % KCl.

[0021] In some embodiments, the electrolyte comprises about 27 wt % to about 40 wt % ZnBr 2. For example, the electrolyte comprises about 28 wt % to about 37 wt % ZnBr 2.

[0022] In some embodiments, the electrolyte comprises from about 1.5 wt % to about 7.5 wt % ZnCl 2 .

[0023] And, in some embodiments, the electrolyte comprises about 30 wt % to about 45 wt % water. For example, the electrolyte comprises about 35 wt % to about 41 wt % water.

[0024] In alternative embodiments, the electrolyte comprises about 2 wt % to about 10 wt % KBr. For example, the electrolyte comprises about 7.3 wt % to about 9.2 wt % KBr.

[0025] And, in some embodiments, the electrolyte includes about 7 wt % to about 17 wt % KCl.

[0026] In some embodiments, the electrolyte comprises about 0.5 wt % to about 10 wt % of glyme. Also, in some embodiments, the glyme comprises monoglyme, diglyme, triglyme, tetraglyme, pentaglyme, hexaglyme, or any combination thereof. For example, the electrolyte comprises about 2 wt % to about 4 wt % of tetraglyme.

[0027] In some embodiments, the electrolyte comprises about 0.5 wt % to about 2.5 wt %, selected from the ether of DME-PEG, dimethyl ether or any combination thereof. For example, the electrolyte comprises DME-PEG, and DME-PEG has an average molecular weight of about 350amu to about 3000amu. In other examples, DME-PEG has an average molecular weight of about 1200amu to about 3000amu. And, in some embodiments, DME-PEG is DME-PEG 2000, DME-PEG 1000, or a combination thereof. In other examples, the electrolyte comprises about 1 wt % to about 2 wt % of DME-PEG 2000. And, in some examples, the electrolyte comprises about 0.25 wt % to about 0.75 wt % of DME-PEG 1000. For example, the electrolyte comprises about 1 wt % to about 2 wt % of DME-PEG 2000 and about 0.25 wt % to about 0.75 wt % of DME-PEG 1000.

[0028] In some embodiments, the electrolyte further comprises about 0.1 wt % to about 1.0 wt % of an alcohol, wherein the alcohol is substantially miscible in water. For example, the alcohol comprises C 1-4Alcohol. In other examples, the alcohol includes methanol, ethanol, 1-propanol, isopropanol, 1-butanol, sec-butanol, isobutanol, tert-butanol, or any combination thereof. For example, the electrolyte includes about 0.25 wt % to about 0.75 wt % tert-butanol.

[0029] In some embodiments, the electrolyte comprises about 0.5 wt % to about 5 wt % C 1-10 In some examples, the diol includes ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, hexylene glycol, or any combination thereof. Also, in some embodiments, the electrolyte includes about 0.25 wt % to about 2.5 wt % neopentyl glycol.

[0030] In some embodiments, the electrolyte further comprises about 0.05 wt % to about 20 wt % of one or more quaternary ammonium agents. And, in some examples, the one or more quaternary ammonium agents include a quaternary ammonium agent selected from the group consisting of ammonium, tetraethylammonium, trimethylpropylammonium, N-methyl-N-ethylmorpholine (MEM), N-ethyl-N-methylmorpholine, N-methyl-N-butylmorpholine, N-methyl-N-ethylpyrrolidinium, N,N,N-triethyl-N-propylammonium, N-ethyl-N-propylpyrrolidinium, N-propyl-N-butylpyrrolidinium, N-methyl-N-butylpyrrolidinium, 1-methyl-1-butylpyrrolidinium, N-ethyl-N-(2-chloroethyl)pyrrolidinium, N- Methyl-N-hexylpyrrolidinium, N-methyl-N-pentylpyrrolidinium, N-ethyl-N-pentylpyrrolidinium, N-ethyl-N-butylpyrrolidinium, trimethyl-bis(N-methylpyrrolidinium), N-butyl-N-pentylpyrrolidinium, N-methyl-N-propylpyrrolidinium, N-propyl-N-pentylpyrrolidinium, 1-ethyl-4-methylpyridinium, 1-ethyl-3-methylpyridinium, 1-ethyl-2-methylpyridinium, 1-butyl-3-methylpyridinium, hexadecyltrimethylammonium, triethylmethylammonium chloride or bromide, and any combination thereof. In some examples, the quaternary ammonium agent includes 1-ethyl-4-methylpyridinium, 1-ethyl-2-methylpyridinium, 1-ethyl-3-methylpyridinium, triethylmethylammonium, triethylmethylammonium, 1,1'-dioctadecyl-4-4'-bipyridinium chloride or bromide, or any combination thereof. In some examples, the one or more quaternary ammonium agents include quaternary ammonium agents selected from the following: ammonium, tetraethylammonium, trimethylpropylammonium, N-methyl-N-ethylmorpholine (MEM), 1-ethyl-1-methylmorpholine, N-methyl-N-ethylpyrrolidinium, 1-methyl-1-butylpyrrolidinium, 1-ethyl-4-methylpyridinium, 1-ethyl-2-methylpyridinium, 1-butyl-3-methylpyridinium, hexadecyltrimethylammonium, triethylmethylammonium chloride or bromide, and any combination thereof.

[0031] In some embodiments, the electrolyte further comprises about 0.05 wt % to about 20 wt % of one or more quaternary ammonium agents, and the one or more quaternary ammonium agents include a quaternary ammonium agent selected from the group consisting of ammonium bromide, ammonium chloride, tetraethylammonium bromide, trimethylpropylammonium bromide, N-methyl-N-ethylmorpholinium bromide, N-methyl-N-ethylmorpholinium bromide (MEMBr), N-methyl-N-butylmorpholinium bromide, N-methyl-N-ethylpyrrolidinium bromide, N,N,N-triethyl-N-propylammonium bromide, N-ethyl-N-propylpyrrolidinium bromide, N-propyl-N-butylpyrrolidinium bromide, N-methyl-N-butylpyrrolidinium bromide, 1-methyl-1-butylpyrrolidinium bromide, bromide, N-ethyl-N-(2-chloroethyl)pyrrolidinium bromide, N-methyl-N-hexylpyrrolidinium bromide, N-methyl-N-pentylpyrrolidinium bromide, N-ethyl-N-pentylpyrrolidinium bromide, N-ethyl-N-butylpyrrolidinium bromide, trimethyl-bis(N-methylpyrrolidinium) dibromide, N-butyl-N-pentylpyrrolidinium bromide, N-methyl-N-propylpyrrolidinium bromide, N-propyl-N-pentylpyrrolidinium bromide, 1-ethyl-4-methylpyridinium bromide, 1-ethyl-2-methylpyridinium bromide, 1-butyl-3-methylpyridinium bromide, hexadecyltrimethylammonium bromide, triethylmethylammonium bromide, and any combination thereof. In some examples, the quaternary ammonium agent includes at least one of 1-ethyl-4-methylpyridinium bromide, 1-ethyl-2-methylpyridinium bromide, triethylmethylammonium bromide, triethylmethylammonium chloride, 1,1′-dioctadecyl-4-4′-bipyridinium dibromide, or 1-ethyl-4-methylpyridinium bromide. In some examples, the one or more quaternary ammonium agents include a quaternary ammonium agent selected from the group consisting of ammonium chloride, tetraethylammonium bromide, trimethylpropylammonium bromide, N-methyl-N-ethylmorpholinium bromide (MEMBr), N-methyl-N-ethylpyrrolidinium bromide, 1-methyl-1-butylpyrrolidinium bromide, 1-ethyl-4-methylpyridinium bromide, 1-ethyl-2-methylpyridinium bromide, 1-butyl-3-methylpyridinium bromide, hexadecyltrimethylammonium bromide, decyltrimethylammonium bromide, tridecyltrimethylammonium bromide, or any combination thereof.

[0032] In some embodiments, the one or more quaternary ammonium agents include at least one agent selected from 1-ethyl-2-methylpyridinium bromide, 1-ethyl-3-methylpyridinium bromide, or 1-ethyl-4-methylpyridinium bromide.

[0033] In some embodiments, the one or more quaternary ammonium agents include 1-ethyl-2-methylpyridinium bromide, 1-ethyl-3-methylpyridinium bromide or 1-ethyl-4-methylpyridinium bromide at about 3.5% to about 4.5% by weight of the weight of the electrolyte. In some embodiments, the one or more quaternary ammonium agents include 1-ethyl-2-methylpyridinium bromide at about 1% to about 7% by weight of the weight of the electrolyte. In some embodiments, the one or more quaternary ammonium agents include 1-methyl-1-butylpyrrolidinium bromide at about 1.5% to about 2.5% by weight of the weight of the electrolyte. In some embodiments, the one or more quaternary ammonium agents include 1-butyl-3-methylpyridinium bromide at about 1.5% to about 2.5% by weight of the weight of the electrolyte. In some embodiments, the one or more quaternary ammonium agents include 1-methyl-1-ethylmorpholine bromide at about 1.5% to about 5% by weight of the weight of the electrolyte. In some embodiments, the one or more quaternary ammonium agents include about 0.5% to about 1.5% by weight of N-methyl-N-ethylmorpholinium bromide (MEMBr) by weight of the electrolyte. In some embodiments, the one or more quaternary ammonium agents include about 14.5% to about 16.5% by weight of N-methyl-N-ethylpyrrolidinium bromide by weight of the electrolyte. In some embodiments, the one or more quaternary ammonium agents include about 2% to about 3% by weight of trimethylpropylammonium bromide by weight of the electrolyte. In some embodiments, the one or more quaternary ammonium agents include about 2% to about 8% by weight of tetraethylammonium bromide by weight of the electrolyte. In some embodiments, the one or more quaternary ammonium agents include about 0.05% to about 0.2% by weight of hexadecyltrimethylammonium bromide by weight of the electrolyte.

[0034] And, in other embodiments, the electrolyte comprises less than 1 wt % by weight of the electrolyte, one or more additives selected from Sn, In, Ga, Al, Tl, Bi, Pb, Sb, Ag, Mn or Fe. For example, the one or more additives are selected from about 0.0008 wt % to about 0.0012 wt % Sn (e.g., provided as SnCl2 or any hydrate thereof), about 0.0008 wt % to about 0.0012 wt % In (e.g., provided as InCl3 or any hydrate thereof), and combinations thereof.

[0035] In some embodiments, the electrolyte comprises an acid or a conjugate base of an acid selected from acetic acid, nitric acid, hydrobromic acid, and citric acid. For example, the electrolyte comprises acetic acid, sodium acetate, or potassium acetate at about 0.3% to about 0.6% by weight of the electrolyte. In another example, the electrolyte comprises nitric acid at about 0.12% to about 0.08% by weight of the electrolyte. And, in some examples, the electrolyte comprises citric acid at about 3.5% to about 4.5% by weight of the electrolyte. In an alternative example, the electrolyte comprises potassium dihydrogen citrate at about 3.5% to about 4.5% by weight of the electrolyte.

[0036] In other embodiments, the electrolyte comprises about 0.05 wt % to about 0.75 wt % of a crown ether (e.g., 18 crown 6, 15 crown 5, 12 crown 4, or any combination thereof) based on the weight of the electrolyte. In some embodiments, the choice of crown depends on the cations formed by the dissolution of the alkaline halide salt in the electrolyte. For example, wherein one or more of the alkaline halide salts generates Li in the electrolyte + cation, the electrolyte comprising about 0.05 wt % to about 0.75 wt % of 12 crown 4 ether. In another example, one or more of the alkaline halide salts generates Na in the electrolyte. + cation, the electrolyte comprising about 0.05 wt % to about 0.75 wt % of 15 crown 5 ether. And, in some examples, one or more of the alkaline halide salts generates K in the electrolyte. + The electrolyte comprises about 0.05 wt % to about 0.75 wt % of 18-crown-6 ether, based on the weight of the electrolyte. In some examples, the electrolyte comprises about 0.15 wt % to about 0.5 wt % of 18-crown-6, based on the weight of the electrolyte. In other examples, the electrolyte comprises about 0.05 wt % to about 0.2 wt % of 15-crown-5, based on the weight of the electrolyte.

[0037] Another aspect of the present invention provides an electrolyte for use in a secondary zinc-halide electrochemical cell, comprising, by weight of the electrolyte, from about 27 wt % to about 40 wt % ZnBr2, from about 35 wt % to about 41 wt % water, from about 7.3 wt % to about 9.2 wt % KBr, from about 7 wt % to about 17 wt % KCl, from about 0.3 wt % to about 0.6 wt % acetic acid, and from about 2 wt % to about 8 wt % tetraethylammonium bromide, wherein these weight percentages are by weight of the electrolyte.

[0038] Another aspect of the present invention provides an electrolyte for use in a secondary zinc-halogen electrochemical cell, comprising from about 27 wt % to about 40 wt % ZnBr2, and from about 1 wt % to about 10 wt % 1-ethyl-4-methylpyridinium bromide or from about 1 wt % to about 7 wt % 1-ethyl-2-methylpyridinium bromide, based on the weight of the electrolyte.

[0039] Another aspect of the present invention provides an electrolyte for use in a secondary zinc-halogen electrochemical cell, comprising from about 27 wt % to about 40 wt % ZnBr2, and from about 5 ppm to about 15 ppm In, Sn, or both, based on the weight of the electrolyte. In some embodiments, the electrolyte further comprises 1-ethyl-4-methylpyridinium bromide.

[0040] In some embodiments, the electrolyte further comprises from about 0.05 wt % to about 0.2 wt % cetyltrimethylammonium bromide (CTAB), based on the weight of the electrolyte.

[0041] In some embodiments, the electrolyte comprises from about 3.5 wt % to about 4.5 wt % citric acid monohydrate, based on the weight of the electrolyte.

[0042] In some embodiments, the electrolyte comprises from about 3.5 wt % to about 4.5 wt % potassium dihydrogen citrate monohydrate, based on the weight of the electrolyte.

[0043] Another aspect of the present invention provides an electrolyte for use in a secondary zinc-halide electrochemical cell, comprising, by weight of the electrolyte, from about 27 wt % to about 40 wt % ZnBr2, from about 35 wt % to about 41 wt % water, from about 7.3 wt % to about 9.2 wt % KBr, from about 7 wt % to about 17 wt % KCl, from about 0.15 wt % to about 0.5 wt % 18-crown-6, and from about 0.05 wt % to about 0.2 wt % cetyltrimethylammonium bromide, wherein the weight percentages are by weight of the electrolyte.

[0044] In some embodiments, the electrolyte comprises from about 2 wt % to about 8 wt % tetraethylammonium bromide, based on the weight of the electrolyte.

[0045] In some embodiments, the electrolyte comprises about 0.3 wt % to about 0.6 wt % acetic acid, based on the weight of the electrolyte. In some examples, the electrolyte comprises about 0.3 wt % to about 0.6 wt % HBr, based on the weight of the electrolyte.

[0046] In some embodiments, the electrolyte comprises about 1 wt % to about 2 wt % DME-PEG 2000 (MPEG2K). In some embodiments, the electrolyte comprises about 0.25 wt % to about 0.75 wt % DME-PEG 1000 (MPEG 1K). In other embodiments, the electrolyte comprises about 1 wt % to about 2 wt % DME-PEG 2000 (MPEG 2K) and about 0.25 wt % to about 0.75 wt % DME-PEG 1000 (MPEG 1K).

[0047] Another aspect of the present invention provides a method for preparing an electrolyte for use in a secondary zinc-halogen electrochemical cell, comprising mixing ZnBr2, KBr, KCl, and one or more quaternary ammonium agents under aqueous conditions to form a mixture and stirring the mixture until solids have dissolved or are evenly distributed throughout the mixture, wherein the mixture comprises about 27 wt % to about 40 wt % ZnBr2, about 7.3 wt % to about 9.2 wt % KBr, about 7 wt % to about 17 wt % KCl, about 0.05 wt % to about 20 wt % of one or more quaternary ammonium agents, and about 35 wt % to about 41 wt % water.

[0048] Another aspect of the present invention provides an electrolyte for use in a secondary static zinc-halogen electrochemical cell comprising one or more quaternary ammonium agents at a polymeric concentration of about 2.0 wt % to about 15.0 wt %, wherein the one or more quaternary ammonium agents comprises at least cetyltrimethylammonium chloride or cetyltrimethylammonium bromide.

[0049] In some embodiments, the electrolyte further comprises about 0.2 wt % to about 1.2 wt % of hexadecyltrimethylammonium chloride or hexadecyltrimethylammonium bromide, and at least one additional quaternary ammonium agent. For example, the electrolyte additionally comprises alkyl-substituted pyridinium chloride or alkyl-substituted pyridinium bromide. In some instances, the electrolyte comprises about 1.8 wt % to about 7.5 wt % of alkyl-substituted pyridinium chloride or alkyl-substituted pyridinium bromide. In other instances, the electrolyte comprises about 2.0 wt % to about 6.0 wt % of alkyl-substituted pyridinium chloride or alkyl-substituted pyridinium bromide. For example, the electrolyte comprises about 2.0 wt % to about 6.0 wt % of alkyl-substituted pyridinium bromide, wherein the alkyl-substituted pyridinium bromide is selected from 1-ethyl-2-methylpyridinium bromide, 1-ethyl-3-methylpyridinium bromide or 1-ethyl-4-methylpyridinium bromide.

[0050] In some embodiments, the electrolyte includes about 0.05 wt % to about 0.2 wt % of 1,1'-dioctadecyl-4-4'-bipyridinium chloride or about 0.05 wt % to about 0.2 wt % of 1,1'-dioctadecyl-4-4'-bipyridinium bromide.

[0051] In some embodiments, the electrolyte further comprises about 25 wt % to about 40 wt % ZnBr2. In some embodiments, the additional electrolyte comprises about 25 wt % to about 45 wt % water. In some embodiments, the electrolyte further comprises about 1 wt % to about 5 wt % KBr. And, in some embodiments, the electrolyte further comprises about 5 wt % to about 15 wt % KCl.

[0052] In certain embodiments, electrolyte comprises about 0.5 wt % to about 2.5 wt %, selected from the ether of DME-PEG, dimethyl ether or any combination thereof. In some instances, ether is DME-PEG, and DME-PEG has a mean molecular weight of about 350amu to about 3000amu. For example, DME-PEG has a mean molecular weight of about 750amu to about 2500amu. In certain embodiments, ether is DME-PEG, and electrolyte comprises about 0.1 wt % to about 0.5 wt % DME-PEG, and the DME-PEG has a mean molecular weight of about 750amu to about 1250amu. In certain embodiments, ether is DME-PEG, and electrolyte comprises about 1.0 wt % to about 2.0 wt % DME-PEG, and the DME-PEG has a mean molecular weight of 1750amu to about 2250amu.

[0053] In some embodiments, the electrolyte further comprises about 2 wt % to about 6 wt % of tetraethylammonium chloride or tetraethylammonium bromide. For example, the electrolyte comprises about 2 wt % to about 6 wt % of tetraethylammonium bromide.

[0054] In some embodiments, the electrolyte further comprises N-ethyl-N-methylmorpholinium chloride or N-ethyl-N-methylmorpholinium bromide. For example, the electrolyte comprises about 0.5 wt % to about 2.0 wt % of N-ethyl-N-methylmorpholinium chloride or N-ethyl-N-methylmorpholinium bromide.

[0055] Another aspect of the present invention provides an electrolyte for use in a secondary zinc-bromine electrochemical cell, comprising about 25 wt % to about 40 wt % ZnBr2, about 25 wt % to about 45 wt % water, and one or more quaternary ammonium agents, wherein the electrolyte has a polymeric concentration of the one or more quaternary ammonium agents from about 2.0 wt % to about 15.0 wt %, and wherein the one or more quaternary ammonium agents comprise at least hexadecyltrimethylammonium bromide, and an alkyl-substituted pyridinium bromide, wherein the alkyl-substituted pyridinium bromide is selected from 1-ethyl-2-methylpyridinium bromide, 1-ethyl-3-methylpyridinium bromide, or 1-ethyl-4-methylpyridinium bromide.

[0056] In some embodiments, the electrolyte further comprises from about 0.2 wt % to about 1.2 wt % of cetyltrimethylammonium bromide and from about 1.8 wt % to about 7.5 wt % of an alkyl-substituted pyridinium bromide.

[0057] In some embodiments, the electrolyte further comprises about 0.05 wt % to about 0.2 wt % of 1,1'-dioctadecyl-4-4'-bipyridinium chloride or about 0.05 wt % to about 0.2 wt % of 1,1'-dioctadecyl-4-4'-bipyridinium bromide.

[0058] In some embodiments, the electrolyte further comprises from about 1 wt % to about 5 wt % KBr. In some embodiments, the electrolyte further comprises from about 5 wt % to about 15 wt % KCl.

[0059] Another aspect of the present invention provides an electrolyte for use in a secondary zinc-bromine electrochemical cell, comprising from about 25 wt % to about 40 wt % ZnBr2, from about 25 wt % to about 45 wt % water, and one or more quaternary ammonium agents, wherein the electrolyte has a polymeric concentration of the one or more quaternary ammonium agents from about 2.0 wt % to about 15.0 wt %, and wherein the one or more quaternary ammonium agents comprises at least hexadecyltrimethylammonium bromide, and tetraethylammonium bromide.

[0060] In some embodiments, the electrolyte includes about 0.2 wt % to about 1.2 wt % cetyltrimethylammonium bromide and about 2.0 wt % to about 6.0 wt % tetraethylammonium bromide.

[0061] In some embodiments, the electrolyte comprises about 0.5 wt % to about 2.0 wt % of N-ethyl-N-methylmorpholinium chloride or N-ethyl-N-methylmorpholinium bromide.

[0062] In some embodiments, the electrolyte comprises from about 1 wt % to about 5 wt % KBr. In some embodiments, the electrolyte comprises from about 5 wt % to about 15 wt % KCl.

[0063] In some embodiments, the electrolyte comprises about 1.0 wt % to about 5 wt % of glyme, wherein the ether is selected from diglyme, triglyme, or tetraglyme.

[0064] Another aspect of the present invention provides an electrolyte for use in a secondary zinc-bromine electrochemical cell comprising about 1.0 wt % to about 5 wt % tetra-alkylammonium chloride, about 25 wt % to about 40 wt % ZnBr2, and about 25 wt % to about 45 wt % water.

[0065] In some embodiments, the tetra-alkylammonium chloride is (C 1-6 Alkyl)4N + Cl - In other embodiments, the tetra-alkylammonium chloride is selected from triethylmethylammonium chloride, triethylpropylammonium chloride, butyltrimethylammonium chloride, tetraethylammonium chloride, trimethylethylammonium chloride, or any combination thereof. For example, the tetra-alkylammonium chloride is triethylmethylammonium chloride.

[0066] In some embodiments, the electrolyte comprises cetyltrimethylammonium bromide or cetyltrimethylammonium chloride.

[0067] In some embodiments, the electrolyte comprises tetraethylammonium bromide or tetraethylammonium chloride.

[0068] In some embodiments, the electrolyte includes about 0.2 wt % to about 1.2 wt % cetyltrimethylammonium bromide and about 1.5 wt % to about 5.0 wt % tetraethylammonium bromide.

[0069] In some embodiments, the electrolyte includes about 0.5 wt % to about 2.0 wt % of N-ethyl-N-methylmorpholinium chloride or N-ethyl-N-methylmorpholinium bromide.

[0070] In some embodiments, the electrolyte comprises about 2.5 wt % to about 7.5 wt % KBr.

[0071] In some embodiments, the electrolyte comprises about 5 wt % to about 15 wt % KCl.

[0072] In some embodiments, the electrolyte comprises about 0.1 wt % to about 0.5 wt % DME-PEG having an average molecular weight of about 750 amu to about 1250 amu.

[0073] In some embodiments, the electrolyte comprises about 1.0 wt % to about 2.0 wt % DME-PEG having an average molecular weight of about 1750 amu to about 2250 amu.

[0074] In some embodiments, the electrolyte comprises an acid or a conjugate base of an acid selected from acetic acid, nitric acid, and citric acid. For example, the electrolyte comprises about 0.1 wt % to about 1.0 wt % of glacial acetic acid or about 0.1 wt % to about 1.0 wt % of HBr.

[0075] Another aspect of the present invention provides an electrolyte for use in a secondary static zinc-halogen electrochemical cell, comprising: about 30.00 wt % to about 50.00 wt % (e.g., about 35 wt % to about 47.5 wt % or about 37 wt % to about 46 wt %) of ZnBr2, about 22.5 wt % to about 40 wt % (e.g., about 23.75 wt % to about 38 wt % or about 24 wt % to about 36 wt %) of H2O, about 3.00 wt % to about 9.5 wt % (e.g., ...3.5 wt % (e.g., about 24 wt % to about 36 wt %) of H2O, about 3.00 wt % to about 3.5 wt % (e.g., about 24 wt % to about 36 wt %) of H2O, about 3.00 wt % For example, about 4.00 wt % to about 8.5 wt %, about 3.00 wt % to about 8.5 wt %, or about 4.1 wt % to about 8 wt %) of KBr, about 7.75 wt % to about 14.00 wt % (e.g., about 7.9 wt % to about 13.25 wt % or about 8 wt % to about 13 wt %) of KCl, about 0.25 wt % to about 2.25 wt % (e.g., about 0.35 wt % to about 2.0 wt % or about 0.5 wt % to about 2 wt %) of MPEG 2K, and about 0.075 wt % to about 1.25 wt % (e.g., about 0.1 wt % to about 1 wt %) of MPEG 1K.

[0076] In some embodiments, the electrolyte further comprises at least two different quaternary ammonium agents, wherein both quaternary ammonium agents are of formula N + (R A )(R B )3X - Indicates that R A C 1-6 Alkyl, R B C 1-6 Alkyl, and X - Br - or Cl - ;And the aggregation concentration of the at least two different quaternary ammonium agents is about 3.50 weight % to about 20.00 weight %.In some examples, one of the at least two different quaternary ammonium agents is tetraethylammonium bromide, and the concentration of the tetraethylammonium bromide is about 0.35 weight % to about 3.75 weight %.In other examples, one of the at least two different quaternary ammonium agents is triethylmethylammonium chloride, and the concentration of the triethylmethylammonium chloride is about 3.50 weight % to about 15.0 weight %.

[0077] In some embodiments, the electrolyte further comprises a quaternary ammonium agent selected from trimethylpropylammonium bromide, and the trimethylpropylammonium bromide has a concentration of about 0.25 wt % to about 0.75 wt %.

[0078] In some embodiments, the electrolyte further comprises about 0.35 wt % to about 2.75 wt % of a glycol, wherein the glycol is selected from ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, hexylene glycol, or any combination thereof. For example, the electrolyte comprises about 0.35 wt % to about 2.75 wt % of neopentyl glycol.

[0079] In some embodiments, the electrolyte further comprises about 2.00 wt % to about 4.00 wt % of glyme, wherein the glyme is selected from monoglyme, diglyme, triglyme, tetraglyme, pentaglyme, hexaglyme, or any combination thereof. For example, the electrolyte further comprises about 2.00 wt % to about 4.00 wt % of tetraglyme.

[0080] Another embodiment of the present invention provides an electrolyte for use in a secondary static zinc-halogen electrochemical cell, comprising about 30.00 wt % to about 50.00 wt % (e.g., about 35 wt % to about 47.5 wt % or about 37 wt % to about 46 wt %) of ZnBr2, about 22.5 wt % to about 40 wt % (e.g., about 23.75 wt % to about 38 wt % or about 24 wt % to about 36 wt %) of H2O, about 3.00 wt % to about 9.5 wt % (e.g., ... For example, about 4.00 wt % to about 8.5 wt %, about 3.00 wt % to about 8.5 wt %, or about 4.1 wt % to about 8 wt %) of KBr, about 7.75 wt % to about 14.00 wt % (e.g., about 7.9 wt % to about 13.25 wt % or about 8 wt % to about 13 wt %) of KCl, about 0.25 wt % to about 2.25 wt % (e.g., about 0.35 wt % to about 2.0 wt % or about 0.5 wt % to about 2 wt %) of MPEG 2K, about 0.075 wt % to about 1.25 wt % (e.g., about 0.1 wt % to about 1 wt %) of MPEG 1K, and about 0.50 wt % to about 3.50 wt % of a first quaternary ammonium agent, wherein the first quaternary ammonium agent is selected from tetra-C 1-6 Alkyl ammonium chloride or tetra-C 1-6 Alkyl ammonium bromide.

[0081] In some embodiments, the first quaternary ammonium agent is selected from tetramethylammonium chloride, tetraethylammonium chloride, tetrapropylammonium chloride, tetrabutylammonium chloride, tetramethylammonium bromide, tetraethylammonium bromide, tetrapropylammonium bromide, or tetrabutylammonium bromide.

[0082] In some embodiments, the electrolyte further comprises a second quaternary ammonium agent, wherein the second quaternary ammonium agent has the formula N + (R A )(R B )3X - , where R A C 1-6 Alkyl, R B Different from R A C 1-6 Alkyl, and X - Br - or Cl - ;And wherein the concentration of the second quaternary ammonium agent is about 3.50 weight % to about 15.00 weight %.For example, the second quaternary ammonium agent is selected from the chloride or bromide of trimethylethylammonium, trimethylpropylammonium, trimethylbutylammonium, triethylmethylammonium, triethylpropylammonium, triethylbutylammonium, tripropylmethylammonium, tripropylethylammonium or tripropylbutylammonium.

