WO2024016662A1 - 一种正极材料用复合包覆剂、一种高镍单晶正极材料和电池 - Google Patents

一种正极材料用复合包覆剂、一种高镍单晶正极材料和电池 Download PDF

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WO2024016662A1
WO2024016662A1 PCT/CN2023/077793 CN2023077793W WO2024016662A1 WO 2024016662 A1 WO2024016662 A1 WO 2024016662A1 CN 2023077793 W CN2023077793 W CN 2023077793W WO 2024016662 A1 WO2024016662 A1 WO 2024016662A1
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Prior art keywords
coating
coating agent
cathode material
coating element
oxide
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PCT/CN2023/077793
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English (en)
French (fr)
Inventor
李冰冰
屈振昊
刘志远
董沛沛
于建
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宁波容百新能源科技股份有限公司
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Publication of WO2024016662A1 publication Critical patent/WO2024016662A1/zh

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—Composites
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention relates to the technical field of battery materials, and in particular to a composite coating agent for cathode materials, a high-nickel single crystal cathode material and a battery.
  • Lithium-ion battery cathode materials are widely used in research and application.
  • the existing technology CN109713262A discloses a preparation method of cobalt oxide-coated cathode materials. It relates to a preparation method of cobalt oxide-coated cathode material, and belongs to the technical field of battery cathode materials.
  • the problem to be solved is how to achieve low sintering temperature and low coating amount while achieving high rate performance.
  • the method includes putting the cobalt source and high-nickel cathode material into a container, and then stirring and mixing at a rotation speed of ⁇ 700 rpm to obtain the corresponding Mixed materials; in an atmosphere of air or oxygen, perform low-temperature solid-phase sintering of the mixed materials at 250°C to 550°C to obtain the corresponding cobalt oxide-coated cathode material; the coating amount of cobalt oxide is the cathode 0.1wt% ⁇ 1.0wt% of material quality. It can effectively achieve the effect of low cobalt oxide coating and achieve the rate and cycle performance of the material under high pressure conditions.
  • the single cobalt source coating in this document only serves as an isolation layer to alleviate the interface reaction between the material and the electrolyte, reduce the surface impurities of the material, improve the transmission of lithium ions and reduce polarization; while the coating after annealing Cobalt not only generates amorphous cobalt oxide and a small amount of cobalt oxide on the surface of the material, but also generates a poor conductor, cobalt tetroxide, which not only prevents the charge electrolyte from contacting the positive electrode, hinders charge transmission and reduces the conductivity of the material, but also causes coating
  • the layer is uneven and unstable, and there are no measures to solve the Li/Ni mixing inside the high-nickel ternary cathode and alleviate the occurrence of internal and external micro-cracks.
  • Prior art CN112194196A discloses a composite coating agent for ultra-high nickel single crystal ternary cathode material and its preparation method and application. Discloses a composite coating agent for ultra-high nickel single crystal ternary cathode material. The agent and its preparation method and application belong to the technical field of lithium-ion power batteries for new energy vehicles.
  • a composite coating agent for ultra-high nickel single crystal ternary cathode materials including: at least one of metal and/or non-metal oxides, ammonium salt compounds, and solvents, which is produced through ball milling, airflow pulverization, calcination, and wet mixing. , prepared by at least one process of spray drying.
  • the prepared composite coating agent forms a uniform coating layer on the surface of the single crystal material through coating and calcination. It can also reduce the level of residual alkali on the surface and improve the cycle performance and safety performance of the material.
  • this document uses a wet process and adds a wet coating liquid. On the one hand, because the wet process directly washes away the residual lithium on the surface of the material, it does not improve the Li/Ni mixing and Li transmission channels inside the material. In addition, overwashing or insufficient washing in the wet process, and uneven washing will greatly damage the cathode material on the surface of the material, causing uneven material surface and reduced cycle rate performance.
  • wet coating liquid can easily cause the coating agent of the positive electrode material to fall off during the charge and discharge process, and the coating agent cracks, causing direct contact between the electrolyte and the surface of the positive electrode, causing the positive electrode material to
  • the particles of the material are more likely to crack and then break, which will accelerate the corrosion of the cathode active material by the electrolyte, leading to severe capacity reduction and poor cycle performance of the lithium-ion battery.
  • the process is cumbersome and costly, making it unsuitable for large-scale industry. change.
  • the technical problem to be solved by the present invention is to provide a high-nickel single crystal cathode material.
  • the cathode material provided by the present invention has high capacity and good cycle stability.
  • the invention provides a composite coating agent for cathode materials, including a first coating agent, a second coating agent and a third coating agent;
  • the first coating agent is a hydroxide of a first coating element , oxide, sulfide, nitrate or carbonate;
  • the second coating agent is a hydroxide, oxide, sulfide, nitrate or carbonate of the second coating element;
  • the third coating The coating agent is a hydroxide, oxide, sulfide, nitrate or carbonate of the third coating element;
  • the first coating element includes one or more of Ni, Mn, Co and B; the second coating element includes one or more of Mg, Al, Nb, W and Mo; the third coating element Elements include one or more of Ti, Cr, Zr, Y and Sr.
  • the molar ratio of the first coating element, the second coating element and the third coating element is 1-15:0.1-18:0-12.
  • the first coating agent is NiMnCo(OH) 2 , NiMnCoCO 3 , Co(OH) 2 , MnCO 3 , CoCO 3 , H 3 BO 3 , B(NO 3 ) 3 , CoOOH or Mn(OH) At least one of 2 .
  • the second coating agent is MgO, MgCO 3 , Mg(OH) 2 , Al 2 O 3 , Al(OH) 3 , MoO 3 , Mo(OH) 3 , WO 3 , Nb(OH) 5 or at least one of Nb 2 O 5 ;
  • the third coating agent is at least one of TiO, Cr(OH) 2 , ZrO 2 , C 2 O 5 Zr, Y 2 O 3 or Sr(OH) 2 .
  • the invention provides a coating layer, which is characterized in that it is prepared from the coating agent described in any one of the above technical solutions.
  • the invention provides a high-nickel single crystal cathode material, which is characterized in that it includes a cathode material matrix and the coating layer described in the above technical solution provided on the surface of the cathode material matrix.
  • the mole fraction of the coating element in the coating layer in the cathode material matrix is 0.0001 to 8%.
  • the coating layer is composed of lithium-containing coating element oxide and lithium-free coating element oxide.
  • the molar amount of the coating element contained in the oxide containing the lithium coating element accounts for 50% to 89% of the total amount of the coating element.
  • the molar ratio of the first coating element, the second coating element and the third coating element is 29-100:0-71:0-66.
  • the invention provides a method for preparing a high-nickel single crystal cathode material, which includes the following steps:
  • the dopant is selected from TiO, Ti 2 O 3 , Sc 2 O 3 , MgO, K 2 CO 3 , V 2 O 5 , At least one of Cr 2 O 3 , Sb 2 O 3 , Ta 2 O 5 , Y 2 O 3 , Zr 2 O 3 , ZrO 2 , NaBO 2 , WO 3 , MoO 3 , Nb 2 O 5 , etc.;
  • step A) The specific calcination in step A) is: heating to 190-420°C at a heating rate of 1-10°C.min -1 , and holding for 3.5-10.5h; and then raising the temperature to 690-920°C at a rate of 2-4°C.min -1 °C, keep warm for 8 to 11 hours; then cool to room temperature at 2 to 3 °C ⁇ min -1 ;
  • the calcination in step C) specifically involves heating up to 500-810°C at a rate of 3-10°C/min and maintaining the temperature for 9-11 hours.
  • the present invention provides a lithium-ion battery, including the high-nickel single-crystal cathode material described in any one of the above technical solutions or the high-nickel single-crystal cathode material prepared by the preparation method described in any of the above technical solutions.
  • the present invention provides a composite coating agent for cathode materials, including a first coating agent, a second coating agent and a third coating agent; the first coating agent is a first coating agent.
  • the second coating agent is the hydroxide, oxide, sulfide, nitrate or carbonate of the second coating element Salt;
  • the third coating agent is a hydroxide, oxide, sulfide, nitrate or carbonate of the third coating element; wherein the first coating element includes Ni, Mn, Co and B.
  • the second coating element includes one or more of Mg, Al, Nb, W and Mo;
  • the third coating element includes one or more of Ti, Cr, Zr, Y and Sr kind.
  • the composite coating agent in the present invention uses different elements to be compounded on the surface of the cathode material, which reduces the excessive precipitation of Li in the cathode material and thus reduces the formation of residual alkali, alleviates the generation of micro-cracks on the surface of the cathode material, and protects the cathode material from interacting with the electrolyte.
  • the present invention includes
  • the special lithium-containing coating element oxide contained in the coating has a partial energy storage effect and thus improves the capacity and stability of the material.
