Lithium secondary battery including a separator

1. A lithium secondary battery comprising

an electrode assembly having two electrodes and a separator interposed between the two electrodes and

a case that contains the electrode assembly,

wherein the separator comprises a binder and a filler including solid electrolyte particles having lithium ion conductivity and a non-ion-conductive ceramic powder,

wherein the solid electrolyte particles and the non-ion-conductive ceramic powder are connected to each other,

wherein a mass ratio of filler to binder in the separator is about 95:5 or greater, and

wherein the binder does not cover entire surfaces of the solid electrolyte particles and the non-ion-conductive ceramic powder, wherein the solid electrolyte particles include at least one composition selected from the group consisting of LiCl—Li 2 O—P 2 O 5 , LiTi 2 (PO 4 ) 3 —AlPO 4 , single-crystal Li 3 N, LiI—Li 2 S—P 2 S 5 , LiI—Li 2 S—B 2 S 3 , LiI—Li 2 S—SiS 4 , Li 2 S—GeS 2 —P 2 S 5 , and La(0.55)-Li(0.35)-TiO 3 , or a combination thereof.

2. The lithium secondary battery according to claim 1 , wherein the solid electrolyte particles are inorganic.

3. The lithium secondary battery according to claim 2 , wherein the inorganic solid electrolyte particles are made of a ceramic material.

4. The lithium secondary battery according to claim 1 , wherein the non-ion-conductive ceramic powder includes at least one material selected from the group consisting of alumina, silica, zirconia, and titania.

5. The lithium secondary battery according to claim 1 ,

wherein the filler comprises secondary particles formed of partially sintered primary particles of the solid electrolyte particles or formed of a partially sintered mixture of primary particles of the solid electrolyte particles and primary particles of the non-ion-conductive ceramic powder.

6. The lithium secondary battery according to claim 5 , wherein the secondary particles are formed by heating the filler to a temperature near the lowest of the melting point of the solid electrolyte particles and the melting point of the non-ion-conductive ceramic powder and applying a necking process.

7. The lithium secondary battery according to claim 1 , wherein the binder of the separator includes an acrylic rubber.

8. The lithium secondary battery according to claim 1 , wherein the binder includes methacrylate.

9. The lithium secondary battery according to claim 1 , wherein the separator is in the form of a separator film integrated with at least one surface of at least one of the electrodes.

10. The lithium secondary battery according to claim 9 , wherein the separator film is porous and wherein pores of the separator film are filled with a liquid or gel electrolyte.

11. The lithium secondary battery according to claim 9 , wherein the separator film is formed by dipping at least one of the electrodes into a separator film solution.

12. The lithium secondary battery according to claim 9 , wherein the separator film is formed on at least one of the electrodes by printing.

13. The lithium secondary battery according to claim 9 , wherein the separator film is formed on one or both of the electrodes by spraying.

14. The lithium secondary battery according to claim 1 , wherein the separator comprises

a first separator film comprising the binder and the filler including the solid electrolyte particles having lithium ion conductivity and the non-ion-conductive ceramic powder, wherein the first separator film is porous and is integrated with at least one surface of at least one of the electrodes, and

a second separator film that comprises a polyolefin-based resin.