EP0357077A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Platinum black air cathode, method of operating same, and layered gas diffusion electrode of improved inter-layer bonding
Assignee: Eltech Systems Corp
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Filing: 1989-08-31
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Granted: —
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Expires: 2009-08-31
Abstract
Abstract A platinum black air cathode has an active layer and a support layer. The active layer comprises platinum black plus hydrophobic binder, typically a fluorinated polymer. The support layer may be made up from carbon black bound with a halopolymer binding agent. Such combination can provide for economical utilization of active ingredient without sacrifice of cathode structural integrity. To assist in this structural integrity, a thin support mesh may be used, preferably with the support layer. There can also be employed between the active layer and the support layer a porous bonding layer, which can find broader utilization with layered gas diffusion electrodes in general. For highly desirable, greatly extended operation of the platinum black air cathode, the cathode can be operated intermittently, or anodically polarized or be subjected to infrequent voltage suppression, as well as being involved with any combination of the foregoing.
Inventors
- 👤 Frank Solomon
- 👤 Yury Genodman
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 00:05
CPC Classifications
H; H01; H01M; H01M4/00; H01M4/86; H01M4/96; C; C25; C25B; C25B1/00; C25B1/01; C25B1/13; C25B11/00; C25B11/02; C25B11/03; C25B11/031; C25B11/032; Y; Y02; Y02E; Y02E60/00; Y02E60/30; Y02E60/50; Y10; Y10S; Y10S977/00; Y10S977/70; Y10S977/734; Y10S977/753; Y10S977/773; Y10S977/775; Y10S977/788; Y10S977/84; Y10S977/895; Y10S977/896; Y10S977/898
Claims Analysis
Total Claims: 71
Claim 1
Independent Claim
64 words
An electrode of economical utilization of active ingredient without sacrifice of structural integrity, said electrode comprising an electrically conductive, gas porous and hydrophobic support layer containing an intimate and uniform blend of particulate carbon plus hydrophobic polymer, and an electrolyte porous active layer comprising finely divided platinum catalyst particles intimately blended with, and uniformly distributed throughout, halogenated polymer binder for said platinum catalyst particles.
Claim 2
Dependent Claim
64 words
An electrode of economical utilization of active ingredient without sacrifice of structural integrity, said electrode comprising an electrically conductive, gas porous and hydrophobic support layer containing an intimate and uniform blend of particulate carbon plus hydrophobic polymer, and an electrolyte porous active layer comprising finely divided platinum catalyst particles intimately blended with, and uniformly distributed throughout, halogenated polymer binder for said platinum catalyst particles.
Claim 3
Dependent Claim
20 words
The electrode of claim 1, wherein said electrode is an oxygen reduction cathode capable of functioning in an acid system.
Claim 4
Dependent Claim
31 words
The electrode of claim 1, wherein said active layer contains from about 0.1 to about 10 weight percent of said halogenated polymer binder and a balance of said platinum catalyst particles.
Claim 5
Dependent Claim
21 words
The electrode of claim 1, wherein said active layer halogenated polymer is supplied at least in part from hydrophobic fluorinated polymer.
Claim 6
Dependent Claim
22 words
The electrode of claim 4, wherein said active layer hydrophobic fluorinated polymer is one or more of polytetrafluoroethylene and fluorinated ethylene-propylene copolymer.
Claim 7
Dependent Claim
24 words
The electrode of claim 1, wherein said active layer platinum catalyst is one or more of particulate platinum black and platinum on finely-divided carbon.
Claim 8
Dependent Claim
21 words
The electrode of claim 1, wherein said support layer contains from about 20 to about 60 weight percent of hydrophobic polymer.
Claim 9
Dependent Claim
22 words
The electrode of claim 1, wherein said support layer hydrophobic polymer comprises one or more of halogenated hydrocarbon polymer or hydrocarbon polymer.
Claim 10
Dependent Claim
19 words
The electrode of claim 1, wherein said support layer particulate carbon has particle size less than about 0.3 micron.
Claim 11
Dependent Claim
24 words
The electrode of claim 1, wherein said support layer has a major amount of pore volume in pores of less than 0.2 micron diameter.
Claim 12
Dependent Claim
18 words
The electrode of claim 1, wherein said support layer and said active layer are in adherent, face-to-face contact.
Claim 13
Dependent Claim
17 words
The electrode of claim 1, wherein a foraminous overlay contacts a broad face of said support layer.
Claim 14
Dependent Claim
13 words
An acid electrolyte battery containing an oxygen cathode as defined in claim 1.
