ELECTROLYTE FOR RECHARGEABLE ELECTROCHEMICAL CELL
The present invention provides an aqueous electrolyte for use in rechargeable zinc-halide storage batteries that possesses improved stability and durability and improves zinc-halide battery performance. One aspect of the present invention provides an electrolyte for use in a secondary zinc bromine electrochemical cell comprising from about 30 wt % to about 40 wt % of ZnBr 2 by weight of the electrolyte; from about 5 wt % to about 15 wt % of KBr; from about 5 wt % to about 15 wt % of KCl; and one or more quaternary ammonium agents, wherein the electrolyte comprises from about 0.5 wt % to about 10 wt % of the one or more quaternary ammonium agents.
1 . An electrolyte for use in a secondary zinc bromine electrochemical cell comprising:
from about 25 wt % to about 70 wt % of ZnBr 2 ;
from about 5 wt % to about 50 wt % of water; and
one or more quaternary ammonium agents,
wherein the electrolyte comprises from about 0.05 wt % to about 10 wt % of the one or more quaternary ammonium agents.
2 . The electrolyte according to claim 1 , further comprising:
from about 1 wt % to about 15 wt % of KBr;
from about 5 wt % to about 20 wt % of KCl.
3 . The electrolyte according to claim 1 or claim 2 , comprising from about 27 wt % to about 40 wt % of ZnBr 2 .
4 . The electrolyte according to any one of claims 1 - 3 , comprising from about 28 wt % to about 37 wt % of ZnBr 2 .
5 . The electrolyte according to any one of claims 1 - 4 , comprising from about 1.5 wt % to about 7.5 wt % of ZnCl 2 .
6 . The electrolyte according to any one of claims 1 - 5 , comprising from about 30 wt % to about 45 wt % of water.
7 . The electrolyte according to any one of claims 1 - 6 , comprising from about 35 wt % to about 41 wt % of water.
8 . The electrolyte according to any one of claims 1 - 7 , comprising from about 2 wt % to about 10 wt % of KBr.
9 . The electrolyte according to any one of claims 1 - 8 , comprising from about 7.3 wt % to about 9.2 wt % of KBr.
10 . The electrolyte according to any one of claims 1 - 9 , comprising from about 7 wt % to about 17 wt % of KCl.
11 . The electrolyte according to any one of claims 1 - 10 , further comprising from about 0.5 wt % to about 10 wt % of a glyme.
12 . The electrolyte according to claim 11 , wherein the glyme comprises monoglyme, diglyme, triglyme, tetraglyme, pentaglyme, hexaglyme, or any combination thereof.
13 . The electrolyte according to claim 11 or claim 12 , wherein the glyme comprises tetraglyme.
14 . The electrolyte according to any one of claims 11 - 13 , comprising from about 2 wt % to about 4 wt % of tetraglyme.
15 . The electrolyte according to any one of claims 1 - 14 , comprising from about 0.5 wt % to about 2.5 wt % of an ether selected from DME-PEG, dimethyl ether, or any combination thereof.
16 . The electrolyte according to claim 15 , wherein the electrolyte comprises DME-PEG, and the DME-PEG has an average molecular weight of from about 350 amu to about 3000 amu.
17 . The electrolyte according to claim 15 or claim 16 , wherein the DME-PEG has an average molecular weight of from about 1200 amu to about 3000 amu.
18 . The electrolyte according to any one of claims 15 - 17 , wherein the DME-PEG is DME-PEG 2000, DME-PEG 1000, or a combination thereof.
19 . The electrolyte according to any one of claims 15 - 18 , comprising from about 1 wt % to about 2 wt % DME-PEG 2000.
20 . The electrolyte according to any one of claims 15 - 19 , comprising from about 0.25 wt % to about 0.75 wt % DME-PEG 1000.
21 . The electrolyte according to any one of claims 15 - 20 , comprising from about 1 wt % to about 2 wt % DME-PEG 2000 and from about 0.25 wt % to about 0.75 wt % DME-PEG 1000.
22 . The electrolyte according to any one of claims 1 - 21 , further comprising from about 0.1 wt % to about 1.0 wt % of an alcohol, wherein the alcohol is substantially miscible in water.
