A ternary cathode material, its preparation method, and a lithium battery

Abstract

This invention relates to the field of lithium-ion battery technology, specifically to a ternary cathode material, its preparation method, and a lithium battery. The ternary cathode material includes a first particle and a second particle; the first particle has a single-crystal structure, with a first dopant element doped in its bulk phase, and its surface is sequentially coated with a first coating layer and a high-entropy oxide coating layer; the second particle has a polycrystalline structure, with a second dopant element doped in its bulk phase, and its surface is sequentially coated with a second coating layer and a high-entropy oxide coating layer; the first particle and the second particle each independently have the chemical formula Li. x Ni a Co b Mn 1‑a‑b O2, where 1.0≤x≤1.1, 0<a<1, 0<b<1, a+b<1. By performing bulk doping and surface coating on single-crystal and polycrystalline particles respectively, followed by mixing and applying a secondary coating of high-entropy oxides, the rate performance, compaction density, and cycle performance of the ternary cathode material are synergistically improved.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion battery technology, and more specifically, to a ternary cathode material, its preparation method, and a lithium battery. Background Technology

[0002] Lithium resources have been hailed as "white oil" in the 21st century, thanks to the rapid development of lithium batteries and the continuous expansion of their applications, extending from consumer electronics to power batteries, drones, and robots. With the development of the low-altitude economy, higher demands are being placed on the energy density, rate performance, and safety performance of lithium batteries, further driving the iterative upgrades of cathode materials.

[0003] While lithium iron phosphate materials possess excellent cycle stability and safety, their low energy density and poor low-temperature performance make them unsuitable for high-energy-density applications. Ternary materials, due to their higher energy density and better cycle performance, show great market potential in the low-altitude economy. Currently, the development of ternary materials mainly follows two technical paths: one is the medium-nickel, low-cobalt, high-voltage route, and the other is the high-nickel, low-cobalt route.

[0004] However, the medium-nickel, low-cobalt system faces challenges such as electrolyte decomposition and increased interfacial side reactions after the discharge cutoff voltage is increased to 4.4-4.5V. Simultaneously, the structural stability of the cathode material decreases under deep delithiation, hindering its further development. While high-nickel ternary materials possess higher energy density and better cycle performance, and their charge-discharge windows are well-suited to commercial electrolytes, significant challenges remain in practical applications: increased lithium-nickel mixing tendency and insufficient structural stability lead to safety hazards that urgently need to be addressed. Furthermore, to meet the demands of high-rate applications, systematic modification research based on the intrinsic structure and interfacial properties of the materials is urgently needed.

[0005] In view of this, the present invention is hereby proposed. Summary of the Invention

[0006] The purpose of this invention is to provide a ternary cathode material, its preparation method, and a lithium battery. By performing gradient doping and surface coating on single-crystal and polycrystalline particles respectively, and then mixing and applying a high-entropy oxide secondary coating, the structural stability, interfacial inertness, and charge transport dynamics are synergistically improved, thereby enhancing the rate performance, compaction density, and cycle performance of the cathode material.

[0007] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted: A ternary cathode material includes: a first particle and a second particle; The first particle has a single crystal structure, and the bulk phase of the first particle is doped with a first doping element, and its surface is sequentially coated with a first coating layer and a high-entropy oxide coating layer. The second particle has a polycrystalline structure; the bulk phase of the second particle is doped with a second doping element, and its surface is sequentially coated with a second coating layer and a high-entropy oxide coating layer. The first particle and the second particle each independently have the chemical formula Li. x Ni a Co b Mn 1-a-b O2, where 1.0≤x≤1.1, 0<a<1, 0<b<1, a+b<1.

[0008] The preparation method of the ternary cathode material as described above includes the following steps: S1. Prepare a first particle, dope it with a first doping element in its bulk phase, and coat it with a first coating layer to obtain a single-crystal ternary material; A second particle is prepared, and a second doping element is doped into its bulk phase. A second coating layer is then coated on its surface to obtain a polycrystalline ternary material. S2. The single-crystal ternary material, the polycrystalline ternary material and the high-entropy oxide are mixed and sintered, and then crushed, sieved and demagnetized to obtain the ternary cathode material.

[0009] A lithium battery comprising the ternary cathode material as described above.

[0010] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention employs bulk gradient doping and surface coating of both single-crystal and polycrystalline particles to stabilize the crystal structure of the material, suppress side reactions with the electrolyte, and construct a highly efficient conductive network. The mixing of single-crystal and polycrystalline particles increases the tap density of the electrode, thereby improving the energy density. A secondary coating of the single-crystal and polycrystalline particles with high-entropy oxides constructs a high-entropy oxide functional layer on the particle surface, which significantly promotes lithium-ion migration at the interface, reduces ion transport resistance, and thus improves rate performance. This invention synergistically improves the rate performance, tap density, and cycle stability of ternary cathode materials through bulk doping, surface coating, mixing of single-crystal and polycrystalline particles, and the construction of a high-entropy oxide functional layer. Attached Figure Description

[0011] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0012] Figure 1This is a schematic diagram of the synthesis route of the single-crystal ternary material provided in the embodiments of the present invention; Figure 2 This is a schematic diagram of the synthesis route of polycrystalline ternary materials provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the synthesis route of the ternary cathode material provided in the embodiments of the present invention; Figure 4 This is a SEM image of the single-crystal ternary material in Embodiment 1 of the present invention; Figure 5 This is a SEM image of the polycrystalline ternary material in Embodiment 1 of the present invention; Figure 6 This is a SEM image of the ternary cathode material prepared in Example 1 of the present invention; Figure 7 This is a charge-discharge curve of a half-cell assembled with ternary cathode material in Embodiment 1 of the present invention; Figure 8 The cycling performance curves are for the full cells assembled with the cathode materials in Example 1 and Comparative Example 7 of this invention. Detailed Implementation

[0013] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0014] A first aspect of the present invention provides a ternary cathode material, comprising: a first particle and a second particle; The first particle has a single crystal structure, and the bulk phase of the first particle is doped with a first doping element. The surface of the first particle is sequentially coated with a first coating layer and a high-entropy oxide coating layer. The second particle has a polycrystalline structure; the bulk phase of the second particle is doped with a second doping element, and the surface of the second particle is sequentially coated with a second coating layer and a high-entropy oxide coating layer. The first and second particles each independently possess the chemical formula Li. x Ni a Co b Mn 1-a-b O2, where 1.0≤x≤1.1, 0<a<1, 0<b<1, a+b<1.

