US4514478A
Expired / Lapsed
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Method of making a porous carbon cathode, a porous carbon cathode so made, and electrochemical cell including the porous carbon cathode
Assignee: United States Department of the Army
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Filing: 1984-08-13
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Granted: 1985-04-30
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Expires: 2004-08-13
Abstract
Abstract A porous carbon cathode for use in an electrochemical cell is made by wetg the carbon black with a 1:1 to 1:3 mixture of isopropyl alcohol:water, adding a binding agent thereto, smearing the resulting stiff paste on a thin expanded metal screen and pressing and rolling to the desired thickness, drying the cathode sheet in a vacuum oven at about 100° C. for one hour while a weight is placed above and below the cathode sheet which is sandwiched between two pieces of blotting paper, the total weight applied being sufficient for the cathode to retain structural integrity, removing the weight and blotting papers and inserting the cathode sheet in an elevated drying oven at about 280° C. for about one hour, and cooling the cathode sheet between blotting paper, repressing and rolling. Cathodes prepared by this method appear structurally strong, maintain their physical integrity with a minimum of cracking and flaking, and do not crumble when cut. The porous carbon cathode is particularly advantageous when included in a lithium sulfuryl chloride cell, but can be used in any system requiring porous carbon cathodes.
Inventors
- 👤 Michael Binder
- 👤 Eric R. Petersen
- 👤 Charles W. Walker, Jr.
- 👤 William L. Wade, Jr.
- 👤 Sol Gilman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 14:56
CPC Classifications
H; H01; H01M; H01M4/00; H01M4/86; H01M4/96; H01M6/00; H01M6/14; Y; Y02; Y02E; Y02E60/00; Y02E60/30; Y02E60/50; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/49108; Y10T29/49115
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
143 words
Method of making a porous carbon cathode for an electrochemical cell, said method including the steps of (A) wetting the carbon black with a 1:1 to 1:3 mixture of isopropyl alcohol:water, (B) adding a binding agent thereto, (C) smearing the resulting stiff paste on a thin expanded metal screen and pressing and rolling to the desired thickness, (D) drying the cathode sheet in a vacuum oven at about 100° C. for about one hour while weight is placed above and below the cathode sheet which is sandwiched between two pieces of blotting paper, the total weight applied being sufficient for the cathode to retain structural integrity, (E) removing the weight and blotting paper and inserting the cathode sheet in an elevated drying oven at about 280° C. for about one hour, and (F) cooling the cathode sheet between blotting paper, repressing, and rolling.
Claim 2
Dependent Claim
143 words
Method of making a porous carbon cathode for an electrochemical cell, said method including the steps of (A) wetting the carbon black with a 1:1 to 1:3 mixture of isopropyl alcohol:water, (B) adding a binding agent thereto, (C) smearing the resulting stiff paste on a thin expanded metal screen and pressing and rolling to the desired thickness, (D) drying the cathode sheet in a vacuum oven at about 100° C. for about one hour while weight is placed above and below the cathode sheet which is sandwiched between two pieces of blotting paper, the total weight applied being sufficient for the cathode to retain structural integrity, (E) removing the weight and blotting paper and inserting the cathode sheet in an elevated drying oven at about 280° C. for about one hour, and (F) cooling the cathode sheet between blotting paper, repressing, and rolling.
Claim 3
Dependent Claim
22 words
Method according to claim 1 wherein the carbon black is a higher surface area carbon black with surface areas≧250 m 2 /g.
Claim 4
Dependent Claim
16 words
Method according to claim 1 wherein the carbon black has a surface area≦250 m 2 /g.
Claim 5
Dependent Claim
11 words
Method according to claim 1 wherein the binding agent is polytetrafluoroethylene.
Claim 6
Dependent Claim
15 words
Method according to claim 1 wherein the electrochemical cell is a lithium sulfuryl chloride cell.
Claim 7
Dependent Claim
35 words
Method according to claim 1 wherein the total weight applied to the cathode sheet is between about 0.1 lb per square inch of cathode sheet to about 2 lbs per square inch of cathode sheet.
Claim 8
Dependent Claim
145 words
A porous carbon cathode for use in an electrochemical cell, said porous carbon cathode being made by the steps of: (A) wetting the carbon black with a 1:1 to 1:3 mixture of isopropyl alcohol:water, (B) adding a binding agent thereto, (C) smearing the resulting stiff paste on a thin expanded metal screen and pressing and rolling to the desired thickness, (D) drying the cathode sheet in a vacuum oven at about 100° C. for about one hour while a weight is placed above and below the cathode sheet which is sandwiched between two pieces of blotting paper, the total weight applied being sufficient for the cathode to retain structural integrity, (E) removing the weight and blotting paper and inserting the cathode sheet in an elevated drying oven at 280° C. for one hour, and (F) cooling the cathode sheet between blotting paper, repressing, and rolling.
