Zinc-containing positive electrode material for sodium ion battery, production method thereof, and use thereof

Abstract

To provide a zinc-containing cathode material for a sodium ion battery, which has a low residual alkali content, and avoids the occurrence of gelation phenomenon in a battery slurry preparation process, the capacity and rate of the sodium ion battery prepared using the zinc-containing cathode material being at a relatively high level, and a preparation method thereof.SOLUTION: The general formula of a cathode material is Na1+aMyZnxO2+c, where -0.40≤a≤0.25, 0.1<x≤0.22, 0.78<y≤0.93, and -0.3<c<0.3 are satisfied, and M is one or a combination of two or more elements selected from among Mn, Fe, Ni, Co, Al, Zr, Y, Ca, Li, Rb, Cs, W, Ce, Mo, Ba, Ti, Mg, Ta, Nb, V, Sc, Sr, B and Cu. In the powder X-ray diffraction pattern of the cathode material, at least five diffraction peaks exist when 2θ is 30° to 40°, a second strongest peak exists when 2θ is around 16° and a first strongest peak exists when 2θ is around 41°.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This invention relates to the technical field of sodium-ion batteries, and more specifically to a positive electrode material for sodium-ion batteries, a method for manufacturing it, and its applications. [Background technology]

[0002] Concerns about global lithium resources and the need for new large-scale energy storage are driving the continuous development of new battery fields. Thanks to the rich experience with lithium-ion batteries, sodium-ion batteries are developing rapidly. Among them, the cathode materials for sodium-ion batteries mainly include layered and tunnel-type transition metal oxides, polyanionic compounds, Prussian blue analogs, and organic materials. Research and development of sodium-ion batteries, along with research on these systems, is being pursued with efforts toward low cost and practical application. In 2011, Komaba et al. in Japan were the first to develop a hard carbon||NaNi 0.5 Mn 0.5 The characteristics of a complete O2 battery were reported. Also in this year, FARADION, a British company, was established as the world's first sodium-ion battery company. In 2013, Goodenough et al. in the United States proposed a Prussian white cathode material with high voltage and excellent rate characteristics, and in 2014, Hu Yongsheng et al. in China were the first to use Cu in a layered oxide. 3+ / Cu 2+ We discovered the electrochemical activity of redox pairs and designed and manufactured a series of low-cost Cu-based cathode materials.

[0003] Cathode oxides for sodium-ion batteries mainly consist of layered structure oxides and tunnel structure oxides. Of these, tunnel structure oxides have a unique "S"-shaped channel in their crystal structure, resulting in good rate characteristics and high stability against air and water. However, their initial charge-discharge ratio is low, resulting in a small usable specific capacity. Layered structure oxides have a periodic layered structure, are easy to manufacture, and have high specific capacity and voltage, making them the main cathode material for sodium-ion batteries. However, in the manufacturing process of layered oxides, it is common to add an excess of sodium salt to account for the loss of sodium element. As a result, sodium salt remains after the firing of the material, mainly in the form of sodium carbonate and sodium hydroxide, which is abbreviated as residual alkali. This causes most of the surface of the cathode material to absorb moisture or react with air and degrade easily, leading to poor compatibility with adhesives and reduced dispersibility and stability of the slurry, which is disadvantageous for subsequent coating processes. In addition, basic compounds on the surface increase irreversible capacity loss and worsen cycle characteristics. In conventional technology, layered oxides are mainly cobalt-based, manganese-based, nickel-iron-manganese, or nickel-iron-copper-manganese, and layered oxide cathode materials are obtained by modifying these substrates. Of these, cobalt-based cathode materials mainly use the rare cobalt metal, which is not only limited in resources but also very expensive. In nickel-iron-manganese or nickel-iron-copper-manganese cathode materials, nickel is a precious metal element, which not only makes them expensive but also necessitates production under oxygen conditions if the nickel content exceeds a certain ratio. The use of these rare precious metal elements is disadvantageous for widespread adoption in energy storage or low-end market sectors where cost requirements are stringent, thus necessitating the development of new low-cost cathode materials for sodium-ion batteries. [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] In view of the above technical problems, an object of the present invention is to provide a zinc-containing cathode material for a sodium-ion battery and a method for manufacturing the same. Through a large number of experimental studies, the present inventors have discovered the following. By replacing some rare precious metals with zinc elements, the crystal structure of the material can be stabilized. Particularly in the charge and discharge process of a sodium-ion battery, although sodium ions are frequently released, the presence of zinc oxide has a supporting effect, effectively reducing the collapse of the material structure, providing pores for the occlusion of sodium ions, and ensuring the rate performance of the material. In addition, since the content of residual alkali on the surface of the sodium-ion cathode material obtained by the manufacturing method is reduced, the phenomenon of gelation does not occur in the process of preparing the battery slurry, and the capacity and rate of the sodium-ion battery can be maintained at a relatively high level.