[0083] In some embodiments, the electrolyte further comprises a third quaternary ammonium agent, wherein the third quaternary ammonium agent has the formula N + (R A )(R B )3X - , where R A C 1-6 Alkyl, R B Different from R A C 1-6 Alkyl, and X - Br - or Cl - The third quaternary ammonium agent is different from the second quaternary ammonium agent, and the concentration of the third quaternary ammonium agent is about 0.25% by weight to about 0.85% by weight. In some examples, the third quaternary ammonium agent is selected from: chloride or bromide of trimethylethylammonium, trimethylpropylammonium, trimethylbutylammonium, triethylmethylammonium, triethylpropylammonium, triethylbutylammonium, tripropylmethylammonium, tripropylethylammonium or tripropylbutylammonium.

[0084] In some embodiments, the electrolyte further comprises about 0.35 wt % to about 2.75 wt % (e.g., about 0.4 wt % to about 2.65 wt % or about 0.5 wt % to about 2.5 wt %) of a glycol, wherein the glycol is selected from ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, hexylene glycol, or any combination thereof. For example, the electrolyte further comprises about 0.35 wt % to about 2.75 wt % (e.g., about 0.4 wt % to about 2.65 wt % or about 0.5 wt % to about 2.5 wt %) of neopentyl glycol.

[0085] In some embodiments, the electrolyte further comprises about 2.00 wt % to about 4.00 wt % of glyme, wherein the glyme is selected from monoglyme, diglyme, triglyme, tetraglyme, pentaglyme, hexaglyme, or any combination thereof. For example, the electrolyte further comprises about 2.00 wt % to about 4.00 wt % of tetraglyme.

[0086] Another aspect of the present invention provides an electrolyte for use in a secondary static zinc-halogen electrochemical cell, comprising: about 30.00 wt % to about 50.00 wt % (e.g., about 35 wt % to about 47.5 wt % or about 37 wt % to about 46 wt %) of ZnBr2, about 22.5 wt % to about 40 wt % (e.g., about 23.75 wt % to about 38 wt % or about 24 wt % to about 36 wt %) of H2O, about 3.00 wt % to about 9.5 wt % (e.g., ...3.5 wt % (e.g., about 24 wt % to about 36 wt %) of H2O, about 3.00 wt % to about 3.5 wt % (e.g., about 24 wt % to about 36 wt %) of H2O, about 3.00 wt % For example, about 4.00 wt % to about 8.5 wt %, about 3.00 wt % to about 8.5 wt %, or about 4.1 wt % to about 8 wt %) of KBr, about 7.75 wt % to about 14.00 wt % (e.g., about 7.9 wt % to about 13.25 wt % or about 8 wt % to about 13 wt %) of KCl, about 0.25 wt % to about 2.25 wt % (e.g., about 0.35 wt % to about 2.0 wt % or about 0.5 wt % to about 2 wt %) of MPEG 2K, about 0.075 wt % to about 1.25 wt % (e.g., about 0.1 wt % to about 1 wt %) of MPEG 1K, and one or more quaternary ammonium agents, wherein each quaternary ammonium agent is independently selected from a quaternary ammonium agent having the formula N + (R A )(R B )3X - A quaternary ammonium agent, wherein R A C 1-6 Alkyl, R B C 1-6 Alkyl, and X - Br - or Cl - ; and wherein the one or more quaternary ammonium agents have an aggregate concentration of about 3.50 wt % to about 20.00 wt %.

[0087] In some embodiments, the electrolyte further comprises about 0.50 wt % to about 3.50 wt % of a first quaternary ammonium agent, wherein the first quaternary ammonium agent is selected from tetra-C 1-6 Alkyl ammonium chloride or tetra-C 1-6 Alkyl ammonium bromide. For example, the first quaternary ammonium agent is selected from tetramethylammonium chloride, tetraethylammonium chloride, tetrapropylammonium chloride, tetrabutylammonium chloride, tetramethylammonium bromide, tetraethylammonium bromide, tetrapropylammonium bromide, or tetrabutylammonium bromide.

[0088] In some embodiments, the electrolyte further comprises a second quaternary ammonium agent, wherein the second quaternary ammonium agent has the formula N + (R A )(R B )3X - , where R A C 1-6 Alkyl, R B Different from R A C 1-6 Alkyl, and X - Br - or Cl - ; And the concentration of the second quaternary ammonium agent is about 3.50 weight % to about 15.00 weight %. In some examples, the second quaternary ammonium agent is selected from the chloride or bromide of trimethylethylammonium, trimethylpropylammonium, trimethylbutylammonium, triethylmethylammonium, triethylpropylammonium, triethylbutylammonium, tripropylmethylammonium, tripropylethylammonium or tripropylbutylammonium. For example, the second quaternary ammonium agent is triethylmethylammonium chloride or triethylmethylammonium bromide.

[0089] In some embodiments, the electrolyte further comprises a third quaternary ammonium agent, wherein the third quaternary ammonium agent has the formula N + (R A )(R B )3X - , where R A C 1-6 Alkyl, R B Different from R A C 1-6 Alkyl, and X - Br - or Cl - The third quaternary ammonium agent is different from the second quaternary ammonium agent, and the concentration of the third quaternary ammonium agent is about 0.25% by weight to about 0.85% by weight. In some examples, the third quaternary ammonium agent is selected from the chloride or bromide of trimethylethylammonium, trimethylpropylammonium, trimethylbutylammonium, triethylmethylammonium, triethylpropylammonium, triethylbutylammonium, tripropylmethylammonium, tripropylethylammonium or tripropylbutylammonium.

[0090] In some embodiments, the electrolyte further comprises about 0.35 wt % to about 2.75 wt % (e.g., about 0.4 wt % to about 2.65 wt % or about 0.5 wt % to about 2.5 wt %) of a glycol, wherein the glycol is selected from ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, hexylene glycol, or any combination thereof. For example, the electrolyte further comprises about 0.35 wt % to about 2.75 wt % (e.g., about 0.4 wt % to about 2.65 wt % or about 0.5 wt % to about 2.5 wt %) of neopentyl glycol.

[0091] In some embodiments, the electrolyte further comprises about 2.00 wt % to about 4.00 wt % of glyme, wherein the glyme is selected from monoglyme, diglyme, triglyme, tetraglyme, pentaglyme, hexaglyme, or any combination thereof. For example, the electrolyte further comprises about 2.00 wt % to about 4.00 wt % of tetraglyme.

[0092] Another aspect of the present invention provides an electrolyte for use in a secondary static zinc-halogen electrochemical cell, comprising about 30.00 wt % to about 50.00 wt % (e.g., about 35 wt % to about 47.5 wt % or about 37 wt % to about 46 wt %) of ZnBr2, about 22.5 wt % to about 40 wt % (e.g., about 23.75 wt % to about 38 wt % or about 24 wt % to about 36 wt %) of H2O, about 3.00 wt % to about 9.5 wt % (e.g., about 15 wt % to about 20 wt % or about 18 wt %) of H2O, and about 10 wt % to about 25 wt % (e.g., about 20 wt % to about 25 wt % or about 18 wt %) of H2O. For example, about 4.00 wt % to about 8.5 wt %, about 3.00 wt % to about 8.5 wt %, or about 4.1 wt % to about 8 wt %) of KBr, about 7.75 wt % to about 14.00 wt % (e.g., about 7.9 wt % to about 13.25 wt % or about 8 wt % to about 13 wt %) of KCl, about 0.25 wt % to about 2.25 wt % (e.g., about 0.35 wt % to about 2.0 wt % or about 0.5 wt % to about 2 wt %) of MPEG 2K, about 0.075 wt % to about 1.25 wt % (e.g., about 0.1 wt % to about 1 wt %) of MPEG 1K, about 3.50 wt % to about 15.00 wt % of chloride or bromide of triethylmethylammonium, and about 0.50 wt % to about 3.50 wt % of tetra-C 1-6 Alkylammonium chlorides or bromides.

[0093] In some embodiments, the electrolyte further comprises about 0.25 wt % to about 0.75 wt % of a + (R A )(R B )3X - A quaternary ammonium agent, wherein RA C 1-6 Alkyl, R B Different from R A C 1-6 Alkyl, and X - Br - or Cl - ; And the alkylammonium agent is not the chloride or bromide of triethylmethylammonium. For example, the quaternary ammonium agent is selected from the chloride or bromide of trimethylethylammonium, trimethylpropylammonium, trimethylbutylammonium, triethylpropylammonium, triethylbutylammonium, tripropylmethylammonium, tripropylethylammonium, or tripropylbutylammonium.

[0094] In some embodiments, the electrolyte further comprises about 0.35 wt % to about 2.75 wt % (e.g., about 0.4 wt % to about 2.65 wt % or about 0.5 wt % to about 2.5 wt %) of a glycol, wherein the glycol is selected from ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, hexylene glycol, or any combination thereof. For example, the electrolyte further comprises about 0.35 wt % to about 2.75 wt % (e.g., about 0.4 wt % to about 2.65 wt % or about 0.5 wt % to about 2.5 wt %) of neopentyl glycol.

[0095] In some embodiments, the electrolyte further comprises about 2.00 wt % to about 4.00 wt % of glyme, wherein the glyme is selected from monoglyme, diglyme, triglyme, tetraglyme, pentaglyme, hexaglyme, or any combination thereof. For example, the electrolyte further comprises about 2.00 wt % to about 4.00 wt % of tetraglyme. BRIEF DESCRIPTION OF THE DRAWINGS

[0096] These and other features, aspects and advantages of the present invention will be better understood when the following detailed description is read with reference to the accompanying drawings.

[0097] Figure 1 An exploded view of an electrochemical cell according to an embodiment of the present invention is shown.

[0098] Figure 2A and 2B 3 and 4 respectively show a front view and a side view of a bipolar electrode according to an embodiment of the present invention.

[0099] Figure 3 An exploded view of a bipolar electrode according to an embodiment of the present invention is shown.

[0100] Figure 4A A front view of a bipolar electrode according to an embodiment of the present invention is shown.

[0101] Figure 4BAn exploded view of a bipolar electrode according to an embodiment of the present invention is shown.

[0102] Figure 5 A view showing a rear surface of an electrode plate having a sandblasted area according to an embodiment of the present invention.

[0103] Fig. 6A and Figure 6B A front view and a side view of a cathode holder according to an embodiment of the present invention are respectively shown.

[0104] Fig. 7A and 7B A front view of a cathode holder and an enlarged view of cathode holder material having a hole therethrough are respectively shown according to an embodiment of the present invention.

[0105] Figure 8 A cross-sectional view of a portion of an electrochemical cell having an interface between a front surface of a bipolar electrode plate (including a cathode assembly mounted thereon) and a rear surface of a second electrode plate or an inner surface of a terminal end plate according to an embodiment of the present invention is shown.

[0106] Fig. 9 Front, side, and top perspective views of a carbon material used as a cathode according to an embodiment of the present invention are shown.

[0107] Fig.10 Experimental data of the spacing between the three-dimensional shape profiles of the bipolar electrode plate and the cathode holder according to an embodiment of the present invention with respect to the Z axis and the X axis are shown.

[0108] Fig.11 Experimental data of the spacing between the three-dimensional shape profiles of the bipolar electrode plate and the cathode according to an embodiment of the present invention with respect to the Z-axis and the X-axis are shown.

[0109] Fig.12 A perspective view showing a terminal assembly according to an embodiment of the present invention is shown.

[0110] Fig.13 A top perspective view of a terminal assembly for a bipolar battery according to an embodiment of the present invention is shown, which includes a terminal end plate and a conductive cup-shaped member having a generally oval edge joined to the end plate.

[0111] Fig.14 The embodiment of the present invention is shown Fig.13 A top view of an end plate of a terminal assembly having an electrochemically active area including a first surface area surrounded by an edge of a conductive cup-shaped member and a remaining second surface defined by an outer perimeter of the edge and a peripheral edge of the electrochemically active area.

[0112] Fig.15 According to an embodiment of the present invention, Fig.13 A cross-sectional view taken along line 17-17 of FIG. 1 shows the conductive cup-shaped member and the remaining second surface defined by the outer perimeter of the rim and the peripheral edge of the electrochemically active area.

[0113] Fig.16 According to an embodiment of the present invention Fig.13 A top perspective view of a terminal assembly of , showing a bipolar end plate and a conductive cup-shaped member including a generally circular edge.

[0114] Fig.17 According to an embodiment of the present invention, Fig.13 A cross-sectional view taken along line 15 - 15 of FIG. 1 shows the terminal assembly further comprising a frame member opposed to and received on the second surface of the end plate on the side opposite to the conductive cup-shaped member.

[0115] Fig.18 is a side view of a battery pack including cathode and anode terminals with bipolar electrodes and frame members between press plates according to an embodiment of the present invention.

[0116] Fig.19 is a top perspective view of a battery pack according to an embodiment of the present invention, which includes a pair of terminal assemblies at corresponding proximal and distal ends of a battery module.

[0117] Fig. 20 According to an embodiment of the present invention Fig.18 Exploded view of the battery pack.

[0118] Fig.21 Shown for Fig. 20 A front view of a seal used in a battery module and a cross-sectional view of the seal.

[0119] Fig. 22 The method for Fig.18 A top perspective view of the cathode terminal and anode terminal pressure plates of a battery pack.

[0120] Fig.23 The method for performing the Fig.18 Front and side views of a frame used in a battery pack.

[0121] Fig.24 The representative behavior of the battery pack according to the embodiment of the present invention in terms of discharge energy after several charging cycles is shown.

[0122] Fig.25A and 25B Representative behavior of a battery module according to an embodiment of the present invention is shown. Fig.25AThe operating time of the battery is shown relative to the average discharge power. Fig.25B The energy efficiency of the battery is shown relative to the average discharge power.

[0123] Fig.26 Representative behavior of a battery module according to an embodiment of the present invention in terms of the relationship between discharge energy and average discharge power is shown in terms of discharge energy.

[0124] Fig.27A and 27B Representative behavior of a battery module according to an embodiment of the present invention is shown. Fig.27A The energy efficiency of the battery after several discharge cycles is shown. Fig.27B The discharge runtime of the battery after several discharge cycles is shown.

[0125] Fig.28 The graphs of energy as a function of charge cycles in test cells employing the electrolyte of the present invention and electrolytes reported in the open literature show representative behavior of electrolytes according to embodiments of the present invention.

[0126] Fig.29A Representative behavior of electrolytes according to embodiments of the present invention is shown in terms of capacity as a function of charge cycles in test cells employing electrolytes of the present invention and electrolytes reported in the open literature.

[0127] Fig.29B Representative behavior of electrolytes according to embodiments of the present invention are shown in terms of potential as a function of charge cycles in test cells employing electrolytes of the present invention and electrolytes reported in the literature.

[0128] Fig. 30A and 30B is a photograph of zinc metal plated on the rear surface of an electrode plate with a corresponding cathode holder having an unadjusted hole pattern.

[0129] Fig.31A , 31B and 31C are photographs of zinc metal plated on the rear surface of an electrode plate with a corresponding cathode holder having an adjusted hole pattern.

[0130] Fig.32 Representative behavior of various bromine complexing agents is shown in terms of power (maximum power at the limiting current for Br2 reduction) as a function of stability (change in pH after 7 days at 60°C).

[0131] Fig.33 A comparison of the bromine activity of various ethyl picoliniums is shown in terms of logarithmic current as a function of voltage.

[0132] Fig.34 A comparison of different polyethers of bromine complexing agents is shown in terms of power (maximum power at the limiting current for Br2 reduction) as a function of stability (change in pH after 7 days at 60°C).

[0133] Fig.35 is a graph of discharge capacity (mAh) versus charge cycle number for electrochemical cells of the present invention assembled to include Example 1 electrolyte formulation.

[0134] Fig.36 is a graph of coulombic efficiency (%) versus charge cycle number for electrochemical cells of the present invention assembled to include electrolyte formulation No. 1.

[0135] Fig.37 is a graph of run time (hours) versus charge cycle number for an electrochemical cell of the present invention assembled to include electrolyte formulation No. 1.

[0136] Fig.38 is a graph of energy efficiency (%) versus charge cycle number for an electrochemical cell of the present invention assembled to include electrolyte formulation No. 1.

[0137] Fig.39 A graph of cyclic voltammetry measurements for a battery of the present invention assembled to contain electrolyte formulation No. 5 is shown.

[0138] Fig.40 is an exploded view of a test cell according to an embodiment of the present invention and described in Example 6A

[0139] Fig.41 is a top view of a test cell according to an embodiment of the present invention and described in Example 6A.

[0140] Fig.42 is a perspective view of a test cell described in Example 6A according to an embodiment of the present invention.

[0141] Fig.43 is a top view of the housing and reaction chamber of the test cell described in Example 6A according to an embodiment of the present invention.

[0142] Fig.44 Graphs of energy and coulombic efficiency are shown for test cells according to Example 6A.

[0143] Fig.45 Graphs of energy and coulombic efficiency of a test cell according to Example 6B are shown.

[0144] Fig.46A graph showing a Tafel plot of ethyl methylpyridine according to Example 6B is shown.

[0145] Fig.47 A graph showing energy efficiency versus cycle number for a test cell according to Example 8 is shown.

[0146] Fig.48 A graph showing the coulombic efficiency versus cycle number for a test cell according to Example 8 is shown.

[0147] Fig.49 A graph showing the charge and discharge capacities of a test battery according to Example 8 is shown.

[0148] Fig.50 A graph showing the charge and discharge energy of a test battery according to Example 8 is shown.

[0149] Fig.51 A graph showing the change in ToC (maximum charge) voltage versus cycle number for a test battery according to Example 8 is shown.

[0150] Fig.52 A graph of the voltage change from ToC (maximum charge) to discharge versus cycle number for a test cell according to Example 8 is shown.

[0151] Fig.53 A graph showing energy efficiency versus cycle number for a test cell according to Example 9 is shown.

[0152] Fig.54 A graph of coulombic efficiency versus cycle number for a test cell according to Example 9 is shown.

[0153] Fig.55 A graph showing the charge and discharge capacities of a test battery according to Example 9 is shown.

[0154] Fig.56 A graph showing the charge and discharge energy of a test battery according to Example 9 is shown.

[0155] Fig.57 A graph showing the change in ToC (maximum charge) voltage versus cycle number for a test battery according to Example 9 is shown.

[0156] Fig.58 A graph of the voltage change from ToC (maximum charge) to discharge versus cycle number for a test cell according to Example 9 is shown.

[0157] Fig.59 A graph of energy efficiency versus cycle number for a test cell according to Example 10 is shown.

[0158] Fig.60 A graph of coulombic efficiency versus cycle number for a test cell according to Example 10 is shown.

[0159] Fig.61 A graph showing the charge and discharge capacities of a test battery according to Example 10 is shown.

[0160] Fig.62 A graph showing the charge and discharge energy of a test battery according to Example 10 is shown.

[0161] Fig.63 A graph showing the change in ToC (maximum charge) voltage versus cycle number for a test cell according to Example 10 is shown.

[0162] Fig.64 A graph of the voltage change from ToC (maximum charge) to discharge versus cycle number for a test cell according to Example 10 is shown.

[0163] The drawings are provided by way of illustration and are not intended to limit the scope of the invention. DETAILED DESCRIPTION

[0164] The present invention provides an electrolyte for use in a secondary, ie, rechargeable, zinc-halide energy storage battery (eg, a bipolar fluid or non-fluid battery). In some embodiments, the electrolyte of the present invention is for use in a non-fluid battery.

[0165] I. Definitions

[0166] As used herein, the terms "electrochemical cell" or "battery" are used interchangeably to refer to a device capable of generating electrical energy through a chemical reaction or facilitating a chemical reaction through the introduction of electrical energy.

[0167] As used herein, the term "battery" encompasses an electrical storage device comprising at least one electrochemical cell. A "secondary battery" is rechargeable, while a "primary battery" is non-rechargeable. For the secondary battery of the present invention, the battery anode is designated as the positive electrode during discharge and the negative electrode during charge.

[0168] As used herein, "electrolyte" refers to a substance that acts as an ion-conducting medium. For example, an electrolyte facilitates the transfer of electrons and cations in a battery. The electrolyte includes a mixture of materials such as an aqueous solution of a metal halide salt (e.g., ZnBr2, ZnCl2, etc.).

[0169] As used herein, the term "electrode" refers to an electrical conductor used to make contact with a non-metallic portion of an electrical circuit (eg, a semiconductor, an electrolyte, or a vacuum). An electrode may also be referred to as an anode or a cathode.

[0170] As used herein, the term "anode" refers to the negative electrode from which electrons flow during the discharge phase of a battery. The anode is also the electrode that undergoes chemical oxidation during the discharge phase. However, in a secondary or rechargeable battery, the anode is the electrode that undergoes chemical reduction during the charge phase of the battery. The anode is formed of a conductive or semiconductive material, for example, a metal (e.g., titanium or titanium coated with TiC), a metal oxide, a metal alloy, a metal composite, a semiconductor, and the like.

[0171] As used herein, the term "cathode" refers to the positive electrode into which electrons flow during the discharge phase of a battery. The cathode is also the electrode that undergoes chemical reduction during the discharge phase. However, in secondary or rechargeable batteries, the cathode is the electrode that undergoes chemical oxidation during the charge phase of the battery. The cathode is formed of a conductive or semiconductive material, for example, a metal, a metal oxide, a metal alloy, a metal composite, a semiconductor, and the like.

[0172] As used herein, the term "bipolar electrode" refers to an electrode that serves as the anode of one battery and the cathode of another battery. For example, in a battery pack, a bipolar electrode serves as the anode in one battery and as the cathode in an immediately adjacent battery. In some instances, a bipolar electrode includes two surfaces: a cathode surface and an anode surface, wherein the two surfaces are connected by a conductive material. For example, a bipolar electrode plate can have opposing surfaces, wherein one surface is an anode surface and the other surface is a cathode surface, and the conductive material has the thickness of the plate between the opposing surfaces.

[0173] As used herein, the term "halide" refers to a binary compound of a halogen with another element or radical that is less electronegative (or more electronegative) than the halogen to make a fluoride, chloride, bromide, iodide, or astatide compound.

[0174] As used herein, the term "halogen" refers to the elements fluorine, chlorine, bromine, iodine and astatine occupying Group VIIA (17) of the periodic table. Halogens are reactive non-metallic elements that form strongly acidic compounds with hydrogen, from which simple salts can be prepared.

[0175] As used herein, the term "anion" refers to any chemical entity having one or more permanent negative charges. Examples of anions include, but are not limited to, fluoride, chloride, bromide, iodide, arsenate, phosphate, arsenite, hydrogen phosphate, dihydrogen phosphate, sulfate, nitrate, hydrogen sulfate, nitrite, thiosulfate, sulfite, perchlorate, iodate, chlorate, bromate, chlorite, hypochlorite, hypobromite, carbonate, chromate, bicarbonate (bicarbonate), dichromate, acetate, formate, cyanide, amide, cyanate, peroxide, thiocyanate, oxalate, hydroxide, and permanganate.

[0176] As used herein, "glyme" refers to an ether (e.g., an ethylene glycol ether). Examples include, but are not limited to, monoglyme (i.e., 1,2-ethylene glycol dimethyl ether), diglyme (i.e., bis(2-methoxyethyl) ether), tetraglyme (i.e., tetraethylene glycol dimethyl ether), pentaglyme, hexaglyme, heptaglyme, or any combination thereof.

[0177] As used herein, "titanium material" may include, but is not limited to, titanium (in any oxidation state), TiC, alloys of TiC (e.g., TiC x M) (wherein x is 0, 1, 2, 3, or 4 and M is a metal), titanium carbide, titanium oxycarbide, titanium oxynitride, titanium oxycarbonitride, titanium suboxide, non-stoichiometric titanium-nitrogen compounds, and any combination thereof.

[0178] As used herein, "titanium carbide" is used interchangeably with "titanium carbide material" and includes, but is not limited to, TiC, alloys of TiC (e.g., TiC x M, wherein x is 0, 1, 2, 3 or 4 and M is a metal), titanium carbides, non-stoichiometric titanium-nitrogen compounds, and combinations thereof.

[0179] As used herein, the term "zinc metal" refers to elemental zinc, also commonly referred to as Zn(0) or Zn 0 .

[0180] As used herein, the terms "dimethyl ether poly(ethylene glycol)", "DME-PEG" and "MPEG" are used interchangeably to refer to poly(ethylene glycol) having the structure wherein n is an integer. DME-PEG 1000 (or MPEG 1K) refers to a polymer having a number average molecular weight (M n ), while DME-PEG 2000 (or MPEG 2K) refers to a DME-PEG polymer having a number average molecular weight (M) of about 2000. n ) of DME-PEG polymer.

[0181] As used herein, the term "dimethyl ether" refers to an organic compound having the formula CH3OCH3.

[0182] As used herein, the term "aggregate concentration" refers to the sum total concentration (e.g., weight %) of each component in a class of ingredients or agents (e.g., quaternary ammonium agents). In one example, the aggregate concentration of one or more quaternary ammonium agents in an electrolyte is the sum total concentration (e.g., weight percent) of each of the constituent quaternary ammonium agents present in the electrolyte. Thus, if the electrolyte has three quaternary ammonium agents, the aggregate concentration of the three quaternary ammonium agents is the sum of the concentrations of each of the three quaternary ammonium agents present in the electrolyte. And, if the electrolyte has only one quaternary ammonium agent, the aggregate concentration of the quaternary ammonium agent is simply the concentration of the single quaternary ammonium agent present in the electrolyte.

[0183] As used herein, the term "alcohol" refers to any organic compound whose molecule contains one or more hydroxyl groups attached to a carbon atom. Examples of alcohols include methanol, ethanol, 1-propanol (i.e., n-propanol), 2-propanol (i.e., isopropanol), 1-butanol (i.e., n-butanol), sec-butanol, isobutanol, tert-butanol, 1-pentanol, or any combination thereof.

[0184] As used herein, the term "hydroxyl group" refers to an -OH group.

[0185] As used herein, the term "diol" refers to any of a class of organic compounds belonging to the alcohol family. In a diol molecule, two hydroxyl (-OH) groups are attached to different carbon atoms. Examples of diols include C 1-10 A diol including ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, hexanediol, or any combination thereof. Other examples of diols include substituted ethylene glycols and substituted propylene glycols.

[0186] As used herein, the term "weight percent" and its abbreviation "wt%" are used interchangeably to refer to the product of the mass of one or more components divided by the total mass of a mixture or product containing the components, multiplied by 100 times.

[0187] wt% = 100% x (mass of component / total mass)

[0188] When referring to the concentration of a component or ingredient of an electrolyte, as described herein, the weight percent is based on the total weight of the electrolyte.

[0189] As used herein, the term "quaternary ammonium agent" refers to any compound, salt or material containing a quaternary nitrogen atom. For example, quaternary ammonium agents include: ammonium halides (e.g., NH4Br, NH4Cl or any combination thereof), tetraalkylammonium halides (e.g., tetramethylammonium bromide, tetramethylammonium chloride, tetraethylammonium bromide, tetraethylammonium chloride, alkyl-substituted pyridinium halides, alkyl-substituted morpholine halides, combinations thereof, etc.), heterocyclic ammonium halides (e.g., alkyl-substituted pyrrolidinium halides (e.g., N-methyl-N-ethylpyrrolidinium halides or N-ethyl-N-methylpyrrolidinium halides), alkyl-substituted pyridinium halides, alkyl-substituted morpholine halides, viologens with at least one quaternary nitrogen atom, combinations thereof, etc.), or any combination thereof. Tetraalkylammonium halides can be symmetrically substituted or asymmetrically substituted with respect to the substituent of the quaternary nitrogen atom.

[0190] As used herein, the term "viologen" refers to any bipyridinium salt derivative of 4-4'-bipyridine.

[0191] As used herein, the term "ammonium bromide complexing agent" refers to any compound, salt, or material containing a quaternary nitrogen atom, wherein the quaternary nitrogen atom is not part of an imidazolium, pyridinium, pyrrolidinium, morpholine, or phosphonium moiety. Examples of ammonium bromide complexing agents include tetraethylammonium bromide, trimethylpropylammonium bromide, dodecyltrimethylammonium bromide, hexadecyltriethylammonium bromide, and hexyltrimethylammonium bromide.

[0192] As used herein, the term "imidazolium bromide complexing agent" refers to any compound, salt or material containing a quaternary nitrogen atom, wherein the quaternary nitrogen atom is part of an imidazolium moiety. Examples of imidazolium bromide complexing agents include: 1-ethyl-3-methylimidazolium bromide, 1-butyl-3-methylimidazolium bromide, 1-ethyl-2,3-dimethylimidazolium bromide, 1-decyl-3-methylimidazolium bromide, 1-butyl-2,3-dimethylimidazolium bromide, 1-methyl-3-octylimidazolium bromide, and 1-methyl-3-hexylimidazolium bromide.

[0193] As used herein, the term "pyridinium bromide complexing agent" refers to any compound, salt or material containing a quaternary nitrogen atom, wherein the quaternary nitrogen atom is part of a pyridinium moiety. Examples of pyridinium bromide complexing agents include: 1-ethyl-2-methylpyridinium bromide, 1-ethyl-3-methylpyridinium bromide, 1-ethyl-4-methylpyridinium bromide, 1-butyl-3-methylpyridinium bromide, 1-butyl-3-methylpyridinium bromide, 1-butyl-4-methylpyridinium bromide, and 1-hexylpyridinium bromide.

