A sulfide solid electrolyte, which is able to adjust the morphology unavailable traditionally, or is readily adjusted so as to have a desired morphology, the sulfide solid electrolyte having a volume-based average particle diameter measured by laser diffraction particle size distribution measurement of 3 μm or more and a specific surface area measured by the BET method of 20 m.sup.2/g or more; and a method of treating a sulfide solid electrolyte including the sulfide solid electrolyte being subjected to at least one mechanical treatment selected from disintegration and granulation.

The invention relates to a highly reactive, high-purity, free-flowing and dust-free lithium sulfide powder having an average particle size between 250 and 1,500 μm and BET surface areas between 1 and 100 m.sup.2/g. The invention, furthermore, relates to a process for its preparation, wherein in a first step, lithium hydroxide monohydrate is heated in a temperature-controlled unit to a reaction temperature between 150° C. and 450° C. in the absence of air, and an inert gas is passed over or through it, until the residual water of crystallization content of the formed lithium hydroxide is less than 5 wt. % and in a second step, the anhydrous lithium hydroxide formed in the first step is mixed, overflowed or traversed by a gaseous sulfur source from the group consisting of hydrogen sulfide, elemental sulfur, carbon disulfide, mercaptans or sulfur nitrides.

A compound comprising phosphorus atoms and sulfur atoms as constituent elements and having a peak in Raman spectroscopy, the peak being attributable to a disulfide bond bonding between two phosphorus atoms.

Lithium extractant compounds having the following structure:

##STR00001##

wherein: R.sup.a and R.sup.b are independently selected from the group consisting of hydrocarbon groups (R), —OR, —NRR′, —SR, —SO.sub.2R, —SO.sub.2NR.sub.2, —C(O)R, —C(O)OR, —C(O)NRR′, —C(S)OR, —C(O)SR, and —C(S)NRR′; R′ is selected from R′ groups, wherein R′ is selected from H and R groups; X is O or OH; Y is C or N, wherein, when Y is N, then R.sup.a is R. Also described are hydrophobic water-insoluble solutions containing at least one extractant compound of Formula (1). Also described is a method for extracting lithium from an aqueous solution by contacting the aqueous solution with the hydrophobic solution, and optional stripping of lithium from the hydrophobic solution by contacting the hydrophobic solution with an aqueous stripping solution.

Lithium extractant compounds having the following structure:

##STR00001##

wherein: R.sup.a and R.sup.b are independently selected from the group consisting of hydrocarbon groups (R), —OR, —NRR′, —SR, —SO.sub.2R, —SO.sub.2NR.sub.2, —C(O)R, —C(O)OR, —C(O)NRR′, —C(S)OR, —C(O)SR, and —C(S)NRR′; R′ is selected from R′ groups, wherein R′ is selected from H and R groups; X is O or OH; Y is C or N, wherein, when Y is N, then R.sup.a is R. Also described are hydrophobic water-insoluble solutions containing at least one extractant compound of Formula (1). Also described is a method for extracting lithium from an aqueous solution by contacting the aqueous solution with the hydrophobic solution, and optional stripping of lithium from the hydrophobic solution by contacting the hydrophobic solution with an aqueous stripping solution.

A main object of the present disclosure is to provide a sulfide solid electrolyte with high ion conductivity. In the present disclosure, the above object is achieved by providing a sulfide solid electrolyte comprising: a Li element, an M element (M is at least one kind of P, Ge, Si and Sn), and a S element, and the sulfide solid electrolyte has an argyrodite type crystal phase, in .sup.31P-MAS-NMR, the sulfide solid electrolyte has peak A at 82.1 ppm±0.5 ppm and peak B at 86.1 ppm±0.5 ppm, and when an area ratio of the peak A is regarded as S.sub.A, and an area ratio of the peak B is regarded as S.sub.B, a proportion of the S.sub.B to the S.sub.A, that is S.sub.B/S.sub.A, is 0.23 or less.

A lithium ion conductive material has a composition formula of Li.sub.a(OH).sub.bF.sub.cCl.sub.dBr.sub.1-d, where 1.8≤a≤2.3, b=a −c−1, 0<c≤0.30, 0<d<1, and includes an antiperovskite-type crystal phase. The lithium ion conductive material is manufactured, for example, by heating LiOH, LiF, LiCl, and LiBr at a temperature not lower than 250° C. and not higher than 600° C. for 0.1 hours or more while stirring them at a molar ratio of 1:X:Y:Z (where 0.03≤X≤0.3, 0.2≤Y<1.1, 0<Z<1) under an Ar gas atmosphere.

The positive electrode active material of the present disclosure includes a complex oxide represented by formula (1): LiNi.sub.xMe.sub.1-xO.sub.2 as a main component and has a hydrogen element content of 238.8 ppm by mass or less. Here, x satisfies 0.5≤x≤1, and Me is at least one element selected from the group consisting of Mn, Co, and Al.

This invention relates to treated geothermal brine compositions containing reduced concentrations of lithium, iron and silica compared to the untreated brines. Exemplary compositions contain concentration of lithium ranges from 0 to 200 mg/kg, concentration of silica ranges from 0 to 30 mg/kg, concentration of iron ranges from 0 to 300 mg/kg. Exemplary compositions also contain reduced concentrations of elements like arsenic, barium, and lead.

This invention relates to treated geothermal brine compositions containing reduced concentrations of lithium, iron and silica compared to the untreated brines. Exemplary compositions contain concentration of lithium ranges from 0 to 200 mg/kg, concentration of silica ranges from 0 to 30 mg/kg, concentration of iron ranges from 0 to 300 mg/kg. Exemplary compositions also contain reduced concentrations of elements like arsenic, barium, and lead.