Flow batteries incorporating active materials containing doubly bridged aromatic groups

1. A flow battery comprising:

a first half-cell containing a first electrolyte solution; and

a second half-cell containing a second electrolyte solution;

wherein at least one of the first electrolyte solution and the second electrolyte solution comprises:

an active material comprising a bridged compound having a structure of:

a coordination compound thereof, or a salt thereof;

wherein:

Ary 1 is a substituted aromatic ring or a substituted heteroaromatic ring, wherein the aromatic or heteroaromatic ring of Ary 1 is substituted with one or more of an alkyl substituted with one or more of hydroxyl, carboxyl, amine, or sulfonyl; C 2 -C 6 polyol; OR 3 ; SR 3 ; S(═O)R 3 ; S(═O) 2 R 3 ; NR 9 R 10 ; CH 2 (OCH 2 CH 2 ) x OCH 3 ; C(═O)R 4 ; and/or sulfonyl;

Ary 2 is an unsubstituted aromatic ring, an unsubstituted heteroaromatic ring, a substituted aromatic ring, or a substituted heteroaromatic ring, wherein, when substituted, the aromatic or heteroaromatic ring of Ary 2 is substituted with one or more of an alkyl substituted with one or more of hydroxyl, carboxyl, amine, or sulfonyl; C 2 -C 6 polyol; OR 3 ; SR 3 ; S(═O)R 3 ; S(═O) 2 R 3 ; NR 9 R 10 ; CH 2 (OCH 2 CH 2 ) x OCH 3 ; C(═O)R 4 ; and/or sulfonyl; and

Z is CR 1 R 2 , NR 8 , O, S, S(═O), or S(═O) 2 , wherein:

R 1 is H; unsubstituted or substituted Akyl; C 2 -C 6 polyol; OR 3 ; SR 3 ; S(═O)R 3 ; S(═O) 2 R 3 ; NR 9 R 10 ; CH 2 (OCH 2 CH 2 ) x OCH 3 ; or C(═O)R 4 ;

R 2 is an alkyl substituted with one or more of hydroxyl, carboxyl, amine, or sulfonyl; C 2 -C 6 polyol; OR 3 ; SR 3 ; S(═O)R 3 ; S(═O) 2 R 3 ; NR 9 R 10 ; CH 2 (OCH 2 CH 2 ) x OCH 3 ; or C(═O)R 4 ; and

R 3 is H; an alkyl substituted with one or more of hydroxyl, carboxyl, amine, or sulfonyl; (CH 2 CH 2 O) x CH 3 ; C(═O)NR 5 R 6 ; or C(═O)R 7 ; and

R 5 and R 6 are, independently, H; an alkyl substituted with one or more of hydroxyl, carboxyl, amine, or sulfonyl; (CH 2 CH 2 O) x CH 3 ; or CH 2 (OCH 2 CH 2 ) x OCH 3 ; and

R 7 is OH or an alkyl substituted with one or more of hydroxyl, carboxyl, amine, or sulfonyl; and

R 4 is R 5 , OR 5 , or NR 5 R 6 ; and

R 8 is H; an alkyl substituted with one or more of hydroxyl, carboxyl, amine, or sulfonyl; (CH 2 CH 2 O) x CH 3 ; CH 2 (OCH 2 CH 2 ) x OCH 3 ; C(═O)R 5 ; C(═O)OR 5 ; or C(═O)NR 5 R 6 ; and

R 9 and R 10 are, independently, H; an alkyl substituted with one or more of hydroxyl, carboxyl, amine, or sulfonyl; (CH 2 CH 2 O) x CH 3 ; or CH 2 (OCH 2 CH 2 ) x OCH 3 ; and

x is an integer ranging between 0 and 100.

2. The flow battery of claim 1 , wherein Z is NR 8 .

3. The flow battery of claim 1 , wherein:

Ary 1 is a substituted benzene ring, naphthyl ring, pyridine ring, pyrazine ring, pyrimidine ring, triazine ring, quinolone ring, isoquinoline ring, phthalazine ring, quinazoline ring, quinoxaline ring, thiophene ring, benzothiophene ring, pyrrole ring, indole ring, isoindole ring, pyrazole ring, indazole ring, imidazole ring, benzimidazole ring, triazole ring, benzotriazole ring, oxazole ring, benzoxazole ring, isoxazole ring, benzisoxazole ring, thiazole ring, benzothiazole ring, isothiazole ring, benzisothiazole ring, furan ring, benzofuran ring, or isobenzofuran ring; and

Ary 2 is a substituted or unsubstituted benzene ring, naphthyl ring, pyridine ring, pyrazine ring, pyrimidine ring, triazine ring, quinolone ring, isoquinoline ring, phthalazine ring, quinazoline ring, quinoxaline ring, thiophene ring, benzothiophene ring, pyrrole ring, indole ring, isoindole ring, pyrazole ring, indazole ring, imidazole ring, benzimidazole ring, triazole ring, benzotriazole ring, oxazole ring, benzoxazole ring, isoxazole ring, benzisoxazole ring, thiazole ring, benzothiazole ring, isothiazole ring, benzisothiazole ring, furan ring, benzofuran ring, or isobenzofuran ring.

4. The flow battery of claim 1 , wherein the active material is an unbound form of the bridged compound.

5. The flow battery of claim 1 , wherein the active material is the coordination compound comprising the bridged compound as at least one ligand.

6. The flow battery of claim 5 , wherein the coordination compound has a formula of

D g M(L 1 )(L 2 )(L 3 );

wherein

M is a transition metal;

D is ammonium, tetraalkylammonium, or an alkali metal ion; g ranges between 0 and 6; and

L 1 , L 2 and L 3 are ligands, at least one of L 1 , L 2 and L 3 being the bridged compound.

7. The flow battery of claim 6 , wherein the transition metal is Ti.

8. The flow battery of claim 6 , wherein at least one of L 1 , L 2 and L 3 is a catecholate ligand or a substituted catecholate ligand.

9. The flow battery of claim 1 , wherein the bridged compound has a structure of

wherein:

R 11 and R 12 are, independently, alkyl substituted with one or more of hydroxyl, carboxyl, amine, or sulfonyl; C 2 -C 6 polyol; OR 3 ; SR 3 ; S(═O)R 3 ; S(═O) 2 R 3 ; NR 9 R 10 ; CH 2 (OCH 2 CH 2 )—OCH 3 ; or C(═O)R 4 ; and

n is 0, 1, 2, or 3 and m is 1, 2, or 3.

10. The flow battery of claim 9 , wherein the active material is an unbound form of the bridged compound.

11. The flow battery of claim 9 , wherein the active material is the coordination compound comprising the bridged compound as at least one ligand.

12. The flow battery of claim 11 , wherein the coordination compound has a formula of:

D g M(L 1 )(L 2 )(L 3 );

wherein

M is a transition metal; D is ammonium, tetraalkylammonium, or an alkali metal ion;

g ranges between 0 and 6; and

L 1 , L 2 and L 3 are ligands, at least one of L 1 , L 2 and L 3 being the bridged compound.

13. The flow battery of claim 12 , wherein the transition metal is Ti.

14. The flow battery of claim 12 , wherein at least one of L 1 , L 2 and L 3 is a catecholate ligand or a substituted catecholate ligand.

15. The flow battery of claim 1 , wherein Z is S.

16. The flow battery of claim 1 , wherein Z is S(═O).

17. The flow battery of claim 1 , wherein Z is S(═O) 2 .

18. The flow battery of claim 1 , wherein Z is CR 1 R 2 .

19. The flow battery of claim 1 , wherein Z is O.