  • the generated coating element oxide brings thermal stability and good effects on the electrolyte.
  • the protective effect improves the material's cycle stability without damaging the material.
  • the present invention provides a composite coating agent for cathode materials, a high-nickel single crystal cathode material and a battery.
  • a composite coating agent for cathode materials a high-nickel single crystal cathode material and a battery.
  • Persons skilled in the art can learn from the content of this article and appropriately improve the process parameters for implementation.
  • all similar substitutions and modifications will be obvious to those skilled in the art. , they all belong to the protection scope of the present invention.
  • the methods and applications of the present invention have been described through preferred embodiments. Relevant persons can obviously modify or appropriately change and combine the methods and applications herein without departing from the content, spirit and scope of the present invention to implement and apply the present invention.
  • Invent technology is a composite coating agent for cathode materials, a high-nickel single crystal cathode material and a battery.
  • the invention provides a composite coating agent for cathode materials, including a first coating agent, a second coating agent and a third coating agent;
  • the first coating agent is a hydroxide of a first coating element , oxide, sulfide, nitrate or carbonate;
  • the second coating agent is a hydroxide, oxide, sulfide, nitrate or carbonate of the second coating element;
  • the third coating The coating agent is a hydroxide, oxide, sulfide, nitrate or carbonate of the third coating element;
  • the first coating element includes one or more of Ni, Mn, Co and B; the second coating element includes one or more of Mg, Al, Nb, W and Mo; the third coating element Elements include one or more of Ti, Cr, Zr, Y and Sr.
  • the composite coating agent for cathode materials provided by the present invention includes a first coating agent.
  • the first coating agent is a hydroxide, oxide, sulfide, nitrate or carbonate of the first coating element; the first coating element includes Ni, Mn, Co and B. One or several.
  • the first coating agent is NiMnCo(OH) 2 , NiMnCoCO 3 , Co(OH) 2 , MnCO 3 , CoCO 3 , H 3 BO 3 , B(NO 3 ) 3 , CoOOH or Mn(OH) 2 at least one.
  • the composite coating agent for cathode materials provided by the present invention includes a second coating agent.
  • the second coating agent of the present invention is a hydroxide, oxide, sulfide, nitrate or carbonate of the second coating element; the second coating element includes Mg, Al, Nb, W and Mo. One or several.
  • the second coating agent is MgO, MgCO 3 , Mg(OH) 2 , Al 2 O 3 , Al(OH) 3 , MoO 3 , Mo(OH) 3 , WO 3. At least one of Nb(OH) 5 or Nb2O5 .
  • the composite coating agent for cathode materials provided by the present invention includes a third coating agent.
  • the third coating agent of the present invention is a hydroxide, oxide, sulfide, nitrate or carbonate of the third coating element; the third coating element includes Ti, Cr, Zr, Y and Sr. one or several kind.
  • the third coating agent is CrO 3 , TiO, Cr(OH) 2 , ZrO 2 , C 2 O 5 Zr, Y 2 O 3 or Sr(OH) 2 At least one.
  • the composite coating agent of the present invention contains different groups of elements.
  • the combination and proportion of these elements can be used as a coating layer to reduce the excessive precipitation of Li and the formation of residual alkali in the cathode material, generate Li-containing compounds with energy storage effects, and alleviate the occurrence of microcracks on the surface of the cathode material.
  • the invention provides a coating layer prepared from the coating agent described in any one of the above technical solutions.
  • the present invention not only reduces the loss of Li in the material by reacting the first coating agent with Li that is excessively precipitated during the charge and discharge process of the cathode material, but also generates lithium-containing coating element oxides with energy storage functions to prevent excessive precipitation.
  • Li combines with H 2 O and CO 2 to generate Li 2 CO 3 under certain conditions, thus reducing the gas production of high-nickel ternary cathode material batteries.
  • the elements in the second coating agent can react with the electrolyte to generate a solid super acid, which can remove impurities on the surface of the cathode material and improve the charge transfer in the SEI film on the surface of the cathode material and the ion transport in the electrolyte, inhibiting its The resulting increase in surface resistance; on the other hand, the higher thermal stability of the second coating agent can inhibit the generation of oxygen and enhance the electrolyte, ultimately reducing the loss of electrochemical capacity of the ternary cathode material.
  • the elements in the third coating agent will enter the layered structure of the cathode material after coating and form chemical bonds with the oxygen atoms in the crystal lattice to improve the stability of the material, expand the transmission channel of Li, and reduce the Li/ Ni mixed arrangement can effectively alleviate the occurrence of internal strain and structural degradation.
  • the invention provides a high-nickel single crystal cathode material, which includes a cathode material matrix and the coating layer described in the above technical solution provided on the surface of the cathode material matrix.
  • the structural formula of the high-nickel single crystal cathode material of the present invention is Li x Ni a M b N c O 2 /K.
  • K is the cladding layer.
  • the coating layer is prepared from the coating agent described in any one of the above technical solutions; part of the coating agent reacts with lithium to obtain a lithium-containing coating element oxide.
  • the coating layer of the present invention is composed of a lithium-containing coating element oxide and a lithium-free coating element oxide.
  • the first cladding element is marked as K1; the second cladding element is marked as K2; and the third cladding element is marked as K3.
  • the mole fraction of the coating elements in the coating layer of the present invention in the cathode material matrix is preferably 0.0001 to 8%; more preferably, it is 0.1 to 8%;; most preferably, it is 0.19 to 8%;;
  • the mole fraction of the coating elements in the coating layer in the cathode material matrix is 0.016-5.6%; further, it can also be 0.024-0.92%; further, it can be 0.036-0.92%. 0.78%, further, it can also be 0.052 ⁇ 2.7%, further, it can also be 0.078 ⁇ 6.2%, further, it can also be 4.5 ⁇ 7.6%, further, it can also be 3.8 ⁇ 4.8%, further, It can also be 3.5 to 3.9%.
  • the elements K1, K2, and K3 of the present invention exist in the form of lithium-containing coating element oxides and a small amount of lithium-free coating element oxides, and the lithium-containing coating element oxides are located on the surface of the cathode material matrix, which is beneficial to energy storage performance. , the lithium-free coating element oxide is located outside the lithium-containing coating element oxide, which is beneficial to the gas production performance.
  • the coating layer of the present invention is composed of lithium-containing coating element oxide and lithium-free coating element oxide.
  • the lithium-containing coating element oxide of the present invention is an oxide formed from Li in the cathode material and the coating element.
  • the molar ratio of the coating element contained in the lithium-containing coating element oxide to the total amount of coating elements is preferably 50 to 89%, and more preferably 51 to 83%; the molar ratio of the coating element contained in the lithium-containing coating element oxide Yuan The molar ratio of the element to the total amount of coating elements is preferably 11 to 50%.
  • the first coating element is denoted as m1; the second coating element is denoted as m2; and the third coating element is denoted as m3.
  • the mole fraction of the m1 element in the coating element contained in the lithium-containing coating element oxide is 29 to 100%, and the m2 element accounts for the mole fraction of the coating element contained in the lithium-containing coating element oxide.
  • the mole fraction of the element is 0 to 71%, and the mole fraction of the m3 element in the coating element contained in the lithium-containing coating element oxide is 0 to 66%.
  • the positive electrode material since the positive electrode material is more likely to undergo phase change in its near-surface area during contact with the electrolyte, it changes from the original layered structure to a spinel phase and a rock salt phase.
  • the Li ion conductivity of these two structures is relatively high. If low, the transmission of Li ions will be reduced, resulting in increased polarization of the cathode material; and because the coating layer needs to provide a transmission channel for ions and electrons, its unique non-denseness will cause part of the electrolyte to come into contact with the material surface, thereby causing A phase change occurs on the material surface, causing capacity fading of the cathode material.
  • the present invention solves the above problems.
  • the doped elements in the cathode material form chemical bonds with the oxygen atoms in the crystal lattice to improve the stability of the material, expand the transmission channel of Li, reduce Li/Ni mixing, thereby reducing the cost of the cathode material.
  • the formation of NiO rock salt phase on the surface effectively alleviates internal strain and structural degradation;
  • the doped elements in the present invention and the lithium-containing coating element oxide and the lithium-free coating element oxide formed on the surface of the cathode material stabilize the internal structure of the material, protect the material surface from electrolyte erosion, and can Provide a part of the capacity, so the doping and coating measures in the present invention generally greatly improve the cycle performance and thermal stability of the single crystal material.
