ELECTRODES FOR ENERGY STORAGE DEVICES
Disclosed herein is an apparatus comprising an electrode active layer comprising a network of high aspect ratio carbon elements defining void spaces within the network; a plurality of electrode active material particles disposed in the void spaces within the network and enmeshed in the network; and a surface treatment on the surface of the high aspect ratio carbon elements which promotes adhesion between the high aspect ratio carbon elements and the active material particles.
1 . An energy storage device comprising an electrode comprising:
an active layer comprising an active material and a nanocarbon, wherein the active layer is substantially free of polyvinylidene fluoride/difluoride (PVDF) and N-methyl-2-pyrrolidone (NMP); and
a current collector.
2 . The energy storage device of claim 1 , wherein the nanocarbon has a high aspect ratio.
3 . The energy storage device of claim 1 , wherein the nanocarbon is selected from the group consisting of carbon nanotubes, graphene, oxidized graphene, exfoliated graphite nano-platelets, carbon nanoparticles, carbon powder, activated carbon, carbon black, carbon nanofibers, carbon nanohorns, carbon nano-onions, fullerene, carbon aerogels, and combinations thereof.
4 . The energy storage device of claim 3 , wherein the nanocarbon comprises carbon nanotubes.
5 . The energy storage device of claim 1 , wherein the nanocarbon has a surface treatment which enhances adhesion of the nanocarbon to the active material and adhesion of the active layer to the current collector.
6 . The energy storage device of claim 1 , wherein the active layer further comprises a polymer additive, a polymer or a surfactant, or any combination thereof.
7 . The energy storage device of claim 1 , wherein the electrode is a cathode, and the active material comprises lithium iron phosphate, a lithium cobalt oxide, a lithium manganese oxide, a lithium nickel manganese oxide, a lithium nickel manganese cobalt oxide, a lithium nickel cobalt aluminum oxide or a lithium titanate oxide.
8 . The energy storage device of claim 7 , wherein the active material comprises a nickel-rich lithium nickel manganese cobalt oxide.
9 . The energy storage device of claim 8 , wherein the active layer of the cathode comprises by weight about 90-99% of a nickel-rich lithium nickel manganese cobalt oxide; about 0.5-5% of the nanocarbon; and about 0.5-5% of a polymer additive, a polymer or a surfactant, or any combination thereof.
10 . The energy storage device of claim 1 , wherein the electrode is a cathode, and the current collector comprises an aluminum foil.
11 . The energy storage device of claim 1 , wherein the electrode is an anode, and the active material comprises silicon, a silicon oxide, a silicon composite material or graphite, or any combination thereof.
12 . The energy storage device of claim 11 , wherein the active material comprises silicon as the dominant element by weight.
13 . The energy storage device of claim 12 , wherein the active layer of the anode comprises by weight about 60-90% of silicon or/and a silicon composite material; about 5-20% of graphite; about 1-5% of the nanocarbon; and about 5-20% of a polymer additive, a polymer or a surfactant, or any combination thereof.
14 . The energy storage device of claim 1 , wherein the electrode is an anode, and the current collector comprises a copper foil.
15 . The energy storage device of claim 1 , further comprising an electrolyte comprising one or more lithium salts and one or more carbonate solvents.
16 . The energy storage device of claim 15 , wherein the electrolyte comprises LiPF 6 or/and lithium bis(fluorosulfonyl)imide (LiFSI), and one or more linear carbonate solvents.
17 . The energy storage device of claim 15 , wherein the electrolyte further comprises one or more additives.
18 . The energy storage device of claim 17 , wherein the one or more additives comprise one or more cyclic carbonates.
19 . The energy storage device of claim 1 , which:
(a) has a specific energy of at least about 330 Wh/kg;
(b) has a gravimetric energy density of at least about 330 Wh/kg;
(c) has a volumetric energy density of at least about 850 Wh/L;
(d) has a capacity of at least about 50 Ah;
(e) has an internal resistance of no more than about 40 mΩ;
(f) charges to 80% stage of charge within about 15 minutes;
(g) has an operating voltage range of at least about 4.0-2.5 V; or
(h) has a cycle life of at least about 750 charge/discharge cycles; or
(i) any combination or all of the above.
20 . The energy storage device of claim 1 , which is a battery cell or a battery.