Claim 9
Dependent Claim
145 words
A porous carbon cathode for use in an electrochemical cell, said porous carbon cathode being made by the steps of: (A) wetting the carbon black with a 1:1 to 1:3 mixture of isopropyl alcohol:water, (B) adding a binding agent thereto, (C) smearing the resulting stiff paste on a thin expanded metal screen and pressing and rolling to the desired thickness, (D) drying the cathode sheet in a vacuum oven at about 100° C. for about one hour while a weight is placed above and below the cathode sheet which is sandwiched between two pieces of blotting paper, the total weight applied being sufficient for the cathode to retain structural integrity, (E) removing the weight and blotting paper and inserting the cathode sheet in an elevated drying oven at 280° C. for one hour, and (F) cooling the cathode sheet between blotting paper, repressing, and rolling.
Claim 10
Dependent Claim
24 words
A porous carbon cathode according to claim 7 wherein the carbon black is a higher surface area carbon black with areas≧250 m 2 /g.
Claim 11
Dependent Claim
19 words
A porous carbon cathode according to claim 7 wherein the carbon black has a surface area≦250 m 2 /g.
Claim 12
Dependent Claim
14 words
A porous carbon cathode according to claim 7 wherein the binding agent is polytetrafluoroethylene.
Claim 13
Dependent Claim
16 words
A porous carbon cathode according to claim 7 for use in a lithium sulfuryl cloride cell.
Claim 14
Dependent Claim
38 words
A porous carbon cathode according to claim 7 wherein the total weight applied to the cathode sheet is between about 0.1 lb per square inch of cathode sheet to about 2 lbs per square inch of cathode sheet.
Claim 15
Dependent Claim
161 words
An electrochemical cell comprising lithium as the anode, a solution of 1 molar lithium aluminum chloride in sulfuryl chloride as the electrolyte and a porous carbon cathode, said porous carbon cathode being made by the steps of: (A) wetting the carbon black with a 1:1 to 1:3 mixture of isopropyl alcohol:water, (B) adding a binding agent thereto, (C) smearing the resulting stiff paste on a thin expanded metal screen and pressing and rolling to the desired thickness, (D) drying the cathode sheet in a vacuum oven at about 100° C. for one hour while a weight is placed above and below the cathode sheet which is sandwiched between two pieces of blotting paper, the total weight applied being sufficient for the cathode to retain structural integrity, (E) removing the weight and blotting paper and inserting the cathode sheet in an elevated drying oven at 280° C. for one hour, and (F) cooling the cathode sheet between blotting paper, repressing, and rolling.
Claim 16
Dependent Claim
161 words
An electrochemical cell comprising lithium as the anode, a solution of 1 molar lithium aluminum chloride in sulfuryl chloride as the electrolyte and a porous carbon cathode, said porous carbon cathode being made by the steps of: (A) wetting the carbon black with a 1:1 to 1:3 mixture of isopropyl alcohol:water, (B) adding a binding agent thereto, (C) smearing the resulting stiff paste on a thin expanded metal screen and pressing and rolling to the desired thickness, (D) drying the cathode sheet in a vacuum oven at about 100° C. for one hour while a weight is placed above and below the cathode sheet which is sandwiched between two pieces of blotting paper, the total weight applied being sufficient for the cathode to retain structural integrity, (E) removing the weight and blotting paper and inserting the cathode sheet in an elevated drying oven at 280° C. for one hour, and (F) cooling the cathode sheet between blotting paper, repressing, and rolling.
Claim 17
Dependent Claim
23 words
An electrochemical cell according to claim 13 wherein the carbon black is a higher surface area carbon black with areas≧250 m 2 /g.
Claim 18
Dependent Claim
18 words
An electrochemical cell according to claim 13 wherein the carbon black has a surface area≦250 m 2 /g.
Claim 19
Dependent Claim
13 words
An electrochemical cell according to claim 13 wherein the binding agent is polytetrafluoroethylene.
Claim 20
Dependent Claim
37 words
An electrochemical cell according to claim 13 wherein the total weight applied to the cathode sheet is between about 0.1 lb per square inch of cathode sheet to about 2 lbs per square inch of cathode sheet.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-04-29 | 1988-10-29 | 1989-04-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-04-29 | 1992-10-29 | 1993-04-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-04-29 | 1996-10-29 | 1997-04-30 | $7700.00 | Window Closed / Lapsed |