Positive electrode active material and preparation method thereof, positive electrode and lithium ion secondary battery

Abstract

The invention discloses a high-voltage lithium ion battery positive electrode active material and a preparation method thereof. The positive electrode active material is of a core-shell structure, the chemical formula of an inner core is a lithium-containing compound of LiNi < 0.25 + / -a > Mn < 1.75 + / -b > McO4-d, the chemical formula of a shell is a lithium-containing compound of LiNi < 0.5 + / -m > Mn < 1.5 + / -n > NxO4-y, M and N are selected from one or more doping elements of Mg, Zn, Ni, Mn, Fe, Co, Ti, Cr, Y, Sc, Ru, Cu, Mo, Ge, W, Zr, Ca, Ta, Sr, Al, Nb, B, P, Si, F and S, the doping forms comprise uniform doping and gradient doping,-0.05 < = a < = 0.05,-0.0.5 < = b < = 0.05, 0 < = c < = 0.1,-0.2 < = d < = A transition layer is arranged between the inner core and the shell, and the transition layer diffuses into the shell and optional calcination. Compared with the prior art, the spinel positive electrode active material for the lithium ion battery provided by the invention has a core-shell structure and excellent high-temperature cycle performance. Meanwhile, the technical scheme provided by the invention is also suitable for industrial production.

Description

Technical Field

[0001] The present invention belongs to the technical field of lithium battery materials, and in particular relates to a high-voltage positive electrode active material and a preparation method thereof, a positive electrode and a lithium ion secondary battery. Background Art

[0002] Lithium-ion secondary batteries, due to their excellent performance, are widely used in portable electronic devices and next-generation electric vehicles. Lithium nickel manganese oxide, a spinel high-voltage material developed from lithium manganese oxide, is considered the most likely cathode material for next-generation high-energy-density power batteries due to its high operating voltage (4.7V), excellent rate capability, and low cost.

[0003] Studies have shown that the surface structure of this material is very unstable during high temperature cycling, and it reacts with traditional carbonate electrolytes, causing the surface of the positive electrode material to be continuously oxidized and decomposed, resulting in severe capacity decay. In addition, due to the material's Mn 3+ The presence of manganese in the material makes it prone to disproportionation reactions, and manganese dissolves during the cycle, ultimately leading to material capacity decay. These factors have inhibited the large-scale application of spinel lithium nickel manganese oxide.

[0004] In order to improve the high-temperature electrochemical performance of the positive electrode material, researchers often use reconstructing the material surface to improve the performance of the material. Traditional coating methods coat the precursor material, which is uneven. At the same time, coating only solves the surface stability problem, but does not reduce self-discharge and improve rate performance. Summary of the Invention

[0005] In view of the above technical problems, one of the purposes of the present invention is to provide a core-shell structure positive electrode active material and its preparation method and application, so as to obtain a positive electrode active material with relatively uniform coating, and at the same time, the positive electrode active material can reduce the voltage of the traditional lithium nickel manganese oxide material (LiNi 0.5 Mn 1.5 O4), and maintain surface stability while the voltage is slightly reduced, so that the electrolyte decomposition and surface side reactions of the positive electrode material are suppressed under high charging voltage and high temperature conditions, thereby improving its capacity retention rate and charge and discharge coulomb efficiency.

[0006] To achieve the above purpose, the technical solution provided by the present invention is:

[0007] Provided are a high-voltage lithium-ion battery positive electrode active material and a preparation method thereof.

[0008] The positive electrode active material comprises a core spinel lithium nickel manganese oxide and a shell spinel lithium nickel manganese oxide covering the core, and a transition layer formed between the two. The core lithium nickel manganese oxide is a LiNi with a spinel structure. 0.25±a Mn 1.75±b M c O 4-d , wherein M is selected from one or more doping elements selected from Mg, Zn, Ni, Mn, Fe, Co, Ti, Cr, Y, Sc, Ru, Cu, Mo, Ge, W, Zr, Ca, Ta, Sr, Al, Nb, B, P, Si, F and S, -0.05≤a≤0.05, -0.0.5≤b≤0.05, 0≤c≤0.1, -0.2≤d≤0.2. The lithium nickel manganese oxide of the shell is LiNi with a spinel structure 0.5±m Mn 1.5±n N x O 4-y , wherein N is selected from one or more doping elements of Mg, Zn, Ni, Mn, Fe, Co, Ti, Cr, Y, Sc, Ru, Cu, Mo, Ge, W, Zr, Ca, Ta, Sr, Al, Nb, B, P, Si, F and S, 0 <m≤0.1,0<n≤0.1,0≤x≤0.1,-0.2≤y≤0.2;

