A mixed powder for an all-solid-state lithium-ion battery, which is composed of a positive electrode active material for a lithium-ion battery and a solid electrolyte, wherein the positive electrode active material for a lithium-ion battery is composed of particles containing crystals of a lithium metal composite oxide, and the lithium metal composite oxide has a layered structure and contains at least Li and a transition metal, wherein the positive electrode active material for a lithium-ion battery has a particle diameter distribution that satisfies the following Formula (1), and wherein the solid electrolyte has a particle diameter distribution that satisfies the following Formula (2):

[00001]$\left(\text{D90-D10}\right)/\text{D50}\le \text{1}\text{.5}$

[00002]$\left(\text{D90-D10}\right)/\text{D50}\le 2.0$

What is claimed is 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 lithium metal composite oxide has a layered structure and contains at least Li and a transition metal, and wherein, in the particles, in pore physical properties obtained from nitrogen adsorption isotherm measurement and nitrogen desorption isotherm measurement at a liquid nitrogen temperature, the total pore volume obtained from a nitrogen adsorption amount when the relative pressure (p/p.sub.0) of an adsorption isotherm is 0.99 is less than 0.0035 cm.sup.3/g.

Secondary batteries using lithium cobalt oxide as positive electrode active materials have a problem of a decrease in battery capacity due to repeated charging/discharging, for example. A positive electrode active material particle which hardly deteriorates is provided. In a first step, a container in which a lithium oxide and a fluoride are set is placed in a heating furnace, and in a second step, the inside of the heating furnace is heated in an atmosphere containing oxygen. The heating temperature of the second step is from 750° C. to 950° C., inclusive. By the manufacturing method, fluorine can be contained in the positive electrode active material particle to increase the wettability of the surface of the positive electrode active material so that the surface of the positive electrode active material is homogenized and planarized. The crystal structure of the thus manufactured positive electrode active material is unlikely to be broken in repeated high-voltage charging/discharging. Thus, secondary batteries using the positive electrode active material having such a feature have greatly improved cycle characteristics.

A secondary battery includes a positive electrode, a negative electrode, and an electrolytic solution. The positive electrode includes a positive electrode active material layer. The positive electrode active material layer includes a lithium-nickel composite oxide of a layered rock-salt type.

Disclosed are a transition metal precursor for preparation of a lithium transition metal oxide, in which a ratio of tap density of the precursor to average particle diameter D50 of the precursor satisfies the condition represented by Equation 1 below, and a lithium transition metal oxide prepared using the same. $\begin{array}{cc}0<\frac{\mathrm{Tap}\mathrm{density}}{\begin{array}{c}\mathrm{Average}\mathrm{particle}\mathrm{diameter}D50\\ \mathrm{of}\mathrm{transition}\mathrm{of}\mathrm{metal}\mathrm{precursor}\end{array}}<3500\left(g/\mathrm{cc}.Math.\mathrm{cm}\right)& \left(1\right)\end{array}$

A lithium metal composite oxide having a layered structure, including at least lithium and an element X, wherein:the element X is at least one element selected from the group consisting of Co, Mn, Fe, Cu, Ti, Mg, Al, W, Mo, Nb, Zn, Sn, Zr, Ga, V, B, Si, S and P; the lithium metal composite oxide contains single particles and satisfies all of requirements (1) to (5):(1): a volume-based 50% cumulative particle size D.sub.50 of the lithium metal composite oxide is 2 μm or more and 10 μm or less; (2): the single particles have, on at least a part of surfaces thereof, adhered fine particles, with the proviso that a maximum particle size of the adhered fine particles is smaller than a particle size of the single particles; (3): the particle size of the single particles is 0.2 to 1.5 times D.sub.50 of the lithium metal composite oxide; (4): a particle size of the adhered fine particles is 0.01 to 0.1 times the D.sub.50 of the lithium metal composite oxide; and (5): an average number of the adhered fine particles adhered per particle of the single particles is 1 or more and 30 or less as measured with respect to a range observable in an image obtained by scanning electron microscope.

Embodiments of the present invention relate to a cathode active material, a method for manufacturing the same, and a lithium secondary battery including the same.

According to an embodiment, a cathode active material can be provided, the cathode active material comprising: a lithium metal oxide including a core and a shell disposed on a surface of the core; and a coating layer disposed on a surface of the lithium metal oxide, wherein a c value that satisfies Equation 1 and is in a range of 0.3 to 0.7, and the core and the shell have a layered crystalline structure.

c=b/a  [Equation 1]

(in Equation 1, a is a peak at 530 to 533 eV and b is a peak at 528 to 531 eV in an XPS spectrum of the coating layer)

The present exemplary embodiments relate to a positive electrode active material and a lithium secondary battery including the same. The positive active material for a lithium secondary battery according to an exemplary embodiment includes lithium metal oxide particles including lithium, nickel, cobalt, manganese and doping elements, and includes a first domain and a second domain inside the lithium metal oxide particles.

The present exemplary embodiments relate to a positive electrode active material, a manufacturing method thereof, and a lithium secondary battery including the same. A positive active material for a lithium secondary battery according to an exemplary embodiment is a lithium metal oxide particle in the form of secondary particles including a plurality of primary particles: a first coating layer positioned on at least a part of the surface of the primary particle, and a second coating layer positioned over at least a portion of the secondary particle surface, the first coating layer comprising a first niobium compound, the second coating layer comprising the first niobium compound and a second niobium compound having a composition different from the first niobium compound.

A positive-electrode active material contains a lithium composite oxide containing at least one selected from the group consisting of F, Cl, N, and S. The crystal structure of the lithium composite oxide belongs to a space group C2/m. An XRD pattern of the lithium composite oxide comprises a first peak within the first range of 44 degrees to 46 degrees of a diffraction angle 2θ and a second peak within the second range of 18 degrees to 20 degrees of the diffraction angle 2θ. The ratio of the second integrated intensity of the second peak to the first integrated intensity of the first peak is within a range of 0.05 to 0.90.