A high-nickel ternary cathode material with high thermal safety, preparation method thereof, and application thereof

Abstract

The present invention provides a high-nickel ternary cathode material with high thermal safety. The high-nickel ternary cathode material provided by the present invention identifies important factors affecting the thermal safety of the ternary cathode material by measuring its thermal conductivity K, D104 value in XRD, and porosity α. By controlling these parameters and satisfying the relationship shown in Formula I, corresponding materials are prepared for verification. Furthermore, the high-nickel ternary cathode material is improved by coating it with a coating material having low thermal conductivity. Testing the thermal conductivity of the coated material shows that as the coating amount of the coating material increases, the overall thermal conductivity of the ternary cathode material decreases while simultaneously having better thermal safety.

Description

Technical Field

[0001] The present invention belongs to the technical field of lithium-ion batteries, and in particular relates to a high-nickel ternary positive electrode material with high thermal safety, a preparation method thereof, and applications thereof. Background Art

[0002] With the popularity of new energy electric vehicles, cathode materials, one of the main raw materials of batteries, have also attracted everyone's attention, among which the most prominent are ternary cathode materials. The main application of these materials is power energy batteries. However, in recent years, there have been frequent spontaneous combustion phenomena of new energy vehicles, and the safety of new energy vehicles has been pushed to the forefront. Faced with such a situation, how to ensure the thermal safety of batteries has become an urgent problem to be solved by various manufacturers and research institutions. At present, there have been some new breakthroughs at the battery level, but there are few results in the field of cathode ternary materials. The existing patent CN108550802A uses a small amount of Y 3+ ions, La 3+ Ions replace part of Ni 3+ Use Y 3+ / La 3+ The electrochemical inertness of the ions reduces volume changes during charge and discharge, increasing structural stability and improving thermal safety. Patent CN112811403A improves the material's crystal structure stability through Mg / Ti co-doping, while simultaneously combining it with Li3PO4 coating to achieve a layered distribution of doping and coating. The Li3PO4 coating enhances surface stability, helps reduce electrochemical impedance and electrolyte side reactions, and thus improves the thermal stability of the high-nickel ternary cathode material.

[0003] Existing processes typically enhance the structural stability of materials by doping them with electrochemically inert substances. They also coat them with stabilizing substances to isolate the ternary positive electrode material from HF, suppressing material decomposition and heat release from metal dissolution. However, doping with these electrochemically inert substances significantly impacts the material's inherent electronic conductivity and reaction activity, negatively impacting its electrochemical performance. Furthermore, this multi-element doping and multi-step coating process increases cost and complexity. Summary of the Invention

[0004] In view of this, the technical problem to be solved by the present invention is to provide a high-nickel ternary positive electrode material with high thermal safety, a preparation method thereof, and an application thereof. The high-nickel ternary positive electrode material provided by the present invention has an overall lower thermal conductivity and better thermal safety, and has good electrical properties.

[0005] The present invention provides a high-nickel ternary cathode material with high thermal safety. The chemical formula of the high-nickel ternary cathode material is:

[0006] LiNia Co b Mn c M d Q e O2,

[0007] Among them, 0.8<a<0.95, b<0.2, c<0.2, d<0.1, a+b+c+d+e=1,

[0008] M is a doping element, selected from one or more of Sr, Ti, Al, Zr, Y, Ba, Mg, and Mo,

[0009] Q is a coating element, selected from one or both of Sr and Ti,

[0010] The high nickel ternary cathode material satisfies the relationship shown in Formula I:

[0011] γ=α*D104 / K Formula I

[0012] In formula I, 0.73≤γ≤14.00, γ is the thermal safety factor of the high nickel ternary positive electrode material, α is the cross-sectional porosity of the high nickel ternary positive electrode material, D104 is a parameter in the XRD test of the high nickel ternary positive electrode material, and K is the thermal conductivity of the high nickel ternary positive electrode material.

