A method for synthesizing solid-state electrolytes and for synthesizing precursors for solid-state electrolytes by plasma-processing.

The positive electrode active material of the present disclosure includes a complex oxide represented by a formula (1): LiNi.sub.xMe.sub.1-xO.sub.2 as a main component and contains water in an amount of 2.9 ppm by mass or more and 44.7 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.

The present application relates to novel mixed compounds based on oxides and sulfides, and the use thereof as a solid electrolyte, with improved sulfide stability. The application further relates to electrochemical elements and lithium batteries containing such electrolytes.

The present application relates to novel mixed compounds based on oxides and sulfides, and the use thereof as a solid electrolyte, with improved sulfide stability. The application further relates to electrochemical elements and lithium batteries containing such electrolytes.

This disclosure relates to the manufacture an alkali metal quaternary crystalline nanomaterial. an alkali metal quaternary crystalline nanomaterial having general Formula A (I.sub.2-II-IV-VI.sub.4); and wherein I is sodium (Na) or lithium (Li), II and IV are Zn or Sn, and VI is a chalcogens selected from the group comprising: sulphur (S), selenium (Se) or tellurium (Te). The crystal phase of the alkali metal quaternary crystalline nanomaterial may be a primitive mixed Cu—Au like structure (PMCA) and may have a space group: P42m. The nanomaterials may be adapted to provide a solar cell. Methods of manufacture are also provided.

The method of manufacturing a sulfide-based inorganic solid electrolyte material, including: (A) preparing a sulfide-based inorganic solid electrolyte material in a vitreous state; and (B) annealing the sulfide-based inorganic solid electrolyte material in the vitreous state using a heating unit. Step (B) includes a step (B1) of disposing the sulfide-based inorganic solid electrolyte material in the vitreous state in a heating space, a step (B2) of annealing the sulfide-based inorganic solid electrolyte material in the vitreous state disposed in the heating space while increasing a temperature of the heating unit from an initial temperature T.sub.0 to an annealing temperature T.sub.1, and a step (B3) of annealing the sulfide-based inorganic solid electrolyte material in the vitreous state disposed in the heating space at the annealing temperature T.sub.1, and a temperature increase rate from the initial temperature T.sub.0 to the annealing temperature T.sub.1 in the step (B2) is 2° C./min or higher.

The method of manufacturing a sulfide-based inorganic solid electrolyte material, including: (A) preparing a sulfide-based inorganic solid electrolyte material in a vitreous state; and (B) annealing the sulfide-based inorganic solid electrolyte material in the vitreous state using a heating unit. Step (B) includes a step (B1) of disposing the sulfide-based inorganic solid electrolyte material in the vitreous state in a heating space, a step (B2) of annealing the sulfide-based inorganic solid electrolyte material in the vitreous state disposed in the heating space while increasing a temperature of the heating unit from an initial temperature T.sub.0 to an annealing temperature T.sub.1, and a step (B3) of annealing the sulfide-based inorganic solid electrolyte material in the vitreous state disposed in the heating space at the annealing temperature T.sub.1, and a temperature increase rate from the initial temperature T.sub.0 to the annealing temperature T.sub.1 in the step (B2) is 2° C./min or higher.

A sulfide solid electrolyte contains a compound that has a crystal phase having an argyrodite-type crystal structure and that is represented by Li.sub.aPS.sub.bX.sub.c, where X is at least one elemental halogen, a represents a number of 3.0 or more and 6.0 or less, b represents a number of 3.5 or more and 4.8 or less, and c represents a number of 0.1 or more and 3.0 or less. The sulfide solid electrolyte has a ratio of A.sub.Li/(A.sub.Li+A.sub.P+A.sub.S+A.sub.X) to a specific surface area (m.sup.2 g.sup.−1) of 3.40 (m.sup.−2g) or more, where A.sub.Li represents the amount of lithium (atom %) quantitatively determined from the Li 1s peak, A.sub.P represents the amount of phosphorus (atom %) quantitatively determined from the P 2p peak, A.sub.S represents the amount of sulfur (atom %) quantitatively determined from the S 2p peak, and A.sub.X represents the amount of halogen (atom %) quantitatively determined from the halogen peak, the peaks being exhibited in X-ray photoelectron spectroscopy (XPS).

A method for producing a sulfide solid electrolyte includes: preparing a uniform solution that includes at least elemental lithium (Li), elemental tin (Sn), elemental phosphorus (P), and elemental sulfur (S) in an organic solvent; removing the organic solvent from the uniform solution to obtain a precursor; and heat-treating the precursor to obtain a sulfide solid electrolyte.

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.