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 disclosure relates to a method of manufacturing an anode active material for a lithium secondary battery, the method including: mixing earth graphite and pitch coke with each other; preparing a raw material by adding and mixing a binder to the mixture; performing heat treatment on the raw material; graphitizing the heat-treated mixture to obtain a core part; immersing the core part in a hard carbon coating solution; and drying the coating solution in which the core part is immersed to obtain an anode active material.

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.

This electrode for nonaqueous electrolyte secondary batteries is provided with a collector, an active material layer that is formed on the collector, and an assembly of filler particles, said assembly being present on the surface of the active material layer. The filler particles contain at least one of boron oxide, potassium pyrosulfate and a compound containing an alkali metal or Br, while having a transformation point, at which the filler particles undergo a transformation from a solid phase to a liquid phase or a thermal decomposition, within the range of from 180° C. to 650° C. The compound containing an alkali metal or Br contains at least one of a borate, a silicate, a carbonate, a hydrogen carbonate, a citrate or an aromatic compound.

A positive electrode active material for an all-solid-state lithium ion secondary battery, containing: a lithium-metal composite oxide particle having a niobium solid solution layer and a center other than the niobium solid solution layer; and a coating layer coating at least a part of a surface of the lithium-metal composite oxide particle and formed of a compound containing lithium and niobium, an average thickness of the coating layer is 2 nm or more and 1 μm or less, and an average thickness of the niobium solid solution layer is 0.5 nm or more and 20 nm or less.

An electrochemical device, including a positive electrode. The positive electrode includes a positive current collector and a positive active material layer. The positive active material layer includes particles A and particles B. A circularity of a particle A is R.sub.A, a cross-sectional area of the particle A is S.sub.A, a circularity of a particle B is R.sub.B, a cross-sectional area of the particle B is S.sub.B, where R.sub.B<0.4≤R.sub.A and S.sub.B<20 μm.sup.2≤S.sub.A. Based on a total area of a cross section of the positive electrode in a direction perpendicular to the positive current collector, a ratio of a total area percent of the particles A to a total area percent of the particles B is 1:9 to 8:2. The electrochemical device exhibits excellent electrochemical performance, especially reduces the amount of generated gas and improves cycle stability of the electrochemical device.

A negative electrode material includes silicon composite particles. The silicon composite particles include amorphous silicon particles and a buffer phase. The amorphous silicon particles are dispersed in the buffer phase. A non-uniformity of the amorphous silicon particles dispersed in the buffer phase is less than or equal to 30%. Also, an electronic device including the negative electrode material.

A negative electrode plate includes: a current collector; and a negative electrode framework located on the current collector, where the negative electrode framework includes at least a first negative electrode framework layer and a second negative electrode framework layer, the first negative electrode framework layer is located between the current collector and the second negative electrode framework layer, and a porosity of the first negative electrode framework layer is higher than a porosity of the second negative electrode framework layer. With this design, side reactions between lithium metal and an electrolyte can be reduced, formation of lithium dendrites can be inhibited, and drastic swelling and contraction of the negative electrode plate in volume due to intercalation and deintercalation of lithium ions can be greatly alleviated or even eliminated, thereby improving safety and stability of the electrochemical apparatus.