Means for Solving the Problems

[0005] Specifically, the present invention provides the following technical solutions. In a first aspect, the present invention provides a cathode material for a sodium-ion battery. The general formula of the cathode material is Na 1+a M d Zn x O 2+c where -0.40 ≤ a ≤ 0.25, 0.78 < d ≤ 0.93, 0.1 < x ≤ 0.22, -0.3 < c < 0.3, M is selected from one or more of the elements Mn, Fe, Ni, Co, Al, Zr, Y, Ca, Li, Rb, Cs, W, Ce, Mo, Ba, Ti, Mg, Ta, Nb, V, Sc, Sr, B, and Cu. However, there is one diffraction peak near 16° of the diffraction angle 2θ value, and at least five diffraction peaks exist at 30 - 40° of the diffraction angle 2θ value, preferably six diffraction peaks exist, and there is one diffraction peak near 41° of the diffraction angle 2θ value.

[0006] Preferably, in the cathode material Na 1+a M y Zn x O 2+c for a sodium-ion battery, M contains element A and element B, and the general formula of the cathode material is Na1+a B 1-b-x Zn x A b O 2+c and wherein 0.1 < x ≦ 0.22, 0.0 < b ≦ 0.06, -0.40 ≦ a ≦ 0.25, -0.3 < c < 0.3, y = 1 - x; and A and B are each independently selected from one or more of the elements Mn, Fe, Ni, Co, Al, Zr, Y, Ca, Li, Rb, Cs, W, Ce, Mo, Ba, Ti, Mg, Ta, Nb, V, Sc, Sr, B, and Cu, and A and B may be the same or different.

[0007] More preferably, the B element in the positive electrode material for the sodium ion battery is selected from one or more of Mn, Fe, Ni, and Co.

[0008] Even more preferably, the general formula of the positive electrode material for the sodium ion battery is Na 1+a Ni y Mn z Fe 1-x-y-z-b [[ID=2�]]Zn x A b O 2+c and wherein 0.15 ≦ y ≦ 0.35, 0.20 ≦ z ≦ 0.38, -0.40 ≦ a ≦ 0.25, 0.0 < b ≦ 0.06, -0.3 < c < 0.3, 0.1 < x ≦ 0.22. <了

[0009] Even more preferably, the general formula of the positive electrode material for the sodium ion battery is Na 1+a Ni y Mn z Fe 1-x-y-z-b Zn x A b O 2+c and wherein 0.20 ≦ y ≦ 0.32, 0.27 ≦ z ≦ 0.34, -0.40 ≦ a ≦ 0.25, 0.0 < b ≦ 0.06, -0.3 < c < 0.3, 0.1 < x ≦ 0.22.

[0010] Preferably, the mass percentage content of the zinc element in the positive electrode material for the sodium ion battery is 5.0 to 20.0%.

[0011] More preferably, the mass percentage content of Zn element in the positive electrode material for the sodium-ion battery is 5.0 to 15.0%.

[0012] More preferably, the mass percentage content of Zn element in the positive electrode material for the sodium-ion battery is 4.0 to 14.0%.

