Positive electrode material for all-solid-state lithium-ion batteries, manufacturing method, and application thereof

Abstract

To provide a positive electrode material, a manufacturing method for the same, and an application thereof, capable of improving the interface stability between a positive electrode sheet and a solid electrolyte and enhancing the stability and cycle performance of a lithium ion battery.SOLUTION: The present invention provides a positive electrode material, a manufacturing method for the same, and an application thereof. The positive electrode material includes at least a positive electrode active material, and a coating layer coating the positive electrode active material and containing a halide solid electrolyte. The positive electrode active material includes nLi2MnO3 / (1-n)LiMnaCobNicO2, in which 0.2≤n≤0.5 and a+b+c=1 are satisfied. The chemical formula of the halide solid electrolyte is Li2+mZr1-mFemCl6-x-yBrxIy, in which 0<m≤0.5, x=0 to 6, y=0 to 6, and x+y≤6 are satisfied.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to the technical field of lithium ion batteries, and in particular to positive electrode materials and manufacturing methods and applications thereof. [Background technology]

[0002] With the development of secondary batteries, particularly lithium-ion batteries, lithium-ion batteries have become widely used in portable electronic devices and electric vehicles. However, in recent years, conventional lithium-ion batteries have frequently experienced safety accidents due to the use of flammable organic solvents as electrolytes, posing serious safety risks. This issue cannot be completely resolved by conventional improvement methods. In contrast, all-solid-state lithium-ion batteries using inorganic solid electrolytes offer greater safety. Among existing inorganic solid electrolytes, sulfide solid electrolytes are expected to be used in applications due to their advantages, such as high lithium-ion conductivity, low interfacial resistance, and Young's modulus. However, the stability of the interface between high-voltage positive electrode materials and sulfide solid electrolytes leads to poor cycle performance of the positive electrode. This issue can be alleviated by modifying the surface of high-voltage lithium-rich manganese-based positive electrode materials with a stable oxide coating, but this requires specialized equipment and high costs. Summary of the Invention [Problem to be solved by the invention]

[0003] The present invention provides a positive electrode material, a manufacturing method thereof, and applications thereof, which can significantly reduce costs and effectively inhibit side reactions between the positive electrode material and the sulfide electrolyte under high voltage, improving the interfacial stability between the electrode and the solid electrolyte, thereby improving the stability and cycle performance of the battery. [Means for solving the problem]

[0004] In order to solve the above technical problems, the present invention is realized through the following technical solutions.

[0005] The present invention provides a cathode material comprising at least: a positive electrode active material; A coating layer that coats the positive electrode active material and contains a halide solid electrolyte. Here, the positive electrode active material is nLi2MnO3·(1-n)LiMn a Co b Ni c O2, 0.2≦n≦0.5, a+b+c=1, and the chemical formula of the halide solid electrolyte is Li 2+m Zr 1-m Fe m Cl 6-x-y Br x I y and 0 <m≦0.5、x=0~6、y=0~6、x+y≦6である。

[0006] In one embodiment of the present invention, the molar ratio of iron atoms on the surface of the positive electrode material measured with an energy dispersive X-ray analyzer is 0.4% to 7%.

[0007] In one embodiment of the present invention, the chemical formula of the halide solid electrolyte is Li 2.3 Zr 0.7 Fe 0.3 It is Cl6.

[0008] In one embodiment of the present invention, the positive electrode active material is spherical.

[0009] In one embodiment of the present invention, the median diameter D50 of the spherical positive electrode active material is 8 μm to 20 μm.

[0010] The present invention also provides a method for producing a positive electrode material, which includes at least the following steps: Mixing compounds containing Li, Zr, and Fe elements in corresponding amounts, and then grinding and primary sintering to obtain a halide solid electrolyte according to the chemical formula of the halide solid electrolyte; The halide solid electrolyte and the positive electrode active material are mixed according to a mass ratio and then subjected to secondary baking to obtain a positive electrode material.

[0011] In one embodiment of the present invention, the mass ratio of the halide solid electrolyte to the positive electrode active material is (0.2 to 6):(99.9 to 94).

[0012] In one embodiment of the present invention, the mixing conditions include a mixing speed of 100 rpm to 800 rpm and a mixing time of 1 hour to 6 hours.