[0015] This invention improves the compaction density and energy density of the electrode by mixing single-crystal and polycrystalline particles; bulk doping and surface coating of single-crystal and polycrystalline particles respectively stabilize the crystal structure of the material, suppress side reactions with the electrolyte, and improve the cycling performance of the material; coating the outer layer of the particles with a high-entropy oxide functional layer induces lithium-ion migration, reduces ion transport resistance, and thus improves rate performance; through multi-faceted synergy, the energy density, cycle stability, and rate performance are simultaneously improved.

[0016] In some specific embodiments of the present invention, the first doping element includes Al, Zr, and Y, and its function is to stabilize the crystal structure, wherein Zr 4+ It can reduce Li+ / Ni 2+ Mixed arrangement, with some Zr entering the lithium layer to act as a support; Al 3+ Stabilizes oxygen in the material, inhibiting oxygen evolution; Y 3+ Doping can effectively suppress harmful phase transitions in ternary materials during charge and discharge: it enhances the interlayer coupling between the Li layer and the transition metal (TM), delays the H1-H3 phase transition under high voltage, and reduces the generation of microcracks; it also improves the structural stability of the material, thereby improving cycle performance.

[0017] In some specific embodiments of the present invention, the first doping element is gradient-distributed in the first particle, and the gradient doping of Al, Zr and Y can effectively enhance the structural stability of the ternary material after delithiation.

[0018] In some specific embodiments of the present invention, the contents of Al, Zr and Y in the first dopant element in the first particle are independently controlled between 100 and 10000 ppm. For example, they can be any one value or a range of any two values ​​from 100 ppm, 500 ppm, 1000 ppm, 3000 ppm, 5000 ppm, 8000 ppm and 10000 ppm.

[0019] In some specific embodiments of the present invention, the first coating layer comprises an oxide of Al, W, and Co, wherein W in the tungsten oxide 6+ Ion coating into the surface of ternary materials can increase the electronic conductivity of the material itself. On the other hand, the nanoscale tungsten oxide coating can build a highly efficient conductive network on the material surface. Alumina utilizes its stable chemical inertness and high mechanical strength to construct a robust physical barrier against electrolyte corrosion and to alleviate structural strain. Cobalt oxide coating can consume Li2CO3 / LiOH on the material surface, reduce surface alkalinity, and also act as a protective layer to slow down the dissolution of metal ions such as Mn and Ni in the electrolyte.

[0020] In some specific embodiments of the present invention, in the first coating layer, the contents of Al and W in the first particles are each independently 100~20000ppm, for example, they can be any one value or a range of any two values ​​among 100ppm, 500ppm, 1000ppm, 3000ppm, 5000ppm, 10000ppm, and 20000ppm; the contents of Co in the first particles are 100~50000ppm, for example, they can be any one value or a range of any two values ​​among 100ppm, 500ppm, 1000ppm, 5000ppm, 10000ppm, 30000ppm, and 50000ppm.

[0021] In some specific embodiments of the present invention, the second doping element includes Al, Zr, and Y, and its function is to stabilize the crystal structure, wherein Zr 4+ It can reduce Li+ / Ni 2+ Mixed arrangement, with some Zr entering the lithium layer to act as a support; Al 3+ Stabilizes oxygen in the material, inhibiting oxygen evolution; Y 3+ Doping can effectively suppress harmful phase transitions in ternary materials during charge and discharge: it enhances the interlayer coupling between the Li layer and the transition metal (TM), delays the H1-H3 phase transition under high voltage, and reduces the generation of microcracks; it also improves the structural stability of the material, thereby improving cycle performance.

[0022] In some specific embodiments of the present invention, the second doping element is gradient-distributed in the second particle, and the gradient doping of Al, Zr and Y can effectively enhance the structural stability of the ternary material after delithiation.

[0023] In some specific embodiments of the present invention, the contents of Al, Zr and Y in the second dopant element in the second particle are independently controlled between 100 and 10000 ppm. For example, they can be any one value or a range of any two values ​​from 100 ppm, 500 ppm, 1000 ppm, 3000 ppm, 5000 ppm, 8000 ppm and 10000 ppm.

[0024] In some specific embodiments of the present invention, the second coating layer includes oxides of both Al and B. The surface is coated with boron oxide and aluminum oxide to form a dense and uniform inorganic protective layer, which effectively isolates the positive electrode material from direct contact with the electrolyte, thereby greatly reducing side reactions such as oxidation and decomposition of the electrolyte on the surface of the positive electrode material during charging and discharging. Furthermore, the boron oxide coating can also strengthen the bonding force between primary particles and suppress secondary sphere fragmentation caused by volume changes during cycling.

[0025] In some specific embodiments of the present invention, in the second coating layer, the contents of Al and B in the second particles are each independently 100~20000ppm. For example, they can be any one value or a range of any two values ​​from 100ppm, 500ppm, 1000ppm, 3000ppm, 5000ppm, 10000ppm, 20000ppm.

[0026] In some specific embodiments of the present invention, the mass ratio of the first particle and the second particle is (1~10):(1~10), for example, it can be any one value or a range of any two values ​​among 1:10, 1:5, 1:3, 1:1, 3:1, 5:1, and 10:1.

[0027] In some specific embodiments of the present invention, the high-entropy oxide accounts for 0.1% to 30% of the total mass of the first particle and the second particle. For example, it can be any one value or a range of any two values ​​from 0.1%, 1%, 5%, 10%, 20%, and 30%. Too high or too low a proportion will lead to a decrease in electrochemical performance.

[0028] In some specific embodiments of the present invention, the general formula of the high-entropy oxide used is Li. a V b Ti c Al d Co e Zr f O x , where 0 < a, b, c, d, e, f < 0.25, for example, a, b, c, d, e, f can be any one value or a range of any two values ​​from 0.05, 0.11, 0.15, 0.21, 0.25; 0 < x < 3, for example, can be any one value or a range of any two values ​​from 0.5, 1.5, 2, 2.5.

