Detailed Description
The invention provides a preparation method of a positive electrode material and a positive electrode material prepared by the preparation method, and the preparation method of the positive electrode material and the positive electrode material prepared by the preparation method are explained in more detail below.
A preparation method of a positive electrode material comprises the following steps:
A. mixing and sintering a first lithium source and a doped cobalt source to obtain a material A;
B. mixing a second lithium source, a nickel-manganese-cobalt ternary precursor and nickel oxide, and sintering to obtain a material B;
C. mixing and sintering the material A, the material B and the coating agent;
wherein, the doping elements of the doped cobalt source comprise Sb and at least one of Mg, Al, Ti and Zr, and the cladding agent comprises nickel oxide and at least one of aluminum oxide, lanthanum oxide and yttrium oxide.
It should be noted that, the step a and the step B are not sequentially divided, the doping of the cobalt source may be mixing a doping element with the cobalt source, sintering at 750-920 ℃ for 1-2h after ball milling, the doping element of the cobalt source may be Mg and Sb, Al and Sb, Ti and Sb, Zr and Sb or Mg, Al, Ti and Sb, the cladding agent may be alumina and nickel oxide, lanthanum oxide and nickel oxide, yttrium oxide and nickel oxide or alumina, lanthanum oxide and nickel oxide, and the proportion of nickel, manganese and cobalt in the nickel, manganese and cobalt ternary precursor may be 424, 333, 523, 701 or 515.
Preferably, the step A also comprises grinding the material A to obtain a powder with the particle size D50 of 10-25 μm; and step B, grinding the material B to obtain the material D50 with the particle size of 3-8 μm. The material A with larger particles and the material B with smaller particles are mixed according to a certain proportion, so that the pole piece compaction density of the anode material can be improved, the advantages of the anode material and the cathode material can be highlighted, and the anode material has higher specific capacity, better cycle performance and lower cost. Specifically, the A material is pulverized to obtain particle sizes D50 of 10 μm, 15 μm and 25 μm, and the B material is pulverized to obtain particle sizes D50 of 3 μm, 4 μm and 8 μm.
Preferably, in step A, the cobalt source includes but is not limited to one or more of cobaltosic oxide, cobalt hydroxide and cobalt hydroxide, the molar ratio of Li to Co is 1.03-1.2, and the sintering temperature is 950-1100 ℃. The cobalt source is preferably one or a mixture of more of tricobalt tetraoxide, cobalt hydroxide and cobalt hydroxide, but the choice of cobalt source is not limited to these materials. Specifically, the molar ratio of Li to Co may be 1.03, 1.07, or 1.2, and the sintering temperature may be 950 ℃, 1000 ℃, or 1100 ℃.
Preferably, in the step A, the doping amount of Sb is 0.02-0.5% of the mole number of Co, and the doping amount of one or more of Mg, Al, Ti and Zr is 0.02-0.5% of the mole number of Co. Specifically, the doping amount of Sb is 0.02%, 0.2%, 0.3%, or 0.5% of the mole number of Co, and the doping amount of one or more of Mg, Al, Ti, and Zr is 0.02%, 0.2%, 0.3%, or 0.5% of the mole number of Co.
Preferably, in the step B, the molar ratio of Li to (Ni + Co + Mn) is 1.03-1.2, and the nickel oxide accounts for 3-7% of the weight of the nickel-cobalt-manganese ternary precursor. The nickel oxide is preferably nano-scale, specifically, the molar ratio of Li to (Ni + Co + Mn) can be 1.03, 1.1 or 1.2, and the nickel oxide accounts for 3%, 4% or 7% of the weight of the nickel-cobalt-manganese ternary precursor.
Preferably, in the step C, the weight ratio of the material A to the material B is (60-90): (40-10), and the sintering temperature is 800-950 ℃. Specifically, the weight ratio of the material A to the material B can be 60:40, 90:10, 90:40 or 60:10, and the like, and the sintering temperature can be 800 ℃, 880 ℃ or 950 DEG C
Preferably, in the step C, the weight ratio of the coating agent to the material A is 0.05-1%, and the sintering temperature is 850-. Specifically, the weight ratio of the coating agent to the material A can be 0.05%, 0.8% or 1%, and the sintering temperature can be 850 ℃, 900 ℃ or 950 ℃.
Preferably, the first lithium source is selected from one or more of lithium carbonate, lithium fluoride, lithium hydroxide and lithium acetate, and the second lithium source is selected from one or more of lithium carbonate, lithium fluoride, lithium hydroxide and lithium acetate. The first lithium source and the second lithium source may be selected to be the same or different, and the selection of the first lithium source and the second lithium source is not limited to these materials.
