BINDERS, ELECTROLYTES AND SEPARATOR FILMS FOR ENERGY STORAGE AND COLLECTION DEVICES USING DISCRETE CARBON NANOTUBES
In various embodiments an improved binder composition, electrolyte composition and a separator film composition using discrete carbon nanotubes, their methods of production and utility for energy storage and collection devices, like batteries, capacitors and photovoltaics, is described. The binder, electrolyte, or separator composition can further comprise polymers. The discrete carbon nanotubes further comprise at least a portion of the tubes being open ended and/or functionalized. The utility of the binder, electrolyte or separator film composition includes improved capacity, power or durability in energy storage and collection devices. The utility of the electrolyte and or separator film compositions includes improved ion transport in energy storage and collection devices.
1 . A composition for use as a binder material, an electrolyte material or a separator film material of an energy storage or collection device, comprising:
a plurality of discrete carbon nanotube fibers, said fibers having an aspect ratio of from about 10 to about 500, and wherein at least a portion of the discrete carbon nanotube fibers are open ended.
2 . The composition of claim 1 , wherein the portion of discrete carbon nanotubes that are open ended are ion conducting.
3 . The composition of claim 1 , further comprising at least one polymer.
4 . The composition of claim 1 , wherein the carbon nanotubes are further functionalized.
5 . The composition of claim 1 , further comprising at least one dispersion aid.
6 . The composition of claim 3 , wherein the polymer is selected from the group consisting of vinyl polymers, poly(styrene-butadiene), partially or fully hydrogenated poly(styrene butadiene) containing copolymers, functionalized poly(styrene butadiene) copolymers such as carboxylated poly(styrene butadiene), poly(styrene-isoprene), poly(methacrylic acid), poly(methylmethacrylate), poly(acrylic acid), poly(vinylalcohols), poly(vinylacetates), fluorinated polymers, polyvinylpyrrolidone, conductive polymers, polymers derived from natural sources, polyethers, polyesters, polyurethanes, and polyamides; homopolymers, graft, block or random co- or ter-polymers, and mixtures thereof.
7 . The composition of claim 2 , further comprising additional inorganic structures comprising elements of the groups two through fourteen of the Periodic Table of Elements.
8 . The binder composition of claim 2 further comprising non-fiber carbon structures selected from the group consisting of carbon black, graphite, graphene, oxidized graphene, fullerenes, and mixtures thereof.
9 . The composition of claim 8 , further comprising at least a portion of discrete carbon nanotubes interspersed between graphene and/or oxidized graphene plates.
10 . The composition of claim 1 , wherein the binder material has an impedance of less than or equal to about one billion ohm-m.
11 . The composition of claim 1 , where the electrolyte material or separator film has a charge transfer resistance of less than or equal to about 10 million ohm-m.
12 . The composition of claim 1 , wherein the carbon nanotubes are oriented.
13 . The composition of claim 12 , wherein the orientation is accomplished in a sheet, micro-layer, micro-layer with vertical film orientation, film, molding, extrusion, or fiber spinning fabrication method.
14 . The composition of claim 13 , wherein orientation includes post fabrication methods, such as tentering, uniaxial orientation, biaxial orientation and thermoforming.
15 . The composition of claim 1 , wherein a portion of open ended tubes comprise electrolyte.
16 . The composition of claim 15 , wherein the electrolyte comprises a polymer or a liquid.
17 . The composition of claim 1 , wherein 40% to 90% by number of the discrete carbon nanotubes have an aspect ratio of 30-70.
18 . The composition of claim 1 , wherein from 1% to 30% by number of carbon nanotubes have an average aspect ratio 80-140.
19 . An electrode paste for a lead-acid battery comprising:
discrete carbon nanotubes having an average length from about 400 to about 1400 nm; and
polyvinyl alcohol.
20 . A method for making a composition for use as a binder material, an electrolyte material, or a separator film material, comprising the steps of:
a) adding carbon nanotubes to a liquid, solvent or polymer melt;
b) vigorous mixing such as with a sonicator or high shear mixer for a period of time; and
c) continued mixing until a homogenous dispersion is obtained.