  • the residual alkali and gas production levels are higher than ordinary single coating modifications. Low, and can increase the overall capacity of the material, obtaining a high-nickel single crystal ternary cathode material with good overall performance.
  • the invention provides a method for preparing a high-nickel single crystal cathode material, which includes the following steps:
  • the preparation method of the high-nickel single crystal cathode material provided by the invention first mixes the ternary precursor and lithium hydroxide monohydrate.
  • the ternary precursor of the present invention is preferably Ni 0.8 Co 0.12 Mn 0.08 (OH) 2 , Ni 0.8 Co 0.1 Mn 0.1 (OH) 2 , Ni 0.8 Co 0.15 Al 0.05 (OH) 2 , Ni 0.82 Co 0.1 Mn 0.08 (OH) 2 , Ni 0.83 Co 0.12 Mn 0.05 (OH) 2 , Ni 0.85 Co 0.05 Mn 0.1 (OH) 2 , Ni 0.85 Co 0.1 Mn 0.05 (OH) 2 , Ni 0.9 Co 0.05 Mn 0.05 (OH) 2 , Ni 0.96 Co 0.02 Mn 0.02 (OH) 2 , Ni 0.98 Co 0.01 Mn 0.01 (OH) 2 .
  • the molar ratio of lithium to the metal in the ternary precursor is 0.8-1.05:1; the present invention does not limit the specific mixing method, which is well known to those skilled in the art.
  • the dopant of the present invention is selected from the group consisting of TiO, Ti 2 O 3 , Sc 2 O 3 , MgO, K 2 CO 3 , V 2 O 5 , Cr 2 O 3 , Sb 2 O 3 , At least one of Ta 2 O 5 , Y 2 O 3 , Zr 2 O 3 , ZrO 2 , NaBO 2 , WO 3 , MoO 3 , Nb 2 O 5 , etc.;
  • the added amount of the dopant in the present invention is preferably 0 to 0.19wt%, 0.0001 to 0.15wt%, 0.00015 to 0.09wt%, 0.0002 to 0.078wt%, and 0.0032 to 0.054wt%.
  • the mole fraction of the doping element in the cathode material matrix is preferably 0.28-0.76%; more preferably 0.32-0.64%; most preferably 0.39-0.64%.
  • the present invention is not limited to the protective atmosphere, and any protective gas well known to those skilled in the art can be used, including but not limited to nitrogen, helium, argon, etc.
  • the calcination is as follows: heating to 190-420°C and holding for 3.5-10.5 hours at a heating rate of 1-10°C ⁇ min -1 ; and then raising the temperature to 690-920°C at a rate of 2-4°C ⁇ min -1 , keep warm for 8 to 11 hours; then cool to room temperature at 2 to 3°C ⁇ min -1 .
  • the calcined material is crushed, iron removed, and sieved to obtain the cathode material matrix.
  • the present invention does not limit the specific operations of crushing, iron removal, and screening, as those skilled in the art are familiar with them.
  • the positive electrode material matrix and the coating agent are mixed and calcined again in the presence of protective gas.
  • the calcination specifically involves raising the temperature to 500-810°C at a rate of 3-10°C/min and maintaining the temperature for 9-11 hours.
  • the present invention does not limit the specific operations of crushing, iron removal, and screening, as those skilled in the art are familiar with them.
  • the present invention provides a lithium-ion battery, including the high-nickel single-crystal cathode material described in any one of the above technical solutions or the high-nickel single-crystal cathode material prepared by the preparation method described in any of the above technical solutions.
  • the present invention adopts a dry coating process. Compared with the wet process, the residual lithium on the surface of the material is directly washed away. It does not improve the Li/Ni mixing and Li transmission channels inside the material, and the wet process has unique characteristics. Overwashing or insufficient washing, uneven washing will cause great damage to the cathode material on the surface of the material, resulting in uneven material surface, reduced cycle rate performance and other problems.
  • the present invention only needs to directly coat the doped cathode material, which fundamentally solves the problem of residual alkali generation without damaging the material. It can obtain a ternary material with good capacity, cycle and rate performance, thereby improving the residual alkali resistance. level.
  • the coating agent in the present invention evenly coats the surface of the material to form dense small particles, which isolates the electrolyte from contact with the positive electrode material and improves the cycle life of the material. If the mass ratio of the composite coating agent and the high-nickel ternary material in the present invention is less than 0.0001%, the coating agent is not enough to completely cover the material surface, and the electrolyte contacts the positive electrode material, causing the coating to fail. If the composite coating If the mass ratio of the agent to the high-nickel ternary material is greater than 8%, the coating layer will be too thick and uneven, resulting in obstruction of lithium ion migration and a decrease in rate and cycle behavior.
  • the coating layer of the present invention protects the positive electrode material from contact with the electrolyte while providing a part of the capacitance, thereby improving the capacity and stability of the positive electrode material, improving the residual lithium on the surface of the positive electrode material and the gas production of the final soft-pack battery, and increasing Improve the safety and stability of the material.
  • the dry process of the present invention reduces a large amount of energy consumption and equipment process losses during the production process, and therefore has the advantage of promoting mass production.
  • the composition of the composite coating agent is H 3 BO 3 and Mo(OH) 3 , where the first coating The molar ratio of element (B), the second coating element (Mo) and the third coating element is 6:1:0. After uniform mixing, it is recorded as composite coating agent 1.
  • the composition of the composite coating agent is CoCO 3 and MgO, where the molar ratio of the first coating element (Co), the second coating element (Mg) and the third coating element is 1:1:0.
  • the molar proportion of the coating agent is 1.6%
  • the ternary precursor is Ni 0.83 Co 0.12 Mn 0.05 (OH) 2
  • the dopant is TiO
  • the molar proportion of the dopant is 0.4%
  • the remaining steps are the same as in Example 1 The same, as shown in Table 1.
  • the composition of the composite coating agent is CoOOH, Al 2 O 3 , and CrO 3 , in which the moles of the first coating element (Co), the second coating element (Al), and the third coating element (Cr)
  • the ratio of _ _ _ The ratio is 0.52%, and the remaining steps are the same as in Example 1, as shown in Table 1.
  • the composition of the composite coating agent is Co(OH) 2 and MoO 3 ; the molar ratio of the first coating element (Co), the second coating element (Mo) and the third coating element is 5: 0.7:0, the molar ratio of the coating agent is 2.66%, the ternary precursor is Ni 0.85 Co 0.05 Mn 0.1 (OH) 2 , the dopants are MgO and Ta 2 O 5 , the molar ratio of the dopant is 0.46%, the remaining steps are the same as Example 1, The details are shown in Table 1.
  • the composition of the composite coating agent in this embodiment is Mn(OH) 2 and Nb 2 O 5 , where the molar ratio of the first coating element (Mn), the second coating element (Nb) and the third coating element is 6:1:0, the molar ratio of the coating agent is 4.91%, the ternary precursor is Ni 0.8 Co 0.1 Mn 0.1 (OH) 2 , the dopants are MoO 3 and NaBO 2 , the molar ratio of the dopant 0.5%, and the remaining steps are the same as in Example 1, as shown in Table 1.
  • the composition of the composite coating agent in this embodiment is NiMnCo(OH) 2 :Nb 2 O 5 :ZrO 2 , where the first coating element (Ni, Mn, Co), the second coating element (Nb) and the third coating element are The molar ratio of the coating element (Zr) is 3:2:1, the molar ratio of the coating agent is 6.76%, the ternary precursor is Ni 0.8 Co 0.1 Mn 0.1 (OH) 2 , and the dopants are ZrO 2 and Cr 2 O 3 , the molar ratio of the dopant is 0.57%, and the remaining steps are the same as in Example 1, as shown in Table 1.
  • the composition of the composite coating agent in this embodiment is B(NO 3 ) 3 and WO 3 ; the molar ratio of the first coating element (B), the second coating element (W) and the third coating element is 6 ⁇ 1:0, the molar ratio of the coating agent is 0.19%, the ternary precursor is Ni 0.9 Co 0.05 Mn 0.05 (OH) 2 , the dopants are MoO 3 , NaBO 2 , TiO, the molar ratio of the dopant The ratio is 0.6%, and the remaining steps are the same as in Example 1, as shown in Table 1.
  • the composition of the composite coating agent in this embodiment is Mn(OH) 2 :Al 2 O 3 :Sr(OH) 2 , in which the first coating element (Mn), the second coating element (Al) and the third coating element are The molar ratio of the coating element (Sr) is 7:1:0.9, the molar ratio of the coating agent is 0.86%, the ternary precursor is Ni 0.96 Co 0.02 Mn 0.02 (OH) 2 , and the dopants are MoO 3 and Zr 2 O 3 , NaBO 2 , the molar ratio of the dopant is 0.64%, and the remaining steps are the same as in Example 1, as shown in Table 1.
  • the composition of the composite coating agent in this embodiment is MnCO 3 : Al 2 O 3 :0, where the molar ratio of the first coating element (Mn), the second coating element (Al) and the third coating element is 5: 1.5:0, the molar ratio of the coating agent is 8.0%, the ternary precursor is Ni 0.9 Co 0.05 Mn 0.05 (OH) 2 , and the dopant is Nb 2 O 5 , the molar ratio of the dopant is 0.62%, and the remaining steps are the same as in Example 1, as shown in Table 1.
  • the composition of the composite coating agent in this embodiment is NiMnCoCO 3 :WO 3 :TiO.
  • the molar ratio of the first coating element (NiMnCo), the second coating element (W) and the third coating element (Ti) is 0.4. ⁇ 1:1.4, the molar ratio of the coating agent is 0.8%, the ternary precursor is Ni 0.8 Co 0.15 Al 0.05 (OH) 2 , the dopants are Ti 2 O 3 , Sc 2 O 3 , MgO, doping