[0013] In one embodiment of the present invention, the secondary firing temperature is 950°C to 1050°C, and the sintering time is 6 hours to 18 hours.

[0014] The present invention also provides a lithium ion battery containing the above-mentioned positive electrode material or the positive electrode material obtained by the above-mentioned production method.

[0015] The present invention also provides an electronic device including the lithium ion battery. [Effects of the Invention]

[0016] Based on the above, the present invention provides a cathode material and manufacturing method for obtaining a halide solid electrolyte with low cost, high ionic conductivity, and high voltage resistance, as well as its application, thereby solving the problem of interfacial instability between a high-voltage lithium-excess manganese-based cathode material and a sulfide solid electrolyte. The halide solid electrolyte has high compatibility with the high-voltage lithium-excess manganese-based cathode material, improving the lithium ion conductivity of the cathode material and effectively improving the ion transfer dynamics of the cathode material, thereby improving the rate performance of the battery. This effectively suppresses side reactions between the cathode material and the sulfide electrolyte at high voltages, improving the interfacial stability between the electrode and the solid electrolyte, thereby improving the stability and cycle performance of the battery. By improving the reversible oxidation-reduction ability of oxygen during cycling, the dissolution of transition metals and the release of oxygen from the cathode are suppressed, thereby improving the initial coulombic efficiency and cycle life. [Brief explanation of the drawings]

[0017] In order to more clearly describe the technical solutions in the embodiments of the present invention, the following briefly introduces the figures necessary for describing the embodiments. Obviously, the figures in the following description are only some embodiments of the present invention, and those skilled in the art can obtain other figures based on these figures without requiring creativity. [Figure 1] 1 is a flowchart of a method for producing a positive electrode material according to the present invention. [Figure 2] 1 is a scanning electron microscope photograph of a positive electrode material in Example 1 of the present invention. [Figure 3] FIG. 2 is an EDS spectrum diagram of the positive electrode material in Example 1 of the present invention. [Figure 4] 1 is a scanning electron microscope photograph of a positive electrode material in Comparative Example 1 of the present invention. [Figure 5] FIG. 2 is an EDS spectrum diagram of a positive electrode material in Comparative Example 1 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, the present invention will be described with reference to specific examples, and those skilled in the art will easily understand other advantages and effects of the present invention from the disclosure of this specification. The present invention may be implemented or applied through other different specific embodiments, and various modifications or changes can be made to the details of this specification based on different perspectives and applications without departing from the spirit of the present invention.

[0019] It is understood that the present invention can be embodied in different forms and should not be construed as limited to the examples set forth herein. Rather, these examples are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the following examples, "%" and "parts" mean "% by weight" and "parts by weight," respectively, unless otherwise specified.

[0020] The technical solution of the present invention will be further described in detail below with reference to some embodiments and drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. Based on one embodiment of the present invention, all other embodiments can be obtained by those skilled in the art without creative efforts and are included within the scope of the present invention.

[0021] The present invention provides a positive electrode material including a positive electrode active material and a coating layer covering the positive electrode active material. Here, the positive electrode active material is a high-voltage positive electrode active material, and the high-voltage positive electrode active material is, for example, a lithium-excess manganese-based positive electrode material, and further, nLi2MnO3·(1-n)LiMn a Co b Ni c O2, where 0.2≦n≦0.5 and a + b + c = 1. The coating layer contains a halide solid electrolyte, and the chemical formula of the halide solid electrolyte is, for example, Li 2+m Zr 1-m Fe m Cl 6-x-y Br x I y where 0 < m≦0.5, x = 0 to 6, y = 0 to 6, and x + y≦6. In one embodiment of the present invention, the halide solid electrolyte is, for example, Li 2.3 Zr 0.7 Fe 0.3 Cl6. In the present invention, the halide solid electrolyte does not contain rare earth metals. Therefore, the cost can be significantly reduced, and the halide solid electrolyte uses iron as a doping element, thereby further reducing the cost, and Fe in the crystal lattice 3+The substitution of Fe improves the ionic conductivity of the halide solid electrolyte. The Fe element has a stronger bonding ability with the O element in the lithium-excess manganese-based positive electrode material, which is beneficial for improving the reversible redox ability of the O element during cycling. This reduces the dissolution of the transition metal and the release of oxygen from the positive electrode, improving the initial coulombic efficiency and cycle life. The halide solid electrolyte, when coated on the high-voltage lithium-excess manganese-based positive electrode material, effectively suppresses side reactions between the positive electrode active material and the sulfide electrolyte at high voltages, improving the interfacial stability between the electrode and the solid electrolyte, thereby improving the stability and cycle performance of the battery.

