In one embodiment, a positive electrode active material for a secondary battery, the positive electrode active material being a primary particle having a monolithic structure that includes a lithium composite metal oxide of Formula 1 below, wherein the primary particle has an average particle size (D.sub.50) of 2 μm to 20 μm and a Brunauer-Emmett-Teller (BET) specific surface area of 0.15 m.sup.2/g to 0.5 m.sup.2/g, and wherein the positive electrode active material has a rolling density of 3.0 g/cc or higher under a pressure of 2 ton.Math.f:
Li.sub.aNi.sub.1-x-yCo.sub.xM1.sub.yM3.sub.zM2.sub.wO.sub.2  [Formula 1] in Formula 1, M1 is at least one selected from the group consisting of Al and Mn, M2 is any one or two or more elements selected from the group consisting of Zr, Ti, Mg, Ta, and Nb, M3 is any one or two or more elements selected from the group consisting of W, Mo, and Cr, and 1.0≤a≤1.5, 0≤x≤0.5, 0≤y≤0.5, 0.005≤z≤0.01, 0≤w≤0.04, 0<x+y≤0.7.

The present application discloses a lithium ion secondary battery comprising a positive electrode plate, a negative electrode plate, a separator and an electrolyte, wherein the positive electrode plate comprises a positive electrode current collector and a positive electrode film provided on at least one surface of the positive electrode current collector, and the positive electrode film comprises a first positive electrode active material represented by chemical formula Li.sub.1+xNi.sub.aCo.sub.bMe.sub.1-a-bO.sub.2-yA.sub.y and a second positive electrode active material represented by chemical formula Li.sub.1+zMn.sub.cN.sub.2-cO.sub.4-dB.sub.d; the positive electrode plate has a resistivity r of 3500 Ω.Math.m or less; and the electrolyte comprises a fluorine-containing lithium salt type additive. The lithium ion secondary battery provided by the present application is capable of satisfying high safety performance, high-temperature storage performance and cycle performance simultaneously.

The present invention relates to a positive electrode active material and a lithium secondary battery comprising the same.

The present invention relates to a positive electrode active material and a lithium secondary battery comprising the same.

A lithium metal oxide (LMO) cathode includes a current collector having a length defining a first end and a second end, a width, and a first side and a second side, LMO active material applied to the first side and the second side of the current collector such that the LMO active material applied to each respective side of the current collector has an inner face contiguous with the current collector and an outer face, and a plurality of channels extending widthwise across the cathode within the LMO active material applied to the first and second sides. The LMO active material on each current collector side can have a thickness of about 100 μm to about 400 μm. The channels on the same side of the current collector can be spaced apart by 0.1 mm to 10 mm. The channels can have widths of 10 μm to 60 μm.

A lithium metal oxide (LMO) cathode includes a current collector having a length defining a first end and a second end, a width, and a first side and a second side, LMO active material applied to the first side and the second side of the current collector such that the LMO active material applied to each respective side of the current collector has an inner face contiguous with the current collector and an outer face, and a plurality of channels extending widthwise across the cathode within the LMO active material applied to the first and second sides. The LMO active material on each current collector side can have a thickness of about 100 μm to about 400 μm. The channels on the same side of the current collector can be spaced apart by 0.1 mm to 10 mm. The channels can have widths of 10 μm to 60 μm.

A lithium cobalt-based oxide cathode active material powder having: —a primary phase comprising Li, Co, and O, and —a secondary phase comprising LiNaSO.sub.4, wherein the content of said LiNaSO.sub.4 secondary phase in said powder is of at least 0.4 wt. % and inferior or equal to 1.1 wt. % with respect to a total weight of the cathode active material powder, said cathode active material powder being characterized in that it has a S/Na atomic ratio superior or equal to 0.80 and inferior or equal to 1.20.

A secondary battery with excellent cycle performance is provided. The secondary battery is an all-solid-state battery including a positive electrode current collector layer, a base film, a positive electrode active material layer, a buffer layer, and a solid electrolyte layer. The base film contains titanium nitride. The positive electrode active material layer contains lithium cobalt oxide. The buffer layer contains titanium oxide. The solid electrolyte layer contains a titanium compound. By using titanium oxide for the buffer layer, a side reaction between the positive electrode active material layer and the solid electrolyte layer can be suppressed, and cycle performance can be improved.

A secondary battery with excellent cycle performance is provided. The secondary battery is an all-solid-state battery including a positive electrode current collector layer, a base film, a positive electrode active material layer, a buffer layer, and a solid electrolyte layer. The base film contains titanium nitride. The positive electrode active material layer contains lithium cobalt oxide. The buffer layer contains titanium oxide. The solid electrolyte layer contains a titanium compound. By using titanium oxide for the buffer layer, a side reaction between the positive electrode active material layer and the solid electrolyte layer can be suppressed, and cycle performance can be improved.

A secondary battery with favorable cycle performance is provided. Alternatively, a secondary battery with higher capacity is provided. A positive electrode active material layer including a first graphene layer, a second graphene layer, and a positive electrode active material. The first graphene layer includes a first region covering the positive electrode active material. The second graphene layer includes a second region covering the positive electrode active material and a third region overlapping with the first region. The first region includes a plane positioned between the positive electrode active material and the third region and formed of arranged six-membered carbon rings. The positive electrode active material includes a fourth region with a layered rock-salt structure. A lithium layer with a layered rock-salt structure included in the fourth region is substantially perpendicular to the plane formed of six-membered carbon rings and included in the second region.