# US 2019/0245178 A1 · Lithium-stuffed garnet electrolytes with a reduced surface defect density and methods of making and using the same

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 2019/0245178 A1
- Document ID: US20190245178A1
- Status: Published application
- Kind: A1
- Application number: 16/343,361
- Filed: 2017-10-19
- Published: 2019-08-08
- Earliest claimed: 2016-10-21
- Assignees: QuantumScape Corporation
- Applicants: Quantumscape Corporation
- Inventors: David CAO; Cheng-Chieh CHAO; Zhebo CHEN; Lei CHENG; Niall DONNELLY; Wes Hermann; Tim HOLME; Tommy HUANG; Kian KERMAN; Yang LI; Harsh MAHESHWARI
- Web page: https://patentgrep.com/patent/US20190245178A1

## CPC

- H01M 10/4235: {Safety or regulating additives or arrangements in electrodes, separators or electrolyte (H01M10/4242 takes precedence)}
- C01G 25/006: {Compounds containing zirconium, with or without oxygen or hydrogen, and containing two or more other elements}
- C04B 35/44: based on aluminates
- C04B 35/486: Fine ceramics
- C04B 35/495: based on vanadium, niobium, tantalum, molybdenum or tungsten oxides or solid solutions thereof with other oxides, e.g. vanadates, niobates, tantalates, molybdates or tungstates
- C04B 35/62218: {obtaining ceramic films, e.g. by using temporary supports}
- C04B 35/6455: {Hot isostatic pressing}
- H01M 4/0447: {of complete cells or cells stacks}
- H01M 10/0525: Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
- H01M 10/0562: Solid materials
- H01M 50/431: Inorganic material
- H01M 50/46: Separators, membranes or diaphragms characterised by their combination with electrodes
- H01M 50/489: Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
- C01P 2002/30: Three-dimensional structures
- C01P 2002/72: by d-values or two theta-values, e.g. as X-ray diagram
- C01P 2004/02: obtained by optical microscopy
- C01P 2004/03: obtained by SEM
- C01P 2004/52: highly monodisperse size distribution
- C01P 2004/61: Micrometer sized, i.e. from 1-100 micrometer
- C01P 2006/16: Pore diameter
- C01P 2006/40: Electric properties
- C01P 2006/90: Other properties not specified above
- C04B 2235/3203: Lithium oxide or oxide-forming salts thereof
- C04B 2235/3217: Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina
- C04B 2235/3227: Lanthanum oxide or oxide-forming salts thereof
- C04B 2235/3244: Zirconium oxides, zirconates, hafnium oxides, hafnates, or oxide-forming salts thereof
- C04B 2235/3251: Niobium oxides, niobates, tantalum oxides, tantalates, or oxide-forming salts thereof
- C04B 2235/3255: Niobates or tantalates, e.g. silver niobate
- C04B 2235/3839: Refractory metal carbides
- C04B 2235/443: Nitrates or nitrites
- C04B 2235/5436: micrometer sized, i.e. from 1 to 100 micron
- C04B 2235/5463: Particle size distributions
- C04B 2235/764: Garnet structure A3B2(CO4)3
- C04B 2235/786: Micrometer sized grains, i.e. from 1 to 100 micron
- C04B 2235/963: Surface properties, e.g. surface roughness
- H01M 50/403: Manufacturing processes of separators, membranes or diaphragms
- H01M 50/406: Moulding; Embossing; Cutting
- H01M 50/491: Porosity
- H01M 2300/0071: Oxides
- Y02E 60/10: Energy storage using batteries
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- C01G: COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F (metal hydrides {monoborane, diborane or addition complexes thereof} C01B6/00; salts of oxyacids of halogens C01B11/00; peroxides, salts or peroxyacids C01B15/00; thiosulfates, dithionites, polythionates C01B17/64; compounds containing selenium, or tellurium C01B19/00; binary compounds of nitrogen with metals C01B21/06; azides C01B21/08; {compounds containing nitrogen, other non-metals and metal C01B21/082}; metal amides C01B21/092; nitrites C01B21/50; {compounds of noble gases C01B23/0005}; phosphides C01B25/08; salts of oxyacids of phosphorus C01B25/16; carbides C01B32/90; compounds containing silicon C01B33/00; compounds containing boron C01B35/00; compounds having molecular sieve properties but not having base-exchange properties C01B37/00; compounds having molecular sieve and base-exchange properties, e.g. crystalline zeolites, C01B39/00; cyanides C01C3/08; salts of cyanamide C01C3/16; thiocyanates C01C3/20)
- C04B: LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE {(roofing granules E04D7/005)}; CERAMICS (devitrified glass-ceramics C03C10/00); REFRACTORIES; TREATMENT OF NATURAL STONE
- C01P: INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