[0194] As used herein, the term "pyrrolidinium bromide complexing agent" refers to any compound, salt or material containing a quaternary nitrogen atom, wherein the quaternary nitrogen atom is part of a pyrrolidinium moiety. An example of a pyrrolidinium bromide complexing agent is 1-butyl-1-methylpyrrolidinium bromide.

[0195] As used herein, the term "morpholinium bromide complexing agent" refers to any compound, salt or material containing a quaternary nitrogen atom, wherein the quaternary nitrogen atom is part of a morpholinium moiety. An example of a morpholinium bromide complexing agent is N-ethyl-N-methylmorpholinium bromide.

[0196] As used herein, the term "phosphonium bromide complexing agent" refers to any compound, salt, or material that contains a quaternary phosphorus atom. An example of a phosphonium bromide complexing agent is tetraethylphosphonium bromide.

[0197] As used herein, the term "crown ether" refers to a cyclic compound consisting of a ring containing at least three ether groups. Examples of crown ethers include 12-crown-4, 15-crown-5, 18-crown-6, dibenzo-18-crown-6, and diaza-18-crown-6.

[0198] As used herein, an "alkyl" group refers to a saturated aliphatic hydrocarbon group containing 1 to 20 (e.g., 1 to 16, 1 to 12, 1 to 8, 1 to 6, or 1 to 4) carbon atoms. The alkyl group can be straight-chain or branched. Examples of alkyl groups include, but are not limited to, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, 2-ethylhexyl, octyl, nonyl, decyl, dodecyl, and hexadecyl.

[0199] As used herein, an "aryl" group, used alone or as part of a larger moiety such as "aralkyl," "aryloxy," or "aryloxyalkyl," refers to a monocyclic (e.g., phenyl), bicyclic (e.g., indenyl, naphthyl, tetrahydronaphthyl, tetrahydroindenyl), tricyclic (e.g., fluorenyl, tetrahydrofluorenyl, anthracenyl, or tetrahydroanthracenyl) or benzofused group having three rings. For example, a benzofused group includes a benzofused group with two or more C 4-8The phenyl group is fused to a carbocyclic structure. The aryl group is optionally substituted with one or more substituents including: aliphatic (e.g., alkyl, alkenyl, or alkynyl), cycloalkyl, (cycloalkyl)alkyl, heterocycloalkyl, (heterocycloalkyl)alkyl, aryl, heteroaryl, alkylcyclyloxy, cycloalkyloxy, heterocycloalkyloxy, aryloxy, heteroaryloxy, aralkyloxy, heteroaralkyloxy, aroyl, heteroaroyl, amino, aminoalkyl, nitro, carboxyl, carbonyl (e.g., alkoxycarbonyl, alkylcarbonyl, carbamoyl, (alkylamino)alkylaminocarbonyl, arylaminocarbonyl, heteroarylaminocarbonyl, or sulfonylcarbonyl), aralkylcarbonyloxy, sulfonyl (e.g., alkylsulfonyl or aminosulfonyl), sulfinyl (e.g., alkylsulfinyl), sulfonamide (e.g., alkylsulfonamide), cyano, halo, hydroxy, acyl, sulfhydryl, sulfoxy, urea, thiourea, sulfamoyl, sulfamide, oxy, or carbamoyl. Alternatively, an aryl group may be unsubstituted.

[0200] Examples of substituted aryl groups include haloaryl, alkoxycarbonylaryl, alkylaminoalkylaminocarbonylaryl, p,m-dihaloaryl, p-amino-p-alkoxycarbonylaryl, m-amino-m-cyanoaryl, aminoaryl, alkylcarbonylaminoaryl, cyanoalkylaryl, alkoxyaryl, aminosulfonylaryl, alkylsulfonylaryl, aminoaryl, p-halo-m-aminoaryl, cyanoaryl, hydroxyalkylaryl, alkoxyalkylaryl, hydroxyaryl, carboxyl Alkylaryl, dialkylaminoalkylaryl, m-heterocycloaliphatic-o-alkylaryl, heterocycloaminocarbonylaryl, nitroalkylaryl, alkylsulfonylaminoalkylaryl, heterocycloaliphaticcarbonylaryl, alkylsulfonylalkylaryl, cyanoalkylaryl, heterocycloaliphaticcarbonylaryl, alkylcarbonylaminoaryl, hydroxyalkylaryl, alkylcarbonylaryl, aminocarbonylaryl, alkylsulfonylaminoaryl, dialkylaminoaryl, alkylaryl, and trihaloalkylaryl.

[0201] As used herein, an "aralkyl" group refers to an alkyl group substituted with an aryl group (e.g., C 1-4 "Alkyl" and "aryl" are both defined herein. An example of an aralkyl group is benzyl. A "heteroaralkyl" group refers to an alkyl group substituted with a heteroaryl group.

[0202] As used herein, a "cycloalkyl" group refers to a saturated carbocyclic, mono-, di-, or tri-, or polycyclic (fused or bridged) ring having 3 to 10 (e.g., 5 to 10) carbon atoms. Without limitation, examples of monocyclic cycloalkyl groups include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, etc. Without limitation, examples of bicyclic cycloalkyl groups include octahydro-indenyl, decahydro-naphthyl, bicyclo[3.2.1]octyl, bicyclo[2.2.2]octyl, bicyclo[3.3.1]nonyl, bicyclo[3.3.2.]decyl, bicyclo[2.2.2]octyl, bicyclo[2.2.1]heptyl, bicyclo[3.1.1]heptyl, etc. Without limitation, polycyclic groups include adamantyl, cubic alkyl (cubyl), norbornyl, etc. Cycloalkyl rings may be optionally substituted at any chemically variable ring position.

[0203] As used herein, a "heterocycloalkyl" group refers to a 3- to 10-membered monocyclic or bicyclic (fused or bridged) (e.g., a 5- to 10-membered monocyclic or bicyclic) saturated ring structure in which one or more of the ring atoms is a heteroatom (e.g., N, O, S, or a combination thereof). Examples of heterocycloalkyl groups include optionally substituted piperidinyl, piperazinyl, tetrahydropyranyl, tetrahydrofuranyl, 1,4-dioxolanyl, 1,4-dithianyl, 1,3-dioxolanyl, oxazolidyl, isoxazolidyl, morpholinyl, thiomorpholinyl, octahydro-benzofuranyl, octahydro-benzopyranyl, octahydro-thiobenzopyranyl, octahydro-indolyl, octahydro-pyridinyl, decahydro-quinolinyl, octahydro-benzo[b]thiophenyl, 2-oxa-bicyclo[2.2.2]octyl, 1-aza-bicyclo[2.2.2]octyl, 3-aza-bicyclo[3.2.1]octyl, 2,6-dioxa-tricyclo[3.3.1.0 3,7 ]nonyl, tropane. Monocyclic heterocycloalkyl groups can be fused to phenyl moieties such as tetrahydroisoquinoline. The heterocycloalkyl ring structure can be optionally substituted at any chemically variable position on the ring or rings.

[0204] As used herein, a "heteroaryl" group refers to a monocyclic, bicyclic, or tricyclic ring structure having 4 to 15 ring atoms, wherein one or more of the ring atoms is a heteroatom (e.g., N, O, S, or a combination thereof) and wherein one or more rings of the bicyclic or tricyclic ring structure are aromatic. Heteroaryl groups include benzo-fused ring systems having 2 to 3 rings. For example, benzo-fused groups include benzo-fused ring systems with one or two C 4-8Benzo fused to a heterocyclic moiety (e.g., indolizyl, indolyl, isoindolyl, 3H-indolyl, indolinyl, benzo[b]furanyl, benzo[b]phenylthio, quinolinyl, or isoquinolinyl). Some examples of heteroaryl are azetidinyl, pyridyl, 1H-indazolyl, furanyl, pyrrolyl, thienyl, thiazolyl, oxazolyl, imidazolyl, tetrazolyl, benzofuranyl, isoquinolyl, benzothiazolyl, xanthene, thioanthene, phenothiazine, indoline, benzo[1,3]dioxole, benzo[b]furanyl, benzo[b]phenylthio, indazolyl, benzimidazolyl, benzothiazolyl, puryl, cinnolinyl, quinolyl, quinazolinyl, cinnolinyl, phthalyl, quinazolinyl, quinoxalinyl, isoquinolyl, 4H-quinolizyl, benzo-1,2,5-thiadiazolyl, or 1,8-naphthyridyl. Heteroaryl also includes bipyridine compounds.

[0205] II. Electrochemical Cells and Batteries

[0206] refer to Figures 1 to 23 In one aspect, the present invention provides a static (non-flowing) bipolar zinc-halogen rechargeable electrochemical cell 100 and a battery 1000 of such cells.

[0207] A. Bipolar Electrochemical Cell

[0208] The bipolar electrochemical cell 100 of the present invention includes bipolar electrodes 102, terminal assembly 104, and zinc-halide electrolyte. The top and bottom 228, 228' of the two adjacent electrochemical cell housings are as shown in FIG. Figure 8 shown.

[0209] 1. Bipolar Electrode

[0210] The bipolar electrodes 102, 102' of the present invention include a bipolar electrode plate 208 having a front surface 212 and a rear surface 214, 214', wherein the cathode assembly 202 is attached to the front surface of the bipolar electrode plate so that the cathode assembly is in electrical communication with at least the front surface of the bipolar electrode plate 208. The bipolar electrodes 102 of the present invention are configured to plate zinc metal on the anode electrode surface (e.g., the rear surface of an adjacent bipolar electrode or the inner surface of the end plate of a terminal anode assembly) and produce reversely separated halides or mixed halide species in the cathode assembly during charging of the electrochemical cell. Conversely, these electrodes are configured to oxidize the plated zinc metal to produce Zn during discharge of the electrochemical cell. 2+ cations and reduce halides or mixed halide species to their corresponding anions.

[0211] a. Bipolar electrode plate

[0212] The bipolar electrode plates 208, 208' of the present invention include a front surface 212 and a rear surface 214. The cathode assembly is located on the front surface 212 (e.g., cathode surface) of the bipolar electrode plate 208. In some embodiments, the bipolar electrode plate includes a conductive material that is inert relative to the zinc-halide electrolyte used in the electrochemical cell or battery pack. In some embodiments, the bipolar electrode plate 208 includes a titanium material (e.g., titanium or titanium oxide). In some examples, the bipolar electrode plate 208 further includes a coating or film covering at least a portion of the front surface 212, at least a portion of the rear surface 214, or at least a portion of both surfaces. In other embodiments, the bipolar electrode plate includes a titanium material coated with a titanium carbide material. And, in some embodiments, the bipolar plate includes a titanium material thermally diffused with carbon. In these embodiments, at least a portion of the front surface 212, at least a portion of the rear surface 214, or at least a portion of both surfaces is coated with a titanium carbide material or thermally diffused with carbon. In some embodiments, the bipolar electrode plate includes a conductive carbon material (e.g., a graphite plate). In some examples, the bipolar electrode plate comprises a graphite plate coated with a titanium carbide material. In these embodiments, at least a portion of the front surface 212, the rear surface 214, or at least a portion of either of these surfaces is coated with a titanium carbide material.

[0213] The bipolar electrode plate of the present invention optionally includes a recessed portion 215, 215' on the front surface 212 of the bipolar electrode plate. In some embodiments, the bipolar electrode plate includes a recessed portion 215, 215' on the front surface 212 of the bipolar electrode plate. In some of these embodiments, the peripheral edge of the recessed portion 215, 215' is substantially defined by the outermost edge of the flange 220 of the cathode holder 216 of the cathode assembly 202, so that the cathode assembly is at least partially mounted in the recessed portion 215, 215' when the bipolar electrode is assembled. In other embodiments, the peripheral edge of the recessed portion is at least partially within the outermost edge of the flange 220 of the cathode holder 216 of the cathode assembly 202. In some of these embodiments, the recessed portion may be defined by the outermost edge of the carbon material 224 embedded within the cathode holder 216 of the cathode assembly 202, such that the carbon material 224 is at least partially mounted within the recessed portion 215, 215' of the bipolar electrode plate when the bipolar electrode 102 is assembled. Also, in some alternative embodiments, the front surface 212 of the bipolar electrode plate is free of the recessed portion, such that the surface is at least generally flat.

[0214] The bipolar electrode plates of the present invention may optionally include one or more through holes at or near the periphery 204 of the plate. Figure 2A4, in some embodiments, the bipolar electrode plate includes one or more through holes 206, 210 at or near the perimeter 204 of the plate, which can be used to fill the electrochemical cell with a liquid electrolyte or can be used to align the electrolyte plate in a battery pack.

[0215] The bipolar electrolyte plate can be formed by stamping or other suitable processes. A portion of the front surface 212, a portion of the rear surface 214, or a portion of both surfaces may optionally be subjected to surface treatment (e.g., coating, etc.) to enhance the electrochemical properties of the battery or battery pack. The rear surface of the bipolar electrode plate may include an electrochemically active region, which is associated with or defined by the formation of a zinc metal layer when the battery or battery pack is charged. In some embodiments, the rear surface of the electrode plate may be sandblasted (e.g., using SiC or garnet sandblasting), textured, or otherwise processed within the electrochemically active region. In other embodiments, the front surface may be sandblasted within the electrochemically active region associated with the region surrounded by the cathode assembly.

[0216] For example, in some embodiments, at least a portion of the rear surface, at least a portion of the front surface, or at least a portion of both surfaces is treated (e.g., sandblasted) to obtain a rough surface. In some examples, at least a portion of the rear surface of the bipolar electrode plate is treated (e.g., sandblasted) to obtain a rough surface 217. In some examples, the area of ​​the rear surface treated to obtain a rough surface is substantially defined by the perimeter of the cathode assembly attached to the front surface of the electrode plate.

[0217] b. Cathode assembly

[0218] The electrochemical cells and batteries of the present invention include at least one cathode assembly 202 , wherein the cathode assembly is formed by a cathode holder 216 , a carbon material 224 , and a separator 222 .

[0219] i. Cathode holder

[0220] The cathode holder 216 includes pocket portions 218, 218' and a flange 220 and is disposed on the front surface 212, 212' of the bipolar electrode plate or the inner surface 316 of the terminal end plate at the flange 220. Fig. 6A and 6B , showing a front view of the cathode holder 216 ( Fig. 6A ) and side view ( Figure 6B). The cathode holder 216 includes a total area defined by a length X1 and a width Y1, including the flange 220. In order to form the flange, a flat sheet of metal is mounted on a forming machine to press a flange on each of the four edges of the flat sheet. In some embodiments, the flat sheet of metal comprises titanium or titanium carbide material. In some embodiments, the cathode holder further comprises slits at the corners of the holder. These slits can be formed by laser cutting. The cathode holder 216 includes a reduced area defined by a length X2 and a width Y2 corresponding to the pocket portions 218, 218'. Accordingly, X1 is greater than X2 and Y1 is greater than Y2. In the example shown, the flange 220 is bent flatter relative to the pocket portions 218, 218' to represent the X1 / X2 and Y1 / Y2 dimensions and the depth of the pocket portion. In some embodiments, the area defined by X2 and Y2 represents an etched area in which a plurality of holes 227 are formed. The length X1 / X2 and the width Y1 / Y2 may vary depending on the operating requirements of the electrochemical cell 100 or the battery pack 1000 .

[0221] In some embodiments, the flange 220 includes a surface adjacent to and in contact with the front surface 212 of the bipolar electrode plate, and the depth of the pocket portion 218 extends from the flange in a direction away from the front surface of the electrode plate. The pocket portion 218 of the cathode holder cooperates with the front surface of the electrode plate to form a chamber in which the separator 222 and the carbon material 224 are located. In some of these embodiments, the cathode holder is disposed on the front surface of the electrode plate at its flange by welding, using an adhesive, using mechanical fasteners, or any combination thereof.

[0222] The cathode holder is formed of a metal, metal alloy or plastic that is substantially inert relative to the electrolyte of the electrochemical cell or battery. In some embodiments, the cathode holder is stamped from a titanium material (e.g., titanium or titanium oxide). In other embodiments, the cathode holder comprises a titanium material coated with a titanium carbide material.

[0223] In some embodiments, the pocket portion of the cathode holder is chemically etched to form a plurality of spaced-apart holes 227. In some embodiments, the size and spacing of the holes are designed to form a hole pattern (e.g., a regulated hole pattern) that increases the uniformity of current and / or charge distributed across the cathode holder by compensating for deformation or bending of the pocket portion of the cathode holder during operation (e.g., charging or discharging) of the electrochemical cell.

[0224] Fig. 7A Shown by Fig. 6A A front view of cathode holder 216 is shown including a plurality of holes 227 formed through the chemically etched surface of pocket portion 218 by chemical etching. Figure 7B Is Fig. 7ADetailed view of a portion shown, which shows the distribution of multiple holes 227. The chemical etching process is a subtractive manufacturing process that eliminates solid material to be removed for forming multiple holes 227. During the first step of the chemical etching process, the cathode holder 216 is initially a flat metal sheet, which is cut using a shearing machine to obtain dimensions corresponding to X1 and Y1. Next, the metal sheet can be cleaned and coated with a solder resist dry film in a hot roller laminator, and then cooled in a dark environment. A protective film can then be applied in a vacuum exposure unit to expose the metal sheet. In some examples, the amount of exposure can be measured using a step indicator, and the exposure is determined when the desired exposure amount is obtained. Subsequently, the metal sheet is passed through a developer to remove the protective film, while a decomposing detergent in the developer is applied to the metal sheet to remove excess unexposed resist. The metal sheet can then be placed on a heated furnace rack and baked at a predetermined temperature for a predetermined period of time. For example, the baking temperature can be about 250°F for about 60 minutes. After the baking cycle, each metal sheet is air cooled and the chemical etching apparatus is programmed to the specifications of the desired etching area (e.g., the area defined by X2 and Y2), and the baked and cooled metal sheets are run through the metal etching apparatus to remove excess material and thereby form hole 227.

[0225] Reference now Figure 7B , the plurality of holes 227 are spaced and distributed in a pattern along rows. In some embodiments, the pattern is an alternating repeating pattern. In some embodiments, the pattern is selected to achieve uniform distribution of current on the cathode holder 216 during charging of the electrochemical cell or battery pack in the presence of bending and deformation of the cathode holder from being flat. Also refer to Figures 30A to 31C , providing a cathode holder having a hole pattern according to the present invention enhances the uniform distribution of charge and / or current, which produces a more uniform plating of zinc metal at the anode surface of the bipolar electrode plate (e.g., the rear surface 214 of the bipolar electrode plate, or the inner surface 318 of the end plate, or both surfaces) during the charging cycle. Similarly, the conversion between bromine and bromide ions at or near the cathode holder 216 can also be enhanced. In some embodiments, the spacing between each of the plurality of holes 227 in each row in the x-direction, the spacing between alternating rows in the y-direction, and the diameter of the hole are The cathode holder 216 may be selected to achieve a generally uniform distribution of charge and / or current on the cathode holder 216 based on the amount of bending or deformation of the cathode holder and bipolar electrode caused when the electrochemical cell or battery undergoes charging and discharging. In some embodiments, the distribution of x and y hole locations (e.g., spacing) in each of the x and y directions is based on the nominal hole area and recommended grid length of the cathode holder 216. The thickness of the surface of the pocket portion 218 can determine the size of the nominal hole area and recommended grid length. In some examples, the centers of adjacent multiple holes 227 along a row are spaced apart by about 0.067 cm in the x direction and each other row is spaced apart by about 0.152 cm in the y direction. As described in more detail below, the cathode holder 216 and the bipolar electrode plate 208, 208' or the terminal end plate 302 are bent from flat a greater distance at each component in areas farther from the periphery, resulting in the spacing between the cathode electrode and the anode electrode being shorter in the central area relative to the outer areas near the periphery. Generally speaking, as the spacing between the anode electrode and the cathode electrode decreases, the calculated hole diameter at the corresponding x and y hole locations will increase.

[0226] In some embodiments, the spacing between electrodes (e.g., between the cathode holder 216 and the rear surface 214 or the inner surface 318 of the bipolar electrode plate 208, 208', 302) is calculated at each of a plurality of evenly distributed x and y hole locations along the etched region of the cathode holder (e.g., the region defined by X2 and Y2). The xy origin may include Figure 7B The lower left boundary of the pocket portion 218 where the x-axis and the y-axis intersect is shown in . Thereafter, the hole area for each of the plurality of holes 227 can be calculated based on the calculated spacing between the cathode electrode and the anode electrode at each x and y position, the predetermined minimum spacing between the electrodes, and the nominal hole area. In some embodiments, the number of the plurality of holes 227 can be further based on the thickness of the surface of the pocket portion 218 of the cathode holder 216. In some examples, the predetermined minimum spacing is about 7.45 mm and the nominal hole area is about 1.08 mm 2 In some embodiments, the spacing between the anode electrode and the cathode electrode is calculated at each of a plurality of x and y positions along the etched region using the following fitting equation:

[0227] f=y0+a*x+b*y+c*x 2 +d*y 2 [1].

[0228] The coefficients of the fitting equation of equation [1] can be determined by measuring the flat change △ for each cathode holder 216 and the electrode plate 208' or the terminal end plate 302 of each bipolar electrode. The measurement results are obtained from multiple x and y hole positions on each cathode holder 216 and the corresponding positions at the electrode plate 208'. At each position, an average value is calculated for each of the multiple bipolar electrodes 102, for both the cathode holder 216 and the electrode plate 208' or the terminal end plate 302. The data corresponding to the calculated average value is used to determine the coefficients y0, a, b, c and d for each of the cathode holder and the electrode plate. In some embodiments, the direction of the change △ for each of the two electrodes is adjusted so that the flat distance between the two is the desired spacing, for example, about 10.0 mm, and the change △ for the electrode plate extends upward from about 0 mm and the change △ for the cathode holder extends downward from about 10.0 mm. Accordingly, the coefficients determined for each of the electrode plate and the cathode holder are as follows:

[0229] Electrode plate / terminal end plate

[0230] y0=-1.5787

[0231] a=0.8948

[0232] b=2.4920

[0233] c=-0.1268

[0234] d = -0.9132

[0235] e=0.0000

[0236] Cathode Cage

[0237] y0=10.8602

[0238] a=-0.5295

[0239] b=-1.5860

[0240] c=0.0814

[0241] d = 0.6857

[0242] e=0.0000

[0243] The new coefficients for the fitting equation input into equation [1] can be determined by subtracting the anode coefficients from the cathode coefficients. Accordingly, the new coefficients for the fitting equation [1] are as follows:

[0244] y0=12.4389

[0245] a=-1.4243

[0246] b=-4.078

[0247] c=0.2082

[0248] d=1.5989

[0249] e=0.0000

[0250] Prior to input into equation [1], the x and y hole positions must be normalized by the etched area for calculating the spacing of the plurality of holes 227. For example, each x position is divided by the length X2 of the pocket portion 218 and each y position is divided by the width Y2 of the pocket portion. Each normalized x and y hole position is then input into equation [1] along with the new coefficients determined above to determine the spacing between the anode and cathode electrodes at each x and y hole position. The fitting equation for equation [1] is a nonlinear three-dimensional parabola equation. In some embodiments, equation [1] is obtained using SigmaPlot software licensed from Systal Software Corporation. TM Software to execute.

[0251] In some embodiments, the area of ​​each hole in the plurality of holes 227 at each x and y position may be calculated as follows:

[0252]

[0253] in is the calculated diameter at each hole location,

[0254] f is the spacing between electrodes at each hole location calculated using Equation 1,

[0255] A nominal is the nominal hole area, and

[0256] S nominal_minimum is the nominal minimum hole spacing.

[0257] In some examples, the nominal hole area is about 1.08 mm 2 And the nominal minimum spacing is 7.45mm 2 . The example used to calculate the hole diameter utilizes mixed units, where inches are used for each of the x and y hole locations and the etched area defined by X2 and Y2, and millimeters are used for calculating the spacing between the electrodes. Equation [2] demonstrates that the hole diameter increases as the spacing between the anode and cathode electrodes increases. The average hole diameter calculated at each hole location using Equation 2 for each of the bipolar electrodes 102, 102' is averaged. An embodiment includes utilizing the average hole diameter for the multiple holes 227 formed in the cathode holder 216 of each of the multiple bipolar electrodes 102, 102'.

[0258] Fig.10 and 11 The average spacing between the three-dimensional shape profiles of the bipolar electrode plate 208' and the cathode holder 216 is shown relative to the x-axis ( Fig.10 ) and the y-axis ( Fig.11 ). The experimental data shows the average value obtained from twenty bipolar electrodes 102, 102' of the battery module 1000. The electrode plate 208' and the cathode holder 216 are bent from flat when being charged. In the example shown, the cathode holder and the electrode plate are arranged so that the spacing between the cathode holder and the electrode plate is about 10 mm relative to the z-axis. The electrode plate has a maximum variation △ of about 1.566 mm in distance from flat along the z-axis at the direct center (for example, about 3.5 mm relative to the x-axis), and the cathode holder has a maximum variation △ of about 0.565 mm in distance from flat along the x-axis at the right center (for example, about 2.0 mm relative to the x-axis). The average electrode spacing from the left center to the right center of the plurality of bipolar electrodes is about 7.78 mm.

[0259] ii. Carbon materials

[0260] The carbon material 224 is electrically connected to the front surfaces 212, 212' of the bipolar electrode plates 208, 208' and is constrained by the cathode holders 216, 216', the separator 222, and the front surfaces 212, 212' of the bipolar electrode plates. Carbon materials suitable for the electrochemical cells of the present invention can include any carbon material that is capable of reversibly absorbing aqueous bromine (e.g., aqueous bromine or aqueous bromide) (collectively 702) and is substantially chemically inert in the presence of an electrolyte. In some embodiments, the carbon material comprises carbon black or other furnace process carbon. Suitable carbon black materials include, but are not limited to, Cabot XC72R, Akzo-NobelKetjenblack EC600JD and other matte black mixtures of conductive heating furnace process carbon black. In some embodiments, the carbon material may also include other components, including but not limited to PTFE binder, carbon fiber and deionized water. For example, the carbon material has a water content of less than 50% by weight (e.g., about 0.01% by weight to about 30% by weight) by weight of the carbon material. In some instances, the carbon material includes PTFE (e.g., about 0.5% by weight to about 5% by weight by weight of the carbon material).

[0261] In certain embodiments, the carbon material is molded into a certain size and shape so that the carbon material can be at least partially nested by the cathode holder. In some instances, the carbon material can be in the form of one or more thin rectangular blocks. For example, the carbon material is shaped as one or more thin rectangular blocks with rounded corners so that the corners will not penetrate the separator when the cathode assembly is assembled. In certain embodiments, the carbon material can include a single solid block. In other embodiments, the carbon material can include one to five, one to three or one to two carbon blacks.

[0262] iii. Partition

[0263] The separator 222 that can be used in the electrochemical cell or battery pack of the present invention is capable of forming a porous barrier between the reduced surface of at least the pocket portion of the cathode holder and the carbon material. In some embodiments, the separator is formed of a conductive material that enables electron transport. In some embodiments, the separator is formed of a wettable woven fabric or a wettable non-woven fabric, either of which is conductive. In other embodiments, the separator is formed of a wettable woven fabric or a wettable non-woven fabric. And, in some instances, the woven or non-woven fabric includes a plurality of pores sized to allow electrolyte to pass therethrough while at least substantially restricting the passage of carbon material particles therethrough. In other embodiments, the separator is formed of a carbon cloth that includes a FM10ACC 100% activated woven carbon cloth with extremely large surface area (e.g., 1000-2000m 2 / g) and / or exhibit fast reaction and adsorption kinetics. In some embodiments, the separator is formed of graphite cloth.

[0264] In some embodiments, the separator 222 is interposed between at least a portion of the cathode holder and the carbon material. And, in other embodiments, the separator substantially encapsulates the carbon material such that the separator is interposed between the carbon material and substantially all of the pocket portion of the cathode holder, and the separator is interposed between at least a portion of the carbon material and at least a portion of the bipolar electrode plate. For example, the separator is interposed between at least a reduced surface of the cathode holder having a hole pattern (e.g., a plurality of holes 227) and the carbon material.

[0265] 2. Terminal assembly

[0266] Another aspect of the present invention provides a terminal assembly for a bipolar electrochemical cell or battery. Figures 12 to 17The terminal assembly 104 of the present invention includes a conductive cup-shaped member 310, which includes a terminal wall 312, a side wall 304, and an edge 306 separated from the terminal wall by the side wall. The terminal 308 of the bipolar electrochemical cell or battery pack is connected to be electrically connected to the terminal wall 312 of the conductive cup-shaped member 310. In some embodiments, the terminal 308 comprises brass (for example, the terminal is a brass plug that is electrically connected or in contact with the terminal wall). In some embodiments, the portion of the terminal wall 312 that contacts the terminal 308 comprises copper. In these embodiments, the terminal wall can be formed of titanium and include a copper plate that is operable to contact the terminal formed of copper and electrically connect it to the terminal wall of the conductive cup-shaped member.