  • the molar proportion of the agent was 0.56%, and the remaining steps were the same as in Example 1, as shown in Table 1.
  • This comparative example does not contain a coating agent.
  • the ternary precursor is Ni 0.83 Co 0.12 Mn 0.05 (OH) 2 .
  • the dopants are Sc 2 O 3 and MgO.
  • the molar ratio of the dopants is 0.57%.
  • This comparative example does not contain a coating agent.
  • the ternary precursor is Ni 0.83 Co 0.12 Mn 0.05 (OH) 2 .
  • the dopants are MoO 3 , Zr 2 O 3 and NaBO 2 .
  • the molar ratio of the dopants is 0.64. %, and the remaining steps are the same as Comparative Example 1, as shown in Table 1.
  • the coating agent is NiCoMnCO 3
  • the molar ratio of the coating agent is 0.2%
  • the ternary precursor is Ni 0.83 Co 0.12 Mn 0.05 (OH) 2
  • dopants dopants.
  • the remaining steps are the same as those in Example 1 The same, as shown in Table 1.
  • the coating agent composition is MnCO 3 and MgO, in which the molar ratio of the first coating element (Mn), the second coating element (Mg) and the third coating element is 1:1:0.
  • the molar ratio of the dopant is 0.4%
  • the ternary precursor is Ni 0.83 Co 0.12 Mn 0.05 (OH) 2 , and does not contain dopants.
  • the remaining steps are the same as in Example 1, as shown in Table 1.
  • the coating agent composition is NiCoMnCO 3 , MgO, Sr(OH) 2 , in which the molar ratio of the first coating element (NiCoMn), the second coating element (Mg) and the third coating element (Sr) is is 1:1:1, the molar ratio of the coating agent is 0.6%, the ternary precursor is Ni 0.83 Co 0.12 Mn 0.05 (OH) 2 , and does not contain dopants.
  • the remaining steps are the same as in Example 1, specifically as follows As shown in Table 1.
  • the composition of the composite coating agent in this comparative example is Co(OH) 2 , WO 3 , and TiO; where the first coating element (Co), the second coating element (W), and the third coating element (Ti)
  • the molar ratio is 0.4:20:1.4, the molar ratio of the coating agent is 6.71%, the ternary precursor is Ni 0.83 Co 0.12 Mn 0.05 (OH) 2 , and the dopants are Ti 2 O 3 , Sc 2 O 3 , MgO, the molar ratio of the dopant was 0.56%, and the remaining steps were the same as in Example 1, as shown in Table 1.
  • the composition of the composite coating agent in this comparative example is MnCO 3 , Al 2 O 3 , Y 2 O 3 , in which the first coating element (Mn), the second coating element (Al) and the third coating element (Y ) is 17:1:0.9, the molar ratio of the coating agent is 4.8%, the ternary precursor is Ni 0.83 Co 0.12 Mn 0.05 (OH) 2 , and the dopants are Sc 2 O 3 and MgO.
  • the molar proportion of the impurity is 0.56%, and the remaining steps are the same as in Example 1, as shown in Table 1.
  • composition of the composite coating agent in this comparative example is Zn(OH) 2 , CaO, Ba(OH) 2 first coating element (Zn), second coating element (Ca) and third coating element (Ba)
  • Zn first coating element
  • Ca second coating element
  • Ba third coating element
  • composition of the composite coating agent in this comparative example is H 3 BO 3 and Mo(OH) 3 ; the molar ratio of the first coating element (B), the second coating element (Mo) and the third coating element is 1 ⁇ 1:0, the molar ratio of the coating agent is 9.9%, the ternary precursor is Ni 0.83 Co 0.12 Mn 0.05 (OH) 2 , the dopants are Ti 2 O 3 and Sc 2 O 3 , the dopant The molar proportion is 0.4%, and the remaining steps are the same as in Example 1, as shown in Table 1.
  • the composition of the composite coating agent in this comparative example is CoCO 3 and MgO; the molar ratio of the first coating element (Co), the second coating element (Mg) and the third coating element is 6:0.7:0.
  • the molar proportion of the coating agent is 8.8%, the ternary precursor is Ni 0.83 Co 0.12 Mn 0.05 (OH) 2 , the dopants are Zr 2 O 3 , MgO, and NaBO 2 , and the molar proportion of the dopant is 0.52%.
  • the remaining steps are the same as in Example 1, as shown in Table 1.
  • composition of the composite coating agent in this comparative example is CoOOH, Al 2 O 3 and CrO 3 ; the molar ratio of the first coating element (Co), the second coating element (Al) and the third coating element (Cr) is 5:0.7:0.6, the molar ratio of the coating agent is 2.66%, the ternary precursor is Ni 0.83 Co 0.12 Mn 0.05 (OH) 2 , the dopant is MoO 3 , and the molar ratio of the dopant is 0.46 %, and the remaining steps are the same as in Example 1, as shown in Table 1.
  • the composition of the composite coating agent in this comparative example is Mn(OH) 2 and Nb 2 O 5 ; the molar ratio of the first coating element (Mn), the second coating element (Nb) and the third coating element is 3:2:0, the molar ratio of the coating agent is 6.76%, the ternary precursor is Ni 0.83 Co 0.12 Mn 0.05 (OH) 2 , the dopant is Zr 2 O 3 , MgO, NaBO 2 , the dopant The molar ratio was 0.57%, and the remaining steps were the same as in Example 1, as shown in Table 1.
  • the composition of the composite coating agent in this comparative example is NiMnCo(OH) 2 , Nb 2 O 5 , ZrO 2 , in which the first coating element (NiMnCo), the second coating element (Nb) and the third coating element (
  • the molar ratio of Zr) is 1:1:0.6, the molar ratio of the coating agent is 0.19%, the ternary precursor is Ni 0.83 Co 0.12 Mn 0.05 (OH) 2 , and the dopant is Ti 2 O 3 , MgO, Sc 2 O 3 , the molar ratio of the dopant is 0.6%, and the remaining steps are the same as in Example 1, as shown in Table 1.
  • Table 1 is the material process records of Examples 1-10 and Comparative Examples 1-6
  • Preparation of the positive electrode sheet Dissolve the prepared ternary positive electrode material: SP: KS-6: PVDF in NMP with magnetic stirring at a mass ratio of 94.5%: 2%: 1.0%: 2.5%, and stir into a paste. The slurry is then coated on a 15 ⁇ m thick aluminum foil current collector using a coating machine and rolled into shape, dried in an oven at 125°C, and cut into cathode sheets of required size.
  • Preparation of negative electrode plates Dissolve graphite: SP: CMC: SBR in deionized water with magnetic stirring at a mass ratio of 95.5%: 1%: 1.5%: 2.0%, and stir to form a paste slurry, and then use coating
  • the coating machine coats the obtained slurry on a 10 ⁇ m thick copper foil current collector and rolls it into shape. It is dried in an oven at 115°C and cut into negative electrode sheets of the required size.
  • Battery assembly Wind the positive electrode sheet, separator PP, and negative electrode sheet into the required battery core. After baking in an 85°C oven for 10 hours, package the aluminum plastic film and weld the tabs. After the short circuit test, continue to bake for 20 hours for testing. After the moisture content is qualified, processes such as liquid injection, exhaust, sealing, pre-charging, formation, and aging are carried out to obtain the required battery.
  • Comparative Examples 1 to 3 it can be seen that when the cathode material matrix is not coated, the stability of the corresponding battery decreases significantly: the capacity and cycle performance of Comparative Examples 1 to 3 are both lower than those of Examples 1 to 10, and Comparative Example 1 The surface residual alkali and gas production rate of Example 3 are higher than those of Examples 1 to 10.
  • Comparative Examples 4 to 6 it can be seen that when the cathode material matrix is not doped, the corresponding battery The stability of Comparative Examples 4-6 decreased significantly: the capacity and cycle performance of Comparative Examples 4-6 were lower than those of Examples 1-10, and the surface residual alkali and gas production rate of Comparative Examples 4-6 were both higher than those of Examples 1-10.
  • Comparative Examples 7-8 it can be seen that when the proportion of coating elements is not within the range set by this application, the stability of the corresponding battery decreases significantly: the capacity and cycle performance of Comparative Examples 7-8 are both lower than those of the Examples 1 to 10, and the surface residual alkali and gas production rate of Comparative Examples 7 to 8 are higher than those of Examples 1 to 10.
  • Comparative Examples 10-11 when doping and coating are within the scope of the present invention, if the mole fraction of the coating element in the cathode material matrix is excessive, the stability of the corresponding battery will also decrease: Comparative Examples 10-11 The capacity and cycle performance are both lower than those of Examples 1 to 10, and the surface residual alkali and gas production rate of Comparative Examples 10 to 11 are both higher than that of Examples 1 to 10.
  • Comparative Example 12 when the material in the present invention is doped and the doping ratio is within the scope of the present invention, and the coating agent ratio is also within the scope of the present invention, if the coating element contained in the oxide containing lithium coating element If the mole fraction of the total amount of coating elements is lower than the range of the present invention, the stability of the corresponding battery will also decrease: the capacity and cycle performance of Comparative Example 12 are both lower than those of Examples 1 to 10, and the surface residual alkali and The gas production rates are all higher than those in Examples 1 to 10.
  • Comparative Examples 13-14 it can be seen that when doping and coating are within the scope of the present invention, if the molar ratio of each coating element in the lithium-containing coating element oxide is not within the scope of the present invention, the stability of the corresponding battery will be It will also decrease: the capacity and cycle performance of Comparative Examples 13 to 14 are lower than those of the Example 1 to 10, and the surface residual alkali and gas production rate of Comparative Examples 13 to 14 are both higher than those of Examples 1 to 10.
  • the dopant and coating agent in the present invention have the effect of reducing the alkali content on the surface of the material within a certain range and improving the life and capacity of the cathode material.

