The present disclosure relates to compositions that can be used for optical fibers and other systems that transmit light in the near-, mid- and/or far-ranges of the infrared spectrum, such as for example in the wavelength range of 1.5 μm to 14 μm. The optical fibers may comprise a light-transmitting chalcogenide core composition and a cladding composition. In some embodiments, the light-transmitting chalcogenide core composition has a refractive index n(core) and a coefficient of thermal expansion CTE(core), and the cladding composition has a refractive index n(cladding) and a coefficient of thermal expansion CTE(cladding), wherein n(cladding) is less than n(core) and in some embodiments wherein CTE(cladding) is less than CTE(core). In some embodiments, the chalcogenide glass core composition comprises a) sulfur and/or selenium, b) germanium, and c) gallium, indium, tin and/or one or more metal halides.

Provided are a method for producing a sulfide solid electrolyte having a high Li ion conductivity, in which the production time can be greatly reduced, and a sulfur-based material that can be used in the production method for a sulfide solid electrolyte. The invention relates to a method for producing a sulfide solid electrolyte containing a lithium element, a sulfur element, a phosphorus element, an iodine element and a bromine element, which includes mixing and grinding lithium sulfide and lithium bromide followed by adding phosphorus sulfide and lithium iodide thereto and reacting them, and relates to a sulfur-based material.

The present invention provides a production method of a solid electrolyte containing a lithium element, a sulfur element, a phosphorous element, and a halogen element, wherein the solid electrolyte has a high ionic conductivity and capable of suppressing hydrogen sulfide by adopting a liquid-phase method, wherein the method includes mixing a complexing agent having an ester group and also having at least one branch with a solid electrolyte raw material. The present invention also relates to an electrolyte precursor.

Described are a solid material which has ionic conductivity for lithium ions, a process for preparing said solid material, a use of said solid material as a solid electrolyte for an electrochemical cell, a solid structure selected from the group consisting of a cathode, an anode and a separator for an electrochemical cell, and an electrochemical cell comprising such solid structure.

Provided is a method for manufacturing an infrared-transmissive lens having an excellent surface quality. A method for manufacturing an infrared-transmissive lens includes firing a preform of a chalcogenide glass in an inert gas atmosphere to obtain a fired body and then subjecting the fired body to hot press molding.

Disclosed herein is a solid electrolyte, comprising a compound of the formula A.sub.y(MS.sub.4).sub.z(PS.sub.4).sub.4-zX.sub.3, wherein the compound does not consist of Li.sub.15(PS.sub.4).sub.4CI.sub.3, and wherein the solid electrolyte presents an ionic conductivity of from 10.sup.−7 to 10.sup.−3 S/cm at room temperature. Also disclosed herein are methods of making a solid electrolyte.

A sulfide solid electrolyte material having a high Li ion conductivity is provided. A sulfide solid electrolyte material includes Li, P, I and S, having peaks at 2θ=20.2° and 23.6°, not having peaks at 2θ=21.0° and 28.0° in an X-ray diffraction measurement using a CuKα ray, and having a half width of the peak at 2θ=20.2° of 0.51° or less.

Disclosed is a sulfide solid electrolyte of high robustness in its production step and of high lithium ion conductivity, the sulfide solid electrolyte including Li, P, S, Br, I, and N as its constituent elements.

A method for producing a sulfide solid electrolyte material, which is configured to allow the crystallization of a sulfide glass at low temperature. Provided is a method for producing a sulfide solid electrolyte material, the method comprising: amorphizing a raw material composition containing Li.sub.2S, P.sub.2S.sub.5, LiI, LiBr, a potassium-containing compound and Li.sub.3N to obtain a sulfide glass, and crystallizing the sulfide glass by hot-pressing the sulfide glass, wherein, when a first crystallization temperature of the sulfide glass is determined as X, and a second crystallization temperature of the sulfide glass is determined as Y, the first crystallization temperature X of the sulfide glass is 171 C. or less, and a temperature difference (YX) between the second crystallization temperature Y and the first crystallization temperature X is 75 C. or more.

A method for preparing a sulfide solid electrolyte material exhibiting Li ion conductivity. The sulfide solid electrolyte material contains an organic compound having a molecular weight within a range of 30 to 300, and the organic compound is present in an amount of 0.8 wt % or less. The method includes: (i) performing mechanical milling to a mixture of a raw material composition and the organic compound to convert the raw material composition to an amorphous state, thereby synthesizing a sulfide glass; and (ii) drying the sulfide glass such that at least some of the organic compound remains in the sulfide solid electrolyte material.