A sulfide solid electrolyte to be used in a lithium-ion secondary battery, including: a crystal phase; and an anion existing in a crystal structure of the crystal phase, in which the crystal phase includes an argyrodite crystal containing Li, P, S, and Ha; Ha is at least one element selected from the group consisting of F, Cl, Br, and I; the anion includes an oxide anion having a Q0 structure having an M-O bond that is a bond of M and O; and M is at least one element selected from the group consisting of metal elements and semimetal elements belonging to Groups 2 to 14 of a periodic table.

Sodium-based all solid-state batteries exhibit improved battery cycle life and stability with the use of a new chloride-based sodium solid electrolyte in which sodium diffusivity within the electrolyte is enhanced through substitution of atoms including one or more of Y with Zr, Ti, Hf, Ta, and Na with one or more of Ca and Sr.

A sacrificial positive electrode material, a positive electrode comprising the same, and a lithium secondary battery having the positive electrode are disclosed herein. In some embodiments, a sacrificial positive electrode material includes a lithium cobalt oxide represented by the following Chemical Formula 1, wherein the sacrificial positive electrode active material has a defect formation energy of metal (M) of −4.0 to −8.5 eV, calculated using density functional theory (DFT):

Li.sub.xCo.sub.(1-y)M.sub.yO.sub.4   [Chemical Formula 1]

M is at least one selected from the group consisting of Al, Fe, Zn, Ti, W, Mg, Ge and Si, pa x and y are 5≤x≤7 and 0.05≤y≤0.6. When the defect formation energy of the metal is controlled within a specific range, a high initial charging/discharging efficiency is realized during initial charging/discharging, and the amount of gas additionally generated at the later time of charging/discharging is reduced. Thus, stability and the charging/discharging performance of a battery is improved.

This positive electrode active material for nonaqueous electrolyte secondary batteries contains: a lithium transition metal composite oxide having secondary particles, each of which is formed of aggregated primary particles; and a surface modification layer which is formed on the surface of each primary particle of the lithium transition metal composite oxide. The lithium transition metal composite oxide contains at least Al and 80% by mole or more of Ni relative to the total number of moles of the metal elements excluding Li; and the surface modification layer contains at least Ba, and at least one of Sr and Ca.

A positive electrode active material for an all-solid-state lithium-ion battery composed of particles containing crystals of a lithium metal composite oxide, wherein the particles have a layered structure and contain at least Li and a transition metal, and in powder x-ray diffraction measurement using CuKα rays, a ratio I.sub.003/I.sub.004 of an integrated intensity I.sub.104 of a diffraction peak in a range of 2θ=44.4±1° to an integrated intensity I.sub.003 of a diffraction peak in a range of 2θ=18.5±1° exceeds 1.23, and wherein a press density A when the positive electrode active material for an all-solid-state lithium-ion battery is compressed at a pressure of 45 MPa is 2.90 g/cm.sup.3 or more.

Described herein are low or no-cobalt materials useful as electrode active materials in a cathode for lithium or lithium-ion batteries. For example, compositions of matter are described herein, such as electrode active materials that can be incorporated into an electrode, such as a cathode. The disclosed electrode active materials exhibit high specific energy and voltage, and can also exhibit high rate capability and/or long operational lifetime.

Provided are a ferroelectric material and an electronic device including same, the ferroelectric material including: a first domain including a first polarization layer which is polarized in a first direction and a first spacer layer disposed adjacent to the first polarization layer; a second domain including a second polarization layer which is polarized in a second direction distinct from the first direction and a second spacer layer disposed adjacent to the second polarization layer; and a structural layer, which is disposed at a domain wall between the first domain and the second domain, and belongs to/has atoms arranged according to a Pbcn space group.

One aspect of the present invention is a positive active material that contains an oxide containing lithium, a transition metal element and a typical element, and having an antifluorite crystal structure, in which the transition metal element is cobalt, iron, copper, manganese, nickel, chromium, or a combination thereof, the typical element is a group 13 element, a group 14 element, phosphorus, antimony, bismuth, tellurium or a combination thereof, and a molar ratio of a content of the typical element to a total content of the transition metal element and the typical element in the oxide is more than 0.05 and 0.5 or less.

Provided is a novel solid electrolyte material of high density and high ionic conductivity, and an all-solid-state lithium ion secondary battery that utilizes the solid electrolyte material. The solid electrolyte material has a chemical composition represented by Li.sub.7-3xGa.sub.xLa.sub.3Zr.sub.2O.sub.12 (0.08≤x<0.5), has a relative density of 99% or higher, belongs to space group I-43d, in the cubic system, and has a garnet-type structure. The lithium ion conductivity of the solid electrolyte material is 2.0×10.sup.−3 S/cm or higher. The solid electrolyte material has a lattice constant a such that 1.29 nm≤a≤1.30 nm, and lithium ions occupy the 12a site, the 12b site and two types of 48e site, and gallium occupies the 12a site and the 12b site, in the crystal structure. The all-solid-state lithium ion secondary battery has a positive electrode, a negative electrode, and a solid electrolyte. The solid electrolyte is made up of the solid electrolyte material of the present invention.

A method for separating a transition metal from a waste positive electrode material includes step 1 of preparing a waste positive electrode material represented by Formula 1, step 2 of heat treating the waste positive electrode material in an inert gas atmosphere or an oxygen atmosphere to phase separate the waste positive electrode material into a lithium oxide and a metal oxide, step 3 of cooling an obtained product of step 2 to room temperature in an inert atmosphere, and step 4 of mixing a cooled product cooled to room temperature in step 3 with distilled water, and then filtering the mixture to leach a transition metal.