# US 11,078,578 B2 · System and method for electrochemical separation of oxygen

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- Number: US 11,078,578 B2
- Document ID: US11078578B2
- Status: Granted
- Kind: B2
- Application number: 15/858,187
- Filed: 2018-01-25
- Published: 2019-07-25
- Granted: 2021-08-03
- Earliest claimed: 2018-01-25
- Assignees: Palo Alto Research Center Incorporated
- Applicants: Palo Alto Research Center Incorporated
- Inventors: Divyaraj Desai; Jessica Louis Baker Rivest
- Web page: https://patentgrep.com/patent/US11078578B2

## CPC

- C25B 1/02: Hydrogen or oxygen
- B01D 53/326: {in electrochemical cells}
- C25B 9/19: with diaphragms
- C25B 9/75: having bipolar electrodes
- C25B 9/77: having diaphragms
- C25B 13/02: characterised by shape or form
- C25B 13/08: based on organic materials
- H01M 8/0289: Means for holding the electrolyte (solid polymer electrolytes H01M8/1018)
- H01M 8/1041: Polymer electrolyte composites, mixtures or blends
- B01D 2256/12: Oxygen
- H01M 2300/0045: Room temperature molten salts comprising at least one organic ion
- H01M 2300/008: Halides
- Y02E 60/50: Fuel cells
- C25B: ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR (anodic or cathodic protection C23F13/00; single-crystal growth C30B)
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

A system comprises a first electrode, an electrolyte membrane, and a second electrode. The first electrode is configured to reduce oxygen in a gas to an oxygen carrier ion at an intermediate temperature. The electrolyte membrane is configured to transport the oxygen carrier ion, and the second electrode is configured to oxidize the oxygen carrier ion to an oxygen molecule. Oxidation of the oxygen molecule consumes less than four electrons.

## Claims

### Claim 1

A system, comprising:
a first electrode configured to reduce oxygen in a gas to an oxygen carrier ion at an intermediate temperature equal to or above 100° C. and equal to or less than 300° C.;
an electrolyte membrane configured to transport the oxygen carrier ion; and
a second electrode configured to receive the oxygen carrier ion and oxidize the oxygen carrier ion to an oxygen molecule, wherein oxidation of the oxygen molecule consumes less than four electrons.

### Claim 2 (depends on 1)

The system of claim 1, wherein the electrolyte membrane comprises a nanoporous support and at least one of a poly(electrolyte) and an ionic liquid.

### Claim 3 (depends on 2)

The system of claim 2, wherein the nanoporous support comprises at least one of polyimide, polycarbonate, polytetrafluoroethylene, perflouroelastomer, alumina, zirconia, and silica.

### Claim 4 (depends on 2)

The system of claim 2, wherein the ionic liquid comprises cations of at least one of piperidium, phosphonium, pyridinium, pyrrolidinium, and ammonium.

### Claim 5 (depends on 2)

The system of claim 2, wherein the ionic liquid comprises anions of at least one of trifluoromethanesulfonate, hexafluorophosphate, trifluoromethanesulfonylimide, superoxide, and peroxide.

### Claim 6 (depends on 1)

The system of claim 1, wherein the electrolyte membrane is configured to transport the oxygen carrier ion at a flux of at least 10 mol m−2 h−1.

### Claim 7 (depends on 1)

The system of claim 1, wherein the oxygen carrier ion is at least one of a superoxide, peroxide, and a nitrate ion.

### Claim 8 (depends on 1)

The system of claim 1, wherein the electrolyte membrane comprises a polymer membrane configured to transport a superoxide ion.

### Claim 9 (depends on 1)

The system of claim 1, wherein at least one of the first and second electrodes comprises a catalyst.

### Claim 10 (depends on 1)

The system of claim 1, wherein the electrolyte membrane has a thickness of less than about 250 μm.

### Claim 11 (depends on 1)

The system of claim 1, further comprising an output oxygen stream coupled to the second electrode, wherein a ratio of partial pressure of oxygen in the output stream to partial pressure of oxygen in the gas is greater than 1.

### Claim 12 (depends on 1)

The system of claim 1, further comprising an output oxygen stream coupled to the second electrode, wherein the output oxygen stream has a higher pressure than the gas.

### Claim 13 (depends on 1)

The system of claim 1, further comprising an output oxygen stream coupled to the second electrode, wherein the output oxygen stream has a partial pressure lower than about 0.05 bar.

### Claim 14 (depends on 1)

An apparatus comprising:
a first system according to claim 1; and
a second system according to claim 1.

### Claim 15 (depends on 14)

The apparatus of claim 14, wherein the first and second systems are connected in parallel.

### Claim 16 (depends on 14)

The apparatus of claim 14, wherein the first and second systems are connected in series.

### Claim 17

A method comprising:
receiving an input gas comprising oxygen;
contacting the gas with a first electrode of an electrochemical cell to reduce the oxygen to an oxygen carrier ion;
transporting the oxygen carrier ion across the cell through an electrolyte membrane;
oxidizing the oxygen carrier ion to form an oxygen molecule at a second electrode of the electrochemical cell; and
discharging an output oxygen gas,
wherein the method is performed at an intermediate temperature, equal to or above 100° C. and equal to or less than 300° C., and consumes less than four electrons per oxygen molecule.

### Claim 18 (depends on 17)

The method of claim 17, wherein the pressure of the input gas is greater than the pressure of the output oxygen gas.

### Claim 19 (depends on 17)

The method of claim 17, wherein the pressure of the output oxygen gas is greater than the pressure of the input gas.