[0013] Preferably, 45≤D104≤70.

[0014] Preferably, 1%≤α≤5%.

[0015] Preferably, 0.1 W / (m·K)≤K≤0.6 W / (m·K).

[0016] Preferably, it comprises a core and a cladding layer, and the thermal conductivity of the cladding layer is ≤0.2 W / (m·K).

[0017] The present invention also provides a method for preparing the above-mentioned high-nickel ternary positive electrode material, comprising the following steps:

[0018] A) Ni a Co b Mn c (OH)2, a lithium source and a compound containing an M element are mixed and sintered in an oxygen atmosphere to obtain a sintered product;

[0019] B) washing and drying the sintered product, mixing it with a compound containing the Q element, and sintering it in an oxygen atmosphere to obtain a high-nickel ternary positive electrode material.

[0020] Preferably, the lithium source is selected from LiOH;

[0021] The compound containing the M element is selected from one or more of Al(OH)3, Al2O3, SrO, TiO2, ZrO2, Zr(OH)4, Y2O3, BaCO3, MgO, and MoO3;

[0022] The compound containing the Q element is selected from TiO2, SrO, and SrTiO3.

[0023] Preferably, in step A), the sintering temperature is 740° C. to 820° C., and the sintering time is 10 to 15 hours.

[0024] Preferably, in step B), the sintering temperature is 350-500° C. and the sintering time is 8-12 hours.

[0025] The present invention also provides a lithium-ion battery comprising the above-mentioned high-nickel ternary positive electrode material.

[0026] Compared with the prior art, the present invention provides a high-nickel ternary cathode material with high thermal safety. The chemical formula of the high-nickel ternary cathode material is: LiNi a Co b Mn c M d Q e O2, wherein, 0.8<a<0.95, b<0.2, c<0.2, d<0.1, a+b+c+d+e=1, M is a doping element selected from one or more of Sr, Ti, Al, Zr, Y, Ba, Mg, and Mo, Q is a coating element selected from one or two of Sr and Ti, and the high-nickel ternary positive electrode material satisfies the relationship shown in Formula I: γ=α*D104 / K Formula I; in Formula I, 0.73≤γ≤14.00, γ is the thermal safety factor of the high-nickel ternary positive electrode material, α is the cross-sectional porosity of the high-nickel ternary positive electrode material, D104 is a parameter in the XRD test of the high-nickel ternary positive electrode material, and K is the thermal conductivity of the high-nickel ternary positive electrode material. The high-nickel ternary positive electrode material provided by the present invention identifies important factors affecting the thermal safety of the ternary positive electrode material by measuring its thermal conductivity K, D104 value in XRD, and porosity α. At the same time, by controlling these parameters and satisfying the relationship shown in Formula I, corresponding materials are prepared for verification. In addition, the high-nickel ternary positive electrode material is improved by coating with a coating material having low thermal conductivity, and the thermal conductivity of the material after coating is tested. The results show that as the coating amount of the coating material increases, the thermal conductivity of the ternary positive electrode material decreases overall and has better thermal safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is the cross-sectional pore distribution diagram of sample A;

[0028] Figure 2is the cross-sectional pore distribution diagram of sample B;

[0029] Figure 3 is the cross-sectional pore distribution diagram of sample C;

[0030] Figure 4 is the cross-sectional pore distribution diagram of sample D;

[0031] Figure 5 is the cross-sectional pore distribution diagram of sample E;

[0032] Figure 6 is the surface SEM image of sample F;

[0033] Figure 7 is the surface SEM image of sample G;

[0034] Figure 8 is the surface SEM image of sample H;

[0035] Figure 9 Surface SEM image of sample 1;

[0036] Figure 10 Comparison of DSC data of samples A to E;

[0037] Figure 11 Comparison of DSC data of samples A, F, G and H;

[0038] Figure 12 This is the DSC data diagram of sample 1. DETAILED DESCRIPTION

[0039] The present invention provides a high-nickel ternary cathode material with high thermal safety. The chemical formula of the high-nickel ternary cathode material is:

