Flexible, conducting plastic electrode and process for its preparation

Claim 2

A flexible, conducting plastic substrate material for a conducting electrode, said plastic substrate material comprising: (a) a conductive filler material; (b) a thermo-plastic polymer; and (c) an elastomeric polymer at least partially cross-linked with (b); wherein (a) is present in an amount such that the plastic substrate material is electrically conducting and (b) is cross-linked with (c) to a degree such that the plastic substrate material is flexible and has high tensile strength.

Claim 3

An electrode comprising the plastic substrate material of claim 1 and; a further electrode component selected from the group consisting of a metal mesh, a metal sheet, a metal foil, and graphite felt, wherein the further electrode component is pressure and heat welded to the plastic substrate material in a configuration selected from a group consisting of a layer of the plastic substrate material and a layer of the further electrode component, a layer of metal foil between two layers of the plastic substrate material, and a layer of metal mesh between two layers of the plastic substrate material.

Claim 4

The electrode of claim 2 wherein the plastic substrate material comprises: the thermo-plastic polymer in an amount of 30 wt %-60 wt %; the elastomeric polymer cross-linked with thermoplastic polymer in an amount of 10 wt %-30 wt %; and the conductive filler material in an amount of 5-40 wt %; and the further electrode component is a layer of graphite felt heat and pressure fused onto at least one surface of the plastic substrate material.

Claim 5

The plastic substrate material of claim 1 wherein the conductive filler material is selected from the group consisting of carbon black, graphite powder, metal powder, metallized glass fibers, pitch-derived carbon fibers, graphite fibers, polyacrylonitrile-derived carbon fibers and polyacrylonitrile-derived graphite fibers.

Claim 6

The plastic substrate material of claim 4 wherein the conductive filler material comprises carbon black in an amount of 10-70 wt % of the total composition.

Claim 7

The plastic substrate material of claim 4 wherein the conductive filler material comprises a mixture of carbon black and graphite fibers in a weight ratio in the range 5:95 to 95:5 in an amount of 10-70 wt % of the total composition.

Claim 8

The plastic substrate material of claim 6 wherein the carbon black to graphite fibers is in a weight ratio of 50:50.

Claim 9

The plastic substrate material of any one claims 4 to 7 wherein at least two different types of carbon black are used, namely, fine carbon black powder (2-35 nm) and coarse carbon black powder (35 nm-10,000 nm) in a weight ratio of fine carbon:coarse carbon of from 1:99 to 99:1.

Claim 10

The plastic substrate material of claim 4 wherein the weight ratio of carbon black plus graphite fibers content to total polymer is 2:3.

Claim 11

The plastic substrate material of claim 1 wherein the thermo-plastic polymer is 10-80 wt % of the total composition.

Claim 12

The plastic substrate material of claim 1 wherein the thermo-plastic polymer is selected from the group consisting of low density polyethylene, high density polyethylene,, polypropylene, polybutylene and polystyrene.

Claim 13

The plastic substrate material of claim 1 wherein the elastomeric polymer includes at least one or more polymers selected from the group consisting of styrene-isoprene-styrene, nitrile rubber (NBR), ethylene-propylene-diene terpolymer (EPDM), ethylene-propylene copolymer (EP), styrene-butadiene (SB), ethylene-propylene rubber (EPR), n-butyl rubber, styrene-butadiene-styrene, santoprene, and styrene-(ethylene-butylene)-styrene.

Claim 14

The plastic substrate material of claim 1 or 11 wherein the elastomeric polymer is from 1-50 wt % of the total composition.

Claim 15

A process for making a plastic substrate material for a conducting electrode, the process comprising; (a) mixing a thermo-plastic polymer, an elastomeric polymer and conductive filler material, the mixing being at a temperature(s) above the melting point temperatures of the thermo-plastic polymer and the elastomeric polymer, (b) extruding or pressure moulding the mixture of (a) at a temperature(s) above the melting temperatures of the thermo-plastic polymer and the elastomeric polymer until the polymers are at least partially cross-linked wherein the degree of cross-linking of the thermo-plastic with the elastomeric polymer is such that the plastic substrate material is flexible and has high tensile strength, and (c) cooling the cross-linked polymerized mixture of (b) to form the plastic substrate material; wherein an amount of the conductive filler material is such that the plastic substrate material is electrically conducting.

