Electrical insulation layer and battery device

1. An electrical insulation layer having a mesoporous structure and comprising:

microparticles having an average particle diameter of 0.5 μm to 40 μm,

nanoparticles having an average particle diameter of 3 nm to less than 500 nm,

a binder, and

an ion conductive composition;

wherein said microparticles comprise particles of polymethylurea, said nanoparticles comprise particles of aluminum oxide, and said binder comprises lithium polyacrylate.

2. The electrical insulation layer according to claim 1 , wherein the proportion of pores based on the total volume of the electrical insulation layer is 30 to 90 vol %.

3. The electrical insulation layer according to claim 1 , wherein the proportion of mesopores based on the total volume of the electrical insulation layer is 3 to 65 vol %.

4. The electrical insulation layer according to claim 1 , wherein at least one of the microparticles and the nanoparticles has a mesoporous structure.

5. A battery device comprising:

a cathode;

an anode;

an electrical insulation layer of claim 1 , having a mesoporous structure, the electrical insulation layer being arranged between the anode and the cathode; and

an ion conductive composition;

wherein at least one of the microparticles and the nanoparticles has a mesoporous structure.

6. The battery device according to claim 5 , wherein the proportion of pores based on the total volume of the electrical insulation layer is 30 to 90 vol %.

7. The battery device according to claim 5 , wherein the proportion of mesopores based on the total volume of the electrical insulation layer is 3 to 65 vol %.

8. The battery device according to claim 5 , wherein the ion conductive composition comprises a lithium salt and a non-aqueous solvent.

9. The battery device according to claim 8 , wherein the lithium salt comprises an organic acid lithium-boron trifluoride complex represented by general formula (I) or (II) shown below:

[R(COO) n − Li n ]—BF 3n   (I)

[(COO) 2 − Li 2 ]—(BF 3 ) 2   (II)

wherein R represents a hydrocarbon group having a valency of n or a hydride group; and n represents an integer of 1 to 4.

10. The battery device according to claim 9 , wherein the organic acid lithium-boron trifluoride complex comprises at least one member selected from the group consisting of a lithium oxalate-boron trifluoride complex, a lithium succinate-boron trifluoride complex and a lithium formate-boron trifluoride complex.

11. The battery device according to claim 9 , wherein the amount of the organic acid lithium-boron trifluoride complex based on the total amount of the lithium salt is 0.5 mol % or more.

12. The battery device according to claim 8 , wherein the non-aqueous solvent comprises a nitrile solvent.

13. The battery device according to claim 12 , wherein the nitrile solvent comprises at least one member selected from the group consisting of succinonitrile, glutaronitrile and adiponitrile.

14. The battery device according to claim 12 , wherein the amount of the nitrile solvent based on the total amount of the non-aqueous solvent is 50 vol % or more.

15. The battery device according to claim 5 , wherein the microparticles further comprise particles of at least one member selected from the group consisting of melamine formaldehyde resin, lithium polyacrylate, polyamide, poly(lithium 2-acrylamido-2-methylpropanesulfonate), silicon dioxide (SiO 2 ), aluminum oxide (Al 2 O 3 ), pseudoboehmite (AlO(OH)), titanium dioxide (TiO 2 ), zinc oxide (ZnO), potassium fluoride (KF), lithium fluoride (LiF), zeolite and calcium carbonate (CaCO 3 ).

16. The battery device according to claim 5 , wherein the nanoparticles further comprise particles of at least one member selected from the group consisting of silicon dioxide (SiO 2 ), pseudoboehmite (AlO(OH)), niobium oxide (Nb 2 O 5 ), tantalum oxide (Ta 2 O 5 ), titanium dioxide (TiO 2 ), zirconium oxide (ZrO 2 ), tin dioxide (SnO 2 ), zinc oxide (ZnO), potassium fluoride (KF), lithium fluoride (LiF), mesoporous aluminosilicate (Al 2 SiO 5 ), a mesoporous niobium-tantalum composite oxide and a mesoporous magnesium-tantalum composite oxide.

17. The battery device according to claim 5 , wherein the binder further comprises at least one member selected from the group consisting of polyvinyl alcohol, carboxyl group-modified polyvinyl alcohol, polyvinyl pyrrolidone, polyethylene oxide, polypropylene oxide, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyacrylic acid, poly(methyl methacrylate), poly(butyl acrylate), ethyl hydroxyethyl cellulose, styrene-butadiene resin, carboxymethyl cellulose, polyimide, polyacrylonitrile, polyurethane, ethyl-vinyl acetate copolymer and polyester.

18. The battery device according to claim 5 , wherein the electrical insulation layer is formed on a surface of at least the anode or the cathode.