Sulfide solid electrolyte

1. A sulfide solid electrolyte, comprising lithium, phosphorus, sulfur and at least one element X selected from the group consisting of a halogen element and a chalcogen element excluding sulfur, wherein:

the sulfide solid electrolyte comprises an argyrodite-type crystal structure;

a molar ratio of the lithium to the phosphorus, A (Li/P), a molar ratio of the sulfur to the phosphorus, B (S/P), and a molar ratio of the element X to the phosphorus, C (X/P), satisfy

formulas (1) to (3):

5.0 ≤A≤ 7.1  (1)

1.0 <A−B≤ 1.5  (2)

6.5≤ A+C< 7.1  (3); and

B>0 and C>0.

2. The sulfide solid electrolyte according to claim 1 , comprising a composition represented by formula (4):

Li a (P 1-z M z )S b X c   (4),

wherein:

M is one or more of elements selected from the group consisting of Si, Ge, Sn, Pb, B, Al, Ga, As, Sb and Bi;

X is one or more of elements selected from the group consisting of F, Cl, Br, I, O, Se and Te;

a is A(1−z);

b is B(1−z);

c is C(1−z); and

z satisfies 0≤z≤0.3.

3. The sulfide solid electrolyte according to claim 2 , wherein the X is one or more of halogen elements selected from the group consisting of F, Cl, Br and I.

4. The sulfide solid electrolyte according to claim 1 , wherein diffraction peaks are measured at 2θ=25.2 ±0.5 deg and 29.7±0.5 deg in a powder X-ray diffraction of the sulfide solid electrolyte using CuKα rays.

5. An electrode mix, comprising the sulfide solid electrolyte of claim 1 and an active material.

6. A lithium ion battery, comprising the sulfide solid electrolyte of claim 1 .

7. An electrode mix produced from the sulfide solid electrolyte of claim 1 .

8. A lithium ion battery produced from the electrode mix according to claim 7 .

9. A lithium ion battery, comprising the electrode mix of claim 5 .

10. The sulfide solid electrolyte according to claim 1 , wherein the sulfide solid electrolyte comprising a composition represented by formula (4):

Li a (P 1-z M z )S b X c   (4)

wherein:

M is one or more of elements selected from the group consisting of Si, Ge, Sn, Pb, B, Al, Ga, As, Sb and Bi;

X is one or more of elements selected from the group consisting of F, Cl, Br, I, O, Se and Te;

a is A(1−z);

b is B(1−z);

c is C(1−z); and

z is 0.

11. The sulfide solid electrolyte according to claim 1 , wherein the sulfide solid electrolyte comprising a composition represented by formula (4):

Li a (P 1-z M z )S b X c   (4)

wherein:

M is one or more of elements selected from the group consisting of Si, Ge, Sn, Pb, B, Al, Ga, As, Sb and Bi;

X is one or more of elements selected from the group consisting of F, Cl, Br and I;

a is A(1−z);

b is B(1−z);

c is C(1−z); and

z satisfies 0≤z≤0.3.

12. The sulfide solid electrolyte according to claim 1 , wherein the sulfide solid electrolyte comprising a composition represented by formula (4):

Li a (P 1-z M z )S b X c   (4)

wherein:

M is one or more of elements selected from the group consisting of Si, Ge, Sn, Pb, B, Al, Ga, As, Sb and Bi;

X is one or more of halogen elements selected from the group consisting of Cl and Br;

a is A(1−z);

b is B(1−z);

c is C(1−z); and

z satisfies 0≤z≤0.3.

13. The sulfide solid electrolyte according to claim 1 , wherein:

the sulfide solid electrolyte comprising a composition represented by formula (4):

Li a (P 1-z M z )S b X c   (4)

wherein:

M is one or more of elements selected from the group consisting of Si, Ge, Sn, Pb, B, Al, Ga, As, Sb and Bi;

X is one or more of elements selected from the group consisting of F, Cl, Br, I, O, Se and Te;

a is A(1−z);

b is B(1−z);

c is C(1−z); and

z satisfies 0≤z≤0.3; and

diffraction peaks are measured at 2θ=25.2±0.5 deg and 29.7±0.5 deg in a powder X-ray diffraction of the sulfide solid electrolyte using CuKα rays.