Preferably, the step C treatment further comprises a crushing and screening treatment.
The cathode material prepared by the preparation method of the cathode material.
In order to make the objects, technical solutions and effects of the present invention clearer and clearer, the present invention is described in further detail below with reference to examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
Example 1
A preparation method of a positive electrode material comprises the following steps:
A. doping Sb and Zr with cobaltosic oxide, mixing the Sb and Zr with lithium carbonate, and sintering to obtain a material A;
B. mixing and sintering lithium carbonate, a nickel-manganese-cobalt ternary precursor and nickel oxide to obtain a material B;
C. mixing the material A, the material B, yttrium oxide and nickel oxide, and sintering.
Example 2
A preparation method of a positive electrode material comprises the following steps:
A. doping Sb and Mg with cobaltosic oxide, uniformly mixing the Sb and Mg with lithium carbonate, sintering the mixture at 1030 ℃ for 2 hours, cooling the mixture, and performing ball milling on the mixture to obtain a material A with the particle size D50 of 25 mu m;
B. uniformly mixing a ternary precursor of lithium carbonate, nickel manganese cobalt (523) and nano nickel oxide, sintering at 900 ℃ for 10 hours, cooling, and ball-milling to obtain a material B with the particle size D50 of 8 mu m;
C. uniformly mixing the material A, the material B, nickel oxide and aluminum oxide, preserving heat for 8 hours at the temperature of 900 ℃, cooling, crushing and screening;
in the step A, the doping amounts of Sb and Mg are respectively 0.1 percent and 0.15 percent of the mole number of Co, and the cobaltosic oxide raw material is mixed according to the molar ratio of Li to Co of 1.05; in the step B, lithium carbonate, a nickel-cobalt-manganese (523) ternary precursor and a nano nickel oxide raw material are mixed according to the molar ratio of Li to (Ni + Co + Mn) of 1.05, wherein the weight of the nickel oxide accounts for 5% of that of the nickel-cobalt-manganese (523) ternary precursor; in the step C, the weight ratio of the material A to the material B is 80:20, and the weight ratio of the coating agent to the material A is 1%.
Example 3
A preparation method of a positive electrode material comprises the following steps:
A. doping Sb, Al and Mg with hydroxyl cobalt, uniformly mixing with lithium hydroxide, sintering at 950 ℃ for 2.5h, cooling, and ball-milling into a material A with the particle size D50 of 20 mu m;
B. uniformly mixing a ternary precursor of lithium hydroxide, nickel manganese cobalt (523) and nano nickel oxide, sintering at 900 ℃ for 10 hours, cooling, and ball-milling to obtain a material B with the particle size D50 of 5 mu m;
C. uniformly mixing the material A, the material B, nickel oxide and aluminum oxide, preserving heat for 6 hours at 950 ℃, cooling, crushing and screening;
in the step A, the doping amount of Sb is 0.5 percent of the mole number of Co, the doping amounts of Al and Mg are 0.5 percent of the mole number of Co, and the hydroxy cobalt raw material is prepared according to the molar ratio of Li to Co of 1.2; in the step B, the lithium hydroxide, the nickel-cobalt-manganese (523) ternary precursor and the nano nickel oxide raw material are mixed according to the molar ratio of Li to (Ni + Co + Mn) of 1.2, wherein the weight of the nickel oxide accounts for 7 percent of that of the nickel-cobalt-manganese (523) ternary precursor; in the step C, the weight ratio of the material A to the material B is 90:10, and the weight ratio of the coating agent to the material A is 0.05%.
Example 4
A preparation method of a positive electrode material comprises the following steps:
A. doping Sb and Zr with cobaltosic oxide, uniformly mixing the Sb and Zr with lithium carbonate, sintering the mixture at 1000 ℃ for 2 hours, cooling the mixture, and performing ball milling on the cooled mixture to obtain a material A with the particle size D50 of 20 mu m;
B. uniformly mixing a ternary precursor of lithium carbonate, nickel manganese cobalt (523) and nano nickel oxide, sintering at 900 ℃ for 10 hours, cooling, and ball-milling to obtain a material B with the particle size D50 of 5 mu m;
C. uniformly mixing the material A, the material B, nickel oxide and lanthanum oxide, preserving heat for 6 hours at the temperature of 900 ℃, cooling, crushing and screening;
in the step A, the doping amount of Sb is 0.3 percent of the mole number of Co, the doping amount of Zr is 0.4 percent of the mole number of Co, and the cobaltosic oxide raw material is mixed according to the mole ratio of Li to Co of 1.08; in the step B, lithium carbonate, a nickel-cobalt-manganese (523) ternary precursor and a nano nickel oxide raw material are mixed according to the molar ratio of Li to (Ni + Co + Mn) of 1.15, wherein the weight of the nickel oxide accounts for 6% of that of the nickel-cobalt-manganese (523) ternary precursor; in the step C, the weight ratio of the material A to the material B is 90:20, and the weight ratio of the coating agent to the material A is 0.08%.