[0013] And / or, the mass percentage content of element M in the positive electrode material for the sodium-ion battery is 30-50%, preferably 34-45%, and more preferably 40-45%.

[0014] And / or, the mass percentage content of element Ni in the positive electrode material for the sodium-ion battery is 8 to 20%, preferably 11 to 16%.

[0015] And / or, the mass percentage content of Mn element in the positive electrode material for the sodium-ion battery is 10 to 20%, preferably 13 to 17%.

[0016] And / or, the mass percentage content of element Fe in the positive electrode material for the sodium-ion battery is 10-20%, preferably 13-20%, and more preferably 13-16%.

[0017] Preferably, the powder X-ray diffraction pattern of the positive electrode material for the sodium-ion battery indicates an α-NaFeO4 type layered structure.

[0018] Preferably, in the powder X-ray diffraction pattern of the positive electrode material for the sodium-ion battery, the full width at half maximum of the diffraction peak with a 2θ value of 30 to 40° is 0.04 to 0.4°, preferably 0.04 to 0.3°, and more preferably 0.04 to 0.2°.

[0019] And / or, a second strongest peak exists near 16° of 2θ, a first strongest peak exists near 41°, preferably a second strongest peak exists near 16.5° of 2θ, a first strongest peak exists near 41.6°, and / or, the full width at half maximum of the diffraction peaks where 2θ is near 16° and 41° is 0.05 to 0.35°, preferably 0.05 to 0.3°, and more preferably 0.05 to 0.2°.

[0020] Preferably, in the powder X-ray diffraction pattern of the positive electrode material for the sodium-ion battery, there are six diffraction peaks at a 2θ value of 30 to 40°, with their respective 2θ values ​​being around 32°, 33°, 34°, 35°, and 36°.

[0021] Preferably, the 2θ values ​​of the six diffraction peaks are around 31.8°, 33.4°, 34.4°, 35.2°, 36.3°, and 36.6°, respectively.

[0022] And / or, the full width at half maximum (FWHM) of the diffraction peak with a diffraction angle 2θ of approximately 31.8° is 0.06 to 0.25°, preferably 0.06 to 0.14°, and more preferably 0.07 to 0.14°.

[0023] And / or, the full width at half maximum (FWHM) of the diffraction peak with a diffraction angle 2θ of approximately 34.4° is 0.07 to 0.25°, preferably 0.06 to 0.13°.

[0024] And / or, the full width at half maximum (FWHM) of the diffraction peak with a diffraction angle 2θ of approximately 36.3° is 0.06 to 0.25°, preferably 0.06 to 0.15°, and more preferably 0.07 to 0.14°.

[0025] And / or, the ratio of the peak intensities of the diffraction peak with a diffraction angle 2θ around 31.8° and the diffraction peak with a diffraction angle 2θ around 34.4° is (1~2):1, preferably (1.2~1.8):1, and more preferably (1.3~1.7):1.

[0026] And / or, the ratio of the peak intensities of the diffraction peak with a diffraction angle 2θ around 36.3° and the diffraction peak with a diffraction angle 2θ around 34.4° is (2-3):1, preferably (2.2-2.8):1, and more preferably (2.2-2.7):1.

[0027] And / or, the full width at half maximum (FWHM) of a diffraction peak with a diffraction angle 2θ of around 16.5° is 0.08 to 0.25°, preferably 0.11 to 0.14°.

[0028] And / or, the full width at half maximum (FWHM) of a diffraction peak with a diffraction angle 2θ of approximately 33.4° is 0.08 to 0.23°, preferably 0.12 to 0.18°, and more preferably 0.148 to 0.18°.

[0029] And / or, the full width at half maximum (FWHM) of a diffraction peak with a diffraction angle 2θ of approximately 35.2° is 0.07 to 0.22°, preferably 0.13 to 0.18°.

[0030] And / or, the full width at half maximum (FWHM) of a diffraction peak with a diffraction angle 2θ of approximately 36.6° is 0.08 to 0.20°, preferably 0.12 to 0.16°, and more preferably 0.135 to 0.16°.

