Increasing ionic conductivity of LiTi2(PS4)3 by Al doping

Patent metadata

Field	Value
Publication number	US-10807877-B2
Application number	US-201616326117-A
Country	US
Kind code	B2
Filing date	Oct 28, 2016
Priority date	Oct 28, 2016
Publication date	Oct 20, 2020
Grant date	Oct 20, 2020

Abstract

A compound represented by the general formula Li1+xAlxTi2−x(PS4)3, wherein 0.1≤x≤0.75. The above compound has been found to have high ionic conductivity. Also, the use of the compound as a solid electrolyte, in particular in an all solid-state lithium battery.

First claim

The invention claimed is:

1. A solid electrolyte compound represented by the general formula Li 1+x Al x Ti 2−x (PS 4 ) 3 , wherein 0.1≤x≤0.75.

2. The solid electrolyte compound according to claim 1 , wherein 0.3≤x≤0.6.

3. The solid electrolyte compound according to claim 1 , wherein 0.4≤x≤0.6.

4. The solid electrolyte compound according to claim 1 , wherein x=0.5.

5. The solid electrolyte compound according to claim 1 , having peaks in positions of 2θ=15.08° (±0.50°), 15.28° (±0.50°), 15.92° (±0.50°), 17.5° (±0.50°), 18.24° (±0.50°), 20.30° (±0.50°), 23.44° (±0.50°), 24.48° (±0.50°), and 26.66° (±0.50°) in an X-ray diffraction measurement using a CuKα line.

6. Method for preparing the solid electrolyte compound according to claim 1 , comprising the steps of:
(a) providing a mixture of lithium sulfide Li 2 S, phosphorus sulfide P 2 S 5 , aluminum sulfide Al 2 S 3 and titanium sulfide TiS 2 ;
(b) subjecting the mixture prepared in step (a) to a preliminary reaction step through mechanical milling or melt-quenching to produce an intermediate amorphous sulfide mixture;
(c) subjecting the mixture prepared in (b) to a heat treatment step at a maximum plateau temperature of at least 350° C. and less than 500° C.

7. Method according to claim 6 , further comprising the following steps of surface treatment:
(d) compressing the solid electrolyte compound provided in step (c) to form a compressed powder layer; and
(e) sintering the solid electrolyte compound obtained as a compressed powder layer in step (d) at a temperature of at least 200° C. and at most 400° C.

8. A method comprising including the solid electrolyte compound according to claim 1 as a solid electrolyte in an all-solid-state battery system.

9. A method comprising including the solid electrolyte compound according to claim 1 as a solid electrolyte in an all solid-state lithium battery.

10. Solid-state battery comprising the solid electrolyte compound according to claim 1 as a solid electrolyte.

11. All-solid state lithium battery comprising the following elements:
a positive electrode active material layer;
a solid electrolyte layer;
a negative electrode active material layer,
wherein the solid electrolyte layer contains the solid electrolyte compound according to claim 1 .

Assignees

• Toyota Motor Europe

Inventors

• Katoh Yuki

Classifications

• C01B25/16 Primary

  Oxyacids of phosphorus; Salts thereof (peroxyacids or salts thereof C01B15/00) · CPC title

• H01M4/5825

  Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines · CPC title

• H01M10/0562

  Solid materials · CPC title

• H01M2300/002

  Inorganic electrolyte · CPC title

• C01G23/007 Primary

  Titanium sulfides (C01G23/001 takes precedence) · CPC title