Transition Metal Precursor Having Low Tap Density And Lithium Transition Metal Oxide Having High Particle Strength
Disclosed are a lithium transition metal oxide and a lithium secondary battery, in which a ratio of average particle diameter D50 of the lithium transition metal oxide to average particle diameter D50 of a transition metal precursor for preparation of the lithium transition metal oxide satisfies the condition represented by Equation 3 below: 0 < Average particle diameter D 50 of lithium transition metal oxide Average particle diameter D 50 of transition metal precursor < 1.2 . ( 3 )
1 . A lithium transition metal oxide in which a ratio of average particle diameter D50 of the lithium transition metal oxide to average particle diameter D50 of a transition metal precursor for preparation of the lithium transition metal oxide satisfies the condition represented by Equation 3 below:
0
<
Average
particle
diameter
D50
of
lithium
transition
metal
oxide
Aaverage
particle
diameter
D50
of
transition
metal
precursor
<
1.2
.
(
3
)
2 . The lithium transition metal oxide according to claim 1 , wherein the lithium transition metal oxide comprises Ni, Mn and Co.
3 . The lithium transition metal oxide according to claim 2 , wherein the lithium transition metal oxide is a compound represented by Formula 4 below:
Li a Ni x Mn y Co z M w O 2-t A t (4)
wherein 0<a≤1.2, 0<x≤0.9, 0<y≤0.9, 0<z≤0.9, 0≤w≤0.3, 2≤a+x+y+z+w≤2.3, and 0≤t<0.2;
M is at least one metal cation selected from Al, Cu, Fe, Mg, B, Cr, or transition metals of 2 period in the Periodic Table of the Elements; and
A is at least one monovalent or divalent anion.
4 . The lithium transition metal oxide according to claim 3 , wherein, in Formula 4, x>y and x>z.
5 . The lithium transition metal oxide according to claim 1 , wherein the transition metal precursor consists of transition metal hydroxide particles represented by Formula 2 below:
NiCoMn(OH 1-x ) 2 (2)
wherein 0≤x≤0.5; and
wherein a tap density of the transition metal precursor is from 1.3 g/cc to 1.6 g/cc, and a ratio of tap density to average particle diameter D50 of the precursor satisfies a condition represented by Equation 1 below:
2000
<
Tap
density
Average
particle
diameter
D50
of
transition
metal
precursor
<
3500
(
g
/
cc
·
cm
)
.
(
1
)
6 . The lithium transition metal oxide according to claim 5 , wherein the transition metal precursor has an average particle diameter D50 of 1 to 30 μm.
7 . A lithium secondary battery in which a unit cell comprising a positive electrode comprising the lithium transition metal oxide according to claim 1 , a negative electrode, and a polymer membrane disposed between the positive electrode and the negative electrode is accommodated in a battery case.