Metal oxide and method for preparing the same
This application relates to a metal oxide and a method for preparing the same. Specifically, Co 3 O 4 is selected as a precursor of lithium cobalt oxide, and one or more metal elements M are doped in the particles of Co 3 O 4 to obtain a doped lithium cobalt oxide precursor Co 3-x M x O 4 , where 0<x≤0.3. The difference value, measured by a spectrometer of a scanning electron microscope, of the weight percentage of one of M in two identical area regions is E, wherein 0<E≤1% (wt. %). A lithium ion battery with lithium cobalt oxide prepared from the precursor as a cathode material shows great cycle stability, high-temperature energy storage performance and safety performance in a high-voltage (equal to or greater than 4.45 V) charging and discharging environment.
1. A metal oxide, having the general formula of Co 3-x M x O 4 , wherein 0<x≤0.3,
M is one or more metal elements, and
a difference value, measured by an energy spectrometer of a scanning electron microscopy, of the weight percentage of one of M in two identical area regions is E, wherein 0<E≤1% (wt. %),
wherein M comprises at least one of Al, Mg, Ti, Zr, Ni, Mn, Y, Sc, V, Cr, Ga, Nb, Mo, In, Ce, Pr, Er, Yb, Lu, or W.
2. The metal oxide according to claim 1 , wherein an average valence of M in the metal oxide is A, and +2≤A≤+3.5.
3. The metal oxide according to claim 1 , wherein the average valence of M in the metal oxide is A, and A is +3.0.
4. The metal oxide according to claim 1 , wherein when M is only one metal element, M is only an element with the valence of +2 or +3.
5. The metal oxide according to claim 1 , wherein when M is a plurality of metal elements and the valence of each metal element is +2 or +3, the molar content ratio of the metal elements is an arbitrary value.
6. The metal oxide according to claim 1 , wherein when M is a plurality of metal elements, the valence of some metal elements is +3 and the valence of the other metal elements is greater than +3, the molar content of the metal elements with the valence of +3 is 50% or more of the total molar content of doping metal elements.
7. The metal oxide according to claim 1 , wherein the metal oxide is of a single phase structure.
8. The metal oxide according to claim 1 , wherein the metal oxide is of a tetragonal spinel crystal structure.
9. The metal oxide according to claim 1 , wherein the metal oxide has no diffraction peak at a scattering angle smaller than the diffraction peak corresponding to a Miller index (111).
10. The metal oxide according to claim 1 , wherein the integrated intensity of the diffraction peak of a Miller index (311) of the metal oxide is greater than the integrated intensity of the diffraction peak of a Miller index (400).
11. The metal oxide according to claim 1 , wherein the metal oxide is used as a precursor for preparing lithium cobalt oxide as a cathode material of a lithium ion battery.
12. A lithium cobalt oxide composite prepared from the metal oxide according to claim 1 , wherein the general formula is Li a Co 1-y M y N b O 2+c ,
0.99<a<1.05, 0<y≤0.1, 0≤b≤0.1, 0≤c<0.2,
N is metal element, and N is distributed on the surface layer of the lithium cobalt oxide composite, and
M is one or more metal elements.
13. The lithium cobalt oxide composite according to claim 12 , wherein N comprises at least one of Al, Mg, Ti, Zr, Ni, Mn, Y, La or Sm.
14. The lithium cobalt oxide compound according to claim 12 , wherein M comprises at least one of Al, Mg, Ti, Zr, Ni, Mn, Y, Sc, V, Cr, Ga, Nb, Mo, In, Ce, Pr, Er, Yb, Lu or W.
15. A lithium ion battery, comprising a cathode, an anode, a separator and an electrolyte, wherein the cathode comprises the lithium cobalt oxide composite prepared from the metal oxide according to claim 1 .
16. A method for preparing a metal oxide, wherein the method comprises the following steps:
mixing and reacting a solution of an M-containing compound, a solution of a Co-containing compound and an alkali solution to obtain a precipitation material; and
sintering the precipitation material at 500-1000° C. for 4-12 h to obtain the metal oxide, the general formula of the metal oxide being Co 3-x M x O 4 , wherein
0<x≤0.3,
M is one or more metal elements, and
the difference value, measured by the energy spectrometer of the scanning electron microscopy, of the weight percentage of one of M in two identical area regions is E, wherein 0<E≤1% (wt. %).
17. The method according to claim 16 , wherein the M-containing compound comprises at least one of nitrate, oxalate, acetate, sulfate, fluoride or chloride of M.
18. The method according to claim 16 , wherein the molar concentration of M in the solution of the M-containing compound is 0.01-5 mol/L.
19. The method according to claim 16 , wherein in the mixing and reacting step, the pH value of the mixed solution is 6-9.