Monocrystal cobalt-free high-nickel positive electrode material as well as preparation method and application thereof

Abstract

The invention relates to a single-crystal cobalt-free high-nickel positive electrode material and a preparation method and application thereof.The single-crystal cobalt-free high-nickel positive electrode material comprises doping elements, the doping elements comprise the combination of metal elements and non-metal elements, the metal elements comprise any one of Nb, W, Zr, Al, Zn or Ti or the combination of at least two of Nb, W, Zr, Al, Zn or Ti, the non-metallic element comprises any one or a combination of at least two of B, P or N. Through the cobalt-free design, the material cost is reduced, the use of scarce metal resources is reduced, the stability and electrochemical performance of the single-crystal cobalt-free high-nickel positive electrode material can be greatly improved through co-doping of metal and non-metal elements, the single-crystal cobalt-free high-nickel positive electrode material can be prepared in one step by adopting a spray pyrolysis method, and the preparation method is simple and convenient. The obtained single-crystal cobalt-free high-nickel positive electrode material is uniform in morphology and good in dispersity, and the high-efficiency and low-cost single-crystal cobalt-free high-nickel positive electrode material can be produced and developed on a large scale.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of single-crystal cobalt-free high-nickel positive electrode material preparation, and particularly relates to a single-crystal cobalt-free high-nickel positive electrode material and a preparation method and application thereof. BACKGROUND

[0002] The positive electrode material of a lithium ion battery has become the most potential battery system due to its high specific capacity and high energy density. The electrochemical performance of high-nickel positive electrode material is significantly improved, making it a key research direction to realize a high-energy-density battery with a capacity of 500 Wh / kg. The structure of single-crystal high-nickel positive electrode material is not easy to crack during charging and discharging compared with traditional polycrystal materials, reducing the electrolyte side reaction caused by particle cracking, reducing the risk of thermal runaway, and having a longer cycle life, usually more than 2000 cycles. However, the preparation process of single-crystal high-nickel positive electrode material is complex (high-temperature sintering, long-time annealing, etc.), resulting in a production cost much higher than that of polycrystal materials, which limits its large-scale application. In addition, to reduce the cost and environmental hazards, reducing the use of cobalt is an important strategy. However, for high-nickel positive electrode materials, reducing or completely removing cobalt will also reduce the stability and electrochemical performance of the materials. Therefore, for single-crystal cobalt-free high-nickel positive electrode materials, how to effectively improve the stability and electrochemical performance while achieving simple and efficient preparation of single crystals is still a technical problem. Existing research shows that element doping can effectively improve the stability of cobalt-free positive electrodes, but the selection of element types and how to achieve more uniform element doping still need further research.

[0003] CN114843458A discloses a high-nickel single-crystal cobalt-free positive electrode material and a preparation method thereof. The structure of the high-nickel single-crystal cobalt-free positive electrode material has a general formula of LiNi a Mn b A c B d O2@C, wherein a+b+c=1, a≥0.6, 0<c≤0.1, 0<d≤0.1; A is one or more of Ta, Mg, Al, Ga, Nb, Ti, and B is one or more of F, Cl, S. Although it uses co-doping of cations and anions to inhibit cation mixing, enhance the bond energy between transition metals and anions, and reduce side reactions such as oxygen release, in the preparation method, a multi-step molten salt method is used, which needs to prepare a precursor first, then mix with lithium salt and molten salt by two-step ball milling, and then calcine to obtain the product. The preparation process is relatively complex, and in the process of ball milling, the external force of ball milling can cause agglomeration and segregation of the doped elements. In addition, the auxiliary material consumption is large and the cost is relatively high.

[0004] CN118957753A discloses a lithium battery single crystal positive electrode material, a preparation method and application thereof, comprising two-stage spray pyrolysis treatment on a raw material liquid containing a lithium source, a nickel source, a cobalt source, a manganese source and a metal element source to obtain lithium nickel cobalt manganese oxide single crystal particles. It discloses the preparation of single crystal positive electrode material by spray pyrolysis method, but the uniformity of the particle size of the obtained single crystal positive electrode material needs to be improved, and long-time spray pyrolysis treatment is also not conducive to the dispersion of the particle size, which also has a certain influence on the performance in the later use process.

[0005] Therefore, how to provide a single crystal cobalt-free high-nickel positive electrode material and a preparation method, which can not only greatly improve the stability and electrochemical performance of the single crystal cobalt-free high-nickel positive electrode material, but also can efficiently and low-costly prepare the single crystal material, is a technical problem to be solved at present. SUMMARY

[0006] To solve the above technical problems, the present application provides a single crystal cobalt-free high-nickel positive electrode material and a preparation method and application thereof. The present application realizes the reduction of material cost and the reduction of the use of scarce metal resources by cobalt-free design, and greatly improves the stability and electrochemical performance of the single crystal cobalt-free high-nickel positive electrode material by co-doping of metal and non-metal elements. The metal element is doped in the crystal lattice gap, which can increase the interlayer distance of the positive electrode layered structure and accelerate the diffusion rate of lithium ions, thereby improving the conductivity and cycle performance. The non-metal element can inhibit the migration of transition metal (TM) and the escape of internal lattice oxygen of the positive electrode material at high voltage by using its characteristics of strengthening metal-non-metal bonds, thereby greatly improving the cycle stability of the single crystal cobalt-free high-nickel positive electrode material.