Example 5
A preparation method of a positive electrode material comprises the following steps:
A. doping Sb and Ti with cobalt hydroxide, mixing the mixture with lithium fluoride uniformly, sintering the mixture at 1100 ℃ for 2 hours, cooling the mixture, and performing ball milling on the cooled mixture to obtain a material A with the particle size D50 of 10 mu m;
B. uniformly mixing a ternary precursor of lithium carbonate, nickel manganese cobalt (523) and nano nickel oxide, sintering at 800 ℃ for 11 hours, cooling, and ball-milling to obtain a material B with the particle size D50 of 3 mu m;
C. uniformly mixing the material A, the material B, nickel oxide and yttrium oxide, preserving the heat for 8 hours at the temperature of 800 ℃, cooling, crushing and screening;
in the step A, the doping amount of Sb is 0.02 percent of the mole number of Co, the doping amount of Ti is 0.02 percent of the mole number of Co, and cobalt hydroxide raw materials are mixed according to the mole ratio of Li to Co of 1.03; in the step B, lithium carbonate, a nickel-cobalt-manganese (523) ternary precursor and a nano nickel oxide raw material are mixed according to the molar ratio of Li to (Ni + Co + Mn) of 1.03, wherein the weight of the nickel oxide accounts for 3% of that of the nickel-cobalt-manganese (523) ternary precursor; in the step C, the weight ratio of the material A to the material B is 60:40, and the weight ratio of the coating agent to the material A is 1%.
Example 6
A preparation method of a positive electrode material comprises the following steps:
A. doping Sb, Mg, Al, Ti and Zr with cobaltosic oxide, uniformly mixing with lithium acetate, sintering at 950 ℃ for 3h, cooling, and ball-milling into a material A with the particle size D50 of 15 mu m;
B. uniformly mixing a ternary precursor of lithium carbonate, nickel manganese cobalt (523) and nano nickel oxide, sintering at 850 ℃ for 10h, cooling, and ball-milling to obtain a material B with the particle size D50 of 7 mu m;
C. uniformly mixing the material A, the material B, nickel oxide, aluminum oxide, lanthanum oxide and yttrium oxide, preserving heat for 6 hours at 950 ℃, cooling, crushing and screening;
in the step A, the doping amount of Sb is 0.2 percent of the mole number of Co, the doping amounts of Mg, Al, Ti and Zr are 0.3 percent of the mole number of Co, and the cobaltosic oxide raw material is prepared according to the mole ratio of Li to Co of 1.1; in the step B, lithium carbonate, a nickel-cobalt-manganese (523) ternary precursor and a nano nickel oxide raw material are mixed according to the molar ratio of Li to (Ni + Co + Mn) of 1.1, wherein the weight of the nickel oxide accounts for 5% of that of the nickel-cobalt-manganese (523) ternary precursor; in the step C, the weight ratio of the material A to the material B is 70:40, and the weight ratio of the coating agent to the material A is 1%.
Comparative example 1
A preparation method of a positive electrode material comprises the following steps:
A. uniformly mixing cobaltosic oxide with lithium carbonate, sintering at 1030 ℃ for 2h, cooling, and ball-milling to obtain a material A with the particle size D50 of 25 mu m;
B. uniformly mixing a ternary precursor of lithium carbonate, nickel manganese cobalt (523) and nano nickel oxide, sintering at 900 ℃ for 10 hours, cooling, and ball-milling to obtain a material B with the particle size D50 of 8 mu m;
C. uniformly mixing the material A, the material B, nickel oxide and aluminum oxide, preserving heat for 8 hours at the temperature of 900 ℃, cooling, crushing and screening;
wherein, in the step A, the cobaltosic oxide raw material is mixed according to the molar ratio of Li to Co of 1.05; in the step B, lithium carbonate, a nickel-cobalt-manganese (523) ternary precursor and a nano nickel oxide raw material are mixed according to the molar ratio of Li to (Ni + Co + Mn) of 1.05, wherein the weight of the nickel oxide accounts for 5% of that of the nickel-cobalt-manganese (523) ternary precursor; in the step C, the weight ratio of the material A to the material B is 80:20, and the weight ratio of the coating agent to the material A is 1%.
