Solid electrolyte compositions

1. A battery, comprising:

an anode;

a cathode comprising a lithium-containing electrode active material having a spinel structure or a layered oxide structure; and

an electrolyte film including a lithium salt and a polymer soft-solid material, the polymer soft-solid material comprising a solvent selected from the group consisting of butylene carbonate, butyl sulfoxide, N-methyl-2-pyrrolidone, and γ-caprolactone and comprising an ethylene oxide polymer at a concentration of at least 15% of the total weight of the electrolyte film.

2. The battery of claim 1 , wherein the solvent comprises butylene carbonate.

3. The battery of claim 1 , wherein the solvent comprises butyl sulfoxide.

4. The battery of claim 1 , wherein the solvent comprises N-methyl-2-pyrrolidone.

5. The battery of claim 1 , wherein the solvent comprises γ-caprolactone.

6. The battery of claim 2 , wherein the lithium salt comprises lithium bis(trifluoromethanesulfonyl)imide.

7. The battery of claim 1 , wherein the solvent comprises butylene carbonate and about 20 molar percent lithium bis(trifluoromethanesulfonyl)imide.

8. The battery of claim 4 , wherein the lithium salt comprises lithium bis(trifluoromethanesulfonyl)imide.

9. The battery of claim 1 , wherein the solvent comprises N-methyl-2-pyrrolidone and about 20 molar percent lithium bis(trifluoromethanesulfonyl)imide.

10. The battery of claim 2 , wherein the lithium salt comprises lithium tetrafluoroborate.

11. The battery of claim 1 , wherein the solvent comprises butylene carbonate and about 20 molar percent lithium tetrafluoroborate.

12. The battery of claim 3 , wherein the lithium salt comprises lithium tetrafluoroborate.

13. The battery of claim 1 , wherein the solvent comprises butyl sulfoxide and about 20 molar percent lithium tetrafluoroborate.