Electrode composition, electrode sheet for all-solid state secondary battery, and all-solid state secondary battery, and manufacturing methods for electrode sheet for all-solid state secondary battery and all-solid state secondary battery

An electrode composition comprising:

• an inorganic solid electrolyte having an ion conductivity of a metal belonging to Group 1 or Group 2 in the periodic table;
• an active material;
• a polymer binder;
• and
• a dispersion medium,
• wherein a linear polymer is contained to constitute the polymer binder, and
• a rotation radius α of the polymer binder in the dispersion medium and a median diameter D50 obtained by converting, in terms of content, each of median diameters of the inorganic solid electrolyte and the active material are present within a region (provided that a boundary line is included) of a polygonal shape that has, as apices, a point A (50, 60), a point B (178, 4,600), a point C (85, 4,600), a point D (12, 2,000), and a point E (12, 60) in an orthogonal coordinate system in which the rotation radius α is on an x-axis and the median diameter D50 is on a y-axis, wherein
• the rotation radius α is calculated by a Zimm plot created based on Expression (I), and from a slope of q2 obtained when the zero concentration extrapolation (c→0) has been carried out:
• Kc
• /
• R
• θ
• =
• 1
• M
• w
• ⁢
• (
• 1
• +
• 1
• 3
• ⁢
• α
• 2
• ⁢
• q
• 2
• +
• O
• ⁡
• (
• q
• 4
• )
• )
• +
• 2
• ⁢
• A
• 2
• ⁢
• c
• +
• O
• ⁡
• (
• c
• 2
• )
• Expression
• ⁢
• (
• I
• )
• wherein in Expression (I), K is an optical constant, c is a polymer concentration of the polymer binder, Rθ is an excess Rayleigh ratio, Mw is a mass average molecular weight of the polymer binder, q is a scattering vector, A2 is a second virial coefficient, and
• the median diameter D50 is calculated by the following formula:
• median diameter D50 in nm=(DS-50×WS)+(DA-50×WA),
• whereby DS-50 indicates the median diameter of the inorganic solid electrolyte, DA-50 indicates the median diameter of the active material, WS indicate the mass fraction of the inorganic solid electrolyte with respect to the total mass of the inorganic solid electrolyte and the active material in the electrode composition, and WA indicate the mass fraction of the active material with respect to the total mass of the inorganic solid electrolyte and the active material in the electrode composition.