[0040] LiNi a Co b Mn c M d Q e O2,

[0041] Among them, 0.8<a<0.95, b<0.2, c<0.2, d<0.1, a+b+c+d+e=1,

[0042] M is a doping element, selected from one or more of Sr, Ti, Al, Zr, Y, Ba, Mg, and Mo,

[0043] Q is a coating element, selected from one or both of Sr and Ti,

[0044] The high nickel ternary cathode material satisfies the relationship shown in Formula I:

[0045] γ=α*D104 / K Formula I

[0046] In formula I, 0.73≤γ≤14.00, γ is the thermal safety factor of the high nickel ternary positive electrode material, α is the cross-sectional porosity of the high nickel ternary positive electrode material, D104 is a parameter in the XRD test of the high nickel ternary positive electrode material, and K is the thermal conductivity of the high nickel ternary positive electrode material.

[0047] In the present invention, the chemical formula of the high nickel ternary positive electrode material is:

[0048] LiNi a Co b Mn c M d Q e O2,

[0049] Here, 0.8<a<0.95, b<0.2, c<0.2, d<0.1, a+b+c=d+e=1. Moreover, b, c, and d are not zero.

[0050] M is a doping element, selected from one or more of Sr, Ti, Al, Zr, Y, Ba, Mg, and Mo, preferably Al, Mo, Sr, and Zr.

[0051] Q is a coating element, selected from one or both of Sr and Ti, preferably Sr and Ti.

[0052] In the present invention, the high nickel ternary cathode material comprises a core and a coating layer.

[0053] Wherein, the chemical formula of the core is LiNi a Co b Mn c M d O2

[0054] The coating layer is an oxide containing the element Q, and the thermal conductivity of the coating layer is ≤0.2 W / (m·K). The present invention can reduce the overall thermal conductivity of the ternary material by coating the material with low thermal conductivity.

[0055] In the present invention, the high nickel ternary cathode material satisfies the relationship shown in Formula I:

[0056] γ=α*D104 / K Formula I

[0057] In Formula I, γ is the thermal safety factor of the high-nickel ternary positive electrode material; in the present invention, the γ value is controlled between 0.73 and 14.00. When γ is lower than 0.73, the DSC peak temperature will be lower than 213°C, and the thermal safety of the high-nickel ternary positive electrode material is poor. When the γ value is between 0.73 and 14.00, the high-nickel ternary positive electrode material has higher thermal safety. Preferably, the γ value is controlled between 1.07 and 14.00, and the high-nickel ternary positive electrode material has higher thermal safety. Further preferably, the γ value is controlled between 1.45 and 13.13, and more preferably, the γ value is controlled between 7.74 and 13.13.

[0058] α is the cross-sectional porosity of the high-nickel ternary cathode material. High porosity can reduce the overall thermal conductivity of the high-nickel ternary cathode material, delaying the inward transfer of heat generated by side reactions on the material surface, effectively improving the stability of the material's internal structure and inhibiting the occurrence of internal side reactions, thereby improving the thermal safety of the material. In the present invention, 1% ≤ α ≤ 5%. Preferably, α is 1%, 2%, 3%, 4%, 5%, or any value between 1% and 5%.

[0059] D104 is a parameter measured in XRD testing of high-nickel ternary cathode materials. An increase in the D104 parameter of the crystal envelope reduces the material's phonon thermal conductivity. In the present invention, 45 ≤ D104 ≤ 70. Preferably, D104 is 45, 50, 55, 60, 65, 70, or any value between 45 and 70.

[0060] K is the thermal conductivity of the high nickel ternary positive electrode material, 0.1W / (m·K)≤K≤0.6W / (m·K), preferably, K is 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, or any value between 0.1 and 0.6W / (m·K).