[0009] The transition layer formed between the core and the shell of the spinel lithium nickel manganese oxide material is LiNi e Mn f R g O h , wherein R is selected from one or more doping elements of Mg, Zn, Ni, Mn, Fe, Co, Ti, Cr, Y, Sc, Ru, Cu, Mo, Ge, W, Zr, Ca, Ta, Sr, Al, Nb, B, P, Si, F and S, 0.2≤e≤0.6, 1.4≤f≤1.8, 0≤g≤0.1, and 3.8≤z≤4.2.

[0010] Among them, the core lithium nickel manganese oxide LiNi 0.25±a Mn 1.75±b M c O 4-d The atomic ratio of manganese and nickel elements is 5.6-9, and the shell is lithium nickel manganese oxide LiNi 0.5±m Mn 1.5±n N x O 4-y The atomic number ratio of manganese and nickel elements is 2.2-4.

[0011] The particle size D50 of the positive electrode active material is 2 to 30 μm. 0.5±m Mn 1.5±n N x O 4-y The thickness is 2nm~500nm.

[0012] A method for preparing a positive electrode active material for a high-voltage lithium-ion battery, characterized by comprising the following steps:

[0013] (1) A lithium source, a nickel source, a manganese source, and an M source are mixed in proportion to obtain a precursor A, and the precursor A is sintered in air to obtain the core lithium nickel manganese oxide according to claim 2, wherein the sintering temperature is 250° C. to 1100° C.

[0014] (2) Mixing a lithium source, a nickel source, a manganese source, and a nitrogen source, adding the material obtained in step (1) to the aforementioned mixture to obtain a precursor B, and sintering the precursor B in an air atmosphere to prepare the positive electrode material, wherein the sintering temperature is 250°C to 1100°C.

[0015] Wherein, the nickel source is one or more of nickel oxide, nickel hydroxide, nickel nitrate, nickel oxalate, nickel carbonate, nickel bicarbonate, nickel manganese hydroxide, nickel manganese carbonate and nickel acetate; and / or the manganese source is one or more of manganese-containing oxide, manganese hydroxide, manganese nitrate, manganese oxalate, manganese carbonate, manganese bicarbonate and manganese acetate; and / or the lithium source is one or more of lithium hydroxide, lithium carbonate, lithium acetate, lithium oxalate and lithium citrate;

[0016] Among them, the M source or the N source is a single substance or compound containing at least one element of Mg, Zn, Ni, Mn, Fe, Co, Ti, Cr, Y, Sc, Ru, Cu, Mo, Ge, W, Zr, Ca, Ta, Sr, Al, Nb, B, P, Si, F and S.

[0017] The present application also relates to a lithium-ion secondary battery positive electrode, which includes a current collector on which is loaded any of the above-mentioned composite spinel structure positive electrode active materials.

[0018] The present application also relates to a lithium-ion secondary battery, which comprises a negative electrode and the above-mentioned lithium-ion secondary battery positive electrode.

[0019] In addition to the aforementioned components, any other modifications of the positive electrode active material, such as any form of carbon black coating on the positive electrode active material, including coating of various carbon nanotubes, graphene and other carbon-containing substances, and any form of phosphate, borate and silicate coating, are still within the scope of protection of this patent.

[0020] At the same time, this material can also be combined with the existing LiNi 0.5 Mn 1.5 O4 materials are mixed to increase LiNi 0.5 Mn 1.5 Electrochemical properties of O4.

[0021] Therefore, any material that meets the composition distribution specified in this patent is within the scope of protection. While protected by this patent, the introduction of other structures and components can further enhance the stability of the material, and the enforcement of the rights to the newly synthesized material remains within the scope of protection of this patent.

[0022] The characteristics of the materials disclosed in this patent can be characterized by scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM), high-resolution TEM and X-ray photoelectron spectroscopy (XPS), secondary ion mass spectrometry, inductively coupled plasma (ICP), and corresponding microscopic imaging, electronic imaging spectral imaging, etc., wherein the structure of the material can be determined by XRD first, and then the material can be cut by laser ion beam to characterize the spectrum of its cross-sectional area, or the secondary ion mass spectrometry can be directly used to characterize the composition at different depths in the longitudinal direction. To prove the composition distribution of the materials disclosed in this patent, the above methods, but not limited to the above methods, can determine whether the positive electrode active material precursor is within the scope of protection of this patent.

