Symmetric Redox Molecules Using Synergistic Electron Directing Pairs

Patent metadata

Field	Value
Publication number	US-2024339644-A1
Application number	US-202418597482-A
Country	US
Kind code	A1
Filing date	Mar 6, 2024
Priority date	Mar 31, 2023
Publication date	Oct 10, 2024
Grant date	—

Abstract

Disclosed herein are a variety of systems, compositions, and methods for reversibly storing electrical energy in a symmetric redox flow battery with a unit cell potential equal to or greater than 3 volts. The systems include a conjugated organic molecule, a positive section, and a negative section. The conjugated organic molecule comprises a pair of electron-donating groups and a pair of electron-withdrawing groups, wherein a first electron-donating group of the electron donating groups is one ring position from a first electron-withdrawing group of the electron-withdrawing groups, and wherein a second electron-donating group is one ring position from a second electron-withdrawing group of the electron-withdrawing groups. The positive section includes a first metal electrode in contact with a catholyte comprising a portion of the conjugated organic molecule. The negative section comprises a second metal electrode in contact with an anolyte including an additional portion of the conjugated organic molecule.

First claim

What is claimed is:

1 . A system for energy storage comprising:
a conjugated organic molecule comprising a pair of electron-donating groups and a pair of electron-withdrawing groups, wherein a first electron-donating group of the electron donating groups is one ring position from a first electron-withdrawing group of the electron-withdrawing groups, and wherein a second electron-donating group is one ring position from a second electron-withdrawing group of the electron-withdrawing groups; a positive section comprising a first metal electrode in contact with a catholyte comprising a portion of the conjugated organic molecule and a supporting electrolyte dissolved in a solvent; and a negative section comprising a second metal electrode in contact with an anolyte comprising an additional portion of the conjugated organic molecule and additional electrolyte dissolved in additional solvent.

2 . The system of claim 1 , wherein the conjugated organic molecule has at least 2 electrochemically reversible redox states separated by at least 2 V.

3 . The system of claim 1 , wherein the conjugated organic molecule in a neutral state is aromatic with two or fewer conjugated rings.

4 . The system of claim 1 , wherein the conjugated organic molecule comprises a heterocyclic compound with two or fewer conjugated rings.

5 . The system of claim 4 , wherein the heterocyclic compound comprises a diazene with 1 or 2 rings.

6 . The system of claim 1 , wherein the conjugated organic molecule comprises a 2,3-dicyano-1,4-dialkylbenzene moiety.

7 . The system of claim 1 , wherein the conjugated organic molecule comprises a 1,4-dialkyl-1,4-dihydroquinoxaline-2,3-dione moiety.

8 . The system of claim 1 , wherein the conjugated organic molecule comprises N,N′-dialkyl phthalhydrazide.

9 . The system of claim 1 , wherein the conjugated organic molecule comprises dialkyl 2,5-dialkoxyterephthalate moiety.

10 . The system of claim 1 comprising from 2 to 200 electrochemical cells to form a battery stack, wherein each of the electrochemical cells comprises a corresponding positive section comprising the catholyte and a corresponding negative section comprising the anolyte.

11 . The system of claim 1 , wherein the solvent and additional solvent are each an aprotic solvent selected from the group consisting of acetonitrile, dimethyl sulfoxide, sulfolane, dimethylacetamide, dimethylformamide, propylene carbonate, ethylene carbonate propyl sulfone, and butyl sulfone.

12 . The system of claim 1 , wherein the positive section is separated from the negative section by a porous separator and/or an ion-selective membrane, and wherein the system further comprises a circulation device configured to circulate the catholyte or the anolyte from a storage tank to the positive section or the negative section.

13 . A composition comprising:
a multivalent redox-active organic molecule in a supporting electrolyte, wherein the multivalent redox active organic molecule comprises a pair of electron-donating groups and a pair of electron-withdrawing groups, wherein a first electron-donating group of the electron donating groups is one ring position from a first electron-withdrawing group, and wherein a second electron-donating group is one ring position from a second electron-withdrawing group.

