Cathode active material for secondary battery, method of manufacturing the same, and cathode for lithium secondary battery including the cathode active material

Abstract

The present invention relates to a cathode active material including a lithium-containing transition metal oxide and two or more metal composite oxide layers selected from the group consisting of Chemical Formulae 1 to 3 which are coated on the surface of the lithium-containing transition metal oxide, a method of manufacturing the same, and a cathode for a secondary battery including the cathode active material,M(C2H5O2)n  [Chemical Formula 1]M(C6H(8-n)O7)  [Chemical Formula 2]M(C6H(8-n)O7)(C2H5O2)  [Chemical Formula 3](where M, as a metal desorbed from a metal precursor, represents at least one metal selected from the group consisting of Mg, Ca, Sr, Ba, Y, Ti, Zr, V, Nb, Ta, Cr, Mo, W, Mn, Fe, Co, Ir, Ni, Zn, Al, Ga, In, Si, Ge, Sn, La, and Ce, and n is an integer between 1 and 4).

Description

TECHNICAL FIELD[0001]The present invention relates to a cathode active material for a secondary battery, a method of manufacturing the same, and a cathode for a lithium secondary battery including the cathode active material, and more particularly, to a cathode active material uniformly coated with two or more metal composite oxide layers, a method of manufacturing the same, and a cathode for a lithium secondary battery including the cathode active material.BACKGROUND ART[0002]In line with the increasing use of mobile devices and vehicles, demand for secondary batteries as their energy sources has been rapidly increased. As the secondary batteries, lithium secondary batteries having high energy density, high voltage, long cycle life, and low self-discharging rate have been commercialized and widely used.[0003]A lithium secondary battery may be largely composed of a cathode active material, an anode active material, a separator, and an electrolyte. Specifically, a carbon material has...

AI Technical Summary

Benefits of technology

[0016]According to a method of the present invention, a cathode active material having improved conductivity and density may be manufactured by including two or more metal composite oxide layers that are coated to a uniform thickness. Also, a secondary battery having improved cycle characteristics may be prepared by including the cathode active material.

Problems solved by technology

With respect to LiCoO2 which has currently been most widely used among the above cathode active materials due to excellent life characteristics and charge and discharge efficiency, it has limitations in being applied to high-capacity batteries for electric vehicles due to the fact that it has low structural stability, has high raw material costs, and causes environmental pollution.

With respect to a lithium manganese oxide, such as LiMnO2 and LiMn2O4, studied as an alternative material of LiCoO2, it is inexpensive, but has disadvantages in that electrical conductivity is low, capacity is low, and electrode degradation rapidly occurs at high temperature.

Also, with respect to the lithium-containing nickel oxide, it has battery characteristics of high discharge capacity, but has disadvantages in that it is difficult to be synthesized by a simple solid-state reaction and its cycle characteristics are low.

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