Electrochemical conversion of halogenated compounds and associated systems

Patent metadata

Field	Value
Publication number	US-12009499-B2
Application number	US-202217969486-A
Country	US
Kind code	B2
Filing date	Oct 19, 2022
Priority date	Oct 3, 2016
Publication date	Jun 11, 2024
Grant date	Jun 11, 2024

Abstract

Methods and systems for the electrochemical conversion of halogenated compounds are provided. In some embodiments, a method comprises converting a halogenated compound (e.g., fluorinated gas) to relatively non-hazardous products via one or more electrochemical reactions. The electrochemical reaction(s) may occur under relatively mild conditions (e.g., low temperature) and/or without the aid of a catalyst. In some embodiments, the electrochemical reaction may produce a relatively large amount of energy. In some such cases, systems, described herein, may be designed to facilitate the conversion of the halogenated compound (e.g., SF 6 , NF 3 ) while harnessing (e.g., storing, converting) the energy associated with the electrochemical reaction. System and methods described herein may be used in a wide variety of applications, including waste management (e.g., environmental remediation, greenhouse gas mitigation), energy recovery (e.g., industrial energy recovery), and primary batteries (e.g., metal-gas batteries).

First claim

What is claimed is:

1. A method, comprising:
in a sealed electrochemical cell, reacting a halogenated compound with a metal to form a metal halide, wherein the halogenated compound is a gas at standard temperature and pressure and the metal has a standard reduction potential of less than or equal to about −1.4 V vs. a standard hydrogen electrode.

2. The method of claim 1 , comprising reacting the halogenated compound with the metal in an electrolyte to form the metal halide.

3. The method of claim 2 , wherein the electrolyte comprises a non-aqueous solvent.

4. The method of claim 2 , wherein the electrolyte comprises an organic solvent.

5. The method of claim 1 , wherein the reacting step occurs at a temperature of less than or equal to about 60° C.

6. The method of claim 1 , wherein the reacting step occurs at a pressure of greater than or equal to about 1 atm.

7. The method of claim 1 , wherein the reacting step occurs at a cathode.

8. The method of claim 7 , wherein the cathode comprises carbon, a noble metal, a transition metal, a metal oxide, or a metal fluoride.

9. The method of claim 7 , wherein the cathode comprises carbon nanotubes, graphene, and/or carbon nanofibers.

10. The method of claim 1 , wherein the halogenated compound is reduced during the reacting step.

11. The method of claim 1 , further comprising forming a second reaction product as a result of the reacting step.

12. The method of claim 1 , wherein the metal is selected from the group consisting of alkali metals and alkaline earth metals.

13. The method of claim 1 , wherein the metal is lithium or sodium.

14. The method of claim 1 , wherein the electrochemical cell is a galvanic cell.

15. The method of claim 1 , wherein the halogenated compound is a fluorinated compound.

16. The method of claim 1 , wherein the halogenated compound is selected from the group consisting of sulfur hexafluoride, nitrogen trifluoride, and perfluorinated fluorocarbons.

17. The method of claim 1 , wherein the metal halide is a metal fluoride.

18. The method of claim 1 , wherein the sealed electrochemical cell comprises an anode, and wherein the anode comprises a metal selected from the group consisting of alkali metals and alkaline earth metals.

19. The method of claim 18 , wherein the anode comprises lithium or sodium.

20. The method of claim 1 , further comprising maintaining a concentration of the gas in a headspace of the sealed electrochemical cell that allows the gas to be transported from the headspace to an electrolyte of the sealed electrochemical cell prior to, during, and/or after use of the sealed electrochemical cell.

21. A method, comprising:
at an electrified interface of a cathode, electrochemically reacting a halogenated compound with a metal ion to form a metal halide, wherein the halogenated compound is a gas at standard temperature and pressure and the metal ion has a standard reduction potential of less than or equal to about −1.4 V vs. a standard hydrogen electrode.

22. The method of claim 21 , wherein the metal ion is a lithium cation and/or a sodium cation.

23. The method of claim 21 , wherein the cathode comprises carbon, a noble metal, a transition metal, a metal oxide, or a metal fluoride.

24. The method of claim 21 , wherein the electrified interface of the cathode is an electrified interface between the cathode and an electrolyte.

25. The method of claim 24 , wherein the halogenated compound is dissolved in the electrolyte.

Assignees

• Massachusetts Inst Technology

Inventors

• Gallant Betar
• Li Yuanda
• Khurram Aliza
• He Mingfu

Classifications

• H01M4/46

  Alloys based on magnesium or aluminium · CPC title

• H01M4/40

  Alloys based on alkali metals · CPC title

• H01M6/14 Primary

  Cells with non-aqueous electrolyte · CPC title

• H01M12/04

  composed of a half-cell of the fuel-cell type and of a half-cell of the primary-cell type · CPC title

• H01M4/8605

  Porous electrodes · CPC title