Method of preparing material for lithium secondary battery of high performance

摘要

Provided is a method for preparing a lithium mixed transition metal oxide, comprising subjecting Li2CO3 and a mixed transition metal precursor to a solid-state reaction under an oxygen-deficient atmosphere with an oxygen concentration of 10 to 50% to thereby prepare a powdered lithium mixed transition metal oxide having a composition represented by Formula I of LixMyO2 wherein M, x and y are as defined in the specification. Therefore, since the high-Ni lithium mixed transition metal oxide having a given composition can be prepared by a simple solid-state reaction in air, using a raw material that is cheap and easy to handle, the present invention enables industrial-scale production of the lithium mixed transition metal oxide with significantly decreased production costs and high production efficiency. Further, the thus-produced lithium mixed transition metal oxide is substantially free of impurities, and therefore can exert a high capacity and excellent cycle stability, in conjunction with significantly improved storage stability and high-temperature stability.

主权项

1. A method for preparing a lithium mixed transition metal oxide, comprising subjecting Li2CO3 and a mixed transition metal precursor to a solid-state reaction under an oxygen-deficient atmosphere having an oxygen concentration of 10 to 50% by volume to thereby prepare a powdered lithium mixed transition metal oxide having a composition represented by Formula I:
LixMyO2  (I) wherein: M=M′1−kAk, wherein M′ is Ni1−a−b(Ni1/2Mn1/2)aCob, 0.65≦a+b≦0.85 and 0.1≦b≦0.4; A is a dopant; 0≦k<0.05; and x+y=2 and 0.95≦x≦1.05, wherein the mixed transition metal precursor has a tap density of 1.1 to 1.6 g/cm3.