A sulfide solid electrolyte contains elemental lithium (Li), elemental phosphorus (P), and elemental sulfur (S). The sulfide solid electrolyte has at least one peak observed in the chemical shift range of 3.4 ppm to 4.8 ppm in a spectrum obtained by .sup.1H-NMR measurement. It is preferable that the sulfide solid electrolyte has an argyrodite-type crystal structure. It is also preferable that the sulfide solid electrolyte contains an ester compound of a carboxylic acid and an alcohol.

There is provided an inorganic solid electrolyte-containing composition containing an inorganic solid electrolyte, a polymer binder, and a dispersion medium, where the polymer binder has a constitutional component (X) derived from a polycondensable compound having a polycondensable group and a polymerized chain and has a constitutional component (A) derived from a polycondensable compound having a specific functional group, and the inorganic solid electrolyte-containing composition contains a polymer having a constitutional component (N) containing a nitrogen atom, the polymer having a content of less than 10% by mole in all constitutional components and is dissolved in a dispersion medium. There are also provided a sheet for an all-solid state secondary battery and an all-solid state secondary battery, in which this inorganic solid electrolyte-containing composition is used, and manufacturing methods for a sheet for an all-solid state secondary battery, and an all-solid state secondary battery.

A solid electrolyte for all-solid sodium battery expressed by Na.sub.3-xSbS.sub.4-xA.sub.x, wherein A is selected from F, Cl, Br, I, NO.sub.3, BH.sub.4, BF.sub.4, PF.sub.6, ClO.sub.4, BH.sub.4, CF.sub.3SO.sub.3, (CF.sub.3SO.sub.2).sub.2N, (C.sub.2F.sub.5SO.sub.2).sub.2N, (FSO.sub.2).sub.2N, and [B(C.sub.2O.sub.4).sub.2]; and x is 0<x<3.

A sulfide solid electrolyte may include lithium, phosphorus and sulfur, and the sulfide solid electrolyte may have a diffraction peak A at 2θ=25.2±0.5 deg and a diffraction peak B at 29.7±0.5 deg in powder X-ray diffraction using CuKα rays, and a crystallite diameter in a range of from 5 to 20 nm.

A sulfide solid electrolyte having ionic conductivity is provided. The sulfide solid electrolyte contains an organic solvent. The amount of organic solvent contained in the sulfide solid electrolyte is 0.95 mass % or less. It is preferable that the amount of organic solvent contained in the sulfide solid electrolyte is 0.01 mass % or more. It is preferable that the sulfide solid electrolyte has an argyrodite-type crystal structure. Also provided are an electrode mixture including the sulfide solid electrolyte and a positive electrode active material or a negative electrode active material, as well as a solid-state battery including the electrode mixture.

A sulfide solid electrolyte that contains lithium, phosphorus, sulfur, chlorine and bromine, wherein in powder X-ray diffraction analysis using CuKα rays, it has a diffraction peak A at 2θ=25.2±0.5 deg and a diffraction peak B at 2θ=29.7±0.5 deg, the diffraction peak A and the diffraction peak B satisfy the following formula (A), and a molar ratio of the chlorine to the phosphorus “c (Cl/P)” and a molar ratio of the bromine to the phosphorus “d (Br/P)” satisfies the following formula (1):

1.2<c+d<1.9  (1)

0.845<S.sub.A/S.sub.B<1.200  (A) where S.sub.A is an area of the diffraction peak A and S.sub.B is an area of the diffraction peak B.

A sulfide solid electrolyte that contains lithium, phosphorus, sulfur, chlorine and bromine, wherein in powder X-ray diffraction analysis using CuKα rays, it has a diffraction peak A at 2θ=25.2±0.5 deg and a diffraction peak B at 2θ=29.7±0.5 deg, the diffraction peak A and the diffraction peak B satisfy the following formula (A), and a molar ratio of the chlorine to the phosphorus “c (Cl/P)” and a molar ratio of the bromine to the phosphorus “d (Br/P)” satisfies the following formula (1):

1.2<c+d<1.9  (1)

0.845<S.sub.A/S.sub.B<1.200  (A) where S.sub.A is an area of the diffraction peak A and S.sub.B is an area of the diffraction peak B.

A sulfide solid electrolyte is provided having peak A at 2θ=20.7°±0.5° in an X-ray diffraction pattern obtained by performing X-ray diffraction measurement using CuKα1 radiation. It is preferable that the sulfide solid electrolyte has peak B at 2θ=25.4°±1.0° in the X-ray diffraction pattern obtained by performing X-ray diffraction measurement using CuKα1 radiation. It is also preferable that the value of the ratio of I.sub.A to I.sub.B, I.sub.A/I.sub.B, is more than 0 and 0.7 or less, where I.sub.A is the intensity of peak A and I.sub.B is the intensity of peak B. It is also preferable that the sulfide solid electrolyte has peak C at 2θ=22.0°±0.5° in the X-ray diffraction pattern obtained by performing X-ray diffraction measurement using CuKα1 radiation.

A sulfide solid electrolyte to be use in a lithium-ion secondary battery includes an argyrodite crystal structure represented by Li.sub.aPS.sub.bHa.sub.c (where 5≤a≤7, 4≤b≤6, and 0<c≤2, and Ha represents a halogen element), in which in an X-ray diffraction spectrum using a Cu-Kα ray, the argyrodite crystal structure has a peak A and a peak B, each having a full width at half maximum of 0.07° or more, within a range of 2θ=30.3°±0.5°, and a difference between diffraction angles (2θ) of the peak A and the peak B is 0.05° or more.

A solid electrolyte material may be advantageously synthesized using a multipart solvent/solution based method employing selective solvation and/or particle size reduction for different reactants used to form the solid electrolyte.