Composite separator and electrolyte for electrochemical cells
Separator and electrolyte composites include a porous self-supporting separator film between or adjacent one or two electrolyte films. The electrolyte films may contain a glyme or mixture of glymes, LiX salt and complexing agent, such as PEO. The porous self-supporting separator film may be used dry or wetted with a liquid electrolyte composition. Solid state batteries and electrochemical cells are disclosed that include the described separator and electrolyte composites in combination with an anode and a cathode.
1. An electrochemical cell comprising:
a first electrolyte complex comprising:
a glyme in an amount of 18 to 54 weight percent based on total weight of glyme and lithium salt;
a lithium salt in an amount of 46 to 82 weight percent based on total weight of glyme and lithium salt, and
a polymeric complexing agent in an amount of 5 to 50 percent by weight of combined glyme, lithium salt, and polymeric complexing agent;
an anode;
a cathode;
a separator film having a first major surface and a second major surface; and
an electrolyte film contacting the first major surface of the separator film, the electrolyte film comprising the first electrolyte complex.
2. The electrochemical cell of claim 1 , wherein the lithium salt is present at a concentration of 46 to 63 weight percent based on total weight of the electrolyte film.
3. The electrochemical cell of claim 1 , wherein the separator film is saturated with the first electrolyte complex.
4. The electrochemical cell of claim 1 , wherein the anode comprises the first electrolyte complex.
5. The electrochemical cell of claim 1 , wherein the anode comprises lithium metal, lithium alloy, graphitic carbon, petroleum coke, MCMB, lithium titanate, or a combination thereof.
6. The electrochemical cell of claim 1 , wherein the cathode comprises the first electrolyte complex.
7. The electrochemical cell of claim 1 , wherein the cathode comprises silver vanadium oxide, carbon monofluoride, manganese oxide, carbon monofluoride, lithium cobalt oxide, lithium manganese oxide, lithium nickel manganese cobalt oxide, lithium nickel oxide, lithium nickel cobalt aluminum oxide, lithium sulfide, or a combination thereof.
8. The electrochemical cell of claim 1 , wherein the electrolyte film has low volatility.
9. The electrochemical cell of claim 1 , wherein the electrolyte film has a storage modulus of 20 kPa to 1000 kPa at 1 Hz and 37° C.
10. The electrochemical cell of claim 1 , wherein the electrochemical cell is non-hermetically sealed.
11. The electrochemical cell of claim 1 , wherein the lithium salt comprises lithium bis(trifluoromethylsulfonyl) imide (LiTFSI), lithium bis(pentafluoroethylsulfonyl) imide (LiBETI), lithium tris(trifluorosulfonyl) methide, lithium perchlorate (LiClO 4 ), lithium tetrafluoroborate (LiBF 4 ), lithium hexafluoroarsenate (LiAsF 6 ), lithium hexafluorophosphate (LiPF 6 ), or a combination thereof.
12. The electrochemical cell of claim 1 , wherein the glyme comprises tetraethylene glycol dimethyl ether (TEGDME), triethylene glycol dimethyl ether (Triglyme), poly(ethylene glycol dimethyl ether) (PEGDME), poly(ethylene glycol), polyglycol methyl ether, ethylene glycol dibutyl ether, or a combination thereof.
13. The electrochemical cell of claim 1 , wherein the polymeric complexing agent comprises PEO.
14. The electrochemical cell of claim 13 , wherein the polymeric complexing agent is present in an amount of 10 to 30 percent by weight of the combined glyme, lithium salt, and polymeric complexing agent.
15. The electrochemical cell of claim 1 , wherein the electrolyte film is non-aqueous.
16. The electrochemical cell of claim 1 , wherein the separator film is porous and has a pore size of 0.015 micrometers to 1 micrometer.
17. The electrochemical cell of claim 1 , wherein the lithium salt is lithium bis(trifluoromethylsulfonyl) imide (LiTFSI).
18. The electrochemical cell of claim 1 , wherein the glyme is tetraethylene glycol dimethyl ether.
19. The electrochemical cell of claim 1 , wherein the first electrolyte complex is a gel.
20. The electrochemical cell of claim 1 , wherein the cathode comprises a second electrolyte complex different from the first electrolyte complex, the second electrolyte complex comprising:
a glyme;
a lithium salt, and
a polymeric complexing agent.