Claim 15
Dependent Claim
96 words
In the method of preparing an electrode having an active layer containing particulate platinum catalyst particles bound by polymer binder, the improvement comprising: establishing an electrically conductive, gas porous and hydrophobic support layer containing particulate carbon plus hydrophobic polymer; dispersing together finely divided platinum catalyst plus halogenated polymer in a dispersion liquid medium; depositing the resulting dispersion of platinum catalyst plus halogenated polymer into said gas porous support layer; evaporating liquid medium from the resulting deposit; and sintering the resulting deposited product plus gas porous support layer at elevated temperature and pressure, thereby preparing said electrode.
Claim 16
Dependent Claim
96 words
In the method of preparing an electrode having an active layer containing particulate platinum catalyst particles bound by polymer binder, the improvement comprising: establishing an electrically conductive, gas porous and hydrophobic support layer containing particulate carbon plus hydrophobic polymer; dispersing together finely divided platinum catalyst plus halogenated polymer in a dispersion liquid medium; depositing the resulting dispersion of platinum catalyst plus halogenated polymer into said gas porous support layer; evaporating liquid medium from the resulting deposit; and sintering the resulting deposited product plus gas porous support layer at elevated temperature and pressure, thereby preparing said electrode.
Claim 17
Dependent Claim
18 words
The method of claim 14, wherein said dispersion is deposited by filtering onto said gas porous support layer.
Claim 18
Dependent Claim
19 words
The method of claim 14, wherein said liquid medium is evaporated at moderate temperature for drying said deposited product.
Claim 19
Dependent Claim
32 words
The method of claim 14, wherein said resulting deposited product plus gas porous support layer are sintered at a temperature not above about 350°C. and a pressure not above about 500 psi.
Claim 20
Dependent Claim
18 words
The method of claim 14, wherein there is prepared an oxygen cathode for use with an acid electrolyte.
Claim 21
Dependent Claim
36 words
An electrode in multi-layer form and having enhanced inter-layer bonding, said electrode comprising a gas porous, polymer-containing support layer, a catalyst-containing and polymer-containing active layer and a gas porous intermediate bonding layer of thermoplastic hydrophobic polymer.
Claim 22
Dependent Claim
36 words
An electrode in multi-layer form and having enhanced inter-layer bonding, said electrode comprising a gas porous, polymer-containing support layer, a catalyst-containing and polymer-containing active layer and a gas porous intermediate bonding layer of thermoplastic hydrophobic polymer.
Claim 23
Dependent Claim
19 words
The electrode of claim 19, wherein said support layer is an electrically conductive, gas supplying and hydrophobic support layer.
Claim 24
Dependent Claim
12 words
The electrode of claim 20, wherein said support layer contains particulate carbon.
Claim 25
Dependent Claim
21 words
The electrode of claim 19, wherein said support layer contains from about 20 to about 60 weight percent of hydrophobic polymer.
Claim 26
Dependent Claim
22 words
The electrode of claim 19, wherein said support layer comprises hydrophobic polymer of one or more of hydrocarbon or halogenated hydrocarbon polymer.
Claim 27
Dependent Claim
21 words
The electrode of claim 23, wherein said hydrophobic halogenated polymer is one or more of polytetrafluoroethylene, fluorinated ethylene-propylene copolymer or polychlorofluoroethylene.
Claim 28
Dependent Claim
20 words
The electrode of claim 19, wherein said polymer-containing active layer is an intimate blend of halogenated polymer plus particulate catalyst.
Claim 29
Dependent Claim
12 words
The electrode of claim 19, wherein said active layer polymer is fluoropolymer.
Claim 30
Dependent Claim
26 words
The electrode of claim 26, wherein said active layer fluoropolymer is supplied at least in part by one or more of polytetrafluoroethylene and fluorinated ethylene-propylene copolymer.
Claim 31
Dependent Claim
25 words
The electrode of claim 19, wherein said active layer contains a minor weight amount of said polymer and a major weight amount of said catalyst.
Claim 32
Dependent Claim
23 words
The electrode of claim 19, wherein said catalyst-containing active layer contains catalyst comprising metal catalyst, metal compound catalyst, carbon catalyst and their mixtures.
Claim 33
Dependent Claim
21 words
The electrode of claim 19, wherein said intermediate bonding layer consists essentially of a gas porous discontinuous layer of fluorinated polymer.
Claim 34
Dependent Claim
29 words
The electrode of claim 19, wherein said intermediate bonding layer is present in an amount within the range of from about 0.01 to about 0.4 milligram per square centimeter.
Claim 35
Dependent Claim
21 words
The electrode of claim 19, wherein a foraminous overlay contacts at least one of said support layer or said active layer.
Claim 36
Dependent Claim
12 words
A cell containing a gas diffusion electrode as defined in claim 19.
