Sulfide solid electrolyte material, battery, and method for producing sulfide solid electrolyte material
The problem of the present invention is to provide a sulfide solid electrolyte material having excellent ion conductivity. The present invention solves the problem by providing a sulfide solid electrolyte material comprising an M 1 element (such as a Li element), an M 2 element (such as a Ge element and a P element), and an S element; having a peak in a position of 2θ=29.58°±0.50° in an X-ray diffraction measurement using a CuKα line; and having an I B /I A value of less than 0.50 when a diffraction intensity at the peak of 2θ=29.58°±0.50° is represented by I A and a diffraction intensity at a peak of 2θ=27.33°±0.50° is represented by I B .
1. A sulfide solid electrolyte material comprising an M 1 element, an M 2 element, and an S element;
wherein M 1 is at least one kind selected from the group consisting of Li, Na, K, Mg, Ca and Zn; and
M 2 is at least one kind selected from the group consisting of P, Sb, Si, Ge, Sn, B, Al, Ga, In, Ti, Zr, V and Nb;
having a peak in positions of 2θ=20.18°±0.50°, 20.44°±0.50°, 26.96°±0.50° and 29.58°±0.50° in an X-ray diffraction measurement using a CuKα line; and
having an I B /I A value of 0.25 or less when a diffraction intensity at the peak of 2θ=29.58°±0.50° is represented by I A and a diffraction intensity at a peak of 2θ=27.33°±0.50° is represented by I B .
2. The sulfide solid electrolyte material according to claim 1 , having a peak in positions of 2θ=17.38°, 23.56°, 23.96°, 24.93°, 29.07°, 29.58°, 31.71°, 32.66° and 33.39° (these positions may be within a range of ±0.50°) in the X-ray diffraction measurement using the CuKα line.
3. The sulfide solid electrolyte material according to claim 1 , wherein M 1 is Li and M 2 is Ge and P.
4. The sulfide solid electrolyte material according to claim 3 , having a composition of Li (4-X) Ge (1-X) P X S 4 (x satisfies 0<x<1).
5. The sulfide solid electrolyte material according to claim 4 , wherein x satisfies 0.5≦x≦0.8.
6. A sulfide solid electrolyte material comprising as a main body a crystal structure having an octahedron O comprising an M 1 element and an S element, a tetrahedron T 1 comprising an M 2a element and an S element, and a tetrahedron T 2 comprising an M 2b element and an S element, in which the tetrahedron T 1 and the octahedron O share an edge, and the tetrahedron T 2 and the octahedron O share a corner; and
wherein M 1 is at least one kind selected from the group consisting of Li, Na, K, Mg, Ca and Zn; and
M 2a and M 2b are each independently at least one kind selected from the group consisting of P, Sb, Si, Ge, Sn, B, Al, Ga, In, Ti, Zr, V and Nb.
7. The sulfide solid electrolyte material according to claim 6 , wherein the octahedron O is an LiS 6 octahedron, in which M 1 is Li;
the tetrahedron T 1 is a GeS 4 tetrahedron and a PS 4 tetrahedron, in which M 2a is Ge and P respectively; and
the tetrahedron T 2 is a PS 4 tetrahedron, in which M 2b is P.
8. The sulfide solid electrolyte material according to claim 6 , having a peak in a position of 2θ=29.58°±0.50° in an X-ray diffraction measurement using a CuKα line; and
having an I B /I A value of 0.25 or less when a diffraction intensity at the peak of 2θ=29.58°±0.50° is represented by I A and a diffraction intensity at a peak of 2θ=27.33°±0.50° is represented by I B .
9. A battery comprising: a cathode active material layer containing a cathode active material, an anode active material layer containing an anode active material, and an electrolyte layer formed between the cathode active material layer and the anode active material layer;
wherein at least one of the cathode active material layer, the anode active material layer, and the electrolyte layer contains the sulfide solid electrolyte material according to claim 1 .
10. A battery comprising: a cathode active material layer containing a cathode active material, an anode active material layer containing an anode active material, and an electrolyte layer formed between the cathode active material layer and the anode active material layer;
wherein at least one of the cathode active material layer, the anode active material layer, and the electrolyte layer contains the sulfide solid electrolyte material according to claim 6 .
11. The battery according to claim 9 , wherein the electrolyte layer is a solid electrolyte layer containing the sulfide solid electrolyte material.
12. The battery according to claim 10 , wherein the electrolyte layer is a solid electrolyte layer containing the sulfide solid electrolyte material.
13. A method for producing a sulfide solid electrolyte material, comprising the steps of:
an ion conductive material synthesizing step of synthesizing a crystalline ion conductive material by using a raw material composition containing an M 1 element (M 1 is at least one kind selected from the group consisting of Li, Na, K, Mg, Ca and Zn), an M 2 element (M 2 is at least one kind selected from the group consisting of P, Sb, Si, Ge, Sn, B, Al, Ga, In, Ti, Zr, V and Nb), and an S element;
a crystallinity decreasing step of decreasing crystallinity of the ion conductive material by mechanical milling; and
a heating step of heating the ion conductive material with the crystallinity decreased to obtain a sulfide solid electrolyte material having a peak in positions of 2θ=20.18°±0.50°, 20.44°±0.50°, 26.96°±0.50° and 29.58°±0.50° in an X-ray diffraction measurement using a CuKα line, and having an I B /I A value of 0.25 or less when a diffraction intensity at the peak of 2θ=29.58°±0.50° is represented by I A and a diffraction intensity at a peak of 2θ=27.33°±0.50° is represented by I B .
14. The method for producing a sulfide solid electrolyte material according to claim 13 , wherein the ion conductive material is synthesized by a solid phase method in the ion conductive material synthesizing step.
15. The method for producing a sulfide solid electrolyte material according to claim 13 , wherein the mechanical milling is vibrating mill.
16. A method for producing a sulfide solid electrolyte material, comprising the steps of:
an ion conductive material synthesizing step of synthesizing an amorphous ion conductive material by mechanical milling by using a raw material composition containing an M 1 element (M 1 is at least one kind selected from the group consisting of Li, Na, K, Mg, Ca and Zn), an M 2 element (M 2 is at least one kind selected from the group consisting of P, Sb, Si, Ge, Sn, B, Al, Ga, In, Ti, Zr, V and Nb), and an S element; and
a heating step of heating the amorphous ion conductive material to obtain a sulfide solid electrolyte material having a peak in positions of 2θ=20.18°±0.50°, 20.44°±0.50°, 26.96°±0.50° and 29.58°±0.50° in an X-ray diffraction measurement using a CuKα line, and having an I B /I A value of 0.25 or less when a diffraction intensity at the peak of 2θ=29.58°±0.50° is represented by I A and a diffraction intensity at a peak of 2θ=27.33°±0.50° is represented by I B .
17. The method for producing a sulfide solid electrolyte material according to claim 16 , wherein the mechanical milling is ball mill or vibrating mill.
18. The method for producing a sulfide solid electrolyte material according to claim 13 , wherein the raw material composition contains Li 2 S, P 2 S 5 and GeS 2 .
19. The method for producing a sulfide solid electrolyte material according to claim 16 , wherein the raw material composition contains Li 2 S, P 2 S 5 and GeS 2 .