Lithium ion conductive solid electrolyte and production process thereof

Abstract

A lithium ion conductive solid electrolyte formed by sintering a molding product containing an inorganic powder and having a porosity of 10 vol % or less, which is obtained by preparing a molding product comprising an inorganic powder as a main ingredient and sintering the molding product after pressing and/or sintering the same while pressing, the lithium ion conductive solid electrolyte providing a solid electrolyte having high battery capacity without using a liquid electrolyte, usable stably for a long time and simple and convenient in manufacture and handling also in industrial manufacture in the application use of secondary lithium ion battery or primary lithium battery, a solid electrolyte having good charge/discharge cyclic characteristic in the application use of the secondary lithium ion battery a solid electrolyte with less water permeation and being safe when used for lithium metal-air battery in the application use of primary lithium battery, a manufacturing method of the solid electrolyte, and a secondary lithium ion battery and a primary lithium battery using the solid electrolyte.

Description

Claims

1. A lithium ion conductive solid electrolyte formed by sintering a molding product containing an inorganic powder and having a porosity of 10 vol % or less.

2. A lithium ion conductive solid electrolyte according to claim 1, wherein a composition containing the inorganic powder is press molded and then sintered.

3. A lithium ion conductive solid electrolyte according to claim 1, wherein the molding product is sintered under pressing.

4. A lithium ion conductive solid electrolyte according to any one of claims 1 to 3, wherein the inorganic powder contains 10 vol % or less of particles of 50 μm or more.

5. A lithium ion conductive solid electrolyte according to claim 4, wherein the maximum particle size of the inorganic powder is 15 times or less of the average particle size.

6. A lithium ion conductive solid electrolyte according to claim 4, wherein the average particle size of the inorganic powder is 2 μm or less.

7. A lithium ion conductive solid electrolyte according to claim 4, wherein the lithium ion conductivity of the inorganic powder is 1×10−7 Scm−1 or higher at 25° C.

8. A lithium ion conductive solid electrolyte according to claim 4, wherein the inorganic powder contains lithium, silicon, phosphorus, or titanium.

9. A lithium ion conductive solid electrolyte according to claim 4, wherein the inorganic powder contains crystals of Li1+x+y(Al, Ga)x(Ti, Ge)2-xSiyP3-yO12 in which 0≦x≦1 and 0≦y≦1.

10. A lithium ion conductive solid electrolyte according to claim 9, wherein 50 wt % or more of crystals are contained in the inorganic powder.

11. A lithium ion conductive solid electrolyte according to claim 9 , wherein the crystals are crystals not containing pores or crystal grain boundaries that hinder the ion conduction.

12. A lithium ion conductive solid electrolyte according to claim 4, wherein the inorganic powder is glass ceramics.

13. A lithium ion conductive solid electrolyte according to claim 9, wherein the lithium ion conductive crystals are contained by 50 wt % or more.

14. A lithium ion conductive solid electrolyte according to claim 12, wherein the lithium ion conductive glass ceramics are contained by 80 wt % or more.

15. A lithium ion conductive solid electrolyte according to claim 12, wherein the solid electrolyte contains glass ceramics comprising each of the ingredients, by mol % expression; Li2O: 12 to 18%,Al2O3+Ga2O3: 5 to 10%,TiO2+GeO2: 35 to 45%,SiO2: 1 to 10%, andP2O5: 30 to 40%.

16. A lithium ion conductive solid electrolyte according to claim 4, wherein the inorganic powder is glass.

17. A lithium ion conductive solid electrolyte according to claim 4, wherein the lithium ion conductivity is 1×10−4 Scm−1 or higher at 25° C.

18. A primary lithium battery having a lithium ion conductive solid electrolyte according to claim 4.

19. A secondary lithium ion battery having a lithium ion conductive solid electrolyte according to claim 4.

20. A process for producing a lithium ion conductive solid electrolyte of preparing a molding product using an inorganic powder as a main ingredient, and pressing and then sintering the molding product.

21. A process for producing a lithium ion conductive solid electrolyte of preparing a molding product using an inorganic powder as a main ingredient and sintering the same while pressing.

22. A process for producing a lithium ion conductive solid electrolyte according to claim 20 or 21, wherein the inorganic powder contains 10 vol % or less of particles of 50 μm or larger.

23. A process for producing a lithium ion conductive solid electrolyte according to claim 22, wherein the maximum particle size of the inorganic powder is 15 times or less of the average particle size.

24. A process for producing a lithium ion conductive solid electrolyte according to claim 22, wherein the average particle size of the inorganic power is 2 μm or less.

25. A process for producing a lithium ion conductive solid electrolyte according to claim 22, wherein the lithium ion conductivity of the inorganic powder is 1×10−7 Scm−1 or higher at 25° C.

26. A process for producing a lithium ion conductive solid electrolyte according to claim 22, wherein the inorganic powder contains Li1+x+y(Al, Ga)x(Ti, Ge)2-xSiyP3-yO12 in which 0≦x≦1 and 0≦y≦1.

27. A process for producing a lithium ion conductive solid electrolyte according to claim 26, wherein the crystal is a crystal not containing pores or crystal grain boundaries that hinder the ion conduction.

28. A process for producing a lithium ion conductive solid electrolyte according to claim 22, wherein the inorganic powder is glass ceramics.

29. A process for producing a lithium ion conductive solid electrolyte according to claim 22, wherein the inorganic powder is glass.

30. A process for producing a lithium ion conductive solid electrolyte according to claim 22, wherein the porosity of the molding product before sintering is 60% or less.