14. The sulfide solid electrolyte according to claim 1 , wherein:

the sulfide solid electrolyte comprising a composition represented by formula (4):

Li a (P 1-z M z )S b X c   (4)

wherein:

M is one or more of elements selected from the group consisting of Si, Ge, Sn, Pb, B, Al, Ga, As, Sb and Bi;

X is one or more of elements selected from the group consisting of F, Cl, Br, I, O, Se and Te;

a is A(1−z);

b is B(1−z);

c is C(1−z); and

z satisfies 0≤z≤0.3; and

the sulfide solid electrolyte does not have a diffraction peak at 2θ=17.6±0.4 deg and 2θ=18.1±0.4 deg in powder X-ray diffraction using CuKα rays, or the sulfide solid electrolyte has a diffraction peak at 2θ=17.6±0.4 deg and 2θ=18.1±0.4 deg in powder X-ray diffraction using CuKα rays and satisfies formula (5):

0 <I A /I B <0.05  (5)

wherein:

I A represents the intensity of the diffraction peak which is not a diffraction peak derived from the argyrodite-type crystal structure between diffraction peaks at 2θ=17.6±0.4 deg and 2θ=18.1±0.4 deg; and

I B represents the intensity of the diffraction peak at 2θ=29.7±0.5 deg.

15. The sulfide solid electrolyte according to claim 1 , wherein the sulfide solid electrolyte comprising a composition represented by formula (4):

Li a (P 1-z M z )S b X c   (4)

wherein:

M is one or more of elements selected from the group consisting of Si, Ge, Sn, Pb, B, Al, Ga, As, Sb and Bi;

X is one or more of elements selected from the group consisting of F, Cl, Br and I;

a is A(1−z);

b is B(1−z);

c is C(1−z); and

z is 0.

16. The sulfide solid electrolyte according to claim 1 , wherein the sulfide solid electrolyte comprising a composition represented by formula (4):

Li a (P 1-z M z )S b X c   (4)

wherein:

M is one or more of elements selected from the group consisting of Si, Ge, Sn, Pb, B, Al, Ga, As, Sb and Bi;

X is one or more of halogen elements selected from the group consisting of Cl and Br;

a is A(1−z);

b is B(1−z);

c is C(1−z); and

z is 0.

17. The sulfide solid electrolyte according to claim 1 , wherein:

the sulfide solid electrolyte comprising a composition represented by formula (4):

Li a (P 1-z M z )S b X c   (4)

wherein:

M is one or more of elements selected from the group consisting of Si, Ge, Sn, Pb, B, Al, Ga, As, Sb and Bi;

X is one or more of elements selected from the group consisting of F, Cl, Br, I, O, Se and Te;

a is A(1−z);

b is B(1−z);

c is C(1−z) and

z is 0; and

diffraction peaks are measured at 2θ=25.2±0.5 deg and 29.7±0.5 deg in a powder X-ray diffraction of the sulfide solid electrolyte using CuKα rays.

18. The sulfide solid electrolyte according to claim 1 , wherein:

the sulfide solid electrolyte comprising a composition represented by formula (4):

Li a (P 1-z M z )S b X c   (4)

wherein:

M is one or more of elements selected from the group consisting of Si, Ge, Sn, Pb, B, Al, Ga, As, Sb and Bi;

X is one or more of elements selected from the group consisting of F, Cl, Br, I, O, Se and Te;

a is A(1−z);

b is B(1−z);

c is C(1−z); and

z is 0; and

the sulfide solid electrolyte does not have a diffraction peak at 2θ=17.6±0.4 deg and 2θ=18.1±0.4 deg in powder X-ray diffraction using CuKα rays, or the sulfide solid electrolyte has a diffraction peak at 2θ=17.6±0.4 deg and 2θ=18.1±0.4 deg in powder X-ray diffraction using CuKα rays and satisfies formula (5):

0 <I A /I B <0.05  (5)

wherein:

I A represents the intensity of the diffraction peak which is not a diffraction peak derived from the argyrodite-type crystal structure between diffraction peaks at 2θ=17.6±0.4 deg and 2θ=18.1±0.4 deg; and

I B represents the intensity of the diffraction peak at 2θ=29.7±0.5 deg.

