US2001034934A1PendingUtilityA1
Electrochemical cells with high volumetric density of electroactive sulfur-containing materials in cathode active layers
Priority: Dec 17, 1998Filed: May 23, 2001Published: Nov 1, 2001
Est. expiryDec 17, 2018(expired)· nominal 20-yr term from priority
Y10T29/49108H01M 4/136H01M 4/0435H01M 4/0483H01M 4/0409H01M 4/5815H01M 4/581H01M 2010/4292H01M 2004/028H01M 4/622H01M 4/1397H01M 10/0525H01M 4/405H01M 4/382H01M 4/0404H01M 4/04Y02P70/50H01M 4/36Y02E60/10
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Claims
Abstract
The present invention pertains to methods of forming solid composite cathodes with cathode active layers which comprise an electroactive sulfur-containing material and an electrically conductive material, wherein the electroactive sulfur-containing material is heated to a temperature above its melting point to form a melt layer and then is resolidified to form a cathode active layer having redistributed electroactive sulfur-containing material of high volumetric density and improved adhesion and cohesion. The present invention also pertains to methods of forming electric current producing cells comprising such solid composite cathodes and having a high electrochemical utilization and to solid composite cathodes and electric current producing cells formed using such methods.
Claims
exact text as granted — not AI-modified1 . A method of forming a solid composite cathode for use in an electric current producing cell, wherein said method comprises the steps of:
(a) dispersing or suspending:
(i) an electroactive sulfur-containing material; and,
(ii) an electrically conductive material;
in a liquid medium to form a liquid mixture; (b) casting said liquid mixture formed in step (a) onto a substrate to form a cast layer; (c) removing some or all of said liquid medium from said cast layer formed in step (b) to form a dried layer on said substrate; (d) melting said electroactive sulfur-containing material in said dried layer by heating to a temperature above the melting point of said electroactive sulfur-containing material to form a melt layer; and, (e) resolidifying said melted electroactive sulfur-containing material formed in step (d) to form a cathode active layer having redistributed electroactive sulfur-containing material, wherein said redistributed electroactive sulfur-containing material is present in said cathode active layer at a volumetric density of greater than 500 mg/cm 3 .
2 . The method of claim 1 , wherein, prior to step (d), said dried layer formed in step (c) is compressed by calendering.
3 . The method of claim 1 , wherein, prior to step (e), said melt layer formed in step (d) is compressed by calendering.
4 . The method of claim 1 , wherein, after forming said redistributed electroactive sulfur-containing material in step (e), there is a further step of compressing said cathode active layer.
5 . The method of claim 1 , wherein said redistributed electroactive sulfur-containing material is present in an amount of 60 to 95 percent by weight of said cathode active layer.
6 . The method of claim 1 , wherein said redistributed electroactive sulfur-containing material is present in an amount of 65 to 90 percent by weight of said cathode active layer.
7 . The method of claim 1 , wherein said redistributed electroactive sulfur-containing material is present in an amount of 70 to 85 percent by weight of said cathode active layer.
8 . The method of claim 1 , wherein said redistributed electroactive sulfur-containing material is present in said cathode active layer at a volumetric density of greater than 700 mg/cm 3 .
9 . The method of claim 1 , wherein said redistributed electroactive sulfur-containing material is present in said cathode active layer at a volumetric density of greater than 1000 mg/cm 3 .
10 . The method of claim 1 , said redistributed electroactive sulfur-containing material is present in said cathode active layer at a volumetric density of greater than 1500 mg/cm 3 .
11 . The method of claim 1 , wherein said electroactive sulfur-containing material comprises elemental sulfur.
12 . The method of claim 1 , wherein said electroactive sulfur-containing material comprises a sulfur-containing polymer comprising a polysulfide moiety, S m , selected from the group consisting of: covalent —S m — moieties, ionic —S m − moieties, and ionic S m 2− moieties, wherein m is an integer equal to or greater than 3.
13 . The method of claim 1 , wherein said temperature in step (d) is greater than 120° C.
14 . The method of claim 1 , wherein said temperature in step (d) is greater than 140° C.
15 . The method of claim 1 , wherein said temperature in step (d) is greater than 160° C.
16 . The method of claim 1 , wherein said electrically conductive material is selected from the group consisting of:
conductive carbons, conductive graphites, electrically conductive polymers, electrically conductive metal chalcogenides, carbon nanofibers, active carbon fibers, metal particles, metal fibers, and metal flakes.
17 . The method of claim 1 , wherein said liquid mixture formed in step (a) and said cathode active layer formed in step (e) further comprise an organic polymeric binder.