Claim 37
Dependent Claim
128 words
In the method of preparing an electrode in multi-layer form, with said electrode having enhanced inter-layer bonding, and wherein a polymer-containing, porous support layer is bonded to an active layer containing catalyst particles in finely divided form, and with there being retained in said method desirable porosity for said support layer, which method comprises: establishing said porous support layer; dispersing thermoplastic hydrophobic polymer in liquid medium; depositing the resulting dispersion onto said porous support layer in an amount to provide a final dry polymer deposit in an amount of less than about 0.4 milligram per square centimeter of said support layer; and heat treating said polymer deposit at an elevated temperature below the thermal decomposition temperature of said polymer to bind said polymer deposit and support layer together.
Claim 38
Dependent Claim
128 words
In the method of preparing an electrode in multi-layer form, with said electrode having enhanced inter-layer bonding, and wherein a polymer-containing, porous support layer is bonded to an active layer containing catalyst particles in finely divided form, and with there being retained in said method desirable porosity for said support layer, which method comprises: establishing said porous support layer; dispersing thermoplastic hydrophobic polymer in liquid medium; depositing the resulting dispersion onto said porous support layer in an amount to provide a final dry polymer deposit in an amount of less than about 0.4 milligram per square centimeter of said support layer; and heat treating said polymer deposit at an elevated temperature below the thermal decomposition temperature of said polymer to bind said polymer deposit and support layer together.
Claim 39
Dependent Claim
18 words
The method of claim 34, wherein there is established a gas porous, electrically conductive and hydrophobic support layer.
Claim 40
Dependent Claim
43 words
The method of claim 34, wherein there is established a porous support layer with a porosity wherein a majority of the pore volume is from pores having diameter at least substantially the same as the average particle size of said thermoplastic hydrophobic polymer.
Claim 41
Dependent Claim
17 words
The method of claim 34, wherein said polymer deposit is dried at a temperature below about 200°C.
Claim 42
Dependent Claim
20 words
The method of claim 34, wherein said heat treating is accomplished at a temperature not in excess of about 350°C.
Claim 43
Dependent Claim
11 words
A gas diffusion electrode prepared by the method of claim 34.
Claim 44
Dependent Claim
66 words
A gas diffusion electrode comprising: (a) an electrically conductive, gas porous and hydrophobic support layer comprising an intimate and uniform blend of hydrophobic polymer plus particulate carbon; (b) an electrolyte porous active layer comprising an intimate and uniform blend of finely divided platinum catalyst particles bound with halogenated polymer binder; and (c) a foraminous overlay compressed against a broad face of said gas porous support layer.
Claim 45
Dependent Claim
66 words
A gas diffusion electrode comprising: (a) an electrically conductive, gas porous and hydrophobic support layer comprising an intimate and uniform blend of hydrophobic polymer plus particulate carbon; (b) an electrolyte porous active layer comprising an intimate and uniform blend of finely divided platinum catalyst particles bound with halogenated polymer binder; and (c) a foraminous overlay compressed against a broad face of said gas porous support layer.
Claim 46
Dependent Claim
13 words
The electrode of claim 40, wherein said foraminous overlay is a metal mesh.
Claim 47
Dependent Claim
14 words
An acid electrolyte battery containing a gas diffusion electrode as defined in claim 40.
Claim 48
Dependent Claim
94 words
An electrode comprising: (a) an electrically conductive, gas porous and hydrophobic support layer comprising an intimate and uniform blend of hydrophobic polymer plus particulate carbon; (b) an electrolyte porous active layer comprising an intimate and uniform blend of finely divided platinum catalyst particles bound with halogenated polymer binder; (c) a gas porous intermediate bonding layer, of hydrophobic thermoplastic halogenated polymer, situated between said support layer and said active layer; and (d) a foraminous overlay compressed against a broad face of one or more of said support layer and said active layer of said electrode.
Claim 49
Dependent Claim
94 words
An electrode comprising: (a) an electrically conductive, gas porous and hydrophobic support layer comprising an intimate and uniform blend of hydrophobic polymer plus particulate carbon; (b) an electrolyte porous active layer comprising an intimate and uniform blend of finely divided platinum catalyst particles bound with halogenated polymer binder; (c) a gas porous intermediate bonding layer, of hydrophobic thermoplastic halogenated polymer, situated between said support layer and said active layer; and (d) a foraminous overlay compressed against a broad face of one or more of said support layer and said active layer of said electrode.
Claim 50
Dependent Claim
13 words
The electrode of claim 43, wherein said foraminous overlay is a metal mesh.
Claim 51
Dependent Claim
19 words
The electrode of claim 43, wherein said foraminous overlay is compressed against a broad face of said support layer.