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Abstract

本发明提供了一种正极材料用复合包覆剂，包括第一包覆剂、第二包覆剂和第三包覆剂；所述第一包覆剂为第一包覆元素的氢氧化物、氧化物、硫化物、硝酸盐或碳酸盐；所述第二包覆剂为第二包覆元素的氢氧化物、氧化物、硫化物、硝酸盐或碳酸盐；所述第三包覆剂为第三包覆元素的氢氧化物、氧化物、硫化物、硝酸盐或碳酸盐。本发明中的复合包覆剂采用不同元素复合在正极材料表面，减少了正极材料中Li的过度析出因而降低了残碱的形成，缓解正极材料表面微裂纹的产生，保护正极材料不与电解液直接接触，包覆后的正极材料残锂及软包电池产气率会降低，提高了材料的安全性及稳定性，生成的包覆元素氧化物的热稳定性及对电解液的保护提升了材料循环稳定性。

Description

一种正极材料用复合包覆剂、一种高镍单晶正极材料和电池
本申请要求于2022年07月22日提交中国专利局、申请号为202210866765.8、发明名称为“一种正极材料用复合包覆剂、一种高镍单晶正极材料和电池”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本发明涉及电池材料技术领域，尤其是涉及一种正极材料用复合包覆剂、一种高镍单晶正极材料和电池。
背景技术
锂离子电池正极材料研究应用非常广泛，现有技术CN109713262A公开了一种钴氧化物包覆正极材料的制备方法。涉及一种钴氧化物包覆正极材料的制备方法，属于电池正极材料技术领域。解决的问题是如何实现降低烧结温度和低包覆量而具有高倍率性能，该方法包括将钴源与高镍正极材料放入容器中，再以≤700rpm的转速条件下进行搅拌混合得到相应的混合物料；在空气或氧气的气氛下，将混合物料在250℃～550℃的条件下进行低温固相烧结处理，得到相应的钴氧化物包覆正极材料；钴氧化物的包覆量为正极材料质量的0.1wt％～1.0wt％。能够有效的实现低钴氧化物包覆的效果，实现材料在高压条件下的倍率和循环性能。但是该文献中单一的钴源包覆，仅仅只是作为隔离层缓解材料和电解液之间的界面反应，减少材料的表面杂质和提高锂离子的传输和减小极化；而退火后包覆的钴不仅在材料表面生成无定形的钴氧化物和少量的钴氧化物，还会生成不良导体四氧化三钴，这不仅阻碍电荷电解液与正极接触阻碍电荷传输从而降低材料的导电性，而且会造成包覆层的不均一及不稳定性，并且并没有解决高镍三元正极内部的Li/Ni混排，缓解内部及外部微裂纹产生的措施。
现有技术CN112194196A，公开了一种超高镍单晶三元正极材用复合包覆剂及其制备方法、应用公开了一种超高镍单晶三元正极材用复合包覆 剂及其制备方法、应用，属于新能源汽车用锂离子动力电池技术领域。一种超高镍单晶三元正极材用复合包覆剂，包括：金属和/或非金属氧化物、铵盐化合物、溶剂中的至少一种，通过球磨、气流粉碎、煅烧、湿法混合、喷雾干燥中的至少一种工艺制备而成。制备的复合包覆剂通过包覆煅烧在单晶材料表面形成一层均匀包覆层，同时可降低表面的残碱水平，提升材料的循环性能及安全性能。但是该文献采用湿法工艺并且增加了湿法包覆液，一方面由于湿法工艺直接将材料表面的残锂洗掉，对材料内部的Li/Ni混排，Li传输通道等并没有改善，并且湿法工艺存在的过洗或不充分洗涤，不均一洗涤对材料表面的正极材料有极大损害，造成材料表面不均匀，循环倍率性能降低等问题。另一方面湿法包覆液的使用容易产生正极材料在充放电过程中包覆剂掉落，包覆剂开裂而使电解液与正极表面直接接触现象，导致正极材料在充电/放电循环中，材料的颗粒更容易出现裂纹然后破裂，这会加速电解质对正极活性物质的腐蚀，从而导致锂离子电池的严重容量下降和较差的循环性能，并且工序繁琐，成本较高，不适合大规模产业化。
因此，提供一种容量高、循环稳定性好的正极材料是非常必要的。
发明内容
有鉴于此，本发明要解决的技术问题在于提供一种高镍单晶正极材料，本发明提供的正极材料容量高、循环稳定性好。
本发明提供了一种正极材料用复合包覆剂，包括第一包覆剂、第二包覆剂和第三包覆剂；所述第一包覆剂为第一包覆元素的氢氧化物、氧化物、硫化物、硝酸盐或碳酸盐；所述第二包覆剂为第二包覆元素的氢氧化物、氧化物、硫化物、硝酸盐或碳酸盐；所述第三包覆剂为第三包覆元素的氢氧化物、氧化物、硫化物、硝酸盐或碳酸盐；
其中，第一包覆元素包括Ni、Mn、Co和B中的一种或几种；第二包覆元素包括Mg、Al、Nb、W和Mo中的一种或几种；第三包覆元素包括Ti、Cr、Zr、Y和Sr中的一种或几种。
优选的，所述第一包覆元素、第二包覆元素和第三包覆元素的摩尔比为1～15∶0.1～18∶0～12。
优选的，所述第一包覆剂为NiMnCo(OH)2、NiMnCoCO3、Co(OH)2、MnCO3、CoCO3、H3BO3、B(NO3)3、CoOOH或Mn(OH)2中的至少一种。
优选的，所述第二包覆剂为MgO、MgCO3、Mg(OH)2、Al2O3、Al(OH)3、MoO3、Mo(OH)3、WO3、Nb(OH)5或Nb2O5中的至少一种；
所述第三包覆剂为TiO、Cr(OH)2、ZrO2、C2O5Zr、Y2O3或Sr(OH)2中的至少一种。
本发明提供了一种包覆层，其特征在于，由上述技术方案任一项所述的包覆剂制备得到。
本发明提供了一种高镍单晶正极材料，其特征在于，包括正极材料基体和设置于所述正极材料基体表面的上述技术方案所述的包覆层。
优选的，所述正极材料基体的结构式为LixNiaMbNcO2，其中0.8≤x≤1.05，0.8≤a≤0.98，b＝1-a-c，0≤c＜0.2；M选自Mn、Co、Al、Mg或Fe中的至少一种；N为掺杂元素，选自Ti、Ta、K、Sb、Na、B、Sc、V、Sn、Y、Zr、Mg、Cr、Nb、W或Mo中的至少一种。
优选的，所述包覆层中包覆元素占正极材料基体的摩尔分数为0.0001～8％。
优选的，所述包覆层由含锂包覆元素氧化物和不含锂包覆元素氧化物组成。
优选的，所述包覆层中，含锂包覆元素氧化物所含包覆元素的摩尔量占包覆元素总量的比例为50％～89％。
优选的，在含锂包覆元素氧化物中，第一包覆元素、第二包覆元素和第三包覆元素的摩尔比为29～100∶0～71∶0～66。
本发明提供了一种高镍单晶正极材料的制备方法，包括如下步骤：
A)将三元前驱体和单水氢氧化锂混合，加入掺杂剂，在保护性气体存在下煅烧，得到煅烧料；
B)将煅烧料破碎、除铁、过筛，得到正极材料基体；
C)将所述正极材料基体与包覆剂混合，在保护性气体存在下再次煅烧，经粉碎、过筛、除铁即得高镍单晶正极材料。
优选的，所述掺杂剂选自TiO、Ti2O3、Sc2O3、MgO、K2CO3、V2O5、 Cr2O3、Sb2O3、Ta2O5、Y2O3、Zr2O3、ZrO2、NaBO2、WO3、MoO3、Nb2O5等其中的至少一种；
步骤A)所述煅烧具体为：以1～10℃.min-1的升温速率，升温至190～420℃，保温3.5～10.5h；再以2～4℃.min-1升温至690～920℃，保温8～11h；再以2～3℃·min-1降温至室温；
步骤C)所述煅烧具体为以3～10℃/min的速率升温至500～810℃，保温9～11h。
本发明提供了一种锂离子电池，包括上述技术方案任一项所述的高镍单晶正极材料或上述技术方案任一项所述的制备方法制备得到的高镍单晶正极材料。
与现有技术相比，本发明提供了一种正极材料用复合包覆剂，包括第一包覆剂、第二包覆剂和第三包覆剂；所述第一包覆剂为第一包覆元素的氢氧化物、氧化物、硫化物、硝酸盐或碳酸盐；所述第二包覆剂为第二包覆元素的氢氧化物、氧化物、硫化物、硝酸盐或碳酸盐；所述第三包覆剂为第三包覆元素的氢氧化物、氧化物、硫化物、硝酸盐或碳酸盐；其中，第一包覆元素包括Ni、Mn、Co和B中的一种或几种；第二包覆元素包括Mg、Al、Nb、W和Mo中的一种或几种；第三包覆元素包括Ti、Cr、Zr、Y和Sr中的一种或几种。本发明中的复合包覆剂采用不同元素复合在正极材料表面，减少了正极材料中Li的过度析出因而降低了残碱的形成，缓解正极材料表面微裂纹的产生，保护正极材料不与电解液直接接触，因此，本发明包覆剂包覆后的正极材料残锂及软包电池产气率会相应降低，提高了本发明中涉及到的正极材料的安全性及稳定性，并且本发明包覆层含有的特殊的含锂包覆元素氧化物具有部分储能作用因而对材料的容量及稳定性等有一定的提升，同时生成的包覆元素氧化物带来的热稳定性及对电解液的保护作用提升了材料循环稳定性，并且对材料没有损害。
具体实施方式
本发明提供了一种正极材料用复合包覆剂、一种高镍单晶正极材料和电池，本领域技术人员可以借鉴本文内容，适当改进工艺参数实现。特别需要指出的是，所有类似的替换和改动对本领域技术人员来说是显而易见 的，它们都属于本发明保护的范围。本发明的方法及应用已经通过较佳实施例进行了描述，相关人员明显能在不脱离本发明内容、精神和范围内对本文的方法和应用进行改动或适当变更与组合，来实现和应用本发明技术。
本发明提供了一种正极材料用复合包覆剂，包括第一包覆剂、第二包覆剂和第三包覆剂；所述第一包覆剂为第一包覆元素的氢氧化物、氧化物、硫化物、硝酸盐或碳酸盐；所述第二包覆剂为第二包覆元素的氢氧化物、氧化物、硫化物、硝酸盐或碳酸盐；所述第三包覆剂为第三包覆元素的氢氧化物、氧化物、硫化物、硝酸盐或碳酸盐；
其中，第一包覆元素包括Ni、Mn、Co和B中的一种或几种；第二包覆元素包括Mg、Al、Nb、W和Mo中的一种或几种；第三包覆元素包括Ti、Cr、Zr、Y和Sr中的一种或几种。
本发明提供的正极材料用复合包覆剂包括第一包覆剂。
按照本发明，所述第一包覆剂为第一包覆元素的氢氧化物、氧化物、硫化物、硝酸盐或碳酸盐；第一包覆元素包括Ni、Mn、Co和B中的一种或几种。
在本发明其中一部分优选实施方式中，所述第一包覆剂为NiMnCo(OH)2、NiMnCoCO3、Co(OH)2、MnCO3、CoCO3、H3BO3、B(NO3)3、CoOOH或Mn(OH)2中的至少一种。
本发明提供的正极材料用复合包覆剂包括第二包覆剂。
本发明所述第二包覆剂为第二包覆元素的氢氧化物、氧化物、硫化物、硝酸盐或碳酸盐；第二包覆元素包括Mg、Al、Nb、W和Mo中的一种或几种。
