Electrochemical gas sensor, liquid electrolyte and use of a liquid electrolyte in an electrochemical gas sensor

• US 10,175,191 B2
• Filed: 09/01/2014
• Issued: 01/08/2019
• Est. Priority Date: 09/09/2013
• Status: Active Grant

• Current Assignee: Draeger Safety Incorporated (Dragerwerk AG)
• Original Assignee: Draeger Safety Incorporated (Dragerwerk AG)
• Inventors: Nauber, Andreas, Sick, Michael, Steiner, Gregor, Mattern-Fruhwald, Marie-Isabell, Mett, Frank, Chrzan, Rigobert, Sommer, Sabrina
• Primary Examiner(s): Kaur, Gurpreet
• Assistant Examiner(s): Rosenwald, Steven E
• Application Number:
  US14/889,968
• Publication Number:
  US 20160103092A1
• Time in Patent Office: 1,590 Days
• Field of Search: None
• CPC Class Codes: G01N 27/301 Reference electrodes
• CPC Class Codes: G01N 27/4045 for gases other than oxygen
• CPC Class Codes: G01N 27/413 Concentration cells using liquid electrolytes measuring currents or voltages in voltaic cells
• CPC Class Codes: G01N 33/0054 for ammonia
• CPC Class Codes: H01G 11/58 Liquid electrolytes
• CPC Class Codes: H01G 9/035 Liquid electrolytes, e.g. impregnating materials H01G11/54 takes precedence
• CPC Class Codes: H01M 2300/0011 Sulfuric acid-based
• CPC Class Codes: Y02A 50/20 Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters

Abstract

An electrochemical gas sensor (10) has a housing (20), a working electrode (51), a counterelectrode (52) and a reference electrode (53). The housing (20) has an electrolyte reservoir (30), a gas inlet orifice (21) and at least one gas outlet orifice (22). The electrolyte reservoir (30) is filled with a liquid electrolyte (40). The gas sensor (10) has a counterelectrode carrier (26). The counterelectrode (52) is suspended on the counterelectrode carrier (26) in such a way that the counterelectrode (52) is suspended in the electrolyte reservoir (30) and the electrolyte (40) flows around the counterelectrode (52) on all sides. Preferably, the electrolyte includes (I) a solvent, e.g. water, propylene carbonate, ethylene carbonate or mixtures thereof; (ii) a conductive salt, especially an ionic liquid; and/or (iii) an organic mediator, for example substituted quinones, anthraquinones, etc.

Claims

1. An electrochemical gas sensor comprising:

a housing;

a working electrode;

a counterelectrode;

a reference electrode, wherein the housing has an electrolyte reservoir, a gas inlet opening and at least one gas outlet opening;

a liquid electrolyte in the electrolyte reservoir;

a separating element; and

a counterelectrode carrier comprising a radial spoke extending between the separating element and the housing, the counterelectrode being suspended on the radial spoke such that the counterelectrode is suspended in the electrolyte reservoir and the electrolyte flows around the counterelectrode on all sides.

2. A gas sensor according to claim 1, wherein the separating element divides the housing into an upper chamber and a lower chamber.

3. A gas sensor according to claim 2, wherein the upper chamber forms the electrolyte reservoir.

4. A gas sensor according to claim 2, wherein the working electrode is arranged in the lower chamber.

5. A gas sensor according to claim 2, wherein the separating element is configured to guide electrolyte through the separating element from the upper chamber into the lower chamber.

6. A gas sensor according to claim 2, wherein the separating element has at least one top part and one foot part.

7. A gas sensor according to claim 2, wherein the counterelectrode carrier is part of the separating element.

8. A gas sensor according to claim 1, further comprising a collecting electrode, the housing comprising a bottom housing portion, the reference electrode being located at a spaced location from the counterelectrode, the reference electrode extending downward from another radial spoke of the counterelectrode carrier in a direction of the bottom housing portion.

9. A gas sensor according to claim 1, wherein the electrolyte contains at least one solvent and at least one of a conductive salt and an organic mediator.

