Powder and lithium nickel mixed metal oxide
Disclosed is a powder comprising a lithium-containing compound and a nickel-containing mixed metal compound, and satisfying the following requirements of (1) and (2) when the powder is analyzed by plasma emission spectrometry of particles: (1) an absolute deviation of a synchronous distribution chart against an approximated straight-line is 0.10 or less, wherein the approximated straight-line is evaluated from a synchronous distribution chart obtained by plotting an emission intensity of lithium and an emission intensity of nickel of each particle composing of the powder, and (2) a release rate of lithium evaluated by the following formula is 80 or less: Release rate of lithium=( n b /n a )×100 wherein, n a is the number of particles containing lithium in the powder, and n b is the number of particles containing lithium and not containing nickel in the powder.
1. A powder comprising a lithium-containing compound and a nickel-containing mixed metal hydroxide and satisfying the following requirements of (1) and (2) when the powder is analyzed by plasma emission spectrometry of particles:
(1) an absolute deviation of a synchronous distribution chart against an approximated straight-line is 0.10 or less, wherein the approximated straight-line is evaluated from a synchronous distribution chart obtained by plotting an emission intensity of lithium and an emission intensity of nickel of each particle composing of the powder, and
(2) a release rate of lithium evaluated by the following formula is 80 or less:
Release rate of lithium=( n b /n a )×100
wherein, n a is the number of particles containing lithium in the powder, and n b is the number of particles containing lithium and not containing nickel in the powder.
2. The powder according to claim 1 , wherein the nickel-containing mixed metal hydroxide further contains, in addition to nickel, at least one transition metal element selected from the group consisting of cobalt, manganese and iron, and the molar ratio of nickel with respect to all transition metal elements in the nickel-containing mixed metal hydroxide is 0.3 or more and 0.9 or less.
3. The powder according to claim 2 , wherein the molar ratio of lithium with respect to all transition metal elements in the nickel-containing mixed metal hydroxide is 0.9 or more and 1.3 or less.
4. The powder according to claim 1 , wherein the lithium-containing compound is lithium hydroxide.
5. A lithium nickel mixed metal oxide obtained by calcining the powder according to claim 1 at a temperature in the range of 650° C. or more and 1050° C. or less.
6. The lithium nickel mixed metal oxide according to claim 5 , which has a bulk density of from 2.0 to 3.5 g/cm 3 .
7. An electrode comprising the lithium nickel mixed metal oxide according to claim 5 .
8. A nonaqueous electrolyte secondary battery comprising a positive electrode, a negative electrode, and an electrolyte, wherein the positive electrode is the electrode according to claim 7 .
9. The nonaqueous electrolyte secondary battery according to claim 8 , further comprising a separator.
10. The nonaqueous electrolyte secondary battery according to claim 9 , wherein the separator is composed of a laminated film which has a porous film and a heat resistant porous layer laminated thereon.