[0007] To achieve this purpose, the present application adopts the following technical solutions:

[0008] In a first aspect, the present application provides a single crystal cobalt-free high-nickel positive electrode material, which comprises a doping element, the doping element comprises a combination of a metal element and a non-metal element, the metal element comprises any one or a combination of at least two of Nb, W, Zr, Al, Zn or Ti, and the non-metal element comprises any one or a combination of at least two of B, P or N.

[0009] The present application can greatly improve the stability and electrochemical performance of the single crystal cobalt-free high-nickel positive electrode material by co-doping of metal and non-metal elements, wherein the metal element comprises any one or a combination of at least two of Nb, W, Zr, Al, Zn or Ti, because they are all with Ni 2+The radius is close, so it can be doped in the lattice gap, increase the interlayer distance of the positive electrode layered structure and accelerate the diffusion rate of lithium ions, thereby improving the conductivity and cycle performance, the non-metallic element includes any one or combination of at least two of B, P or N, by using the characteristics of strengthening metal-nonmetal bond, the transition metal (TM) migration and the escape of the internal lattice oxygen of the positive electrode material at high voltage can be inhibited, at the same time, the increase of the interlayer distance also makes it easier for the non-metallic element to be replaced, which is convenient for strengthening the metal-nonmetal bond, and further greatly improves the cycle stability of the single-crystal cobalt-free high-nickel positive electrode material.

[0010] In addition, the present application reduces the preparation cost through the cobalt-free design, reduces the harm to the environment in the battery recycling process, and the co-doping of metal and non-metallic elements also improves the problem of reduced stability of the positive electrode material caused by the absence of cobalt, thereby obtaining a single-crystal cobalt-free high-nickel positive electrode material with overall performance.

[0011] As a preferred technical solution of the present application, the metal element includes any one or combination of at least two of Nb, W or Zr.

[0012] Preferably, the chemical general formula of the single-crystal cobalt-free high-nickel positive electrode material is Li m Ni x Mn y R z T n O 2-n , wherein 0 m Ni x Mn y R z T n O 2-n , x+y=1, 0.8 m Ni x Mn y R z T n O 2-n , 0 m Ni x Mn y R z T n O 2-n , R is the metal element, and T is the non-metallic element.

[0013] In a second aspect, the present application also provides a preparation method of the single-crystal cobalt-free high-nickel positive electrode material according to the first aspect, and the preparation method comprises the following steps:

[0014] Spray pyrolysis of the precursor solution to obtain a single-crystal cobalt-free high-nickel positive electrode material;

[0015] The precursor solution comprises a lithium source, a nickel source, a manganese source, a metal source, a non-metallic source and a solvent.

[0016] The metal element in the metal source includes any one or a combination of at least two of Nb, W, Zr, Al, Zn or Ti;

[0017] The non-metal element in the non-metal source includes any one or a combination of at least two of B, P or N.

[0018] The spray pyrolysis method adopted in the application can realize efficient and low-cost uniform co-doping of metal elements and non-metal elements, and the preparation of single-crystal cobalt-free high-nickel positive electrode materials can be realized in one step. The obtained single-crystal cobalt-free high-nickel positive electrode material has uniform morphology and good dispersity, and compared with the preparation by the coprecipitation method, the preparation period is greatly shortened and the preparation cost is reduced.

[0019] As a preferred technical solution of the application, the metal element in the metal source includes any one or a combination of at least two of Nb, W or Zr.

[0020] Preferably, the method of spray pyrolysis includes: atomizing the precursor solution by a spray gun with a carrier gas, and then heating and decomposing in a furnace.

[0021] As a preferred technical solution of the application, the temperature of the furnace is 600℃ to 950℃, for example, 600℃, 620℃, 650℃, 680℃, 700℃, 720℃, 750℃, 780℃, 800℃, 820℃, 850℃, 880℃, 900℃, 920℃ or 950℃, etc.

[0022] In the application, the temperature of the furnace is controlled to be 600℃ to 950℃, so as to realize complete decomposition of the precursor solution and obtain single-crystal cobalt-free high-nickel positive electrode material with uniform element distribution. If the temperature of the furnace is too low, the solvent (deionized water) in the precursor solution may not be completely evaporated, and the precursor solution may not be fully decomposed. If the temperature of the furnace is too high, the crystallinity of the single-crystal cobalt-free high-nickel positive electrode material may be too high, and even metal oxide phase impurities may be formed, thereby reducing the content of part of the metal elements in the single-crystal cobalt-free high-nickel positive electrode material and making the metal elements not uniformly distributed.

[0023] Preferably, the pressure of the spray gun is 0.2MPa to 0.5MPa, for example, 0.2MPa, 0.3MPa, 0.4MPa or 0.5MPa, etc.

[0024] Preferably, the time of heating and decomposition is 3s to 8s, for example, 3s, 4s, 5s, 6s, 7s or 8s, etc.