[0061] The high-nickel ternary positive electrode material provided by the present invention has low thermal conductivity. When the material reacts with the electrolyte, the heat release is correspondingly delayed, thereby mitigating the occurrence of side reactions.

[0062] The present invention also provides a method for preparing the above-mentioned high-nickel ternary positive electrode material, comprising the following steps:

[0063] A) Ni a Co b Mn c (OH)2, a lithium source and a compound containing an M element are mixed and sintered in an oxygen atmosphere to obtain a sintered product;

[0064] B) washing and drying the sintered product, mixing it with a compound containing the Q element, and sintering it in an oxygen atmosphere to obtain a high-nickel ternary positive electrode material.

[0065] The present invention firstly prepares a ternary hydroxide precursor Ni a Co b Mn c (OH)2, a lithium source and a compound containing an M element are mixed to obtain a mixture.

[0066] Wherein, the lithium source is selected from LiOH;

[0067] The compound containing the M element is selected from one or more of Al(OH)3, Al2O3, SrO, TiO2, ZrO2, Zr(OH)4, Y2O3, BaCO3, MgO, and MoO3;

[0068] Ternary hydroxide precursor Ni a Co b Mn c The molar ratio of (OH)2 to lithium source is 1:1.04;

[0069] Ternary hydroxide precursor Ni a Co b Mn c The molar ratio of (OH)2 to the compound containing the M element is 1:d, wherein d is less than 0.1, and preferably is between 0.01 and 0.04.

[0070] The present invention has no particular limitation on the mixing method, and any mixing method known to those skilled in the art may be used.

[0071] Then, the mixture is sintered under oxygen atmosphere conditions to obtain a sintered product.

[0072] Wherein, the sintering temperature is 740℃~820℃, preferably 740, 760, 780, 800, 820, or any value between 740℃~820℃, and the sintering time is 10~15 hours, preferably 10, 11, 12, 13, 14, 15, or any value between 10~15 hours.

[0073] Next, the sintered product is cooled, crushed and sieved, then washed with water and dried, and then mixed with a compound containing the Q element and sintered under oxygen atmosphere to obtain a high-nickel ternary positive electrode material.

[0074] Wherein, the compound containing Q element is selected from TiO2, SrO, and SrTiO3.

[0075] The sintering temperature is 350-500° C., preferably 350, 400, 450, 500, or any value between 350-500° C., and the sintering time is 8-12 hours, preferably 8, 9, 10, 11, 12, or any value between 8-12 hours.

[0076] The present invention also provides a lithium-ion battery comprising the above-mentioned high-nickel ternary positive electrode material.

[0077] The high-nickel ternary positive electrode material provided by the present invention has a relatively high DSC peak temperature, and thus has high thermal safety. The characterization of the thermal safety performance in the present invention is based on the peak value of the DSC test.

[0078] The high-nickel ternary positive electrode material provided by the present invention identifies important factors affecting the thermal safety of the ternary positive electrode material by measuring its thermal conductivity K, D104 value in XRD, and porosity α. At the same time, by controlling these parameters and satisfying the relationship shown in Formula I, corresponding materials are prepared for verification. In addition, the high-nickel ternary positive electrode material is improved by coating with a coating material having low thermal conductivity, and the thermal conductivity of the material after coating is tested. The results show that as the coating amount of the coating material increases, the thermal conductivity of the ternary positive electrode material decreases overall and has better thermal safety.

[0079] In order to further understand the present invention, the high-nickel ternary positive electrode material with high thermal safety, its preparation method and application provided by the present invention are described below in conjunction with the embodiments. The protection scope of the present invention is not limited by the following embodiments.

[0080] Example

[0081] 1) Sample A is LiNi 0.908 Co 0.048 Mn 0.029 M 0.015 O2, M is Al, wherein α, D104, K and γ are 1%, 45, 0.62 and 0.73 respectively.