[0029] In some specific embodiments of the present invention, the preparation method of high-entropy oxide includes: mixing vanadium source, titanium source, aluminum source, cobalt source, zirconium source, lithium source and solvent, and performing sand milling, spray drying, sintering and crushing.

[0030] In some specific embodiments of the present invention, the vanadium source includes vanadium pentoxide and / or vanadate.

[0031] In some specific embodiments of the present invention, the titanium source includes at least one of titanium oxide, titanium chloride, and titanium sulfate.

[0032] In some specific embodiments of the present invention, the aluminum source includes aluminum oxide and / or aluminum hydroxide.

[0033] In some specific embodiments of the present invention, the cobalt source includes cobalt oxide and / or cobalt nitrate.

[0034] In some specific embodiments of the present invention, the zirconium source includes at least one of zirconium oxide, zirconium sulfate, and zirconium chloride.

[0035] In some specific embodiments of the present invention, the lithium source includes at least one of lithium carbonate, lithium hydroxide, and lithium oxalate.

[0036] In some specific embodiments of the present invention, after sand milling, the particle size D50 of the slurry is 0.2~0.35μm. For example, it can be any one value or a range of any two values ​​among 0.2μm, 0.25μm, 0.3μm, and 0.35μm.

[0037] In some specific embodiments of the present invention, the grinding media used in the sand milling process is zirconium balls with a size of 0.1~0.15mm, for example, any one value or a range of any two values ​​among 0.1mm, 0.12mm, 0.14mm, and 0.15mm; the filling rate of the zirconium balls is 70%~80%, for example, any one value or a range of any two values ​​among 70%, 72%, 75%, 78%, and 80%; the solvent of the sand milling slurry includes deionized water and / or ethanol; the sand milling speed is 1500~2800rpm, for example, any one value or a range of any two values ​​among 1500rpm, 1800rpm, 2000rpm, 2300rpm, 2500rpm, and 2800rpm; and the sand milling time is 2~5h, for example, any one value or a range of any two values ​​among 2h, 3h, 4h, and 5h.

[0038] In some specific embodiments of the present invention, the inlet air temperature of the spray dryer is 180~230°C, for example, it can be any one value or a range of any two values ​​among 180°C, 200°C, 220°C, and 230°C; the outlet air temperature is 105~110°C, for example, it can be any one value or a range of any two values ​​among 105°C, 107°C, 109°C, and 110°C.

[0039] In some specific embodiments of the present invention, the atomization method of the spray drying process includes airflow atomization or centrifugal atomization, preferably centrifugal atomization. As an example, the centrifugal speed of the atomizer is 300~350Hz.

[0040] In some specific embodiments of the present invention, when preparing the high-entropy oxide, sintering is carried out in an oxygen-containing atmosphere (such as an air atmosphere or an oxygen atmosphere); the sintering temperature is 600~1200℃, for example, it can be any one value or a range of any two values ​​among 600℃, 800℃, 1000℃, and 1200℃; preferably 1100~1200℃; the sintering time is 12~16h, for example, it can be any one value or a range of any two values ​​among 12h, 13h, 14h, 15h, and 16h.

[0041] In some specific embodiments of the present invention, the particle size D50 of the high-entropy oxide after crushing is 0.8~1.5μm. For example, it can be any one value or a range of any two values ​​among 0.8μm, 1.0μm, 1.2μm, and 1.5μm.

[0042] like Figure 3 As shown, a second aspect of the present invention provides a method for preparing a ternary cathode material according to any one of the foregoing embodiments, comprising the following steps: S1. Prepare a first particle, dope it with a first doping element in its bulk phase, and coat it with a first coating layer to obtain a single-crystal ternary material (single-crystal particle). A second particle is prepared, and a second doping element is doped into its bulk phase. A second coating layer is then coated on its surface to obtain a polycrystalline ternary material (polycrystalline particle). S2. The single-crystal ternary material, the polycrystalline ternary material and the high-entropy oxide are mixed and sintered, and then crushed, sieved and demagnetized to obtain the ternary cathode material.

[0043] The method of this invention performs bulk doping and surface coating on single-crystal particles and polycrystalline particles respectively, which can improve the crystal stability of the material and suppress its side reactions with the electrolyte. Then, the single-crystal particles and polycrystalline particles are mixed and high-entropy oxides are introduced for surface co-coating to improve the compaction density and rate performance. A ternary cathode material with high rate performance, high compaction density and excellent cycle stability is obtained.

[0044] like Figure 1 As shown, in some specific embodiments of the present invention, step S1, the method for preparing single-crystal ternary materials includes: (i) A nickel-cobalt-manganese compound is mixed with a lithium salt and a portion of the first dopant, and then sintered once to obtain the first pre-lithiation material; (ii) The first pre-lithiation material is mixed with the remaining first dopant, and then sintered twice. After crushing and sieving to remove magnetism, the first semi-finished product is obtained. (iii) The first semi-finished product is mixed with the first coating agent and sintered three times. After crushing, sieving and demagnetizing, a single-crystal ternary material is obtained.

[0045] The present invention adds a first dopant in stages, achieves bulk gradient doping through two sintering processes, and then mixes it with a first coating agent for a third sintering process to achieve coating. After three sintering processes, a single crystal particle with bulk gradient doping and surface coating is formed.

[0046] In some specific embodiments of the present invention, in step (i), the nickel cobalt manganese compound includes nickel cobalt manganese oxide and / or nickel cobalt manganese hydroxide.

[0047] In some specific embodiments of the present invention, in step (i), the lithium salt includes at least one of lithium carbonate, lithium hydroxide, and lithium acetate.

[0048] In some specific embodiments of the present invention, in step (i), the first dopant includes a zirconium dopant, an aluminum dopant, and a yttrium dopant; wherein the zirconium dopant includes at least one of zirconium oxide, zirconium carbonate, zirconium nitrate, and zirconium sulfate; and / or, the aluminum dopant includes aluminum oxide and / or aluminum hydroxide; and / or, the yttrium dopant includes at least one of yttrium oxide, yttrium chloride, and yttrium fluoride.

[0049] In some specific embodiments of the present invention, in step (i), the amount of Zr, Al and Y added in the first dopant is independently 100~5000ppm, for example, it can be any one value or a range of any two values ​​among 100ppm, 300ppm, 500ppm, 1000ppm, 3000ppm and 5000ppm.