The disclosure herein relates to rechargeable batteries and solid electrolytes therefore which include lithium-stuffed garnet oxides, for example, in a thin film, pellet, or monolith format wherein the density of defects at a surface or surfaces of the solid electrolyte is less than the density of defects in the bulk. In certain disclosed embodiments, the solid-state anolyte, electrolyte, and catholyte thin films, separators, and monoliths consist essentially of an oxide that conducts Li+ ions. In some examples, the disclosure herein presents new and useful solid electrolytes for solid-state or partially solid-state batteries. In some examples, the disclosure presents new lithium-stuffed garnet solid electrolytes and rechargeable batteries which include these electrolytes as separators between a cathode and a lithium metal anode.

## Claims

### Claim 1

A separator comprising a lithium-stuffed garnet and having top and bottom surfaces and a bulk therebetween,
wherein either or both of the top or bottom surfaces has a lower surface defect density than does the bulk.

### Claim 2 (depends on 1)

The separator of claim 1, wherein the top or bottom surface has a lower areal surface defect density than does the bulk.

### Claim 3 (depends on 1, 2)

The separator of claim 1 or 2, wherein the ninety-ninth (99th) percentile pore aspect ratio of the pores on the top or bottom surface is less than the ninety-ninth (99th) percentile pore aspect ratio of the pores in the bulk.

### Claim 4 (depends on 1, 2, 3)

The separator of any one of claims 1-3, wherein the ninety-ninth (99th) percentile pore aspect ratio of the pores on the top or bottom surface is less than 10 and greater than 0.1.

### Claim 5 (depends on 4)

The separator of claim 4, wherein the ninety-ninth (99th) percentile pore aspect ratio of the pores on the top or bottom surface is less than 4, less than 4.5, less than 4.0, less than 3.5, less than 3.0, less than 2.5, less than 2.0, less than 1.5, less than 1, or less than 0.5.

### Claim 6 (depends on 1, 2, 3, 4, 5)

The separator of any one of claims 1-5, wherein the top or bottom surface is more dense than the bulk.

### Claim 7 (depends on 1, 2, 3, 4, 5)

The separator of any one of claims 1-5, wherein the top or bottom surface is less crystalline than the bulk.

### Claim 8 (depends on 1, 2, 3, 4, 5)

The separator of any one of claims 1-5, wherein the grain size at the top or bottom surface is larger than the grain size in the bulk.

### Claim 9 (depends on 1, 2, 3, 4, 5, 6, 7, 8)

The separator of any one of claims 1-8, wherein the separator is a thin film.

### Claim 10 (depends on 9)

The separator of claim 9, wherein the thickness between the top and bottom surfaces is between 1 nm and 100 nm.

### Claim 11 (depends on 1)

The separator of claim 1, wherein the defect density is a density of inclusions.

### Claim 12

A thin film lithium-stuffed garnet electrolyte, wherein the thin film is substantially homogenous within x- and y-dimensions; and wherein the thin film is inhomogeneous with respect to the z-dimension.