18 . The method of claim 1 , wherein said liquid mixture formed in step (a) and said cathode active layer formed in step (e) further comprise an ionically conductive material.
19 . A method of forming a solid composite cathode for use in an electric current producing cell, wherein said method comprises the steps of:
(a) dispersing or suspending:
(i) an electroactive sulfur-containing material; and,
(ii) an electrically conductive material;
in a liquid medium to form a liquid mixture wherein said liquid mixture does not comprise a polymeric binder; (b) casting said liquid mixture formed in step (a) onto a substrate to form a cast layer; (c) removing some or all of said liquid medium from said cast layer formed in step (b) to form a dried layer on said substrate; (d) melting said electroactive sulfur-containing material in said dried layer by heating to a temperature above the melting point of said electroactive sulfur-containing material to form a melt layer; and, (e) resolidifying said melted electroactive sulfur-containing material formed in step (d) to form a cathode active layer having redistributed electroactive sulfur-containing material, wherein said redistributed electroactive sulfur-containing material is present in said cathode active layer at a volumetric density of greater than 500 mg/cm 3 , and wherein said cathode active layer does not comprise a polymeric binder.
20 . The method of claim 19 , wherein, prior to step (d), said dried layer formed in step (c) is compressed by calendering.
21 . The method of claim 19 , wherein, prior to step (e), said melt layer formed in step (d) is compressed by calendering.
22 . The method of claim 19 , wherein, after forming said redistributed electroactive sulfur-containing material in step (e), there is a further step of compressing said cathode active layer.
23 . The method of claim 19 , wherein said redistributed electroactive sulfur-containing material is present in an amount of 60 to 95 percent by weight of said cathode active layer.
24 . The method of claim 19 , wherein said redistributed electroactive sulfur-containing material is present in an amount of 65 to 95 percent by weight of said cathode active layer.
25 . The method of claim 19 , wherein said redistributed electroactive sulfur-containing material is present in an amount of 70 to 95 percent by weight of said cathode active layer.
26 . The method of claim 19 , wherein said redistributed electroactive sulfur-containing material is present in said cathode active layer at a volumetric density of greater than 700 mg/cm 3 .
27 . The method of claim 19 , wherein said redistributed electroactive sulfur-containing material is present in said cathode active layer at a volumetric density of greater than 100 mg/cm 3 .
28 . The method of claim 19 , wherein said redistributed electroactive sulfur-containing material is present in said cathode active layer at a volumetric density of greater than 1500 mg/cm 3 .
29 . A method of forming a solid composite cathode for use in an electric current producing cell, wherein said method comprises the steps of:
(a) dispersing or suspending:
(i) an electroactive sulfur containing material; and,
(ii) an electrically conductive material;
in a liquid medium to form a liquid mixture wherein said liquid mixture does not comprise an ionically conductive material; (b) casting said liquid mixture formed in step (a) onto a substrate to form a cast layer; (c) removing some or all of said liquid medium firm said cast layer formed in step (b) to form a dried layer on said substrate; (d) melting said electroactive sulfur-containing material in said dried layer by heating to a temperature above the melting point of said electroactive sulfur-containing material to form a melt layer; and, (e) resolidifying said melted electroactive sulfur-containing material formed in step (d) to form a cathode active layer having redistributed electroactive sulfur-containing material, wherein said redistributed electroactive sulfur-containing material is present in said cathode active layer at a volumetric density of greater than 500 mg/cm 3 , and wherein said cathode active layer does not comprise an ionically conductive material.
30 . The method of claim 29 , wherein, prior to step (d), said dried layer formed in step (c) is compressed by calendering.
31 . The method of claim 29 , wherein, prior to step (e), said melt layer formed in step (d) is compressed by calendering.
32 . The method of claim 29 , wherein, after forming said redistributed electroactive sulfur-containing material in step (e), there is a further step of compressing said cathode active layer.
33 . The method of claim 29 , wherein said redistributed electroactive sulfur-containing material is present in an amount of 60 to 95 percent by weight of said cathode active layer.
34 . The method of claim 29 , wherein said redistributed electroactive sulfur-containing material is present in an amount of 65 to 95 percent by weight of said cathode active layer.
35 . The method of claim 29 , wherein said redistributed electroactive sulfur-containing material is present in an amount of 70 to 95 percent by weight of said cathode active layer.
36 . The method of claim 29 , wherein said redistributed electroactive sulfur-containing material is present in said cathode active layer at a volumetric density of greater than 700 mg/cm 3 .
37 . The method of claim 29 , wherein said redistributed electroactive sulfur-containing material is present in said cathode active layer at a volumetric density of greater than 1000 mg/cm 3 .