[0082] Preparation method:

[0083] ① Ni hydroxide 0.92 Co 0.05 Mn 0.03 (OH)2, and LiOH in a molar ratio of 1:1.04 and an additive Al(OH)3 with a molar ratio of 0.015;

[0084] ② The uniformly mixed materials were sintered at 740°C for 15 hours in an oxygen atmosphere, cooled, crushed and sieved.

[0085] 2) Sample B is LiNi 0.908 Co 0.048 Mn 0.029 M 0.015 O2, M is Sr, wherein α, D104, K and γ are 2%, 60, 0.41 and 2.93 respectively.

[0086] Preparation method:

[0087] ① Ni hydroxide 0.92 Co 0.05 Mn 0.03 (OH)2 and LiOH were mixed in a molar ratio of 1:1.04 and an additive SrO with a molar ratio of 0.015;

[0088] ② The uniformly mixed materials were sintered at 780°C for 15 hours in an oxygen atmosphere, cooled, crushed and sieved.

[0089] 3) Sample C is LiNi 0.908 Co 0.048 Mn 0.029 M 0.015 O2, M is Zr, wherein α, D104, K and γ are 3%, 70, 0.16 and 13.13 respectively.

[0090] Preparation method:

[0091] ① Ni hydroxide 0.92 Co 0.05 Mn 0.03 (OH)2 and LiOH were mixed in a molar ratio of 1:1.04 and an additive of ZrO2 with a molar ratio of 0.015;

[0092] ② The uniformly mixed materials were sintered at 820°C for 15 hours in an oxygen atmosphere, cooled, crushed and sieved.

[0093] 4) Sample D is LiNi 0.908 Co 0.048 Mn 0.029 M 0.015 O2, M is Y, wherein α, D104, K and γ are 4%, 60, 0.31 and 7.74 respectively.

[0094] Preparation method:

[0095] ① Ni hydroxide 0.92 Co 0.05 Mn 0.03 (OH)2 and LiOH were mixed in a molar ratio of 1:1.04 and an additive Y2O3 with a molar ratio of 0.015;

[0096] ② The uniformly mixed materials were sintered at 780°C for 15 hours in an oxygen atmosphere, cooled, crushed and sieved.

[0097] 5) Sample E is LiNi 0.908 Co 0.048 Mn 0.029 M 0.015O2, M is Mo, wherein α, D104, K and γ are 3%, 70, 0.25 and 8.4 respectively.

[0098] Preparation method:

[0099] ① Ni hydroxide 0.92 Co 0.05 Mn 0.03 (OH)2 and LiOH were mixed in a molar ratio of 1:1.04 and an additive MoO3 with a molar ratio of 0.015;

[0100] ② The uniformly mixed materials were sintered at 800°C for 15 hours in an oxygen atmosphere, cooled, crushed and sieved.

[0101] 6) Based on sample A, 1000ppm of Q coating agent was coated to obtain sample F which is LiNi 0.9075 Co 0.048 Mn 0.029 M 0.015 Q 0.0005 O2, M is Al, Q is Sr, wherein α, D104, K and γ are 1%, 45, 0.53, and 0.85 respectively.

[0102] Preparation method: Sample A was washed with water at a water-to-material ratio of 1:1, centrifuged and dried at 140°C for 12 hours, then uniformly mixed with 1000 ppm of SrO, and then sintered at 500°C for 12 hours in an oxygen atmosphere to obtain sample F.

[0103] 7) Based on sample A, 3000ppm of Q coating agent was coated to obtain sample G, which is LiNi 0.9065 Co 0.048 Mn 0.029 M 0.015 Q 0.0015 O2, M is Al, Q is Ti, wherein α, D104, K and γ are 1%, 45, 0.42, and 1.07 respectively.

[0104] Preparation method: Sample A was washed with water at a water-to-material ratio of 1:1, then centrifuged and dried at 140°C for 12 hours, then evenly mixed with 3000ppm of TiO2, and then sintered at 500°C in an oxygen atmosphere for 12 hours to obtain sample G.