[0025] Preferably, the molar amount of the metal element in the metal source is 0.05mol% to 1mol% of the total molar amount of Ni element in the nickel source and Mn element in the manganese source, for example, 0.05mol%, 0.08mol%, 0.1mol%, 0.2mol%, 0.3mol%, 0.4mol%, 0.5mol%, 0.6mol%, 0.7mol%, 0.8mol%, 0.9mol% or 1mol%, etc.

[0026] In the present application, the molar amount of the metal element in the metal source is controlled to be 0.05mol% to 1mol% of the total molar amount of Ni element in the nickel source and Mn element in the manganese source, which can reduce lithium-nickel mixing and irreversible phase transition. If the doping amount of the metal element is too small, lithium-nickel mixing will be intensified; if the doping amount of the metal element is too large, lattice stress will be increased, causing lattice distortion and cracks in the crystal.

[0027] Preferably, the flow rate of the carrier gas is 2L / h to 4L / h, for example, 2L / h, 2.5L / h, 3L / h, 3.5L / h or 4L / h, etc.

[0028] It should be noted that the type of carrier gas is not specifically required or specially limited in the present application, and the type of carrier gas commonly used in the art can be selected and adjusted as needed by those skilled in the art, for example, compressed air.

[0029] Preferably, the molar amount of the non-metal element in the non-metal source is 0.05mol% to 1mol% of the total molar amount of Ni element in the nickel source and Mn element in the manganese source, for example, 0.05mol%, 0.08mol%, 0.1mol%, 0.2mol%, 0.3mol%, 0.4mol%, 0.5mol%, 0.6mol%, 0.7mol%, 0.8mol%, 0.9mol% or 1mol%, etc.

[0030] In the present application, the molar amount of the non-metal element in the non-metal source is controlled to be 0.05mol% to 1mol% of the total molar amount of Ni element in the nickel source and Mn element in the manganese source, which can replace O2- in the lattice to form a metal-non-metal bond with higher stability, significantly inhibit the formation of oxygen vacancies and transition metal (TM) migration at high voltage, and reduce structural collapse. If the doping amount of the non-metal element is too small, the amount of oxygen released will increase, the phase transition will be intensified, the number of oxygen vacancies on the material surface will increase, and the instability of the material will increase; if the doping amount of the non-metal element is too large, charge imbalance will occur, lattice stress will increase, causing lattice distortion and capacity loss of the positive electrode material.

[0031] As a preferred technical scheme of the present application, the molar ratio of Li, Ni and Mn in the lithium source, the nickel source and the manganese source is Li:Ni:Mn=a:b:(1-b), wherein 0

[0032] As a preferred technical scheme of the present application, the concentration of the precursor solution is 100g / L-160g / L, for example, 100g / L, 110g / L, 120g / L, 130g / L, 140g / L, 150g / L or 160g / L, etc.

[0033] Preferably, the metal source includes any one or a combination of at least two of ammonium oxalate oxy niobate, tungsten nitrate, zirconium nitrate, aluminum nitrate, zinc nitrate or titanium nitrate, preferably any one or a combination of at least two of ammonium oxalate oxy niobate, tungsten nitrate or zirconium nitrate.

[0034] Preferably, the non-metal source includes any one or a combination of at least two of boric acid, ammonia or sodium phosphate.

[0035] Preferably, the lithium source includes any one or a combination of at least two of lithium nitrate, lithium carbonate, lithium sulfate or lithium chloride.

[0036] Preferably, the nickel source includes any one or a combination of at least two of nickel nitrate, nickel carbonate or nickel sulfate.

[0037] Preferably, the manganese source includes any one or a combination of at least two of manganese nitrate, manganese carbonate or manganese sulfate.

[0038] Preferably, the solvent includes deionized water.

[0039] As a preferred technical scheme of the present application, the preparation method comprises the following steps:

[0040] The precursor solution with a concentration of 100g / L-160g / L is atomized by a spray gun pressure of 0.2MPa-0.5MPa using a carrier gas with a flow rate of 2L / h-4L / h, and then heated and decomposed in a furnace at 600℃-950℃ for 3s-8s to obtain a single-crystal cobalt-free high-nickel positive electrode material.

[0041] The precursor solution comprises a lithium source, a nickel source, a manganese source, a metal source, a non-metal source and a solvent; the metal element in the metal source comprises any one or a combination of at least two of Nb, W, Zr, Al, Zn or Ti; the non-metal element in the non-metal source comprises any one or a combination of at least two of B, P or N;

[0042] The molar amount of the metal element in the metal source is 0.05mol% to 1mol% of the total molar amount of the Ni element in the nickel source and the Mn element in the manganese source; the molar amount of the non-metal element in the non-metal source is 0.05mol% to 1mol% of the total molar amount of the Ni element in the nickel source and the Mn element in the manganese source; the molar ratio of the Li element in the lithium source, the Ni element in the nickel source and the Mn element in the manganese source is Li:Ni:Mn=a:b:(1-b), wherein 0

[0043] In a third aspect, the present application further provides an application of the single-crystal cobalt-free high-nickel positive electrode material. The single-crystal cobalt-free high-nickel positive electrode material prepared by the preparation method according to the second aspect is applied to a lithium ion battery.

