Stable bromine charge storage in porous carbon electrodes using tetraalkylammonium bromides for reversible solidcomplexation

Patent metadata

Field	Value
Publication number	US-2017256366-A1
Application number	US-201715601811-A
Country	US
Kind code	A1
Filing date	May 22, 2017
Priority date	Apr 21, 2014
Publication date	Sep 7, 2017
Grant date	—

Abstract

Electrolytes for use in electric double-layer capacitors (EDLCs; often referred as supercapacitors or ultracapacitors) are disclosed. In one example, the electrolyte comprises viologen in both the anolyte and the catholyte (with bromide). In another example, the electrolyte comprises viologen (in the anolyte) and tetraalkylammonium with bromide (in the catholyte), wherein the tetraalkylammonium is used to achieve solid complexation of bromine in the activated carbon of the cathode. In a third example, a zinc bromine/tetraalkylammonium supercapacitor/battery hybrid is disclosed. Also disclosed is a corrosion resistant bipolar pouch cell that can be used with the electrolyte embodiments described herein.

First claim

What is claimed is:

1 . An energy storage device, comprising:
an electrical double layer capacitor (EDLC) including two electrodes in contact with an electrolyte having an integral active component for storing a charge, the electrolyte including a first redox couple comprising a halide and a second redox couple comprising a viologen, wherein: during charging, the electrolyte evolves into a catholyte including the first redox couple and an anolyte including the second redox couple; and when charged, the charge is stored in Faradaic reactions with the first and second redox couples in the electrolyte and in a double-layer capacitance of a porous carbon material that comprises at least one of the electrodes.

2 . The device of claim 1 , wherein the halide comprises bromine.

3 . The device of claim 2 , wherein the viologen has the structure:

and
R is an alkyl.

4 . The device of claim 3 , wherein viologen comprises at least one compound selected from ethyl viologen, butyl viologen, and pentyl viologen.

5 . The device of claim 2 , wherein the electrolyte further comprises a complexing agent comprising a tetraalkylammonium that forms a complex with the bromine moeity in the catholyte.

6 . The device of claim 5 , wherein the tetraalkylammonium is tetrabutylammonium bromide.

7 . The device of claim 5 , wherein:
the tetrabutylammonium bromide combines with the bromine moeity to form a [TBA + .Br 3 − ] solid complex retained in the pores of the porous carbon material of the electrode comprising a cathode.

8 . The device of claim 1 , wherein the catholyte further comprises a viologen.

9 . The device of claim 1 , wherein the electrolyte further comprises a complexing agent comprising a viologen that forms a complex with the halide comprising a bromine moeity in the catholyte.

10 . The device of claim 9 , wherein the viologen is at least one compound selected from hexyl viologen and pentyl viologen.

11 . The device of claim 9 , wherein the viologen forming a complex with the bromine moeity has the structure:

and
R is an alkyl having at least 4 carbons.

12 . An energy storage device, comprising:
a cathode and an anode in contact with an electrolyte including zinc halide; the cathode including carbon; and tetraalkylammonium complexing agent on the cathode, wherein: during charging, the zinc moiety from the zinc halide plates onto the anode and the halogen in the halide oxidizes so as to form a solid complex with the tetraalkylammonium on the cathode.

13 . The energy storage device of claim 12 , wherein the carbon in the cathode is soaked with the tetraalkylammonium complexing agent and the tetraalkylammonium complexing agent is tetrabutylammonium bromide or cetyltrimethylammonium bromide.

14 . The energy storage device of claim 12 , wherein the electrolyte does not include a viologen.

15 . An energy storage device, comprising:
one or more cells, each cell including: a pouch having a first wall and a second wall, the first wall and the second wall each comprising a current collector including a carbon-polymer composite; a plastic spacer, first and second electrodes, an electrolyte, and a separator inside the pouch; a seal between the first wall and the second wall so that the plastic spacer, the second electrode, the electrolyte, and the separator are sealed inside the pouch.

16 . The device of claim 15 , wherein the seal is a heat seal and the carbon-polymer composite is a thermoplastic.

17 . The device of claim 16 , wherein the separator and the spacer are made from one component with a microporous polymer separator that has porosity collapse in the region of the heat-seal.

18 . The device of claim 15 , wherein the first and second walls are flexible and each have a thickness of 100 micrometers or less.

19 . The device of claim 15 , further comprising a compartment housing the electrodes, the separator, and the electrolyte permeating the electrodes and separator, wherein the compartment is bound above and below by the walls and on the edges by the inside of the plastic spacer.

20 . The device of claim 15 , comprising a plurality of the cells stacked on top of one another in a series configuration, wherein the positive current collector of one cell and the negative current collector of the adjacent cell are replaced by a single bipolar current collector made of the carbon-polymer composite.

21 . The device of claim 15 , wherein the device comprises an electrical double layer capacitor (EDLC) including the first and the second electrodes in contact with the electrolyte.

22 . The device of claim 21 , wherein:
the electrolyte includes a first redox couple comprising bromine or a bromine moeity and a second redox couple comprising a viologen; during charging, the electrolyte evolves into a catholyte including the first redox couple and an anolyte including the second redox couple; and when charged, the charge is stored in Faradaic reactions with the first and second redox couples in the electrolyte and in a double-layer capacitance of the porous carbon material that comprises at least one of the electrodes.

23 . The device of claim 22 , wherein the electrolyte couple further comprises a complexing agent comprising a tetraalkylammonium that forms a complex with the bromine or the bromine moeity in the catholyte.

24 . The device of claim 22 , wherein the electrolyte further comprises a complexing agent comprising a viologen that forms a complex with the bromine or the bromine moeity in the catholyte.

25 . The device of claim 15 , wherein:
the electrolyte includes zinc halide, the electrodes comprise a cathode and an anode, the cathode comprising carbon, tetraalkylammonium complexing agent is pre-soaked on the carbon in the cathode, and during charging, the zinc from the zinc halide plates onto the anode and the halogen in the halide oxidizes so as to form a solid complex with the tetraalkylammonium on the cathode.

Assignees

• Univ California

Inventors

• Stucky Galen D
• Evanko Brian
• Yoo Seung Joon
• Lipton Jason
• Boettcher Shannon W
• Ji David Xiulei
• Wang Xingfeng

Classifications

• H01G11/62 Primary

  characterised by the solute, e.g. salts, anions or cations therein · CPC title

• H01G9/016

  Electricity · mapped topic

• H01G9/10

  Sealing, e.g. of lead-in wires · CPC title

• C08K5/19

  Quaternary ammonium compounds · CPC title

• H01G11/70

  characterised by their structure · CPC title