ENERGY STORAGE DEVICES
Disclosed herein is an apparatus comprising an active layer substantially free of binding agents, the active layer comprising a network of carbon nanotubes defining void spaces, the network of carbon nanotubes making up less than 10% by weight of the active layer; and a carbonaceous material located in the void spaces and bound by the network of carbon nanotubes; wherein the active layer is configured to provide energy storage.
1 . An apparatus comprising:
an active layer substantially free of binding agents, the active layer comprising:
a network of carbon nanotubes defining void spaces, the network of carbon nanotubes making up less than 10% by weight of the active layer; and
a carbonaceous material located in the void spaces and bound by the network of carbon nanotubes;
wherein the active layer is configured to provide energy storage.
2 . The apparatus of claim 1 , wherein the active layer consists essentially of the carbonaceous material and the carbon nanotubes.
3 . The apparatus of claim 1 , wherein the active layer is bound together by electrostatic forces between the carbon nanotubes and the carbonaceous material.
4 . The apparatus of claim 1 , wherein the carbonaceous material comprises activated carbon.
5 . The apparatus of claim 1 , wherein the carbonaceous material comprises nanoform carbon other than carbon nanotubes.
6 . The apparatus of claim 1 , wherein the network of carbon nanotubes makes up less than 5% by weight of the active layer.
7 . The apparatus of claim 1 , wherein the network of carbon nanotubes makes up less than 1% by weight of the active layer.
8 . The apparatus of claim 1 , further comprising an adhesion layer consisting essentially of carbon nanotubes disposed between the active layer and an electrically conductive layer.
9 . The apparatus of claim 8 , wherein a surface of the electrically conductive layer facing the adhesion layer comprises a roughened or textured portion.
10 . The apparatus of claim 8 , wherein a surface of the electrically conductive layer facing the adhesion layer comprises a nanostructured portion.
11 . The apparatus of claim 10 , wherein the nanostructured portion comprises carbide nanowhiskers.
12 . The apparatus of claim 1 , wherein the active layer has been annealed to reduce the presence of impurities.
13 . The apparatus of claim 1 , wherein the active layer has been compressed to deform at least a portion of the network of carbon nanotubes and the carbonaceous material.
14 . The apparatus of claim 1 , further comprising an electrode comprising the active layer.
15 . The apparatus of claim 14 , further wherein the electrode is a two-sided electrode comprising a second active layer.
16 . The apparatus of claim 14 , further comprising an ultracapacitor comprising the electrode.
17 . The apparatus of claim 16 , wherein the ultracapacitor has an operating voltage greater than 3.0 V.
18 . The apparatus of claim 16 , wherein the ultracapacitor has an operating voltage greater than 3.2 V.
19 . The apparatus of claim 16 , wherein the ultracapacitor has an operating voltage greater than 3.5 V.
20 . The apparatus of claim 16 , wherein the ultracapacitor has an operating voltage greater than 4.0 V.
21 . The apparatus of claim 16 , wherein the ultracapacitor has a maximum operating temperature of at least 250° C. at an operating voltage of at least 1V for a lifetime of at least 1,000 hours.
22 . The apparatus of claim 16 , wherein the ultracapacitor has a maximum operating temperature of at least 250° C. at an operating voltage of at least 2V for a lifetime of at least 1,000 hours.
23 . The apparatus of claim 16 , wherein the ultracapacitor has a maximum operating temperature of at least 250° C. at an operating voltage of at least 3V for a lifetime of at least 1,000 hours.
24 . The apparatus of claim 16 , wherein the ultracapacitor has a maximum operating temperature of at least 250° C. at an operating voltage of at least 4V for a lifetime of at least 1,000 hours.
25 . The apparatus of claim 16 , wherein the ultracapacitor has a maximum operating temperature of at least 300° C. at an operating voltage of at least 1V for a lifetime of at least 1,000 hours.
26 . The apparatus of claim 16 , wherein the ultracapacitor has a maximum operating temperature of at least 300° C. at an operating voltage of at least 2V for a lifetime of at least 1,000 hours.
27 . The apparatus of claim 16 , wherein the ultracapacitor has a maximum operating temperature of at least 300° C. at an operating voltage of at least 3V for a lifetime of at least 1,000 hours.
28 . The apparatus of claim 16 , wherein the ultracapacitor has a maximum operating temperature of at least 300° C. at an operating voltage of at least 4V for a lifetime of at least 1,000 hours.
29 . A method comprising:
dispersing carbon nanotubes in a solvent to form a dispersion; mixing the dispersion with carbonaceous material to form a slurry; applying the slurry in a layer; and
drying the slurry to substantially remove the solvent to form an active layer that is substantially free of binder material, the active layer comprising a network of carbon nanotubes making up less than 10% by weight of the active layer, the carbon nanotubes defining void spaces and the carbonaceous material is located in the void spaces and bound by the network of carbon nanotubes.
30 . The method of claim 29 , further comprising forming and/or applying a layer of carbon nanotubes to provide an adhesion layer on a conductive layer.
31 . The method of claim 30 , wherein the applying step comprises applying the slurry onto the adhesion layer.