[0022] In one embodiment of the present invention, the positive electrode active material is, for example, spherical, and the median diameter D50 of the spherical positive electrode active material is 8 μm to 20 μm. The median diameter of the positive electrode active material is controlled to prevent a decrease in processability due to an excessively small particle size, and to prevent a decrease in electrochemical performance due to an excessively large particle size, while also improving the processability and electrochemical performance of the positive electrode active material.

[0023] In one embodiment of the present invention, the cathode material is a cathode active material in which a halide solid electrolyte is uniformly coated on the surface thereof, and the distribution of iron atoms on the surface of the cathode material is measured using an energy dispersive X-ray analyzer (EDS) to determine the amount of the halide solid electrolyte applied and the uniformity of the application. In this embodiment, the molar ratio of iron atoms on the surface of the cathode material is, for example, 0.4% to 7%. That is, the halide solid electrolyte is a high-voltage lithium-excess manganese-based cathode material nLi2MnO3·(1-n)LiMn a Co b Ni c It has good compatibility with O2. At the same time, by coating the surface of the positive electrode active material with a halide solid electrolyte with high ion conductivity, the ion transport dynamics can be effectively improved, thereby improving the rate performance of the battery.

[0024] 1, the present invention also provides a method for producing a positive electrode active material, which includes, but is not limited to, steps S100 to S200.

[0025] Step S100: According to the chemical formula of the halide solid electrolyte, compounds containing Li, Zr, and Fe are mixed in corresponding amounts, and then polished and primarily sintered to obtain the halide solid electrolyte.

[0026] Step S200: A halide solid electrolyte and a positive electrode active material are mixed according to a mass ratio, and then subjected to secondary baking to obtain a positive electrode material.

[0027] Referring to FIG. 1, in one embodiment of the present invention, in step S100, a halide solid electrolyte Li 2+a Zr 1-a Fe a Cl (6-x-y) Br x I y According to the chemical formula, compounds containing Li, Zr, and Fe ions in corresponding molar amounts are mixed to form a mixture, and then the mixture is polished and primary sintered to obtain a halide solid electrolyte. In one embodiment of the present invention, the chemical formula of the halide solid electrolyte is, for example, Li 2.3 Zr 0.7 Fe 0.3 The raw materials are selected from, for example, lithium chloride (LiCl), zirconium chloride (ZrCl4), and ferric chloride (FeCl3). In this embodiment, in order to mix and contact the raw materials more uniformly, the raw materials are mixed, for example, by a ball mill. The rotation speed of the ball mill is, for example, 400 rpm to 700 rpm, or 500 rpm. The mixing time in the ball mill is, for example, 1.5 hours to 3 hours, or 2 hours. The diameter of the ball-milled zirconium beads is, for example, 8 mm to 15 mm, or 10 mm. The ratio of balls to materials is, for example, (20:30:1), or 30:1.

[0028] See FIG. 1. In one embodiment of the present invention, after obtaining the mixture in step S100, the mixture can be processed by, for example, ball milling, solid-phase sintering, or thermal eutectic method, or the mixture can be prepared by polishing and sintering. Here, the polishing speed is, for example, 900 rpm, 1200 rpm, or 1000 rpm. The rotation speed is, for example, 8 to 15 hours or 10 hours. The polishing time is, for example, 8 to 15 hours or 10 hours. The polished mixture is subjected to a primary sintering process to obtain a halide solid electrolyte. Specifically, the sintering temperature rise rate is, for example, 4°C / min to 5°C / min, the primary sintering temperature is, for example, 250°C to 350°C, the sintering time is, for example, 3 to 5 hours, the sintering atmosphere is, for example, an inert gas, and the sintering time is the time from when the temperature is raised to the primary sintering temperature. The primary sintering can enhance the crystallinity of the halide solid electrolyte. After sintering is completed, the halide solid electrolyte is cooled by furnace cooling. In the halide solid electrolyte of the present invention, Fe element is used as a doping element, and Fe in the crystal lattice 3+ The equivalent substitution of improves the ionic conductivity of the electrolyte. In one embodiment of the present invention, the ionic conductivity of the halide solid electrolyte is ≧1 mS / cm.