38 . The method of claim 29 , wherein said redistributed electroactive sulfur-containing material is present in said cathode active layer at a volumetric density of greater than 1500 mg/cm 3 .
39 . A solid composite cathode for use in an electric current producing cell formed by the method of claim 1 .
40 . A solid composite cathode for use in an electric current producing cell formed by the method of claim 5 .
41 . A solid composite cathode for use in an electric current producing cell formed by the method of claim 6 .
42 . A solid composite cathode for use in an electric current producing cell formed by the method of claim 7 .
43 . A solid composite cathode for use in an electric current producing cell formed by the method of claim 8 .
44 . A solid composite cathode for use in an electric current producing cell formed by the method of claim 9 .
45 . A solid composite cathode for use in an electric current producing cell formed by the method of claim 10 .
46 . A solid composite cathode for use in an electric, current producing cell formed by the method of claim 11 .
47 . A solid composite cathode for use in an electric current producing cell formed by the method of claim 12 .
48 . A solid composite cathode of claim 47 , wherein m is an integer equal to or greater than 8.
49 . A solid composite cathode of claim 47 , wherein said sulfur-containing polymer has a polymer backbone chain and said polysulfide moiety, S m , is covalently bonded by one or both of its terminal sulfur atoms on a side group to said polymer backbone chain.
50 . A solid composite cathode of claim 47 , wherein said sulfur-containing polymer has a polymer backbone chain and said polysulfide moiety, S m , is incorporated into said polymer backbone chain by covalent bonding of terminal sulfur atoms of said polysulfide moiety.
51 . A solid composite cathode of claim 47 , wherein said sulfur-containing polymer comprises greater than 75 weight percent of sulfur.
52 . A solid composite cathode for use in an electric current producing cell formed by the method of claim 13 .
53 . A solid composite cathode for use in an electric current producing cell formed by the method of claim 14 .
54 . A solid composite cathode for use in an electric current producing cell formed by the method of claim 15 .
55 . A solid composite cathode for use in an electric current producing cell formed by the method of claim 16 .
56 . A solid composite cathode for use in an electric current producing cell formed by the method of claim 17 .
57 . The solid composite cathode of claim 56 , wherein said polymeric binder is present in an amount less than 10 percent by weight of said cathode active layer.
58 . The solid composite cathode of claim 56 , wherein said polymeric binder is present in an amount less than 6 percent of said cathode active layer.
59 . The solid composite cathode of claim 56 , wherein said polymeric binder is present in an amount less than 3 percent of said cathode active layer.
60 . A solid composite cathode for use in an electric current producing cell formed by the method of claim 19 .
61 . A solid composite cathode for use in an electric current producing cell formed by the method of claim 23 .
62 . A solid composite cathode for use in an electric current producing cell formed by the method of claim 24 .
63 . A solid composite cathode for use in an electric current producing cell formed by the method of claim 25 .
64 . A solid composite cathode for use in an electric current producing cell formed by the method of claim 26 .
65 . A solid composite cathode for use in an electric current producing cell formed by the method of claim 27 .
66 . A solid composite cathode for use in an electric current producing cell formed by the method of claim 28 .
67 . A solid composite cathode of claim 60 , wherein sad cathode active layer further comprises an ionically conductive material.
68 . The solid composite cathode of claim 67 , wherein said ionic ally conductive material is present in an amount less than 10 percent by weight of said cathode active layer.
69 . The solid composite cathode of claim 67 , wherein said ionically conductive material is present in an amount less than 6 percent of said cathode active layer.
70 . The solid composite cathode of claim 67 , wherein said ionically conductive material is present in an amount less than 3 percent of said cathode active layer.
71 . A solid composite cathode of claim 60 , wherein said electrically conductive material is selected from the group consisting of:
conductive carbons, conductive graphites, electrically conductive polymers, electrically conductive metal chalcogenides, carbon nanofibers, active carbon fibers, metal particles, metal fibers, and metal flakes.
72 . A solid composite cathode for use in an electric current producing cell formed by the method of claim 29 .
73 . A solid composite cathode for use in an electric current producing cell formed by the method of claim 33 .
74 . A solid composite cathode for use in an electric current producing cell formed by the method of claim 34 .
75 . A solid composite cathode for use in an electric current producing cell formed by the method of claim 35 .
76 . A solid composite cathode for use in an electric current producing cell formed by the method of claim 36 .
77 . A solid composite cathode for use in an electric current producing cell formed by the method of claim 37 .
78 . A solid composite cathode for use in an electric current producing cell formed by the method of claim 38 .
79 . A solid composite cathode of claim 72 , wherein said electrically conductive material is selected from the group consisting of:
conductive carbons, conductive graphites, electrically conductive polymers, electrically conductive metal chalcogenides, carbon nanofibers, active carbon fibers, metal particles, metal fibers, and metal flakes.