[0050] In some specific embodiments of the present invention, in step (i), the material mixing speed is 50~1000 rpm, the mixing time is 5~60 min, the mixing temperature is ≤50℃, and the mixing equipment includes, but is not limited to, high-speed mixer, plow mixer, batch mixer, etc.

[0051] In some specific embodiments of the present invention, in step (i), the first sintering is carried out in an oxygen-containing atmosphere (such as an air atmosphere or an oxygen atmosphere), and the temperature of the first sintering is 600~630°C. For example, it can be any one value or a range of any two values ​​among 600°C, 605°C, 610°C, 615°C, 620°C, 625°C, and 630°C. The time of the first sintering is 7~18h. For example, it can be any one value or a range of any two values ​​among 7h, 10h, 15h, and 18h.

[0052] In some specific embodiments of the present invention, in step (ii), the secondary sintering is carried out in an oxygen-containing atmosphere (such as an air atmosphere or an oxygen atmosphere), and the temperature of the secondary sintering is 800~900℃, for example, it can be any one value or a range of any two values ​​among 800℃, 820℃, 850℃, 880℃, and 900℃; the time of the secondary sintering is 20~30h, for example, it can be any one value or a range of any two values ​​among 20h, 22h, 25h, 28h, and 30h.

[0053] In some specific embodiments of the present invention, in step (ii), the amount of Zr, Al and Y added in the first dopant is independently 100~5000ppm, for example, it can be any one value or a range of any two values ​​among 100ppm, 300ppm, 500ppm, 1000ppm, 3000ppm and 5000ppm.

[0054] In some specific embodiments of the present invention, in step (iii), the first coating agent includes an aluminum coating agent, a tungsten coating agent, and a cobalt coating agent; wherein the aluminum coating agent includes aluminum oxide and / or aluminum hydroxide; and / or, the tungsten coating agent includes tungsten oxide and / or tungstic acid; and / or, the cobalt coating agent includes at least one of cobalt oxide, cobalt tetroxide, cobalt carbonate, and cobalt hydroxide.

[0055] In some specific embodiments of the present invention, in step (iii), the three sinterings are carried out in an oxygen-containing atmosphere (such as an air atmosphere or an oxygen atmosphere), and the temperature of the three sinterings is 600~800℃, for example, it can be any one value or a range of any two values ​​among 600℃, 650℃, 700℃, 750℃, and 800℃; the time of the three sinterings is 15~25h, for example, it can be any one value or a range of any two values ​​among 15h, 18h, 20h, 22h, and 25h.

[0056] like Figure 2 As shown, in some specific embodiments of the present invention, step S1, the method for preparing polycrystalline ternary materials includes: (a) A nickel-cobalt-manganese compound is mixed with a lithium salt and a portion of a second dopant, and then sintered once to obtain a second pre-lithiation material; (b) The second pre-lithiation material is mixed with the remaining second dopant, sintered twice, crushed, sieved and demagnetized to obtain the second semi-finished product; (c) After washing and drying the second semi-finished product, it is mixed with the second coating agent and sintered three times. After crushing, sieving and demagnetizing, polycrystalline ternary material is obtained.

[0057] The present invention adds a second dopant in stages, achieves bulk gradient doping through two sintering processes, and then mixes it with a first coating agent for a third sintering process to achieve coating. After three sintering processes, polycrystalline particles with bulk gradient doping and surface coating are formed.

[0058] In some specific embodiments of the present invention, in step (a), the nickel cobalt manganese compound includes nickel cobalt manganese oxide and / or nickel cobalt manganese hydroxide.

[0059] In some specific embodiments of the present invention, in step (a), the lithium salt includes at least one of lithium carbonate, lithium hydroxide, and lithium acetate.

[0060] In some specific embodiments of the present invention, in step (a), the second dopant includes a zirconium dopant, an aluminum dopant, and a yttrium dopant; wherein the zirconium dopant includes at least one of zirconium oxide, zirconium carbonate, zirconium nitrate, and zirconium sulfate; and / or, the aluminum dopant includes aluminum oxide and / or aluminum hydroxide; and / or, the yttrium dopant includes at least one of yttrium oxide, yttrium chloride, and yttrium fluoride.

[0061] In some specific embodiments of the present invention, in step (a), the amount of Zr added to the second dopant is 700~900ppm, for example, it can be any one value or a range of any two values ​​among 700ppm, 750ppm, 800ppm, 850ppm, and 900ppm; the amount of Al added is 1100~1300ppm, for example, it can be any one value or a range of any two values ​​among 1100ppm, 1150ppm, 1200ppm, 1250ppm, and 1300ppm; the amount of Y added is 300~500ppm, for example, it can be any one value or a range of any two values ​​among 300ppm, 350ppm, 400ppm, 450ppm, and 500ppm.

[0062] In some specific embodiments of the present invention, in step (a), the material mixing speed is 50~1000 rpm, the mixing time is 5~60 min, the mixing temperature is ≤50℃, and the mixing equipment includes, but is not limited to, high-speed mixer, plow mixer, batch mixer, etc.

[0063] In some specific embodiments of the present invention, in step (a), the first sintering is carried out in an oxygen-containing atmosphere (such as an air atmosphere or an oxygen atmosphere), and the temperature of the first sintering is 625~640°C, for example, it can be any one value or a range of any two values ​​among 625°C, 630°C, 635°C, and 640°C; the time of the first sintering is 7~18h, for example, it can be any one value or a range of any two values ​​among 7h, 10h, 15h, and 18h.

[0064] In some specific embodiments of the present invention, in step (b), the secondary sintering is carried out in an oxygen-containing atmosphere (such as an air atmosphere or an oxygen atmosphere), and the temperature of the secondary sintering is 600~790°C, for example, it can be any one value or a range of any two values ​​among 600°C, 650°C, 700°C, 755°C, and 790°C; the time of the secondary sintering is 20~30h, for example, it can be any one value or a range of any two values ​​among 20h, 22h, 25h, 28h, and 30h.