Comparative example 2
A preparation method of a positive electrode material comprises the following steps:
A. doping Sb and Mg with cobaltosic oxide, uniformly mixing the Sb and Mg with lithium carbonate, sintering the mixture at 1030 ℃ for 2 hours, cooling the mixture, and performing ball milling on the mixture to obtain a material A with the particle size D50 of 25 mu m;
B. uniformly mixing lithium carbonate and a ternary nickel manganese cobalt (523) precursor, sintering at 900 ℃ for 10 hours, cooling, and ball-milling to obtain a material B with the particle size D50 of 8 mu m;
C. uniformly mixing the material A, the material B, nickel oxide and aluminum oxide, preserving heat for 8 hours at the temperature of 900 ℃, cooling, crushing and screening;
in the step A, the doping amounts of Sb and Mg are respectively 0.1 percent and 0.15 percent of the mole number of Co, and the cobaltosic oxide raw material is mixed according to the molar ratio of Li to Co of 1.05; in the step B, lithium carbonate and nickel cobalt manganese (523) ternary precursor raw materials are mixed according to the molar ratio of Li to (Ni + Co + Mn) of 1.05; in the step C, the weight ratio of the material A to the material B is 80:20, and the weight ratio of the coating agent to the material A is 1%.
Comparative example 3
A preparation method of a positive electrode material comprises the following steps:
A. doping Sb and Mg with cobaltosic oxide, uniformly mixing the Sb and Mg with lithium carbonate, sintering the mixture at 1030 ℃ for 2 hours, cooling the mixture, and performing ball milling on the mixture to obtain a material A with the particle size D50 of 25 mu m;
B. uniformly mixing a ternary precursor of lithium carbonate, nickel manganese cobalt (523) and nano nickel oxide, sintering at 900 ℃ for 10 hours, cooling, and ball-milling to obtain a material B with the particle size D50 of 8 mu m;
C. uniformly mixing the material A and the material B, preserving heat for 8 hours at the temperature of 900 ℃, cooling, crushing and screening;
in the step A, the doping amounts of Sb and Mg are respectively 0.1 percent and 0.15 percent of the mole number of Co, and the cobaltosic oxide raw material is mixed according to the molar ratio of Li to Co of 1.05; in the step B, lithium carbonate, a nickel-cobalt-manganese (523) ternary precursor and a nano nickel oxide raw material are mixed according to the molar ratio of Li to (Ni + Co + Mn) of 1.05, wherein the weight of the nickel oxide accounts for 5% of that of the nickel-cobalt-manganese (523) ternary precursor; in the step C, the weight ratio of the material A to the material B is 80: 20.
The positive electrode materials prepared according to the positive electrode material preparation methods of examples 1 to 6 and comparative examples 1 to 3 were used as full cells and examined, and the examination results are shown in tables 1 to 2:
table 1 examples 1-5 battery performance
Table 2 example 6 and comparative examples 1-3 cell performance
As can be seen from tables 1-2, the full cells prepared in examples 1-6 were much better than comparative examples 1-3 in terms of 1C specific volume, 1C cycle capacity retention rate of 400 weeks, thickness expansion rate measured after storage at 85 ℃ for 4 hours in full electric state and 3C5V overcharge, etc., the examples 1-6 and comparative examples 1-2 were not much different in 135 ℃ heat abuse, and examples 1-6 were much better than comparative example 3 in 135 ℃ heat abuse.
This is because: in examples 1 to 6, a cobalt source is used in step a, nickel oxide is doped in step B, and a coating agent is added in step C, the cobalt source is doped in step a, nickel oxide is doped in step B, and the coating agent is added in step C, these three processing methods are mutually matched, the doping substance and the coating agent are mutually promoted and act together, and the prepared positive electrode material has the advantages of high specific capacity, good cycle performance, small high-temperature storage thickness expansion rate, high energy density, and the like. In the step A in the comparative example 1, a doped cobalt source is not used, only nickel oxide and a coating agent play a role, in the step B in the comparative example 2, nickel oxide is not doped, only the doped cobalt source and the coating agent play a role, in the comparative example 3, the coating agent is added in the step C, only the doped cobalt source and the doped nickel oxide play a role, and in the comparative examples 1-3, the combined action of the three treatment methods is lacked, so that the comprehensive performances of the prepared anode material, such as specific capacity, cycle performance, high-temperature storage performance, energy density and the like, can not reach the optimal state.
It is to be understood that the invention is not limited to the examples described above, but that modifications and variations may be effected thereto by those of ordinary skill in the art in light of the foregoing description, and that all such modifications and variations are intended to be within the scope of the invention as defined by the appended claims.