Gel polymer electrolytes for batteries
Nanostructured gel polymer electrolytes that have both high ionic conductivity and high mechanical strength are disclosed. The electrolytes have at least two domains—one domain contains an ionically-conductive gel polymer and the other domain contains a rigid polymer that provides structure for the electrolyte. The domains are formed by block copolymers. The first block provides a polymer matrix that may or may not be conductive on by itself, but that can soak up a liquid electrolyte, thereby making a gel. An exemplary nanostructured gel polymer electrolyte has an ionic conductivity of at least 1×10 −4 S cm −1 at 25° C.
1. A nanostructured electrolyte material comprising:
a lamellar structure comprising:
a first domain comprising an ionically-conductive polymer gel phase, the first domain forming a conductive portion of the electrolyte material; and
a second domain adjacent the first domain, the second domain comprising a structural polymer phase, the structural polymer phase having a bulk modulus greater than 10 6 Pa at 25° C., the second domain forming a structural portion of the electrolyte material;
wherein the ionically-conductive polymer gel phase comprises a polymer matrix and a liquid electrolyte that contains one or more solvents and a salt;
wherein the electrolyte material has an ionic conductivity of at least 1×10 −4 Scm −1 at 25° C.
2. The electrolyte material of claim 1 wherein the polymer gel phase comprises a liquid electrolyte that comprises one or more solvents.
3. The electrolyte material of claim 2 wherein the solvent comprises one or more polar additives selected from the group consisting of substituted ethers, substituted amines, substituted amides, substituted phosphazenes, substituted PEGs, alkyl carbonates, nitriles, boranes, and lactones.
4. The electrolyte material of claim 3 wherein the solvent comprises one or more room-temperature ionic liquids.
5. The electrolyte material of claim 3 wherein the solvent comprises one or more Lewis acids.
6. The electrolyte material of claim 3 wherein the solvent comprises one or more high dielectric organic plasticizers.
7. The electrolyte material of claim 3 wherein the structural polymer phase swells less than 5% in the presence of the liquid electrolyte.
8. The electrolyte material of claim 1 wherein the structural polymer phase has a bulk modulus greater than 1×10 6 Pa at 90° C.
9. The electrolyte material of claim 1 wherein the electrolyte material is non-fluorinated.
10. The electrolyte material of claim 1 , wherein the electrolyte material has no cross-linking.
11. The electrolyte material of claim 1 wherein the electrolyte material has an ionic conductivity of at least 1×10 −3 S cm −1 at 25 ° C.
12. The electrolyte material of claim 1 wherein the electrolyte material comprises a plurality of block copolymers, the first domain comprises a plurality of first ionically-conductive polymer blocks, and the second domain comprises a plurality of second structural polymer blocks.
13. The electrolyte material of claim 12 wherein the first polymer blocks comprise one or more polymers selected from the group consisting of polyethers, linear copolymers, polyamines polyethylene oxide, linear polyethers, linear polyacronitriles, linear polyvinylalcohols, and linear polyacrylates.
14. The electrolyte material of claim 12 wherein the first polymer blocks comprise one or more comb polymers that have low glass-transition temperature backbones selected from the group consisting polysiloxane, polyphosphazene, polyether, polyethylene, and polyacrylate.
15. The electrolyte material of claim 12 wherein the first polymer blocks comprise one or more comb polymers that have pendants selected from the group consisting of substituted polyethylene glycols, such as PEG-dimethyl ether, PEG-EC, and PEG-CN.
16. The electrolyte material of claim 12 wherein the second polymer blocks comprise one or more components selected from the group consisting of polystyrene, polymethacrylate, polyvinylpyridine, polyvinylcyclohexane, polyimide, polyamide, polypropylene, and copolymers thereof.
17. A battery cell, comprising:
a positive electrode;
a negative electrode; and
a nanostructured gel polymer electrolyte positioned to provide ionic communication between the positive electrode and the negative electrode;
wherein the nanostructured gel polymer electrolyte comprises:
a lamellar structure comprising:
a first domain comprising an ionically-conductive polymer gel phase, the first domain forming a conductive portion of the electrolyte material; and
a second domain adjacent the first domain, the second domain comprising a structural polymer phase, the structural polymer phase having a bulk modulus greater than 10 6 Pa at 25° C., the second domain forming a structural portion of the electrolyte material;
wherein the ionically-conductive polymer gel phase comprises a polymer matrix and a liquid electrolyte that contains one or more solvents and a salt;
wherein the electrolyte material has an ionic conductivity of at least 1×10 −4 Scm −1 at 25° C.
18. The battery cell of claim 17 wherein the first domain comprises polyethylene oxide.
19. The battery cell of claim 17 wherein the second domain comprises polystyrene.
20. The battery cell of claim 17 , further comprising a third domain comprising a third phase.
21. The battery cell of claim 17 wherein the negative electrode comprises lithium metal.