A secondary battery includes a positive electrode, a negative electrode including a negative electrode active material, and an electrolytic solution. The negative electrode active material includes a lithium-silicon-containing oxide that includes lithium and silicon as constituent elements and includes magnesium present on a surface layer of the lithium-silicon-containing oxide. The lithium-silicon-containing oxide includes a phase including silicon and a phase including at least one kind of lithium silicate represented by Formula (1). A range in which magnesium is present is within a range of greater than or equal to 10 nm and less than or equal to 3000 nm from a surface of the lithium-silicon-containing oxide in a depth direction. Magnesium forms at least one kind of magnesium silicate represented by Formula (2). A ratio of a number of moles of magnesium to a number of moles of lithium is greater than or equal to 0.1 mol % and less than or equal to 20 mol %,

Li.sub.aSi.sub.bO.sub.c  (1) where a, b, and c satisfy 1≤a≤6, 1≤b≤3, and 1≤c≤7, respectively,

Mg.sub.xSi.sub.yO.sub.z  (2) where x, y, and z satisfy 1≤x≤3, 1≤y≤2, and 1≤z≤4, respectively.

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.

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.

Provided are a positive active material for a lithium secondary battery, a method of preparing the positive active material, a positive electrode for a lithium secondary battery including the positive active material, and a lithium secondary battery including a positive electrode including the positive active material, in which the positive active material may include a nickel-based lithium metal oxide secondary particle including a plurality of large primary particles, the nickel-based lithium metal oxide secondary particle may have a hollow structure having a pore inside, a size of each of the large primary particles may be in a range of about 2 micrometers (μm) to about 6 μm, and a size of the nickel-based lithium metal oxide secondary particle may be in a range of about 10 μm to about 18 μm.

Provided are a positive active material for a lithium secondary battery, a method of preparing the positive active material, a positive electrode for a lithium secondary battery including the positive active material, and a lithium secondary battery including a positive electrode including the positive active material, in which the positive active material may include a nickel-based lithium metal oxide secondary particle including a plurality of large primary particles, the nickel-based lithium metal oxide secondary particle may have a hollow structure having a pore inside, a size of each of the large primary particles may be in a range of about 2 micrometers (μm) to about 6 μm, and a size of the nickel-based lithium metal oxide secondary particle may be in a range of about 10 μm to about 18 μm.

A process for the recovery of lithium from waste lithium ion batteries or parts thereof is disclosed. The process comprising the steps of A) providing a crude lithium hydroxide as a solid, which contains fluoride; and (B) dissolving the crude lithium hydroxide solid with a lower alcohol such as methanol or ethanol provides good separation of lithium in high purity.

In a method for recovering an active metal of a lithium secondary battery according to an embodiment, a waste cathode active material mixture is prepared from a waste cathode of a lithium secondary battery. A preliminary precursor mixture is formed by reacting the waste cathode active material mixture with a reactive gas in a fluidized bed reactor. The preliminary precursor mixture is cooled by spraying different first and second refrigerants to the preliminary precursor mixture. A lithium precursor is recovered from the cooled preliminary precursor mixture.

A fluidized bed reactor according to an embodiment of the present disclosure includes a reactor body, and a dispersion plate coupled to a bottom portion of the reactor body. The dispersion plate may include a base plate and injection columns protruding from a top surface of the base plate. The injection columns include first injection columns arranged at a central portion of the dispersion plate, and second injection columns arranged at a peripheral portion of the dispersion plate. The second injection column has a greater height than a height of the first injection column. A reactive gas is uniformly injected to a wall surface of the reactor through the dispersion plate, thereby increasing a recovery ratio for an active metal of a lithium secondary battery.

A Li ion conductor having a composition different from a conventional composition is provided. The Li ion conductor contains at least one selected from a group Q consisting of Ga, V, and Al, Li, La and O. A part of an Li site is optionally substituted with a metal element D, a part of an La site is optionally substituted with a metal element E, and parts of Ga, V and Al sites are optionally substituted with a metal element J. A mole ratio of an amount of Li to a total amount of La, the element E, Ga, V, Al, and the element J is not lower than 8.1/5 and not higher than 9.5/5. A mole ratio of a total amount of Ga, V, and Al to a total amount of La and the element E is not lower than 1.1/3 and not higher than 2/3.

A Li ion conductor having a composition different from a conventional composition is provided. The Li ion conductor contains at least one selected from a group Q consisting of Ga, V, and Al, Li, La and O. A part of an Li site is optionally substituted with a metal element D, a part of an La site is optionally substituted with a metal element E, and parts of Ga, V and Al sites are optionally substituted with a metal element J. A mole ratio of an amount of Li to a total amount of La, the element E, Ga, V, Al, and the element J is not lower than 8.1/5 and not higher than 9.5/5. A mole ratio of a total amount of Ga, V, and Al to a total amount of La and the element E is not lower than 1.1/3 and not higher than 2/3.