Provided is a method for producing a solid electrolyte having peaks at 2θ=20.2°±0.5° and 23.6°±0.5° in X-ray diffractometry using a CuKα ray and containing a lithium element, a phosphorus element, a sulfur element, and a halogen element, the method including using raw materials containing yellow phosphorus and a compound containing a lithium element, a sulfur element, and a halogen element.

An electrochromic polymer with polar side chains is disclosed. The viscosity of the electrochromic polymer is controllable by adjusting a ratio between polar side chains and alkyl side chains for forming the electrochromic polymer. The disclosed electrochromic polymer with polar side chains can be also made into a film with a controllable thickness by coating.

A sulfur-containing compound containing a lithium (Li) element, a phosphorus (P) element, a sulfur (S) element, and a halogen (X) element, which can be suitably used as a solid electrolyte, and is able to suppress the generation of a hydrogen sulfide gas even when exposed to moisture in the atmosphere. The sulfur-containing compound has a peak at each position of 2θ=21.3°±1.0°, 27.8°±1.0°, and 30.8°±0.5° in an X-ray diffraction pattern measured by an X-ray diffraction apparatus (XRD) using CuKα1 rays.

Provided are a solid ion conductor represented by Formula 1 and having an argyrodite crystal structure, and a solid electrolyte and an electrochemical cell that include the solid ion conductor:

Li.sub.7-2a-b-cM.sub.aPS.sub.6-a-b-cO.sub.aX1.sub.bX2.sub.c   Formula 1

wherein, in Formula 1, M is zinc (Zn), cadmium (Cd), mercury (Hg), or a combination thereof,

X1 and X2 are each independently chlorine (Cl), bromine (Br), iodine (I), a pseudohalogen, or a combination thereof, and

conditions of 0<a<0.5, 0<b<2, 0<c<2, and 1<b+c<3 are satisfied.

A sulfide glass solid electrolyte sheet can be protected from reaction with moisture by a thin metal layer coating converted to a thin electrochemically functional and protective compound layer. The converted protective compound layer is electrochemically functional in that it allows for through transport of lithium ions.

Disclosed herein are a solid ion conductor compound includinga compound that is represented by Formula 1 and has an argyrodite-type crystal structure, an ion conductivity of 3 mS/cm or more at 25° C., and an average particle diameter of 0.1 .Math.m to 7 .Math.m, a solid electrolyte including the solid ion conductor compound, an electrochemical cell including the solid ion conductor compound, and a method of preparing the solid ion conductor compound.

##STR00001##

In Formula 1, M1 is at least one metal element selected from Group 1 to 15 elements, except for Li, in the Periodic Table, M2 is at least one element selected from Group 17 elements in the Periodic Table, M3 isSO.sub.n, and 4≤a≤8, 0≤x<1, 3≤y≤7, 0<z≤2, 0≤w<2, 1.5≤n≤5, and 0<x+w<3.

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.

Disclosed is a method for producing a sulfide solid electrolyte including a step of processing a slurry by at least one treatment selected from drying and heating, wherein a solid electrolyte raw material containing a lithium element, a sulfur element, a phosphorus element and a halogen element, and a complexing agent are mixed in a reactor to give a complex slurry containing a complex formed of the solid electrolyte raw material and the complexing agent, and the complex slurry is transferred into an intermediate tank equipped with a cooling device and cooled therein.

Disclosed is a method for producing a sulfide solid electrolyte including a step of processing a slurry by at least one treatment selected from drying and heating, wherein a solid electrolyte raw material containing a lithium element, a sulfur element, a phosphorus element and a halogen element, and a complexing agent are mixed in a reactor to give a complex slurry containing a complex formed of the solid electrolyte raw material and the complexing agent, and the complex slurry is transferred into an intermediate tank equipped with a cooling device and cooled therein.