[0031] And / or, the full width at half maximum (FWHM) of the diffraction peak with a diffraction angle 2θ around 41.6° is 0.06 to 0.20°, preferably 0.09 to 0.14°.

[0032] Preferably, the specific surface area of ​​the positive electrode material for the sodium-ion battery is 0.25 to 1.5 m². 2 The particle size D50 of the positive electrode material for the sodium-ion battery is 2 to 15 μm.

[0033] More preferably, the specific surface area of ​​the positive electrode material for the sodium-ion battery is 0.69 to 1.5 m². 2The particle size D50 of the positive electrode material for the sodium-ion battery is 5.3 to 15 μm.

[0034] More preferably, the specific surface area of ​​the positive electrode material for the sodium-ion battery is 0.69 to 1.2 m². 2 The particle size D50 of the positive electrode material for the sodium-ion battery is 5.3 to 12 μm.

[0035] Preferably, the mass percentage content of residual alkali in the positive electrode material for the sodium-ion battery is 3.15% or less, preferably 0.7 to 3.15%, and more preferably 1.25 to 3.15%.

[0036] In a second embodiment, the present invention provides two methods for manufacturing a positive electrode material for a sodium-ion battery. The first manufacturing method includes the steps of uniformly mixing an M source, a Zn source, and a Na source, firing them at a temperature of 750 to 980°C and / or for a firing time of 8 to 40 hours, cooling, and grinding to obtain a positive electrode material for a sodium-ion battery.

[0037] The second manufacturing method includes the steps of obtaining a precursor by mixing an M source and Zn in a certain ratio, then uniformly mixing it with a Na source, firing it at a temperature of 750 to 980°C and / or firing for 8 to 40 hours, cooling it, and pulverizing it to obtain a positive electrode material for a sodium-ion battery.

[0038] Preferably, in the first manufacturing method, a ball milling method is employed for the uniform mixing, more preferably the ball milling frequency is 20 to 50 Hz, preferably 25 to 40 Hz, and / or the ball milling time is 10 to 60 minutes, preferably 10 to 45 minutes.

[0039] Preferably, the firing temperature is 880-960°C, and / or the firing time is 15-25 hours, and / or the heating rate is 3-10°C / min.

[0040] Preferably, the grinding is performed using a disc grinder, more preferably the distance between the discs is 0 to 2 mm and / or the rotational speed is 500 to 3000 revolutions per minute.

[0041] Preferably, the calcination gas is selected from air, oxygen, or a mixture thereof.

[0042] Preferably, the sodium source is selected from one or more of sodium hydroxide, sodium carbonate, sodium nitrate, sodium oxalate, sodium chloride, sodium fluoride, and sodium acetate.

[0043] And / or, the M source is selected from oxides of one or more elements from the elements Mn, Fe, Ni, Co, Al, Zr, Y, Ca, Li, Rb, Cs, W, Ce, Mo, Ba, Ti, Mg, Ta, Nb, V, Sc, Sr, B, and Cu, or salts thereof, or organic compounds thereof. Preferably, the M source is selected from carbonates, phosphates, nitrates, or oxides of one or more elements from among Mn, Fe, Ni, Co, Al, Zr, Y, Ca, Li, Rb, Cs, W, Ce, Mo, Ba, Ti, Mg, Ta, Nb, V, Sc, Sr, B, and Cu. More preferably, the M source is selected from one or more of manganese dioxide, manganese carbonate, nickel oxide, nickel carbonate, ferric oxide, ferrous oxalate, ferrous phosphate, and copper sulfate.