[0044] Compared with the prior art, the present application has at least the following beneficial effects:

[0045] 1) The present application realizes the reduction of material cost and the reduction of the use of scarce metal resources through the cobalt-free design, and the stability and electrochemical performance of the single-crystal cobalt-free high-nickel positive electrode material can be greatly improved through the co-doping of metal and non-metal elements. The metal element is doped in the crystal lattice gap, which can increase the interlayer distance of the positive electrode layered structure and accelerate the diffusion rate of lithium ions, thereby improving the conductivity and cycle performance. The non-metal element can inhibit the migration of transition metals (TM) and the escape of lattice oxygen inside the positive electrode material at high voltage by using its characteristics of strengthening metal-non-metal bonds, thereby greatly improving the cycle stability of the single-crystal cobalt-free high-nickel positive electrode material.

[0046] 2) The present application adopts a spray pyrolysis preparation method, which can realize efficient and low-cost uniform co-doping of metal elements and non-metal elements. The single-crystal cobalt-free high-nickel positive electrode material can be prepared in one step. The obtained single-crystal cobalt-free high-nickel positive electrode material has uniform morphology and good dispersity, and can realize large-scale production. DETAILED DESCRIPTION

[0047] In order to facilitate the understanding of the present application, the present application is illustrated as follows. It should be understood by those skilled in the art that the examples are only used to help understand the present application and should not be regarded as a specific limitation on the present application.

[0048] The raw materials and reagents used in the following examples are commercially available or can be prepared by known methods unless otherwise stated.

[0049] Example 1

[0050] The present example provides a single-crystal cobalt-free high-nickel positive electrode material, the chemical formula of which is Li 0.3 Ni 0.9 Mn 0.1 Nb 0.003 B 0.003 O 1.997 ;

[0051] The preparation method comprises the following steps:

[0052] A mixed aqueous solution of lithium nitrate, nickel nitrate, manganese nitrate, ammonium oxalatooxy niobate, and boric acid is prepared as a precursor solution according to the molar ratio of Li:Ni:Mn:Nb:B in the chemical formula 0.3:0.9:0.1:0.003:0.003, with a concentration of 150 g / L. The hearth is heated to a temperature of 650°C, the pressure of the spray gun is set to 0.3 MPa, and the precursor solution is atomized by the spray gun using compressed air with a flow rate of 3 L / h, and then heated and decomposed in the 650°C hearth for 5 s, to obtain a single-crystal cobalt-free high-nickel positive electrode material with the chemical formula Li 0.3 Ni 0.9 Mn 0.1 Nb 0.003 B 0.00 3O 1.997 .

[0053] Example 2

[0054] The present example provides a single-crystal cobalt-free high-nickel positive electrode material, the chemical formula of which is Li 0.3 Ni 0.85 Mn 0.15 Nb 0.002 B 0.004 O 1.996 ;

[0055] The preparation method comprises the following steps:

[0056] A mixed aqueous solution of lithium nitrate, nickel nitrate, manganese nitrate, ammonium oxalatooxy niobate, and boric acid is prepared as a precursor solution according to the molar ratio of Li:Ni:Mn:Nb:B in the chemical formula 0.3:0.85:0.15:0.002:0.004, with a concentration of 150 g / L. The hearth is heated to a temperature of 750°C, the pressure of the spray gun is set to 0.3 MPa, and the precursor solution is atomized by the spray gun using compressed air with a flow rate of 3 L / h, and then heated and decomposed in the 750°C hearth for 5 s, to obtain a single-crystal cobalt-free high-nickel positive electrode material with the chemical formula Li 0.3Ni 0.85 Mn 0.15 Nb 0.00 2B 0.004 O 1.996 A single crystal cobalt-free high-nickel positive electrode material.

[0057] Example 3

[0058] The present example provides a single crystal cobalt-free high-nickel positive electrode material, the chemical formula of which is Li 0.3 Ni 0.95 Mn 0.05 Nb 0.001 B 0.006 O 1.994 ;

[0059] The preparation method comprises the following steps:

[0060] A mixed aqueous solution of lithium nitrate, nickel nitrate, manganese nitrate, ammonium oxalato oxonitrate, and boric acid is prepared as a precursor solution according to the molar ratio of Li:Ni:Mn:Nb:B in the chemical formula 0.3:0.95:0.05:0.001:0.006, the concentration is 150 g / L, the temperature of the furnace is heated to 850 ℃, the pressure of the spray gun is set to 0.3 MPa, the precursor solution is atomized by the spray gun using compressed air with a flow rate of 3 L / h, and then heated and decomposed in the furnace at 850 ℃ for 5 s to obtain a single crystal cobalt-free high-nickel positive electrode material with the chemical formula Li 0.3 Ni 0.95 Mn 0.05 Nb 0.00 1B 0.006 O 1.994 .

[0061] Example 4

[0062] The present example provides a single crystal cobalt-free high-nickel positive electrode material, the chemical formula of which is Li 0.3 Ni 0.85 Mn 0.15 Nb 0.003 B 0.003 O 1.997 ;

[0063] The difference between the preparation method and Example 1 is that a mixed aqueous solution of lithium nitrate, nickel nitrate, manganese nitrate, ammonium oxalato oxonitrate, and boric acid is prepared as a precursor solution according to the molar ratio of Li:Ni:Mn:Nb:B in the chemical formula 0.3:0.85:0.15:0.003:0.003 to obtain a single crystal cobalt-free high-nickel positive electrode material with the chemical formula Li 0.3 Ni 0.85 Mn 0.15 Nb 0.003 B 0.003 O1.997 Li0.3Ni0.95Mn0.05Nb0.003B0.003O2, the rest of the preparation method and parameters remain unchanged with example 1.

