Negative electrode material for sodium secondary battery and method for producing same, negative electrode for sodium secondary batter, and sodium secondary battery

1. A negative electrode material for a sodium secondary battery comprising a composite powder of component A and component B,

wherein (1) the component A is a material capable of electrochemically absorbing and releasing sodium; and

(2) the component B is a sulfide or a sulfide composite body including sulfur, antimony, and the following component(s) of (i):

(i) at least one or more element(s) selected from a group consisting of Sn, As, Bi, Ge, Ga, Pb, and C,

wherein a ratio of the sulfur, the antimony, and the component(s) of (i) is sulfur: 10 to 70 mol %, antimony: 10 to 70 mol %, and (i): 3 to 60 mol %.

2. The negative electrode material according to claim 1 , wherein the composite powder is a composite powder with a surface of the component A coated with the component B.

3. The negative electrode material according to claim 2 , wherein a ratio of the component A and the component B of the entire composite powder is the component A: 40 to 95 mass %, and the component B: 60 to 5 mass %, given that a total amount of both is 100 mass %.

4. The negative electrode material according to claim 1 , wherein a ratio of the component A and the component B of the entire composite powder is the component A: 40 to 95 mass %, and the component B: 60 to 5 mass %, given that a total amount of both is 100 mass %.

5. A negative electrode for a sodium secondary battery including the negative electrode material according to claim 1 .

6. The negative electrode of claim 5 , wherein the sulfide composite body includes sulfide glass, and includes 0.5 to 40 mol % of Ge.

7. The negative electrode according to claim 6 , wherein the negative electrode includes a polyimide binder.

8. The negative electrode according to claim 5 , wherein the negative electrode includes a polyimide binder.

9. The negative electrode material according to claim 1 , wherein the sulfide composite body includes sulfide glass, and includes 0.5 to 40 mol % of Ge.

10. The negative electrode material of claim 1 , wherein component B includes Sn.

11. A sodium secondary battery including the negative electrode according to claim 5 .

12. The sodium secondary battery according to claim 11 , wherein an electrolyte has an NaPF 6 dissolved in a mixed solvent, and the mixed solvent includes a main solvent containing ethylene carbonate and a sub solvent containing one or more solution(s) selected from propylene carbonate, ethyl methyl carbonate, dimethyl carbonate, and diethyl carbonate.

13. A negative electrode material for a sodium secondary battery comprising a composite powder of component A and component B,

wherein (1) the component A is a material capable of electrochemically absorbing and releasing sodium; and

(2) the component B is sulfide or sulfide composite body including sulfur and antimony

wherein the composite powder is a composite powder with a surface of the component A coated with the component B.

14. The negative electrode material according to claim 13 , wherein a ratio of the component A and the component B of the entire composite powder is the component A: 40 to 95 mass %, and the component B: 60 to 5 mass %, given that a total amount of both is 100 mass %.

15. A negative electrode including the negative electrode material according to claim 13 , wherein

a weight ratio of the component A to the component B of the entire composite powder is from 40:60 to 95:5;

the sulfide composite body includes sulfide glass, and includes 0.5 to 40 mol % of Ge; and

the negative electrode has a binder including a polyvinylidene fluoride, a polytetrafluoroethylene, a polyimide, a polyamide, a polyamide-imide, a polyacryl, a styrene-butadiene rubber, a styrene-ethylene-buthylene-styrene copolymer, a carboxymethylcellulose, a polyacrylic, a PVA, a PVB, or an EVA.

16. A method of manufacturing a negative electrode material for a sodium secondary battery comprising a composite powder of component A and component B, wherein;

(1) the component A is a material capable of electrochemically absorbing and releasing sodium; and

(2) the component B is the sulfide or the sulfide composite body including sulfur, antimony, and the following component(s) of (i):

(i) at least one or more element(s) selected from a group consisting of Sn, As, Bi, Ge, Ga, Pb, and C,

wherein a ratio of the sulfur, the antimony, and the component(s) of (i) is sulfur: 10 to 70 mol %, antimony: 10 to 70 mol %, and (i): 3 to 60 mol %,

the method comprising the steps of:

step (A) obtaining the component B by preparing a material of the component B and by making a solid solution of the prepared material through heat treatment at a temperature of 400 to 1100° C.; and

step (B) making a composite of the component A and the component B.

17. The method according to claim 16 , wherein the step (B) is a step of making a composite of the component A and the component B through mechanical milling.

18. The method according to claim 16 , wherein the step (B) is a step of dispersing the component A in the melted component B and crushing it after cooling.

19. The method according to claim 16 , wherein a conductive aid and/or binder is added during the step (A) and/or step (B) and thus the conductive aid and/or binder is included in the composite powder.

20. The method of claim 16 wherein:

the heat treatment is for a time of 1 to 30 hours;

a weight ratio of the component A to the component B of the entire composite powder is from 40:60 to 95:5;

a conductive aid and/or binder is added during the step (A) and/or step (B) and thus the conductive aid and/or binder is included in the composite powder; and

the sulfide composite body includes sulfide glass, and includes 0.5 to 40 mol % of Ge.