[0029] See FIG. 1. In one embodiment of the present invention, in step S200, after obtaining a halide solid electrolyte, the halide solid electrolyte and the positive electrode active material are mixed according to a mass ratio. In this embodiment, the mass ratio of the halide solid electrolyte to the positive electrode active material is (0.2 to 6):(99.99 to 94), for example, 0.8:99.8, 1:99, 2:98, 3:97, 4:96, or 5:95. In the mixing step, the rotation speed of the mixer is, for example, 100 rpm to 800 rpm, the mixing time is, for example, 1 hour to 6 hours, and the ball-to-material ratio is, for example, 20:1. Next, the mixed halide solid electrolyte and positive electrode active material are subjected to secondary firing. Here, the temperature rise rate for sintering is, for example, 8°C / min to 10°C / min, the temperature for secondary firing is, for example, 950°C to 1050°C, the sintering time is, for example, 6 hours to 18 hours, the sintering atmosphere is, for example, an inert gas, and the sintering time is the time from when the temperature is raised to the secondary firing temperature. In this embodiment, the positive electrode active material is, for example, nLi2MnO3·(1-n)LiMn a Co b Ni c The materials used are O2, where 0.2≦n≦0.5 and a+b+c=1, and the positive electrode active material is spherical. Energy-dispersive X-ray spectroscopy (EDX) analysis of the resulting positive electrode material revealed that the molar ratio of Fe atoms on the surface was 0.4% to 7%. Secondary sintering not only forms a good ion-permeable interface between the halide solid electrolyte and the lithium-excess manganese-based positive electrode material, but also improves the density of the halide solid electrolyte, helping to produce high-quality positive electrode materials.

[0030] The present invention also provides a lithium-ion battery including a positive electrode sheet, a solid electrolyte, and a negative electrode sheet. The solid electrolyte is disposed between the positive electrode sheet and the negative electrode sheet. The solid electrolyte can be obtained, for example, by pressing a fast-ion conductor into a tablet, maintaining a pressure of 0.8 to 1.5 tons for 3 to 8 minutes. In other embodiments, other preparation methods can be used to obtain the solid electrolyte. In this embodiment, the fast-ion conductor can be, for example, a sulfide fast-ion conductor, such as Li6PS5Cl. The positive electrode sheet includes a positive electrode material, a fast-ion conductor, a conductive agent, and the like. The positive electrode material is a positive electrode material coated with a halide solid electrolyte, and the fast-ion conductor can be the same as or different from the fast-ion conductor in the solid electrolyte. In this embodiment, the fast ion conductor in the positive electrode sheet is, for example, Li6PS5Cl, and the conductive agent is, for example, conductive carbon black (Super P, SP), carbon nanotubes (CNT), carbon fiber (VGCF), graphene, silver powder, aluminum powder, etc. In one embodiment of the present invention, the mass ratio of the positive electrode material, fast ion conductor, and conductive agent is, for example, (65-89):(10-30):(1-5). The positive electrode material, fast ion conductor, and conductive agent are ground in a mortar for 15 to 30 minutes and uniformly mixed to obtain a composite positive electrode powder. This composite positive electrode powder is pressed onto the solid electrolyte and held under a pressure of 0.8 to 1.5 tons for 3 to 8 minutes to obtain a positive electrode sheet. The negative electrode sheet is, for example, a metallic lithium sheet. This metallic lithium sheet is pressed from the solid electrolyte side opposite the positive electrode sheet and held under a pressure of, for example, 0.1 to 0.2 tons to obtain an all-solid-state lithium-ion battery. Here, the assembly process of the all-solid-state lithium-ion battery is completed in an argon atmosphere glove box.

[0031] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Appropriate modifications are possible within the scope of the present invention, and all such modifications fall within the technical scope of the present invention.

