SINTERING LARGE AREA CERAMIC FILMS
Set forth herein are processes and materials for sintering dense thin green films comprising lithium-stuffed garnet powder and a binder to obtain sintered lithium-stuffed garnet thin films. Some of the processes, herein, include providing a first setter and a second setter, wherein the first setter and second setter each include at least 5 atomic % lithium (Li) per setter; placing the green film on the first setter; placing the second setter within 2 cm of the green film but not in contact with the green film; and heating the green film to at least 900 C.
1 . A process for making a sintered lithium-stuffed garnet thin film, comprising:
(a) providing a green film comprising lithium-stuffed garnet powder;
(b) providing a first setter and a second setter, wherein the first setter and second setter each comprise at least 5 atomic % lithium (Li) per setter;
(c) placing the green film on the first setter;
(d) placing the second setter within 2 cm of the green film but not in contact with the green film; and
(e) heating the green film to at least 900° C.
2 . The process of claim 1 , wherein the green film comprises a binder.
3 . The process of claim 1 - 2 , wherein the green film has a density greater than 2 g/cm 3 as measured by geometric density
4 . The process of any one of claims 1 - 3 , wherein prior to step (a), the process comprises providing a slurry comprising lithium-stuffed garnet powder and a binder.
5 . The process of any one of claims 1 - 4 , wherein in step (d), the second setter is substantially parallel to the first setter.
6 . The process of any one of claims 1 - 5 , wherein the average distance between top surface of the bottom setter and the bottom surface of the top setter is about 10 μm-1 mm.
7 . The process of claim 6 , wherein the top surface of the first setter is the surface of the first setter in direct contact with the green film.
8 . The process of any one of claims 1 - 7 , wherein the first setter or the second setter comprise, or both the first setter and the second setter comprise, at least 5 atomic % Li per setter.
9 . The process of any one of claims 1 - 8 , wherein the thickness of the green film is 10 μm to 500 μm.
10 . The process of any one of claims 1 - 9 , wherein the lithium-stuffed garnet powder in the green film is selected from lithium-stuffed garnet oxide characterized by the formula Li u La v Zr x O y .zAl 2 O 3 , wherein
u is a rational number from 4 to 8;
v is a rational number from 2 to 4;
x is a rational number from 1 to 3;
y is a rational number from 10 to 14; and
z is a rational number from 0.05 to 1;
wherein u, v, x, y, and z are selected so that the lithium-stuffed garnet oxide is charge neutral.
11 . The process of any one of claims 1 - 9 , wherein the lithium-stuffed garnet powder in the green film is selected from Li x La y Zr z O t .qAl 2 O 3 , wherein 4<x<10, 2<y<4, 1<z<3, 10<t<14, and 0≤q≤1.
12 . The process of any one of claims 1 - 11 , wherein the lithium-stuffed garnet powder in the green film is doped with a member selected from the group consisting of Nb, Ga, Ta, and combinations thereof.
13 . The process of any one of claims 1 - 12 , wherein a layer is placed between the green film and the second setter, wherein the layer comprises a metal powder.
14 . The process of any one of claims 1 - 13 , wherein the first setter or second setter comprises lithium-stuffed garnet powder.
15 . The process of any one of claims 1 - 13 , wherein the first setter or the second setter has, or both the first and the second setter have, a surface roughness from 1.0 μm R a to 4 μm R a , wherein R a is an arithmetic average of absolute values of sampled surface roughness amplitudes.
16 . The process of any one of claims 1 - 14 , wherein the green film has a surface defined by a first lateral dimension from 1 cm to 50 cm and a second lateral dimension from 0.001 cm to 50 cm.
17 . The process of any one of claims 1 - 15 , wherein the slurry comprises a solvent.
18 . The process of any one of claims 1 - 16 , comprising placing the second setter within 2 μm of the green film but not in contact with the green film.
19 . The process of any one of claims 1 - 17 , wherein the first setter has a surface defined by a first lateral dimension from 1 cm to 100 cm and a second lateral dimension from 0.001 cm to 100 cm.
20 . The process of any one of claims 1 - 19 , comprising using the first setter or second setter, or both, in at least two sintering processes.
21 . The process of any one of claims 1 - 19 , comprising using the first setter or second setter, or both, in at least five sintering processes.
22 . A process for making a sintered lithium-stuffed garnet thin film, wherein the method comprises:
(a) providing a green film comprising lithium-stuffed garnet powder and a binder;
(b) providing a first setter and a second setter, wherein the first setter and second setter each comprise at least 5 atomic % lithium (Li) per setter;
(c) placing the green film between and in contact with the first setter and the second setter;
(d) losing contact between the green film and the second setter, wherein the second setter is within 2 cm of the green film but not in contact with the green film; and
(e) heating the green film to at least 900° C.
23 . The process of claim 22 , wherein step (c) occurs until the binder is removed by combustion, evaporation, or a combination thereof.
24 . A sintered lithium-stuffed garnet thin film made by any one of the methods in claims 1 - 23 .
25 . The sintered lithium-stuffed garnet thin film of claim 24 , having a surface flatness of less than 500, 450, 400, 350, 300, 250, 200, 150, 100, 50, 40, 30, 20 or 10 μm.
26 . An electrochemical cell or rechargeable battery comprising the sintered lithium-stuffed garnet thin film of claim 24 or 25 .
27 . A sintered lithium-stuffed garnet thin film made by any one of the processes in claims 1 - 23 .
28 . An electrochemical cell or rechargeable battery comprising the sintered lithium-stuffed garnet thin film of any one of claim 24 , 25 , or 27 .
29 . An apparatus comprising
a bottom setter;
a top setter; and
a green film between the bottom setter and the top setter;
wherein the green film contacts the bottom setter but does not contact the top setter.
30 . The apparatus of claim 29 , wherein the distance between the green film and the top setter is at least 2 μm.
31 . The apparatus of claim 29 , wherein the distance between the bottom setter and the top setter is at least 2 cm.
32 . The apparatus of claim 30 or 31 , wherein the distance between the bottom setter and the top setter is no greater than 100 cm.
33 . The apparatus of any one of claims 29 - 32 , comprising spacers between the bottom setter and the top setter.
34 . The apparatus of claim 33 , wherein each spacers is equally spaced from each other spacer.
35 . The apparatus of claim 33 or 34 , wherein the bottom setter is square shaped and the spacers are placed at the corners of the bottom setter.
36 . The apparatus of claim 33 or 34 , wherein the bottom setter is rectangular shaped and the spacers are placed at the corners of the bottom setter.