[0064] Example 5

[0065] This example provides a single crystal cobalt-free high nickel positive electrode material, the chemical formula of the single crystal cobalt-free high nickel positive electrode material is Li 0.3 Ni 0.95 Mn 0.05 Nb 0.003 B 0.003 O 1.997 ;

[0066] The difference between the preparation method and example 1 is that the mixed aqueous solution of lithium nitrate, nickel nitrate, manganese nitrate, ammonium oxalate niobate and boric acid is prepared as a precursor solution according to the molar ratio of Li:Ni:Mn:Nb:B in the chemical formula 0.3:0.95:0.05:0.003:0.003, to obtain a single crystal cobalt-free high nickel positive electrode material with the chemical formula Li 0.3 Ni 0.95 Mn 0.05 Nb 0.003 B 0.003 O 1.997 The rest of the preparation method and parameters remain unchanged with example 1.

[0067] Example 6

[0068] This example provides a single crystal cobalt-free high nickel positive electrode material, the chemical formula of the single crystal cobalt-free high nickel positive electrode material is Li 0.3 Ni 0.9 Mn 0.1 Nb 0.003 B 0.003 O 1.997 ;

[0069] The difference between the preparation method and example 1 is that the temperature of the hearth is 750℃, and the rest of the preparation method and parameters remain unchanged with example 1.

[0070] Example 7

[0071] This example provides a single crystal cobalt-free high nickel positive electrode material, the chemical formula of the single crystal cobalt-free high nickel positive electrode material is Li 0.3 Ni 0.9 Mn 0.1 Nb 0.003 B 0.003 O 1.997 ;

[0072] The difference between the preparation method and example 1 is that the temperature of the hearth is 850℃, and the rest of the preparation method and parameters remain unchanged with example 1.

[0073] Example 8

[0074] This example provides a single-crystal cobalt-free high-nickel positive electrode material, the chemical formula of which is Li 0.3 Ni 0.9 Mn 0.1 Nb 0.001 B 0.003 O 1.997 ;

[0075] The difference between the preparation method and Example 1 is that a mixed aqueous solution of lithium nitrate, nickel nitrate, manganese nitrate, ammonium oxalato oxonitrate, and boric acid is prepared as a precursor solution according to the molar ratio of Li:Ni:Mn:Nb:B in the chemical formula 0.3:0.9:0.1:0.001:0.003, to obtain a single-crystal cobalt-free high-nickel positive electrode material with the chemical formula Li 0.3 Ni 0.9 Mn 0.1 Nb 0.001 B 0.003 O 1.997 The rest of the preparation method and parameters remain the same as Example 1.

[0076] Example 9

[0077] This example provides a single-crystal cobalt-free high-nickel positive electrode material, the chemical formula of which is Li 0.3 Ni 0.9 Mn 0.1 Nb 0.002 B 0.003 O 1.997 ;

[0078] The difference between the preparation method and Example 1 is that a mixed aqueous solution of lithium nitrate, nickel nitrate, manganese nitrate, ammonium oxalato oxonitrate, and boric acid is prepared as a precursor solution according to the molar ratio of Li:Ni:Mn:Nb:B in the chemical formula 0.3:0.9:0.1:0.002:0.003, to obtain a single-crystal cobalt-free high-nickel positive electrode material with the chemical formula Li 0.3 Ni 0.9 Mn 0.1 Nb 0.002 B 0.003 O 1.997 The rest of the preparation method and parameters remain the same as Example 1.

[0079] Example 10

[0080] This example provides a single-crystal cobalt-free high-nickel positive electrode material, the chemical formula of which is Li 0.5 Ni 0.9 Mn 0.1 Zr 0.01P 0.01 O 1.99 ;

[0081] The preparation method is different from that of Example 1 in that a mixed aqueous solution of lithium nitrate, nickel nitrate, manganese nitrate, zirconium nitrate and sodium phosphate is prepared as a precursor solution according to a molar ratio of Li:Ni:Mn:Zr:P in the chemical formula of 0.5:0.9:0.1:0.01:0.01, to obtain a single-crystal cobalt-free high-nickel positive electrode material with a chemical formula of Li 0.5 Ni 0.9 Mn 0.1 Zr 0.01 P 0.01 O 1.99 , and the rest of the preparation method and parameters remain the same as those of Example 1.

[0082] Example 11

[0083] This example provides a single-crystal cobalt-free high-nickel positive electrode material, which has a chemical formula of Li 0.3 Ni 0.9 Mn 0.1 Nb 0.003 B 0.003 O 1.997 ;

[0084] The preparation method is different from that of Example 1 in that the temperature of the furnace is 950°C, and the rest of the preparation method and parameters remain the same as those of Example 1.

[0085] Example 12

[0086] This example provides a single-crystal cobalt-free high-nickel positive electrode material, which has a chemical formula of Li 0.3 Ni 0.9 Mn 0.1 Nb 0.003 B 0.003 O 1.997 ;

[0087] The preparation method is different from that of Example 1 in that the temperature of the furnace is 550°C, and the rest of the preparation method and parameters remain the same as those of Example 1.