### Claim 13 (depends on 12)

The thin film of claim 12, wherein the inhomogeneity with respect to the z-dimension is a surface defect density inhomogeneity.

### Claim 14 (depends on 12)

The thin film of claim 12 wherein the inhomogeneity with respect to the z-dimension is a porosity inhomogeneity.

### Claim 15 (depends on 12)

The thin film of claim 12, wherein the inhomogeneity with respect to the z-dimension is a grain size inhomogeneity.

### Claim 16 (depends on 12)

The thin film of claim 12, wherein the inhomogeneity with respect to the z-dimension is an inhomogeneity regarding the ninety-ninth (99th) percentile aspect ratios of the pores on the top or bottom surface as compared to in the bulk.

### Claim 17 (depends on 12)

The thin film of claim 12, wherein the inhomogeneity with respect to the z-dimension is an inhomogeneity regarding the average aspect ratios of the pores.

### Claim 18 (depends on 12)

The thin film of claim 12, wherein the inhomogeneity with respect to the z-dimension is an inhomogeneity regarding the density of the pores.

### Claim 19 (depends on 12)

The thin film of claim 12, wherein the inhomogeneity with respect to the z-dimension is an inhomogeneity regarding the oxygen vacancy concentration.

### Claim 20 (depends on 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 13, 14, 15, 16, 17, 18, 19)

An electrochemical stack comprising the separator of any one of claims 1-10, or the thin film of any one of claims 12-19.

### Claim 21

A process for selectively reducing the number and/or size of surface-pores and defects on a lithium-stuffed garnet separator, the method comprising:
providing a sintered separator comprising a lithium-stuffed garnet;
heating the top and/or bottom surfaces of the separator above the melting temperature; and
rapidly cooling the separator below the melting temperature.

### Claim 22 (depends on 21)

The process of claim 21, further comprising adding lithium-stuffed garnet precursors on the top and/or bottom surface prior to the heating step.

### Claim 23 (depends on 21)

The process of claim 21, wherein the lithium-stuffed garnet precursors are powders

### Claim 24 (depends on 21, 22, 23)

The process of any one of claims 21-23, wherein the heating is for the minimal time period required to melt the top and/or bottom surface.

### Claim 25 (depends on 21, 22, 23, 24)

The process of any one of claims 21-24, wherein the cooling is for the longest time which still provides for smaller grains on the top or bottom surface than in the bulk.

### Claim 26 (depends on 21, 22, 23, 24)

The process of any one of claims 21-24, wherein the cooling is for the longest time which still provides for a top and/or bottom surface which is denser than the bulk.

### Claim 27 (depends on 21, 22, 23, 24)

The process of any one of claims 21-24, wherein the cooling is for the longest time which still provides for a top and/or bottom surface which is less crystalline than the bulk.

### Claim 28 (depends on 21, 22, 23, 24, 25, 26, 27)

The process of any one of claims 21-27, wherein the heating is to 1325° C.

### Claim 29 (depends on 21, 22, 23, 24, 25, 26, 27)

The process of any one of claims 21-27, wherein the heating is to greater than 1325° C.

### Claim 30 (depends on 21, 22, 23, 24, 25, 26, 27)

The process of any one of claims 21-27, wherein the heating is in an inert or reducing atmosphere, wherein the atmosphere H2 and a member selected form the group consisting of He, N2, Ar or a combination thereof.

### Claim 31 (depends on 30)

The process of claim 30, wherein the heating is in argon.

### Claim 32 (depends on 30)

The process of claim 30, wherein the heating is in Ar, Ar/H2O2, N2.

### Claim 33 (depends on 30)

The process of claim 30, wherein the heating is conducted in an oven, with a laser, a Rapid Thermal Processing instrument, (RTP),infrared radiation, UV radiation, or a flash lamp.

### Claim 34 (depends on 30)

The process of claim 30, wherein the lithium-stuffed garnet is calcined lithium-stuffed garnet.