[0065] In some specific embodiments of the present invention, in step (b), the amount of Zr added to the second dopant is 2400~2600ppm, for example, it can be any one value or a range of any two values ​​among 2400ppm, 2450ppm, 2500ppm, 2550ppm, and 2600ppm; the amount of Al added is 600~800ppm, for example, it can be any one value or a range of any two values ​​among 600ppm, 650ppm, 700ppm, 750ppm, and 800ppm; the amount of Y added is 700~900ppm, for example, it can be any one value or a range of any two values ​​among 700ppm, 750ppm, 800ppm, 850ppm, and 900ppm.

[0066] In some specific embodiments of the present invention, in step (c), the second coating agent includes an aluminum coating agent and a boron coating agent; wherein the aluminum coating agent includes aluminum oxide and / or aluminum hydroxide; and / or, the boron coating agent includes boron oxide and / or boric acid.

[0067] In some specific embodiments of the present invention, in step (c), the three sinterings are carried out in an oxygen-containing atmosphere (such as an air atmosphere or an oxygen atmosphere), and the temperature of the three sinterings is 200~500°C, for example, it can be any one value or a range of any two values ​​among 200°C, 300°C, 400°C, and 500°C; the time of the three sinterings is 15~25h, for example, it can be any one value or a range of any two values ​​among 15h, 18h, 20h, 22h, and 25h.

[0068] In some specific embodiments of the present invention, in step S2, the mass ratio of the single-crystal ternary material to the polycrystalline ternary material is (1~10):(1~10). For example, it can be any one value or a range of any two values ​​from 1:10, 1:5, 1:3, 1:1, 3:1, 5:1, 10:1.

[0069] In some specific embodiments of the present invention, in step S2, the amount of high-entropy oxide accounts for 0.1% to 30% of the total mass of the single-crystal ternary material and the polycrystalline ternary material. For example, it can be any one value or a range of any two values ​​from 0.1%, 1%, 5%, 10%, 20%, and 30%. Too high or too low an amount will lead to a decrease in electrochemical performance.

[0070] In some specific embodiments of the present invention, in step S2, sintering is carried out in an oxygen-containing atmosphere (such as an air atmosphere or an oxygen atmosphere), and the sintering temperature is 100~600℃, for example, it can be any one value or a range of any two values ​​among 100℃, 200℃, 400℃, and 600℃; the sintering time is 1~24h, for example, it can be any one value or a range of any two values ​​among 1h, 6h, 12h, 18h, and 24h.

[0071] A third aspect of the present invention provides a lithium battery comprising the ternary cathode material described in any of the foregoing embodiments.

[0072] The following detailed description of some embodiments of the present invention is provided in conjunction with specific examples. Unless otherwise specified, all raw materials used in the embodiments are commercially available.

[0073] Example 1 Preparation of single-crystal ternary materials: (i) Weigh Ni 0.90 Co 0.06 Mn 0.04 The total amount of (OH)2 is 15000g, lithium hydroxide monohydrate is 7069.0g, zirconium oxide (zirconia) (first dopant) is 16.21g, aluminum oxide is 34.01g, and yttrium oxide is 7.62g. The mixture is mixed in a high-speed mixer at 150rpm for 5min and 400rpm for 20min, with the mixing temperature controlled at ≤40℃. After the material is evenly mixed, it is transferred to an atmosphere muffle furnace for sintering. The oxygen atmosphere concentration is ≥99.99%, the flow rate is 5L / min, the sintering temperature is 620℃, and the sintering cycle is 15h. The sintered material is crushed by roller crushing, demagnetized, and then prepared into the first pre-lithiation material. (ii) The first pre-lithiation material prepared in step (i) is mixed with 50.66 g of zirconium oxide, 19.84 g of alumina, and 15.24 g of yttrium oxide in a high-speed mixer at 150 rpm for 5 min and 400 rpm for 20 min, with the mixing temperature controlled at ≤40℃. After the material is mixed evenly, it is transferred to an atmosphere muffle furnace for sintering. The oxygen atmosphere concentration is ≥99.99%, the flow rate is 5 L / min, the sintering temperature is 835℃, and the sintering cycle is 26 h. After sintering, the material is coarsely crushed by roller crusher and then finely crushed by air jet mill to control the particle size D50 at 2.8 μm. After being demagnetized by sieve, it is prepared into the first semi-finished product. (iii) Take 10,000g of the first semi-finished product prepared in step (ii), 22.67g of the first coating agent alumina, 20.18g of tungsten oxide, and 43.63g of cobalt oxide, and mix them in a high-speed mixer at 150rpm for 5min and 400rpm for 20min, with the mixing temperature controlled ≤40℃. After the materials are evenly mixed, transfer them to an atmosphere muffle furnace for sintering. The oxygen atmosphere concentration is ≥99.99%, the flow rate is 5L / min, the sintering temperature is 695℃, and the sintering cycle is 19h. After sintering, the material is crushed by roller crushing, sieved, and demagnetized to prepare a coated modified gradient-doped single-crystal ternary material. Its SEM image is shown below. Figure 4 As shown.

[0074] Preparation of polycrystalline ternary materials: (a) Weighing Ni 0.90 Co 0.06 Mn 0.04 The total amount of (OH)2 is 15000g, lithium hydroxide monohydrate is 7069.0g, zirconium oxide (zirconia) (the second dopant) is 16.21g, aluminum oxide is 34.01g, and yttrium oxide is 7.62g. The mixture is mixed in a high-speed mixer at 150rpm for 5min and 400rpm for 20min, with the mixing temperature controlled at ≤40℃. After the material is evenly mixed, it is transferred to an atmosphere muffle furnace for sintering. The oxygen atmosphere concentration is ≥99.99%, the flow rate is 5L / min, the sintering temperature is 630℃, and the sintering cycle is 15h. The sintered material is crushed by roller crushing, demagnetized, and then prepared into the second pre-lithiation material. (b) The second pre-lithiation material prepared in step (a) is mixed with 50.66 g of the second dopant zirconium oxide, 19.84 g of alumina, and 15.24 g of yttrium oxide in a high-speed mixer at 150 rpm for 5 min and 400 rpm for 20 min, with the mixing temperature controlled at ≤40℃. After the material is mixed evenly, it is transferred to an atmosphere muffle furnace for sintering. The oxygen atmosphere concentration is ≥99.99%, the flow rate is 5 L / min, the sintering temperature is 755℃, and the sintering cycle is 22 h. After sintering, the material is coarsely crushed by roller crusher, and then finely crushed by air jet mill to control the particle size D50 at 8.5 μm. After sieving and demagnetizing, it is washed and dried to prepare the second semi-finished product. (c) Take 10,000 g of the second semi-finished product prepared in step (b), 22.67 g of the second coating agent alumina, and 22.54 g of boron oxide, and mix them in a high-speed mixer at 150 rpm for 5 min and 400 rpm for 20 min, with the mixing temperature controlled ≤40℃. After the materials are evenly mixed, transfer them to an atmosphere muffle furnace for sintering. The oxygen atmosphere concentration is ≥99.99%, the flow rate is 5 L / min, the sintering temperature is 320℃, and the sintering cycle is 18 h. After sintering, the material is crushed by roller crushing, sieved, and demagnetized to prepare a coated modified gradient-doped polycrystalline ternary material. Its SEM image is shown below. Figure 5 As shown.

