Composite polymer electrolyte (CPE) membranes for secondary solid state li-metal cells and process for the production thereof
The present invention relates to a curable composition for preparing a composite polymer electrode, the curable composition containing: A) a Li-ion conducting solid electrolyte whose general composition has the formula: Li 7+x−y M II x M III 3−x M IV 2−y O 12 wherein M II , M III , M IV , M V are species of valence II to V; where 0≤x<3, preferably 0≤x≤2; and 0≤y<2 preferably 0≤y≤1; (B) a polymer; (C) a lithium salt; (D) an active plasticizer; and (E) a photoinitiator. The invention also relates to a process of preparing the curable composition, cured compositions and films derived from the curable composition, and solid-state lithium batteries whose solid electrolyte layer contains a cured composition or a cured film according to the invention.
1. A curable composition for preparing a composite polymer electrolyte, the curable composition containing:
(A) a Li-ion conducting solid electrolyte;
(B) a polymer;
(C) a lithium salt;
(D) an active plasticizer; and
(E) a photoinitiator;
wherein the Li-ion conducting solid electrolyte (A) is lithium-lanthanum-zirconate (LLZO),
wherein the polymer (B) has a polymer chain of the type: polyether, polyacrylonitrile, polycarbonate, polyester, polylactone, poly(meth)acrylate ester; or polymer (B) is a block copolymer containing two or more of such polymer chain types as component blocks in polymer chains; or polymer (B) is a physical blend of two or more of such polymer chain types, and
wherein the active plasticizer (D) is one or more selected from the group consisting of: dimethoxytetraethylene glycol (TEGDME), diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, poly(ethylene glycol) dimethyl ether, and wherein the active plasticizer (D) has a water content below 10 ppm, and/or is obtained via a distillation process and/or via a drying step on molecular sieves and/or via a combination of both a distillation process and a drying step on molecular sieves to ensure its purity.
2. The curable composition according to claim 1 , wherein the polymer (B) is poly(ethylene oxide) (PEO) and/or poly(propylene oxide) (PPO).
3. The curable composition according to claim 1 , wherein the Li-ion salt (C) is one or more selected from the group consisting of: LiPF 6 , LiBF 4 , LiClO 4 , LiFSI, LiTFSI, LiBOB, LiAsF 6 , LiFAP, LiTriflate, LiDMSI, LiHPSI, LiBETI, LiDFOB, LiBFMB, LiBison, LiDCTA, LiTDI, LiPDI.
4. The curable composition according to claim 1 , wherein the active plasticizer (D) has a water content below 5 ppm, and/or is obtained via a distillation process and/or via a drying step on molecular sieves and/or via a combination of both a distillation process and a drying step on molecular sieves to ensure its purity.
5. The curable composition according to claim 1 , wherein the photoinitiator (E) has an aryl-CO— group, and is selected from the group consisting of 4-methylbenzophenone, benzophenone, chlorobenzophenone, fluorenones, xanthones, benzils, anthraquinones, terephthalophenones, an alpha-ketocoumarin, and a terephthalophenone.
6. The process of preparing a composition according to claim 1 comprising the mixing of components (A) to (E) at a temperature not exceeding 100° C.
7. The process of preparing a composition according to claim 1 comprising the mixing of components (A) to (E), with grinding, at a temperature not exceeding 100° C.
8. The process according to claim 6 , carried out a temperature not exceeding 90° C.
9. The process according to claim 6 , carried out a temperature not exceeding 80° C.
10. The process according to claim 6 , wherein no organic solvent is added to the mixture of components (A) to (E).
11. The process according to claim 6 wherein no Room Temperature Ionic Liquid (RTIL) is added to the mixture of components (A) to (E).
12. A film having a composition according to claim 1 .
13. A film according to claim 12 having a thickness of at least 0.5 μm and at most 500 μm.
14. A film according to claim 12 having a thickness of at least 1.0 μm and at most 200 μm.
15. A cured composition obtained by exposure of the curable composition according to claim 1 .
16. A cured film obtained by exposure to UV light of the film according to claim 12 .
17. A solid-state lithium battery comprising the following elements:
a positive electrode active material layer;
a solid electrolyte layer;
a negative electrode active material layer,
wherein the solid electrolyte layer contains a cured composition according to claim 15 , and the solid electrolyte layer is positioned between the positive electrode active material layer and negative electrode active material layer.
18. A solid-state lithium battery comprising the following elements:
a positive electrode active material layer;
a solid electrolyte layer;
a negative electrode active material layer,
wherein the solid electrolyte layer contains a cured composition according to claim 16 , and the solid electrolyte layer is positioned between the positive electrode active material layer and negative electrode active material layer.
19. The solid state lithium battery according to claim 17 , which is assembled in a monopolar or a bipolar configuration.