Positive electrode material for lithium battery, preparing method thereof and lithium battery

1. A preparing method of a positive electrode material for lithium ion battery, comprising the following steps:

a) mixing a manganese-containing compound with a solvent to obtain a solution of the manganese-containing compound;

b) adding a precipitant to the solution of the manganese-containing compound obtained from the step a) to form a precipitate, the precipitant being alkali metal hydroxide solution, alkali metal carbonate solution or alkali metal bicarbonate solution;

c) calcining the precipitate obtained from the step b) to give a positive electrode material precursor;

d) mixing the positive electrode material precursor obtained from the step (c), MnS and a lithium-containing compound, then calcining and grinding to obtain a solid powder; and

e) subjecting the solid powder obtained from the step d) to annealing treatment to give the positive electrode material for lithium ion battery,

wherein the positive electrode material for lithium ion battery has an atomic composition represented by formula (I) and has a crystal structure of cubic spinel of FD-3m:

Li a (M x Mn 2-x )(O 4-y Z y )  (I);

wherein 0.8≤a≤1.2, 0≤x≤1, 0≤y≤1;

M is one or more selected from the group consisting of Li, Na, K, Ca, Mg, Al, Ti, Sc, Ge, V, Cr, Zr, Co, Ni, Zn, Cu, La, Ce, Mn, Hf, Nb, Ta, Mo, W, Ru, Ag, Sn, Pb, and Si; and

Z is one or more selected from the group consisting of OH, halogen, N, P, S and O;

wherein MnS is used as a crystal face modifier for modifying the crystal shape of the obtained positive electrode material;

wherein in the step d), the molar ratio of MnS to the lithium element in the lithium-containing compound is (0.001-0.1):(0.8-1.2), in the step c), the calcining temperature is 300 to 800° C., and the calcining time is 1 to 10 h, in the step d), the calcining temperature is 750 to 1200° C., and the calcining time is 1 to 48 h, and in the step e), the annealing temperature is 400 to 800° C., and the annealing time is 1 to 12 h.

2. A preparing method according to claim 1 , characterized in that the step a) specifically comprises:

mixing a manganese-containing compound with a displacer in a solvent to obtain a solution of the manganese-containing compound, the displacer being one or more selected from the group consisting of a Li-containing compound, a Na-containing compound, a K-containing compound, a Ca-containing compound, a Mg-containing compound, a Al-containing compound, a Ti-containing compound, a Sc-containing compound, a Ge-containing compound, a V-containing compound, a Cr-containing compound, a Zr-containing compound, a Co-containing compound, a Ni-containing compound, a Zn-containing compound, a Cu-containing compound, a La-containing compound, a Ce-containing compound, a Mn-containing compound, a Hf-containing compound, a Nb-containing compound, a Ta-containing compound, a Mo-containing compound, a W-containing compound, a Ru-containing compound, a Ag-containing compound, a Sn-containing compound, a Pb-containing compound, and a Si-containing compound.

3. A preparing method according to claim 2 , characterized in that the manganese-containing compound is one or more selected from the group consisting of manganese sulfate, manganese carbonate, manganese nitrate, manganese chloride, and manganese oxalate.

4. A preparing method according to claim 2 , characterized in that the solvent is water, methanol, ethanol or acetone.

5. A preparing method according to claim 1 , characterized in that the step b) specifically comprises:

adding a precipitant to the solution of the manganese-containing compound obtained from the step a) and regulating pH value to 6 to 13 to give a precipitate.

6. A preparing method according to claim 1 , characterized in that the lithium-containing compound in the step d) is one or more selected from the group consisting of lithium hydroxide, lithium carbonate, lithium nitrate, lithium oxalate, lithium chloride and lithium fluoride.