Garnet-type solid electrolyte and method for preparing the same

Patent metadata

Field	Value
Publication number	US-2016190639-A1
Application number	US-201514935762-A
Country	US
Kind code	A1
Filing date	Nov 9, 2015
Priority date	Dec 30, 2014
Publication date	Jun 30, 2016
Grant date	—

Abstract

Disclosed are a garnet-type solid electrolyte and a method for preparing the same. The garnet-based solid electrolyte of the present invention is prepared by adding Al 2 O 3 to a precursor containing hydroxide, thereby enhancing sintered density and ionic conductivity while having a pure cubic phase crystal structure without including impurities.

First claim

What is claimed is:

1 . A garnet-type solid electrolyte, comprising a compound represented by the following chemical formula (I):
[Li a La b Zr c O d ] wherein, in the chemical formula (I), a ranges from about 6.3 to about 8, b ranges from about 2.7 to about 3.3, c ranges from about 1.7 to about 2.3, and d is determined based on available valences in view of the a, the b and the c.

2 . The garnet-type solid electrolyte of claim 1 , wherein the garnet-type solid electrolyte comprises LLZ (Li 7 La 3 Zr 2 O 12 ) having a cubic phase.

3 . The garnet-type solid electrolyte of claim 2 , wherein, the LLZ comprises Al which substitutes at least a portion of the Li.

4 . The garnet-type solid electrolyte of claim 3 , wherein the substituted Al is of about 0.02 to 1.075 mol.

5 . The garnet-type solid electrolyte of claim 1 , wherein the garnet-type solid electrolyte has ionic conductivity of 2×10 −4 to 6×10 −4 S/cm.

6 . A method for preparing a garnet-type solid electrolyte represented by the following chemical formula (I), the method comprising:
preparing a mixture of LiOH, La(OH) 3 , ZrO 2 , and Al 2 O 3 ,
[Li a La b Zr c O d ]  [chemical formula (I)]

wherein, in the chemical formula (I), a ranges from about 6.3 to about 8, b ranges from about 2.7 to about 3.3, c ranges from about 1.7 to about 2.3, and d is determined based on available valences in view of the a, the b and the c.

7 . The method of claim 6 , wherein the mixture is prepared by a first dry mixing.

8 . The method of claim 6 , wherein, the mixture is prepared by mixing the LiOH, the La(OH) 3 , and the ZrO 2 and by adding the Al 2 O 3 thereto.

9 . The method of claim 6 , wherein the mixture is prepared by mixing the LiOH, the La(OH) 3 , the ZrO 2 and the Al 2 O 3 at the same time.

10 . The method for preparing a garnet-type solid electrolyte of claim 6 , wherein the garnet-type solid electrolyte includes the LiOH, the La(OH) 3 and the ZrO 2 at a molar ratio of about 6.5 to 8.3:about 3:about 2.

11 . The method of claim 6 , wherein the garnet-type solid electrolyte includes LLZ (Li 7 La 3 Zr 2 O 12 ) having a cubic phase.

12 . The method of claim 11 , wherein the LLZ comprises Al which substitutes at least a portion of the Li.

13 . The method of claim 12 , wherein the substituted Al is of about 0.02 to 1.075 mol.

14 . The method of claim 6 , wherein the garnet-type solid electrolyte comprises a content of the Al 2 O 3 in an amount of about 0.5 to 1.5% by weight with respect to the total weight of the mixture.

15 . The method of claim 6 , further comprising, after the mixing of Al 2 O 3 :
first calcinating the mixture for 5 to 7 hours at 800 to 1000° C.; second dry mixing the calcinated mixture after natural cooling; preparing the second dry mixed mixture into pellets of 8 to 12 mm at 120 to 150 MPa; and preparing a cubic phase garnet-type solid electrolyte by second calcinating the prepared pellets for 10 to 40 hours at 1100 to 1300° C.

16 . The method of claim 15 , further comprising preparing pellets including an amount of about 10 to 80% by weight of the mixture prior to the second calcination, and covering the pellets with the remaining mixture in a powder state.

17 . The method of claim 15 , further comprising analyzing the garnet-type solid electrolyte, wherein the analysis is carried out using X-Ray Diffraction (XRD), Raman Spectroscopy or Inductively Coupled Plasma Mass Spectrometry (ICP-MS).

18 . An all-solid state battery that comprises a garnet-type solid electrolyte of claim 1 .

Assignees

• Hyundai Motor Co Ltd

Inventors

• Sung Ju Young
• Kwon Eun Ji
• Kim Ji Na
• Jang Yong Jun

Classifications

• H01M2300/0071

  Oxides · CPC title

• H01M10/0562 Primary

  Solid materials · CPC title

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title

• Y02P70/50

  Manufacturing or production processes characterised by the final manufactured product · CPC title

• H01M10/058

  Construction or manufacture · CPC title