Claim 52
Dependent Claim
10 words
A battery containing an electrode as defined in claim 43.
Claim 53
Dependent Claim
61 words
In the method of operating a gas diffusion electrode in acid electrolyte, wherein said electrode contains catalyst interacting with gas diffusing in said electrode, the improvement comprising impressing an electrical current on said electrode for an interval of closed circuit operation, then providing an open circuit interval for said electrode, and next returning said electrode to closed circuit, impressed current operation.
Claim 54
Dependent Claim
61 words
In the method of operating a gas diffusion electrode in acid electrolyte, wherein said electrode contains catalyst interacting with gas diffusing in said electrode, the improvement comprising impressing an electrical current on said electrode for an interval of closed circuit operation, then providing an open circuit interval for said electrode, and next returning said electrode to closed circuit, impressed current operation.
Claim 55
Dependent Claim
22 words
The method of claim 47, wherein said electrical current on said electrode provides an electrode current density of greater than 10 ma/cm².
Claim 56
Dependent Claim
15 words
The method of claim 47, wherein said electrode operates in said acid electrolyte containing HBF₄.
Claim 57
Dependent Claim
39 words
The method of claim 47, wherein said electrode forms a portion of a cell stack of continuing operation having at least one cell in closed circuit operation while a cell in said stack is in an open circuit interval.
Claim 58
Dependent Claim
28 words
The method of claim 47, wherein said electrode is operated in a closed circuit for from 0.5 to 3 hours and in open circuit for from 1-15 minutes.
Claim 59
Dependent Claim
18 words
The method of claim 47, wherein said electrode is in an open circuit mode periodically at regular intervals.
Claim 60
Dependent Claim
61 words
An electrolytic cell comprising an anode operating in an acid system, an air cathode forming water by reduction of oxygen at the surface of said cathode, a direct current power source operatively connected to said electrodes, and switching means interposed between said power source and said cathode whereby said cathode can be switched to an open circuit mode selectively and intermittently.
Claim 61
Dependent Claim
61 words
An electrolytic cell comprising an anode operating in an acid system, an air cathode forming water by reduction of oxygen at the surface of said cathode, a direct current power source operatively connected to said electrodes, and switching means interposed between said power source and said cathode whereby said cathode can be switched to an open circuit mode selectively and intermittently.
Claim 62
Independent Claim
35 words
The method of operating an electrolytic cell for the production of ozone, said cell containing at least one air cathode for reduction of oxygen, which method is characterized by intermittently anodically polarizing said air cathode.
Claim 63
Independent Claim
35 words
The method of operating an electrolytic cell for the production of ozone, said cell containing at least one air cathode for reduction of oxygen, which method is characterized by intermittently anodically polarizing said air cathode.
Claim 64
Dependent Claim
30 words
The method of claim 54, wherein current is passed through the anodically polarizing air cathode at a current density within the range from about 1 ma/cm² to about 5 ma/cm².
Claim 65
Dependent Claim
16 words
The method of claim 54, wherein said air cathode is anodically polarized periodically at regular intervals.
Claim 66
Dependent Claim
70 words
An electrolytic cell for the production of ozone comprising an anode for forming ozone by oxidation of water at the surface of said anode, an air cathode forming water by reduction of oxygen at the surface of said cathode, a direct current power source operatively connected to said electrodes, and switching means interposed between said power source and said cathode whereby such cathode can be made anodic selectively and intermittently.
Claim 67
Dependent Claim
70 words
An electrolytic cell for the production of ozone comprising an anode for forming ozone by oxidation of water at the surface of said anode, an air cathode forming water by reduction of oxygen at the surface of said cathode, a direct current power source operatively connected to said electrodes, and switching means interposed between said power source and said cathode whereby such cathode can be made anodic selectively and intermittently.
Claim 68
Dependent Claim
35 words
The electrolytic cell of claim 57, wherein said switching means includes means for limiting the current flow to said cathode to a level below about 5 ma/cm² when said cathode is in the anodic mode.
Claim 69
Dependent Claim
36 words
In the method of operating an electrolytic cell for the production of ozone, said cell containing at least one air cathode for reduction of oxygen, which method comprises infrequently suppressing the operating voltage for said cathode.
Claim 70
Dependent Claim
36 words
In the method of operating an electrolytic cell for the production of ozone, said cell containing at least one air cathode for reduction of oxygen, which method comprises infrequently suppressing the operating voltage for said cathode.
Claim 71
Dependent Claim
37 words
The method of claim 59, wherein said operating voltage is suppressed about 0.5 volt as measured against a normal hydrogen on platinum electrode, for a cathode operating at an electrode current density up to about 200 ma/cm².
References Cited (Backward Citations)
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