[0267] The terminal assembly further includes a terminal end plate 302 having an inner surface 318 and an outer surface 316 that are at least substantially coplanar with the terminal wall and joined to an edge at the outer surface 316. The terminal end plate 302 can be shaped to include any of the features present in the bipolar electrode plate, including, but not limited to, a titanium material coated with a titanium carbide material, a through hole, a rough inner surface, etc. The edge of the cup-shaped member is joined to the terminal end plate 302 so that the edge is approximately in the center of the electrochemically active area 322 of the terminal end plate. In some embodiments, the electrochemically active area 322 corresponds to an area extending between the inner and outer surfaces of the terminal end plate that is chemically or electrically connected to an adjacent bipolar electrode during the charge and discharge cycle of the electrochemical cell or battery pack. In these embodiments, the electrochemically active area of ​​the terminal end plate associated with the negative cathode terminal of the battery corresponds to the area surrounded by the cathode assembly disposed on the inner surface of the terminal end plate (e.g., the terminal cathode end plate), or is defined by it. The electrochemically active area of ​​the terminal end plate associated with the positive anode terminal of the battery can correspond to the area on its inner surface that is opposite to the cathode assembly disposed on the front surface of the adjacent bipolar electrode plate and forms a zinc metal layer when the battery (terminal anode assembly) is charged. In some embodiments, at least a portion of the inner surface of the terminal end plate of the terminal anode assembly (e.g., at least the chemically active area) is a rough surface.

[0268] Fig.14 A top view of a terminal end plate is provided showing the electrochemically active area of ​​the terminal end plate including a first surface area 326 enclosed within a dashed ellipse 306 corresponding to the outer perimeter of the rim and a remaining second surface area 324 defined by the outer perimeter of the rim 306 and the peripheral edge of the electrochemically active area 322. Fig.14 The conductive cup-shaped member 310 is removed in order to show the first surface area. Thus, when the conductive cup-shaped member is bonded to the outer surface of the terminal end plate, the first surface area is surrounded by the edge. The first 326 and second 324 surface areas are substantially equal.

[0269] In some embodiments, the edge is generally elliptical and has a major axis A MAJ and the short axis A perpendicular to the long axis MIN The major axis and the minor axis intersect at the center of the edge and also the center of the electrochemically active area. As used herein, a substantially elliptical edge refers to an edge having a substantially rectangular shape with rounded or otherwise curved and rounded corners. In some embodiments, the edge is substantially rectangular. Fig.15 Provides along Fig.13 A cross-sectional view taken along line 15-15 showing the major radius R of the edge MAJ is substantially equal to a first distance D1 extending from the outer periphery of the edge along the major axis to the peripheral edge of the electrochemically active area parallel to the minor axis, and Fig.13 Shows the short radius R of the edge MIN is substantially equal to a second distance D2 extending from the outer periphery of the edge along the minor axis to the peripheral edge of the electrochemically active area parallel to the major axis,

[0270] In some embodiments, the rim defines an opening to an interior region 330 that is defined by the interior surfaces of the terminal walls and sidewalls, and the exterior surface of the terminal end plate surrounds the opening to the interior region when joined to the rim.

[0271] In some embodiments, the edge is centered within the electrochemically active region of the end plate. In some embodiments, the edge is generally circular or generally elliptical.

[0272] In some embodiments, the sidewall is perpendicular or substantially perpendicular to the terminal wall and the edge. In other embodiments, the sidewall extends radially outward from the terminal wall to the edge.

[0273] In some embodiments, the edge is generally rounded. For example, Fig.16 A top perspective view of a terminal assembly is provided, the terminal assembly comprising a conductive cup-shaped member comprising a terminal wall, a side wall, and a generally circular edge 306' separated from the terminal wall by the side wall. In these embodiments, the radius R1 of the edge is substantially equal to the distance D3 between the peripheral edge of the electrochemically active area 322 and the outer periphery of the edge.

[0274] refer to Fig.17 along Fig.13 The cross-sectional view taken along line 17-17 of FIG. 1 shows that the terminal assembly includes a conductive cup-shaped member, a terminal end plate, an optional frame member 114, and a bipolar electrode adjacent to the terminal assembly, wherein the bipolar electrode includes a cathode assembly 202 and a bipolar electrode plate 208. Fig.17and 23 In some embodiments, the frame member 114 includes a first side 614 and a second side 616, the first side being opposite to and receiving an inner surface 318 of the terminal end plate 302 on a side opposite to the conductive cup-shaped member 312. In some of these embodiments, the second side of the frame member is opposite to the cathode assembly 202 of the bipolar electrode, and the bipolar electrode includes a bipolar electrode plate 208, the bipolar electrode plate 208 including a front surface 212 secured to the second side 616 of the frame member, and a cathode assembly 202 located on the front surface of the bipolar electrode plate, the cathode assembly being interposed between the front surface of the bipolar electrode plate and the inner surface of the terminal end plate. In some embodiments, the electrochemically active area 322 located at the inner surface of the terminal end plate is opposite to the cathode assembly located on the front surface of the bipolar electrode plate, and includes a size and shape substantially the same as a size and shape of the cathode assembly. Reference has been made above to Figure 3 and 4B As discussed in greater detail, cathode assembly 202 includes cathode holder 216, separator 222, and carbon material 224 located on the front surfaces 212, 212' of the bipolar electrode plates.

[0275] In some embodiments, the terminal assembly is a terminal cathode assembly, wherein the terminal cathode assembly includes a terminal end plate 302 having an electrochemically active area, a conductive cup-shaped member (such as any of the cup-shaped members described herein) disposed on the outer surface of the terminal end plate and approximately centered in the chemically active area, and a cathode assembly (such as any of the cathode assemblies described herein) disposed on the inner surface of the terminal end plate.

[0276] In some embodiments, the terminal assembly includes a terminal anode assembly, wherein the terminal anode assembly includes a terminal end plate having an electrochemically active region, a conductive cup-shaped member (such as any of the cup-shaped members described herein) disposed on an outer surface of the terminal end plate and approximately centered in the chemically active region, and wherein the terminal anode assembly is devoid of a cathode assembly.

[0277] In some embodiments, the edge of the conductive cup-shaped member is joined to the outer surface of the terminal end plate by welding or adhesive. In some instances, the adhesive is conductive. Examples of suitable conductive adhesives include graphite-filled adhesives (e.g., graphite-filled epoxy, graphite-filled silicone, graphite-filled elastomer, or any combination thereof), nickel-filled adhesives (e.g., nickel-filled epoxy), silver-filled adhesives (e.g., silver-filled epoxy), copper-filled adhesives (e.g., copper-filled epoxy), any combination thereof, and the like.

[0278] In some embodiments, the conductive cup-shaped member is composed of at least one of a copper alloy, a copper / titanium cladding, aluminum, and a conductive ceramic. For example, the inner surface of the terminal wall and the side wall comprises copper. In other examples, the outer surface of the terminal wall and the side wall comprises at least one of copper, titanium, and a conductive ceramic.

[0279] In some embodiments, at least one of the conductive cup-shaped member or the terminal end plate comprises titanium. In some embodiments, at least one of the conductive cup-shaped member or the terminal end plate comprises a titanium material coated with a titanium carbide material.

[0280] In some embodiments, the conductive cup-shaped member comprises a first metal and the end plate comprises a second metal.

[0281] In some embodiments, the edge includes a flange 328 extending radially outward from the side wall ( Fig.15 ).

[0282] Reference again Fig.15 The electrical characteristics of an exemplary terminal assembly for a zinc-halogen electrochemical cell or battery during operation (e.g., charging or discharging) thereof are summarized according to the following expression:

[0283] V A ≈V E ≈V C Expression 1

[0284] V D ≈V B Expression 2

[0285] V F ≈V G Expression 3

[0286] ΔV G-D ≈ΔV F-B >>ΔV H-G ≈ΔV F-H Expression 4

[0287] ΔV G-D ≈ΔV F-B >>ΔV B-C ≈ΔV D-C Expression 5

[0288] B and D indicate two electrical contact points between the edge of the cup-shaped member and the first surface of the bipolar end plate. H indicates the antisymmetric center of the conductive cup-shaped member, and C indicates the overlap of H on the first surface of the bipolar end plate such that the contact points along the minor axis A MIN Line CH extending and connecting C and H is normal to the first surface of the end plate. F and G identify the intersections where terminal wall 312 and side wall 304 meet, while A and E identify opposite peripheral edges of electrochemically active area 322.

[0289] The charge V at A A Approximately equal to the charge V at E E and the charge V at C C The charge V at D D Approximately equal to the charge V at B B . The charge V at F F Equal to the charge V at G G The potential difference or voltage ΔV from G to D G-D Approximately equal to the voltage ΔV from F to B F-B , the voltage from H to G is ΔV H-G Approximately equal to the voltage ΔV from F to H F-H , and ΔV G-D and ΔV F-B Generally larger than ΔV H-G and ΔV F-H . And, the voltage ΔV G-D and ΔV F-B Substantially greater than the voltage ΔV from B to C B-C and the voltage ΔV from D to C D-C .

[0290] Since the voltage from G to D and the voltage from F to B (i.e., ΔV G-D and ΔV F-B ) is substantially greater than the voltage from H to G and the voltage from F to H (i.e., ΔV H-G and ΔV F-H ), the current discharged from the terminals of the terminal assembly of the present invention is generally more uniform than the discharge current from a conventional bipolar battery having terminals directly attached to the end plates.

[0291] 3. Zinc-halide electrolyte

[0292] In the electrochemical cells and batteries of the present invention, an aqueous electrolyte (i.e., a zinc-halide electrolyte) is interposed between the inner surface of the terminal end plate, the cathode assembly, the front surface of the bipolar electrode, and the inner surface of the frame if present. In these embodiments, when the electrochemical cell or battery is charged, the bromide anions at the surface of the cathode holder of the cathode assembly, which are exposed to the electrolyte, are oxidized to bromine. Conversely, during discharge, the bromine is reduced to bromide anions. The conversion 232 between bromine and bromide anions at or near the cathode holder of the cathode assembly can be expressed as follows:

[0293] Br2+2e - →2Br - .

[0294] The present invention provides an aqueous electrolyte that can be used in a flowing or non-flowing (i.e., static) rechargeable zinc-halogen electrochemical cell or battery. In these cells or batteries, zinc bromide, zinc chloride, or any combination of the two is present in the electrolyte as the electrochemically active material.

[0295] One aspect of the present invention provides an electrolyte for use in a secondary zinc-bromine electrochemical cell (e.g., a static cell), comprising about 30 wt % to about 40 wt % ZnCl2 or ZnBr2, about 5 wt % to about 15 wt % KBr, about 5 wt % to about 15 wt % KCl, and one or more quaternary ammonium agents, wherein the electrolyte comprises about 0.5 wt % to about 10 wt % of the one or more quaternary ammonium agents.

[0296] In some embodiments, the electrolyte comprises about 4 wt % to about 12 wt % (e.g., about 6 wt % to about 10 wt %) potassium bromide (KBr). In some embodiments, the electrolyte comprises about 8 wt % to about 12 wt % potassium bromide (KBr).

[0297] In some embodiments, the electrolyte comprises about 4 wt % to about 12 wt % (e.g., about 6 wt % to about 10 wt %) potassium chloride (KCl). In some embodiments, the electrolyte comprises about 8 wt % to about 14 wt % potassium chloride (KCl). In some embodiments, the electrolyte comprises about 11 wt % to about 14 wt % potassium chloride (KCl).

[0298] In some embodiments, the electrolyte further comprises about 0.5 wt % to about 10 wt % (e.g., about 1 wt % to about 7.5 wt %) of glyme. In some embodiments, the glyme comprises monoglyme, diglyme, triglyme, tetraglyme, pentaglyme, hexaglyme, or any combination thereof. For example, the glyme comprises tetraglyme. In other instances, the electrolyte comprises about 1 wt % to about 5 wt % of tetraglyme.

[0299] In some embodiments, the electrolyte further comprises about 0.05 wt % to about 4 wt % (e.g., about 0.1 wt % to about 1 wt %) of an ether. In some embodiments, the ether is a crown ether, DME-PEG, dimethyl ether, or any combination thereof. In another embodiment, the ether is a crown ether.

[0300] In some embodiments, the electrolyte further comprises about 0.5 wt % to about 2.5 wt % (e.g., about 1 wt % to about 2.25 wt %) of DME-PEG or dimethyl ether. In some examples, the DME-PEG has an average molecular weight (e.g., number average molecular weight M) of about 350 amu to about 3000 amu. n). In other examples, the DME-PEG has an average molecular weight of about 1200 amu to about 3000 amu. And, in other examples, the electrolyte further comprises about 5 wt % to about 10 wt % of DME-PEG, wherein the DME-PEG has an average molecular weight (e.g., number average molecular weight M) of about 1500 amu to about 2500 amu (e.g., about 2000 amu). n ).

[0301] In some embodiments, the ether is a crown ether. For example, the crown ether is 18-crown-6. For example, the crown ether is 15-crown-5. For example, the crown ether is 12-crown-4.

[0302] In some embodiments, the electrolyte further comprises about 0.1 wt % to about 1.0 wt % of an alcohol, wherein the alcohol is substantially miscible in water. For example, the alcohol comprises C 1-4 Alcohol. In other examples, the alcohol includes methanol, ethanol, 1-propanol (i.e., n-propanol), 2-propanol (i.e., isopropanol), 1-butanol (i.e., n-butanol), sec-butanol, isobutanol, tert-butanol, 1-pentanol, or any combination thereof. And in some examples, the electrolyte further comprises about 0.25 wt % to about 0.75 wt % of tert-butanol.

[0303] In some embodiments, the electrolyte further comprises about 0.25 wt % to about 5 wt % (e.g., about 0.5 wt % to about 4 wt %) of C 1-10 In some examples, the electrolyte further comprises about 0.25 wt % to about 5 wt % (e.g., about 0.5 wt % to about 4 wt %) of a substituted ethylene glycol or substituted propylene glycol. In some examples, the glycol comprises ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, hexylene glycol, or any combination thereof. Also, in some examples, the electrolyte further comprises about 0.25 wt % to about 2.5 wt % of neopentyl glycol.

[0304] One aspect of the present invention provides an electrolyte for use in a secondary static zinc-bromine electrochemical cell (e.g., a static cell), comprising about 30 wt % to about 50 wt % (e.g., about 35 wt % to about 47.5 wt % or about 37 wt % to about 46 wt %) of ZnBr2, about 22.5 wt % to about 40 wt % (e.g., about 23.75 wt % to about 38 wt % or about 24 wt % to about 36 wt %) of H2O, about 3.00 wt % to about 9.5 wt % of H2O, and about 1.5 wt % of H2O. (e.g., about 4.00 wt% to about 8.5 wt%, about 3.00 wt% to about 8.5 wt%, or about 4.1 wt% to about 8 wt%) of KBr, about 7.75 wt% to about 14.0 wt% (e.g., about 7.9 wt% to about 13.25 wt% or about 8 wt% to about 13 wt%) of KCl, about 0.25 wt% to about 2.25 wt% (e.g., about 0.35 wt% to about 2.0 wt% or about 0.5 wt% to about 2 wt%) of MPEG 2K, about 0.075 wt% to about 1.25 wt% (e.g., about 0.1 wt% to about 1 wt%) of MPEG 1K, about 0.35 wt% to about 2.75 wt% (e.g., about 0.4 wt% to about 2.65 wt% or about 0.5 wt% to about 2.5 wt%) of neopentyl glycol.

[0305] In some embodiments, the one or more quaternary ammonium agents include those having the formula N + (R A )(R B )3X - One or more quaternary ammonium agents, wherein R A C 1-6 Alkyl (e.g., methyl, ethyl, propyl, butyl, etc.), R B C 1-6 alkyl (e.g., methyl, ethyl, propyl, butyl, etc.), and X - Br - or Cl - In some embodiments, the one or more quaternary ammonium agents are selected from at least one of triethylmethylammonium chloride, tetraethylammonium bromide and / or trimethylpropylammonium bromide. In some embodiments, the electrolyte comprises up to 5 (e.g., 1, 2, 3, 4, or 5) different quaternary ammonium agents. For example, the electrolyte comprises triethylmethylammonium chloride. In other examples, the electrolyte comprises triethylmethylammonium chloride and tetraethylammonium bromide. And, in some examples, the electrolyte comprises triethylmethylammonium chloride, tetraethylammonium bromide and trimethylpropylammonium bromide.

[0306] In one example, the electrolyte includes about 30 wt % to about 50 wt % (e.g., about 35 wt % to about 47.5 wt % or about 37 wt % to about 46 wt %) of ZnBr2, about 22.5 wt % to about 40 wt % (e.g., about 23.75 wt % to about 38 wt % or about 24 wt % to about 36 wt %) of H2O, about 3.00 wt % to about 9.5 wt % (e.g., about 4.00 wt % to about 8.5 wt %, about 3.00 wt % to about 8.5 wt %, or about 4.1 wt % to about 8 wt %) of KBr, about 7.75 wt % to about 14.0 wt % (e.g., about 7.9 wt % to about 13.25 wt % or about 8 wt % to about 13 wt %) of KCl, about 0.25 wt % to about 2.25 wt % (e.g., about 0.35 wt % to about 2.0 wt % or about 0.5 wt % to about 2 wt %) of MPEG 2K, about 0.075 wt % to about 1.25 wt % (e.g., about 0.1 wt % to about 1 wt %) of MPEG 1K, about 0.35 wt % to about 2.75 wt % (e.g., about 0.4 wt % to about 2.65 wt % or about 0.5 wt % to about 2.5 wt %) of neopentyl glycol, about 3.5 wt % to about 15 wt % (e.g., about 4 wt % to about 13 wt %) of a first quaternary ammonium agent (e.g., triethylmethylammonium chloride), and about 0.35 wt % to about 3.75 wt % of a second quaternary ammonium agent (e.g., tetraethylammonium bromide).

[0307] In another example, the electrolyte includes about 30 wt % to about 50 wt % (e.g., about 35 wt % to about 47.5 wt % or about 37 wt % to about 46 wt %) of ZnBr2, about 22.5 wt % to about 40 wt % (e.g., about 23.75 wt % to about 38 wt % or about 24 wt % to about 36 wt %) of H2O, about 3.00 wt % to about 9.5 wt % (e.g., about 4.00 wt % to about 8.5 wt %, about 3.00 wt % to about 8.5 wt %, or about 4.1 wt % to about 8 wt %) of KBr, about 7.75 wt % to about 14.0 wt % (e.g., about 7.9 wt % to about 13.25 wt % or about 8 wt % to about 13 wt %) of KCl, about 0.25 wt % to about 2.25 wt % (e.g., about 0.35 wt % to about 2.0 wt % or about 0.5 wt % to about 2 wt %) of MPEG 2K, about 0.075 wt% to about 1.25 wt% (e.g., about 0.1 wt% to about 1 wt%) of MPEG 1K, about 0.35 wt% to about 2.75 wt% (e.g., about 0.4 wt% to about 2.65 wt% or about 0.5 wt% to about 2.5 wt%) of neopentyl glycol, about 3.5 wt% to about 15 wt% (e.g., about 4 wt% to about 13 wt%) of a first quaternary ammonium agent (e.g., triethylmethylammonium chloride), about 0.35 wt% to about 3.75 wt% of a second quaternary ammonium agent (e.g., tetraethylammonium bromide), and about 0.35 wt% to about 2.75 wt% (e.g., about 0.5 wt% to about 2.5 wt%) of neopentyl glycol.

[0308] And, in another example, the electrolyte includes about 30 wt % to about 50 wt % (e.g., about 35 wt % to about 47.5 wt % or about 37 wt % to about 46 wt %) of ZnBr2, about 22.5 wt % to about 40 wt % (e.g., about 23.75 wt % to about 38 wt % or about 24 wt % to about 36 wt %) of H2O, about 3.75 wt % to about 9.5 wt % (e.g., about 4 wt % to about 8.5 wt % or about 4.1 wt % to about 8 wt %) of KBr, about 7.75 wt % to about 13.5 wt % (e.g., about 7.9 wt % to about 13.25 wt % or about 8 wt % to about 13 wt %) of KCl, about 0.25 wt % to about 2.25 wt % (e.g., about 0.35 wt % to about 2.0 wt % or about 0.5 wt % to about 2 wt %) of MPEG 2K, about 0.075 wt % to about 1.25 wt % (e.g., about 0.1 wt % to about 1 wt %) of MPEG1K, about 0.35 wt % to about 2.75 wt % (e.g., about 0.4 wt % to about 2.65 wt % or about 0.5 wt % to about 2.5 wt %) of neopentyl glycol, about 3.5 wt % to about 15 wt % (e.g., about 4 wt % to about 13 wt %) of a first quaternary ammonium agent (e.g., triethylmethylammonium chloride), about 0.35 wt % to about 3.75 wt % of a second quaternary ammonium agent (e.g., tetraethylammonium bromide), about 0.35 wt % to about 2.75 wt % (e.g., about 0.5 wt % to about 2.5 wt %) of neopentyl glycol, about 5 ppm to about 20 ppm of tin (e.g., SnCl2 or any hydrate thereof), and about 5 ppm to about 20 ppm of indium (e.g., InCl3 or any hydrate thereof).

[0309] In some embodiments, the one or more quaternary ammonium agents are salts having Formula I.

[0310]

[0311] in

[0312] is saturated, partially unsaturated, or fully unsaturated;

[0313] X1, X2, X3, X4 and X5 are each independently selected from carbon, oxygen and nitrogen, provided that at least one of X1, X2, X3, X4 and X5 is nitrogen;

[0314] Each R is independently hydrogen, alkyl, cycloalkyl, aryl, arylalkyl, heterocycloalkyl or heteroaryl, wherein each R is independently and optionally substituted with halo, -CN, -NO2, -Q2, -OQ2, -S(O) z Q2, -S(O) zN(Q2)2, -N(Q2)2, -C(O)OQ2, -C(O)Q2, -C(O)N(Q2)2, -C(O)N(Q2)(OQ2), -N(Q2)C(O)Q2, -N(Q2)C(O)N(Q2)2, -N(Q2)C(O)OQ2 or -N(Q2)S(O) z Q2 replaced;

[0315] each Q2 is independently hydrogen, alkyl, cycloalkyl, aryl, arylalkyl, heterocycloalkyl or heteroaryl, each optionally substituted with 1 to 3 Q3 substituents;

[0316] Each Q3 is independently halo, oxo, CN, NO2, CF3, OCF3, OH, -S(O) z (C 1-6 Alkyl), -N(C 1-6 Alkyl)2, -COO(C 1-6 alkyl), -C(O)(C 1-6 Alkyl), -O(C 1-6 alkyl), or C substituted with 1 to 3 substituents 1-6 Alkyl, wherein the 1 to 3 substituents are selected from halo, oxo, -CN, -NO2, -CF3, -OCF3, -OH, -SH, -S(O) z H, -NH2 or -COOH;

[0317] m is 0, 1, 2, 3, 4 or 5;

[0318] n is 0, 1 or 2;

[0319] z is 0, 1 or 2; and

[0320] Y is an anion.

[0321] In one embodiment, one or two of X1, X2, X3, X4 and X5 are nitrogen, and the others are carbon. In another embodiment, one of X1, X2, X3, X4 and X5 is nitrogen, and the others are carbon. In another embodiment, two of X1, X2, X3, X4 and X5 are nitrogen, and the others are carbon. In yet another embodiment, is selected from the group consisting of pyridine, pyrimidine, pyrazine, piperazine, piperidine, morpholine, 1,3-oxazinane, 1,2-oxazinane, pyrrolidine, pyrrole, pyrazole, imidazole, oxazole, isoxazole, 1,2,3-oxadiazole, 1,3,4-oxadiazole, 1,2,3-triazole, 1,2,4-triazole, 1,2,3,4-oxatriazole, 1,2,3,5-oxatriazole, 1,2,4,5-oxatriazole and tetrazole.

[0322] In one embodiment, is selected from the group consisting of pyridine, pyrimidine, pyrazine, piperazine, piperidine, morpholine, 1,3-oxazinane and 1,2-oxazinane. is selected from pyridine, pyrimidine and pyrazine. In another embodiment, It's pyridine.

[0323] In one embodiment, is selected from piperidine, morpholine, 1,3-oxazinane and 1,2-oxazinane. In another embodiment, is selected from piperidine and morpholine. In one embodiment, In one embodiment, For morpholine.

[0324] In one embodiment, is selected from the group consisting of pyrrolidine, pyrrole, pyrazole, imidazole, oxazole, isoxazole, 1,2,3-oxadiazole, 1,3,4-oxadiazole, 1,2,3-triazole, 1,2,4-triazole, 1,2,3,4-oxtriazole, 1,2,3,5-oxtriazole, 1,2,4,5-oxtriazole and tetrazole. In another embodiment, is selected from pyrrole, pyrazole and imidazole. In one embodiment, In one embodiment, In one embodiment, In one embodiment, It is pyrrolidine.

[0325] In one embodiment, n is 1. In another embodiment, n is 0.

[0326] In one embodiment, each R is independently alkyl or cycloalkyl, wherein each R is independently and optionally substituted by halo, -CN, -NO2, -OQ2, -S(O) z Q2, -S(O) z N(Q2)2, -N(Q2)2, -C(O)OQ2, -C(O)Q2, -C(O)N(Q2)2, -C(O)N(Q2)(OQ2), -N(Q2)C(O)Q2, -N(Q2)C(O)N(Q2)2, -N(Q2)C(O)OQ2, -N(Q2)S(O) zQ2, or optionally with 1 to 3 Q3substituents substituted heterocycloalkyl or alkyl.In another embodiment, each R is independently alkyl or cycloalkyl, wherein each R independently and optionally with halo, heterocycloalkyl ,-CN ,-NO2,-OQ2,-N(Q2)2,-C(O)OQ2,-C(O)Q2 or-C(O)N(Q2)2 replace.In another embodiment, each R is alkyl, which independently and optionally with halo, heterocycloalkyl ,-CN ,-NO2,-OQ2,-N(Q2)2,-C(O)OQ2,-C(O)Q2 or-C(O)N(Q2)2 replace.In another embodiment again, each R is alkyl, which independently and optionally with halo, heterocycloalkyl ,-CN ,-NO2,-N(Q2)2 or-C(O)N(Q2)2 replace. In yet another embodiment, each R is alkyl, which is independently and optionally substituted with halo or heterocycloalkyl.

[0327] In another embodiment, each R is alkyl substituted with heterocycloalkyl. In yet another embodiment, R is alkyl substituted with pyrrolidine. In yet another embodiment, R is propyl substituted with heterocycloalkyl. In yet another embodiment, R is propyl substituted with pyrrolidine.

[0328] In one embodiment, each R is an unsubstituted alkyl group. For example, R is an unsubstituted linear or branched C 1-20 In another embodiment, R is selected from methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, 2-ethylhexyl, octyl, nonyl, decyl, dodecyl and hexadecyl. In one embodiment, R is selected from methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl and hexadecyl. In one embodiment, R is methyl. In one embodiment, R is ethyl. In one embodiment, R is propyl. In one embodiment, R is butyl. In one embodiment, R is pentyl. In one embodiment, R is hexyl. In one embodiment, R is heptyl. In one embodiment, R is octyl. In one embodiment, R is dodecyl. In one embodiment, R is nonyl. In one embodiment, R is decyl. In one embodiment, R is dodecyl. In one embodiment, R is hexadecyl.

[0329] In one embodiment, Y is an anion selected from fluoride, chloride, bromide, iodide, arsenate, phosphate, arsenite, hydrogen phosphate, dihydrogen phosphate, sulfate, nitrate, hydrogen sulfate, nitrite, thiosulfate, sulfite, perchlorate, iodate, chlorate, bromate, chlorite, hypochlorite, chlorate, perchlorate, hypobromite, bromite, bromate, perbromate, carbonate, chromate, bicarbonate (bicarbonate), dichromate, acetate, formate, cyanide, amide, cyanate, peroxide, thiocyanate, oxalate, hydroxide and permanganate. In another embodiment, Y is a monovalent anion selected from fluoride, chloride, bromide, iodide, dihydrogen phosphate, nitrate, perchlorate, hypochlorite, bicarbonate (bicarbonate), acetate, formate, cyanide and hydroxide. In yet another embodiment, Y is a divalent anion selected from hydrogen phosphate, sulfate, and carbonate. In yet another embodiment, Y is selected from fluoride, chloride, bromide, and iodide. In one embodiment, Y is chloride. In one embodiment, Y is bromide. In one embodiment, Y is iodide.

[0330] In some embodiments, the one or more quaternary ammonium agents are salts having Formula Ia, Formula Ib, Formula Ic, Formula Id, or Formula Ie.

[0331]

[0332] in

[0333] Each R, R' and R" is independently hydrogen, alkyl, cycloalkyl, aryl, arylalkyl, heterocycloalkyl or heteroaryl, wherein each R, R' and R" is independently and optionally substituted by halo, -CN, -NO2, -OQ2, -S(O) z Q2, -S(O) z N(Q2)2, -N(Q2)2, -C(O)OQ2, -C(O)Q2, -C(O)N(Q2)2, -C(O)N(Q2)(OQ2), -N(Q2)C(O)Q2, -N(Q2)C(O)N(Q2)2, -N(Q2)C(O)OQ2, -N(Q2)S(O) z Q2, or heterocycloalkyl or alkyl optionally substituted with 1 to 3 Q3 substituents;

[0334] each Q2 is independently hydrogen, alkyl, cycloalkyl, aryl, arylalkyl, heterocycloalkyl or heteroaryl, each optionally substituted with 1 to 3 Q3 substituents;

[0335] Each Q3 is independently halo, oxo, CN, NO2, CF3, OCF3, OH, -S(O) z (C 1-6 Alkyl), -N(C1-6 Alkyl)2, -COO(C 1-6 alkyl), -C(O)(C 1-6 Alkyl), -O(C 1-6 alkyl), or C optionally substituted with 1 to 3 substituents 1-6 Alkyl, wherein the 1 to 3 substituents are selected from halo, oxo, -CN, -NO2, -CF3, -OCF3, -OH, -SH, -S(O) z H, -NH2 or -COOH;

[0336] z is 0, 1 or 2; and

[0337] Y is an anion.

