Flow batteries having an electrode with differing hydrophilicity on opposing faces and methods for production and use thereof

Patent metadata

Field	Value
Publication number	US-2018108916-A1
Application number	US-201615297071-A
Country	US
Kind code	A1
Filing date	Oct 18, 2016
Priority date	Oct 18, 2016
Publication date	Apr 19, 2018
Grant date	—

Abstract

Electrochemical cells, such as those present within flow batteries, can include at least one electrode with one face being more hydrophilic than is the other. Such electrodes can lessen the incidence of parasitic reactions by directing convective electrolyte circulation toward a separator in the electrochemical cell. Flow batteries containing the electrochemical cells can include: a first half-cell containing a first electrode with a first face and a second face that are directionally opposite one another, a second half-cell containing a second electrode with a first face and a second face that are directionally opposite one another, and a separator disposed between the first half-cell and the second half-cell. The first face of both the first and second electrodes is disposed adjacent to the separator. The first face of at least one of the first electrode and the second electrode is more hydrophilic than is the second face.

First claim

What is claimed is the following:

1 . A flow battery comprising:
a first half-cell containing a first electrode with a first face and a second face that are directionally opposite one another; a second half-cell containing a second electrode with a first face and a second face that are directionally opposite one another; and a separator disposed between the first half-cell and the second half-cell;
wherein the first face of both the first and second electrodes is disposed adjacent to the separator, and the first face of at least one of the first electrode and the second electrode is more hydrophilic than is the second face.

2 . The flow battery of claim 1 , wherein at least one of the first electrode and the second electrode has a hydrophilicity gradient decreasing outwardly from the separator.

3 . The flow battery of claim 2 , wherein the hydrophilicity gradient is a stepped gradient.

4 . The flow battery of claim 1 , wherein at least one of the first electrode and the second electrode further comprises a conductive additive deposited upon the second face to a greater extent than upon the first face.

5 . The flow battery of claim 1 , wherein at least one of the first electrode and the second electrode comprises a carbon electrode.

6 . The flow battery of claim 5 , wherein at least one of the first electrode and the second electrode comprises a first carbon cloth and a second carbon cloth that are layered together such that the first carbon cloth is adjacent to the separator, and the first carbon cloth is more hydrophilic than is the second carbon cloth.

7 . The flow battery of claim 5 , wherein the carbon electrode is plasma functionalized upon the first face to a greater extent than upon the second face, thereby rendering the first face more hydrophilic.

8 . The flow battery of claim 5 , wherein the carbon electrode is functionalized upon the second face with a plurality of hydrophobic molecules to a greater extent than upon the first face, thereby rendering the first face more hydrophilic.

9 . The flow battery of claim 5 , wherein the carbon electrode is functionalized upon the first face with a plurality of hydrophilic molecules to a greater extent than upon the second face, thereby rendering the first face more hydrophilic.

10 . The flow battery of claim 1 , wherein the first face of both the first and second electrodes is more hydrophilic than is the second face.

11 . The flow battery of claim 1 , further comprising:
a first bipolar plate contacting the second face of the first electrode and a second bipolar plate contacting the second face of the second electrode.

12 . The flow battery of claim 11 , wherein the first bipolar plate and the second bipolar plate each contain a plurality of flow channels, the plurality of flow channels being configured to deliver a first electrolyte solution to the first electrode and a second electrolyte solution to the second electrode.

13 . A method comprising:
providing a conductive material with a first face and a second face that are directionally opposite one another, the first face being more hydrophilic than is the second face; and forming an electrochemical cell comprising:
a first half-cell containing a first electrode;
a second half-cell containing a second electrode; and
a separator disposed between the first half-cell and the second half-cell;
wherein at least one of the first electrode and the second electrode comprises the conductive material, and the first face of the conductive material is disposed adjacent to the separator.

14 . The method of claim 13 , wherein the conductive material comprises a carbon cloth.

15 . The method of claim 14 , further comprising:
functionalizing the first face of the conductive material to a greater extent than the second face, thereby rendering the first face more hydrophilic.

16 . The method of claim 15 , wherein the conductive material is plasma functionalized upon the first face to a greater extent than upon the second face, thereby rendering the first face more hydrophilic.

17 . The method of claim 15 , wherein the conductive material is functionalized upon the first face to a greater extent than upon the second face with a plurality of hydrophilic molecules, thereby rendering the first face more hydrophilic.

18 . The method of claim 14 , further comprising:
functionalizing the second face of the conductive material to a greater extent than the first face with a plurality of hydrophobic molecules, thereby rendering the first face more hydrophilic.

19 . The method of claim 14 , wherein the conductive material comprises a first carbon cloth and a second carbon cloth that are layered together such that the first carbon cloth is adjacent to the separator, and the first carbon cloth is more hydrophilic than is the second carbon cloth.

20 . The method of claim 13 , wherein the electrochemical cell is located within a flow battery.

21 . The method of claim 13 , wherein a first bipolar plate contacts the first electrode opposite the separator and a second bipolar plate contacts the second electrode opposite the separator.

22 . The method of claim 21 , further comprising:
connecting a plurality of the electrochemical cells in series with one another in an electrochemical stack.

23 . A method comprising:
providing a flow battery having an electrochemical cell comprising:
a first half-cell containing a first electrode with a first face and a second face that are directionally opposite one another;
a second half-cell containing a second electrode with a first face and a second face that are directionally opposite one another; and
a separator disposed between the first half-cell and the second half-cell;
wherein the first face of both the first and second electrodes is disposed adjacent to the separator, and the first face of at least one of the first electrode and the second electrode is more hydrophilic than is the second face; and

circulating a first electrolyte solution through the first half-cell and a second electrolyte solution through the second half-cell;
wherein convective flow of at least one of the first electrolyte solution and the second electrolyte solution occurs preferentially in a hydrophilic region of the first electrode or the second electrode proximate the separator.

24 . The method of claim 23 , wherein a first bipolar plate contacts the second face of the first electrode and a second bipolar plate contacts the second face of the second electrode, and the first electrolyte solution and the second electrolyte solution are supplied through a plurality of flow channels within the first bipolar plate and the second bipolar plate, respectively.

25 . The method of claim 23 , wherein the first face of both the first and second electrodes is more hydrophilic than is the second face.

Assignees

• Lockheed Martin Advanced Energy Storage Llc

Inventors

• Loretz Jeremy
• Puranam Srivatsava Venkataranga
• Vanbenschoten Helen Elizabeth

Classifications

• H01M4/8605

  Porous electrodes · CPC title

• H01M4/8636 Primary

  with a gradient in another property than porosity (H01M4/861 takes precedence) · CPC title

• H01M4/8657

  layered · CPC title

• H01M4/96

  Carbon-based electrodes · CPC title

• H01M4/8642 Primary

  Gradient in composition · CPC title