[0075] Preparation of high-entropy oxides: The molecular formula of the high-entropy oxide is Li 0.23 V 0.11 Ti 0.21 Al 0.15 Co 0.19 Zr 0.11 O 1.55 Weigh out 205.6g of vanadium pentoxide, 344.9g of titanium dioxide, 157.2g of aluminum oxide, 278.6g of zirconium oxide, 323.9g of cobalt trioxide, and 174.7g of lithium carbonate. After mixing thoroughly, add 3.8kg of deionized water and disperse evenly. Then, perform sand milling using 0.15mm zirconium balls with a zirconium ball filling rate of 75%. The milling speed is 2800rpm, and the milling time is 2h. After 2h, take a sample of the slurry to test the particle size. The particle size D50 is 0.25μm. After sand milling, the spray drying is set with an inlet air temperature of 220℃, an outlet air temperature of 109℃, and a centrifugal atomizer speed of 340Hz. The powder after spraying is transferred to a sagger and sintered in a box-type atmosphere furnace at a temperature of 1100℃ for 13 hours. The sintering atmosphere is an oxygen atmosphere with an oxygen flow rate of 5L / min. After sintering, the powder is crushed, and the particle size D50 of the crushed powder is about 1μm.

[0076] Preparation of ternary cathode materials: 2500g of single-crystal ternary material, 7500g of polycrystalline ternary material, and 405.0g of high-entropy oxide prepared in this embodiment were weighed and mixed at 120rpm for 5min and then at 350rpm for 20min in a high-speed mixer. The mixing temperature was controlled to be ≤40℃. After uniform mixing, the mixture was transferred to an atmosphere muffle furnace for sintering at 255℃ for 16h. The sintering atmosphere was oxygen atmosphere with an oxygen concentration >99.9%. After sintering, the mixture was coarsely crushed by roller crushing, sieved, and demagnetized to prepare ternary cathode material. Its SEM image is shown below. Figure 6 As shown.

[0077] Example 2 Example 2 is similar to Example 1, except that the amount of high-entropy oxide used in the preparation of the ternary cathode material is 250g, and all other conditions are the same as in Example 1.

[0078] Example 3 Example 3 is similar to Example 1, except that the amount of high-entropy oxide used in the preparation of the ternary cathode material is 530g, and all other conditions are the same as in Example 1.

[0079] Example 4 Example 4 is similar to Example 1, except that when preparing the ternary cathode material, the amount of single-crystal ternary material is 1000g and the amount of polycrystalline ternary material is 10000g. All other conditions are the same as in Example 1.

[0080] Example 5 Example 5 is similar to Example 1, except that when preparing the ternary cathode material, the amount of single-crystal ternary material is 10,000g and the amount of polycrystalline ternary material is 1,000g. All other conditions are the same as in Example 1.

[0081] Comparative Example 1 Comparative Example 1 is similar to Example 1, except that no high-entropy oxide was added when preparing the ternary cathode material, and all other conditions were the same as in Example 1.

[0082] Comparative Example 2 Comparative Example 2 is similar to Example 1, except that when preparing the ternary cathode material, the polycrystalline ternary material is replaced with an equal amount of monocrystalline ternary material, that is, the monocrystalline ternary material and the polycrystalline ternary material are not mixed, and only the surface of the monocrystalline ternary material is coated with a high-entropy oxide; all other conditions are the same as in Example 1.

[0083] Comparative Example 3 Comparative Example 3 is similar to Example 1, except that: when preparing the ternary cathode material, the single-crystal ternary material is replaced with an equal amount of polycrystalline ternary material, that is, the single-crystal ternary material and polycrystalline ternary material are not mixed, and only the polycrystalline ternary material is coated with a high-entropy oxide; all other conditions are the same as in Example 1.

[0084] Comparative Example 4 Comparative Example 4 is similar to Example 1, except that neither the single-crystal ternary material nor the polycrystalline ternary material was subjected to bulk doping or surface coating, and no high-entropy oxide was added for coating when preparing the cathode material by mixing; all other conditions are the same as in Example 1.

[0085] Test case 1. The compaction density of the ternary cathode materials prepared in each embodiment and comparative example was tested; and coin cells were assembled using the ternary cathode materials prepared in each embodiment and comparative example. The coin cells used were of the CR2032 type. The mass ratio of the positive electrode active material to the binder and conductive agent was 8:1:1. The ambient temperature during the homogenization process was ≤25℃, and the humidity was ≤5%. Lithium metal sheets were used as the negative electrode. The assembly of the coin cells was carried out in a glove box under an argon atmosphere. The discharge specific capacity at 0.1C, 1C, 2C, and 3C, as well as the first-cycle efficiency at 0.1C, were tested. The test voltage was 3.0~4.3V. The test results are shown in Table 1. The charge-discharge curve of the half-cell assembled with the ternary cathode material in Example 1 at 0.1C is shown in Table 1. Figure 7 The compaction density was tested under the following conditions: a pressure of 350 MPa, a pressure increment of 10 MPa, a holding time of about 10 seconds, an ambient temperature of ≤25℃, and a humidity of ≤5%. The test results are shown in Table 1.