[0338] In some embodiments of Formulas Ia to Ie, each R, R' and R" is independently alkyl or cycloalkyl, wherein each R, R' and R" is independently and optionally substituted with halo, -CN, -NO2, -OQ2, -S(O) z Q2, -S(O) z N(Q2)2, -N(Q2)2, -C(O)OQ2, -C(O)Q2, -C(O)N(Q2)2, -C(O)N(Q2)(OQ2), -N(Q2)C(O)Q2, -N(Q2)C(O)N(Q2)2, -N(Q2)C(O)OQ2, -N(Q2)S(O) z Q2, or optionally with 1 to 3 Q3 substituents substituted heterocycloalkyl or alkyl. In another embodiment, each R, R 'and R "is independently alkyl or cycloalkyl, wherein each R, R 'and R "is independently and optionally with halo, heterocycloalkyl, -CN, -NO2, -OQ2, -N (Q2)2, -C (O) OQ2, -C (O) Q2, or -C (O) N (Q2)2 replace. In another embodiment, each R, R' and R" is independently alkyl, which is independently and optionally substituted with halo, heterocycloalkyl, -CN, -NO2, -OQ2, -N(Q2)2, -C(O)OQ2, -C(O)Q2, or -C(O)N(Q2)2. In yet another embodiment, each R, R' and R" is independently alkyl, which is independently and optionally substituted with halo, heterocycloalkyl, -CN, -NO2, -N(Q2)2, or -C(O)N(Q2)2.

[0339] In one embodiment, each R, R' and R" is independently unsubstituted alkyl. In another embodiment, each R, R' and R" is independently selected from methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, 2-ethylhexyl, octyl, nonyl, decyl, dodecyl and hexadecyl. In one embodiment, each R, R' and R" is independently selected from methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl and hexadecyl.

[0340] In some embodiments of Formulas Ia to Ie, Y is selected from fluoride, chloride, bromide, iodide, arsenate, phosphate, arsenite, hydrogen phosphate, dihydrogen phosphate, sulfate, nitrate, hydrogen sulfate, nitrite, thiosulfate, sulfite, perchlorate, iodate, chlorate, bromate, chlorite, hypochlorite, hypobromite, carbonate, chromate, bicarbonate (bicarbonate), dichromate, acetate, formate, cyanide, amide, cyanate, peroxide, thiocyanate, oxalate, hydroxide and permanganate. In another embodiment, Y is a monovalent anion selected from fluoride, chloride, bromide, iodide, dihydrogen phosphate, nitrate, perchlorate, hypochlorite, bicarbonate (bicarbonate), acetate, formate, cyanide and hydroxide. In yet another embodiment, Y is selected from a divalent anion selected from hydrogen phosphate, sulfate and carbonate. In yet another embodiment, Y is selected from fluoride, chloride, bromide, and iodide. In one embodiment, Y is chloride. In one embodiment, Y is bromide. In one embodiment, Y is iodide.

[0341] In some embodiments of Formulas Ia to Ie, k is 0 or 1. In another embodiment, k is 0. In yet another embodiment, k is 1.

[0342] In some embodiments of Formula Ia, each R and R' is independently selected from methyl, ethyl, butyl, and hexyl. In another embodiment, k is 1; R' is selected from ethyl, butyl, and hexyl; and R is methyl. In yet another embodiment, k is 0 and R' is selected from ethyl, butyl, and hexyl.

[0343] In one embodiment, the salt of Formula Ia is selected from 1-ethyl-3-methylpyridinium bromide, 1-ethyl-2-methylpyridinium bromide, 1-butyl-3-methylpyridinium bromide, 1-butyl-4-methylpyridinium bromide, and 1-hexylpyridinium bromide.

[0344] In some embodiments of Formula Ib, each R, R', and R" is independently selected from methyl and propyl.

[0345] In one embodiment, the salt of Formula Ib is 1-methyl-1-propylpiperidinium bromide.

[0346] In some embodiments of Formula Ic, each R, R' and R" is independently selected from methyl, ethyl and butyl. In another embodiment, k is 0.

[0347] In one embodiment, the salt of Formula Ic is selected from N-methyl-N-ethylmorpholinium bromide and N-methyl-N-butylmorpholinium bromide.

[0348] In some embodiments of Formula Id, each R, R' and R" is independently selected from methyl, ethyl, butyl, hexyl, octyl and decyl. In another embodiment, k is 1 and R is methyl.

[0349] In one embodiment, the salt of formula Id is selected from 1-ethyl-3-methylimidazolium bromide, 1-butyl-3-methylimidazolium bromide, 1-ethyl-2,3-dimethylimidazolium bromide, 1-decyl-3-methylimidazolium bromide, 1-butyl-2,3-dimethylimidazolium bromide, 1-methyl-3-octylimidazolium bromide and 1-methyl-3-hexylimidazolium bromide.

[0350] In some embodiments of Formula Ie, each R, R' and R" is independently selected from methyl, ethyl, propyl, butyl, pentyl and hexyl. In another embodiment, k is 0 and each R' and R" is independently alkyl, which is optionally substituted with cycloalkyl or halo. In another embodiment, k is 0 and each R' and R" is independently selected from methyl, ethyl, propyl, butyl, pentyl, hexyl, 2-chloroethyl, or 3-(methylpyrrolidinium)propyl.

[0351] In one embodiment, the salt of Formula Ie is selected from N-methyl-N-ethylpyrrolidinium bromide, N-ethyl-N-propylpyrrolidinium bromide, N-propyl-N-butylpyrrolidinium bromide, N-methyl-N-butylpyrrolidinium bromide, N-ethyl-N-(2-chloroethyl)pyrrolidinium bromide, N-methyl-N-hexylpyrrolidinium bromide, N -methyl-N-pentylpyrrolidinium bromide, N-ethyl-N-pentylpyrrolidinium bromide, N-ethyl-N-butylpyrrolidinium bromide, N-butyl-N-pentylpyrrolidinium bromide, N-methyl-N-propylpyrrolidinium bromide, trimethylene-bis(N-methylpyrrolidinium) dibromide, and N-propyl-N-pentylpyrrolidinium bromide.

[0352] In some embodiments, the one or more quaternary ammonium agents comprise a compound having the formula A reagent wherein R1, R2, R3 and R4 are each independently hydrogen or an alkyl group (e.g., C 1-6 Alkyl group or C 1-4alkyl group), and Y is an anion as defined herein. In some embodiments, the one or more quaternary ammonium agents include ammonium halides (e.g., NH4Br, NH4Cl, or any combination thereof), tetraalkylammonium halides (e.g., tetramethylammonium bromide, tetramethylammonium chloride, triethylmethylammonium chloride, tetraethylammonium bromide, tetraethylammonium chloride, trimethylpropylammonium bromide, combinations thereof, etc.), heterocyclic ammonium halides (e.g., N-methyl-N-ethylpyrrolidinium chloride, N-ethyl-N-methylpyrrolidinium halide, combinations thereof, etc.), or any combination thereof. In some embodiments, the one or more quaternary ammonium agents include a quaternary ammonium agent selected from the group consisting of ammonium chloride, ammonium bromide, tetraethylammonium bromide, trimethylpropylammonium bromide, N-methyl-N-ethylmorpholinium bromide, N-ethyl-N-methylmorpholinium bromide, N-methyl-N-butylmorpholinium bromide, N-methyl-N-ethylpyrrolidinium bromide, N,N,N-triethyl-N-propylammonium bromide, N-ethyl-N-propylpyrrolidinium bromide, N-propyl-N-butylpyrrolidinium bromide, N-methyl-N- In some embodiments, the electrolyte comprises about 1 wt % to about 5 wt % of one or more quaternary ammonium agents. In some embodiments, the electrolyte comprises about 3 wt % to about 7 wt % of one or more quaternary ammonium agents. Also, in some embodiments, the one or more quaternary ammonium agents include N-methyl-N-ethylmorpholinium bromide. In other examples, the electrolyte includes about 0.25 wt % to about 1.25 wt % of N-methyl-N-ethylmorpholinium bromide. Also, in some examples, the one or more quaternary ammonium agents include tetraethylammonium bromide, trimethylpropylammonium bromide, or any combination thereof. For example, the electrolyte includes about 1 wt % to about 5 wt % of tetraethylammonium bromide.

[0353] In some embodiments, the one or more quaternary ammonium agents include a quaternary ammonium agent selected from the group consisting of ammonium bromide complexes, imidazolium bromide complexes, pyrrolidinium bromide complexes, pyridinium bromide complexes, phosphonium bromide complexes, and morpholinium bromide complexes.

[0354] In some examples, the one or more quaternary ammonium agents include a quaternary ammonium agent selected from the group consisting of tetraethylammonium (TEA) bromide, N-ethyl-N-methylmorpholinium (MEM) bromide, trimethylpropylammonium bromide, 1-ethyl-3-methylimidazolium bromide, 1-butyl-3-methylimidazolium bromide, 1-butyl-1-methylpyrrolidinium bromide, 1-ethyl-3-methylpyridinium bromide, 1-ethyl-3-methylpyridinium bromide, 1-ethyl-2-methylpyridinium bromide, 1-methyl-1-propylpiperidinium bromide, dodecyltrimethylammonium bromide, Methylammonium bromide, 1-ethyl-2,3-dimethylimidazolium bromide, 1-decyl-3-methylimidazolium bromide, 1-butyl-2,3-dimethylimidazolium bromide, 1-methyl-3-octylimidazolium bromide, 1-methyl-3-hexylimidazolium bromide, 1-butyl-3-methylpyridinium bromide, 1-butyl-4-methylpyridinium bromide, 1-hexylpyridinium bromide, triethylmethylammonium chloride, tetraethylphosphonium bromide, 1-methyl-1-propylpyrrolidinium bromide, hexyltrimethylammonium bromide, and hexadecyltriethylammonium bromide.

[0355] In some embodiments, the one or more quaternary ammonium agents include 1-ethyl-3-methylpyridinium bromide, 1-ethyl-2-methylpyridinium bromide, 1-butyl-3-methylpyridinium bromide, or 1-butyl-1-methylpyrrolidinium bromide. For example, the electrolyte includes about 1 wt % to about 5 wt % (e.g., about 1.5 wt % to about 4 wt %) of 1-ethyl-3-methylpyridinium bromide, 1-ethyl-2-methylpyridinium bromide, 1-butyl-3-methylpyridinium bromide, N-ethyl-N-methylmorpholinium bromide, or 1-butyl-1-methylpyrrolidinium bromide.

[0356] In some embodiments, the one or more quaternary ammonium agents include those having the formula N + (R A )(R B )3X - One or more quaternary ammonium agents, wherein R A C 1-6 Alkyl (e.g., methyl, ethyl, propyl, butyl, etc.), R B C 1-6 In some embodiments, R B is different from R A C 1-6 In some embodiments, the one or more quaternary ammonium agents are selected from triethylmethylammonium chloride and / or tetraethylammonium chloride.

[0357] In some examples, the one or more quaternary ammonium agents include a quaternary ammonium agent including at least one of 1-ethyl-4-methylpyridinium bromide, 1-ethyl-2-methylpyridinium bromide, triethylmethylammonium bromide, triethylmethylammonium chloride, triethylmethylammonium chloride, 1,1'-dioctadecyl-4-4'-bipyridinium dibromide, or 1-ethyl-4-methylpyridinium bromide.

[0358] In some embodiments, the one or more quaternary ammonium agents include hexadecyl triethylammonium bromide (CTAB), decyl triethylammonium bromide or dodecyl triethylammonium bromide. For example, the electrolyte includes about 0.01 wt % to about 1 wt % (e.g., about 0.05 wt % to about 0.5 wt %) of hexadecyl triethylammonium bromide (CTAB).

[0359] In some instances, one or more quaternary ammonium agents include tetraethylammonium bromide, trimethylpropylammonium bromide, or any combination thereof. For example, the electrolyte comprises from about 1 wt % to about 6 wt % (e.g., from about 1.5 wt % to about 5 wt %) of tetraethylammonium bromide. For example, the electrolyte comprises from about 1 wt % to about 5 wt % (e.g., from about 1.5 wt % to about 3.5 wt %) of trimethylpropylammonium bromide.

[0360] Without being bound by theory, it is believed that quaternary ammonium agents enhance electrochemistry by creating a buoyancy effect using bromine complexes formed with the quaternary ammonium agent. As bromide ions in the electrolyte pseudo-polymerize, they become heavier and sink to the bottom of the electrolyte volume, thereby reducing the dynamics in the cell. Quaternary ammonium agents that create a buoyancy effect help alleviate the problem, thereby carrying pseudo-polymerized bromide ions away from the bottom of the electrolyte volume and increasing the dynamics in the cell.

[0361] In some embodiments, the electrolyte further comprises less than 1 wt % of one or more additives selected from Sn, In, Ga, Al, Tl, Bi, Pb, Sb, Ag, Mn, Fe, or any combination thereof. For example, the electrolyte comprises less than 1 wt % of Sn and In.

[0362] In some embodiments, the electrolyte further comprises about 30% to about 50% by weight of water. In some embodiments, the electrolyte further comprises about 35% to about 45% by weight of water. In some instances, the water is demineralized until its impedance is greater than about 8 MΩ·cm (e.g., about 10 MΩ·cm or greater or greater than about 10 MΩ·cm). In other instances, the water is simply tap water.

[0363] In some embodiments, the electrolyte further comprises a sufficient amount of HBr to give the electrolyte a pH of about 2 to about 4 (about 2.5 to about 3.5). In some embodiments, the electrolyte further comprises about 0.1 wt % to about 2 wt % (e.g., about 0.3 wt % to about 1 wt %) HBr.

[0364] In some embodiments, the electrolyte further comprises about 0.1 wt % to about 2 wt % (e.g., about 0.3 wt % to about 1 wt %) of acetic acid. In alternative embodiments, the electrolyte comprises about 0.1 wt % to about 2 wt % of acetic acid, sodium acetate, potassium acetate, or any combination thereof.

[0365] In some embodiments, the electrolyte further comprises about 2 wt % to about 8 wt % (e.g., about 3 wt % to about 5 wt %) of citric acid monohydrate. In some embodiments, the electrolyte further comprises about 2 wt % to about 8 wt % (e.g., about 3 wt % to about 5 wt %) of potassium dihydrogen citrate monohydrate.

[0366] In some embodiments, the electrolyte further comprises about 2 wt % to about 8 wt % (e.g., about 3 wt % to about 5 wt %) of oxalic acid. In some embodiments, the electrolyte further comprises about 2 wt % to about 8 wt % (about 3 wt % to about 5 wt %) of oxalic acid.

[0367] In some embodiments, the electrolyte further comprises a stable additive. For example, the stable additive is acetic acid, sodium acetate, oxalic acid, sodium oxalate, citric acid, sodium citrate, 18-crown-6, dicyandiamide, succinic acid, sodium methanesulfonate, sodium propionate, sodium malonate, sodium caproate, sodium hexafluoroaluminate, sebacic acid, potassium trifluoromethanesulfonate, acetonitrile, propionitrile, acquivion ionomer, sodium butyrate, melamine, sebacic acid, 2,2-bipyridine, dodecanedioic acid, sodium trichloroacetate, dodecanoic acid, sodium dodecanoate, 15-crown-5, or trichloroacetic acid. In some embodiments, the additive enhances electrochemical properties. In other embodiments, the additive does not change the electrochemical properties.

[0368] In some embodiments, the electrolyte further includes a defoamer. For example, the electrolyte includes a polydimethylsiloxane trimethylsiloxy defoamer with a molecular weight (Mn) of about 1000amu to about 2000amu (e.g., about 1000amu to about 1500amu, or 1250amu). In some instances, the electrolyte includes a defoamer of about 0.1 wt % to about 0.35 wt % (e.g., a polydimethylsiloxane trimethylsiloxy defoamer with a molecular weight (Mn) of about 1000amu to about 2000amu (e.g., about 1000amu to about 1500amu, or 1250amu).

[0369] Another aspect of the present invention provides an electrolyte for use in a secondary zinc-halide electrochemical cell, comprising about 30 wt % to about 40 wt % ZnBr2, ZnCl2, or any combination thereof, about 4 wt % to about 12 wt % KBr, about 4 wt % to about 12 wt % KCl, about 0.5 wt % to about 10 wt % glyme, and about 1 wt % to about 5 wt % of one or more quaternary ammonium agents.

[0370] Another aspect of the present invention provides an electrolyte for use in a secondary zinc-halide electrochemical cell, comprising about 30 wt % to about 40 wt % ZnBr2, about 4 wt % to about 12 wt % KBr, about 4 wt % to about 12 wt % KCl, about 0.5 wt % to about 10 wt % glyme, and about 1 wt % to about 5 wt % of one or more quaternary ammonium agents.

[0371] Another aspect of the present invention provides an electrolyte for use in a secondary zinc-halide electrochemical cell, comprising about 30 wt % to about 40 wt % ZnBr2 and about 0.01 wt % to about 0.9 wt % of one or more additives selected from Sn, In, Ga, Al, Tl, Bi, Pb, Sb, Ag, Mn, Fe, or any combination thereof.

[0372] In some embodiments, the electrolyte comprises about 30 wt % to about 40 wt % ZnBr2, about 5 wt % to about 15 wt % KBr, about 5 wt % to about 15 wt % KCl, about 0.5 wt % to about 10 wt % of one or more quaternary ammonium agents, about 0.1 wt % to about 2 wt % acetic acid, and about 0.05 wt % to about 4 wt % crown ether.

[0373] In some embodiments, the electrolyte comprises about 30 wt % to about 40 wt % ZnBr2, about 5 wt % to about 15 wt % KBr, about 5 wt % to about 15 wt % KCl, about 0.5 wt % to about 10 wt % of one or more quaternary ammonium agents, about 0.1 wt % to about 2 wt % acetic acid, about 0.05 wt % to about 4 wt % crown ether, and wherein the one or more quaternary ammonium agents include tetraethylammonium bromide.

[0374] In some embodiments, the electrolyte comprises about 30 wt % to about 40 wt % ZnBr2, about 5 wt % to about 15 wt % KBr, about 5 wt % to about 15 wt % KCl, about 0.5 wt % to about 10 wt % of one or more quaternary ammonium agents, about 0.1 wt % to about 2 wt % acetic acid, about 0.05 wt % to about 4 wt % crown ether, and wherein the one or more quaternary ammonium agents include trimethylpropylammonium bromide.

[0375] In some embodiments, the electrolyte comprises about 30 wt % to about 40 wt % ZnBr2, about 5 wt % to about 15 wt % KBr, about 5 wt % to about 15 wt % KCl, about 0.5 wt % to about 10 wt % of one or more quaternary ammonium agents, about 0.1 wt % to about 2 wt % acetic acid, about 0.05 wt % to about 4 wt % crown ether, and wherein the one or more quaternary ammonium agents include tetraethylammonium bromide, methylethylpyridinium bromide, and hexadecyltrimethylammonium bromide. In another embodiment, the methylethylpyridinium bromide is selected from 1-ethyl-2-methylpyridinium bromide, 1-ethyl-3-methylpyridinium bromide, or 1-ethyl-4-methylpyridinium bromide. In another embodiment, the methylethylpyridinium bromide is 1-ethyl-3-methylpyridinium bromide.

[0376] In some embodiments, the electrolyte comprises about 30 wt % to about 40 wt % ZnBr2, about 5 wt % to about 15 wt % KBr, about 5 wt % to about 15 wt % KCl, about 0.5 wt % to about 10 wt % of one or more quaternary ammonium agents, about 0.1 wt % to about 2 wt % acetic acid, about 0.05 wt % to about 4 wt % crown ether, and wherein the one or more quaternary ammonium agents include triethylpropylammonium bromide, methylethylpyridinium bromide, and hexadecyltriethylammonium bromide. In another embodiment, the methylethylpyridinium bromide is 1-ethyl-2-methylpyridinium bromide.

[0377] In some embodiments, the electrolyte comprises about 30 wt % to about 40 wt % ZnBr2, about 5 wt % to about 15 wt % KBr, about 5 wt % to about 15 wt % KCl, about 0.5 wt % to about 10 wt % of one or more quaternary ammonium agents, about 0.1 wt % to about 2 wt % acetic acid, about 0.05 wt % to about 4 wt % crown ether, and wherein the one or more quaternary ammonium agents include triethylpropylammonium bromide, 1-butyl-3-methylpyridinium bromide, and hexadecyltriethylammonium bromide.

[0378] In some embodiments, the electrolyte comprises about 30 wt % to about 40 wt % ZnBr2, about 5 wt % to about 15 wt % KBr, about 5 wt % to about 15 wt % KCl, about 0.5 wt % to about 10 wt % of one or more quaternary ammonium agents, about 0.1 wt % to about 2 wt % acetic acid, about 0.05 wt % to about 4 wt % crown ether, and wherein the one or more quaternary ammonium agents include triethylpropylammonium bromide, 1-ethyl-3-methylpyridinium bromide, and hexadecyltriethylammonium bromide.

[0379] In some embodiments, the electrolyte comprises about 30 wt % to about 40 wt % ZnBr2, about 5 wt % to about 15 wt % KBr, about 5 wt % to about 15 wt % KCl, about 0.5 wt % to about 10 wt % of one or more quaternary ammonium agents, about 0.1 wt % to about 2 wt % acetic acid, about 0.05 wt % to about 4 wt % crown ether, and wherein the one or more quaternary ammonium agents include triethylpropylammonium bromide, 1-ethyl-2-methylpyridinium bromide, and hexadecyltriethylammonium bromide.

[0380] In some embodiments, the electrolyte comprises about 30 wt % to about 40 wt % ZnBr2, about 5 wt % to about 15 wt % KBr, about 5 wt % to about 15 wt % KCl, about 0.5 wt % to about 10 wt % of one or more quaternary ammonium agents, about 0.1 wt % to about 2 wt % acetic acid, about 0.05 wt % to about 4 wt % crown ether, and wherein the one or more quaternary ammonium agents include triethylpropylammonium bromide, 1-ethyl-4-methylpyridinium bromide, and hexadecyltriethylammonium bromide.

[0381] In some embodiments, the electrolyte comprises about 30 wt % to about 40 wt % ZnBr2, about 5 wt % to about 15 wt % KBr, about 5 wt % to about 15 wt % KCl, about 0.5 wt % to about 10 wt % of one or more quaternary ammonium agents, about 0.1 wt % to about 2 wt % acetic acid, about 0.05 wt % to about 4 wt % crown ether, and wherein the one or more quaternary ammonium agents include tetraethylammonium bromide, 1-butyl-3-methylpyridinium bromide, and hexadecyltriethylammonium bromide.

[0382] In some embodiments, the electrolyte comprises about 30 wt % to about 40 wt % ZnBr2, about 5 wt % to about 15 wt % KBr, about 5 wt % to about 15 wt % KCl, about 0.5 wt % to about 10 wt % of one or more quaternary ammonium agents, about 0.1 wt % to about 2 wt % acetic acid, about 0.05 wt % to about 4 wt % crown ether, and wherein the one or more quaternary ammonium agents include at least tetraethylammonium bromide, N-ethyl-N-methylmorpholinium bromide, and hexadecyltriethylammonium bromide.

[0383] In some embodiments, the electrolyte comprises about 30 wt % to about 40 wt % ZnBr2, about 5 wt % to about 15 wt % KBr, about 5 wt % to about 15 wt % KCl, about 0.5 wt % to about 10 wt % of one or more quaternary ammonium agents, about 0.1 wt % to about 2 wt % acetic acid, about 0.05 wt % to about 4 wt % crown ether, and wherein the one or more quaternary ammonium agents include trimethylpropylammonium bromide, 1-butyl-1-methylpyrrolidinium bromide, and hexadecyltriethylammonium bromide.

[0384] In some embodiments, the electrolyte comprises about 30 wt % to about 40 wt % ZnBr2, about 5 wt % to about 15 wt % KBr, about 5 wt % to about 15 wt % KCl, about 0.5 wt % to about 10 wt % of one or more quaternary ammonium agents, wherein the one or more quaternary ammonium agents include tetraethylammonium bromide, methylethylpyridinium bromide, and hexadecyltriethylammonium bromide.

[0385] In some embodiments, the electrolyte comprises about 30 wt % to about 40 wt % ZnBr2, about 5 wt % to about 15 wt % KBr, about 5 wt % to about 15 wt % KCl, about 0.5 wt % to about 10 wt % of one or more quaternary ammonium agents, wherein the one or more quaternary ammonium agents include trimethylpropylammonium bromide, 1-butyl-1-methylpyrrolidinium bromide, and hexadecyltriethylammonium bromide.

[0386] Method for preparing electrolyte

[0387] Another aspect of the present invention provides a method of preparing an electrolyte for use in a secondary zinc-halogen electrochemical cell, comprising mixing ZnBr2, KBr, KCl, water, and one or more quaternary ammonium agents to produce a mixture, wherein the mixture comprises about 30 wt % to about 40 wt % ZnBr2, about 4 wt % to about 12 wt % KBr, about 4 wt % to about 12 wt % KCl, about 0.5 wt % to about 10 wt % of one or more quaternary ammonium agents, and about 25 wt % to about 45 wt % water.

[0388] Alternatively, the mixture comprises about 30 wt % to about 40 wt % ZnBr2, about 8 wt % to about 12 wt % KBr, about 8 wt % to about 14 wt % KCl, about 0.5 wt % to about 10 wt % of one or more quaternary ammonium agents, and about 25 wt % to about 45 wt % water.

[0389] In some embodiments, the mixture comprises from about 32 wt % to about 36 wt % ZnBr2.

[0390] In some embodiments, the mixture comprises about 4 wt % to about 12 wt % (e.g., about 6 wt % to about 10 wt %) potassium bromide (KBr). In some embodiments, the mixture comprises about 8 wt % to about 12 wt % potassium bromide (KBr).

[0391] In some embodiments, the mixture comprises about 4 wt % to about 12 wt % (e.g., about 6 wt % to about 10 wt %) potassium chloride (KCl). In some embodiments, the mixture comprises about 8 wt % to about 14 wt % potassium chloride (KCl). In some embodiments, the mixture comprises about 11 wt % to about 14 wt % potassium chloride (KCl).

[0392] In some embodiments, the mixture comprises about 27 wt % to about 43 wt % (eg, about 30 wt % to about 40 wt % or about 35 wt % to about 41 wt %) water.

[0393] In some embodiments, one or more quaternary ammonium agents are salts having Formula I

[0394]

[0395] As described in this article.

[0396] In some embodiments, the one or more quaternary ammonium agents include a quaternary ammonium agent selected from the group consisting of ammonium halides (e.g., NH4Br, NH4Cl, or any combination thereof), tetraalkylammonium halides (e.g., tetramethylammonium bromide, tetramethylammonium chloride, tetraethylammonium bromide, tetraethylammonium chloride, combinations thereof, etc.), heterocyclic ammonium halides (e.g., N-methyl-N-ethylpyrrolidinium chloride, N-ethyl-N-methylpyrrolidinium halide, combinations thereof, etc.), or any combination thereof. In other embodiments, the one or more quaternary ammonium agents include a quaternary ammonium agent selected from the group consisting of ammonium chloride, tetraethylammonium bromide, trimethylpropylammonium bromide, N-methyl-N-ethylmorpholinium bromide, N-ethyl-N-methylmorpholinium bromide, N-methyl-N-butylmorpholinium bromide, N-methyl-N-ethylpyrrolidinium bromide, N,N,N-triethyl-N-propylammonium bromide, N-ethyl-N-propylpyrrolidinium bromide, N-propyl-N-butylpyrrolidinium bromide, N-methyl-N-butyl In some embodiments, the mixture comprises one or more quaternary ammonium agents in an amount of about 1% to about 5% by weight. In some embodiments, the one or more quaternary ammonium agents include N-methyl-N-ethylmorpholinium bromide, N-ethyl-N-pentylpyrrolidinium bromide, N-ethyl-N-pentylpyrrolidinium bromide, N-ethyl-N-butylpyrrolidinium bromide, trimethylene-bis(N-methylpyrrolidinium) dibromide, N-butyl-N-pentylpyrrolidinium bromide, N-methyl-N-propylpyrrolidinium bromide, N-propyl-N-pentylpyrrolidinium bromide, and any combination thereof. In some instances, the mixture comprises one or more quaternary ammonium agents in an amount of about 1% to about 5% by weight. Also, in some embodiments, the one or more quaternary ammonium agents include N-methyl-N-ethylmorpholinium bromide. In other examples, the mixture comprises about 0.25 wt % to about 1.25 wt % of N-methyl-N-ethylmorpholinium bromide. Also, in some examples, the one or more quaternary ammonium agents include tetraethylammonium bromide, trimethylpropylammonium bromide, or any combination thereof. For example, the electrolyte comprises about 1 wt % to about 5 wt % of tetraethylammonium bromide.

[0397] In some embodiments, the one or more quaternary ammonium agents include a quaternary ammonium agent selected from the group consisting of ammonium bromide complexes, imidazolium bromide complexes, pyrrolidinium bromide complexes, pyridinium bromide complexes, phosphonium bromide complexes, and morpholinium bromide complexes.