[0105] 8) Based on sample A, 5000ppm of Q coating agent was coated to obtain sample H, which is LiNi 0.9055 Co 0.048 Mn 0.029 M 0.015 Q 0.0025O2, M is Al, Q is Sr and Ti, among which α, D104, K and γ are 1%, 45, 0.31, and 1.45 respectively.

[0106] Preparation method: Sample A was washed with water at a water-to-material ratio of 1:1, centrifuged and dried at 140°C for 12 hours, then uniformly mixed with 5000ppm of SrTiO3, and then sintered at 500°C in an oxygen atmosphere for 12 hours to obtain sample H.

[0107] Comparative Example

[0108] 1) Sample I is LiNi 0.92 Co 0.05 Mn 0.03 O2, wherein α, D104, K and γ are 1%, 40, 0.86 and 0.47 respectively.

[0109] Preparation method:

[0110] ① Ni hydroxide 0.92 Co 0.05 Mn 0.03 (OH)2 and LiOH were mixed in a molar ratio of 1:1.04;

[0111] ② The uniformly mixed materials were sintered at 740°C for 15 hours in an oxygen atmosphere, cooled, crushed and sieved.

[0112] The performance tests of the samples A to I obtained above were carried out as follows:

[0113] 1.DSC test:

[0114] ① The positive electrode material and acetylene black were dispersed in a 5% PVDF NMP solution at a mass ratio of 98:2 and stirred for 20 minutes, wherein the concentration of the positive electrode material was 60%.

[0115] ② The obtained slurry was evenly coated on aluminum foil and dried in a vacuum drying oven at 110°C for 4 hours.

[0116] ③ Cut the dried electrode into discs with a diameter of 15 mm, and assemble and seal the positive electrode shell, electrode, electrolyte (EC / DMC / EMC volume ratio 1:1, LiPF6 concentration is 1 mol / L), diaphragm (CelgardPP / PE / PP three-layer composite film), lithium sheet, electrolyte, nickel foam, and negative electrode shell in a glove box to obtain a battery.

[0117] ④ The obtained battery was left to stand for 24 hours and then charged with a current of 0.1C.

[0118] ⑤ Disassemble the charged battery in a glove box, clean and dry the obtained electrode with NMP, and then perform DSC testing. In the glove box, take 2-3 mg of the positive electrode and place it at the bottom of a crucible. Drop 1.7 mg of a 1 mol / L LiPF6 solution (the solvent includes EC and DMC in a volume ratio of 1:1) to evenly distribute the LiPF6 solution on the surface of the electrode. Seal the crucible in a special mold. Place the sealed crucible in a differential scanning calorimeter, introduce nitrogen, and test at a heating rate of 10°C / min. The maximum temperature is set to 350°C.

[0119] 2. Thermal conductivity test: using laser thermal conductivity meter LFA (Netzsch, Germany)

[0120] 3. Porosity test: The sample is subjected to an ion milling instrument to obtain a smooth surface cross-section for SEM testing, and the porosity is obtained after software processing.

[0121] Samples A, B, C, D, and E have crystal parameters D104 and thermal conductivity K with different porosities α. The increase in D104 increases the interlayer spacing of the transition metal layer of the material. At the same time, the space of the Li layer is compressed, which restricts the transmission of Li ions and reduces the ionic thermal conductivity. In addition, the increase in the lattice spacing reduces the phonon thermal conductivity, resulting in a decrease in the overall thermal conductivity. The higher the porosity between the primary particles in the secondary spheres, the more heat is hindered from diffusing from the surface of the material to the inside, which reduces the overall thermal conductivity and inhibits the spread of thermal deterioration from the outside of the material to the inside. Figures 1 to 5 These are the cross-sectional pore distribution diagrams of samples AE, respectively.

