Composite solid state electrolyte and lithium ion battery containing the same
A composite solid state electrolyte comprises a polymer electrolyte material, a ceramic ion conductor, and a functionalized coupling agent selected to be compatible with the ceramic ion conductor and the bulk polymer compound. The polymer electrolyte material comprises a bulk polymer compound and a lithium salt. The functionalized coupling agent has a backbone that is structurally similar to the bulk polymer compound.
1. A composite solid state electrolyte comprising:
a polymer electrolyte material comprising a bulk polymer compound and a lithium salt;
a ceramic ion conductor; and
a functionalized coupling agent selected to be compatible with the ceramic ion conductor and the bulk polymer compound, wherein the functionalized coupling agent has a backbone that is structurally similar to the bulk polymer compound.
2. The composite solid state electrolyte of claim 1 , wherein the bulk polymer compound comprises polyethylene oxide (PEO), and the backbone of the functionalized coupling agent comprises polyethylene glycol (PEG).
3. The composite solid state electrolyte of claim 2 , wherein the backbone of the functionalized coupling agent has no less than 8 and no more than 16 repeating units.
4. The composite solid state electrolyte of claim 2 , wherein the backbone of the functionalized coupling agent has no less than 10 and no more than 14 repeating units.
5. The composite solid state electrolyte of claim 2 , wherein the functionalized coupling agent is one of N-(acid-PEG3)-N-bis(PEG3-amine), amino-PEG10-alcohol, amino-PEG10-amine, aminooxy-PEG8-acid, azido-PEG10-acid, Fmoc-N-amido-PEG10-acid), or hydroxy-PEG10-acid.
6. The composite solid state electrolyte of claim 1 , wherein the bulk polymer compound comprises polyvinylidene difluoride (PVDF), and the backbone of the functionalized coupling agent comprises a perfluorinated alkyl.
7. The composite solid state electrolyte of claim 6 , wherein the functionalized coupling agent comprises at least one hydroxyl functional group at an end of the backbone.
8. The composite solid state electrolyte of claim 6 , wherein the functionalized coupling agent is one of 2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoro-1,8-octanediol, heptafluorobutyrylamidine, or 2-(4,4,5,5,6,6,6-heptafluorohexyl)malonic acid.
9. The composite solid state electrolyte of claim 1 , wherein the ceramic ion conductor comprises lithium aluminum titanium phosphate (LATP).
10. The composite solid state electrolyte of claim 1 , wherein the lithium salt comprises lithium triflate.
11. The composite solid state electrolyte of claim 1 , wherein the ceramic ion conductor is present at a concentration of at least 10 weight percent relative to a total weight of the composite solid state electrolyte.
12. The composite solid state electrolyte of claim 1 , wherein the functionalized coupling agent is compatible with each of the bulk polymer compound and the ceramic ion conductor via at least one of a chemical bond or attractive intermolecular forces.
13. A lithium ion battery comprising:
a cathode capable of reversible intercalation of lithium ions;
an anode; and
a composite solid state electrolyte comprising:
a polymer electrolyte material comprising a bulk polymer compound and a lithium salt;
a ceramic ion conductor; and
a functionalized coupling agent selected to be compatible with the ceramic ion conductor and the bulk polymer compound, wherein the functionalized coupling agent has a backbone that is structurally similar to the bulk polymer compound.
14. The lithium ion battery of claim 13 , wherein the ceramic ion conductor comprises lithium aluminum titanium phosphate (LATP).
15. The lithium ion battery of claim 13 , wherein the lithium salt comprises lithium triflate.
16. The lithium ion battery of claim 13 , wherein the bulk polymer compound comprises polyethylene oxide (PEO), and the backbone of the functionalized coupling agent comprises polyethylene glycol (PEG).
17. The lithium ion battery of claim 16 , wherein the backbone of the functionalized coupling agent has no less than 8 and no more than 16 repeating units.
18. The lithium ion battery of claim 13 , wherein the bulk polymer compound comprises polyvinylidene difluoride (PVDF), and the backbone of the functionalized coupling agent comprises a perfluorinated alkyl.
19. The lithium ion battery of claim 18 , wherein the functionalized coupling agent comprises at least one hydroxyl functional group at an end of the backbone.
20. A composite solid state electrolyte comprising:
a polymer electrolyte material comprising a bulk polymer compound and lithium triflate salt, wherein the bulk polymer compound comprises one of polyethylene oxide (PEO) or polyvinylidene difluoride (PVDF);
lithium aluminum titanium phosphate (LATP) as a ceramic ion conductor; and
a functionalized coupling agent selected to be compatible with the ceramic ion conductor and the bulk polymer compound, wherein the functionalized coupling agent has a backbone that comprises polyethylene glycol (PEG) when the bulk polymer compound comprises PEO, and the backbone comprises a perfluorinated alkyl when the bulk polymer compound comprises PVDF.