在本发明其中一部分优选实施方式中，所述第二包覆剂为MgO、MgCO3、Mg(OH)2、Al2O3、Al(OH)3、MoO3、Mo(OH)3、WO3、Nb(OH)5或Nb2O5中的至少一种。
本发明提供的正极材料用复合包覆剂包括第三包覆剂。
本发明所述第三包覆剂为第三包覆元素的氢氧化物、氧化物、硫化物、硝酸盐或碳酸盐；第三包覆元素包括Ti、Cr、Zr、Y和Sr中的一种或几 种。
在本发明其中一部分优选实施方式中，所述第三包覆剂为CrO3、TiO、Cr(OH)2、ZrO2、C2O5Zr、Y2O3或Sr(OH)2中的至少一种。
本发明复合包覆剂含有不同组别的元素种类。这些元素的组合和配比能够作为包覆层减少正极材料中Li的过度析出与残碱的形成，生成具有储能作用的含Li化合物，缓解正极材料表面微裂纹的产生。
本发明提供了一种包覆层，由上述技术方案任一项所述的包覆剂制备得到。
本发明通过第一包覆剂与正极材料在充放电过程中过度析出的Li反应，不仅降低了材料中的Li损失，而且生成了具有储能作用的含锂包覆元素氧化物，防止过度析出的Li与H2O和CO2在一定条件下生成Li2CO3，因此降低了高镍三元正极材料电池的产气。第二包覆剂中的元素一方面能与电解液反应生成固体超强酸，能将正极材料表面的杂质除去并改善正极材料表面SEI膜中的电荷转移以及电解液中的离子运输，抑制其带来的表面阻抗增长；另一方面第二包覆剂的热稳定性较高可抑制氧的生成和增强电解液，最终减少了三元正极材料电化学容量的损失。而第三包覆剂中的元素在包覆后经过处理会进入正极材料的层状结构中与晶格中的氧原子形成化学键提高材料的稳定性，扩大了Li的传输通道，降低了Li/Ni混排，有效地缓解内部应变与结构降解的发生。
本发明提供了一种高镍单晶正极材料，包括正极材料基体和设置于所述正极材料基体表面的上述技术方案所述的包覆层。
本发明所述正极材料基体的结构式为LixNiaMbNcO2，其中0.8≤x≤1.05，0.8≤a≤0.98，b＝1-a-c，0≤c＜0.2；M选自Mn、Co、Al、Mg或Fe中的至少一种；N为掺杂元素，选自Ti、Ta、K、Sb、Na、B、Sc、V、Sn、Y、Zr、Mg、Cr、Nb、W或Mo中的至少一种。
本发明所述高镍单晶正极材料的结构式为LixNiaMbNcO2/K。K为包覆层。
包覆层由上述技术方案任一项所述的包覆剂制备得到；其中一部分包覆剂与锂反应，得到含锂包覆元素氧化物。
因此，本发明的包覆层由含锂包覆元素氧化物和不含锂包覆元素氧化物组成。
第一包覆元素记为K1；第二包覆元素记为K2，第三包覆元素记为K3。
进一步优选的，K1∶K2∶K3＝1～15∶0.1～18∶0～12；K1∶K2∶K3＝1～9∶0.7～4∶0～1.4，K1∶K2∶K3＝5～8∶0.8～1.2∶0～0.2，K1∶K2∶K3＝2～10∶1～10∶0～1，K1∶K2∶K3＝4～8∶0.1～0.8∶0～0.5，K1∶K2∶K3＝10∶1～2∶1，K1∶K2∶K3＝6∶1～2∶0～1，K1∶K2∶K3＝6～10∶1～2∶0～1，K1∶K2∶K3＝6∶1∶0，K1∶K2∶K3＝6～8∶0.5～2∶0～2，K1∶K2∶K3＝6～8∶1～～4.5∶2～～3.5，K1∶K2∶K3＝3∶2∶1，K1∶K2∶K3＝6～8.5∶1∶0.5～1，K1∶K2∶K3＝6∶1～2∶0～0.5，K1∶K2∶K3＝0.2～1.2∶1～2∶0～2，K1∶K2∶K3＝4∶1∶0.5，K1∶K2∶K3＝8∶1.5∶0，K1∶K2∶K3＝6∶0.7∶0.6，K1∶K2∶K3＝7∶1∶0.9，K1∶K2∶K3＝0.4∶1∶1.4；
本发明所述包覆层中包覆元素占正极材料基体的摩尔分数优选为0.0001～8％；更优选为0.1～8％；；最优选为0.19～8％；；
在本发明其中一部分实施例中，所述包覆层中包覆元素占正极材料基体的摩尔分数为0.016～5.6％；进一步的，还可以为0.024～0.92％；进一步的，还可以为0.036～0.78％，进一步的，还可以为0.052～2.7％，进一步的，还可以为0.078～6.2％，进一步的，还可以为4.5～7.6％，进一步的，还可以为3.8～4.8％，进一步的，还可以为3.5～3.9％。
本发明元素K1、K2、K3的存在形式为含锂包覆元素氧化物与少量的不含锂包覆元素氧化物，并且含锂包覆元素氧化物位于正极材料基体的表面，利于储能性能，不含锂包覆元素氧化物位于含锂包覆元素氧化物的外部，利于产气性能。
进一步，本发明所述包覆层由含锂包覆元素氧化物和不含锂包覆元素氧化物组成。
本发明所述含锂包覆元素氧化物是由正极材料中的Li与包覆元素形成的氧化物。
含锂包覆元素氧化物所含包覆元素的摩尔量占包覆元素总量的比例优选为50～89％，更优选为51～83％；不含锂包覆元素氧化物所含包覆元 素的摩尔量占包覆元素总量的比例优选为11～50％。
在含锂包覆元素氧化物中，第一包覆元素记为m1；第二包覆元素记为m2，第三包覆元素记为m3。
其中，在含锂包覆元素氧化物中，m1元素占含锂包覆元素氧化物所含包覆元素的摩尔分数为29～100％，m2元素占含锂包覆元素氧化物所含包覆元素的摩尔分数为0～71％，m3元素占含锂包覆元素氧化物所含包覆元素的摩尔分数为0～66％。
进一步，在含锂包覆元素氧化物中，m1∶m2∶m3＝29～100∶0～71∶0～66；优选的，m1∶m2∶m3＝30～90∶2～30∶0～15。
本发明由于正极材料在与电解液接触过程中会更容易在其近表面区域发生相变，由原始的层状结构转变为尖晶石相和岩盐相，这两种结构的Li离子传导率较低，会降低了Li离子的传输，导致正极材料极化增大；并且由于包覆层需要提供离子及电子的传输通道，因此其特有的不致密性会导致部分电解液与材料表面接触，进而发生材料表面相变，造成正极材料发生容量衰减。
本发明针对上述问题作出解决，在正极材料中掺杂的元素与晶格中的氧原子形成化学键提高材料的稳定性，扩大了Li的传输通道，降低了Li/Ni混排，从而降低正极材料表面NiO岩盐相的形成，有效地缓解内部应变与结构降解的发生；
本发明中掺杂的元素与在正极材料表面形成的含锂包覆元素氧化物及不含锂包覆元素氧化物在稳定材料内部结构的同时，保护了材料表面不受电解液侵蚀，并且能够提供一部分的容量，因此本发明中的掺杂及包覆措施总体上使得单晶材料的循环性能和热稳定性均有较大提升，同时残碱及产气水平比普通单一包覆改性更低，并且能够提升材料整体的容量，得到总体性能良好的高镍单晶三元正极材料。
本发明提供了一种高镍单晶正极材料的制备方法，包括如下步骤：
A)将三元前驱体和单水氢氧化锂混合，加入掺杂剂，在保护性气体存在下煅烧，得到煅烧料；
B)将煅烧料破碎、除铁、过筛，得到正极材料基体；
C)将所述正极材料基体与包覆剂混合，在保护性气体存在下再次煅烧，经粉碎、过筛、除铁即得高镍单晶正极材料。
本发明提供的高镍单晶正极材料的制备方法首先将三元前驱体和单水氢氧化锂混合。
本发明所述三元前驱体优选具体为Ni0.8Co0.12Mn0.08(OH)2，Ni0.8Co0.1Mn0.1(OH)2，Ni0.8Co0.15Al0.05(OH)2，Ni0.82Co0.1Mn0.08(OH)2，Ni0.83Co0.12Mn0.05(OH)2，Ni0.85Co0.05Mn0.1(OH)2，Ni0.85Co0.1Mn0.05(OH)2，Ni0.9Co0.05Mn0.05(OH)2，Ni0.96Co0.02Mn0.02(OH)2，Ni0.98Co0.01Mn0.01(OH)2。
其中，锂与三元前驱体中的金属的摩尔比为0.8～1.05∶1；本发明对于具体的混合方式不进行限定，本领域技术人员熟知的即可。
混合后，加入掺杂剂，在保护性气体存在下煅烧，得到煅烧料；
本发明所述掺杂剂选自所述掺杂剂选自TiO、Ti2O3、Sc2O3、MgO、K2CO3、V2O5、Cr2O3、Sb2O3、Ta2O5、Y2O3、Zr2O3、ZrO2、NaBO2、WO3、MoO3、Nb2O5等其中的至少一种；
本发明所述掺杂剂的添加量优选为0～0.19wt％，0.0001～0.15wt％，0.00015～0.09wt％，0.0002～0.078wt％，0.0032～0.054wt％。
进一步，掺杂元素占正极材料基体的摩尔分数优选为0.28～0.76％；更优选为0.32～0.64％；最优选为0.39～0.64％。
本发明对于所述保护性气氛不进行限定，本领域技术人员熟知的保护性气体即可，包括但不限于氮气、氦气、氩气等。
具体的，所述煅烧具体为：以1～10℃·min-1的升温速率，升温至190～420℃保温3.5～10.5h；再以2～4℃·min-1升温至690～920℃，保温8～11h；再以2～3℃·min-1降温至室温。
将煅烧料破碎、除铁、过筛，得到正极材料基体。
本发明对于所述破碎、除铁、过筛的具体操作不进行限定，本领域技术人员熟知的即可。
将所述正极材料基体与包覆剂混合，在保护性气体存在下再次煅烧。
本发明所述正极材料基体和包覆剂的比例上述已经有了清楚的描述，在此不再赘述。
其中，所述煅烧具体为以3～10℃/min的速率升温至500～810℃，保温9～11h。
而后经粉碎、过筛、除铁即得。本发明对于所述破碎、除铁、过筛的具体操作不进行限定，本领域技术人员熟知的即可。
本发明提供了一种锂离子电池，包括上述技术方案任一项所述的高镍单晶正极材料或上述技术方案任一项所述的制备方法制备得到的高镍单晶正极材料。
本发明采用干法包覆工艺，相比于湿法工艺直接将材料表面的残锂洗掉，对材料内部的Li/Ni混排，Li传输通道等并没有改善，并且湿法工艺存在的特有过洗或不充分洗涤，不均一洗涤对材料表面的正极材料有极大损害，造成材料表面不均匀，循环倍率性能降低等问题。本发明只需对掺杂的正极材料进行直接包覆，从根本上上解决了残碱的生成，对材料没有损害，可获得容量，循环和倍率性能良好的三元材料，从而改善了残碱水平。
本发明中的包覆剂均匀包覆在材料表面，形成密集的小颗粒，隔绝电解液与正极材料接触，提升材料循环寿命。若本发明中复合包覆剂和高镍三元材料的质量比小于0.0001％，则包覆剂不足以完全包覆材料表面，电解液与正极材料接触，导致包覆作用失效，若复合包覆剂和高镍三元材料的质量比大于8％，则会引起包覆层过厚和不均匀，导致锂离子迁移受阻，引起倍率和循环行为下降。