[0032] Example 1

[0033] Li 2.3 Zr 0.7 Fe 0.3 Cl6 and 0.5Li2MnO3·0.5LiMn 1 / 3 Co 1 / 3 Ni 1 / 3 O2 was placed in a ball mill and mixed at a mass ratio of 3:97. The mixing speed was 600 rpm, the mixing time was 3 hours, and the ball milling ratio was 20:1. The mixed powder was then placed in a muffle furnace and sintered at a heating rate of 10°C / min, a sintering temperature of 1000°C, a sintering time of 12 hours, and an argon atmosphere. After sintering, the mixture was polished and sieved to obtain a high-voltage lithium-excess manganese-based positive electrode material coated with a halide solid electrolyte. Energy-dispersive X-ray spectroscopy (EDX) analysis revealed that the molar ratio of Fe atoms on the surface of the positive electrode material was 2.8%.

[0034] 50 mg of Li6PS5Cl was taken out and placed in a mold. It was then pressed into the solid electrolyte under 1 ton of pressure for 5 minutes. The coated cathode material, Li6PS5Cl, and conductive carbon black were weighed in a 70:29:1 mass ratio, added to a mortar, and hand-ground for 20 minutes to obtain a composite cathode powder. Next, 10 mg of the composite cathode powder was placed on the solid electrolyte and held under 1 ton of pressure for 5 minutes to form a cathode sheet. After removal, the solid electrolyte was turned over, and a metallic lithium piece was placed on the solid electrolyte side of the cathode sheet. The metallic lithium piece had a diameter of 10 mm. This was then pressurized to 0.1 ton and maintained to obtain an all-solid-state lithium-ion battery. The assembly process for the all-solid-state lithium-ion battery was completed in an argon-atmosphere glove box.

[0035] Example 2

[0036] Li 2.3 Zr 0.7 Fe 0.3 Cl6 and 0.5Li2MnO3·0.5LiMn 1 / 3 Co 1 / 3 Ni 1 / 3The mass ratio of O2 was 6:94. The molar ratio of Fe atoms on the surface of the positive electrode material was 6.8%. Other operations were the same as in Example 1.

[0037] Example 3

[0038] Li 2.3 Zr 0.7 Fe 0.3 Cl6 and 0.5Li2MnO3·0.5LiMn 1 / 3 Co 1 / 3 Ni 1 / 3 The mass ratio of O2 was 0.2:99.8. The molar ratio of Fe atoms on the surface of the positive electrode material was 0.5%. Other operations were the same as in Example 1.

[0039] Comparative Example 1

[0040] 50 mg of Li6PS5Cl was taken and placed in a mold, held under 1 ton of pressure for 5 minutes, and pressed into the solid electrolyte. 1 / 3 Co 1 / 3 Ni 1 / 3 O2, Li6PS5Cl, and conductive carbon black were weighed in a 70:29:1 mass ratio, added to a mortar, and hand-ground for 20 minutes to obtain a composite cathode powder. Next, 10 mg of the composite cathode powder was placed on the solid electrolyte and held under 1 ton of pressure for 5 minutes to form a cathode sheet. After removal, the solid electrolyte was turned over and a metallic lithium piece was placed on the solid electrolyte side of the cathode sheet. The metallic lithium piece had a diameter of 10 mm. This was pressurized to 0.1 ton and maintained at this pressure to obtain an all-solid-state lithium-ion battery. The assembly process for the all-solid-state lithium-ion battery was completed in an argon-atmosphere glove box.

[0041] Comparative Example 2

[0042] Li 2.3 Zr 0.7 Fe 0.3 Cl6 and 0.5Li2MnO3·0.5LiMn 1 / 3 Co 1 / 3 Ni 1 / 3The mass ratio of O2 was 0.05:99.95. The molar ratio of Fe atoms on the surface of the positive electrode material was 0.1%, and the other operations were the same as in Example 1.

[0043] Comparative Example 3

[0044] Li 2.3 Zr 0.7 Fe 0.3 Cl6 and 0.5Li2MnO3·0.5LiMn 1 / 3 Co 1 / 3 Ni 1 / 3 The mass ratio of O2 was 15:85. The molar ratio of Fe atoms on the surface of the positive electrode material was 10%. Other operations were the same as in Example 1.

