Applications of low-cost, thermal and electrochemically stable organic compounds as high performance redox active materials in redox flow batteries
Described herein are redox active materials based on functionalization of 2,5-di(pyridine-4-yl)thiazolo-[5,4-d]thiazole (Py 2 TTz). Also described herein are aqueous organic redox flow batteries that include a first redox active material and a second redox active material comprising a viologen compound or a salt thereof.
1. A compound of formula (I):
or a salt thereof, wherein:
m is 1, 2, or 3;
each A is independently selected from arylene or heteroarylene;
L 1 and L 2 are C 1 -C 10 -alkyl;
n, at each occurrence, is independently 1, 2, or 3;
R 1 and R 2 are independently selected from the group consisting of —NO 2 , —OR a , —C(O)R b , —C(O)OR c , —S(O) q , —PO 3 , —S(O) q R d , —S(O) q OR e , —OP(O)(OR f ) 2 ; —OCH 2 , —P(O)(OR g ) 2 , —CHO, —(CR h 2 ) q CN, —N(R i ) q , and —P(R j ) r ;
each R a , R b , R c , R d , R e , R f , R g , R h , R i and R j are independently selected from the group consisting of hydrogen, C 1 -C 4 alkyl, cycloalkyl, heterocyclyl, aryl, heteroaryl, C 1 -C 4 alkyl-N(R k ) w , C 1 -C 4 alkyl-S(O) w , an oxygen protecting group, and a nitrogen protecting group;
R k , at each occurrence, is independently selected from the group consisting of hydrogen, alkyl, cycloalkyl, heterocyclyl, aryl, heteroaryl, an oxygen protecting group, and a nitrogen protecting group;
q, at each occurrence, is independently 2 or 3;
r, at each occurrence, is independently 2, 3, or 4; and
w, at each occurrence, is independently 2 or 3;
wherein each aryl, heteroaryl, arylene, heteroarylene, cycloalkyl, and heterocyclyl is independently unsubstituted or substituted.
2. A compound of claim 1 , wherein A is selected from the group consisting of:
3. The compound of claim 1 , wherein m is 2 and A is a five-membered or six-membered arylene or heteroarylene.
4. The compound of claim 1 , wherein A is selected from the group consisting of:
5. The compound of claim 1 , wherein R 1 and R 2 are independently selected from the group consisting of —S(O) q , —PO 3 , —S(O) q R d , and —N(R i ) q .
6. The compound of claim 1 , wherein each R a , R b , R c , R d , R e , R f , R g , R h , R i and R j are independently selected from hydrogen and C 1 -C 4 alkyl.
7. The compound of claim 1 , wherein the compound is a salt of fluoride, chloride, bromide, iodide, hydroxide, sulfate, carbonate, chlorate, perchlorate, phosphate, dihydrogen phosphate, hydrogen phosphate, nitrate, nitride, nitrile, dicyanamide, thiocyanate, bis(trifluoromethane)sulfonamide, hexafluorophosphate, tetrafluorophosphite, or a combination thereof.
8. A redox flow battery comprising:
a first redox active material; and
a second redox active material comprising a viologen or a salt thereof, wherein the viologen has formula (I):
wherein:
m is 1, 2, or 3;
each A is independently selected from arylene or heteroarylene;
L 1 and L 2 are C 1 -C 10 -alkyl;
n, at each occurrence, is independently 1, 2, or 3;
R 1 and R 2 are independently selected from the group consisting of —CH 3 , —NO 2 , —OR a , —C(O)R b , —C(O)OR c , —S(O) q , —PO 3 , —S(O) q R d , —S(O) q OR e , —OP(O)(OR f ) 2 ; —OCH 2 , —P(O)(OR g ) 2 , —CHO, —(CR h 2 ) q CN, —N(R i ) q , and —P(R j ) r
each R a , R b , R c , R d , R e , R f , R g , R h , R i and R j are independently selected from the group consisting of hydrogen, C 1 -C 4 alkyl, cycloalkyl, heterocyclyl, aryl, heteroaryl, C 1 -C 4 alkyl-N(R k ) w , C 1 -C 4 alkyl-S(O) w , an oxygen protecting group, and a nitrogen protecting group;
R k , at each occurrence, is independently selected from the group consisting of hydrogen, alkyl, cycloalkyl, heterocyclyl, aryl, heteroaryl, an oxygen protecting group, and a nitrogen protecting group;
q, at each occurrence, is independently 2 or 3;
r, at each occurrence, is independently 2, 3, or 4; and
w, at each occurrence, is independently 2 or 3;
wherein each aryl, heteroaryl, arylene, heteroarylene, cycloalkyl, and heterocyclyl is independently unsubstituted or substituted.
9. A redox flow battery of claim 8 , wherein A is selected from the group consisting of:
10. The redox flow battery of claim 8 , wherein m is 2 and A is a five-membered or six-membered arylene or heteroarylene.
11. The redox flow battery of claim 8 , wherein A is:
12. The redox flow battery of claim 8 , wherein R 1 and R 2 are independently selected from the group consisting of —S(O) q , —PO 3 , —S(O) q R d , and —N(R i ) q .