本发明的包覆层在保护正极材料不与电解液接触的同时提供一部分电容，实现了正极材料容量和稳定性的提升，并且改善了正极材料表面残锂与最终软包电池的产气，提高了材料的安全与稳定性能。并且本发明的干法工艺在生产过程中减少大量能耗和设备工序的损耗，因此更有推广量产的优势。
为了进一步说明本发明，以下结合实施例对本发明提供的一种正极材料用复合包覆剂、一种高镍单晶正极材料和电池进行详细描述。
实施例1：
本实施例中复合包覆剂的组成为H3BO3、Mo(OH)3，其中第一包覆 元素(B)、第二包覆元素(Mo)和第三包覆元素的摩尔比为6∶1∶0，均匀混合后记为复合包覆剂1。
S1.将Ni0.85Co0.1Mn0.05(OH)2三元前驱体与电池级单水氢氧化锂以锂元素与金属摩尔比为1.03∶1进行混合，并加入掺杂剂ZrO2，掺杂剂的摩尔占比为0.39％，再在氧气气氛中，以2℃·min-1的升温速率，升温至300℃保温4h；再以2℃·min-1升温至700℃，保温10h；载以3℃·min-1降温至室温，得一次煅烧料；
S2.将一次煅烧料进行粗破碎、精破碎，得粉碎料；
S3.将粉碎料过筛，除铁，即得一次烧结正极材料基体；
S4.将所得的正极材料基体与复合包覆剂1混合均匀，包覆剂的摩尔占比为0.7％，随后置于气氛炉中以5℃/min的速率升温至650℃，保温10h，再经粉碎、过筛，除铁，即得复合包覆剂1包覆的高镍单晶三元正极材料。
实施例2
本实施例中复合包覆剂的组成为CoCO3、MgO，其中第一包覆元素(Co)、第二包覆元素(Mg)和第三包覆元素的摩尔比为1∶1∶0，包覆剂的摩尔占比为1.6％，三元前驱体为Ni0.83Co0.12Mn0.05(OH)2，掺杂剂为TiO，掺杂剂的摩尔占比为0.4％，其余步骤与实施例1相同，具体如表1所示。
实施例3
本实施例中复合包覆剂的组成为CoOOH、Al2O3、CrO3，其中第一包覆元素(Co)、第二包覆元素(Al)和第三包覆元素(Cr)的摩尔比为6∶0.7∶0.6，包覆剂的摩尔占比为3.71％，三元前驱体为Ni0.82Co0.1Mn0.08(OH)2，掺杂剂为Y2O3，掺杂剂的摩尔占比为0.52％，其余步骤与实施例1相同，具体如表1所示。
实施例4
本实施例中复合包覆剂的组成为Co(OH)2、MoO3；其中第一包覆元素(Co)、第二包覆元素(Mo)和第三包覆元素的摩尔比为5∶0.7∶0，包覆剂的摩尔占比为2.66％，三元前驱体为Ni0.85Co0.05Mn0.1(OH)2，掺杂剂为MgO、Ta2O5，掺杂剂的摩尔占比为0.46％，其余步骤与实施例1相同， 具体如表1所示。
实施例5
本实施例中复合包覆剂的组成为Mn(OH)2、Nb2O5，其中第一包覆元素(Mn)、第二包覆元素(Nb)和第三包覆元素的摩尔比为6∶1∶0，包覆剂的摩尔占比为4.91％，三元前驱体为Ni0.8Co0.1Mn0.1(OH)2，掺杂剂为MoO3、NaBO2，掺杂剂的摩尔占比为0.5％，其余步骤与实施例1相同，具体如表1所示。
实施例6
本实施例中复合包覆剂的组成为NiMnCo(OH)2∶Nb2O5∶ZrO2其中第一包覆元素(Ni、Mn、Co)、第二包覆元素(Nb)和第三包覆元素(Zr)的摩尔比为3∶2∶1，包覆剂的摩尔占比为6.76％，三元前驱体为Ni0.8Co0.1Mn0.1(OH)2，掺杂剂为ZrO2、Cr2O3，掺杂剂的摩尔占比为0.57％，其余步骤与实施例1相同，具体如表1所示。
实施例7
本实施例中复合包覆剂的组成为B(NO3)3、WO3；其中第一包覆元素(B)、第二包覆元素(W)和第三包覆元素的摩尔比为6∶1∶0，包覆剂的摩尔占比为0.19％，三元前驱体为Ni0.9Co0.05Mn0.05(OH)2，掺杂剂为MoO3、NaBO2、TiO，掺杂剂的摩尔占比为0.6％，其余步骤与实施例1相同，具体如表1所示。
实施例8
本实施例中复合包覆剂的组成为Mn(OH)2∶Al2O3∶Sr(OH)2，其中第一包覆元素(Mn)、第二包覆元素(Al)和第三包覆元素(Sr)的摩尔比为7∶1∶0.9，包覆剂的摩尔占比为0.86％，三元前驱体为Ni0.96Co0.02Mn0.02(OH)2，掺杂剂为MoO3、Zr2O3、NaBO2，掺杂剂的摩尔占比为0.64％，其余步骤与实施例1相同，具体如表1所示。
实施例9
本实施例中复合包覆剂的组成为MnCO3∶Al2O3∶0其中第一包覆元素(Mn)、第二包覆元素(Al)和第三包覆元素的摩尔比为5∶1.5∶0，包覆剂的摩尔占比为8.0％，三元前驱体为Ni0.9Co0.05Mn0.05(OH)2，掺杂剂为 Nb2O5，掺杂剂的摩尔占比为0.62％，其余步骤与实施例1相同，具体如表1所示。
实施例10
本实施例中复合包覆剂的组成为NiMnCoCO3∶WO3∶TiO其中第一包覆元素(NiMnCo)、第二包覆元素(W)和第三包覆元素(Ti)的摩尔比为0.4∶1∶1.4，包覆剂的摩尔占比为0.8％，三元前驱体为Ni0.8Co0.15Al0.05(OH)2，掺杂剂为Ti2O3、Sc2O3、MgO，掺杂剂的摩尔占比为0.56％，其余步骤与实施例1相同，具体如表1所示。
对比例1：
S1.将Ni0.83Co0.12Mn0.05(OH)2三元前驱体与电池级单水氢氧化锂以锂元素与金属摩尔比为1∶1.03进行混合，并加入掺杂剂TiO，掺杂剂的摩尔占比为0.4％，再在氧气气氛中，以2℃·min-1的升温速率，升温至300℃保温4h；再以2℃·min-1升温至700℃，保温10h；载以3℃·min-1降温至室温，得一次煅烧料；
S2.将一次煅烧料进行粗破碎、精破碎，得粉碎料；
S3.将粉碎料过筛，除铁，即得高镍单晶三元正极材料。
对比例2
本对比例中不含包覆剂，三元前驱体为Ni0.83Co0.12Mn0.05(OH)2，掺杂剂为Sc2O3、MgO，掺杂剂的摩尔占比为0.57％，其余步骤与对比例1相同，具体如表1所示。
对比例3
本对比例中不含包覆剂，三元前驱体为Ni0.83Co0.12Mn0.05(OH)2，掺杂剂为MoO3、Zr2O3、NaBO2，掺杂剂的摩尔占比为0.64％，其余步骤与对比例1相同，具体如表1所示。
对比例4
本对比例中包覆剂为NiCoMnCO3，包覆剂的摩尔占比为0.2％，三元前驱体为Ni0.83Co0.12Mn0.05(OH)2，不含掺杂剂，其余步骤与实施例1相同，具体如表1所示。
对比例5
本对比例中包覆剂组成为MnCO3、MgO，其中第一包覆元素(Mn)、第二包覆元素(Mg)和第三包覆元素的摩尔比为1∶1∶0，包覆剂的摩尔占比为0.4％，三元前驱体为Ni0.83Co0.12Mn0.05(OH)2，不含掺杂剂，其余步骤与实施例1相同，具体如表1所示。
对比例6
本对比例中包覆剂组成为NiCoMnCO3、MgO、Sr(OH)2，其中第一包覆元素(NiCoMn)、第二包覆元素(Mg)和第三包覆元素(Sr)的摩尔比为1∶1∶1，包覆剂的摩尔占比为0.6％，三元前驱体为Ni0.83Co0.12Mn0.05(OH)2，不含掺杂剂，其余步骤与实施例1相同，具体如表1所示。
对比例7
本对比例中复合包覆剂的组成为Co(OH)2、WO3、TiO；其中第一包覆元素(Co)、第二包覆元素(W)和第三包覆元素(Ti)的摩尔比为0.4∶20∶1.4，包覆剂的摩尔占比为6.71％，三元前驱体为Ni0.83Co0.12Mn0.05(OH)2，掺杂剂为Ti2O3、Sc2O3、MgO，掺杂剂的摩尔占比为0.56％，其余步骤与实施例1相同，具体如表1所示。
对比例8
本对比例中复合包覆剂的组成为MnCO3、Al2O3、Y2O3，其中第一包覆元素(Mn)、第二包覆元素(Al)和第三包覆元素(Y)的摩尔比为17∶1∶0.9，包覆剂的摩尔占比为4.8％，三元前驱体为Ni0.83Co0.12Mn0.05(OH)2，掺杂剂为Sc2O3、MgO，掺杂剂的摩尔占比为0.56％，其余步骤与实施例1相同，具体如表1所示。
对比例9
本对比例中复合包覆剂的组成为Zn(OH)2、CaO、Ba(OH)2第一包覆元素(Zn)、第二包覆元素(Ca)和第三包覆元素(Ba)的摩尔比为6∶1∶0，包覆剂的摩尔占比为1.6％，三元前驱体为Ni0.83Co0.12Mn0.05(OH)2，掺杂剂为MoO3，掺杂剂的摩尔占比为0.39％，其余步骤与实施例1相同，具体如表1所示。
对比例10
本对比例中复合包覆剂的组成为H3BO3、Mo(OH)3；第一包覆元素(B)、第二包覆元素(Mo)和第三包覆元素的摩尔比为1∶1∶0，包覆剂的摩尔占比为9.9％，三元前驱体为Ni0.83Co0.12Mn0.05(OH)2，掺杂剂为Ti2O3、Sc2O3，掺杂剂的摩尔占比为0.4％，其余步骤与实施例1相同，具体如表1所示。
对比例11
本对比例中复合包覆剂的组成为CoCO3、MgO；第一包覆元素(Co)、第二包覆元素(Mg)和第三包覆元素的摩尔比为6∶0.7∶0，包覆剂的摩尔占比为8.8％，三元前驱体为Ni0.83Co0.12Mn0.05(OH)2，掺杂剂为Zr2O3、MgO、NaBO2，掺杂剂的摩尔占比为0.52％，其余步骤与实施例1相同，具体如表1所示。
对比例12
本对比例中复合包覆剂的组成为CoOOH、Al2O3、CrO3；第一包覆元素(Co)、第二包覆元素(Al)和第三包覆元素(Cr)的摩尔比为5∶0.7∶0.6，包覆剂的摩尔占比为2.66％，三元前驱体为Ni0.83Co0.12Mn0.05(OH)2，掺杂剂为MoO3，掺杂剂的摩尔占比为0.46％，其余步骤与实施例1相同，具体如表1所示。
对比例13
本对比例中复合包覆剂的组成为Mn(OH)2、Nb2O5；其中第一包覆元素(Mn)、第二包覆元素(Nb)和第三包覆元素的摩尔比为3∶2∶0，包覆剂的摩尔占比为6.76％，三元前驱体为Ni0.83Co0.12Mn0.05(OH)2，掺杂剂为Zr2O3、MgO、NaBO2，掺杂剂的摩尔占比为0.57％，其余步骤与实施例1相同，具体如表1所示。
对比例14
本对比例中复合包覆剂的组成为NiMnCo(OH)2、Nb2O5、ZrO2，其中第一包覆元素(NiMnCo)、第二包覆元素(Nb)和第三包覆元素(Zr)的摩尔比为1∶1∶0.6，包覆剂的摩尔占比为0.19％，三元前驱体为Ni0.83Co0.12Mn0.05(OH)2，掺杂剂为Ti2O3、MgO、Sc2O3，掺杂剂的摩尔占比为0.6％，其余步骤与实施例1相同，具体如表1所示。
表1为实施例1-10与对比例1-6的材料工艺记录