[0023] The beneficial effects of the present invention are:

[0024] The lithium battery positive electrode active material provided by this invention has a core-shell structure, with the core differing in structure and composition from the shell. This characteristic gives the material a fundamentally different charge-discharge curve than traditional lithium nickel manganese oxide, effectively reducing the voltage of traditional lithium nickel manganese oxide and significantly improving the stability of the material.

[0025] Our research found that when the atomic ratio of manganese and nickel in lithium nickel manganese oxide material is close to 5.6-9, it can not only reduce the voltage platform of the final synthesized lithium nickel manganese oxide material, but also make lithium nickel manganese oxide less decomposition of the electrolyte during the charge and discharge process. And the bulk stability is very good and it is easy to synthesize. More importantly, the lithium nickel manganese oxide synthesized by this precursor has lower resistivity, and due to the decrease in resistivity and the increase in conductivity, the polarization is also reduced and the side reactions are reduced, which are all conducive to cycling. When the atomic ratio is not within this range, it will lead to higher resistivity or a serious reduction in energy density, or because of the excessive increase in manganese elements, the Jan-Taylor effect is obvious, and the bulk structure of the lithium nickel manganese oxide material is unstable.

[0026] However, the surface stability of this core structure is insufficient. Therefore, our research found that when the atomic ratio of manganese and nickel in the lithium nickel manganese oxide precursor material of the shell component is close to 1.5-4, although the voltage platform of lithium embedding is relatively high with this ratio and composition, this component only exists in a very thin layer on the surface. Therefore, the average voltage of the entire material is still determined by the lithium nickel manganese oxide in the inner layer. However, this thin layer has a high content of nickel and therefore has a strong oxidation resistance. Moreover, although the resistivity of this component is relatively high, since the surface of the nickel manganese material is in direct contact with carbon black, it can be compensated by increasing the carbon black content in the electrode and improving the quality of the carbon black in the electrode later.

[0027] Furthermore, the biggest problem currently restricting the industrialization of lithium nickel manganese oxide is the self-discharge of the material at high temperatures. On the one hand, this structure reduces the voltage, and on the other hand, the surface has extremely high stability, thereby reducing self-discharge.

[0028] In summary, the material synthesized by the above structure and composition reduces the resistivity of lithium nickel manganese oxide by reducing the average discharge voltage of lithium nickel manganese oxide, while improving the surface stability. The synergistic effect of the shell and the core can effectively slow down the reaction between the material and the electrolyte, inhibit the decomposition of the electrolyte and the occurrence of surface side reactions under high voltage, reduce the dissolution and precipitation of ions on the surface of the material, improve the stability of the surface structure of the material, and improve the cycle stability and coulomb efficiency of the material. Materials outside this range will either have aggravated bulk instability, or have too large a bulk internal resistivity and be unsuitable for fast charging, or have insufficient surface stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The capacity retention rate and capacity recovery rate of the charged electrodes containing the positive electrode active materials of Example 1 and Comparative Example 3 after immersion in an electrolyte at 55° C. for 3 days. DETAILED DESCRIPTION

[0030] The technical solutions of the present invention are described in detail below through specific implementation methods. The following examples are only intended to illustrate the present invention, rather than to limit the scope of implementation of the present invention.

[0031] Example 1:

[0032] (1) Lithium carbonate, nickel acetate, and manganese acetate were dissolved in a citric acid solution in a molar ratio of 0.5:0.3:1.7, and heated and stirred at 150°C until completely dissolved to form a solution 1. The solution was then heated and stirred at 150°C to evaporate the water to form a dry powder. The ground powder was then placed in a box furnace and calcined at 900°C for 10 hours to obtain a preliminary spinel lithium nickel manganese oxide.

