LARGE-FORMAT BATTERY ANODES COMPRISING SILICON PARTICLES
Large-scale anodes containing high weight percentages of silicon suitable for use in lithium-ion energy storage devices and batteries, and methods of manufacturing the same, are described. The anode material described herein can include a film cast on a current collector substrate, with the film including a plurality of active material particles and a conductive polymer membrane coated over the active material particles. In some embodiments, the conductive polymer membrane comprises polyacrylonitrile (PAN). The method of manufacturing the anode material can include preparation of a slurry including the active material particles and the conductive polymer material, casting the slurry on a current collector substrate, and subjecting the composite material to drying and heat treatments.
1 .- 15 . (canceled)
16 . An electrode comprising:
a current collector substrate with a surface roughness R z of greater than 1.5 micrometers; and
an electrode film having a thickness of 10 to 80 micrometers disposed over the current collector substrate, wherein the electrode film comprises:
a plurality of active material particles; and
a conductive polymer membrane coating over the active material particles, the conductive polymer membrane coating comprising a thermoplastic polymer treated to become a cyclized, non-plastic ladder compound,
wherein a porosity of the electrode film is between about 50-70%.
17 . The electrode of claim 16 , wherein the porosity of the electrode film is between about 50 to 60%
18 . The electrode of claim 16 , wherein the plurality of active material particles comprise a compound selected from the group consisting of silicon, hard-carbon, graphite, graphene, germanium, titanium oxide, tin, magnesium, antimony, lead, and combinations thereof; and
19 . The electrode of claim 16 , wherein the plurality of active material particles comprise particles selected from the group consisting of silicon particles, a silicon-carbon composite material particles, and combinations thereof.
20 . The electrode of claim 19 , wherein the particles are selected from the group consisting of nano-sphere silicon, nano-wire silicon, nano-rod silicon, whiskers, “coral-shaped” silicon, micro-spherical silicon, silicon-graphite, silicon-graphene, silicon-hard carbon, and combinations thereof.
21 . The electrode of claim 16 , wherein the electrode film comprises 30-60 wt. % silicon.
22 . The electrode of claim 16 , wherein the electrode film comprises at least 60 wt. % silicon.
23 . The electrode of claim 16 , wherein the thermoplastic polymer treated to become a cyclized, non-plastic ladder compound is selected from the group consisting of polyacrylonitrile (PAN), poly (acrylic acid) (PAA), carboxymethyl cellulose (CMC), alginate and combinations thereof; preferably wherein the thermoplastic polymer treated to become a cyclized, non-plastic ladder compound comprises polyacrylonitrile (PAN).
24 . The electrode of claim 16 , wherein a magnitude of an arithmetical mean height Sa of the current collector substrate is less than three times a developed interfacial ratio Sdr of the current collector substrate.
25 . An energy storage device comprising:
a first electrode of claim 16 ;
a second electrode; and
an electrolyte.
26 . The energy storage device of claim 25 , wherein the electrolyte is an imide-based room temperature ionic liquid.
27 . A method of making an electrode comprising:
combining an active material, an additive powder, a polymer powder, and a solvent capable of dissolving the polymer powder to form a slurry, wherein the polymer powder comprises a thermoplastic polymer treated to become a cyclized, non-plastic ladder compound;
casting the slurry over a current collector substrate to form a cast film, wherein the current collector substrate has a surface roughness R z of greater than 1.5 micrometers;
drying the cast film, wherein the cast film has a thickness of 10 to 80 micrometers; and
heat treating the cast film,
wherein the porosity of the dried and heat treated cast film is between 50-70%.
28 . The electrode of claim 27 , wherein the porosity of the dried and heat treated cast film is between about 50 to 60%.
29 . The electrode of claim 27 , wherein the dried and heat treated cast film has a thickness of 10 to 80 micrometers.
30 . The method of claim 27 , wherein the heat treatment comprises applying heat to the cast film at temperatures of 200 to 400° C. for a time of 1 to 12 hours.
31 . The method of claim 27 , wherein the heat treatment is completed under vacuum or in an inert gas flow.
32 . The method of claim 27 , wherein the slurry has a Brookfield viscosity of 2000-6000 cP at 20 to 100 RPM using a #64 spindle, at room temperature.
33 . The method of claim 27 , wherein the thermoplastic polymer treated to become a cyclized, non-plastic ladder compound is selected from the group consisting of polyacrylonitrile (PAN), poly (acrylic acid) (PAA), carboxymethyl cellulose (CMC), alginate and combinations thereof.
34 . The method of claim 27 , wherein the additive powder comprises a material selected from the group consisting of lithium metal powder, lithium nitride, oxalic acid, and combinations thereof.
35 . The method of claim 27 , wherein the solvent is selected from the group consisting of N,N-dimethylformamide (DMF), dimethyl sulfone (DMSO 2 ), dimethyl sulfoxide (DMSO), N-methyl-2-pyrrolidone (NMP), N,N-dimethyl acetamide (DMAc), ethylene carbonate (EC), propylene carbonate (PC), and combinations thereof.
36 . The method of claim 27 , wherein the active material comprises a silicon and a carbonaceous active material.
37 . The method of claim 36 , wherein a weight ratio of silicon:carbonaceous material is 10:90 to 90:10.
38 . The method of claim 27 , wherein the dried and heat treated cast film comprises 30-60 wt. % silicon.
39 . A method of making an energy storage device comprising:
manufacturing a first electrode according to the method of claim 27 ;
disposing the first electrode, a second electrode and an electrolyte within a housing.