HIGH GREEN DENSITY CERAMICS FOR BATTERY
Set forth herein are processes and materials for making ceramic thin green tapes by casting ceramic source powders and precursor reactants, binders, and functional additives into unsintered thin green tapes in a non-reactive environment.
1 . A process for making a high density green tape on a substrate, the process comprising:
(a) providing a slurry comprising at least one source powder;
(b) mixing the slurry with a binder solution;
(c) casting the slurry onto the substrate to form a green tape in a non-reactive environment; and
(d) drying the green tape on the substrate in a non-reactive environment to achieve a density of 2.9 g/cm 3 to 5.0 g/cm 3 ;
wherein the at least one source powder is selected from the group consisting of lithium-stuffed garnet, chemical precursors to lithium-stuffed garnet, and lithium-stuffed garnet with aluminum oxide dopants;
wherein the at least one source powder has a particle size distribution d 50 of 100 nm-200 nm, 200 nm-300 nm, 300 nm-400 nm, 400 nm-500 nm, 500 nm-600 nm, 600 nm-700 nm, 700 nm-800 nm, 800 nm-900 nm, 900 nm-1 μm, 1 μm-2 μm, or 2 μm-3 μm; and PCT claim 6 ; and
wherein the non-reactive environment comprises nitrogen gas or argon gas, or a combination thereof, and a dew point at −10° C. to −20° C., at −20° C. to −30° C., at −30° C. to −40° C., at −40° C to −50° C., or at −50° C. to −60° C.
2 . The process of claim 1 , wherein the at least one source powder is calcined in a non-reactive environment to achieve a geometric density greater than 4.7 g/ml.
3 . The process of claim 1 , wherein the amount of the at least one source powder in the green tape is at least 50%, 55%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, or 90% by weight (wt %).
4 . The process of claim 1 , wherein the lithium-stuffed garnet is a material selected from the group consisting of: Li A La B M′ C M″ D Zr E O F , wherein 4<A<8.5, 1.5<B<4, 0≤C≤2, 0≤D≤2; 0≤E<2.5, 10<F≤13.5, and M′ and M″ are each, independently in each instance selected from Al, Mo, W, Nb, Sb, Ca, Ba, Sr, Ce, Hf, Rb, Ga, and Ta.
5 . The process of claim 1 , wherein the process further comprises milling the at least one source powder in an anhydrous aprotic solvent.
6 . The process of claim 5 , wherein aprotic solvent is selected from the group consisting of: benzene, toluene, xylene, ethyl acetate, tetrahydrofuran, dioxane, 1 , 2 - dimethoxyethane , and combinations thereof.
7 . The process of claim 1 , further comprising milling the at least one source powder until the at least one source powder has a particle size distribution d 50 of 100 nm-200 nm, 200 nm-300 nm, 300 nm-400 nm, 400 nm-500 nm, 500 nm-600 nm, 600 nm-700 nm, or 700nm-750 nm.
8 . The process of claim 7 , wherein the milling is selected from the group consisting of dry milling, attrition milling, sonication milling, high energy milling, wet milling, jet milling, and cryogenic milling.
9 . The process of claim 1 , wherein the binder in (b) is selected from the group consisting of polypropylene (PP), atactic polypropylene (aPP), isotactic polypropylene (iPP), ethylene propylene rubber (EPR), ethylene pentene copolymer (EPC), polyisobutylene (PIB), styrene butadiene rubber (SBR), poly(ethylene-co-1-octene) (PE-co-PO), poly(ethylene-co-methylene cyclopentene) (PE-co-PMCP), stereoblock polypropylenes, polypropylene polymethyl pentene, polyethylene oxide (PEO), PEO block copolymers, silicone polymers and copolymers, polyvinyl butyral (PVB), poly(vinyl acetate) (PVAc), polyvinylpyrrolidine (PVP), poly(ethyl methacrylate) (PEMA), acrylic polymers, binders from the Paraloid family of resins, binders from the Butvar family of resins, binders from the Mowital family of resins, and combinations thereof.
10 . The process of claim 1 , further comprising, in (b), milling the slurry, with a dispersant selected from the group consisting of fish oil, fatty acids of degree C 8 -C 20 , alcohols of degree C 8 -C 20 , alkylamines of degree C 8 -C 20 , phosphate esters, phospholipids, polymeric dispersants such as poly(vinylpyridine), poly(ethylene imine), poly(ethylene oxide) and ethers thereof, poly(ethylene glycol) and ethers thereof, polyalkylene amine, polyacrylates, polymethacrylates, poly(vinyl alcohol), poly(vinyl acetate), polyvinyl butyral, maleic anhydride copolymers, glycolic acid ethoxylate lauryl ether, glycolic acid ethoxylate oleyl ether, sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, cetyltrimethylammonium bromide, cetylpyridinium chloride, surfactants and dispersants from the Brij family of surfactants, the Triton family of surfactants, the Solsperse family of dispersants, the SMA family of dispersants, the Tween family of surfactants, and the Span family of surfactants.
11 . The process of claim 10 , wherein the fatty acids of degree C 8 -C 20 are selected from dodecanoic acid, oleic acid, stearic acid, linolenic acid, and/or linoleic acid; or wherein the alcohols of degree C 8 -C 20 are at selected from dodecanol, oleyl alcohol, stearyl alcohol, and combinations thereof; or wherein the alkylamines of degree C 8 -C 20 are selected from dodecylamine, oleylamine, stearylamine, and combinations thereof; or wherein the phospholipids are selected from phosphatidylcholine, lecithin, and combinations thereof.
12 . The process of claim 1 , further comprising, prior to (c) or (d), mixing the slurry of the at least one source powder with a plasticizer selected from dibutyl phthalate, dioctyl phthalate, and benzyl butyl phthalate.
13 . The process of claim 1 , further comprising filtering the at least one source powder, wherein the filtration technique is selected from the group consisting of sieving, centrifugation, and separating particles of different size or different mass.
14 . The process of claim 1 , wherein the slurry on the substrate has a solids loading of 1 wt % to 99 wt % and wherein the solid loading refers to the amount of source powder.
15 . The process of claim 1 , wherein the green tape comprises particles of a lithium-stuffed garnet.
16 . The process of claim 1 , wherein the green tape on the substrate has a density between 2.9 g/cm 3 and 3.2 cm 3 as measured by geometric density.
17 . The process of claim 1 , wherein the green tape on the substrate has a density between 3.0 g/cm 3 and 3.2 g/cm 3 as measured by geometric density.
18 . The process of claim 1 , further comprising sintering the green tape on the substrate.
19 . The process of claim 1 , wherein the mixing and milling steps are in a non-reactive environment.
20 . The process of claim 1 , wherein the substrate is a setter plate selected from platinum (Pt) setter plates, palladium (Pd) setter plates, gold (Au) setter plates, copper (Cu) setter plates, nickel setter plates, aluminum (Al) setter plates, alumina setter plates, porous alumina setter plates, steel setter plates, zirconium (Zr) setter plates, zirconia setter plates, porous zirconia setter plates, lithium oxide setter plates, porous lithium oxide setter plates, lanthanum oxide setter plates, porous lanthanum oxide setter plates, lithium aluminum oxide (LiAlC) setter plates, Lithium zirconium oxide (LhZrOs) setter plates, and combinations thereof.