[0088] Example 13

[0089] This example provides a single-crystal cobalt-free high-nickel positive electrode material, which has a chemical formula of Li 0.3 Ni 0.9 Mn 0.1 Nb 0.003 B 0.003 O 1.997 ;

[0090] The preparation method is different from that of Example 1 in that the temperature of the furnace is 1000℃, and the rest of the preparation method and parameters remain the same as those of Example 1.

[0091] Example 14

[0092] This example provides a single-crystal cobalt-free high-nickel positive electrode material, the chemical formula of which is Li 0.3 Ni 0.9 Mn 0.1 Nb 0.015 B 0.003 O 1.997 ;

[0093] The preparation method is different from that of Example 1 in that a mixed aqueous solution of lithium nitrate, nickel nitrate, manganese nitrate, ammonium oxalatooxy niobate and boric acid is prepared as a precursor solution according to the molar ratio of Li:Ni:Mn:Nb:B in the chemical formula 0.3:0.9:0.1:0.015:0.003, to obtain a single-crystal cobalt-free high-nickel positive electrode material with the chemical formula Li 0.3 Ni 0.9 Mn 0.1 Nb 0.015 B 0.003 O 1.997 , and the rest of the preparation method and parameters remain the same as those of Example 1.

[0094] Example 15

[0095] This example provides a single-crystal cobalt-free high-nickel positive electrode material, the chemical formula of which is Li 0.3 Ni 0.9 Mn 0.1 Nb 0.003 B 0.015 O 1.985 ;

[0096] The preparation method is different from that of Example 1 in that a mixed aqueous solution of lithium nitrate, nickel nitrate, manganese nitrate, ammonium oxalatooxy niobate and boric acid is prepared as a precursor solution according to the molar ratio of Li:Ni:Mn:Nb:B in the chemical formula 0.3:0.9:0.1:0.003:0.015, to obtain a single-crystal cobalt-free high-nickel positive electrode material with the chemical formula Li 0.3 Ni 0.9 Mn 0.1 Nb 0.003 B 0.015 O 1.985 , and the rest of the preparation method and parameters remain the same as those of Example 1.

[0097] Comparative Example 1

[0098] The comparative example 1 provides a single crystal cobalt-free high nickel positive electrode material, the chemical formula of the single crystal cobalt-free high nickel positive electrode material is Li 0.3 Ni 0.9 Mn 0.1 Nb 0.003 O2.

[0099] The difference between the preparation method and example 1 is that the mixed aqueous solution of lithium nitrate, nickel nitrate, manganese nitrate and ammonium oxalate niobate is prepared as a precursor solution according to the molar ratio of Li:Ni:Mn:Nb in the chemical formula 0.3:0.9:0.1:0.003, and a single crystal cobalt-free high nickel positive electrode material with the chemical formula of Li 0.3 Ni 0.9 Mn 0.1 Nb 0.003 O2 is obtained, and the rest of the preparation method and parameters remain the same as example 1.

[0100] Comparative example 2

[0101] The comparative example 1 provides a single crystal cobalt-free high nickel positive electrode material, the chemical formula of the single crystal cobalt-free high nickel positive electrode material is Li 0.3 Ni 0.9 Mn 0.1 B 0.003 O 1.997 .

[0102] The difference between the preparation method and example 1 is that the mixed aqueous solution of lithium nitrate, nickel nitrate, manganese nitrate and boric acid is prepared as a precursor solution according to the molar ratio of Li:Ni:Mn:B in the chemical formula 0.3:0.9:0.1:0.003, and a single crystal cobalt-free high nickel positive electrode material with the chemical formula of Li 0.3 Ni 0.9 Mn 0.1 B 0.003 O 1.997 is obtained, and the rest of the preparation method and parameters remain the same as example 1.

[0103] Comparative example 3

[0104] The comparative example 1 provides a single crystal cobalt-free high nickel positive electrode material, the chemical formula of the single crystal cobalt-free high nickel positive electrode material is Li 0.3 Ni 0.9 Mn 0.1 Nb 0.006 O2.

[0105] The difference between the preparation method and example 1 is that the mixed aqueous solution of lithium nitrate, nickel nitrate, manganese nitrate and ammonium oxalate niobate is prepared as a precursor solution according to the molar ratio of Li:Ni:Mn:Nb in the chemical formula 0.3:0.9:0.1:0.006, and a single crystal cobalt-free high nickel positive electrode material with the chemical formula of Li 0.3 Ni0.9 Mn 0.1 Nb 0.006 O2of a single crystal cobalt-free high-nickel positive electrode material, the remaining preparation method and parameters remain unchanged with Example 1.

[0106] Comparative Example 4

[0107] This comparative example provides a single crystal cobalt-free high-nickel positive electrode material, the chemical formula of which is Li 0.3 Ni 0.9 Mn 0.1 B 0.006 O 1.994 ;

[0108] The preparation method is different from Example 1 in that a mixed aqueous solution of lithium nitrate, nickel nitrate, manganese nitrate and boric acid is prepared as a precursor solution according to the molar ratio of Li:Ni:Mn:B in the chemical formula 0.3:0.9:0.1:0.006, to obtain a single crystal cobalt-free high-nickel positive electrode material with a chemical formula of Li 0.3 Ni 0.9 Mn 0.1 B 0.006 O 1.994 The remaining preparation method and parameters remain unchanged with Example 1.