### Claim 35 (depends on 21, 22, 23, 24, 25, 26, 27, 28, 29, 30)

The process of any one of claims 21-30, wherein the lithium-stuffed garnet is a sintered lithium-stuffed garnet.

### Claim 36 (depends on 21, 22, 23, 24, 25, 26, 27, 28, 29, 30)

The process of any one of claims 21-30, the lithium-stuffed garnet is an annealed lithium-stuffed garnet.

### Claim 37 (depends on 21, 22, 23, 24, 25, 26, 27, 28, 29, 30)

The process of any one of claims 21-30, the lithium-stuffed garnet is an annealed lithium-stuffed garnet consisting essentially of lithium-stuffed garnet.

### Claim 38

A process for making a solid electrolyte, comprising
a. providing lithium-stuffed garnet chemical precursors or calcined lithium-stuffed garnet, wherein the lithium-stuffed garnet chemical precursors or calcined lithium-stuffed garnet are provided having a narrow particle size distribution;
b. shaping the lithium-stuffed garnet chemical precursors or calcined lithium-stuffed garnet into a thin film form factor; and
c. sintering the lithium-stuffed garnet chemical precursors or calcined lithium-stuffed garnet using spark plasma sintering (SPS) or hot-press sintering (HPS) to provide a sintered lithium-stuffed garnet thin film.

### Claim 39 (depends on 38)

The method of claim 38, wherein the particle size distribution has a d90 less than 25-45 μm.

### Claim 40 (depends on 38)

The method of claim 38, wherein the particle size distribution has a d90 less than 2-20 μm.

### Claim 41 (depends on 38)

The method of claim 38, wherein the particle size distribution has a d90 of about 2-20 μm.

### Claim 42 (depends on 38, 39, 40, 41)

The method of any one of claims 38 to 41, wherein the sintering is SPS.

### Claim 43 (depends on 38, 39, 40, 41)

The method of any one of claims 38 to 41, wherein the sintering is hot-press sintering.

### Claim 44 (depends on 38, 39, 40, 41, 42, 43)

The method of any one of claims 38 to 43, further comprising polishing the sintered lithium-stuffed garnet thin film.

### Claim 45 (depends on 38, 39, 40, 41, 42, 43)

The method of any one of claims 38 to 43, further comprising cutting the sintered lithium-stuffed garnet thin film so that it has a thickness less than 100 μm.

### Claim 46 (depends on 38, 39, 40, 41, 42, 43, 44, 45)

The method of any one of claims 38 to 45, wherein the sintered lithium-stuffed garnet thin film has a surface roughness of about 20 nm (Ra).

### Claim 47 (depends on 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)

A method of discharging or charging an electrochemical cell comprising the separator of any one of claims 1 to 11, or the thin film of any one of claims 12 to 19, or the electrochemical stack of claim 20, comprising discharging or charging the electrochemical cell:
below a critical current, wherein the critical current is a function of the pore aspect ratio of the defects on the top or bottom surface of the separator or thin film;
above a critical temperature, wherein the critical temperature is a function of the pore aspect ratio of the defects on the top or bottom surface of the separator or thin film; and/or
above a critical pressure, wherein the critical pressure is a function of the pore aspect ratio of the defects on the top or bottom surface of the separator or thin film.

### Claim 48 (depends on 48)

The method of claim 48, comprising cycling the electrochemical cell at 2 mA/cm2 at 22° C.

### Claim 49 (depends on 48)

The method of claim 48, comprising discharging the electrochemical cell at 1 mA/cm2, 300 psi, and 50° C. A process for making a lithium-stuffed garnet powder, comprising
providing ZrO2, LiOH, La2O3 and Al(NO3)3 at a desired stoichiometry and/or with excess lithium to form a mixture;
mixing and rapidly heating to at least 1300° C.;
melting; and atomizing into a cooling environment to form spherical particles of phase pure garnet.