19. The sulfide solid electrolyte according to claim 1 , wherein:

the sulfide solid electrolyte comprising a composition represented by formula (4):

Li a (P 1-z M z )S b X c   (4)

wherein:

M is one or more of elements selected from the group consisting of Si, Ge, Sn, Pb, B, Al, Ga, As, Sb and Bi;

X is one or more of halogen elements selected from the group consisting of Cl and Br;

a is A(1−z);

b is B(1−z);

c is C(1−z); and

z satisfies 0≤z≤0.3; and

diffraction peaks are measured at 2θ=25.2±0.5 deg and 29.7±0.5 deg in a powder X-ray diffraction of the sulfide solid electrolyte using CuKα rays.

20. The sulfide solid electrolyte according to claim 1 , wherein:

the sulfide solid electrolyte comprising a composition represented by formula (4):

Li a (P 1-z M z )S b X c   (4)

wherein:

M is one or more of elements selected from the group consisting of Si, Ge, Sn, Pb, B, Al, Ga, As, Sb and Bi;

X is one or more of halogen elements selected from the group consisting of Cl and Br;

a is A(1−z);

b is B(1−z);

c is C(1−z); and

z satisfies 0≤z≤0.3; and

the sulfide solid electrolyte does not have a diffraction peak at 2θ=17.6±0.4 deg and 2θ=18.1±0.4 deg in powder X-ray diffraction using CuKα rays, or the sulfide solid electrolyte has a diffraction peak at 2θ=17.6±0.4 deg and 2θ=18.1±0.4 deg in powder X-ray diffraction using CuKα rays and satisfies formula (5):

0 <I A /I B <0.05  (5)

wherein:

I A represents the intensity of the diffraction peak which is not a diffraction peak derived from the argyrodite-type crystal structure between diffraction peaks at 2θ=17.6±0.4 deg and 2θ=18.1±0.4 deg; and

I B represents the intensity of the diffraction peak at 2θ=29.7±0.5 deg.

21. The sulfide solid electrolyte according to claim 1 , wherein:

diffraction peaks are measured at 2θ=25.2±0.5 deg and 29.7±0.5 deg in a powder X-ray diffraction of the sulfide solid electrolyte using CuKα rays; and

the sulfide solid electrolyte does not have a diffraction peak at 2θ=17.6±0.4 deg and 2θ=18.1±0.4 deg in powder X-ray diffraction using CuKα rays, or the sulfide solid electrolyte has a diffraction peak at 2θ=17.6±0.4 deg and 2θ=18.1±0.4 deg in powder X-ray diffraction using CuKα rays and satisfies formula (5):

0 <I A /I B <0.05  (5)

wherein:

I A represents the intensity of the diffraction peak which is not a diffraction peak derived from the argyrodite-type crystal structure between diffraction peaks at 2θ=17.6±0.4 deg and 2θ=18.1±0.4 deg; and

I B represents the intensity of the diffraction peak at 2θ=29.7±0.5 deg.

22. The sulfide solid electrolyte according to claim 1 , wherein the molar ratio of the lithium to the phosphorus, A (Li/P), the molar ratio of the sulfur to the phosphorus, B (S/P), and the molar ratio of the element X to the phosphorus, C (X/P), satisfy formulas (1′) to (5′):

5.12≤ A≤ 5.81  (1′)

3.90≤ B≤ 4.67  (2′)

1.10≤ C≤ 1.75  (3′)

1.0< A−B≤ 1.5  (4′)

6.5≤ A+C< 7.1  (5′).