[0044] And / or, the A source is selected from oxides of one or more elements from the elements Co, Al, Zr, Y, Ca, Li, Rb, Cs, W, Ce, Mo, Ba, Ti, Mg, Ta, Nb, V, Sc, Sr, B, and Cu, or salts thereof, or organic compounds thereof. Preferably, the A source is selected from carbonates, phosphates, nitrates, or oxides of one or more elements from among Al, Zr, Y, Ca, Li, Rb, Cs, Ba, Ti, Mg, Nb, V, Sc, Sr, B, and Cu. More preferably, the A source is selected from one or more of the following: calcium oxide, boron oxide, niobium oxide, aluminum oxide, titanium oxide, magnesium oxide, copper oxide, yttrium oxide, zirconium oxide, or copper sulfate.

[0045] Preferably, the sodium ion cathode material is manufactured by the method for manufacturing the sodium ion battery cathode material described above.

[0046] In a third embodiment, the present invention provides a positive electrode for a sodium-ion battery comprising at least one of the sodium-ion battery positive electrode materials as a positive electrode active material.

[0047] In a fourth embodiment, the present invention provides a sodium-ion battery comprising a positive electrode, a negative electrode, and a sodium salt-containing electrolyte.

[0048] Preferably, the sodium-ion battery is used as a power source in power, energy storage systems, mobile storage devices, or electric vehicles.

[0049] Preferably, the sodium-ion battery is used in electric vehicles (xEVs), electric bicycles, electric motorcycles, A00 class electric vehicles, and the like.

[0050] In a fifth embodiment, the present invention provides a power, energy storage system, or mobile storage device manufactured using the sodium-ion battery. [Effects of the Invention]

[0051] The beneficial effects obtained in this invention are as follows: The cathode material for sodium-ion batteries provided by the present invention has a low residual alkali concentration on the surface, excellent air stability and rate characteristics, and the crystal structure of the material can be stabilized by replacing some of the rare noble metal nickel with zinc. In particular, during the charge and discharge process of sodium-ion batteries, sodium ions are frequently released, but the presence of zinc oxide provides a support effect, effectively reducing the collapse of the material structure and providing vacancies for the intercalation of sodium ions, thereby ensuring the rate characteristics of the material. The discharge capacity at 0.1C under conditions of 4-2V reaches 124.7Ah / g or more. [Brief explanation of the drawing]

[0052] [Figure 1] This is the XRD pattern of the sodium ion cathode material of Example 1. [Figure 2] This is a charge-discharge curve diagram of the sodium ion cathode material of Example 1. [Figure 3] This is the XRD pattern of the sodium ion cathode material of Example 2. [Figure 4] This is a charge-discharge curve diagram of the sodium ion cathode material of Example 2. [Figure 5] This is the XRD pattern of the sodium ion cathode material of Example 3. [Figure 6] This is a charge-discharge curve diagram of the sodium ion cathode material of Example 3. [Figure 7] This is the XRD pattern of the sodium ion cathode material of Example 4. [Figure 8] This is a charge-discharge curve diagram of the sodium ion cathode material of Example 4. [Figure 9] This is the XRD pattern of the sodium ion cathode material of Example 5. [Figure 10] This is a charge-discharge curve diagram of the sodium ion cathode material of Example 5. [Figure 11] This is the XRD pattern of the sodium ion cathode material of Example 6. [Figure 12] This is a charge-discharge curve diagram of the sodium ion cathode material of Example 6. [Figure 13] This is the XRD pattern of the sodium ion cathode material of Comparative Example 1. [Figure 14] This is a charge-discharge curve diagram of the sodium ion cathode material of Comparative Example 1. [Figure 15] This is the XRD pattern of the sodium ion cathode material of Comparative Example 2. [Figure 16] This is a charge-discharge curve diagram of the sodium ion cathode material of Comparative Example 2. [Figure 17] This is the XRD pattern of the sodium ion cathode material of Comparative Example 3. [Figure 18] This is a charge-discharge curve diagram of the sodium ion cathode material of Comparative Example 3. [Modes for carrying out the invention]

[0053] As described above, the object of the present invention is to provide a zinc-containing positive electrode material for sodium-ion batteries, a method for producing the same, and its applications.