Claim 16

A process for making a plastic substrate material for a conducting electrode, the process comprising; (a) mixing a thermo-plastic polymer, an elastomeric polymer and conductive filler material, the mixing being at a temperature(s) above the melting point temperatures of the thermo-plastic polymer and the elastomeric polymer, (b) extruding or pressure moulding the mixture of (a) at a temperature(s) above the melting temperatures of the thermo-plastic polymer and the elastomeric polymer until the polymers are at least partially cross-linked wherein the degree of cross-linking of the thermo-plastic with the elastomeric polymer is such that the plastic substrate material is flexible and has high tensile strength, and (c) cooling the cross-linked polymerized mixture of (b) to form the plastic substrate material; wherein an amount of the conductive filler material is such that the plastic substrate material is electrically conducting.

Claim 17

The process of claim 14 wherein in step (c) the polymerized mixture of (b) is cooled rapidly.

Claim 18

The process of claim 14 further comprising (b)(i) adding a polymerization initiator to the mixture of (a), and (b)(ii) optionally adding at least one chemical additive to the mixture of (a).

Claim 19

The process of any one claims 14 to 16 further including the step of pressure and heat welding a further electrode component selected from the group consisting of a metal mesh, metal sheet, a metal foil and a graphite felt onto at least one surface of the flexible, conducting plastic substrate material.

Claim 20

The process of any one of claims 14 to 16 wherein the conductive filler material is selected from the group consisting of carbon black, graphite powder, metallized glass fibers, pitch-derived carbon fibers, graphite fibers, polyacrylonitrile-derived carbon fibers and polyacrylonitrile-derived graphite fibers.

Claim 21

The process of any one of claims 14 or 16 wherein the filler material is comprised of a mixture of carbon black and graphite fibres in a range of 10-70 wt % of the total composition.

Claim 22

The process of any one of claims 14 or 16 wherein the elevated pressure is in the range from 25-2500 Kg/cm 2 .

Claim 23

The process of any one of claims 14 or 16 wherein during the elevated pressure step the temperature is in the range 150°-750° C.

Claim 24

A flexible, conducting plastic substrate material for a conducting prepared by the process of claim 14.

Claim 25

A flexible, conducting plastic substrate material for a conducting electrode comprising: (a) a conductive filler material; (b) a thermo-plastic polymer; and (c) an elastomeric polymer; wherein (a) is present in an amount such that the plastic substrate material is electrically conducting and (a), (b), and (c) are each in an amount in a ratio of (a):(b):(c) such that the substrate material is flexible and has high tensile strength.

Claim 26

A flexible, conducting plastic substrate material for a conducting electrode comprising: (a) a conductive filler material; (b) a thermo-plastic polymer; and (c) an elastomeric polymer; wherein (a) is present in an amount such that the plastic substrate material is electrically conducting and (a), (b), and (c) are each in an amount in a ratio of (a):(b):(c) such that the substrate material is flexible and has high tensile strength.

Claim 27

An all-vanadium redox battery having a positive compartment containing a catholyte in electrical contact with a positive electrode, the catholyte comprising an electrolyte containing tetravalent vanadium ions or pentavalenet vanadium ions, a negative compartment containing an anolyte in electrical contact with a negative electrode, the anolyte comprising an electrolyte containing tetravalent vanadium ions, trivalent vanadium ions or divalent vanadium ions, and an ionic conducting separator disposed between the positive and negative compartments and in contact with the catholyte and anolyte to provide ionic communication therebetween and wherein the catholyte includes a salt of the formula (VO(X) y where when y is 2 then X is selected from the group consisting of F, Br and Cl and when y is 1 then X is selected from the group consisting of SO 4 , or O, V 2 O 5 , V 2 O 3 , V 2 O 4 , VO, VSO 4 , VOSO 4 , V 2 (SO 4 ) 3 , (VO 2 ) 2 SO 4 ), and NH 4 VO 3 , and a concentration of the salt is 0.1M to 5.0M, and wherein at least one of the positive and negative electrodes comprises a plastic substrate material of claim 1 or 22 or 23.

Claim 28

A conducting electrode comprising the plastic substrate material of claim 23; and a further electrode component selected from the group consisting of a metal mesh, a metal sheet, a metal foil, and graphite felt, and wherein the further electrode component is pressure and heat welded to the plastic substrate material in a configuration selected from the group consisting of a layer of the further electrode component and a layer of the plastic substrate material, a layer of metal foil between two layers of the plastic substrate material, and a layer of metal mesh between two layers of the plastic substrate material.

Claim 29

The plastic substrate material of claim 23 wherein the conductive filler material is selected from the group consisting of carbon black, graphite, metal powder, metallized glass fibres, pitch-derived carbon fibres, graphite fibres, polyacrylonitrile-derived carbon fibres and polyacrylonitrile-derived graphite fibres.

