# US 10,873,101 B2 · Flow battery

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- Number: US 10,873,101 B2
- Document ID: US10873101B2
- Status: Granted
- Kind: B2
- Application number: 15/713,715
- Filed: 2017-09-25
- Published: 2018-04-05
- Granted: 2020-12-22
- Earliest claimed: 2016-10-04
- Assignees: Panasonic Intellectual Property Management Co., Ltd.
- Applicants: Panasonic Intellectual Property Management Co., Ltd.
- Inventors: Honami Nariyama; Yu Otsuka
- Web page: https://patentgrep.com/patent/US10873101B2

## CPC

- H01M 8/188: {by recharging of redox couples containing fluids; Redox flow type batteries}
- H01M 4/86: Inert electrodes with catalytic activity, e.g. for fuel cells
- C07D 339/06: having the hetero atoms in positions 1 and 3, e.g. cyclic dithiocarbonates
- Y02E 60/50: Fuel cells
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- C07D: HETEROCYCLIC COMPOUNDS (macromolecular compounds C08)
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

A flow battery includes a first liquid containing a first electrode mediator dissolved therein, a first electrode immersed in the first liquid, a first active material immersed in the first liquid, and a first circulation mechanism that circulates the first liquid between the first electrode and the first active material, wherein the first electrode mediator includes a tetrathiafulvalene derivative, and the tetrathiafulvalene derivative has a chain-forming substituent at positions 4,4′ and 5,5′ of a tetrathiafulvalene skeleton thereof.

## Claims

### Claim 1

A flow battery comprising:
a first liquid containing a first electrode mediator dissolved therein;
a first electrode immersed in the first liquid;
a first active material immersed in the first liquid; and
a first circulation mechanism that circulates the first liquid between the first electrode and the first active material,
wherein the first electrode mediator includes a tetrathiafulvalene derivative, and
the tetrathiafulvalene derivative has a chain-forming substituent at positions 4,4′ and 5,5′ of a tetrathiafulvalene skeleton thereof, and
wherein the first active material is insoluble in the first liquid.

### Claim 2 (depends on 1)

The flow battery according to claim 1, wherein the tetrathiafulvalene derivative is represented by the following general formula (1),
wherein X denotes an oxygen atom, a sulfur atom, a nitrogen atom, a selenium atom, or a tellurium atom, and R1, R2, R3, and R4 independently denote at least one selected from the group consisting of chain saturated hydrocarbons, chain unsaturated hydrocarbons, cyclic saturated hydrocarbons, cyclic unsaturated hydrocarbons, a phenyl group, a hydrogen atom, a hydroxy group, a cyano group, an amino group, a nitro group, and a nitroso group.

### Claim 3 (depends on 2)

The flow battery according to claim 2, wherein at least one electron-withdrawing group selected from the group consisting of a sulfur atom, a nitrogen atom, and an oxygen atom is disposed at position X.

### Claim 4 (depends on 2)

The flow battery according to claim 2, wherein a linear substituent is disposed at positions R1, R2, R3, and R4.

### Claim 5 (depends on 2)

The flow battery according to claim 2, wherein a substituent at positions R1, R2, R3, and R4 is CnH2n+1 (n is an integer of 1≤n≤4).

### Claim 6 (depends on 2)

The flow battery according to claim 2, wherein a substituent at positions R1, R2, R3, and R4 is a branched substituent.

### Claim 7 (depends on 2)

The flow battery according to claim 2, wherein a substituent at positions R1, R2, R3, and R4 includes at least one element selected from the group consisting of boron, nitrogen, oxygen, fluorine, silicon, phosphorus, sulfur, chlorine, bromine, and iodine.

### Claim 8 (depends on 2)

The flow battery according to claim 2, wherein the tetrathiafulvalene derivative is at least one selected from the group consisting of tetrakis(dimethylthio)tetrathiafulvalene and tetrakis(diethylthio)tetrathiafulvalene.

### Claim 9 (depends on 1)

The flow battery according to claim 1, wherein
the tetrathiafulvalene derivative has a first oxidation-reduction potential and a second oxidation-reduction potential, and
the first active material has an equilibrium potential higher than the first oxidation-reduction potential and lower than the second oxidation-reduction potential.