[0109] Application Examples 1-15 and Comparative Application Examples 1-4

[0110] The single crystal cobalt-free high-nickel positive electrode material provided in Examples 1-15 and Comparative Examples 1-4 is dissolved in a certain amount of NMP with a mass ratio of 8:1:1 with conductive agent LiPF6 and binder PVDF, and mixed to a moderate viscosity slurry. The slurry is coated on an aluminum foil, vacuum dried and rolled to make a positive electrode sheet. A lithium metal sheet is used as the negative electrode, a separator, and an electrolyte of 1.0 mol / L LiPF6 solution (solvent is a volume ratio of 1:1:1 of EC, DMC and EMC) to assemble a coin cell battery, which corresponds to Application Examples 1-15 and Comparative Application Examples 1-4, respectively.

[0111] The coin cells assembled in Application Examples 1-15 and Comparative Application Examples 1-4 are left to stand for 24 hours, and then subjected to electrochemical performance tests, with the following test conditions: voltage range 2.5V-4.3V, 0.5C discharge specific capacity, capacity retention rate after 200 cycles at room temperature under 0.5C / 1C conditions. The specific test results are shown in Table 1.

[0112] Table 1

[0113]

[0114]

[0115] From the test results, it can be seen that:

[0116] (1) As can be seen from Application Examples 1 to 11, by adopting a cobalt-free design, the present application realizes the reduction of material cost and the reduction of the use of scarce metal resources, and by co-doping of metal and non-metal elements, the stability and electrochemical performance of the single-crystal cobalt-free high-nickel positive electrode material can be greatly improved, wherein the metal element is doped in the crystal lattice gap, which can increase the interlayer distance of the positive electrode layered structure and accelerate the diffusion rate of lithium ions, thereby improving the conductivity and cycle performance, and the non-metal element can inhibit the transition metal (TM) migration and the escape of lattice oxygen inside the positive electrode material at high voltage by using its characteristics of strengthening the metal-non-metal bond, thereby greatly improving the cycle stability of the single-crystal cobalt-free high-nickel positive electrode material. Specifically, the discharge specific capacity of the button cell is 165.3 mAh / g to 171.1 mAh / g at 0.5C, and the capacity retention rate is 90.5% to 93.5% at 0.5C / 1C for 200 cycles.

[0117] (2) As can be seen from Application Examples 1 and 12-13, by further regulating the temperature of the furnace to 600℃ to 950℃, the present application realizes the complete decomposition of the precursor solution, and obtains a single-crystal cobalt-free high-nickel positive electrode material with uniform element distribution, without the generation of other metal oxide impurities. The discharge specific capacity and capacity retention rate of the button cell assembled from the obtained single-crystal cobalt-free high-nickel positive electrode material are both more optimal.

[0118] (3) As can be seen from Application Examples 1 and 14-15, by further regulating the molar amount of the metal elements in the metal source to be 0.05mol% to 1mol% of the total molar amount of Ni elements in the nickel source and Mn elements in the manganese source, the present application can reduce lithium-nickel mixing and irreversible phase change, and improve the stability and electrochemical performance of the single-crystal cobalt-free high-nickel positive electrode material.

[0119] By further regulating the molar amount of the non-metal elements in the non-metal source to be 0.05mol% to 1mol% of the total molar amount of Ni elements in the nickel source and Mn elements in the manganese source, the non-metal elements can replace O 2 - form stronger metal-non-metal bonds, significantly inhibit the formation of oxygen vacancies and transition metal (TM) migration at high voltage, reduce structure collapse, and thus also have obvious improvement effect on the stability and electrochemical performance of the single-crystal cobalt-free high-nickel positive electrode material.

[0120] (3) Through the application example 1 and the comparative application examples 1-2, it can be seen that, by co-doping of metal and non-metal elements, the stability and electrochemical performance of the single-crystal cobalt-free high-nickel positive electrode material can be greatly improved, wherein the metal element is doped in the lattice gap, which can increase the interlayer distance of the positive electrode layered structure and accelerate the diffusion rate of lithium ions, thereby improving the conductivity and cycle performance, and the non-metal element can inhibit the transition metal (TM) migration and the escape of the internal lattice oxygen of the positive electrode material at high voltage by virtue of its ability to strengthen the metal-non-metal bond, thereby greatly improving the cycle stability of the single-crystal cobalt-free high-nickel positive electrode material. When the B element (non-metal element) is omitted, the content of the Nb element remains unchanged, or the Nb element (metal element) is omitted, the content of the B element remains unchanged, that is, the addition of one element is missing, the stability and electrochemical performance of the obtained single-crystal cobalt-free high-nickel positive electrode material are greatly reduced.