[0054] Through extensive testing and research, the inventors have discovered the following: By replacing some rare noble metals such as cobalt, nickel, or copper with zinc, the crystal structure of the material can be stabilized. In particular, during the charge-discharge process of sodium-ion batteries, sodium ions are frequently released, but the presence of zinc oxide provides a supporting effect, effectively reducing the collapse of the material structure and providing vacancies for the intercalation of sodium ions, thereby ensuring the rate characteristics of the material. Furthermore, since zinc and oxygen are mostly bonded by ionic bonds, the presence of zinc ions facilitates the capture of more oxygen ions and provides more redox pairs, effectively ensuring the capacity characteristics of the material.

[0055] Furthermore, in this invention, by controlling the structure of the positive electrode material for sodium-ion batteries, the residual alkali (free sodium) in the positive electrode material for sodium-ion batteries is kept at a low level. The positive electrode material for sodium-ion batteries of this invention has a special layered structure, and in its X-ray diffraction pattern, there are six diffraction peaks at a diffraction angle 2θ of 30 to 40°, with a full width at half maximum of 0.04 to 0.4°. The diffraction peaks located around 16° (in this invention, the diffraction angle X° indicates that the diffraction angle is X° ± 1°, for example, 16° indicates 16° ± 1°, i.e., 15 to 17°) and 41° of the diffraction angle 2θ of the material have a full width at half maximum of 0.05 to 0.35°. On the one hand, these special diffraction peaks and full width at half maximum make the structure of the material more stable, ensuring that sodium ions occupy sufficient positions within the material and reducing the amount of free sodium ions on the surface of the material. The residual alkali content of the material is at a relatively low level, and when preparing battery slurry from the material, it can be produced under conditions of less than 40% humidity without the slurry gelling. On the other hand, these special diffraction peaks and full width at half maximum give the material a special lattice plane spacing and transport channels, providing sufficient channels for the transport and diffusion of sodium ions into the material. During the battery charging and discharging process, sodium ions are released smoothly, and sodium-ion batteries have excellent capacity and rate characteristics.

[0056] In one embodiment for carrying out the present invention, a positive electrode material for a sodium-ion battery is provided, the general formula of the positive electrode material is Na 1+a M d Zn x O 2+cwhere -0.40 ≦ a ≦ 0.25, 0.78 < d ≦ 0.93, 0.1 < x ≦ 0.22, and -0.3 < c < 0.3; M is selected from one or more of the elements Mn, Fe, Ni, Co, Al, Zr, Y, Ca, Li, Rb, Cs, W, Ce, Mo, Ba, Ti, Mg, Ta, Nb, V, Sc, Sr, B, and Cu; provided that there is one diffraction peak near a diffraction angle 2θ value of 16°, six diffraction peaks exist at diffraction angle 2θ values of 30 to 40°, and there is one diffraction peak near a diffraction angle 2θ value of 41°.

[0057] In another form for implementing the present invention, a method for manufacturing a positive electrode material for a sodium ion battery including the following steps is provided (there are two manufacturing methods in the present invention, and either manufacturing method can manufacture a positive electrode material for a sodium ion battery). Method 1: (1) Uniformly mix an M source, a Zn source, and a Na source at a molar ratio of M:Zn:Na = (0.78 to 0.93):(0.1 to 0.22):(0.6 to 1.25).

[0058] (2) Next, heat to 750 to 980 °C at a heating rate of 3 to 10 °C / min for firing, the firing time is 8 to 40 hours, cool, and pulverize to obtain a positive electrode material for a sodium ion battery.

[0059] Method 2: (1) Uniformly mix an M source and a Zn source at a certain molar ratio to obtain a precursor.

[0060] (2) Next, uniformly mix it with a Na source (the molar ratio of the M source, Zn source, and Na source is M:Zn:Na = (0.78 to 0.93):(0.1 to 0.22):(0.6 to 1.25)), then heat to 750 to 980 °C at a heating rate of 3 to 10 °C / min for firing, the firing time is 8 to 40 hours, cool, and pulverize to obtain a positive electrode material for a sodium ion battery.

