Material for positive electrode, electrode sheet for all-solid state secondary battery, all-solid state secondary battery, and methods for manufacturing electrode sheet for all-solid state secondary battery and all-solid state secondary battery

1. A material for a positive electrode comprising:

a positive electrode active material:

an inorganic solid electrolyte having conductivity of ions of metals belonging to Group I or II of the periodic table;

an auxiliary conductive agent; and

a dispersant including a compound having a functional group equivalent of 30 to 3,000 and having at least one selected from a group of functional groups (I),

group of functional groups (I): acidic groups, (meth)acryloyl groups, (meth)acryloyloxy groups, (meth)acrylamide groups, alkoxysilyl groups, epoxy groups, oxetanyl groups, isocyanate groups, cyano groups, and mercapto groups,

wherein the compound is a compound represented by General Formula (D) or a compound including a structure in which at least one hydrogen atom in the compound is substituted with a bond,

in General Formula (D), ring α represents a condensed polycycle, R D1 represents a substituent bonded to a constituent atom of the ring α, and d1 represent an integer of 1 or more, in a case in which d1 is 2 or more, a plurality of R D1 's may be identical to or different from each other, in addition, two R D1 's substituting the same atom may be bonded to each other and thus form ═O or an alkylidene group, and R D1 's substituting atoms adjacent to each other may be bonded to each other and thus form a ring, provided that, in a case in which an epoxy ring or an oxetane ring is not condensed into the ring α, at least one R D1 is a functional group selected from the group of functional groups (I) or a group including the functional group.

2. The material for a positive electrode according to claim 1 ,

wherein a specific surface area of the auxiliary conductive agent is 50 m 2 /g or less.

3. The material for a positive electrode according to claim 1 ,

wherein the auxiliary conductive agent is made of a carbon material, and a length Lc of a crystallite in a c-axis direction of the carbon material is 100 angstroms or more.

4. The material for a positive electrode according to claim 1 ,

wherein 0.01% to 10% by mass of the auxiliary conductive agent is included.

5. The material for a positive electrode according to claim 1 ,

wherein an average particle diameter of the auxiliary conductive agent is 0.1 to 50 μm.

6. The material for a positive electrode according to claim 1 ,

wherein the inorganic solid electrolyte is a sulfide-based inorganic solid electrolyte.

7. The material for a positive electrode according to claim 1 ,

wherein the ring α is a condensed polycyclic hydrocarbon ring of three or more rings into which an epoxy ring or an oxetane ring may be condensed.

8. The material for a positive electrode according to claim 1 ,

wherein 0.01% to 10% by mass of the dispersant is included with respect to the auxiliary conductive agent.

9. An electrode sheet for an all-solid state secondary battery produced by applying the material for a positive electrode according to claim 1 onto a metal foil.

10. An all-solid state secondary battery comprising:

a positive electrode active material layer;

a negative electrode active material layer; and

an inorganic solid electrolyte layer,

wherein the positive electrode active material layer is produced by applying the material for a positive electrode according to claim 1 to form a layer.

11. A method for manufacturing an electrode sheet for an all-solid state secondary battery, the method comprising:

applying the material for a positive electrode according to claim 1 onto a metal foil to form a film.

12. A method for manufacturing an all-solid state secondary battery, the method comprising:

manufacturing an all-solid state secondary battery through the manufacturing method according to claim 11 .