23 . The electrolyte according to claim 22 , wherein the alcohol comprises a C 1-4 alcohol.
24 . The electrolyte according to claim 22 or claim 23 , wherein the alcohol comprises methanol, ethanol, 1-propanol, iso-propanol, 1-butanol, sec-butanol, iso-butanol, tert-butanol, or any combination thereof.
25 . The electrolyte according to any one of claims 22 - 24 , comprising from about 0.25 wt % to about 0.75 wt % of tert-butanol.
26 . The electrolyte according to any one of claims 1 - 25 , further comprising from about 0.5 wt % to about 5 wt % of a C 1-10 glycol.
27 . The electrolyte according to claim 26 , wherein the glycol comprises ethylene glycol, propylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, neopentyl glycol, hexalene glycol, or any combination thereof.
28 . The electrolyte according to claim 26 or claim 27 , comprising from about 0.25 wt % to about 2.5 wt % of neopentyl glycol.
29 . The electrolyte according to any one of claims 1 - 28 , further comprising from about 0.05 wt % to about 20 wt % of one or more quaternary ammonium agents.
30 . The electrolyte according to claim 29 , wherein the one or more quaternary ammonium agents comprises a 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), 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-N-hexylpyrrolidinium bromide, N-methyl-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, 1-ethyl-4-methylpyridinium bromide, 1-ethyl-2-methylpyridinium bromide, 1-butyl-3-methylpyridinium bromide, cetyltrimethylammonium bromide, and any combination thereof.
31 . The electrolyte according to claim 30 , wherein the one or more quaternary ammonium agents comprises a quaternary ammonium agent selected from the group consisting of ammonium chloride, tetraethylammonium bromide, trimethylpropylammonium bromide, N-methyl-N-ethylmorpholinium bromide (MEMBr), 1-ethyl-1-methylmorpholinium bromide, 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, cetyltrimethylammonium bromide, and any combination thereof.
32 . The electrolyte according to any one of claims 29 - 31 , wherein the one or more quaternary ammonium agents comprises about 3.5 wt % to about 4.5 wt % 1-ethyl-4-methylpyridinium bromide.
33 . The electrolyte according to any one of claims 29 - 32 , wherein the one or more quaternary ammonium agents comprises about 1 wt % to about 7 wt % 1-ethyl-2-methylpyridinium bromide.
34 . The electrolyte according to any one of claims 29 - 33 , wherein the one or more quaternary ammonium agents comprises about 1.5 wt % to about 2.5 wt % 1-methyl-1-butylpyrrolidinium bromide.
35 . The electrolyte according to any one of claims 29 - 34 , wherein the one or more quaternary ammonium agents comprises about 1.5 wt % to about 2.5 wt % 1-butyl-3-methylpyridinium bromide.
36 . The electrolyte according to any one of claims 29 - 35 , wherein the one or more quaternary ammonium agents comprises about 1.5 wt % to about 5 wt % 1-methyl-1-ethylmorpholinium bromide.
37 . The electrolyte according to any one of claims 29 - 36 , wherein the one or more quaternary ammonium agents comprises about 0.5 wt % to about 1.5 wt % N-methyl-N-ethylmorpholinium bromide (MEMBr).
38 . The electrolyte according to any one of claims 29 - 37 , wherein the one or more quaternary ammonium agents comprises about 14.5 wt % to about 16.5 wt % N-methyl-N-ethylpyrrolidinium bromide.
39 . The electrolyte according to any one of claims 29 - 38 , wherein the one or more quaternary ammonium agents comprises about 2 wt % to about 3 wt % trimethylpropylammonium bromide.
40 . The electrolyte according to any one of claims 29 - 39 , wherein the one or more quaternary ammonium agents comprises about 2 wt % to about 8 wt % tetraethylammonium bromide.
41 . The electrolyte according to any one of claims 29 - 40 , wherein the one or more quaternary ammonium agents comprises about 0.05 wt % to about 0.2 wt % cetyltrimethylammonium bromide.
42 . The electrolyte according to any one of claims 1 - 41 , further comprising less than 1 wt % of one or more additives selected from Sn, In, Ga, Al, Tl, Bi, Pb, Sb, Ag, Mn, or Fe.
