Layered core-shell cathode active materials for lithium secondary batteries, method for preparing thereof and lithium secondary batteries using the same

Abstract

Disclosed herein is a layered core-shell cathode active material for secondary lithium batteries, in which the core layer has a structural formula of Li1+a[MxMn1-x]2O4 (M is selected from a group consisting of Ni, Co, Mg, Zn, Ca, Sr, Cu, Zr, P, Fe, Al, Ga, In, Cr, Ge, Sn and combinations thereof, 0.01=x=0.25, O=a=O.l) and the shell layer has a structural formula of Li1+a[M'yMn1-y]2O4 (M' is selected from a group consisting of Ni, Mg, Cu, Zn and combinations thereof, 0.01=y=0.5, O=a=O.l). hi the layered cathode active material, the core layer, corresponding to a 4V spinel-type manganese cathode, functions to increase the capacity of the active material while the shell layer, corresponding to a 5 V spinel-type transition metal mix-based cathode, is electrochemically stable enough to prevent the reaction of the components with electrolytes and the dissolution of transition metals in electrolytes, thereby improving thermal and lifetime characteristics of the active material.

Description

technical field [0001] The present invention relates generally to secondary lithium batteries, and more particularly, to layered core-shell cathode active materials for secondary lithium batteries. Background technique [0002] Since Sony Corporation commercialized lithium ion secondary battery packs in 1991, such secondary battery packs have been used as portable energy sources in various portable electric appliances. With the great progress in the fields of electronics, communication and computer industries, high-performance electronic and communication products, such as mobile phones, camcorders, and laptop computers, have been developed based in part on the available lithium-ion secondary battery packs as energy sources. Wait. In addition, in advanced countries such as the United States, Japan, and European countries, active research has been conducted on energy sources for hybrid vehicles, in which internal combustion engines and lithium-ion secondary batteries, especi...

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Problems solved by technology

However, the manganese carbonate crystals thus obtained are not spherical but irregular in shape with a wide particle size distribution

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