A method of synthesizing a solid-state electrolyte where P.sub.2S.sub.5, Na.sub.2S and LiCl are dissolved in one of more solvents; where upon reacting of the mixture, NaCl precipitates out and is removed from the solution; the solvent is removed; and the sulfide solid-state electrolyte is dried, then crystalized to be used in a solid-state battery. A solid-state battery comprising the produced sulfide solid-state electrolyte is also described.

A sulfide solid electrolyte particles comprising lithium, phosphorus and sulfur, having a volume-based average particle size measured by laser diffraction particle size distribution measurement of 0.1 μm to 10 μm, having a diffraction peak having 2θ of 29.0 to 31.0 deg in powder X-ray diffraction measurement using CuKα ray, and an intensity ratio (Ib/Ip) of a peak intensity Ib at a high angle-side low part of the diffraction peak to a peak intensity Ip of the diffraction peak is less than 0.09.

A sulfide solid electrolyte particles comprising lithium, phosphorus and sulfur, having a volume-based average particle size measured by laser diffraction particle size distribution measurement of 0.1 μm to 10 μm, having a diffraction peak having 2θ of 29.0 to 31.0 deg in powder X-ray diffraction measurement using CuKα ray, and an intensity ratio (Ib/Ip) of a peak intensity Ib at a high angle-side low part of the diffraction peak to a peak intensity Ip of the diffraction peak is less than 0.09.

A method for producing a sulfide solid electrolyte includes: forming an Li—P—S homogeneous solution prepared by mixing Li2S and P2S5 with each other in an organic solvent so that the Li2S/P2S5 molar ratio is from 0.7 to 1.5; forming an Li—Si—S homogeneous solution, which contains prepared containing at least elemental lithium (Li), elemental silicon (Si) and elemental sulfur (S) in an organic solvent; mixing a homogeneous mixed solution prepared by mixing the Li—P—S homogeneous solution and the Li—Si—S homogeneous solution with each other; forming a slurry prepared by mixing the homogeneous mixed solution and Li2S with each other; drying a precursor obtained by removing the organic solvent from the slurry; and a heating a sulfide solid electrolyte obtained by heating the precursor at 200-700° C.

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.

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.

A solid electrolyte material comprises Li, T, X and A wherein T is at least one of P, As, Si, Ge, Al, and B; X is one or more halogens or N; A is one or more of S and Se. The solid electrolyte material has peaks at 17.8°±0.75° and 19.2°±0.75° in X-ray diffraction measurement with Cu-Kα(1,2)=1.5418 Å and may include glass ceramic and/or mixed crystalline phases.

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 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.

Improved methods of synthesizing ammonia from hydrogen sulfide and lithium nitrate are disclosed. Specifically, in a continuous cycle, hydrogen sulfide reactant is regenerated from the elemental sulfur that is extracted from a product of the ammonia synthesis, and the regenerated hydrogen sulfide is fed back into the ammonia synthesis reaction. The cycle that regenerates the hydrogen sulfide uses either a water-containing or a water and carbon-containing feedstock to facilitate the regeneration of the hydrogen sulfide from the elemental sulfur.