10. A gas sensor according to claim 9, wherein the solvent is selected from the group containing water and alkylene carbonate, propylene carbonate, ethylene carbonate or mixtures thereof.

11. A gas sensor according to claim 9, wherein the conductive salt is an ionic liquid, an inorganic salt or a mixture of an ionic liquid and an inorganic salt, wherein the anion is selected from the group containing halides, carbonate, sulfonate, phosphate and phosphonate and wherein the cation is preferably selected from the group containing metal ions, onium ions or a mixture of metal ions and onium ions.

12. A gas sensor according to claim 9, wherein the organic mediator has a quinoid system selected from the group containing ortho-quinones, para-quinones, substituted ortho-quinones and substituted para-quinones, dihydroxynaphthalene, substituted dihydroxynaphthalene, anthraquinone, substituted anthraquinone, selected from the group containing 1,2-dihydroxybenzene, 1,4-dihydroxybenzene, 1,4-naphthodihydroxybenzene, substituted 1,2-dihydroxybenzene, substituted 1,4-dihydroxybenzene, substituted 1,4-naphthodihydroxybenzene, selected from the group containing substituted anthraquinone, substituted 1,2-dihydroxybenzene, and substituted 1,4-dihydroxybenzene.

13. A gas sensor according to claim 1, wherein the electrolyte contains a buffer comprising a compound according to

R¹—

(CR²R³)_n—

SO₃H, 

 

Formula I

in which n=1, 2, 3, 4 or 5, wherein all R² and R³ are selected, independently from one another, from among H, NH and OH, and wherein R¹ is selected from the group containing piperazinyl, substituted piperazinyl, N-morpholino, cycloalkyl, and tris-(hydroxyalkyl)alkyl.

14. A gas sensor according to claim 9, wherein the electrolyte is a composition comprising:

a solvent, which is selected from the group comprising water, propylene carbonate, ethylene carbonate and mixtures thereof;

a conductive salt, which is selected from the group comprising 1-hexyl-3-methylimidazolium-tris(pentafluoroethyl)trifluorophosphate and tetraalkylammonium, toluene sulfate; and

an organic mediator, which is selected from the group containing substituted anthraquinone, substituted 1,2-hydroquinone, substituted 1,4-hydroquinone, especially preferably tert.-butyl-hydroquinone and anthraquinone-2-sulfonic acid; and

a buffer, which is selected from a compound lowering the freezing point of the composition, selected from the group containing propylene glycol and ethylene glycol.

15. A gas sensor according to claim 1, wherein the counterelectrode carrier comprises another radial spoke extending between the separating element and the housing, the reference electrode being suspended from the another radial spoke.

16. A gas sensor according to claim 15, wherein the radial spoke is located opposite the another radial spoke.

17. A gas sensor according to claim 16, wherein the reference electrode is located opposite the counterelectrode.

18. A gas sensor according to claim 1, wherein the working electrode is located at a position below the separating element.

19. An electrochemical gas sensor comprising:

a housing comprising a lateral side wall;

a working electrode;

a counterelectrode;

a reference electrode, wherein the housing has an electrolyte reservoir, a gas inlet opening and at least one gas outlet opening;

a liquid electrolyte in the electrolyte reservoir; and

a counterelectrode carrier comprising a first portion extending radially inward from the lateral side wall to at least a position located in an interior of the housing and a second portion extending in a downward direction, the counterelectrode being connected to the first portion of the counterelectrode carrier via the second portion of the counterelectrode carrier portion such that the counterelectrode is suspended in the electrolyte reservoir and the electrolyte flows around the counterelectrode on all sides.

20. A gas sensor according to claim 19, further comprising:

a separating element, the first portion extending between the separating element and the lateral side wall.

21. A gas sensor according to claim 20, wherein the counterelectrode carrier comprises a radial spoke extending between the separating element and the housing, the reference electrode being suspended from the radial spoke.

22. A gas sensor according to claim 21, wherein the radial spoke is located opposite the first portion.

23. A gas sensor according to claim 22, wherein the reference electrode is located opposite the counterelectrode.