Composite solid electrolytes for lithium batteries

1. A composite solid electrolyte for solid-state lithium batteries, comprising:

a solid polymer;

phyllosilicate nanoparticles distributed in the solid polymer, wherein the phyllosilicate nanoparticles are bilayer phyllosilicates; and

a lithium salt distributed in the solid polymer.

2. The composite solid electrolyte of claim 1 , wherein the solid polymer comprises one or more of polyethylene oxide, polymethyl methacrylate, polycarbonate, polysiloxane, starch, sugar, fiber, polyvinyl alcohol, polyphosphazene and polystyrene.

3. The composite solid electrolyte of claim 2 , wherein a molar ratio of ethylene oxide units to lithium ions (EO:Li) in the composite solid electrolyte is from 8:1 to 25:1.

4. The composite solid electrolyte of claim 1 , wherein the composite solid electrolyte is formed as a thin film having a thickness from 1 μm to 300 μm.

5. The composite solid electrolyte of claim 4 , wherein the thickness is from 10 μm to 100 μm.

6. The composite solid electrolyte of claim 1 , wherein the phyllosilicate nanoparticles are in the form of nanotubes, nanoplatelets, or a combination thereof.

7. The composite solid electrolyte of claim 1 , wherein the phyllosilicate nanoparticles comprise an aluminum based phyllosilicate, a magnesium based phyllosilicate, or a combination thereof.

8. The composite solid electrolyte of claim 1 , wherein the bilayer phyllosilicate nanoparticles comprise one or more of halloysite, kaolinite, chrysotile, and antigorite.

9. The composite solid electrolyte of claim 1 , wherein the phyllosilicate nanoparticles are chemically modified with a lithium ion.

10. The composite solid electrolyte of claim 1 , wherein the phyllosilicate nanoparticles are functionalized by one or more of carbonate, ethylene oxide, and phosphazene.

11. The composite solid electrolyte of claim 1 , wherein the phyllosilicate nanoparticles are in the form of nanotubes having a liquid polymer electrolyte impregnated in an interior volume of the nanotubes.

12. The composite solid electrolyte of claim 1 , wherein the phyllosilicate nanoparticles are bilayer halloysite nanotubes.

13. The composite solid electrolyte of claim 1 , wherein the composite solid electrolyte has a lithium ion conductivity of at least 10 −4 S cm −1 at 25° C.

14. The composite solid electrolyte of claim 1 , wherein the lithium salt is LiTFSI.

15. The composite solid electrolyte of claim 1 , wherein the phyllosilicate nanoparticles are present in an amount from 1 wt % to 30 wt %.

16. A solid state lithium battery cell, comprising:

a composite solid electrolyte layer comprising:

a solid polymer,

phyllosilicate nanoparticles distributed in the solid polymer, wherein the phyllosilicate nanoparticles are bilayer phyllosilicates, and

a lithium salt distributed in the solid polymer;

an anode containing lithium in contact with a first surface of the composite solid electrolyte layer;

a cathode in contact with a second surface of the composite solid electrolyte layer; and

a casing that encloses the solid state lithium battery cell and excludes oxygen from within the solid state lithium battery cell.

17. The solid state lithium battery cell of claim 16 , wherein the cathode comprises sulfur and the anode consists of lithium metal.

18. The solid state lithium battery cell of claim 16 , wherein the solid polymer comprises polyethylene oxide and the phyllosilicate nanoparticles are halloysite nanotubes.

19. The composite solid electrolyte of claim 1 , wherein the solid polymer comprises polyethylene oxide.

20. The solid state lithium battery cell of claim 16 , wherein the solid state lithium battery cell including the solid polymer is a lithium polymer battery.