[0398] In some embodiments, the one or more quaternary ammonium agents include a quaternary ammonium agent selected from the group consisting of tetraethylammonium (TEA) bromide, N-ethyl-N-methylmorpholinium (MEM) bromide, trimethylpropylammonium bromide, 1-ethyl-3-methylimidazolium bromide, 1-butyl-3-methylimidazolium bromide, 1-butyl-1-methylpyrrolidinium bromide, 1-ethyl-2-methylpyridinium bromide, 1-ethyl-3-methylpyridinium bromide, 1-ethyl-2-methylpyridinium bromide, 1-ethyl-4-methylpyridinium bromide, 1-methyl-1-propylpiperidinium bromide, dodecyltrimethylammonium bromide, 1-ethyl-2,3-dimethylimidazolium bromide, 1-decyl-3-methylimidazolium bromide, 1-butyl-2,3-dimethylimidazolium bromide, 1-methyl-3-octylimidazolium bromide, 1-methyl-3-hexylimidazolium bromide, 1-butyl-3-methylpyridinium bromide, 1-butyl-4-methylpyridinium bromide, 1-hexylpyridinium bromide, tetraethylphosphonium bromide, 1-methyl-1-propylpyrrolidinium bromide, triethylmethylammonium chloride, hexyltrimethylammonium bromide, hexyltrimethylammonium chloride, and hexadecyltriethylammonium bromide. For example, one or more quaternary ammonium agents include 1-ethyl-3-methylpyridinium bromide, 1-ethyl-2-methylpyridinium bromide, 1-ethyl-4-methylpyridinium bromide, 1-butyl-3-methylpyridinium bromide or 1-butyl-1-methylpyrrolidinium bromide. For example, the electrolyte includes about 1 wt % to about 4 wt % (e.g., about 1.5 wt % to about 3 wt %) of 1-ethyl-3-methylpyridinium bromide, 1-ethyl-2-methylpyridinium bromide, 1-ethyl-4-methylpyridinium bromide, 1-butyl-3-methylpyridinium bromide or 1-butyl-1-methylpyrrolidinium bromide.

[0399] In some embodiments, the one or more quaternary ammonium agents include cetyltriethylammonium bromide (CTAB).For example, the electrolyte includes about 0.05 wt % to about 1 wt % (e.g., about 0.1 wt % to about 0.5 wt %) of cetyltriethylammonium bromide (CTAB).

[0400] In some instances, one or more quaternary ammonium agents include tetraethylammonium bromide, trimethylpropylammonium bromide, or any combination thereof. For example, the electrolyte comprises about 1 wt % to about 5 wt % (e.g., about 1.5 wt % to about 3.5 wt %) of tetraethylammonium bromide. For example, the electrolyte comprises about 1 wt % to about 5 wt % (e.g., about 1.5 wt % to about 3.5 wt %) of trimethylpropylammonium bromide.

[0401] Some embodiments additionally include mixing glyme with ZnBr and other ingredients (e.g., KBr, KCl, quaternary ammonium agent, and water), wherein the mixture comprises about 0.5 wt % to about 10 wt % (e.g., about 1 wt % to about 7.5 wt %) of glyme. In some instances, glyme comprises monoglyme, diglyme, triglyme, tetraglyme, or any combination thereof. For example, glyme comprises tetraglyme. In other instances, the mixture comprises about 1 wt % to about 5 wt % of tetraglyme.

[0402] Some embodiments further include mixing DME-PEG with ZnBr2 and other ingredients (e.g., KBr, KCl, quaternary ammonium agent, water and / or glyme) to produce a mixture, wherein the mixture comprises about 0.5 wt % to about 2.5 wt % (e.g., about 1 wt % to about 2.25 wt %) of MPEG. In some examples, the DME-PEG has an average molecular weight (e.g., number average molecular weight M) of about 350 amu to about 3000 amu. n In other examples, the DME-PEG has an average molecular weight (eg, number average molecular weight M) of about 1200 amu to about 3000 amu. n And, in some examples, the mixture further comprises about 5 wt % to about 10 wt % of DME-PEG, wherein the DME-PEG has an average molecular weight (e.g., number average molecular weight Mn) of about 1500 amu to about 2500 amu (e.g., about 2000 amu).

[0403] Some embodiments further include mixing the crown ether with ZnBr2 and other ingredients (e.g., KBr, KCl, quaternary ammonium agent, water, etc.) to generate a mixture, wherein the mixture comprises about 0.05 wt % to about 4 wt % of the crown ether. In some instances, the crown ether is 18-crown-6 or 15-crown-5. In some instances, the mixture comprises about 0.1 wt % to about 1 wt % of the crown ether.

[0404] Some embodiments further comprise mixing a substantially water-miscible alcohol with ZnBr2 and other ingredients (e.g., KBr, KCl, quaternary ammonium agent, water, glyme, and / or DME-PEG) to produce a mixture, wherein the mixture comprises about 0.1 wt % to about 1.0 wt % of the alcohol. For example, the alcohol comprises C 1-4 Alcohol. In other examples, the alcohol includes methanol, ethanol, 1-propanol, isopropanol, 1-butanol, sec-butanol, isobutanol, tert-butanol, or any combination thereof. And in some examples, the mixture further comprises about 0.25 wt % to about 0.75 wt % of tert-butanol.

[0405] Some embodiments further include mixing C1-10 The diol is mixed with ZnBr2 and other ingredients (e.g., KBr, KCl, quaternary ammonium agent, water, glyme, DME-PEG, and / or alcohol) to form a mixture, wherein the mixture contains about 0.25 wt % to about 5 wt % (e.g., about 0.5 wt % to about 4 wt %) of C 1-10 In some examples, the diol includes ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, hexylene glycol, or any combination thereof. Also, in some examples, the mixture includes about 0.25 wt % to about 2.5 wt % neopentyl glycol.

[0406] Some embodiments further comprise mixing one or more additives selected from Sn, In, Ga, Al, Tl, Bi, Pb, Sb, Ag, Mn, or Fe with ZnBr and other ingredients (e.g., KBr, KCl, quaternary ammonium agent, water, glyme, DME-PEG, alcohol, and / or C 1-10 The mixture comprises less than 1 wt % of one or more additives selected from Sn, In, Ga, Al, Tl, Bi, Pb, Sb, Ag, Mn or Fe. For example, the mixture comprises less than 1 wt % of Sn and In.

[0407] Some embodiments further comprise adding to the mixture a sufficient amount of HBr to impart to the mixture a pH of about 2 to about 4 (about 2.5 to about 3.5).

[0408] Some embodiments further include mixing acetic acid with ZnBr2 and other ingredients (e.g., KBr, KCl, quaternary ammonium agents, water, etc.) to produce a mixture, wherein the mixture comprises about 0.1 wt% to about 2 wt% (e.g., about 0.3 wt% to about 1 wt%) acetic acid.

[0409] Some embodiments further include mixing citric acid monohydrate with ZnBr2 and other ingredients (e.g., KBr, KCl, quaternary ammonium agent, water, etc.) to produce a mixture, wherein the mixture comprises about 2 wt % to about 8 wt % (e.g., about 3 wt % to about 5 wt %) of citric acid monohydrate.

[0410] Some embodiments further include mixing potassium dihydrogen citrate monohydrate with ZnBr2 and other ingredients (e.g., KBr, KCl, quaternary ammonium agent, water, etc.) to produce a mixture, wherein the mixture contains about 2 wt % to about 8 wt % (e.g., about 3 wt % to about 5 wt %) of potassium dihydrogen citrate monohydrate.

[0411] In some embodiments, ZnBr2, KBr, KCl, water, and one or more quaternary ammonium agents are mixed at a temperature of about 15°C to about 30°C (eg, room temperature).

[0412] In some embodiments, ZnBr2, KBr, KCl, water, and one or more quaternary ammonium agents are mixed under stirring (eg, the mixture is agitated).

[0413] In some embodiments, the mixtures described herein are optionally filtered. In some embodiments, the mixtures described herein are filtered. In some embodiments, the mixtures described herein are not filtered.

[0414] Another aspect of the present invention provides an electrolyte for use in a secondary zinc-bromine electrochemical cell, comprising from about 25 wt % to about 45 wt % ZnBr2, from about 25 wt % to about 45 wt % water, and from 1 wt % to about 25 wt % aggregated amount of one or more quaternary ammonium agents, wherein the one or more quaternary ammonium agents comprises at least triethylmethylammonium bromide.

[0415] In some embodiments, the electrolyte comprises about 30 wt % to about 40 wt % ZnBr 2. In other embodiments, the electrolyte comprises about 32 wt % to about 38 wt % ZnBr 2.

[0416] In some embodiments, the electrolyte comprises from about 1.5 wt % to about 7.5 wt % ZnCl 2 .

[0417] In some embodiments, the electrolyte comprises about 35 wt % to about 45 wt % water.

[0418] In some embodiments, the electrolyte comprises from about 1 wt % to about 5 wt % KBr. For example, the electrolyte comprises from about 1.5 wt % to about 4.5 wt % KBr.

[0419] In some embodiments, the electrolyte comprises about 5 wt % to about 15 wt % KCl.

[0420] In certain embodiments, electrolyte comprises the ether of about 0.5 % by weight to about 2.5 % by weight, is selected from the ether of DME-PEG, dimethyl ether or any combination thereof. In some instances, ether is DME-PEG, and DME-PEG has the mean molecular weight of about 350amu to about 3000amu. In other instances, DME-PEG has the mean molecular weight of about 750amu to about 2500amu. In certain embodiments, ether is DME-PEG, and electrolyte comprises the DME-PEG of about 0.1 % by weight to about 0.5 % by weight, and the DME-PEG has the DME-PEG of the mean molecular weight of about 750amu to about 1250amu. In other embodiments, ether is DME-PEG, and electrolyte comprises the DME-PEG of about 1.0 % by weight to about 2.0 % by weight, and the DME-PEG has the DME-PEG of the mean molecular weight of about 1750amu to about 2250amu. And, in some examples, the ether is DME-PEG, the electrolyte comprises about 0.1 wt % to about 0.5 wt % DME-PEG having an average molecular weight of about 750 amu to about 1250 amu, and the electrolyte further comprises about 1 wt % to about 2 wt % DME-PEG having an average molecular weight of about 1750 amu to about 2250 amu.

[0421] In some embodiments, the electrolyte further comprises about 1 wt % to about 10 wt % triethylmethylammonium bromide. For example, the electrolyte comprises about 1.5 wt % to about 7.5 wt % triethylammonium bromide.

[0422] In some embodiments, the one or more quaternary ammonium agents further include at least one quaternary ammonium agent selected from the group consisting of ammonium chloride, tetraethylammonium bromide, trimethylpropylammonium bromide, N-methyl-N-ethylmorpholinium bromide, N-methyl-N-ethylmorpholinium bromide (MEMBr), N-methyl-N-butylmorpholinium bromide, N-methyl-N-ethylpyrrolidinium bromide, N,N,N-triethyl-N-propylammonium bromide, N-ethyl-N-propylpyrrolidinium bromide, N-propyl-N-butylpyrrolidinium bromide, N-methyl-N-butylpyrrolidinium bromide, 1-methyl-1-butylpyrrolidinium bromide, N-ethyl

[0063] The following are some of the compounds described herein: trimethyl-N-(2-chlorovinyl)pyrrolidinium bromide, N-methyl-N-hexylpyrrolidinium bromide, N-methyl-N-pentylpyrrolidinium bromide, N-ethyl-N-pentylpyrrolidinium bromide, N-ethyl-N-butylpyrrolidinium bromide, trimethyl-di(N-methylpyrrolidinium) dibromide, N-butyl-N-pentylpyrrolidinium bromide, N-methyl-N-propylpyrrolidinium bromide, N-propyl-N-pentylpyrrolidinium bromide, 1-ethyl-4-methylpyridinium bromide, 1-ethyl-2-methylpyridinium bromide, 1-butyl-3-methylpyridinium bromide, and hexadecyltrimethylammonium bromide.

[0423] In an alternative embodiment, the one or more quaternary ammonium agents further include at least one quaternary ammonium agent selected from the group consisting of: 1-ethyl-4-methylpyridinium bromide, 1-ethyl-2-methylpyridinium bromide, and 1-butyl-3-methylpyridinium bromide. For example, the one or more quaternary ammonium agents further include 1-ethyl-2-methylpyridinium bromide, and the electrolyte further includes about 1.0 wt % to about 10 wt % of 1-ethyl-2-methylpyridinium bromide.

[0424] In some embodiments, the one or more quaternary ammonium agents additionally include cetyltrimethylammonium bromide, and the electrolyte further comprises from about 0.05 wt % to about 0.10 wt % cetyltrimethylammonium bromide.

[0425] In some embodiments, the electrolyte comprises an acid or a conjugate base of an acid selected from acetic acid, nitric acid and citric acid. For example, the electrolyte comprises about 0.1 wt % to about 1.0 wt % of glacial acetic acid. In other examples, the electrolyte comprises about 0.1 wt % to about 1.0 wt % of HBr. In other examples, the electrolyte comprises about 0.12 wt % to about 0.08 wt % of nitric acid. In some examples, the electrolyte comprises about 3.5 wt % to about 4.5 wt % of citric acid. And in some examples, the electrolyte comprises about 3.5 wt % to about 4.5 wt % of potassium dihydrogen citrate.

[0426] Another aspect of the present invention provides an electrolyte for use in a secondary zinc-halide electrochemical cell, comprising about 25 wt % to about 45 wt % ZnBr2, about 25 wt % to about 45 wt % water, about 1 wt % to about 5 wt % KBr, about 5 wt % to about 15 wt % KCl, and about 1 wt % to about 10 wt % triethylmethylammonium bromide.

[0427] In some embodiments, the electrolyte comprises from about 0.1 wt % to about 1.0 wt % glacial acetic acid.

[0428] In some embodiments, the electrolyte comprises about 0.1 wt % to about 0.5 wt % DME-PEG having an average molecular weight of about 750 amu to about 1250 amu.

[0429] In some embodiments, the electrolyte comprises about 1.0 wt % to about 2.0 wt % DME-PEG having an average molecular weight of about 1750 amu to about 2250 amu.

[0430] In some embodiments, the electrolyte comprises about 1.0 wt % to about 10 wt % of at least a quaternary ammonium agent selected from the group consisting of 1-ethyl-4-methylpyridinium bromide, 1-ethyl-2-methylpyridinium ammonium bromide, and 1-butyl-3-methylpyridinium bromide.

[0431] In some embodiments, the electrolyte includes about 0.05 wt % to about 0.10 wt % cetyltrimethylammonium bromide.

[0432] Another aspect of the present invention provides a method of preparing an electrolyte for use in a secondary zinc-halogen electrochemical cell, comprising mixing ZnBr2, KBr, KCl and triethylmethylammonium bromide under aqueous conditions to produce a mixture and stirring the mixture until solids have dissolved, wherein the mixture comprises about 25 wt % to about 45 wt % ZnBr2, about 25 wt % to about 45 wt % water, about 1 wt % to about 5 wt % KBr, about 5 wt % to about 15 wt % KCl, and about 1 wt % to about 10 wt % triethylmethylammonium bromide.

[0433] B.Battery pack

[0434] refer to Figures 18 to 20 Another aspect of the present invention provides a battery pack including a plurality of bipolar electrodes at least partially disposed in a zinc-halogen electrolyte and between a cathode terminal assembly and an anode terminal assembly. The cathode terminal assembly, the anode terminal assembly, the zinc-halogen electrolyte, and the bipolar electrodes include any embodiment described herein.

[0435] 1. Frame components

[0436] In some embodiments, the battery or electrochemical cell of the present invention includes a frame member 114 between two adjacent bipolar electrodes or between a bipolar electrode and a terminal assembly (eg, a terminal anode assembly or a terminal cathode assembly).

[0437] exist Fig.23 In one embodiment shown, the frame member has an outer peripheral edge 604 and an inner peripheral edge 608 defining an open interior area 606. The inner peripheral edge 608 defines the open interior area so that the cathode assembly of the bipolar electrode is adjacent to the inner surface of the terminal end plate or the rear surface of the adjacent bipolar electrode plate without being interfered or obstructed by the frame member. Thus, the open interior area is at least as large as the electrochemically active area of ​​the terminal end plate and at least as large as the reduced surface of the pocket portion of the cathode holder of the cathode assembly. In some embodiments, the frame member is configured so that the open interior area is approximately centered around the center of the electrochemically active area of ​​the terminal end plate received by the frame member and / or the center of the cathode assembly disposed on the bipolar electrode plate of the bipolar electrode. In some embodiments, the outer periphery of the frame member defines the outer surface of the battery pack or electrochemical cell.

[0438] In some embodiments, the frame member includes a first side 614 that is opposite to and fixed to the first bipolar electrode plate or the terminal end plate, and a second side 616 that is disposed on an opposite side of the frame member that is different from the first side, and the second side 616 is opposite to and fixed to the second bipolar electrode plate. The first and second electrode plates and the terminal end plate can be configured to have substantially the same size and shape.

[0439] In some embodiments, each side of the frame member includes a sealing groove 612 extending around the inner peripheral edge. In some examples, the size and shape of each sealing groove is designed to conform to the contour of the peripheral edge of the corresponding bipolar electrode plate or terminal end plate fixed by the frame member. And, in some embodiments, each sealing groove is configured to receive a seal 116 ( Fig.21 ) (e.g., O-ring or gasket 404; Fig.21 Also shown are the sealing sides 406 and bottom 408 of the seal, which forms a substantially leak-free seal when the seal is compressed between the corresponding electrode plate or end plate and the frame member when the electrochemical cell or battery is assembled, thereby providing a sealed interface between the electrode plate or end plate and the frame member. The seal cooperates to secure the electrolyte between the opposing electrode plates and the frame member or between the electrode plates, end plates and the frame.

[0440] In some embodiments, the frame member has one or more fixed fences 610 that protrude into the open interior region and limit the movement of the pressure plate 105 or electrode plate when assembling the battery. In other embodiments, the one or more fixed fences may extend from the inner peripheral edge into the interior region. In some instances, the fixed fences are operable to contact a generally flat surface of the cathode holder (e.g., a pocket portion of the cathode holder) that protrudes away from the front surface of the electrode plate in a direction toward the frame member. The fixed fences can reduce or prevent the cathode holder from bending and deforming from being flat during charging of the battery module. The fixed fences may include openings or cutouts to reduce the overall weight of the frame structure.

[0441] Each frame member can be formed of flame retardant polypropylene fiber, polypropylene filled with glass fiber, flame retardant high-density polyethylene (e.g., filled with glass fiber or unfilled), or polyvinyl fluoride. Each frame member can receive two adjacent electrode plates or electrode plates and terminal end plates. Furthermore, one of the electrode plates can include a surface bonded to a cathode assembly having a carbon material and a separator arranged in a layered structure and a cathode holder surrounding the carbon material and the separator. Each frame can also accommodate an aqueous electrolyte solution (e.g., a zinc-halogen electrolyte or a zinc-bromine electrolyte). As Fig.19 As shown, the frame member disposed adjacent to the pressure plate may optionally include one or more pressure relief valves 402 or bursting discs to release excess pressure within the electrochemical cell or battery pack. In some embodiments, the pressure relief valve comprises a molded bracket configured to extend through the frame and a pressure relief umbrella or bursting disc (e.g., a bursting disc that ruptures at a pressure of about 300 psi or greater).

[0442] 2. Press plate

[0443] In some embodiments, the electrochemical cell or battery pack includes a pair of pressure plates 105, 105a, 105b located at the ends of the electrochemical cell or battery pack. In some embodiments, each pressure plate includes an outer surface 512 and an inner surface 504 disposed on opposite sides of the pressure plate, different from the outer surface and opposite to the adjacent frame member. Fig. 22 The outer surface of the press plate associated with the positive (+) anode terminal of the electrochemical cell or battery and the inner surface of the press plate associated with the negative (-) cathode of the electrochemical cell or battery are shown. In some embodiments, the press plate is formed of 6061-T6 aluminum and can be manufactured by stamping. In other embodiments, the press plate is formed of stainless steel and can be manufactured by machining. And, in some embodiments, the press plate is formed of ground steel.

[0444] In some embodiments, the terminal holes 502a, 502b extend through each press plate to expose the corresponding terminals for electrical connection with the connection / power cable. In some embodiments, the press plate has a through hole 602 (such as Fig.23 ), which are operable to receive one or more frame bolts or tie rods 120. For example, a first row of four (4) through holes may be spaced apart (e.g., evenly spaced apart) along a top edge of each platen, and a second row of four (4) through holes may be spaced apart (e.g., evenly spaced apart) along a bottom edge of each platen.

[0445] The outer surface of each press plate may include a cutout 508 to reduce the weight of the press plate and define a reinforcement member that reduces stress concentration when the press plate contacts an adjacent terminal frame member. In addition, the cutout can dissipate heat generated by the electrochemical cell or battery pack. The outer surface and the cutout can define one or more channels 510, which are operable to receive and route connection / power cables electrically connected to the exposed terminals and / or wiring harnesses for assembled battery modules. And, in some embodiments, each inner surface of the press plate has one or more cutouts 206.

[0446] In some embodiments, the interior surface of each press plate may include a generally flat surface operable to engage an outer surface of an adjacent frame member. In some embodiments, the interior surface of each press plate further defines a recessed area having a size and shape configured to receive at least a portion of a conductive cup-shaped member that engages and protrudes from a terminal end plate associated with a corresponding adjacent press plate. In some embodiments, an aperture may extend through the interior and exterior surfaces of the press plate end plates in lieu of the recessed area to expose at least a portion of the conductive cup-shaped member and the terminal.

[0447] In some embodiments of the electrochemical cell or battery pack of the present invention, each frame member and each pair of pressure plates have corresponding through holes that are configured to receive bolts or tie rods therethrough and serve to compress these components using fasteners 109 (e.g., nuts 108 and / or washers 106, 110) to assemble a substantially sealed electrochemical cell or battery pack.

[0448] In some embodiments, each frame member, each pressure plate, each terminal end plate, and each bipolar electrode plate has one or more corresponding through holes that serve as alignment features so that the terminals, conductive cup-shaped members, cathode assemblies, and electrochemically active areas share the same approximate center when the locating pin 112 is placed therein.

[0449] In some embodiments, the battery pack includes a first bipolar electrode, a second bipolar electrode, and a frame member 114, wherein the frame member is interposed between the first bipolar electrodes, the frame member has a first side and a second side, the first bipolar electrode has a first electrode plate, and the second bipolar electrode has a second electrode plate; and wherein the first side of the frame member is configured to receive at least a portion of a front side of the first electrode plate, and the second side of the frame member is configured to receive at least a portion of a rear side of the second electrode plate.

[0450] refer to Fig.19 and 20 Another aspect of the present invention provides a bipolar battery pack defining a longitudinal axis L, wherein the bipolar battery 1000 includes a pair of terminal assemblies 104 at the corresponding proximal end 101 and distal end 103 of the battery, each terminal assembly including a conductive cup-shaped member 310, which includes a terminal wall 312, a side wall 304, and an edge 306 separated from the terminal wall by the side wall; and a terminal end plate 302, which has an outer surface 316 and an inner surface 318 coplanar with the terminal wall and engages the corresponding edge at the outward surface, and when the corresponding terminal wall is in electrical contact with the corresponding terminal, the engagement enables bidirectional uniform current flow between the corresponding terminal 308 and the end plate through the cup-shaped member. In some embodiments, the terminal assembly corresponds to the above reference Figures 12 to 17 The terminal assembly 104. In some embodiments, the battery pack 1000 further includes at least one pair of intermediate bipolar electrodes 102, 102' arranged in a parallel orientation between a pair of terminal assemblies. In these embodiments, the intermediate cells include bipolar electrodes for distributing current between the terminal assemblies. Each intermediate cell includes a frame member 114 that accommodates components of the battery.

[0451] Fig. 20 Provided Fig.19Exploded view of a battery pack. In some embodiments, each battery pack or electrochemical cell further includes a corresponding press plate 105a, 105b, which is opposite to the outer surface of the end plate 302 and releasably fastened to contact the outer surface of the end plate 302, and each press plate includes an aperture 502a, 502b configured to receive a corresponding terminal 308. In some of these embodiments, at least a portion of the terminal wall of the conductive cup-shaped member is exposed through the aperture of the press plate. In other embodiments, at least a portion of the terminal wall and the side wall is exposed through the aperture of the press plate. FIG. 7 shows a press plate having its corresponding aperture formed therethrough. In other embodiments, a recessed area may be provided at the inward surface of each press plate, which is configured to receive a corresponding cup-shaped member. In these embodiments, a terminal hole may be formed through the recessed area of ​​each press plate to expose the terminal. In some embodiments, the outward / exterior surface of the press plate includes a cutout to reduce the total weight of the press plate and to help dissipate the heat generated by the battery.

[0452] In some embodiments, the pressure plate includes an opening operable to receive a tie rod and / or bolt secured by a fastener to compress the two pressure plates and bring the frame members together along the longitudinal axis L( Fig.19 ) between.

[0453] In some embodiments, the electrochemically active area of ​​each corresponding terminal end plate includes a first surface area surrounded by the corresponding edge and a remaining second surface area outside an outer perimeter of the corresponding edge, the first and second surface areas being substantially equal.

[0454] In some embodiments, each terminal wall protrudes away from the outward surface of the corresponding end plate.

[0455] In some embodiments, one of the terminal walls projects away from the outward surface of the corresponding end plate in a proximal direction along the longitudinal axis, and the other terminal wall projects away from the outward surface of the corresponding end plate in an opposite distal direction along the longitudinal axis.

[0456] In some embodiments, the terminal wall of the conductive cup-shaped member is exposed at a corresponding one of the proximal end and the distal end of the electrochemical cell assembly.

[0457] In some embodiments, one of the terminal assemblies in the battery pack or electrochemical cell further includes a cathode assembly 202, which is disposed on the inner surface of the corresponding end plate on the side opposite to the corresponding conductive cup-shaped member, and the cathode assembly is interposed between the inner surface of the end plate and the rear surface of the adjacent bipolar electrode plate.

[0458] In some embodiments, each edge is centered within the electrochemically active region of a corresponding end plate.

[0459] In some embodiments, each edge of the conductive cup-shaped member is joined to the outwardly facing surface of the corresponding end plate by welding or adhesive. In some examples, the adhesive is conductive.

[0460] In some embodiments, at least one of the conductive cup-shaped member or the terminal end plate comprises a copper / titanium cladding.

[0461] In some embodiments, the interior surface of at least one of the conductive cup-shaped members comprises copper. In other embodiments, the exterior surface of at least one of the conductive cup-shaped members comprises titanium.

[0462] In some embodiments, each corresponding terminal contacts a center position of a corresponding terminal wall.

[0463] In some embodiments, the edge includes a flange extending radially outward from the sidewall.

[0464] IV. Examples

[0465] Example 1A - Electrolyte Formulation

[0466] The ingredients used in the electrolyte formulations described below were of reagent grade.

[0467] Table 1: Ingredients used for electrolyte composition

[0468]

[0469]

[0470] The electrolyte of the present invention is prepared as follows:

[0471] Table 2: Electrolyte formulation No. 1-1 (basic formulation).

[0472] Element Amount (g) weight% <![CDATA[ZnBr2]]> 85 36.31 water 95 40.58 KBr 21 8.97 KCl 20 8.54 Acetic acid 1.11 0.47 1-Ethyl-2-methylpyridinium bromide 4.96 2.12 Tetraethylammonium bromide 6.1 2.61 18-Crown-6 0.55 0.23 Hexadecyltrimethylammonium bromide 0.4 0.17 total: 234.12 100.00

[0473] Electrolyte No. 1-1 produced a turbid mixture which was not filtered.

[0474] Electrolytes No. 1-2 were prepared using the same ingredients in the same amounts, but the electrolytes were filtered prior to testing.

[0475] Table 3: Electrolyte formulations No. 1-3.

[0476] Element Amount (g) weight% <![CDATA[ZnBr2]]> 85 34.82 water 95 38.92 KBr 21 8.60 KCl 20 8.19 Acetic acid 1.11 0.45 1-Ethyl-2-methylpyridinium bromide 4.96 2.03 Tetraethylammonium bromide 6.1 2.50 18-Crown-6 0.55 0.23 Hexadecyltrimethylammonium bromide 0.4 0.16 Citric Acid 10 4.10 total: 244.12 100.00

[0477] Table 4: Electrolyte formulations No. 1-4.

[0478]

[0479]

[0480] Test electrolyte formulation No. 3 was prepared as a filtered and unfiltered mixture.

[0481] Table 5: Electrolyte formulations No. 1-5.

[0482] Element Amount (g) weight% <![CDATA[ZnBr2]]> 101.3 36.78 water 100 36.31 KBr 23.8 8.64 KCl 37.2 13.51 Acetic acid 1.11 0.40 1-Ethyl-2-methylpyridinium bromide 4.96 1.80 Tetraethylammonium bromide 6.1 2.21 18-Crown-6 0.55 0.20 Hexadecyltrimethylammonium bromide 0.4 0.15 total: 275.42 100

[0483] Table 6: Electrolyte formulations No. 1-6.

[0484] Element Amount (g) weight% <![CDATA[ZnBr2]]> 85 36.31 water 95 40.58 KBr 21 8.97 KCl 20 8.54 Acetic acid 1.11 0.47 1-Butyl-1-methylpyridinium bromide 4.96 2.12 Trimethylpropylammonium bromide 6.1 2.61 18-Crown-6 0.55 0.23 Hexadecyltrimethylammonium bromide 0.4 0.17 total: 234.12 100.00

[0485] Table 7: Electrolyte formulations No. 1-7.