[0033] (2) Lithium carbonate, nickel acetate, and manganese acetate are dissolved in a citric acid solution in a molar ratio of 0.5:0.55:1.45, and heated and stirred at 150° C. until completely dissolved to form a second solution. 1 mol of the core spinel lithium nickel manganese oxide powder obtained in step (1) is added to the second solution containing 0.03 mol of lithium element to obtain a suspension, and the suspension is further heated and stirred at 150° C. to evaporate the water to form a dry powder. The ground powder is then placed in a box furnace and calcined at 800° C. for 10 h to finally obtain a special high-voltage spinel lithium nickel manganese oxide with a core-shell structure.

[0034] Example 2:

[0035] (1) Lithium carbonate, nickel acetate, manganese acetate, and ammonium metatungstate were dissolved in a citric acid solution in a molar ratio of 0.5:0.3:1.69:0.1, and heated and stirred at 150°C until completely dissolved to form a solution 1. The solution was then heated and stirred at 150°C to evaporate the water to form a dry powder. The ground powder was then placed in a box furnace and calcined at 900°C for 10 hours to obtain a core spinel lithium nickel manganese oxide.

[0036] (2) Lithium carbonate, nickel carbonate, manganese carbonate, and ammonium metatungstate are dissolved in a citric acid solution in a molar ratio of 1:0.6:1.39:0.1, and heated and stirred at 150° C. until completely dissolved to form a second solution. 1 mol of the manganese-rich spinel lithium nickel manganese oxide powder obtained in step (1) is added to the second solution having a lithium element content of 0.05 mol to obtain a suspension, and heating and stirring are continued at 150° C. to evaporate the water to form a dry powder. The ground powder is then placed in a box furnace and calcined at 900° C. for 10 h to obtain a special high-voltage spinel lithium nickel manganese oxide having a core-shell structure.

[0037] (3) The positive electrode obtained in step (2) was mixed with 1% acetylene black, and sintered at 200° C. for 3 h to finally obtain a carbon-coated high-voltage lithium nickel manganese oxide material with a core-shell structure.

[0038] Comparative Example 1:

[0039] Lithium carbonate, nickel acetate and manganese acetate were dissolved in a citric acid solution in a molar ratio of 0.5:0.3:1.7, and heated and stirred at 150°C until completely dissolved to form a solution. The solution was then heated and stirred at 150°C to evaporate the water to form a dry powder. The ground powder was then placed in a box furnace and calcined at 900°C for 10 hours to finally obtain spinel lithium nickel manganese oxide of Comparative Example 1.

[0040] Comparative Example 2:

[0041] Lithium carbonate, nickel acetate and manganese acetate were dissolved in a citric acid solution in a molar ratio of 0.5:0.6:1.4, and heated and stirred at 150°C until completely dissolved to form a solution. The solution was then heated and stirred at 150°C to evaporate the water to form a dry powder. The ground powder was then placed in a box furnace and calcined at 900°C for 10 hours to finally obtain spinel lithium nickel manganese oxide of Comparative Example 2.

[0042] Comparative Example 3:

[0043] Will purchase LiNi from Rongbai Technology 0.5 Mn 1.5 O4 is used as the positive electrode material in Comparative Example 3.

[0044] Electrochemical performance test

[0045] First, the positive electrode active materials prepared in Examples 1-4 were prepared into button-type batteries according to the following method.

[0046] 1) Preparation of positive electrode sheet

[0047] The positive electrode active materials prepared in Examples 1-2 and Comparative Examples 1-2, carbon black as a conductive additive, and polyvinylidene fluoride (PVDF) as a binder were dispersed in N-methylpyrrolidone (NMP) at a weight ratio of 80:10:10 and mixed uniformly to prepare a uniform positive electrode slurry. The uniform positive electrode slurry was evenly coated on a 15 μm thick aluminum foil current collector and dried at 55°C to form a 100 μm thick electrode sheet. The electrode sheet was placed on a roller press (pressure of approximately 1 MPa × 1.5 cm2) and cut into discs with a diameter of φ14 mm. The discs were then placed in a vacuum oven at 120°C for 6 hours, naturally cooled, and then removed and placed in a glove box for use as positive electrode sheets.

[0048] 2) Assembling lithium-ion secondary batteries

[0049] In a glove box filled with an inert atmosphere, metallic lithium was used as the negative electrode of the battery, and a three-layer PP / PE / PP film coated with aluminum oxide on both sides was placed between the positive and negative electrodes as a separator. A commonly used carbonate electrolyte was added dropwise, and the positive electrode sheet prepared in step 1) was used as the positive electrode to assemble a button battery with a model number of CR2032.

