Method for preparing cathode electrolyte for redox flow batteries, and redox flow battery

Patent metadata

Field	Value
Publication number	US-9972859-B2
Application number	US-201515309843-A
Country	US
Kind code	B2
Filing date	May 20, 2015
Priority date	May 26, 2014
Publication date	May 15, 2018
Grant date	May 15, 2018

Abstract

The present disclosure relate to a method for preparing a cathode electrolyte for redox flow batteries including the steps of: forming a first cathode electrolyte by reducing vanadium pentoxide (V 2 O 5 ) in an acidic solution in the presence of a specific reducing compound; forming a second cathode electrolyte by reducing vanadium pentoxide (V 2 O 5 ) in an acidic solution in the presence of a linear or branched aliphatic alcohol having 2 to 10 carbon atoms; and mixing the first cathode electrolyte and the second cathode electrolyte, and to a redox flow battery including the cathode electrolyte obtained by the preparation method.

First claim

The invention claimed is:

1. A method for preparing a cathode electrolyte for redox flow batteries comprising the steps of: forming a first cathode electrolyte by reducing vanadium pentoxide (V 2 O 5 ) in an acidic solution in the presence of at least one reducing compound selected from the group consisting of dicarboxylic acid containing a linear or branched alkylene group having 0 to 6 carbon atoms, hydrazine, and L-ascorbic acid;
forming a second cathode electrolyte by reducing vanadium pentoxide (V 2 O 5 ) in an acidic solution in the presence of a linear or branched aliphatic alcohol having 2 to 10 carbon atoms; and
mixing the first cathode electrolyte and the second cathode electrolyte.

2. The method for preparing a cathode electrolyte for redox flow batteries according to claim 1 ,
wherein the first cathode electrolyte and the second cathode electrolyte are mixed in a volume ratio of 12:1 to 1:1.

3. The method for preparing a cathode electrolyte for redox flow batteries according to claim 1 ,
wherein a concentration of the acidic solution in the first cathode electrolyte and the second cathode electrolyte is 0.1 M to 6 M.

4. The method for preparing a cathode electrolyte for redox flow batteries according to claim 1 ,
wherein the acidic solutions in the first cathode electrolyte and the second cathode electrolyte contain sulfuric acid, respectively.

5. The method for preparing a cathode electrolyte for redox flow batteries according to claim 1 ,
wherein a concentration of the vanadium pentoxide in the first cathode electrolyte and the second cathode electrolyte is 0.3 M to 3 M, respectively.

6. The method for preparing a cathode electrolyte for redox flow batteries according to claim 1 ,
wherein a concentration of the reducing compound in the first cathode electrolyte is 0.3 M to 3 M,
and a concentration of the aliphatic alcohol in the second cathode electrolyte is 0.3 M to 3 M.

7. The method for preparing a cathode electrolyte for redox flow batteries according to claim 1 ,
wherein a ratio of the concentration of the reducing compound relative to the concentration of vanadium pentoxide in the first cathode electrolyte is 0.8 to 1.2.

8. The method for preparing a cathode electrolyte for redox flow batteries according to claim 1 ,
wherein a ratio of the concentration of the aliphatic alcohol relative to the concentration of vanadium pentoxide in the second cathode electrolyte is 0.8 to 1.2.

9. A redox flow battery, comprising:
a cathode electrolyte for redox flow batteries prepared by the method of claim 1 ;
metal ions containing a V 2+ /V 3+ redox couple; and
an anode electrolyte containing a sulfuric acid solution.

10. The redox flow battery according to claim 9 , wherein the redox flow battery includes at least one unit cell, the unit cell comprising:
a separation membrane through which ions pass;
a pair of electrodes opposite to the center of the separation membrane; and
the cathode electrolyte and anode electrolyte which are present respectively in a cathode cell and an anode cell partitioned by the separation membrane.

11. The redox flow battery according to claim 9 ,
wherein the unit cell further includes a pair of flow frames attached to face each other on respective sides of the separation membrane.

12. The redox flow battery according to claim 9 ,
wherein the unit cell further includes a cell frame formed on the outer surface of the electrodes.

13. The redox flow battery according to claim 9 , further comprising:
a cathode electrolyte tank for storing the cathode electrolyte;
a cathode electrolyte pump for circulating the cathode electrolyte from the cathode electrolyte tank to the cathode cell of the unit cell during charge and discharge;
an anode electrolyte tank for storing the anode electrolyte; and
an anode electrolyte pump for circulating the anode electrolyte from the anode electrolyte tank to the anode cell of the unit cell during charge and discharge.

Assignees

• Lotte Chemical Corp

Inventors

• Kim Mi-Kyoung
• Choi Eun-Mi
• Kim Dae-Sik
• Jang Wooin
• Kang Taehyuk

Classifications

• H01M8/04276

  Arrangements for managing the electrolyte stream, e.g. heat exchange · CPC title

• H01M8/04283

  Supply means of electrolyte to or in matrix-fuel cells · CPC title

• H01M8/0273

  with sealing or supporting means in the form of a frame · CPC title

• H01M8/0289

  Means for holding the electrolyte (solid polymer electrolytes H01M8/1018) · CPC title

• H01M2300/0011

  Sulfuric acid-based · CPC title