[0086] Table 1

[0087] As shown in Table 1, the ternary cathode material prepared in the embodiments of the present invention not only has a high compaction density, but also exhibits significantly better electrochemical performance than the comparative example; among them, Example 1 shows the best performance. In the present invention, the gradient doping design stabilizes the structural stability of the material after delithiation, and the high-temperature coating design of single-crystal and polycrystalline ternary materials consumes the residual lithium hydroxide in the reaction process, suppressing the side reactions between the electrolyte and the ternary material; the mixed coating of single-crystal and polycrystalline particles with high-entropy oxides improves both compaction density and rate performance.

[0088] 2. Full battery cycle performance test The battery cell has a designed capacity of 24Ah under 0.33C charge / discharge conditions. The positive electrode portion has a positive electrode material to SP, CNT, and binder (PVDF) ratio of 96.5%:2%:0.5%:1%. The aluminum foil thickness is 13μm, and the coating density on one side is 180g / m². 2 The compacted density is 3.35 g / cm³. 3 The positive electrode consists of 14 sheets. For the negative electrode: the ratio of graphite to CMC and SBR is 97%:1.2%:1.8%, the copper foil thickness is 6μm, and the coating density on one side is 120g / m². 2 The compacted density is 1.56 g / cm³. 3 The negative electrode consists of 15 sheets. The N / P ratio at 0.1C initial charge is 1.06 for both positive and negative electrodes, and at 0.1C discharge after formation, the N / P ratio is 1.1. A commercially available high-nickel ternary electrolyte is used. The separator is 13μm thick, made of PE, and has a porosity of 40%–45%. The fabrication process is consistent with commercial soft-pack processes, using a stacking assembly method. The full-cycle testing conditions are 45℃, voltage 2.75–4.3V, and charge / discharge current of 1C.

[0089] The cyclic stability test results of Example 1 and Comparative Example 4 are as follows: Figure 8 As shown, the cycle performance of the full cell assembled with the ternary cathode material prepared in Example 1 is significantly better than that of Comparative Example 4.

[0090] Compared to the comparative example, the embodiments of the present invention have significant advantages in cycling performance. This is mainly attributed to the gradient doping and double-layer coating design. The gradient doping of Al, Zr, and Y effectively stabilizes the structural stability of the ternary material after lithium removal. 4+ Lower Li + / Ni 2+ Mixed arrangement, with some Zr entering the lithium layer to act as a support; Al 3+ Stabilizes oxygen in the material, inhibiting oxygen evolution; Y 3+Doping effectively suppresses harmful phase transitions in ternary materials during charge and discharge: it enhances the coupling between the Li layer and the transition metal (TM) layer, delays the H1-H3 phase transition under high voltage, and reduces microcrack formation. The surface of polycrystalline particles is coated with boron oxide and aluminum oxide to form a dense and uniform inorganic protective layer, effectively isolating the cathode material from direct contact with the electrolyte, thereby significantly reducing side reactions such as oxidation and decomposition of the electrolyte on the cathode material surface during charge and discharge. In single-crystal particles, W in tungsten oxide... 6+ Ion coatings introduced into the surface of ternary materials can increase the material's electronic conductivity. Furthermore, the nanoscale tungsten oxide coating constructs a highly efficient conductive network on the material surface. Alumina, with its stable chemical inertness and high mechanical strength, forms a robust physical barrier against electrolyte corrosion and alleviates structural strain. Cobalt oxide coating consumes Li₂CO₃ / LiOH on the material surface, reducing surface alkalinity, and also acts as a protective layer to slow the dissolution of metal ions such as Mn and Ni in the electrolyte. High-entropy additives coated on the surface of ternary materials induce lithium-ion migration, significantly promoting lithium-ion migration at the interface, reducing ion transport resistance, and thus improving rate performance.

[0091] Although the present invention has been illustrated and described with specific embodiments, it should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; those skilled in the art should understand that modifications can be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein, without departing from the spirit and scope of the present invention; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention; therefore, this means that all such substitutions and modifications that fall within the scope of the present invention are included in the appended claims.

Claims

1. A ternary cathode material, characterized in that, include: First particle and second particle; The first particle has a single crystal structure, and the bulk phase of the first particle is doped with a first doping element, and its surface is sequentially coated with a first coating layer and a high-entropy oxide coating layer. The second particle has a polycrystalline structure; the bulk phase of the second particle is doped with a second doping element, and its surface is sequentially coated with a second coating layer and a high-entropy oxide coating layer. The first particle and the second particle each independently have the chemical formula Li. x Ni a Co b Mn 1-a-b O2, where 1.0≤x≤1.1, 0<a<1, 0<b<1, a+b<1.

2. The ternary cathode material according to claim 1, characterized in that, It meets at least one of the following characteristics: (1) The first doping element includes Al, Zr and Y; (2) The first dopant element is distributed in a gradient within the first particle; (3) The first doping element includes Al, Zr and Y, wherein the contents of Al, Zr and Y in the first particle are independently controlled at 100~10000ppm; (4) The first coating layer comprises oxides of Al, W and Co; (5) The first coating layer includes oxides of Al, W and Co, wherein the contents of Al and W in the first particle are 100~20000ppm and the contents of Co in the first particle are 100~50000ppm respectively; (6) The second doping element includes Al, Zr and Y; (7) The second dopant element is gradient-distributed in the second particle; (8) The second doping element includes Al, Zr and Y, wherein the contents of Al, Zr and Y in the second particle are independently controlled at 100~10000ppm; (9) The second coating layer comprises oxides of both Al and B; (10) The second coating layer comprises oxides of both Al and B, wherein the contents of Al and B in the second particles are independently 100 to 20000 ppm; (11) The mass ratio of the first particle to the second particle is (1~10):(1~10); (12) The high-entropy oxide accounts for 0.1% to 30% of the total mass of the first particle and the second particle; (13) The general formula of the high-entropy oxide is Li a V b Ti c Al d Co e Zr f O x , where 0 < a, b, c, d, e, f < 0.25, 0 < x < 3.

3. The ternary cathode material according to claim 1 or 2, characterized in that, The method for preparing the high-entropy oxide includes: mixing a vanadium source, a titanium source, an aluminum source, a cobalt source, a zirconium source, a lithium source, and a solvent, followed by sand milling, spray drying, sintering, and crushing.