(1)电化学性能测试
正极极片的制备：将制备的三元正极材料∶SP∶KS-6∶PVDF按照质量比94.5％∶2％∶1.0％∶2.5％的比例，磁力搅拌溶解在NMP中，并搅拌成糊状浆料，然后用涂覆机将所得浆料涂覆在15μm厚的铝箔集流体上并辊压成型，于125℃烤箱中烘干，裁切成所需尺寸的正极片。
负极极片的制备：将石墨∶SP∶CMC∶SBR按照质量比95.5％∶1％∶1.5％∶2.0％的比例，磁力搅拌溶解在去离子水中，并搅拌成糊状浆料，然后用涂覆机将所得浆料涂覆在10μm厚的铜箔集流体上并辊压成型，于115℃烤箱中烘干，裁切成所需尺寸的负极片。
电池的组装：将正极极片、隔膜PP、负极极片卷绕成所需电芯，在85℃烘箱内烘烤10h后，包装铝塑膜、极耳焊接，短路测试后继续烘烤20h测试水分合格后进行注液、排气、封口、预充、化成、老化等工序，得到所需电池。
表2实施例1～10与对比例1～6的材料容量及循环数据测试结果

注：95％SOC指电池循环一定次数后的容量为初始容量的95％。
(2)残碱测试
对实施例1～10及对比例1～6样品的残碱含量进行测试，具体利用电位滴定法进行测试，测试结果参见表3：
表3实施例1～10与对比例1～6的材料残碱及产气数据测试结果
由表可知，本发明采用的干法包覆复合包覆剂所得的材料容量和循环稳定性提升，并且表面残碱低。
参考对比例1～3的数据可知，当正极材料基体无包覆时，相应电池的稳定性显著下降：对比例1～3的容量和循环性能均低于实施例1～10，且对比例1～3的表面残碱和产气率均高于实施例1～10。
参考对比例4～6的数据可知，当正极材料基体无掺杂时，相应电池 的稳定性显著下降：对比例4～6的容量和循环性能均低于实施例1～10，且对比例4～6的表面残碱和产气率均高于实施例1～10。
参考对比例7～8的数据可知，当包覆元素的比例不在本申请所设定的范围内时，相应电池的稳定性显著下降：对比例7～8的容量和循环性能均低于实施例1～10，且对比例7～8的表面残碱和产气率均高于实施例1～10。
参考对比例9的数据可知，当掺杂本发明中的材料且掺杂比例在本发明范围内，包覆剂不在本发明范围内时，相应电池的稳定性下降：对比例9的容量和循环性能均低于实施例1～10，且对比例9的表面残碱和产气率均高于实施例1～10。
参考对比例10～11的数据可知，掺杂及包覆在本发明范围内时，若包覆元素占正极材料基体的摩尔分数过量，相应电池的稳定性也会下降：对比例10～11的容量和循环性能均低于实施例1～10，且对比例10～11的表面残碱和产气率均高于实施例1～10。
参考对比例12的数据可知，掺杂本发明中的材料且掺杂比例在本发明范围内，包覆剂比例也在本发明范围内时，若含锂包覆元素氧化物所含包覆元素占包覆元素总量的摩尔分数低于本发明范围，相应电池的稳定性也会下降：对比例12的容量和循环性能均低于实施例1～10，且对比例12的表面残碱和产气率均高于实施例1～10。
参考对比例13～14的数据可知，掺杂及包覆都在本发明范围内时，若含锂包覆元素氧化物中各包覆元素的摩尔比不在本发明范围内，相应电池的稳定性也会下降：对比例13～14的容量和循环性能均低于实施例 1～10，且对比例13～14的表面残碱和产气率均高于实施例1～10。
综合以上实施例与对比例结果，在本发明掺杂与包覆材料范围内，若相应比例也符合本发明，则正极材料的残碱及产气率大大降低，容量略有提升，并且循环寿命也有提升。因此，本发明中的掺杂剂与包覆剂在一定范围内具有降低材料表面碱量，并且提高正极材料寿命与容量的作用。
以上所述仅是本发明的优选实施方式，应当指出，对于本技术领域的普通技术人员来说，在不脱离本发明原理的前提下，还可以做出若干改进和润饰，这些改进和润饰也应视为本发明的保护范围。

Claims (13)

  1. 一种正极材料用复合包覆剂，其特征在于，包括第一包覆剂、第二包覆剂和第三包覆剂；所述第一包覆剂为第一包覆元素的氢氧化物、氧化物、硫化物、硝酸盐或碳酸盐；所述第二包覆剂为第二包覆元素的氢氧化物、氧化物、硫化物、硝酸盐或碳酸盐；所述第三包覆剂为第三包覆元素的氢氧化物、氧化物、硫化物、硝酸盐或碳酸盐；
    其中，第一包覆元素包括Ni、Mn、Co和B中的一种或几种；第二包覆元素包括Mg、Al、Nb、W和Mo中的一种或几种；第三包覆元素包括Ti、Cr、Zr、Y和Sr中的一种或几种。
  2. 根据权利要求1所述的包覆剂，其特征在于，所述第一包覆元素、第二包覆元素和第三包覆元素的摩尔比为1～15∶0.1～18∶0～12。
  3. 根据权利要求1所述的包覆剂，其特征在于，所述第一包覆剂为NiMnCo(OH)2、NiMnCoCO3、Co(OH)2、MnCO3、CoCO3、H3BO3、B(NO3)3、CoOOH或Mn(OH)2中的至少一种；
    所述第二包覆剂为MgO、MgCO3、Mg(OH)2、Al2O3、Al(OH)3、MoO3、Mo(OH)3、WO3、Nb(OH)5或Nb2O5中的至少一种；
    所述第三包覆剂为TiO、Cr(OH)2、ZrO2、C2O5Zr、Y2O3或Sr(OH)2中的至少一种。
  4. 一种包覆层，其特征在于，由权利要求1～3任一项所述的包覆剂制备得到。
  5. 一种高镍单晶正极材料，其特征在于，包括正极材料基体和设置于所述正极材料基体表面的权利要求4所述的包覆层。
  6. 根据权利要求5所述的高镍单晶正极材料，其特征在于，所述正极材料基体的结构式为LixNiaMbNcO2，其中0.8≤x≤1.05，0.8≤a≤0.98，b＝1-a-c，0≤c＜0.2；M选自Mn、Co、Al、Mg或Fe中的至少一种；N为掺杂元素，选自Ti、Ta、K、Sb、Na、B、Sc、V、Sn、Y、Zr、Mg、Cr、Nb、W或Mo中的至少一种。
  7. 根据权利要求5所述的高镍单晶正极材料，其特征在于，所述包 覆层中包覆元素占正极材料基体的摩尔分数为0.0001～8％。
  8. 根据权利要求5所述的高镍单晶正极材料，其特征在于，所述包覆层由含锂包覆元素氧化物和不含锂包覆元素氧化物组成。
  9. 根据权利要求8所述的高镍单晶正极材料，其特征在于，所述包覆层中，含锂包覆元素氧化物所含包覆元素的摩尔量占包覆元素总量的比例为50％～89％。
  10. 根据权利要求8所述的高镍单晶正极材料，其特征在于，在含锂包覆元素氧化物中，第一包覆元素、第二包覆元素和第三包覆元素的摩尔比为29～100∶0～71∶0～66。
  11. 一种高镍单晶正极材料的制备方法，其特征在于，包括如下步骤：
    A)将三元前驱体和单水氢氧化锂混合，加入掺杂剂，在保护性气体存在下煅烧，得到煅烧料；
    B)将煅烧料破碎、除铁、过筛，得到正极材料基体；
    C)将所述正极材料基体与包覆剂混合，在保护性气体存在下再次煅烧，经粉碎、过筛、除铁即得高镍单晶正极材料。
  12. 根据权利要求11所述的高镍单晶正极材料的制备方法，其特征在于，所述掺杂剂选自TiO、Ti2O3、Sc2O3、MgO、K2CO3、V2O5、Cr2O3、Sb2O3、Ta2O5、Y2O3、ZrO2、Zr2O3、NaBO2、WO3、MoO3、Nb2O5等其中的至少一种；
    步骤A)所述煅烧具体为：以1～10℃·min-1的升温速率，升温至190～420℃，保温3.5～10.5h；再以2～4℃·min-1升温至690～920℃，保温8～11h；再以2～3℃·min-1降温至室温；
    步骤C)所述煅烧具体为以3～10℃/min的速率升温至500～810℃，保温9～11h。
  13. 一种锂离子电池，其特征在于，包括权利要求5～10任一项所述的高镍单晶正极材料或权利要求11～12任一项所述的制备方法制备得到的高镍单晶正极材料。
PCT/CN2023/077793 2022-07-22 2023-02-23 一种正极材料用复合包覆剂、一种高镍单晶正极材料和电池 WO2024016662A1 (zh)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN118326513A (zh) * 2024-06-11 2024-07-12 贵州振华新材料股份有限公司 一种单晶正极材料及其制备方法

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115036493A (zh) * 2022-07-22 2022-09-09 宁波容百新能源科技股份有限公司 一种正极材料用复合包覆剂、一种高镍单晶正极材料和电池
CN115472838A (zh) * 2022-09-27 2022-12-13 深圳市贝特瑞纳米科技有限公司 一种正极材料及其制备方法和锂离子电池
CN116314704B (zh) * 2023-03-29 2024-04-02 安徽得壹能源科技有限公司 一种包覆改性钠离子层状正极材料及其制备方法
CN116454269B (zh) * 2023-06-13 2024-04-16 江门市科恒实业股份有限公司 一种钴酸锂正极材料及其制备方法和电池

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109273710A (zh) * 2018-08-22 2019-01-25 中伟新材料有限公司 一种掺杂包覆型单晶三元正极材料制备方法
CN111463411A (zh) * 2019-01-18 2020-07-28 天津国安盟固利新材料科技股份有限公司 一种单晶形貌的高镍三元正极材料及其制备方法
CN112310389A (zh) * 2020-08-27 2021-02-02 浙江美都海创锂电科技有限公司 一种超高镍单晶正极材料、制备方法及应用
CN113540433A (zh) * 2021-06-28 2021-10-22 合肥国轩高科动力能源有限公司 一种正极材料及制备方法、锂离子电池正极和锂离子电池
CN114094067A (zh) * 2021-11-09 2022-02-25 远景动力技术(江苏)有限公司 三元正极材料、其制备方法及其用途
CN114249357A (zh) * 2021-12-27 2022-03-29 宁波容百新能源科技股份有限公司 一种表面改性高镍三元正极材料及其干法制备工艺
CN115036493A (zh) * 2022-07-22 2022-09-09 宁波容百新能源科技股份有限公司 一种正极材料用复合包覆剂、一种高镍单晶正极材料和电池

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN100533822C (zh) * 2006-09-29 2009-08-26 比亚迪股份有限公司 正极活性物质及其制备方法以及正极和电池
CN105428631A (zh) * 2016-01-20 2016-03-23 宁德新能源科技有限公司 一种锂电池正极材料，其制备方法及含有该材料的锂离子电池
CN111244397A (zh) * 2018-11-28 2020-06-05 天津国安盟固利新材料科技股份有限公司 一种高镍三元正极材料及其制备方法
CN113764628A (zh) * 2020-06-01 2021-12-07 蜂巢能源科技有限公司 一种双层包覆四元正极材料及其制备方法
CN113488634B (zh) * 2021-07-29 2022-09-13 浙江帕瓦新能源股份有限公司 双层包覆改性高镍无钴单晶三元正极材料及其制备方法
CN113839040B (zh) * 2021-08-31 2023-03-07 蜂巢能源科技有限公司 高镍三元正极材料及其制备方法、锂离子电池
CN114284470B (zh) * 2021-11-29 2023-07-14 蜂巢能源科技有限公司 正极材料、其制备方法、包括其的正极和锂离子电池

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109273710A (zh) * 2018-08-22 2019-01-25 中伟新材料有限公司 一种掺杂包覆型单晶三元正极材料制备方法
CN111463411A (zh) * 2019-01-18 2020-07-28 天津国安盟固利新材料科技股份有限公司 一种单晶形貌的高镍三元正极材料及其制备方法
CN112310389A (zh) * 2020-08-27 2021-02-02 浙江美都海创锂电科技有限公司 一种超高镍单晶正极材料、制备方法及应用
CN113540433A (zh) * 2021-06-28 2021-10-22 合肥国轩高科动力能源有限公司 一种正极材料及制备方法、锂离子电池正极和锂离子电池
CN114094067A (zh) * 2021-11-09 2022-02-25 远景动力技术(江苏)有限公司 三元正极材料、其制备方法及其用途
CN114249357A (zh) * 2021-12-27 2022-03-29 宁波容百新能源科技股份有限公司 一种表面改性高镍三元正极材料及其干法制备工艺
CN115036493A (zh) * 2022-07-22 2022-09-09 宁波容百新能源科技股份有限公司 一种正极材料用复合包覆剂、一种高镍单晶正极材料和电池

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN118326513A (zh) * 2024-06-11 2024-07-12 贵州振华新材料股份有限公司 一种单晶正极材料及其制备方法

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