# US 12,111,283 B2 · Gas sensor element and gas sensor

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- Number: US 12,111,283 B2
- Document ID: US12111283B2
- Status: Granted
- Kind: B2
- Application number: 16/813,995
- Filed: 2020-03-10
- Published: 2020-07-02
- Granted: 2024-10-08
- Earliest claimed: 2017-09-15
- Assignees: Denso Corporation
- Applicants: Denso Corporation
- Inventors: Masatoshi Ikeda; Shota Hagino; Chika Namekata
- Web page: https://patentgrep.com/patent/US12111283B2

## CPC

- G01N 27/4075: {Composition or fabrication of the electrodes and coatings thereon, e.g. catalysts}
- G01N 27/409: Oxygen concentration cells
- G01N 27/4071: {using sensor elements of laminated structure}
- G01N 27/4073: {Composition or fabrication of the solid electrolyte}
- G01N 27/4076: {Reference electrodes or reference mixtures}
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)

## Abstract

A gas sensor element includes a solid electrolyte body having oxygen ion conductivity, a measurement electrode provided on one surface of the solid electrolyte body and exposed to a measurement gas, and a reference electrode provided on the other surface of the solid electrolyte body and exposed to a reference gas. Both the measurement electrode and the reference electrode include noble metal particles, solid electrolyte particles having oxygen ion conductivity, and pores. The measurement electrode comprises a surface measurement electrode layer comprising a surface serving as a contact surface with the measurement gas and an intermediate measurement electrode layer disposed in contact with a surface at solid electrolyte body side of the surface measurement electrode layer. The surface measurement electrode layer has a higher porosity than the intermediate measurement electrode layer has. The gas sensor comprises the gas sensor element.

## Claims

### Claim 1

A gas sensor element comprising:
a solid electrolyte body having oxygen ion conductivity, a measurement electrode provided on a first surface of the solid electrolyte body and exposed to a measurement gas, and a reference electrode provided on a second surface of the solid electrolyte body that is opposite to the first surface and exposed to a reference gas, wherein
both the measurement electrode and the reference electrode comprise noble metal particles, solid electrolyte particles having oxygen ion conductivity, and pores, and
the measurement electrode comprises:
a surface measurement electrode layer comprising a surface serving as a contact surface with the measurement gas and an intermediate measurement electrode layer comprising a plurality of layers, one layer of the intermediate measurement electrode layer being disposed in contact with a surface at a solid electrolyte body side of the surface measurement electrode layer, and
the surface measurement electrode layer has a higher porosity than porosity of each of the plurality of layers of the intermediate measurement electrode layer, and
each of the plurality of layers included in the intermediate measurement electrode layer have a porosity increasing from the solid electrolyte body toward the surface measurement electrode layer.

### Claim 2 (depends on 1)

The gas sensor element according to claim 1, wherein
the surface measurement electrode layer has a porosity of 15% or more and 30% or less.

### Claim 3 (depends on 1)

The gas sensor element according to claim 1, wherein
each of layers of the intermediate measurement electrode layer has a porosity of 15% or less.

### Claim 4 (depends on 1)

The gas sensor element according to claim 1, wherein
the reference electrode comprises:
a surface measurement electrode layer comprising a surface serving as a contact surface with the reference gas and an intermediate measurement electrode layer disposed in contact with a surface at a solid electrolyte body side of the surface measurement electrode layer of the reference electrode, and
the surface measurement electrode layer of the reference electrode has a higher porosity than the intermediate measurement electrode layer of the reference electrode.

### Claim 5 (depends on 4)

The gas sensor element according to claim 4, wherein
the surface measurement electrode layer of the reference electrode has a porosity of 15% or more and 30% or less.

### Claim 6 (depends on 4)

The gas sensor element according to claim 4, wherein
the intermediate measurement electrode layer of the reference electrode has a porosity of 15% or less.

### Claim 7 (depends on 4)

The gas sensor element according to claim 4, wherein
the intermediate measurement electrode layer of the reference electrode comprises a plurality of layers.

### Claim 8 (depends on 1)

The gas sensor element according to claim 1, wherein
the noble metal particles comprise Pt or an alloy of Pt and at least one type selected from a group consisting of Rh, Pd, Au, and Ag.

### Claim 9 (depends on 1)

A gas sensor comprising the gas sensor element according to claim 1.