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CN-121986384-A - Sodium ion conductive glass ceramic

CN121986384ACN 121986384 ACN121986384 ACN 121986384ACN-121986384-A

Abstract

The invention provides a sodium ion conductive glass ceramic which has compact structure, high water resistance and high sodium ion conductivity, and can be used for an electrolyte separator for an aqueous sodium ion secondary battery. The above-mentioned problems are solved by a sodium ion conductive glass ceramic which contains, in mol% based on oxide, 20.0 to 27.0% of Na 2 O component, 30.0 to 40.0% of ZrO 2 component, 3.0 to 20.0% of P 2 O 5 component and 20.0 to 40.0% of SiO 2 component, and contains a monoclinic crystal phase represented by Na 1＋x Zr 2 Si x P 3－x O 12 (0 < X < 3), wherein the proportion of ZrO 2 crystal phase in the entire crystal phases contained is 10 mass% or less.

Inventors

  • OGASA KAZUHITO

Assignees

  • 株式会社小原

Dates

Publication Date
20260505
Application Date
20240918
Priority Date
20231018

Claims (9)

  1. 1. A sodium ion conductive glass ceramic, wherein, In mol% in terms of oxide, contains: 20.0% -27.0% of Na 2 O component; 30.0% -40.0% of ZrO 2 component; 3.0 to 20.0 percent of P 2 O 5 component and 20.0 To 40.0 percent of SiO 2 component, and A crystal phase comprising monoclinic crystals represented by Na 1＋x Zr 2 Si x P 3－x O 12 (0 < x < 3), and the proportion of ZrO 2 crystal phase in the total crystal phase comprised is 10 mass% or less.
  2. 2. The sodium ion conductive glass ceramic according to claim 1, wherein the composition ratio of Na, zr, P and Si in the sodium ion conductive glass ceramic satisfies the composition ratio represented by Na 1＋x Zr 2 Si x P 3－x O 12 (0 < x < 3).
  3. 3. The sodium ion conductive glass ceramic according to claim 1, wherein when the sodium ion conductive glass ceramic is formed into a sheet-like or plate-like substrate, a seepage rate per unit area of the substrate and per 1mm thickness is 10.0. Mu.L/h or less, or when water seepage per unit area of the substrate and per 1mm thickness occurs due to water seepage of the substrate, an amount of current at this time is 15. Mu.A or less per unit area of the substrate and per 1mm thickness.
  4. 4. The sodium ion conductive glass ceramic according to claim 1 or 2, wherein the sodium ion conductivity at 25 ℃ is 6.0 x 10 －4 S/cm or more.
  5. 5. The sodium ion conductive glass ceramic according to claim 1 or2, which is obtained by mixing and sintering a glass material powder having a sodium ion conductivity of 1.0X10 －6 S/cm or less at 25 ℃ and a crystalline material powder having a sodium ion conductivity of less than 1.0X10 －8 S/cm at 25 ℃ and containing a ZrO 2 component.
  6. 6. The sodium ion conductive glass ceramic according to claim 1 or 2, wherein a proportion of a monoclinic crystal phase represented by Na 1＋x Zr 2 SixP 3－x O 12 (0 < x < 3) among all crystal phases included is 70 mass% or more.
  7. 7. The sodium ion conductive glass ceramic according to claim 1 or 2, wherein the proportion of the amorphous phase is 10 mass% or more.
  8. 8. An electrolyte separator for an aqueous sodium ion secondary battery, comprising the sodium ion-conductive glass ceramic according to claim 1 or 2.
  9. 9. A glass material for synthesizing sodium ion conductive glass ceramic, wherein, In mol% in terms of oxide, contains: 30.0 to 40.0 percent of Na 2 O component, 0% -5.0% Of ZrO 2 component, 5.0 To 35.0 percent of P 2 O 5 component, and 30.0 To 60.0 percent of SiO 2 component, and The composition ratio of Na, P and Si satisfies the composition ratio after Zr removal among the composition ratios represented by Na 1＋x Zr 2 SixP 3－x O 12 (0 < X < 3).