### Claim 10 (depends on 1)

The flow battery according to claim 1, wherein
the first circulation mechanism includes a first container,
the first container contains the first active material and the first liquid,
the first circulation mechanism circulates the first liquid between the first electrode and the first container, and
contact between the first active material and the first liquid in the first container causes at least one of an oxidation reaction and a reduction reaction between the first active material and the first electrode mediator.

### Claim 11 (depends on 10)

The flow battery according to claim 10, wherein
the first circulation mechanism includes a first transfer prevention unit that prevents transfer of the first active material, and
the first transfer prevention unit is disposed on a path through which the first liquid flows from the first container to the first electrode.

### Claim 12 (depends on 1)

The flow battery according to claim 1, further comprising:
a second liquid containing a charge mediator and a discharge mediator dissolved therein;
a second electrode immersed in the second liquid;
a second active material immersed in the second liquid; and
a separating unit that separates the first electrode and the first liquid from the second electrode and the second liquid,
wherein the charge mediator has a lower equilibrium potential than the second active material, and
the discharge mediator has a higher equilibrium potential than the second active material.

### Claim 13 (depends on 12)

The flow battery according to claim 12, wherein
the second liquid contains lithium dissolved therein,
the second active material adsorbs and desorbs the lithium,
when charging, the charge mediator is reduced on the second electrode, the charge mediator reduced on the second electrode is oxidized by the second active material, and the second active material adsorbs the lithium, and
when discharging, the second active material on which the lithium is adsorbed reduces the discharge mediator, the second active material desorbs the lithium, and the discharge mediator reduced by the second active material is oxidized on the second electrode.

### Claim 14 (depends on 13)

The flow battery according to claim 13, wherein
when the charging, the discharge mediator is reduced on the second electrode, and
when the discharging, the charge mediator is oxidized on the second electrode.

### Claim 15 (depends on 12)

The flow battery according to claim 12, wherein
the charge mediator and the discharge mediator are condensed aromatic compounds, and
the second liquid containing the condensed aromatic compounds dissolved therein causes a solvated electron of lithium to be released and thereby dissolves the lithium as a cation.

### Claim 16 (depends on 15)

The flow battery according to claim 15, wherein the charge mediator is at least one selected from the group consisting of phenanthrene, biphenyl, O-terphenyl, triphenylene, and anthracene.

### Claim 17 (depends on 15)

The flow battery according to claim 15, wherein the discharge mediator is at least one selected from the group consisting of phenanthroline, 2,2′-bipyridyl, benzophenone, trans-stilbene, 4,4′-bipyridyl, 3,3′-bipyridyl, 2,4′-bipyridyl, 2,3′-bipyridyl, cis-stilbene, acetophenone, propiophenone, butyrophenone, valerophenone, and ethylenediamine.

### Claim 18 (depends on 12)

The flow battery according to claim 12, further comprising:
a second circulation mechanism including a second container,
wherein the second active material and the second liquid are contained in the second container,
the second circulation mechanism circulates the second liquid between the second electrode and the second container, and
contact between the second active material and the second liquid in the second container causes at least one of an oxidation reaction of the charge mediator with the second active material and a reduction reaction of the discharge mediator with the second active material.

### Claim 19 (depends on 18)

The flow battery according to claim 18, wherein
the second circulation mechanism includes a second transfer prevention unit that prevents transfer of the second active material, and
the second transfer prevention unit is disposed on a path through which the second liquid flows from the second container to the second electrode.

### Claim 20 (depends on 1)

The flow battery according to claim 1, wherein the first active material is lithium-containing transition metal compound.

### Claim 21 (depends on 1)

The flow battery according to claim 1, wherein the first active material is a metal oxide represented by LixMyO2, M denotes at least one selected from the group consisting of Ni, Mn, and Co, and x and y each are any number.

### Claim 22 (depends on 1)

The flow battery according to claim 1, wherein the first active material is at least one selected from the group consisting of LiFePO4, LiMnO2, LiMn2O4, and LiCoO2.