43 . The electrolyte according to claim 42 , wherein the one or more additives are selected from about 0.0008 wt % to about 0.0012 wt % of SnCl 2 .H 2 O, from about 0.0008 wt % to about 0.0012 wt % of In, and combinations thereof.
44 . The electrolyte according to any one of claims 1 - 43 , further comprising an acid, or the conjugate base of an acid, selected from acetic acid, nitric acid, and citric acid.
45 . The electrolyte according to claim 44 , comprising from about 0.3 wt % to about 0.6 wt % acetic acid.
46 . The electrolyte according to claim 44 or claim 45 , comprising from about 0.12 wt % to about 0.08 wt % nitric acid.
47 . The electrolyte according to any one of claims 44 - 46 , comprising from about 3.5 wt % to about 4.5 wt % citric acid.
48 . The electrolyte according to any one of claims 44 - 47 , comprising from about 3.5 wt % to about 4.5 wt % potassium dihydrogen citrate.
49 . The electrolyte according to any one of claims 1 - 48 , comprising from about 0.05 wt % to about 0.75 wt % of a crown ether.
50 . The electrolyte according to claim 49 , comprising from about 0.15 wt % to about 0.5 wt % of 18-crown-6.
51 . The electrolyte according to claim 49 or claim 50 , comprising from about 0.05 wt % to about 0.2 wt % of 15-crown-5.
52 . An electrolyte for use in a secondary zinc halide electrochemical cell comprising:
from about 27 wt % to about 40 wt % of ZnBr 2 by weight of the electrolyte;
from about 35 wt % to about 41 wt % of water;
from about 7.3 wt % to about 9.2 wt % of KBr;
from about 7 wt % to about 17 wt % of KCl;
from about 0.3 wt % to about 0.6 wt % acetic acid; and
from about 2 wt % to about 8 wt % tetraethylammonium bromide.
53 . The electrolyte according to claim 52 , further comprising from about 0.05 wt % to about 0.2 wt % of cetyltriethylammonium bromide (CTAB).
54 . The electrolyte according to claim 52 or claim 53 , further comprising from about 3.5 wt % to about 4.5 wt % of citric acid monohydrate.
55 . The electrolyte according to any one of claims 52 - 54 , further comprising from about 3.5 wt % to about 4.5 wt % of potassium dihydrogen citrate monohydrate.
56 . An electrolyte for use in a secondary zinc halide electrochemical cell comprising:
from about 27 wt % to about 40 wt % of ZnBr 2 by weight of the electrolyte;
from about 35 wt % to about 41 wt % of water;
from about 7.3 wt % to about 9.2 wt % of KBr;
from about 7 wt % to about 17 wt % of KCl;
from about 0.15 wt % to about 0.5 wt % of 18-crown-6; and
from about 0.05 wt % to about 0.2 wt % cetyltrimethylammonium bromide.
57 . The electrolyte according to claim 56 , further comprising from about 2 wt % to about 8 wt % tetraethylammonium bromide.
58 . The electrolyte according to claim 56 or claim 57 , further comprising from about 0.3 wt % to about 0.6 wt % acetic acid.
59 . The electrolyte according to any one of claims 56 - 58 , comprising from about 1 wt % to about 2 wt % DME-PEG 2000.
60 . The electrolyte according to any one of claims 56 - 59 , comprising from about 0.25 wt % to about 0.75 wt % DME-PEG 1000.
61 . The electrolyte according to any one of claims 56 - 60 , comprising from about 1 wt % to about 2 wt % DME-PEG 2000 and from about 0.25 wt % to about 0.75 wt % DME-PEG 1000.
62 . A method of preparing an electrolyte for use in a secondary zinc halide electrochemical cell comprising:
mixing ZnBr 2 , KBr, KCl, and one or more quaternary ammonium agents under aqueous conditions to generate a mixture and stirring the mixture until the solids have dissolved,
wherein the mixture comprises:
from about 27 wt % to about 40 wt % of ZnBr 2 ;
from about 7.3 wt % to about 9.2 wt % of KBr;
from about 7 wt % to about 17 wt % of KCl;
from about 0.05 wt % to about 20 wt % of the one or more quaternary ammonium agents; and
from about 35 wt % to about 41 wt % of water.