[0050] Battery electrode self-discharge test:

[0051] The button battery prepared above was left standing at room temperature (25°C) for 10 hours, and then activated by charge and discharge at 0.1C. The battery was then charged to a full charge at a rate of 0.1C, and the battery was disassembled. The positive electrode sheet was soaked in an electrolyte at 55°C. After soaking for 7 days, the battery was reassembled and cycled. The ratio of the discharge capacity in the first week to the discharge capacity in the activation stage was the capacity retention rate, and the ratio of the cycle capacity in the second week to the capacity in the activation stage was the capacity recovery rate.

[0052] Battery rate cycle performance test:

[0053] The button cell prepared above was left at room temperature (25°C) for 10 hours, and then activated by charge and discharge at a rate of 0.1C. Subsequently, a charge and discharge cycle test was performed on the button cell prepared above using a Blue Power battery charge and discharge tester. The details are as follows:

[0054] 1) The discharge capacity and coulombic efficiency of button cells assembled with the positive electrode active materials of Examples 1-2 and Comparative Examples 1-2 were tested at 55° C. and 0.2C rate for 100 cycles, as shown in Table 1.

[0055] Table 1

[0056]

[0057] It can be concluded from Table 1 above that Examples 1 and 2 are spinel lithium nickel manganese oxide materials with a core-shell structure, Comparative Example 1 is a lithium nickel manganese oxide material with a relatively high manganese content, and Comparative Example 2 is a lithium nickel manganese oxide material with a relatively high nickel content. After 100 cycles, Examples 1 and 2 have small capacity decay and high coulombic efficiency. For the material of Comparative Example 1, the discharge capacity is high, the decay is fast, and the coulombic efficiency is low, while for the material of Comparative Example 2, the capacity is low, but the decay is slower, and the coulombic efficiency is high. Therefore, the high-temperature cycle performance of the spinel lithium nickel manganese oxide material with a core-shell structure is significantly improved. At the same time, the electrochemical curve of the lithium nickel manganese oxide material prepared in Example 1 has an average voltage of about 4.55V, which is somewhat different from the average voltage of about 4.7V of conventional lithium nickel manganese oxide, indicating that the material prepared by the present invention reduces the average working voltage of spinel lithium nickel manganese oxide.

[0058] The resistivity and average discharge voltage of the positive electrode active materials of Test Examples 1-2 and Comparative Examples 1-2 are shown in Table 2;

[0059] Table 2

[0060]

[0061] Table 2 shows that the positive electrode active material disclosed in this patent has both lower resistivity and lower discharge voltage. Combined with Table 1, it can be seen that the material also has the best stability. This is due to the ratio of manganese to nickel in the core of the materials in Examples 1 and 2 being 5.6-8, and the ratio of manganese to nickel in the outer shell being 2.2-4.

[0062] Table 3 shows the capacity retention and capacity recovery of the charged electrodes containing the positive electrode active materials of Example 1 and Comparative Example 3 after being immersed in an electrolyte at 55° C. for 3 days.

[0063] Table 3

[0064] serial number Example 1 Comparative Example 3 Self-discharge temperature (℃) 55 55 Self-discharge time (h) 168 168 Capacity retention rate (%) 92 52 Capacity recovery rate (%) 97 91

[0065] It can be clearly seen from Table 3 that Example 1 has better capacity retention and capacity recovery after the self-discharge test.

[0066] The present application also relates to a lithium-ion secondary battery positive electrode, which includes a current collector on which the above-mentioned composite spinel structure positive electrode active material is loaded.

[0067] The present application also relates to a lithium-ion secondary battery, which includes a separator, an electrolyte, a negative electrode and the above-mentioned lithium-ion secondary battery positive electrode.

[0068] According to the explanation and teaching of the above description, those skilled in the art to which the present invention belongs may also change and modify the above-mentioned embodiments. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some modifications and changes to the present invention should also fall within the scope of protection of the claims of the present invention. In addition, although some specific terms are used in this specification, these terms are only for convenience of explanation and do not constitute any limitation to the present invention. As described in the above-mentioned embodiments of the present invention, other materials, preparation methods, and applications obtained by the same or similar methods and components are all within the scope of protection of the present invention.