80 . A method of forming an electric current producing cell, wherein said method comprises the steps of:
(i) providing an anode; (ii) providing a solid composite cathode according to claim 1 ; and, (iii) interposing an electrolyte between said anode and said cathode.
81 . A method of forming an electric current producing cell, wherein said method comprises the steps of:
(i) providing an anode; (ii) providing a solid composite cathode according to claim 19 ; and, (iii) interposing an electrolyte between said anode and said cathode.
82 . A method of forming an electric current producing cell, wherein said method comprises the steps of:
(i) providing an anode; (ii) providing a solid composite cathode according to claim 29 ; and, (iii) interposing an electrolyte between said anode and said cathode.
83 . An electric current producing cell comprising:
(a) an anode; (b) a solid composite cathode according to claim 39 ; and, (c) an electrolyte interposed between said anode and said cathode.
84 . The cell of claim 83 , wherein said cathode active layer, upon discharge, has a volumetric capacity greater than 500 mAh/cm 3 .
85 . The cell of claim 83 , wherein said cathode active layer, upon discharge, has a volumetric capacity greater than 600 mAh/cm 3 .
86 . The cell of claim 83 , wherein said cathode active layer, upon discharge, has a volumetric capacity greater than 700 mAh/cm 3 .
87 . The cell of claim 83 , wherein said cathode active layer, upon discharge, has a volumetric capacity greater than 900 mAh/cm 3 .
88 . The cell of claim 83 , wherein said cathode active layer, upon discharge, has a volumetric capacity greater than 1100 mAh/cm 3 .
89 . The cell of claim 83 , wherein said anode comprises one or more anode active materials selected from the group consisting of:
lithium metal, lithium-aluminum alloys, lithium-tin alloys, lithium-intercalated carbons, and lithium-intercalated graphites.
90 . The cell of claim 83 , wherein said electrolyte comprises one or more materials selected from the group consisting of:
liquid electrolytes, gel polymer electrolytes, and solid polymer electrolytes.
91 . The cell of claim 83 , wherein said electrolyte comprises:
(a) one or more polymers selected from the group consisting of: polyethers, polyethylene oxides, polypropylene oxides, polyimides, polyphosphazenes, polyacrylonitriles, polysiloxanes; derivatives of the foregoing; copolymers of the foregoing; and blends of the foregoing; and, (b) one or more ionic electrolyte salts.
92 . The cell of claim 83 , wherein said electrolyte comprises:
(a) one or more electrolyte solvents selected from the group consisting of: N-methyl acetamide, acetonitrile, carbonates, sulfolanes, N-alkyl pyrrolidones, dioxolanes, glymes, aliphatic ethers, cyclic ethers, and siloxanes; and, one or more electrolyte salts.
93 . An electric current producing cell comprising:
(a) an anode; (b) a solid composite cathode according to claim 60 ; and, (c) an electrolyte interposed between said anode and said cathode.
94 . The cell of claim 93 , wherein said cathode active layer, upon discharge, has a volumetric capacity greater than 500 mAh/cm 3 .
95 . The cell of claim 93 , wherein said cathode active layer, upon discharge, has a volumetric capacity greater than 600 mAh/cm 3 .
96 . The cell of claim 93 , wherein said cathode active layer, upon discharge, has a volumetric capacity greater than 700 mAh/cm 3 .
97 . The cell of claim 93 , wherein said cathode active layer, upon discharge, has a volumetric capacity greater than 900 mAh/cm 3 .
98 . The cell of claim 93 , wherein said cathode active layer, upon discharge, has a volumetric capacity greater than 1100 mAh/cm 3 .
99 . An electric current producing cell comprising:
(a) an anode; (b) a solid composite cathode according to claim 72 ; and, (c) an electrolyte interposed between said anode and said cathode.
100 . The cell of claim 99 , wherein said cathode active layer, upon discharge, has a volumetric capacity greater than 500 mAh/cm 3 .
101 . The cell of claim 99 , wherein said cathode active layer, upon discharge, has a volumetric capacity greater than 600 mAh/cm 3 .
102 . The cell of claim 99 , wherein said cathode active layer, upon discharge, has a volumetric capacity greater than 700 mAh/cm 3 .
103 . The cell of claim 99 , wherein said cathode active layer, upon discharge, has a volumetric capacity greater than 900 mAh/cm 3 .
104 . The cell of claim 99 , wherein said cathode active layer, upon discharge, has a volumetric capacity greater than 1100 mAh/cm 3 .Join the waitlist — get patent alerts
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