[0486] Element Amount (g) weight% <![CDATA[ZnBr2]]> 85 34.88 water 95 38.98 KBr 21 8.62 KCl 20 8.21 Acetic acid 1.11 0.46 1-Butyl-1-methylpyridinium bromide 4.96 2.04 Trimethylpropylammonium bromide 6.1 2.50 18-Crown-6 0.55 0.23 Potassium dihydrogen citrate 10 4.10 total: 243.72 100.00

[0487] Table 8: Electrolyte formulations No. 1-8.

[0488] Element Amount (g) weight% <![CDATA[ZnBr2]]> 85 36.37 water 95 40.65 KBr 21 8.99 KCl 20 8.56 Acetic acid 1.11 0.47 1-Ethyl-2-methylpyridinium bromide 4.96 2.12 Tetraethylammonium bromide 6.1 2.61 18-Crown-6 0.55 0.24 total: 234.12 100.00

[0489] Table 9: Electrolyte formulations No. 1-9.

[0490] Element Amount (g) weight% <![CDATA[ZnBr2]]> 85 36.25 water 95 40.52 KBr 21 8.96 KCl 20 8.53 Acetic acid 1.11 0.47 1-Ethyl-2-methylpyridinium bromide 4.96 2.12 Tetraethylammonium bromide 6.1 2.60 18-Crown-6 1.1 0.47 Hexadecyltrimethylammonium bromide 0.2 0.09 total: 234.47 100.00

[0491] Table 10: Electrolyte formulations No. 1-10.

[0492] Element Amount (g) weight% <![CDATA[ZnBr2]]> 85 34.70 water 95 38.78 KBr 21 8.57 KCl 20 8.16 Acetic acid 1.11 0.45 1-Ethyl-2-methylpyridinium bromide 9.92 4.05 Tetraethylammonium bromide 12.2 4.98 18-Crown-6 0.55 0.22 Hexadecyltrimethylammonium bromide 0.2 0.08 total: 244.98 100.00

[0493] Table 11: Electrolyte formulations No. 1-11.

[0494]

[0495]

[0496] Table 12: Electrolyte formulations No. 1-12.

[0497] Element Amount (g) weight% <![CDATA[ZnBr2]]> 85 36.34 water 95 40.61 KBr 21 8.98 KCl 20 8.55 Acetic acid 1.11 0.47 1-Butyl-3-methylpyridinium bromide 4.96 2.12 Tetraethylammonium bromide 6.1 2.61 18-Crown-6 0.55 0.24 Hexadecyltrimethylammonium bromide 0.2 0.09 total: 233.92 100.00

[0498] Table 13: Electrolyte formulations No. 1-13.

[0499] Element Amount (g) weight% <![CDATA[ZnBr2]]> 85 36.34 water 95 40.61 KBr 21 8.98 KCl 20 8.55 Acetic acid 1.11 0.47 N-Ethyl-N-methylmorpholinium bromide 4.96 2.12 Tetraethylammonium bromide 6.1 2.61 18-Crown-6 0.55 0.24 Hexadecyltrimethylammonium bromide 0.2 0.09 total: 233.92 100.00

[0500] Table 14: Electrolyte formulations No. 1-14.

[0501]

[0502]

[0503] Table 15: Electrolyte formulations No. 1-15.

[0504] Element Amount (g) weight% <![CDATA[ZnBr2]]> 85 35.29 water 95 39.44 KBr 21 8.72 KCl 20 8.30 Acetic acid 1.11 0.46 1-Butyl-3-methylpyridinium bromide 4.96 2.06 Trimethylpropylammonium bromide 6.1 2.53 18-Crown-6 1.1 0.46 Hexadecyltrimethylammonium bromide 0.2 0.08 Tetraethylammonium bromide 6.1 2.53 15-Crown-5 0.29 0.12 total: 240.86 100.00

[0505] Table 16: Electrolyte formulations No. 1-16.

[0506] Element Amount (g) weight% <![CDATA[ZnBr2]]> 85 34.69 water 95 38.77 KBr 21 8.57 KCl 20 8.16 Acetic acid 1.11 0.45 1-Ethyl-2-methylpyridinium bromide 9.92 4.05 Tetraethylammonium bromide 12.2 4.98 18-Crown-6 0.55 0.22 Hexadecyltrimethylammonium bromide 0.2 0.08 <![CDATA[SnCl2·2H2O]]> About 0.0047 About 0.0019 In(In in nitric acid solution) About 0.0025 About 0.0010 Nitric acid (from solution) About 0.026 About 0.0106 total: About 240.86 Approx. 100.00

[0507] Table 17: Electrolyte formulations No. 1-17.

[0508]

[0509]

[0510] Table 18: Electrolyte formulations No. 1-18.

[0511] Element Amount (g) weight% <![CDATA[ZnBr2]]> 85 34.00 water 95 38.00 KBr 21 8.40 KCl 20 8.00 Acetic acid 1.11 0.44 1-Ethyl-2-methylpyridinium bromide 9.92 3.97 Tetraethylammonium bromide 12.2 4.88 18-Crown-6 0.55 0.22 DME-PEG 2000 4 1.60 DME-PEG 1000 1 0.40 Hexadecyltrimethylammonium bromide 0.2 0.08 <![CDATA[SnCl2·2H2O]]> About 0.0047 About 0.0019 In(In in nitric acid solution) About 0.0025 About 0.0010 Nitric acid (from solution) About 0.026 About 0.0104 total: About 250.01 Approx. 100.00

[0512] Table 19: Electrolyte formulations No. 1-19.

[0513]

[0514]

[0515] Table 20: Electrolyte formulations No. 1-20.

[0516] Element Amount (g) weight% <![CDATA[ZnBr2]]> 77.3 32.33 water 95 39.73 <![CDATA[ZnCl2]]> 4.68 1.96 KCl 33.2 13.89 Acetic acid 1.11 0.46 1-Ethyl-2-methylpyridinium bromide 9.92 4.15 Tetraethylammonium bromide 12.2 5.10 18-Crown-6 0.55 0.23 DME-PEG 2000 4 1.67 DME-PEG 1000 1 0.42 Hexadecyltrimethylammonium bromide 0.1 0.04 <![CDATA[SnCl2·2H2O]]> About 0.0047 About 0.0020 In(In in nitric acid solution) About 0.0025 About 0.0010 Nitric acid (from solution) About 0.026 About 0.0109 total: About 239.09 Approx. 100.00

[0517] Table 21: Electrolyte formulations No. 1-21.

[0518] Element Amount (g) weight% <![CDATA[ZnBr2]]> 67.5 28.70 water 95 40.39 <![CDATA[ZnCl2]]> 10.6 4.51 KCl 33.2 14.12 Acetic acid 1.11 0.47 1-Ethyl-2-methylpyridinium bromide 9.92 4.22 Tetraethylammonium bromide 12.2 5.19 18-Crown-6 0.55 0.23 DME-PEG 2000 4 1.70 DME-PEG 1000 1 0.43 Hexadecyltrimethylammonium bromide 0.1 0.04 <![CDATA[SnCl2·2H2O]]> About 0.0047 About 0.0020 In(In in nitric acid solution) About 0.0025 About 0.0011 Nitric acid (from solution) About 0.026 About 0.0111 total: About 235.21 Approx. 100.00

[0519] Table 22: Electrolyte formulations No. 1-22.

[0520] Element Amount (g) weight% <![CDATA[ZnBr2]]> 85 30.83 water 95 34.46 KBr 21 7.62 KCl 45.8 16.61 Acetic acid 1.11 0.40 1-Ethyl-2-methylpyridinium bromide 9.92 3.60 Tetraethylammonium bromide 12.2 4.42 18-Crown-6 0.55 0.20 DME-PEG 2000 4 1.45 DME-PEG 1000 1 0.36 Hexadecyltrimethylammonium bromide 0.1 0.04 <![CDATA[SnCl2·2H2O]]> About 0.0047 About 0.0017 In(In in nitric acid solution) About 0.0025 About 0.0009 Nitric acid (from solution) About 0.026 About 0.0094 total: About 275.71 Approx. 100.00

[0521] Table 23: Electrolyte formulations No. 1-23.

[0522] Element Amount (g) weight% <![CDATA[ZnBr2]]> 85 32.92 water 95 36.80 KBr 21 8.13 KCl 20 7.75 Acetic acid 1.11 0.43 1-Ethyl-2-methylpyridinium bromide 14.88 5.77 Tetraethylammonium bromide 18.3 7.09 18-Crown-6 2.75 1.07 Hexadecyltrimethylammonium bromide 0.1 0.04 <![CDATA[SnCl2·2H2O]]> About 0.0047 About 0.0018 In(In in nitric acid solution) About 0.0025 About 0.0010 Nitric acid (from solution) About 0.026 About 0.0101 total: About 258.17 Approx. 100.00

[0523] Table 24: Electrolyte formulations No. 1-24.

[0524]

[0525]

[0526] Table 25: Electrolyte formulations No. 1-25.

[0527] Element Amount (g) weight% <![CDATA[ZnBr2]]> 85 34.40 water 95 38.44 KBr 21 8.50 KCl 20 8.09 Acetic acid 1.11 0.45 1-Ethyl-2-methylpyridinium bromide 7.92 3.21 Tetraethylammonium bromide 14.2 5.75 18-Crown-6 2.75 1.11 Hexadecyltrimethylammonium bromide 0.1 0.04 <![CDATA[SnCl2·2H2O]]> About 0.0047 About 0.0019 In(In in nitric acid solution) About 0.0025 About 0.0010 Nitric acid (from solution) About 0.026 About 0.0105 total: About 247.11 Approx. 100.00

[0528] Table 26: Electrolyte formulations No. 1-26.

[0529] Element Amount (g) weight% <![CDATA[ZnBr2]]> 85 34.40 water 95 38.44 KBr 21 8.50 KCl 20 8.09 Acetic acid 1.11 0.45 1-Ethyl-2-methylpyridinium bromide 9.92 4.01 Tetraethylammonium bromide 12.2 4.94 18-Crown-6 2.75 1.11 Hexadecyltrimethylammonium bromide 0.1 0.04 <![CDATA[SnCl2·2H2O]]> About 0.0047 About 0.0019 In(In in nitric acid solution) About 0.0025 About 0.0010 Nitric acid (from solution) About 0.026 About 0.0105 total: About 247.11 Approx. 100.00

[0530] Table 27: Electrolyte formulations No. 1-27.

[0531]

[0532]

[0533] Table 28: Electrolyte formulations No. 1-28.

[0534] Element Amount (g) weight% <![CDATA[ZnBr2]]> 85 36.37 water 95 40.65 KBr 21 8.99 KCl 20 8.56 Acetic acid 1.11 0.47 1-Ethyl-2-methylpyridinium bromide 9.92 4.24 Tetraethylphosphonium bromide 1 0.43 18-Crown-6 0.55 0.24 Hexadecyltrimethylammonium bromide 0.1 0.04 <![CDATA[SnCl2·2H2O]]> About 0.0047 About 0.0020 In(In in nitric acid solution) About 0.0025 About 0.0011 Nitric acid (from solution) About 0.026 About 0.0111 total: About 233.71 Approx. 100.00

[0535] Table 29: Electrolyte formulations No. 1-29.

[0536] Element Amount (g) weight% <![CDATA[ZnBr2]]> 85 34.79 water 95 38.89 KBr 21 8.60 KCl 20 8.19 Propionic acid 0.5 0.20 1-Ethyl-2-methylpyridinium bromide 9.92 4.06 Tetraethylphosphonium bromide 12.2 4.99 18-Crown-6 0.55 0.23 Hexadecyltrimethylammonium bromide 0.1 0.04 <![CDATA[SnCl2·2H2O]]> About 0.0047 About 0.0019 In(In in nitric acid solution) About 0.0025 About 0.0010 Nitric acid (from solution) About 0.026 About 0.0106 total: About 244.30 Approx. 100.00

[0537] Table 30: Electrolyte formulations No. 1-30.

[0538] Element Amount (g) weight% <![CDATA[ZnBr2]]> 85 34.68 water 95 38.76 KBr 21 8.57 KCl 20 8.16 Zinc acetate 1.32 0.54 1-Ethyl-2-methylpyridinium bromide 9.92 4.05 Tetraethylphosphonium bromide 12.2 4.98 18-Crown-6 0.55 0.22 Hexadecyltrimethylammonium bromide 0.1 0.04 <![CDATA[SnCl2·2H2O]]> About 0.0047 About 0.0019 In(In in nitric acid solution) About 0.0025 About 0.0010 Nitric acid (from solution) About 0.026 About 0.0106 total: About 245.12 Approx. 100.00

[0539] Table 31: Electrolyte formulations No. 1-31.

[0540] Element Amount (g) weight% <![CDATA[ZnBr2]]> 85 34.71 water 95 38.79 KBr 21 8.57 KCl 20 8.17 Acetic acid 1.11 0.45 1-Ethyl-4-methylpyridinium bromide 9.92 4.05 Tetraethylphosphonium bromide 12.2 4.98 18-Crown-6 0.55 0.22 Hexadecyltrimethylammonium bromide 0.1 0.04 <![CDATA[SnCl2·2H2O]]> About 0.0047 About 0.0019 In(In in nitric acid solution) About 0.0025 About 0.0010 Nitric acid (from solution) About 0.026 About 0.0106 total: About 244.91 Approx. 100.00

[0541] Table 32: Electrolyte formulations No. 1-32.

[0542]

[0543]

[0544] Table 33: Electrolyte formulations No. 1-33.

[0545] Element Amount (g) weight% <![CDATA[ZnBr2]]> 85 34.89 water 95 39.00 KBr 5.3 2.18 KCl 29.8 12.23 HBr 1.17 0.48 1-Ethyl-2-methylpyridinium bromide 9.92 4.07 Triethylmethylammonium bromide 12.2 5.01 Hexadecyltrimethylammonium bromide 0.2 0.08 mPEG-2K 4 1.64 mPEG-1K 1 0.41 total: About 243.59 Approx. 100.00

[0546] Table 34: Electrolyte formulations No. 1-34.

[0547] Element weight% <![CDATA[ZnBr2]]> 34.90 water 39.00 KBr 12.23 KCl 2.18 1-Ethyl-4-methylpyridinium bromide 4.07 Acetic acid 0.48 Triethylmethylammonium chloride 5.01 mPEG-2K 1.64 mPEG-1K 0.41 1,1-Dioctadecyl-4,4'-bipyridinium dibromide 0.11 Hexadecyltrimethylammonium bromide 0.08 total: Approx. 100.00

[0548] Table 35: Electrolyte formulations No. 1-35.

[0549]

[0550]

[0551] In Example 1, electrolytes containing various quaternary ammonium agents of the present invention were tested to evaluate the effects of the quaternary ammonium agents on the power and stability of zinc-bromine electrochemical cells. Fig.32Typical ranges of power and stability observed for most of the quaternary ammonium agents tested are shown and the quaternary ammonium agents are classified as ammonium complexing agents, pyridinium or pyrrolidinium complexing agents, or imidazolium complexing agents. Stable electrolytes, i.e., electrolytes that exhibit little change in pH after exposure to Br2 for 7 days at 60°C are desirable. Electrolytes with faster Br2 kinetics, i.e., electrolytes with greater maximum power at the Tafel limiting current for Br reduction, can enable cells with higher power and are also desirable.

[0552] pH stability test

[0553] In Example 1, stability experiments were performed on each of the above electrolytes to determine whether the ingredients in the electrolyte formulation were stable or exhibited significant changes in pH when exposed to Br2 at 60°C for 7 days.

[0554] In the above formulations, ZnBr2, deionized water (di water), KBr and KCl were added to a 500 mL flask and stirred until all the salts were dissolved (about 30 minutes). Acetic acid was then added, followed by stirring for about 5 minutes, followed by the addition of crown ether (when present), DME-PEG (when present) and any other organic components. The quaternary ammonium agent was then added, followed by mixing tin chloride dihydrate (when present) and indium-nitric acid solution (when present) into the formulation. Finally, concentrated HBr acid was added to each of the above formulations to adjust the pH to about 3.

[0555] Place 200 grams of electrolyte in an amber bottle. The amber bottle is used to protect the light-sensitive bromine from light. Measure the pH of the electrolyte. Add 3.75 grams of bromine to the electrolyte, cap the amber bottle tightly, and carefully shake the resulting mixture for at least 20 seconds.

[0556] The pH of the bromine-doped electrolyte is then taken after shaking the bottle. Next, a piece of paraffin film is wrapped around the top / lid of the amber bottle to make it airtight after the lid is closed, and the spiked electrolyte is placed in a furnace at 60°C for 7 days. After a period of 7 days, the pH of the spiked electrolyte is measured (after cooling to room temperature) to evaluate the effect of bromine on the composition of the electrolyte. After measuring and recording the pH of the solution for up to a week, it needs to be re-capped and re-wrapped with paraffin film and must be placed in the furnace again. If the electrolyte formulation does not change by more than a value of about 1.0 after being spiked with bromine and subjected to elevated temperatures for a period of 7 days, the electrolyte formulation is characterized as stable.

[0557] Power experiment

[0558] Each of the bromine-doped electrolytes was added to a three-necked round bottom flask. A glassy carbon working electrode was added to the first neck of the flask, a zinc metal counter electrode was added to the second neck of the flask, and a saturated mercurous chloride reference electrode was added to the third neck of the flask. All electrodes were immersed in the spiked electrolyte in the flask. A linear sweep voltammetry (LSV) experiment was performed relative to a saturated mercurous chloride electrode, where the potential was swept from 1.3 V to 0.4 V. The voltage was swept at a rate of 1 mV / s. The resulting Br - The oxidation and Br2 reduction currents were measured as a function of voltage.

[0559] The maximum power obtained during Br2 reduction is calculated by multiplying the limiting current for Br2 reduction by the highest voltage obtained at the limiting current. The maximum power for Br2 reduction is generally achieved at around 0.4 V relative to a saturated mercurous chloride electrode.

[0560] Figures 32 to 34 The results of stability experiments and power experiments are provided in.

[0561] Example 1B - Electrochemical cell comprising the electrolyte formulation of Example 1A

[0562] refer to Figures 35 to 38 The selected electrolytes formulated as described in Example 1A above were added to dry electrochemical test cells, which were evaluated for discharge capacity, coulombic efficiency, run time, and energy efficiency as a function of the number of charge cycles. The dry cells used in the examples were Figure 1. Each test cell contains a CalgonCarbon Zorflex ACC FM-10 carbon cloth separator, which is cut into a rectangle (width of about 5.31 cm and length of about 12.076 cm) using a steel straight-grained die coated in ZrN of the same shape. The carbon material is formulated using 20 kg of PTFE dispersion (60 wt%) (DuPont DISP30 PTFE dispersion), 10 kg of Cabot PBX52 carbon black, 1 kg of carbon fiber (3 mm), 10 kg of Akzo-Nobel Ketjenblack EC600JD carbon black, and 10 kg of deionized water. The dry ingredients are premixed in a 55-gallon drum with an antistatic drum lining to form a relatively homogeneous mixture, the PTFE dispersion and deionized water are added to the mixture, and the resulting mixture is stirred to produce a dough-like material. The dough-like material is formed into a block (length about 5.24cm, width about 3.94cm, thickness about 3.7mm), and it is furnace dried to remove moisture to form a carbon material block. Three such blocks are added to the cathode holder in the test cell. The electrode plate and terminal plate are formed by the titanium metal coated with TiC (which can be commercially available from the titanium metal company (TitaniumMetalsCorporation, Exton, PA) in Exton, Pennsylvania) and are formed into a plate (length about 13.5cm, width about 8.375cm, thickness about 0.005cm) with 45 ° of chamfered corners. The cathode holder is stamped into a surface area (length about 5.187cm, width about 11.952cm) with a pocket portion, which is reduced, and the width of the peripheral edge of a flange to the peripheral edge of the relative flange by the cathode holder is obtained to obtain a total length of about 5.73cm and a total width of about 12.495cm, and a pocket depth of about 0.157cm. The adjusted hole pattern is chemically etched into the reduced surface area of ​​the pocket portion of the cathode holder using acid, wherein the centers of adjacent holes along the row are spaced about 0.065 cm in the x direction and each other row is spaced about 0.152 cm in the y direction. The cathode holder is loaded with a separator and 3 pieces of carbon material to form a cathode assembly, which is laser welded to the electrode plate with an offset of about 0.694 cm from the bottom edge of the electrode plate and an offset of about 0.502 cm from each side edge of the electrode plate. The cathode assembly is laser welded to the electrode plate along the flange of the cathode holder. On the surface of the bipolar electrode plate opposite to the cathode assembly, a conductive cup-shaped member is laser welded so that the center of the cup-shaped member is approximately aligned or centered with the center of the reduced surface of the cathode holder. Thus, the component is used as a terminal cathode assembly and a bipolar electrode of a test cell.The terminal anode assembly is similarly formed of a terminal end plate having substantially the same dimensions as the bipolar electrode plate, and an elliptical cup-shaped member is laser welded to the outer surface of the terminal anode end plate so that the center of the cup-shaped member is approximately collinear with the center of the cup-shaped member of the terminal cathode assembly. The conductive cup-shaped member is formed of a stamped titanium carbide material. The test cell is finally assembled by inserting a single high-density polyethylene frame member having a sealing ring fixed therein between the terminal anode assembly and the terminal cathode assembly and pressing the components between two opposing 6061-T6 aluminum press plates. The dry test cell is constructed using the selected electrolyte described above and loaded to a certain capacity. For these experiments, a control electrolyte No. 1 as described in Example 2 was used in the control electrochemical cell.

[0563] During battery cycling, the battery was charged to a capacity of 750 mAh and operated at 20 mA / cm 2 Discharge below. Figures 35 to 38 The results of the tests are provided in .

[0564] Example 2: Electrolyte formulation No. 2-1

[0565] Bipolar Static (Non-Flow) Battery Testing:

[0566] exist Figures 18 to 20 The following electrolyte formulations were tested in the battery pack shown in .

[0567] Each of the 28 bipolar electrodes of the battery pack contained a Calgon Carbon Zorflex ACC FM-10 carbon cloth separator, which was cut into rectangular shapes (about 5.31 cm in width and about 12.076 cm in length) using a steel straight-grained die coated in ZrN of the same shape. The carbon material was formulated using 20 kg of PTFE dispersion (60 wt%) (DuPont DISP30 PTFE dispersion), 10 kg of Cabot PBX52 carbon black, 1 kg of carbon fiber (3 mm), 10 kg of Akzo-Nobel Ketjenblack EC600JD carbon black, and 10 kg of deionized water. The dry ingredients were premixed in a 55-gallon drum with an antistatic drum liner to form a relatively homogeneous mixture, the PTFE dispersion and deionized water were added to the mixture, and the resulting mixture was stirred to produce a dough-like material. The dough-like material is formed into a block (length about 5.24cm, width about 3.94cm, thickness about 3.7mm), and it is furnace dried to remove moisture to form a carbon material block. Three such blocks are added to the cathode holder in the test cell. The bipolar electrode plate is formed by the titanium metal coated with TiC (which can be commercially available from the titanium metal company (Titanium Metals Corporation, Exton, PA) in Exton, Pennsylvania) and is formed into a plate (length about 13.5cm, width about 8.375cm, thickness about 0.005cm) with 45 ° of chamfered corners. The cathode holder is stamped into a surface area (length about 5.187cm, width about 11.952cm) with pocket part, reduced, and the width of the peripheral edge of a flange to the peripheral edge of the relative flange by the cathode holder is obtained to obtain a total length of about 5.73cm and a total width of about 12.495cm, and a pocket depth of about 0.157cm. The adjusted hole pattern was chemically etched into the reduced surface area of ​​the pocket portion of the cathode holder using acid, wherein the centers of adjacent holes along a row were spaced about 0.065 cm in the x-direction and each other row was spaced about 0.152 cm in the y-direction. The cathode holder was loaded with a separator and 3 pieces of carbon material to form a cathode assembly, which was laser welded to the electrode plate with an offset of about 0.694 cm from the bottom edge of the electrode plate and an offset of about 0.502 cm from each side edge of the electrode plate. The cathode assembly was laser welded to the electrode plate along the flange of the cathode holder.

[0568] The terminal cathode assembly is formed by laser welding a conductive cup-shaped member to a bipolar electrode as described above on the side opposite to the cathode assembly, so that the center of the cup-shaped member is approximately aligned or centered with the center of the reduced surface of the cathode assembly. The terminal anode assembly is similarly formed by a terminal end plate having substantially the same size as the bipolar electrode plate, and its elliptical cup-shaped member is laser welded to the outer surface of the terminal anode end plate so that the center of the cup-shaped member is approximately collinear with the center of the cup-shaped member of the terminal cathode assembly. The conductive cup-shaped member is formed of a stamped titanium carbide material. A portion of the inner surface of the terminal anode end plate corresponding to the reduced surface of the terminal cathode assembly relative to the cathode assembly is sandblasted to provide a rough surface. The test battery pack is assembled by inserting a high-density polyethylene frame member between 1) the cathode terminal end plate and the bipolar electrode, 2) each bipolar electrode, and 3) the terminal anode end plate and the bipolar electrode, thereby requiring a total of 30 frame members. Each of the 30 frame members has a sealing ring located on its first surface and a sealing ring located on its second surface. Two opposing 6061-T6 aluminum platens are used as Figures 18 to 20 The tie rods and fasteners shown in Figure 2 compress the 30 frame members against adjacent components. The dry storage battery pack is constructed and loaded to a certain capacity using the electrolyte described below.

[0569] Control Electrolyte No. 1

[0570] The formulation of control electrolyte No. 1 is based on the formulation described in U.S. Patent No. 4,482,614. Control electrolyte No. 1 was formulated as follows:

[0571] Table 36: Formulation of Control Electrolyte No. 1

[0572] Element quantity weight% <![CDATA[ZnBr2]]> 675g 67.5 <![CDATA[NH4Cl]]> 100g 10 PEG 15g 1.5 water 210g 21 total: 1000g 100

[0573] Control electrolyte No. 2

[0574] The formulation of control electrolyte No. 2 is based on the formulation described by Yan, Jung Hoon, Yan, Hyeon Sun, Ra, Ho Won, et al. Effect of surfactants on the performance of zinc / bromine redox flow batteries: improvements in current efficiency and system stability, Journal of Power Sources 275 (2015) 294-297. Control electrolyte No. 2 was formulated as follows:

[0575] Table 37: Formulation of Control Electrolyte No. 2.

[0576] Element quantity weight% <![CDATA[ZnBr2]]> 507g 50.7 <![CDATA[ZnCl2]]> 68g 6.8 N-Methyl-N-ethylpyrrolidinium bromide 155g 15.5 water 270g 27 total: 1000g 100

[0577] Electrolyte preparation 2-1

[0578] The electrolyte of the present invention is prepared as follows:

[0579] Table 38: Test electrolyte formulation No. 2-1.

[0580] Element quantity <![CDATA[ZnBr2]]> 345g KBr 85.2g KCl 81.2g Tetraethylene glycol dimethyl ether 32.5g DME-PEG 2000 16.2g Tetraethylammonium bromide 25.5g MEMBr 8.5g Neopentyl glycol 16.2g Tert-Butanol 4.1g water 385g <![CDATA[SnCl2·2H2O]]> 10ppm In 10ppm

[0581] The pH of the electrolyte was adjusted to 3 using concentrated HBr.

[0582] For these tests, each electrolyte was loaded into two test battery packs to provide duplicate test data (i.e., n=2). Each of the test battery packs was initially charged at a constant voltage of 38.0V, terminating at 15 minutes or less than 100mA. Charging continued at a constant current of +7.16Amp, terminating at 58.5V or a total accumulated charge of 30Ah. The cells were discharged at a constant current of -8.0A, terminating at 33V.

[0583] result:

[0584] refer to Fig.28 , Fig.29A as well as Fig.29B , a graph of battery energy (watt-hours) as a function of the number of charge cycles shows that the test battery utilizing the test electrolytes retained greater charge and discharge energy after more charge cycles than any of the control electrolytes. Also, a graph of battery capacity (ampere-hours) as a function of the number of charge cycles shows that the test battery utilizing the 2-1 electrolyte formulation retained greater charge capacity after more charge cycles than any of the control electrolytes.

[0585] Example 3: Cathode Holder Hole Pattern

[0586] Negative Control - Two dry test cells were formed as described in Example 1 B, but the cathode holders in these two cells had a series of unadjusted holes in the pocket portion of the cathode holder. The dry test cells were loaded to capacity using Control Electrolyte No. 1 and charged.

[0587] Test Cells - Three dry test cells containing the adjusted hole pattern on the reduced surface of the pocket portion of the cathode holder were formed as described in Example 1 B. The dry test cells were loaded to capacity using Control Electrolyte No. 1 and charged.

[0588] refer to Figures 30A to 31C , after charging, the test cells were disassembled and evaluated for zinc plating on the anode surface of the cells. Fig. 30A and30B The negative control test cell shows the zinc plating Figures 31A to 31C Zinc plating on a test cell is shown. Figures 30A to 31C It is shown that enhanced zinc plating was observed for test cells formed from cathode holders having adjusted hole patterns on their respective pocket areas. Fig. 30A and 30B As shown, when the corresponding cathode holder has a series of unregulated holes, the zinc metal is deposited in an irregular pattern. Fig.31A , 31B When the corresponding cathode holder has a series of adjusted holes, zinc metal is deposited in a more regular and complete pattern, as shown in FIGS. 31A and 31C.