Claims

1. A positive electrode active material for a lithium secondary battery, wherein the positive electrode active material comprises a core spinel lithium nickel manganese oxide and a shell spinel lithium nickel manganese oxide covering the core, and a transition layer formed between the core and the shell. The core lithium nickel manganese oxide is a LiNi with a spinel structure. 0.25±a Mn 1.75±b M c O 4-d , wherein M is selected from one or more doping elements selected from Mg, Zn, Ni, Mn, Fe, Co, Ti, Cr, Y, Sc, Ru, Cu, Mo, Ge, W, Zr, Ca, Ta, Sr, Al, Nb, B, P, Si, F and S, -0.05≤a≤0.05, -0.05≤b≤0.05, 0≤c≤0.1, -0.2≤d≤0.

2. The lithium nickel manganese oxide of the shell is LiNi with a spinel structure 0.5±m Mn 1.5±n N x O 4-y , wherein N is selected from one or more doping elements of Mg, Zn, Ni, Mn, Fe, Co, Ti, Cr, Y, Sc, Ru, Cu, Mo, Ge, W, Zr, Ca, Ta, Sr, Al, Nb, B, P, Si, F and S, 0≤m<0.1, 0≤n<0.1, 0≤x≤0.1, -0.2≤y≤0.

2.

2. According to claim 1, it is characterized in that The transition layer formed between the core and the shell of the spinel lithium nickel manganese oxide material is LiNi e Mn f R g O h , wherein R is selected from one or more doping elements of Mg, Zn, Ni, Mn, Fe, Co, Ti, Cr, Y, Sc, Ru, Cu, Mo, Ge, W, Zr, Ca, Ta, Sr, Al, Nb, B, P, Si, F and S, 0.2≤e≤0.6, 1.4≤f≤1.8, 0≤g≤0.1, and 3.8≤z≤4.

2.

3. According to claim 1, it is characterized in that Core lithium nickel manganese oxide LiNi 0.25±a Mn 1.75±b M c O 4-d The atomic ratio of manganese and nickel elements is 5.6-9, and the shell is lithium nickel manganese oxide LiNi 0.5±m Mn 1.5±n N x O 4-y The atomic number ratio of manganese and nickel elements is 2.2-4.

4. The positive electrode active material according to any one of claims 1 to 3, characterized in that The particle size D50 of the core lithium nickel manganese oxide is 2 to 30 μm.

5. The positive electrode active material according to any one of claims 1 to 4, characterized in that The thickness of the shell lithium nickel manganese oxide is 2nm to 500nm.

6. A method for preparing a positive electrode active material according to any one of claims 1 to 5, characterized in that: The following steps are involved: (1) A lithium source, a nickel source, a manganese source, and an M source are mixed in proportion to obtain a precursor A, and the precursor A is sintered in air to obtain the core lithium nickel manganese oxide according to claim 2, wherein the sintering temperature is 250° C. to 1100° C. (2) Mixing a lithium source, a nickel source, a manganese source, and a nitrogen source, adding the material obtained in step (1) to the aforementioned mixture to obtain a precursor B, and sintering the precursor B in an air atmosphere to prepare the positive electrode material, wherein the sintering temperature is 250°C to 1100°C.

7. The method for preparing the lithium nickel manganese oxide material according to claim 6, wherein: The nickel source is one or more of nickel oxide, nickel hydroxide, nickel nitrate, nickel oxalate, nickel carbonate, nickel bicarbonate, nickel manganese hydroxide, nickel manganese carbonate and nickel acetate; and / or the manganese source is one or more of manganese-containing oxide, manganese hydroxide, manganese nitrate, manganese oxalate, manganese carbonate, manganese bicarbonate and manganese acetate; and / or the lithium source is one or more of lithium hydroxide, lithium carbonate, lithium acetate, lithium oxalate and lithium citrate.

8. The method for preparing a positive electrode active material according to any one of claims 6 to 7, wherein the M source or the N source is a simple substance or compound containing at least one element selected from the group consisting of Mg, Zn, Ni, Mn, Fe, Co, Ti, Cr, Y, Sc, Ru, Cu, Mo, Ge, W, Zr, Ca, Ta, Sr, Al, Nb, B, P, Si, F, and S.

9. A positive electrode for a lithium ion secondary battery, comprising a current collector, characterized in that: The positive electrode active material according to any one of claims 1 to 8 is supported on the current collector.

10. A lithium ion secondary battery, characterized in that: The lithium ion secondary battery comprises the positive electrode according to claims 1 to 9.

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