[0121] (4) Through the application example 1 and the comparative application examples 3-4, it can be seen that, when the B element (non-metal element) is omitted, the content of the Nb element is the total content of the B element and the Nb element in the embodiment 1, or the Nb element (metal element) is omitted, the content of the B element is the total content of the B element and the Nb element in the embodiment 1, the stability and electrochemical performance of the obtained single-crystal cobalt-free high-nickel positive electrode material are still greatly reduced. It can be seen that, only by the synergistic effect of the metal element and the non-metal element, by doping the metal element between the layers, expanding the interlayer distance, and accelerating the diffusion rate of lithium ions, and by strengthening the metal (transition metal)-non-metal bond by the non-metal element to improve the cycle stability of the material, the obtained single-crystal cobalt-free high-nickel positive electrode material can have better stability and electrochemical performance.

[0122] In summary, by the cobalt-free design, the material cost is reduced and the use of scarce metal resources is reduced, and by co-doping of metal and non-metal elements, the stability and electrochemical performance of the single-crystal cobalt-free high-nickel positive electrode material can be greatly improved, wherein the metal element is doped in the lattice gap, which can increase the interlayer distance of the positive electrode layered structure and accelerate the diffusion rate of lithium ions, thereby improving the conductivity and cycle performance, and the non-metal element can inhibit the transition metal (TM) migration and the escape of the internal lattice oxygen of the positive electrode material at high voltage by virtue of its ability to strengthen the metal-non-metal bond, thereby greatly improving the cycle stability of the single-crystal cobalt-free high-nickel positive electrode material. In addition, by using the spray pyrolysis preparation method, efficient and low-cost uniform co-doping of the metal element and the non-metal element can be achieved, and the single-crystal cobalt-free high-nickel positive electrode material can be prepared in one step, and the obtained single-crystal cobalt-free high-nickel positive electrode material has uniform morphology and good dispersity, and can be mass-produced.

[0123] The applicant states that the above description is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and it should be understood by those skilled in the art that any changes or replacements within the technical scope disclosed by the present application can be easily thought out by those skilled in the art, and all of them fall within the protection scope and disclosure scope of the present application.

Claims

1. A single-crystalline cobalt-free high-nickel positive electrode material, characterized in that, The single-crystal cobalt-free high-nickel positive electrode material comprises a doping element, the doping element comprises a combination of a metal element and a non-metal element, the metal element comprises any one or a combination of at least two of Nb, W, Zr, Al, Zn or Ti, and the non-metal element comprises any one or a combination of at least two of B, P or N.

2. The single-crystalline cobalt-free high-nickel cathode material of claim 1, wherein, The metal element comprises any one or a combination of at least two of Nb, W or Zr. Preferably, the single-crystal cobalt-free high-nickel positive electrode material has a chemical general formula of Li m Ni x Mn y R z T n O 2-n wherein 0 3. A method of producing a single-crystal cobalt-free high-nickel positive electrode material according to claim 1 or 2, characterized by, The preparation method comprises the following steps: The precursor solution is subjected to spray pyrolysis to obtain the single-crystal cobalt-free high-nickel positive electrode material. The precursor solution comprises a lithium source, a nickel source, a manganese source, a metal source, a non-metal source and a solvent. The metal element in the metal source comprises any one or a combination of at least two of Nb, W, Zr, Al, Zn or Ti. The non-metal element in the non-metal source comprises any one or a combination of at least two of B, P or N.

4. The production method according to claim 3, characterized by, The metal element in the metal source comprises any one or a combination of at least two of Nb, W or Zr. Preferably, the method of spray pyrolysis comprises atomizing the precursor solution by a spray gun with a carrier gas and then decomposing the precursor solution in a furnace.

5. The preparation method according to claim 4, characterized in that, The temperature of the furnace is 600-950 DEG C. Preferably, the pressure of the spray gun is 0.2-0.5 MPa. Preferably, the time of the heating and decomposing is 3-8 s.

6. The method of any one of claims 3-5, wherein, The molar amount of the metal element in the metal source is 0.05-1 mol% of the total molar amount of the Ni element in the nickel source and the Mn element in the manganese source.

7. The method of any one of claims 3-6, wherein, The molar amount of the non-metal element in the non-metal source is 0.05-1 mol% of the total molar amount of the Ni element in the nickel source and the Mn element in the manganese source.

8. The method of any one of claims 3-7, wherein, The molar ratio of the Li element in the lithium source, the Ni element in the nickel source and the Mn element in the manganese source is Li:Ni:Mn=a:b:(1-b), wherein 0 9. The method of any one of claims 3-8, wherein, The concentration of the precursor solution is 100-160 g / L. Preferably, the metal source comprises any one or a combination of at least two of ammonium oxalate oxy niobate, tungsten nitrate, zirconium nitrate, aluminum nitrate, zinc nitrate or titanium nitrate, preferably any one or a combination of at least two of ammonium oxalate oxy niobate, tungsten nitrate or zirconium nitrate. Preferably, the non-metal source comprises any one or a combination of at least two of boric acid, ammonia water or sodium phosphate. Preferably, the solvent comprises deionized water.

10. Use of a single-crystalline cobalt-free high-nickel cathode material, characterized in that The single-crystal cobalt-free high-nickel positive electrode material of claim 1 or 2, or the single-crystal cobalt-free high-nickel positive electrode material prepared by the preparation method of any one of claims 3-9, is applied in a lithium ion battery.

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