Description

Sodium ion conductive glass ceramic Technical Field The present invention relates to a sodium ion conductive glass ceramic, an electrolyte separator for an aqueous sodium ion secondary battery comprising the same, and a glass material for synthesizing the same. Background Conventionally, lithium ion secondary batteries have been widely used for power supplies for electric vehicles, power supplies for mobile phone terminals, and the like. In addition, from the viewpoint of improving safety, development of all-solid-state secondary batteries in which all of the electrode layers and the electrolyte layers are made of inorganic solids is also advancing as lithium ion secondary batteries that do not use a liquid electrolyte (electrolytic solution). However, lithium, which is an essential component of a lithium ion secondary battery, is not abundant in resources, and thus has technical problems in terms of cost, supply, and the like. For this reason, sodium which is abundant in resource reserves and inexpensive is attracting attention, and sodium ion secondary batteries (aqueous sodium ion secondary batteries) including aqueous electrolyte are being developed (for example, patent documents 1 to 4). Since a water-based sodium ion secondary battery can use sodium existing in a large amount in sea water as a raw material, it is advantageous in terms of cost, and is considered to have a development prospect from the viewpoint of easiness in securing resources. In addition, in terms of safety, which may be a problem in the case of an increase in size, the electrolyte of the aqueous solution is extremely difficult to ignite because the electrolyte of the organic solvent often used in the lithium ion secondary battery has an ignition point of about 140 ℃. Prior art literature Patent literature Patent document 1 Japanese patent application laid-open No. 2011-086402 Patent document 2 Japanese patent application laid-open No. 2012-003928 Patent document 3 Japanese patent application laid-open No. 2012-054208 Patent document 4 Japanese patent application laid-open No. 2017-124951 Disclosure of Invention Technical problem to be solved by the invention Here, in an aqueous alkali metal ion secondary battery including an electrolyte of an aqueous solution, hydrogen gas or the like is problematic due to electrolysis of water at the time of charging. In particular, although the aqueous sodium ion secondary battery has advantages in terms of cost and the like as described above, it is said that it is difficult to suppress the generation of hydrogen gas at the time of charging, and if the generated hydrogen gas stays on the anode, it is difficult for current to flow due to polarization, regardless of the anode active material used. In order to solve the problem that an aqueous alkali metal ion secondary battery having a high electromotive force is obtained while suppressing hydrogen generation or the like, for example, in an aqueous lithium ion secondary battery, a form has been conceived in which a lithium ion solid electrolyte having high water resistance and also high lithium ion conductivity and water resistance is used as an electrolyte separator disposed between a positive electrode and a negative electrode. However, as for sodium ion conductive materials, solid electrolytes having a crystalline phase of NASICON structure typified by Na 3Zr2Si2PO12 are known, but it is also known that the sinterability is poor, and an electrolyte separator having a dense and high water resistance cannot be obtained. Patent document 4 discloses a method of impregnating a molten hydrocarbon (resin) into voids in a Na 3Zr2Si2PO12 molded article (a joint body) and finally obtaining a sodium ion conductive material having high water repellency by subjecting the surface to plasma treatment to exhibit sodium ion conductivity, but this method is a method of filling Na 3Zr2Si2PO12 in the voids with hydrocarbon, and therefore it is difficult to say that the method has high sodium ion conductivity, and further, since hydrocarbon having low durability is contained, there is a high possibility that long-term water repellency cannot be obtained at the joint interface between hydrocarbon and Na 3Zr2Si2PO12 or the like. Accordingly, an object of the present invention is to provide a sodium ion conductive glass ceramic which has a compact structure, high water repellency, and high sodium ion conductivity, and which can be used for an electrolyte separator for an aqueous sodium ion secondary battery. Method for solving technical problems As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that a sodium ion conductive glass ceramic containing, in mol% in terms of oxide, 20.0% to 27.0% of Na 2 O component, 30.0% to 40.0% of ZrO 2 component, 3.0% to 20.0% of P 2O5 component and 20.0% to 40.0% of SiO 2 component, and containing monoclinic crystal phase represented by Na 1＋xZr2SixP3－xO12 (0 < X < 3), wherein the