13. The redox flow battery of claim 8 , wherein each R a , R b , R c , R d , R e , R f , R g , R h , R i and R j are independently selected from hydrogen and C 1 -C 4 alkyl.
14. The redox flow battery of claim 8 , wherein the compound is a salt of fluoride, chloride, bromide, iodide, hydroxide, sulfate, carbonate, chlorate, perchlorate, phosphate, dihydrogen phosphate, hydrogen phosphate, nitrate, nitride, nitrile, dicyanamide, thiocyanate, bis(trifluoromethane)sulfonamide, hexafluorophosphate, tetrafluorophosphite, or a combination thereof.
15. The redox flow battery of claim 8 , wherein the first redox active material comprises − [Fe(CN) 6 ] 3+/2+ , I 3 − /I − , Br 2 /Br − , S 4 − /S 2 , KBr, NaBr, NH 4 Br, KI, NaI, NH 4 I, FeCl 2 , FeBr 2 , Ce 4+/3+ , Mn 3+/2+ , PbO 2 /PbSO 4 , quinone, a derivative of quinone, anthraquinone, a derivative of anthraquinone, K 4 [Fe(CN) 6 ], N 4 [Fe(CN) 6 ], (NH 4 ) 4 [Fe(CN) 6 ], Ni(OH) 2 , V 5+/4+ , (2,2,6,6-Tetramethylpiperidin-1-yl)oxyl (TEMPO), a derivative of TEMPO, or a combination thereof.
16. The redox flow battery of claim 15 , wherein the derivative of TEMPO is selected from the group consisting of 4-trimethylammonium-(2,2,6,6-Tetramethylpiperidin-1-yl)oxy (4-N Me -TEMPO), 4-dimethyl(propyl-3-N,N,N,-trimethylammonium)-(2,2,6,6-Tetramethylpiperidin-1-yl)oxy ((4-N NPr -TEMPO), 4-hyoxyl-ammonium-(2,2,6,6-Tetramethylpiperidin-1-yl)oxy (4-OHTEMPO), 4-sulfonate-(2,2,6,6-Tetramethylpiperidin-1-yl)oxy (4-SO 3 -TEMPO), 4-amino-(2,2,6,6-Tetramethylpiperidin-1-yl)oxy (4-NH 2 -TEMPO), N,N,N,2,2,6,6-heptamethylpiperidinyloxy-4-ammonium chloride (N Me -TEMPO), and a combination thereof.
17. The redox flow battery of claim 8 , further comprising:
a first aqueous electrolyte;
a second aqueous electrolyte; and
a separator between the first and second aqueous electrolytes.
18. The redox flow battery of claim 17 , wherein the second redox active material is present in the second aqueous electrolyte at a concentration of ≥0.1 M.
19. The redox flow battery claim 17 , further comprising a first electrode in contact with the first aqueous electrolyte and a second electrode in contact with the second aqueous electrolyte.
20. The redox flow battery of claim 17 , wherein the separator is a porous separator.
21. The redox flow battery of claim 17 , wherein the separator is an anion exchange membrane or a cation exchange membrane.
22. The redox flow battery of claim 17 , wherein the first and second aqueous electrolytes each independently comprise a salt having the formula (IV):
A-B (II),
wherein:
A is Na + , K + , Li + , NR m 4 + , pyridinium, pyrrolidium, or imidazolium;
R m is independently selected from the group consisting of hydrogen, alkyl, cycloalkyl, heterocyclyl, aryl, and heteroaryl; and
B is halide anion, SO 4 2− , OH − , CO 3 2− , ClO 4 − , H 2 PO 4 − , HPO 4 2− , PO 4 3− , NO 3 − , N 3 − , CN − , N(CN) 2 − , or SCN − .
23. The redox flow battery of claim 17 , wherein the first and second electrolytes each independently comprise NaCl, KCl, or NH 4 Cl.
24. The redox flow battery of claim 17 , wherein the first and second aqueous electrolytes each independently comprise between about 0.5 M to about 5 M NaCl, KCl, or NH 4 Cl.
25. The redox flow battery of claim 17 , further comprising:
a first circulation loop comprising a first storage tank containing the first aqueous electrolyte, piping for transporting the first aqueous electrolyte, a chamber in which the first electrode is in contact with the first aqueous electrolyte, and a pump to circulate the first aqueous electrolyte through the first circulation loop;
a second circulation loop comprising a second storage tank containing the second aqueous electrolyte, piping for transporting the second aqueous electrolyte, a chamber in which the second electrode is in contact with the second aqueous electrolyte, and a pump to circulate the second aqueous electrolyte through the second circulation loop; and
control hardware and software.
26. A method of storing energy, comprising applying a potential difference across the first and second electrode of the redox flow battery of claim 8 , wherein the first redox active material is oxidized.
27. A method of releasing energy, comprising applying a potential difference across the first and second electrode of the redox flow battery of claim 8 , wherein the first redox active material is reduced.