Solid electrolyte composition, binder for all-solid-state secondary batteries, and electrode sheet for batteries and all-solid-state secondary battery each using said solid electrolyte

A solid electrolyte composition comprising:

• an inorganic solid electrolyte having conductivity of an ion of metal belong to Group 1 or 2 in the periodic table;
• and
• a high polymer binder,
• wherein the high polymer binder is formed of a polymer having a hard segment and a soft segment and further having a third component other than the hard segment and the soft segment, and
• wherein the polymer has a repeating structure expressed by Formula (3) below,
• in Formula (3), R12a represents an arylene group having 6 to 22 carbon atoms, an alkylene group having 1 to 15 carbon atoms, and a combination thereof, R23a represents an alkylene group having 2 to 6 carbon atoms, R23b represents an alkylene group having an acidic group of which an acid dissociation constant pKa is 14 or less or a basic group in which a pKa of a conjugate acid is 14 or less, R23c represents an alkylene group having a radical or cationic polymerizable group, R23d represents a diol residue having a molecular weight of 500 to 10,000, and a glass-transition temperature of −100° C. to 50° C., x represents 40 mol % to 60 mol %, y1 represents 0 mol % to 40 mol %, y2 represents 1 mol % to 20 mol %, y3 represents 1 mol % to 40 mol %, y4 represents 1 mol % to 40 mol %, x+y1+y2+y3+y4 is 100 mol %, and * represents a bonding position.