Claim 30

The plastic substrate material of claim 26 wherein the conductive filler material comprises carbon black in an amount of 10-70 wt % of the total composition.

Claim 31

The plastic substrate material of claim 26 wherein the conductive filler material comprises a mixture of carbon black and graphite fibres in a weight in the range of 5:95 to 95:5 in an amount of 10-70 wt % of the total composition.

Claim 32

The plastic substrate material of claim 28 wherein the black to graphite fibres is in a weight ratio of 50:50.

Claim 33

The plastic substrate material of any one of claims 26 to 29 wherein at least two different types of carbon black are used, namely, fine carbon black powder (2-35 nm) and coarse carbon black powder (35 nm-10,000 nm) in a weight ratio of fine carbon:coarse carbon of from 1:99 to 99:1.

Claim 34

The plastic substrate material of claim 26 wherein the electrode has a weight ratio of carbon black plus graphite fibres content to total polymer of 2:3.

Claim 35

The plastic substrate material of claim 23 wherein the thermo-plastic polymer is 10-80 wt % of the total composition.

Claim 36

The plastic substrate material of claim 23 wherein the thermo-plastic polymer is selected from the group consisting of low density polyethylene, high density polyethylene, polypropylene, polybutylene and polystyrene.

Claim 37

The plastic substrate material of claim 23 wherein the elastomeric polymer includes at least one or more polymers selected from the group consisting of styrene-isoprene-styrene, nitrile rubber (NBR), ethylene-propylene-diene terpolymer (EPDM), ethylene-propylene copolymer EP, styrene-butadiene (SB), ethylene-propylene rubber (EPR), n-butyl rubber, styrene-butadiene-styrene, santoprene, and styrene-(ethylene-butylene)-styrene.

Claim 38

The plastic substrate material of claim 23 or 34 wherein the elastomeric polymer is from 1-50 wt % of the total composition.

Claim 39

A process for making a flexible, conducting plastic substrate material for a conducting electrode, the process comprising: (a) mixing a thermo-plastic polymer, an elastomeric polymer and conductive filler material, the mixing being at a temperature(s) above the melting point temperatures of the thermo-plastic polymer and the elastomeric polymer, (b) extruding or pressure moulding the mixture of (a) at a temperature above the melting temperatures of the thermo-plastic polymer and the elastomeric polymer, and (c) cooling the cross-linked polymerized mixture of (b) to form the substrate material; wherein the conductive filler material is present in an amount such that the substrate material is electrically conducting and the thermo-plastic polymer, elastomeric polymer and conductive filler material are each in an amount such that the substrate material is flexible and has high tensile strength.

Claim 40

A process for making a flexible, conducting plastic substrate material for a conducting electrode, the process comprising: (a) mixing a thermo-plastic polymer, an elastomeric polymer and conductive filler material, the mixing being at a temperature(s) above the melting point temperatures of the thermo-plastic polymer and the elastomeric polymer, (b) extruding or pressure moulding the mixture of (a) at a temperature above the melting temperatures of the thermo-plastic polymer and the elastomeric polymer, and (c) cooling the cross-linked polymerized mixture of (b) to form the substrate material; wherein the conductive filler material is present in an amount such that the substrate material is electrically conducting and the thermo-plastic polymer, elastomeric polymer and conductive filler material are each in an amount such that the substrate material is flexible and has high tensile strength.

Claim 41

The process of claim 36 wherein in step (c) the polymerized mixture of (b) is cooled rapidly.

Claim 42

The process of claim 36 or claim 37 further including the step of pressure and heat welding at least one electrode material selected from the group consisting of a metal mesh, a meal sheet, a metal foil and a graphite felt onto at least one surface of the plastic substrate material.

Claim 43

The process of claim 36 or claim 37 wherein the conductive filler comprises one or more materials selected from the group consisting of carbon black, graphite powder, metal powder, metallized glass fibres, pitch-derived carbon fibres, graphite fibres, polyacrylonitrile-derived carbon fibres and polyacrylonitrile-derived graphite fibres.

Claim 44

The process of claim 36 or claim 37 wherein the conductive filler material comprises a mixture of carbon black and graphite fibres in a range of 10-70 wt % of the total composition.

Claim 45

The process of claim 36 or claim 37 wherein the elevated pressure is in the range from 25-2500 Kg/cm 2 .

Claim 46

The process of claim 36 or claim 37 wherein during the elevated pressure step the temperature is in the range of 150°-750° C.