[0045] In Examples 1 to 3 of the present invention and Comparative Examples 1 to 3, lithium ion batteries were fabricated using different positive electrode materials. An electrochemical workstation manufactured by Wuhan Land Electronics Co., Ltd. was used in an environment of 25°C. Tests were conducted on the resulting all-solid-state lithium ion batteries in accordance with standard test methods for gram capacity and initial coulombic efficiency, with a voltage range of 2.0 V to 4.8 V and a test rate of 0.1 C. The performance test results of the lithium ion batteries of Examples 1 to 3 and Comparative Examples 1 to 3 are shown in Table 1.

[0046] [Table 1]

[0047] See Figures 2 to 5. Scanning electron microscope (SEM) images and EDS energy spectra of the coated positive electrode material produced in Example 1 are shown in Figures 2 and 3. As can be seen from Figures 2 and 3, a layer of coating material containing Fe element was present on the surface after the halide solid electrolyte was applied, and no damage was observed on the surface. The EDS energy spectra of the untreated positive electrode active material of Comparative Example 1 are shown in Figures 4 and 5. As can be seen from Figures 4 and 5, the particle surfaces of the uncoated lithium-excess manganese-based positive electrode material were smooth and did not contain Fe element. Therefore, in the present invention, the halide solid electrolyte can be uniformly coated on the particles of the lithium-excess manganese-based positive electrode material without affecting the particle morphology of the lithium-excess manganese-based positive electrode material.

[0048] See Table 1. Comparing Examples 1 to 3 with Comparative Example 1, coating with a halide solid electrolyte increased the gram capacity and improved the coulombic efficiency of the lithium-ion battery. That is, the halide solid electrolyte has high compatibility with high-voltage lithium-excess manganese-based positive electrode materials, effectively improving the ion transfer dynamics of the positive electrode material and thereby improving the rate performance of the battery. By coating the high-voltage lithium-excess manganese-based positive electrode material with a halide solid electrolyte, it effectively suppresses side reactions between the positive electrode material and the sulfide electrolyte at high voltages and improves the interfacial stability between the positive electrode and the solid electrolyte, thereby improving the stability and cycle performance of the lithium-ion battery.

[0049] See Table 1. Comparing Examples 1 to 3 with Comparative Examples 2 and 3, increasing or decreasing the molar ratio of Fe atoms on the surface of the positive electrode material simultaneously changed the amount of halide solid electrolyte coating. When the coating amount was too small, the small coating layer was unable to suppress the side reaction between the high-voltage positive electrode active material and the sulfide electrolyte, resulting in low initial Coulombic efficiency and positive electrode gram capacity. When the coating amount was too large, the halide solid electrolyte coating layer, with its low electronic conductivity, affected the electronic contact of the positive electrode active material, affecting the gram capacity. Therefore, by controlling the coating amount of the halide solid electrolyte on the surface of the positive electrode active material, it is possible to simultaneously improve the capacity and cycle characteristics of a lithium-ion battery.

[0050] The present invention also provides an electronic device. The electronic device includes at least one lithium-ion battery, which is used to supply electrical energy. Specifically, the electronic device may be a vehicle, a mobile phone, a portable device, a laptop, a boat, a spacecraft, an electric toy, a power tool, or the like. In one embodiment of the present invention, the vehicle is, for example, a new energy vehicle. The new energy vehicle may be a pure electric vehicle, a hybrid vehicle, a range-extended vehicle, or the like. The spacecraft may include an aircraft, a rocket, a space shuttle, a spaceship, or the like. The power toy may include a game console, a power toy car, a power toy boat, a power airplane, or other stationary or mobile power toy. The power tool may include a metal cutting power tool, a grinding power tool, an assembly power tool, or a railroad power tool. Examples include an electric drill, an electric grinder, an electric wrench, an electric screwdriver, an electric hammer, an impact drill, a concrete vibrator, an electric planer, or the like. Because the electronic device is equipped with a lithium-ion battery, the advantages of the lithium-ion battery are also included, although not described in detail here.