14 . The composition of claim 13 :
wherein the pair of electron-donating groups is selected from the group consisting of alkoxy, dialkylamino, alkylamino, acyloxy, dialkylphosphino, and alkylthio groups; and wherein the pair of electron-withdrawing groups is selected from the group consisting of cyano, trifluoromethylsulfonyl, nitro, trihalomethyl, acyl, alkoxycarbonyl, and aminocarbonyl groups.

15 . The composition of claim 13 , wherein the multivalent redox-active organic molecule has a pair of diketone substituents, and wherein the pair of electron-donating groups is selected from the group consisting of alkoxy, dialkylamino, alkylamino, acyloxy, dialkylphosphino, and alkylthio groups.

16 . The composition of claim 13 , wherein the multivalent redox-active organic molecule is a diazene and, wherein the pair of electron-withdrawing groups is selected from the group consisting of alkoxy, dialkylamino, alkylamino, acyloxy, dialkylphosphino, and alkylthio groups.

17 . The composition of claim 13 , wherein the multivalent redox-active organic molecule is a conjugated N,N′-dialkylazene, and wherein the pair of electron-withdrawing groups is selected from the group consisting of ketone, cyano, trifluoromethylsulfonyl, nitro, trihalomethyl, acyl, alkoxycarbonyl and aminocarbonyl groups.

18 . A method for reversibly storing electrical energy in a symmetric redox flow battery with a unit cell potential equal to or greater than 3 volts, the method comprising:
flowing a catholyte into contact with a first metal electrode in a positive section of the redox flow battery, wherein the catholyte comprises a single species of a conjugated organic molecule dissolved in a solvent, wherein the conjugated organic molecule comprises a pair of electron-donating groups and a pair of electron-withdrawing groups, wherein a first electron-donating group of the electron donating groups is one ring position from a first electron-withdrawing group, and wherein a second electron-donating group is one ring position from a second electron-withdrawing group; flowing an anolyte into contact with a second metal electrode in a negative section of the redox flow battery, wherein the negative section is separated from the positive section with an ion-transporting membrane, wherein the anolyte comprises an additional portion of the organic molecule dissolved in additional solvent; and supplying electrical energy to the first metal electrode and the second metal electrode while an external load is not in electrical communication with the first metal electrode and the second metal electrode to charge the redox flow battery while flowing the catholyte and flowing the anolyte.

19 . The method of claim 18 , further comprising discharging the redox flow battery by establishing electrical communication between the external load with the first metal electrode and the second metal electrode while flowing the catholyte and flowing the anolyte.

20 . The method of claim 18 :
wherein the electron-donating group is selected from an electron-donating substituent pair selected from the group consisting of alkoxy, dialkylamino, alkylamino, acyloxy, dialkylphosphino and alkylthio groups; wherein the electron-withdrawing group is selected from the group consisting of cyano, trifluoromethylsulfonyl, nitro, trihalomethyl, acyl, alkoxycarbonyl, and aminocarbonyl groups; and wherein the conjugated organic molecule is selected from the group consisting of a substituted aromatic moiety with up to 2 aromatic rings, a heterocyclic diazene with up to 2 rings, a heterocylic tetrazine, and a heterocyclic quinonoid.

Assignees

• Exxonmobil Technology & Engineering Company

Inventors

• Desai Divyaraj
• Mabon Ross
• Metz Jordan N
• Bodige Satish
• Chambers Latoya S
• Saathoff Jonathan D

Classifications

• H01M8/24

  Grouping of fuel cells, e.g. stacking of fuel cells · CPC title

• H01M8/188 Primary

  by recharging of redox couples containing fluids; Redox flow type batteries · CPC title

• Y02E60/50

  Fuel cells · CPC title