Garnet materials for Li secondary batteries and methods of making and using garnet materials
Set forth herein are garnet material compositions, e.g., lithium-stuffed garnets and lithium-stuffed garnets doped with alumina, which are suitable for use as electrolytes and catholytes in solid state battery applications. Also set forth herein are lithium-stuffed garnet thin films having fine grains therein. Disclosed herein are novel and inventive methods of making and using lithium-stuffed garnets as catholytes, electrolytes and/or anolytes for all solid state lithium rechargeable batteries. Also disclosed herein are novel electrochemical devices which incorporate these garnet catholytes, electrolytes and/or anolytes. Also set forth herein are methods for preparing novel structures, including dense thin (<50 um) free standing membranes of an ionically conducting material for use as a catholyte, electrolyte, and, or, anolyte, in an electrochemical device, a battery component (positive or negative electrode materials), or a complete solid state electrochemical energy storage device. Also, the methods set forth herein disclose novel sintering techniques, e.g., for heating and/or field assisted (FAST) sintering, for solid state energy storage devices and the components thereof.
1. A method for making a lithium-stuffed garnet thin film, the method comprising:
providing a mixture comprising lithium-stuffed garnet or lithium-stuffed garnet chemical precursors;
providing a slurry comprising the mixture and a solvent;
depositing the slurry onto a substrate to form a film; and
sintering the film between and in direct contact with setter plates to form a lithium-stuffed garnet thin film.
2. The method of claim 1 , wherein the mixture comprises lithium-stuffed garnet chemical precursors and wherein the lithium-stuffed garnet chemical precursors comprise one or more members selected from the group consisting of LiOH, Li 2 O, ZrO 2 , La 2 O 3 , Al 2 O 3 , AlNO 3 , Nb 2 O 5 , Ta 2 O 5 , Li 2 CO 3 , AlNO 3 -hydrate, AlNO 3 .9H 2 O, and combinations thereof.
3. The method of claim 1 , further comprising depositing an additional layer of the slurry onto the lithium-stuffed garnet film to form a multilayer before sintering the thin film between setter plates to form a sintered lithium-stuffed garnet thin film.
4. The method of claim 1 , wherein the substrate comprises a metal selected from the group consisting of Al, Ni, Cu, Au, Ag, Fe, steel, stainless steel, Li, alloys thereof, and combinations thereof.
5. The method of claim 1 , further comprising applying pressure to the film prior to, or concurrent with, sintering the film.
6. The method of claim 1 , comprising the step of depositing the slurry onto a substrate to form a film and subsequently evaporating the solvent prior to sintering the film.
7. The method of claim 1 , wherein the mixture further comprises a member selected from the group consisting of NASICON, LISICON, and a tungsten bronze.
8. The method of claim 1 , wherein the mixture further comprises a binder selected from the group consisting of polypropylene (PP), polyvinyl butyral (PVB), polyvinyl pyrrolidone (PVP), atactic polypropylene (aPP), isotactive polypropylene ethylene propylene rubber (EPR), ethylene pentene copolymer (EPC), polyisobutylene (PIB), ZEON™, styrene butadiene rubber (SBR), polyolefins, polyethylene-co-poly-1-octene (PE-co-PO), PE-co-poly(methylene cyclopentane) (PE-co-PMCP), stereoblock polypropylenes, polypropylene polymethylpentene copolymer and silicone.
9. The method of claim 1 , further comprising a thermal treatment step to remove the binder.
10. The method of claim 1 , wherein depositing comprises tape casting or slot-die coating.
11. The method of claim 1 , comprising sintering the film at 1000° C. to 1200° C. for about 15 minutes to about 2 hours.
12. The method of claim 1 , comprising sintering the film at about 1100° C. for about 15 minutes to about 2 hours.
13. The method of claim 1 , comprising calcining the film at a temperature from about 300° C. to about 1000° C. prior to sintering the film.
14. The method of claim 11 , comprising calcining the film prior to sintering the film at a temperature from about 300° C. to about 1000° C.
15. The method of claim 11 , wherein the temperature is 1075 to 1150° C.
16. A lithium-stuffed garnet film prepared by the method of claim 1 .