[0589] Example 4: Battery Pack Performance

[0590] refer to Fig.24 , 25A , 25B, 26, 27A and 27B, the test battery pack as described in Example 1 was subjected to charge / discharge cycles to evaluate the performance characteristics of the test battery pack. The data from the testing was plotted in the figures referenced in this Example 3.

[0591] Example 5: Alkylammonium bromides in electrolytes

[0592] The following electrolytes were prepared as follows:

[0593] Table 39: Electrolyte formulation No. 5-1.

[0594] Element Amount (g) weight% <![CDATA[ZnBr2]]> 85 34.71 water 95 38.79 KBr 21 8.57 KCl 20 8.17 Acetic acid 1.11 0.45 1-Ethyl-2-methylpyridinium bromide 9.92 4.05 Chloroethylammonium chloride 12.2 4.98 18-Crown-6 0.55 0.22 Hexadecyltrimethylammonium bromide 0.1 0.04 <![CDATA[SnCl2·2H2O]]> About 0.0047 About 0.0019 In(In in nitric acid solution) About 0.0025 About 0.0010 Nitric acid (from solution) About 0.026 About 0.0106 total: About 244.91 Approx. 100.00

[0595] Table 40: Electrolyte formulation No. 5-2.

[0596] Element Amount (g) weight% <![CDATA[ZnBr2]]> 85 34.73 water 95 38.82 KBr 21 8.58 KCl 20 8.17 Acetic acid 1.11 0.45 1-Ethyl-4-methylpyridinium bromide 9.92 4.05 Tetraethylammonium bromide 6.0 2.45 Trimethylpropylammonium bromide 6.0 2.45 18-Crown-6 0.55 0.22 Hexadecyltrimethylammonium bromide 0.1 0.04 <![CDATA[SnCl2·2H2O]]> About 0.0047 About 0.0019 In(In in nitric acid solution) About 0.0025 About 0.0010 Nitric acid (from solution) About 0.026 About 0.0106 total: About 244.71 Approx. 100.00

[0597] Table 41: Electrolyte formulation No. 5-3.

[0598] Element Amount (g) weight% <![CDATA[ZnBr2]]> 85 34.73 water 95 38.82 KBr 21 8.58 KCl 20 8.17 Acetic acid 1.11 0.45 1-Ethyl-4-methylpyridinium bromide 9.92 4.05 Tetraethylammonium bromide 6.0 2.45 Triethylmethylammonium bromide 6.0 2.45 18-Crown-6 0.55 0.22 Hexadecyltrimethylammonium bromide 0.1 0.04 <![CDATA[SnCl2·2H2O]]> About 0.0047 About 0.0019 In(In in nitric acid solution) About 0.0025 About 0.0010 Nitric acid (from solution) About 0.026 About 0.0106 total: About 244.71 Approx. 100.00

[0599] Table 42: Electrolyte formulation No. 5-4

[0600]

[0601]

[0602] Table 43: Electrolyte formulation No. 5-5.

[0603] Element Amount (g) weight% <![CDATA[ZnBr2]]> 85 34.73 water 95 38.82 KBr 21 8.58 KCl 20 8.17 Acetic acid 1.11 0.45 1-Ethyl-4-methylpyridinium bromide 9.92 4.05 Tetraethylammonium bromide 6.0 2.45 Triethyl-N-methoxymethylammonium bromide 6.0 2.45 18-Crown-6 0.55 0.22 Hexadecyltrimethylammonium bromide 0.1 0.04 <![CDATA[SnCl2·2H2O]]> About 0.0047 About 0.0019 In(In in nitric acid solution) About 0.0025 About 0.0010 Nitric acid (from solution) About 0.026 About 0.0106 total: About 244.71 Approx. 100.00

[0604] Each of the electrolytes in the examples was loaded into the dry battery pack described in Example 2.

[0605] Each of the test batteries was initially charged at a constant voltage of 38.0 V, terminating at 15 minutes or less than 100 mA. 2 The battery was then placed at -20.0 mA / cm 2 The battery was discharged at a constant current of 33 V and terminated at 33 V.

[0606] Fig.39 Graphs of cyclic voltammetry measurements for each of the test battery groups are provided in .

[0607] Example 6A:

[0608] Triethylmethylammonium bromide was evaluated as a replacement for tetraethylammonium bromide in the electrolyte formulation using electrolyte Nos. 1-32. Accordingly, electrolyte Nos. 1-32 were evaluated as follows.

[0609] During the preparation of electrolytes Nos. 1-32, it was noted that triethylmethylammonium bromide exhibited a surprisingly significant increase in solubility over tetraethylammonium bromide.

[0610] exist Figures 40 to 43 140mA / cm shown in 2 Electrolytes No. 1-32 were evaluated in test cells. These test cells are formed by a housing 600 including a reaction chamber 610 formed therein. Two slotted Teflon inserts 620, 630 are disposed in the reaction chamber at opposite sides so that the slots of the inserts face inward and are aligned with each other. Two L-shaped titanium current collector plates 640, 650 coated with titanium carbide or hot-injected with carbon are mounted in the slotted inserts so that one leg 660a, 660b of each L-shaped current collector plate is oriented vertically and the other leg 670a, 670b is oriented horizontally at the top of the reaction chamber and faces outward, thereby forming an electrolyte reservoir 680 together with the slotted inserts. Accordingly, the electrolyte reservoir is defined by two opposing side walls formed by the vertically oriented faces of the current collectors, two opposing side walls formed by the slotted inserts, and a bottom formed by the bottom of the reaction chamber. Carbon felt (Avcarb G150) 690 was bonded to the vertically oriented leg 660b of the L-shaped current collector plate 650 facing the electrolyte reservoir. The test cell also contained a Teflon cover 700 having a pressure release valve 710 and two through holes 720, 730 through which the electrodes were placed to make electrical contact with the horizontally oriented legs of the current collector plate.

[0611] refer to Fig.44 During the test, the volume of electrolyte No. 1-32 was kept constant (20 mL total) while evaluating battery performance at electrolyte depths of 6 mm (batteries 9182 and 9183) and 8 mm (batteries 9184 and 9185). Changes in electrolyte depth were accommodated by moving the L-shaped current collector plates to different slots, thereby narrowing the gap between the relative vertical faces of the current collector plates.

[0612] Each test was repeated (n=2)

[0613] refer to Fig.44 , the energy efficiency and coulombic efficiency of the test cells were evaluated over five cycles. The average energy efficiency of test cells 9182 and 9183 was calculated to be 71.2%, the average energy efficiency of test cells 9184 and 9185 was calculated to be 69.7%, the average coulombic efficiency of test cells 9182 and 9183 was calculated to be 92.5%, and the average coulombic efficiency of test cells 9184 and 9185 was calculated to be 93.1%. Accordingly, when the battery is charged at 140 mA / cm 2 When used in the charge capacity test cells, the 1-32 electrolyte exhibited higher coulombic efficiency and energy efficiency.

[0614] Example 6B:

[0615] Table 44: Electrolyte formulation No. 6-1.

[0616] Element Amount (g) weight% <![CDATA[ZnBr2]]> 85 34.92 water 95 39.03 KBr 5.3 2.18 KCl 29.8 12.24 Acetic acid 1.11 0.46 1-Ethyl-4-methylpyridinium bromide 9.92 4.08 Tetraethylammonium bromide 12.2 5.01 DME-PEG 2000 4 1.64 DME-PEG 1000 1 0.41 Hexadecyltrimethylammonium bromide 0.1 0.04 total: About 243.43 Approx. 100.00

[0617] 140 mA / cm described in Example 6A 2 The energy efficiency and coulombic efficiency of electrolyte No. 6-1 were evaluated in a test cell (Battery 9084) and compared to the test results from a corresponding cell (Battery 8084) using electrolyte No. 1-32.

[0618] refer to Fig.45 , the energy efficiency and coulombic efficiency of the test cells were evaluated over 25 cycles. The coulombic efficiency and energy efficiency of the 9084 cell were significantly greater than those of the 8084 cell. Accordingly, when the 2 When used in charge capacity test cells, the 6-1 electrolyte exhibited excellent coulombic efficiency and energy efficiency.

[0619] Example 6B:

[0620] Electrolyte No. 6-2 was prepared as follows:

[0621] Table 45: Electrolyte formulation No. 6-2.

[0622] Element Amount (g) weight% <![CDATA[ZnBr2]]> 85 34.92 water 95 39.03 KBr 5.3 2.18 KCl 29.8 12.24 Acetic acid 1.11 0.46 1-Ethyl-3-methylpyridinium bromide 9.92 4.08 Tetraethylammonium bromide 12.2 5.01 DME-PEG 2000 4 1.64 DME-PEG 1000 1 0.41 Hexadecyltrimethylammonium bromide 0.1 0.04 total: About 243.43 Approx. 100.00

[0623] refer to Fig.46 The test cells described above in Example 6A were subjected to cyclic voltammetry testing as described in Example 5, wherein one test cell was configured with 1-32 electrolyte, one test cell was configured with 6-1 electrolyte, and one test cell was configured with 6-2 electrolyte.

[0624] Example 7:

[0625] The following electrolyte formulations were prepared and evaluated in test cells as described above in Example 6A.

[0626] Table 46: Electrolyte formulation No. 7-1.

[0627]

[0628]

[0629] Table 47: Electrolyte formulation No. 7-2.

[0630] Element weight% <![CDATA[ZnBr2]]> 26.56 <![CDATA[H2O]]> 48.82 KBr 6.56 KCl 10.97 Methylethylmorpholinium bromide 0.99 Tetraethylammonium bromide 1.97 Triethylmethylammonium chloride 1.88 MPEG 2K 1.25 MPEG 1K 0.31 HBr 0.52 1,1-Dioctadecyl-4,4'-bipyridinium dibromide 0.11 Hexadecyltrimethylammonium bromide 0.06 Sn 7ppm In 7ppm total: Approx. 100.00

[0631] Table 48: Electrolyte formulation No. 7-3.

[0632] Element weight% <![CDATA[ZnBr2]]> 28.67 <![CDATA[H2O]]> 46.35 KBr 7.09 KCl 10.28 Methylethylmorpholinium bromide 1.08 Tetraethylammonium bromide 2.12 Triethylmethylammonium chloride 2.03 MPEG 2K 1.35 MPEG 1K 0.33 HBr 0.52 1,1-Dioctadecyl-4,4'-bipyridinium dibromide 0.11 Hexadecyltrimethylammonium bromide 0.06 Sn 7ppm In 7ppm total: Approx. 100.00

[0633] Each of the test cells produced using electrolytes 7-1, 7-2 or 7-3 exhibited energy efficiencies greater than 80%.

[0634] Example 8:

[0635] refer to Figures 47 to 52 , the following electrolyte formulations are Figure 1 The test cells were prepared and evaluated in a configuration as described in the above, wherein the terminal cathode plate was formed of a 0.020 inch thick TiC plate, with a 6.4 mm thick carbon felt (G250 ) (activated) was adhered to the active area of ​​the TiC plate using an adhesive consisting of 60 wt % acetone, 13.92 wt % polyvinylidene fluoride resin ( 2750-00), 7.52 wt% isobutyl methacrylate resin ( 4111), 16.16 wt% artificial graphite ( KS6), 2 wt% sodium hexametaphosphate, and 0.4 wt% polymethyl methacrylate (PMMA). The frame member is formed of machined HDPE. The battery was repeatedly cycled under the following conditions: at a constant power of 2.25 W and ramped to 5.5 W, a charging potential of 1.95 V, a charge capacity of 7.5 Ah cutoff and ramped to 15 Ah, a maximum charge rest time of 30 minutes and ramped to 24 hours, a discharge current of a constant power of 2.25 W and ramped to 5.5 W, a discharge voltage of 1.1 V, a minimum discharge rest time of 6 hours, and the test temperature was ambient temperature.

[0636] Table 49: Electrolyte formulation No. 8-1.

[0637] Element weight% <![CDATA[ZnBr2]]> 40.89 <![CDATA[H2O]]> 35.64 KBr 4.95 KCl 10.01 Triethylmethylammonium chloride 5.25 Tetraethylammonium bromide 0.99 MPEG 2K 1.14 MPEG 1K 0.32 Neopentyl glycol 0.90 <![CDATA[InCl3]]> 7ppm <![CDATA[SnCl2·2H2O]]> 7ppm HBr Adjust to pH 3 total: Approx. 100.00

[0638] Table 50: Electrolyte formulation No. 8-2.

[0639]

[0640]

[0641] Table 51: Electrolyte formulation No. 8-3

[0642] Element weight% <![CDATA[ZnBr2]]> 38.65 <![CDATA[H2O]]> 34.22 KBr 7.09 KCl 11.81 Triethylmethylammonium chloride 5.01 Tetraethylammonium bromide 0.95 MPEG 2K 1.08 MPEG 1K 0.30 Neopentyl glycol 0.86 <![CDATA[InCl3]]> 7ppm <![CDATA[SnCl2·2H2O]]> 7ppm HBr Adjust to pH 3 total: Approx. 100.00

[0643] Table 52: Electrolyte formulation No. 8-4.

[0644] Element weight% <![CDATA[ZnBr2]]> 39.29 <![CDATA[H2O]]> 34.78 KBr 4.80 KCl 9.70 Triethylmethylammonium chloride 6.72 Tetraethylammonium bromide 2.40 MPEG 2K 1.10 MPEG 1K 0.31 Neopentyl glycol 0.87 <![CDATA[InCl3]]> 7ppm <![CDATA[SnCl2·2H2O]]> 7ppm HBr Adjust to pH 3 total: Approx. 100.00

[0645] Table 53: Electrolyte formulation No. 8-5.

[0646]

[0647]

[0648] Table 54: Electrolyte formulations No. 8-6.

[0649] Element weight% <![CDATA[ZnBr2]]> 39.98 <![CDATA[H2O]]> 35.39 KBr 4.88 KCl 9.87 Triethylmethylammonium chloride 5.18 Tetraethylammonium bromide 0.97 MPEG 2K 1.12 MPEG 1K 0.31 Neopentyl glycol 2.25 <![CDATA[InCl3]]> 7ppm <![CDATA[SnCl2·2H2O]]> 7ppm HBr Adjust to pH 3 total: Approx. 100.00

[0650] Table 55: Electrolyte formulations No. 8-7.

[0651] Element weight% <![CDATA[ZnBr2]]> 40.41 <![CDATA[H2O]]> 35.78 KBr 4.94 KCl 9.98 Triethylmethylammonium chloride 5.23 Tetraethylammonium bromide 0.98 MPEG 2K 1.13 MPEG 1K 0.31 Neopentyl glycol 0.98 Tetraethylene glycol dimethyl ether 0.29 <![CDATA[InCl3]]> 7ppm <![CDATA[SnCl2·2H2O]]> 7ppm HBr Adjust to pH 3 total: Approx. 100.00

[0652] Example 9:

[0653] refer to Figures 53 to 58 , the following electrolyte formulations are Figure 1The test cells were prepared and evaluated in a configuration as described in the above, wherein the terminal cathode plate was formed of a 0.020 inch thick TiC plate, with a 6.4 mm thick carbon felt (G250 ) (activated) was adhered to the active area of ​​the TiC plate using an adhesive consisting of 60 wt % acetone, 13.92 wt % polyvinylidene fluoride resin ( 2750-00), 7.52 wt% isobutyl methacrylate resin ( 4111), 16.16 wt% artificial graphite ( KS6), 2 wt% sodium hexametaphosphate and 0.4 wt% polymethyl methacrylate (PMMA). The frame members were formed from machined HDPE. The cells were tested under repeated cycles at a constant power of 2.25 W and ramped to 5.5 W, a charge potential of 1.95 V, a charge capacity of 7.5 Ah cutoff and ramped to 15 Ah, a maximum charge rest time of 30 minutes and ramped to 24 hours, a discharge current of a constant power of 2.25 W and ramped to 5.5 W, a discharge voltage of 1.1 V, a minimum discharge rest time of 6 hours, and a test temperature of ambient temperature.

[0654] Table 56: Electrolyte formulation No. 9-1.

[0655] Element weight% <![CDATA[ZnBr2]]> 42.07 <![CDATA[H2O]]> 27.23 KBr 6.28 KCl 10.52 Triethylmethylammonium chloride 8.33 Tetraethylammonium bromide 2.98 MPEG 2K 1.06 MPEG 1K 0.30 Neopentyl glycol 0.84 <![CDATA[InCl3]]> 7ppm <![CDATA[SnCl2·2H2O]]> 7ppm HBr Adjust to pH 3 total: Approx. 100.00

[0656] Table 57: Electrolyte formulation No. 9-2.

[0657] Element weight% <![CDATA[ZnBr2]]> 42.07 <![CDATA[H2O]]> 27.23 KBr 3.01 KCl 13.84 Triethylmethylammonium chloride 8.33 Tetraethylammonium bromide 2.98 MPEG 2K 1.06 MPEG 1K 0.30 Neopentyl glycol 0.84 <![CDATA[InCl3]]> 7ppm <![CDATA[SnCl2·2H2O]]> 7ppm HBr Adjust to pH 3 total: Approx. 100.00

[0658] Table 58: Electrolyte formulation No. 9-3.

[0659] Element weight% <![CDATA[ZnBr2]]> 42.07 <![CDATA[H2O]]> 27.23 KBr 8.20 KCl 8.31 Triethylmethylammonium chloride 8.33 Tetraethylammonium bromide 2.98 MPEG 2K 1.06 MPEG 1K 0.30 Neopentyl glycol 0.84 <![CDATA[InCl3]]> 7ppm <![CDATA[SnCl2·2H2O]]> 7ppm HBr Adjust to pH 3 total: Approx. 100.00

[0660] Table 59: Electrolyte formulation No. 9-4.

[0661] Element weight% <![CDATA[ZnBr2]]> 42.07 <![CDATA[H2O]]> 27.23 KBr 6.28 KCl 10.52 Triethylmethylammonium chloride 8.33 Trimethylpropylammonium bromide 0.40 Tetraethylammonium bromide 2.48 MPEG 2K 1.06 MPEG 1K 0.30 Neopentyl glycol 0.84 <![CDATA[InCl3]]> 7ppm <![CDATA[SnCl2·2H2O]]> 7ppm HBr Adjust to pH 3 total: Approx. 100.00

[0662] Example 10:

[0663] refer to Figures 59 to 64 , the following electrolyte formulations are Figure 1 The test cells were prepared and evaluated in a configuration as described in the above, wherein the terminal cathode plate was formed of a 0.020 inch thick TiC plate, with a 6.4 mm thick carbon felt (G250 ) (activated) was adhered to the active area of ​​the TiC plate using an adhesive consisting of 60 wt % acetone, 13.92 wt % polyvinylidene fluoride resin ( 2750-00), 7.52 wt% isobutyl methacrylate resin ( 4111), 16.16 wt% artificial graphite ( KS6), 2 wt% sodium hexametaphosphate and 0.4 wt% polymethyl methacrylate (PMMA). The frame members were formed from machined HDPE. The cells were tested under repeated cycles at a constant power of 2.25 W and ramped to 5.5 W, a charge potential of 1.95 V, a charge capacity of 7.5 Ah cutoff and ramped to 15 Ah, a maximum charge rest time of 30 minutes and ramped to 24 hours, a discharge current of a constant power of 2.25 W and ramped to 5.5 W, a discharge voltage of 1.1 V, a minimum discharge rest time of 6 hours, and a test temperature of ambient temperature.

[0664] Table 60: Electrolyte formulation No. 10-1.

[0665] Element weight% <![CDATA[ZnBr2]]> 43.10 <![CDATA[H2O]]> 25.64 KBr 4.58 KCl 9.05 Triethylmethylammonium chloride 12.11 Tetraethylammonium bromide 2.73 Trimethylpropylammonium bromide 0.50 MPEG 2K 1.18 MPEG 1K 0.35 Neopentyl glycol 0.71 <![CDATA[InCl3]]> 7ppm <![CDATA[SnCl2·2H2O]]> 7ppm HBr Adjust to pH 3 total: Approx. 100.00

[0666] Table 60: Electrolyte formulation No. 10-2.

[0667] Element weight% <![CDATA[ZnBr2]]> 42.75 <![CDATA[H2O]]> 29.31 KBr 4.55 KCl 9.09 Triethylmethylammonium chloride 9.00 Tetraethylammonium bromide 2.00 Trimethylpropylammonium bromide 0.53 MPEG 2K 1.18 MPEG 1K 0.36 Neopentyl glycol 0.73 <![CDATA[InCl3]]> 7ppm <![CDATA[SnCl2·2H2O]]> 7ppm HBr Adjust to pH 3 total: Approx. 100.00

[0668] Table 61: Electrolyte formulation No. 10-3.

[0669]

[0670]

[0671] Table 62: Electrolyte formulation No. 10-4.

[0672] Element weight% <![CDATA[ZnBr2]]> 42.75 <![CDATA[H2O]]> 28.11 KBr 3.00 KCl 8.00 Triethylmethylammonium chloride 12.60 Tetraethylammonium bromide 2.73 Trimethylpropylammonium bromide 0.53 MPEG 2K 1.18 MPEG 1K 0.36 Neopentyl glycol 0.73 <![CDATA[InCl3]]> 7ppm <![CDATA[SnCl2·2H2O]]> 7ppm HBr Adjust to pH 3 total: Approx. 100.00

[0673] Table 63: Electrolyte formulation No. 10-5.

[0674]

[0675]

[0676] Example 11:

[0677] Electrolyte 11-1 is configured as described in Table 64:

[0678] Table 64: Electrolyte formulation No. 11-1.

[0679] Element weight% <![CDATA[ZnBr2]]> 39.00 <![CDATA[H2O]]> 34.49 KBr 4.75 KCl 9.62 Triethylmethylammonium chloride 6.66 Tetraethylammonium bromide 2.38 MPEG 2K 1.09 MPEG 1K 0.30 Neopentyl glycol 1.49 Tetraethylene glycol dimethyl ether 0.25 <![CDATA[InCl3]]> 7ppm <![CDATA[SnCl2·2H2O]]> 7ppm HBr Adjust to pH 3 total: Approx. 100.00

[0680] Other embodiments

[0681] It will be apparent that the foregoing relates only to the preferred embodiments of the present invention and that numerous changes and modifications may be made therein without departing from the spirit and scope of the present invention as defined by the appended claims and their equivalents.

Claims

1. An electrolyte for use in a bipolar, static secondary zinc bromide electrochemical cell, comprising: 25 to 70 wt % ZnBr2; 5 to 50 wt. % water; 0.5 wt% to 5 wt% C 2-10 diols; 1 to 15 wt % KBr; 5 to 20 wt % KCl; 0.5 wt % to 2.5 wt % DME-PEG; and one or more quaternary ammonium agents, wherein the electrolyte comprises 0.05 wt % to 10 wt % of the one or more quaternary ammonium agents, and wherein each quaternary ammonium agent is independently selected from a group consisting of A quaternary ammonium agent wherein R1, R2, R3 and R4 are each independently selected from hydrogen or an alkyl group, and Y is chlorine or bromine.

2. The electrolyte according to claim 1, comprising: 5 to 15 wt% KBr.

3. The electrolyte according to claim 1 or 2, further comprising 1.5 wt % to 7.5 wt % ZnCl2.

4. The electrolyte according to claim 1 or 2, comprising 30 to 45 wt% of water.

5. The electrolyte according to claim 1 or 2, comprising 35 to 41 wt% of water. 6 . The electrolyte according to claim 1 , further comprising 0.5 to 10 wt % of glyme. 7 . The electrolyte of claim 6 , wherein the glyme comprises monoglyme, diglyme, triglyme, tetraglyme, pentaglyme, hexaglyme, or any combination thereof.

8. The electrolyte according to claim 1, wherein the DME-PEG has an average molecular weight of 350 to 3000 amu. 9 . The electrolyte according to claim 1 , wherein the DME-PEG has an average molecular weight of 1200 to 3000 amu.

10. The electrolyte according to claim 8 or 9, comprising 1 wt% to 2 wt% of DME-PEG 2000, 0.5 wt% to 0.75 wt% of DME-PEG 1000, or a combination thereof.

11. The electrolyte according to claim 1 or 2, further comprising 0.1 wt% to 1.0 wt% of an alcohol, wherein the alcohol is miscible in water.

12. The electrolyte according to claim 11, wherein the alcohol comprises C 1-4 alcohol.

13. The electrolyte of claim 1 or 2, wherein the diol comprises ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, hexylene glycol, or any combination thereof.

14. The electrolyte of claim 1 or 2, wherein the one or more quaternary ammonium agents include a quaternary ammonium agent selected from the group consisting of: Tetraethylammonium bromide, trimethylpropylammonium bromide, N-methyl-N-ethylmorpholinium bromide, N-methyl-N-ethylmorpholinium bromide, 1-ethyl-1-methylmorpholinium bromide, N-methyl-N-butylmorpholinium bromide, N-methyl-N-ethylpyrrolidinium bromide, N,N,N-triethyl-N-propylammonium bromide, N-ethyl-N-propylpyrrolidinium bromide, N-propyl-N-butylpyrrolidinium bromide, N-methyl-N-butylpyrrolidinium bromide, 1-methyl-1-butylpyrrolidinium bromide, N-ethyl-N-(2-chloroethyl)pyrrolidinium bromide, N-methyl The invention can be any of the following: trimethyl-N-hexylpyrrolidinium bromide, N-methyl-N-pentylpyrrolidinium bromide, N-ethyl-N-pentylpyrrolidinium bromide, N-ethyl-N-butylpyrrolidinium bromide, trimethyl-bis(N-methylpyrrolidinium) dibromide, N-butyl-N-pentylpyrrolidinium bromide, N-methyl-N-propylpyrrolidinium bromide, N-propyl-N-pentylpyrrolidinium bromide, 1-ethyl-4-methylpyridinium bromide, 1-ethyl-2-methylpyridinium bromide, 1-butyl-3-methylpyridinium bromide, hexadecyltrimethylammonium bromide, and any combination thereof.

15. The electrolyte of claim 1 or 2, wherein the one or more quaternary ammonium agents comprise (i) 3.5 to 4.5 wt % of 1-ethyl-4-methylpyridinium bromide; (ii) 1 to 7 wt % of 1-ethyl-2-methylpyridinium bromide; (iii) 1.5 to 2.5 wt % of 1-methyl-1-butylpyrrolidinium bromide; (iv) 1.5 to 2.5 wt % of 1-butyl-3-methylpyridinium bromide; (v) 0.5% to 1.5% by weight of N-methyl-N-ethylmorpholinium bromide; (vi) 2 to 3 wt % of trimethylpropylammonium bromide; (vii) 2 to 8 wt % tetraethylammonium bromide; (viii) 0.05% to 0.2% by weight of cetyltrimethylammonium bromide; or (ix) any combination of the above.

16. The electrolyte of claim 1 or 2, further comprising less than 1 wt% of one or more additives, wherein the one or more additives are selected from Sn, In, Ga, Al, Tl, Bi, Pb, Sb, Ag, Mn, or Fe.

17. The electrolyte of claim 16, wherein the one or more additives are selected from 0.0008 wt% to 0.0012 wt% SnCl2.H2O, 0.0008 wt% to 0.0012 wt% In, and combinations thereof.

18. The electrolyte according to claim 1 or 2, further comprising an acid or a conjugate base of an acid selected from acetic acid, nitric acid and citric acid.

19. The electrolyte according to claim 1 or 2, further comprising 0.3 wt% to 0.6 wt% of acetic acid, 0.12 wt% to 0.08 wt% of nitric acid, 3.5 wt% to 4.5 wt% of citric acid, or 3.5 wt% to 4.5 wt% of potassium dihydrogen citrate.

20. The electrolyte of claim 1 or 2, comprising 0.05 to 0.75 wt% of the crown ether.

21. The electrolyte of claim 1 or 2, comprising 0.15 wt% to 0.5 wt% 18-crown-6, 0.05 wt% to 0.2 wt% 15-crown-5, or a combination of 0.15 wt% to 0.5 wt% 18-crown-6 and 0.05 wt% to 0.2 wt% 15-crown-5.

22. A method of preparing an electrolyte for use in a static secondary zinc-halogen electrochemical cell, comprising: Mix ZnBr2, KBr, KCl, C in water 2-10 diol, an ether selected from DME-PEG, dimethyl ether or any combination thereof, and one or more quaternary ammonium agents to form a mixture and stirring the mixture until the solids have dissolved, wherein the mixture comprises: 27 to 40 wt % ZnBr2; 7.3 wt % to 9.2 wt % KBr; 7 to 17 wt % KCl; 0.5 wt% to 5 wt% C 2-10 diols; 0.5 wt % to 2.5 wt % DME-PEG; 0.05 wt % to 20 wt % of the one or more quaternary ammonium agents, wherein each quaternary ammonium agent is independently selected from a group consisting of A quaternary ammonium agent wherein R1, R2, R3 and R4 are each independently selected from hydrogen or an alkyl group, and Y is chlorine or bromine; and 35% to 41% by weight of water.

23. The electrolyte of claim 11, wherein the alcohol comprises methanol, ethanol, 1-propanol, isopropanol, 1-butanol, sec-butanol, isobutanol, tert-butanol, or any combination thereof.

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