4. The ternary cathode material according to claim 3, characterized in that, The method for preparing the high-entropy oxide satisfies at least one of the following characteristics: (1) The vanadium source includes vanadium pentoxide and / or vanadate; (2) The titanium source includes at least one of titanium oxide, titanium chloride, and titanium sulfate; (3) The aluminum source includes aluminum oxide and / or aluminum hydroxide; (4) The cobalt source includes cobalt oxide and / or cobalt nitrate; (5) The zirconium source includes at least one of zirconium oxide, zirconium sulfate, and zirconium chloride; (6) The lithium source includes at least one of lithium carbonate, lithium hydroxide, and lithium oxalate; (7) After sand milling, the particle size D50 of the slurry is 0.2~0.35μm; (8) The inlet air temperature of the spray dryer is 180~230℃ and the outlet air temperature is 105~110℃; (9) The sintering is carried out in an oxygen-containing atmosphere; the sintering temperature is 600~1200℃, preferably 1100~1200℃; the sintering time is 12~16h; (10) The particle size D50 after crushing is 0.8~1.5μm.

5. The method for preparing the ternary cathode material according to any one of claims 1 to 4, characterized in that, Includes the following steps: S1. Prepare a first particle, dope it with a first doping element in its bulk phase, and coat it with a first coating layer to obtain a single-crystal ternary material; A second particle is prepared, and a second doping element is doped into its bulk phase. A second coating layer is then coated on its surface to obtain a polycrystalline ternary material. S2. The single-crystal ternary material, the polycrystalline ternary material and the high-entropy oxide are mixed and sintered, and then crushed, sieved and demagnetized to obtain the ternary cathode material.

6. The method for preparing the ternary cathode material according to claim 5, characterized in that, In step S1, the preparation method of the single-crystal ternary material includes: (i) A nickel-cobalt-manganese compound is mixed with a lithium salt and a portion of the first dopant, and then sintered once to obtain the first pre-lithiation material; (ii) The first pre-lithiation material is mixed with the remaining first dopant, and then sintered twice. After crushing and sieving to remove magnetism, the first semi-finished product is obtained. (iii) The first semi-finished product is mixed with the first coating agent and sintered three times. After crushing, sieving and demagnetizing, the single crystal ternary material is obtained. And / or, the method for preparing the polycrystalline ternary material includes: (a) A nickel-cobalt-manganese compound is mixed with a lithium salt and a portion of a second dopant, and then sintered once to obtain a second pre-lithiation material; (b) The second pre-lithiation material is mixed with the remaining second dopant, sintered twice, crushed, sieved and demagnetized to obtain the second semi-finished product; (c) The second semi-finished product is washed and dried, then mixed with the second coating agent, sintered three times, crushed, sieved and demagnetized to obtain the polycrystalline ternary material.

7. The method for preparing the ternary cathode material according to claim 6, characterized in that, During the preparation of the single-crystal ternary material, at least one of the following characteristics is satisfied: (1) The nickel-cobalt-manganese compound includes nickel-cobalt-manganese oxide and / or nickel-cobalt-manganese hydroxide; (2) The lithium salt includes at least one of lithium carbonate, lithium hydroxide, and lithium acetate; (3) The first dopant includes a zirconium dopant, an aluminum dopant and a yttrium dopant; wherein the zirconium dopant includes at least one of zirconium oxide, zirconium carbonate, zirconium nitrate and zirconium sulfate; and / or the aluminum dopant includes aluminum oxide and / or aluminum hydroxide; and / or the yttrium dopant includes at least one of yttrium oxide, yttrium chloride and yttrium fluoride; (4) The first sintering is carried out in an oxygen-containing atmosphere, and the temperature of the first sintering is 600~630℃ and the time is 7~18h; (5) The secondary sintering is carried out in an oxygen-containing atmosphere, and the temperature of the secondary sintering is 800~900℃ and the time is 20~30h; (6) The first coating agent includes an aluminum coating agent, a tungsten coating agent and a cobalt coating agent; wherein the aluminum coating agent includes aluminum oxide and / or aluminum hydroxide; and / or the tungsten coating agent includes tungsten oxide and / or tungstic acid; and / or the cobalt coating agent includes at least one of cobalt oxide, cobalt tetroxide, cobalt carbonate and cobalt hydroxide; (7) The three sinterings are carried out in an oxygen-containing atmosphere, and the temperature of the three sinterings is 600~800℃ and the time is 15~25h.

8. The method for preparing the ternary cathode material according to claim 6, characterized in that, During the preparation of the polycrystalline ternary material, at least one of the following characteristics is satisfied: (1) The nickel-cobalt-manganese compound includes nickel-cobalt-manganese oxide and / or nickel-cobalt-manganese hydroxide; (2) The lithium salt includes at least one of lithium carbonate, lithium hydroxide, and lithium acetate; (3) The second dopant includes a zirconium dopant, an aluminum dopant, and a yttrium dopant; wherein the zirconium dopant includes at least one of zirconium oxide, zirconium carbonate, zirconium nitrate, and zirconium sulfate; and / or the aluminum dopant includes aluminum oxide and / or aluminum hydroxide; and / or the yttrium dopant includes at least one of yttrium oxide, yttrium chloride, and yttrium fluoride; (4) The first sintering is carried out in an oxygen-containing atmosphere, and the temperature of the first sintering is 625~640℃ and the time is 7~18h; (5) The secondary sintering is carried out in an oxygen-containing atmosphere, and the temperature of the secondary sintering is 600~790℃ and the time is 20~30h; (6) The second coating agent includes an aluminum coating agent and a boron coating agent; wherein the aluminum coating agent includes aluminum oxide and / or aluminum hydroxide; and / or the boron coating agent includes boron oxide and / or boric acid; (7) The three sinterings are carried out in an oxygen-containing atmosphere, and the temperature of the three sinterings is 200~500℃ and the time is 15~25h.

9. The method for preparing the ternary cathode material according to any one of claims 5 to 8, characterized in that, In step S2, at least one of the following characteristics is satisfied: (1) The mass ratio of the single-crystal ternary material to the polycrystalline ternary material is (1~10):(1~10); (2) The amount of the high-entropy oxide accounts for 0.1% to 30% of the total mass of the single-crystal ternary material and the polycrystalline ternary material; (3) The sintering is carried out in an oxygen-containing atmosphere, the sintering temperature is 100~600℃, and the time is 1~24h.

10. A lithium battery, characterized in that, Includes the ternary cathode material as described in any one of claims 1 to 4.

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