Electrochemical oxygen sensor

Patent metadata

Field	Value
Publication number	US-11733200-B2
Application number	US-201817273553-A
Country	US
Kind code	B2
Filing date	Oct 17, 2018
Priority date	Oct 17, 2018
Publication date	Aug 22, 2023
Grant date	Aug 22, 2023

Abstract

An electrochemical oxygen sensor with a long service life is provided. The electrochemical oxygen sensor according to the present invention includes a positive electrode, a negative electrode, and an electrolyte solution, and the electrolyte solution contains a chelating agent and ammonia, and a concentration of the ammonia in the electrolyte solution is 0.01 mol/L or higher. Citric acid is preferable as the chelating agent contained in the electrolyte solution. Also, the negative electrode preferably contains an Sn alloy.

First claim

The invention claimed is:

1. An electrochemical oxygen sensor comprising:
a positive electrode;
a negative electrode; and
an electrolyte solution,
wherein the electrolyte solution comprises a chelating agent and ammonia,
wherein the electrolyte solution comprises citric acid as the chelating agent, and
wherein a concentration of the ammonia in the electrolyte solution is 0.01 mol/L or higher.

2. The electrochemical oxygen sensor according to claim 1 ,
wherein a concentration of the chelating agent in the electrolyte solution is 2.3 mol/L or higher.

3. The electrochemical oxygen sensor according to claim 1 ,
wherein the electrolyte solution further comprises an alkali metal salt of the chelating agent.

4. The electrochemical oxygen sensor according to claim 1 ,
wherein the electrolyte solution has a pH of 3.5 to 5.75.

5. The electrochemical oxygen sensor according to claim 1 ,
wherein the negative electrode comprises Sn or an Sn alloy.

6. The electrochemical oxygen sensor according to claim 1 ,
wherein the negative electrode comprises an Sn alloy, and
wherein the Sn alloy comprises at least one element selected from the group consisting of Ag, Cu, and Sb.

7. A The electrochemical oxygen sensor according to claim 1 ,
wherein the electrolyte solution further comprises at least one compound selected from the group consisting of acetic acid, boric acid, phosphoric acid, and salts thereof.

8. The electrochemical oxygen sensor according to claim 1 ,
wherein the electrolyte solution has a pH of 7.40 or less.

9. The electrochemical oxygen sensor according to claim 1 ,
wherein the concentration of the ammonia in the electrolyte solution is 0.1 mol/L or higher.

10. The electrochemical oxygen sensor according to claim 1 ,
wherein a content of Pb in the negative electrode is less than 1000 ppm.

11. An electrochemical oxygen sensor comprising:
a positive electrode;
a negative electrode; and
an electrolyte solution,
wherein the negative electrode comprises Sn or an Sn alloy,
wherein the electrolyte solution comprises a chelating agent and ammonia, and
wherein a concentration of the ammonia in the electrolyte solution is 0.01 mol/L or higher.

12. The electrochemical oxygen sensor according to claim 11 ,
wherein a concentration of the chelating agent in the electrolyte solution is 2.3 mol/L or higher.

13. The electrochemical oxygen sensor according to claim 11 ,
wherein the electrolyte solution further comprises an alkali metal salt of the chelating agent.

14. The electrochemical oxygen sensor according to claim 11 ,
wherein the electrolyte solution has a pH of less than 7.

15. The electrochemical oxygen sensor according to claim 11 ,
wherein the negative electrode comprises an Sn alloy, and
wherein the Sn alloy comprises at least one element selected from the group consisting of Ag, Cu, and Sb.

16. The electrochemical oxygen sensor according to claim 11 ,
wherein the electrolyte solution further comprises at least one compound selected from the group consisting of acetic acid, boric acid, phosphoric acid, and salts thereof.

17. The electrochemical oxygen sensor according to claim 11 ,
wherein the concentration of the ammonia in the electrolyte solution is 0.1 mol/L or higher.

18. The electrochemical oxygen sensor according to claim 11 ,
wherein a content of Pb in the negative electrode is less than 1000 ppm.

Assignees

• Maxell Ltd

Inventors

• Kitazawa Naohisa
• Kuromatsu Emi
• Kakeya Tadashi

Classifications

• G01N27/404 Primary

  Cells with anode, cathode and cell electrolyte on the same side of a permeable membrane which separates them from the sample fluid {, e.g. Clark-type oxygen sensors} · CPC title

• G01N27/30

  Electrodes, e.g. test electrodes; Half-cells (G01N27/414 takes precedence) · CPC title

• G01N27/413 Primary

  Concentration cells using liquid electrolytes {measuring currents or voltages in voltaic cells} · CPC title