[0122] Samples FH are materials of sample A coated with 1000ppm, 3000ppm and 5000ppm of Q coating agent respectively. By coating with Q coating material with low thermal conductivity and changing the coating amount, the overall thermal conductivity of the material can be reduced, thereby reducing the thermal conductivity of the material and reducing the impact of external thermal reactions on the secondary ball. In addition, the coating layer has a certain insulating effect on the material and the electrolyte, which can effectively inhibit side reactions on the surface of the material, reduce heat release and collapse of the material structure, and thus improve the thermal safety of the material. Figures 6-9 Surface SEM images of sample FI, Figures 10-12 Comparison of DSC data of different materials. Figure 10 In the figure, the samples from left to right are A, B, D, E and C according to the peak position; Figure 11 In the figure, the samples from left to right are A, F, G, and H according to the peak positions. Figure 12 This is the DSC data diagram of sample 1.

[0123] Table 1 shows the α, D104, K, γ and the corresponding DSC peak values ​​of materials A to I.

[0124] Table 1

[0125]

[0126]

[0127] When γ is lower than 0.73, the DSC peak temperature will be lower than 213°C, and the thermal safety of the high-nickel ternary cathode material is poor. When the γ value is ≥1.07, the DSC peak temperature is ≥221°C, which has better thermal safety performance. When the γ value is ≥7.74, the DSC peak temperature is ≥233°C, which has very excellent thermal safety performance. When the γ value is =13.13, the DSC peak temperature is as high as 240°C.

[0128] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A high-nickel ternary cathode material with high thermal safety, characterized in that: The chemical formula of the high nickel ternary cathode material is: LiNi a Co b Mn c M d Q e O2, Among them, 0.8<a<0.95, b<0.2, c<0.2, d is 0.01~0.04, a+b+c+d+e=1, M is a doping element, selected from one or more of Sr, Ti, Al, Zr, Y, Ba, Mg, and Mo, Q is a coating element, selected from one or both of Sr and Ti, The high nickel ternary cathode material satisfies the relationship shown in Formula I: γ=α*D104 / K Formula I In formula I, 0.73≤γ≤14.00, γ is the thermal safety factor of the high nickel ternary positive electrode material, α is the cross-sectional porosity of the high nickel ternary positive electrode material, D104 is a parameter in the XRD test of the high nickel ternary positive electrode material, and K is the thermal conductivity of the high nickel ternary positive electrode material; 45≤D104≤70; 1%≤α≤5%; 0.1W / (m·K)≤K≤0.6W / (m·K).

2. The high nickel ternary cathode material according to claim 1, characterized in that The invention comprises a core and a cladding layer, wherein the thermal conductivity of the cladding layer is less than or equal to 0.2 W / (m·K).

3. A method for preparing a high-nickel ternary positive electrode material according to any one of claims 1 to 2, characterized in that: The following steps are involved: A) Ni a Co b Mn c (OH)2, a lithium source and a compound containing an M element are mixed and sintered in an oxygen atmosphere to obtain a sintered product; B) washing and drying the sintered product, mixing it with a compound containing the Q element, and sintering it in an oxygen atmosphere to obtain a high-nickel ternary positive electrode material.

4. The preparation method according to claim 3, characterized in that The lithium source is selected from LiOH; The compound containing the M element is selected from one or more of Al(OH)3, Al2O3, SrO, TiO2, ZrO2, Zr(OH)4, Y2O3, BaCO3, MgO, and MoO3; The compound containing the Q element is selected from TiO2, SrO, and SrTiO3.

5. The preparation method according to claim 3, characterized in that In step A), the sintering temperature is 740° C. to 820° C., and the sintering time is 10 to 15 hours.

6. The preparation method according to claim 3, characterized in that In step B), the sintering temperature is 350-500° C. and the sintering time is 8-12 hours.

7. A lithium-ion battery, characterized in that: The invention comprises the high-nickel ternary positive electrode material according to any one of claims 1 to 2 or the high-nickel ternary positive electrode material prepared by the preparation method according to any one of claims 3 to 6.

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