[0051] Based on the above, the present invention provides a positive electrode material, a manufacturing method, and applications thereof. By coating a positive electrode active material with a halide solid electrolyte and doping the halide solid electrolyte with iron, a low-cost, high-ionic conductivity, and high-voltage halide solid electrolyte can be obtained, thereby solving the problem of interfacial instability between high-voltage lithium-excess manganese-based positive electrode materials and sulfide solid electrolytes. The halide solid electrolyte has high compatibility with high-voltage lithium-excess manganese-based positive electrode materials, improving the lithium ion conductivity of the positive electrode material and effectively improving ion transfer dynamics, thereby improving the rate performance of the battery. This effectively suppresses side reactions between the positive electrode material and the sulfide electrolyte at high voltages, improving the interfacial stability between the electrode and the solid electrolyte, and thereby improving the stability and cycle performance of the battery. The Fe element in the halide solid electrolyte has a stronger bonding ability with the O element in the lithium-excess manganese-based positive electrode material, which is beneficial for improving the reversible oxidation-reduction ability of oxygen during cycling, thereby suppressing the dissolution of transition metals and the release of oxygen from the positive electrode, and improving the initial coulomb efficiency and cycle life.

[0052] The above description is merely a preferred embodiment of the present application and merely describes the technical principles used. Those skilled in the art should understand that the scope of the present invention is not limited to the technical solution formed by a specific combination of the above technical features, but should also encompass other technical solutions formed by any combination of these technical features. Without departing from the concept of the present invention, the present invention includes (but is not limited to) the above technical features or their equivalent features, for example, technical solutions formed by replacing the above features with technical features having similar functions disclosed in the present application.

[0053] Except for the technical features described in this specification, the remaining technical features are known to those skilled in the art, and in order to highlight the innovative features of the present invention, the remaining technical features will not be described in detail here. [Industrial Applicability]

[0054] The positive electrode material and manufacturing method provided by the present invention can be applied to lithium ion batteries. [Explanation of symbols]

[0055] S100, S200: Process

Claims

1. a positive electrode active material; a coating layer that coats the positive electrode active material and contains a halide solid electrolyte; At least The positive electrode active material is nLi ２ MnO ３ ・(1-n)LiMn ａ Co ｂ Ni ｃ O ２ wherein 0.2≦n≦0.5 and a+b+c=1, and the chemical formula of the halide solid electrolyte is Li ２＋ｍ Zr １－ｍ Fe ｍ Cl ６－ｘ－ｙ Br ｘ I ｙ wherein 0<m≦0.5, x=0 to 6, y=0 to 6, and x+y≦6; a molar ratio of iron atoms on a surface of the positive electrode material measured with an energy dispersive X-ray analyzer is 0.4% to 7%.

2. The chemical formula of the halide solid electrolyte is Li ２．３ Zr ０．７ Fe ０．３ Cl ６ The positive electrode material for an all-solid-state lithium ion battery according to claim 1,

3. 2. The cathode material for an all-solid-state lithium-ion battery according to claim 1, wherein the cathode active material is spherical.

4. 4. The positive electrode material for an all-solid-state lithium-ion battery according to claim 3, wherein the spherical positive electrode active material has a median diameter D50 of 8 μm to 20 μm.

5. Mixing compounds containing Li, Zr, and Fe elements in corresponding amounts, and then grinding and primary sintering to obtain a halide solid electrolyte according to the chemical formula of the halide solid electrolyte; mixing the halide solid electrolyte and the positive electrode active material in accordance with a mass ratio and subjecting the mixture to secondary firing to obtain a positive electrode material; A method for producing a positive electrode material comprising at least a molar ratio of iron atoms on the surface of the positive electrode material measured with an energy dispersive X-ray analyzer is 0.4% to 7%.

6. 6. The method for producing a positive electrode material for an all-solid-state lithium ion battery according to claim 5, wherein a mass ratio of the halide solid electrolyte to the positive electrode active material is (0.2 to 6):(99.9 to 94).

7. 6. The method for producing a positive electrode material for an all-solid-state lithium ion battery according to claim 5, wherein the mixing conditions include a mixing speed of 100 rpm to 800 rpm and a mixing time of 1 hour to 6 hours.

8. The method for producing a positive electrode material for an all-solid-state lithium ion battery according to claim 5, wherein the secondary baking temperature is 950°C to 1050°C, and the sintering time is 6 hours to 18 hours.

9. An all-solid-state lithium ion battery comprising the positive electrode material for an all-solid-state lithium ion battery according to any one of claims 1 to 4.

10. An electronic device comprising the positive electrode material for an all-solid-state lithium-ion battery according to claim 1.

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