[0061] Unless otherwise specified, the raw materials (sodium source, M source, and Zn source) used in the embodiments of this application are all commercially available products and are common raw materials that can be purchased. The apparatus used in the embodiments of this invention is summarized as follows. 1) Laser particle size distribution analyzer, MSU2000 model, Malvern Panalytical (UK); 2) Automatic specific surface area and pore size distribution analyzer, TriStarII3020, Micromeristics (USA); 3) Powder X-ray diffractometer, X'Pert PRO MPD, Panalytical (Netherlands); 4) ICP-OES iCAP 6300 inductively coupled plasma emission spectrometer; 5) Battery test system, CT-4008-5V50mA-164, Xinwei Xin Energy Technology Co., Ltd.; 6) High-speed vacuum drying oven, KP-BAK-03E-02, Dongguan Kerui Electromechanical Equipment Co., Ltd.; 7) Micro-disc grinder, Suzhou Xiran Industrial Equipment Co., Ltd.; 8) Roller hearth kiln, 36 meters, Huayou Xin Energy Furnace Equipment Co., Ltd.

[0062] The XRD measurement method for the sodium ion cathode material of the embodiment of the present invention is as follows: Measurement conditions: Cu tube, wavelength 1.54060 Å, Be window. In the incident light path, the solar slit is 0.04 rad, the divergence slit is 1 / 2°, the light shield is 10 mm, and the anti-scattering slit is 1°. In the diffraction light path, the anti-scattering slit is 8.0 mm, the solar slit is 0.04 rad, and a large Ni filter is used. The scanning range is 10 to 90°, the scanning step width is 0.013°, the measurement time per step is 30.6 seconds, the voltage is 40 kV, and the current is 40 mA. Powder sample preparation: Using a clean sampling spoon, place the powder into the groove of the glass slide (for large particle samples, it is necessary to polish the powder to less than 50 μm). Place one side of the scraper (more than 20 mm) in contact with the surface of the glass slide, slightly lift the other side (attachment angle less than 10°), and rub the surface of the powder sample with the edge of the scraper to flatten it. Rotate the glass slide 90° and rub again to flatten it. Rub multiple times in both directions until there are no patterns on the surface of the sample. Remove any excess powder around the glass slide and place it in a powder X-ray diffraction analyzer. Sample analysis: Modify the XRD pattern using High-Score Plus software, first determine the background, select peak search to confirm the peaks, repeat the fitting, record the Williamson-Hall plot to calculate the grain size, select the corresponding phase to match the phase and modify the unit cell, and record the unit cell parameters.

[0063] For the measurement of the particle size of the sodium ion cathode material in the embodiments of the present invention, refer to the Chinese National Standard GB / T19077-2016 Particle Size Distribution Laser Diffraction Method. Measurement device: Malvern, Master Size 2000 laser particle size distribution analyzer. Measurement steps: 1 g of powder was weighed, added to 60 mL of pure water, sonicated for 5 minutes, the sample was injected into a sample injector and measured, and the measurement data was recorded. Measurement conditions: The measurement principle is Mie theory, the detection angle is 0~135°, the ultrasonic intensity is 40 kHz 180 W, the particle refractive index is 1.692, the particle absorption coefficient is 1, the sample measurement time is 6 seconds, the number of background measurement snaps is 6000, and the light shielding degree is 8~12%.

[0064] The method for measuring residual alkali in the sodium ion cathode material of the embodiment of the present invention is as follows: Accurately weigh 30 g ± 0.01 g of sample, add the sample to a 250 mL Erlenmeyer flask, add a stirring bar, and add 100 mL of deionized water. Place on a magnetic stirrer, start the apparatus, and stir for 30 minutes. Filter the mixed solution through qualitative filter paper and a funnel. Take out 1 mL of filtrate and add it to a 100 mL beaker, and add a stirring bar. Place the beaker on a magnetic stirrer and add 2 drops of phenolphthalein indicator. Titrate with 0.05 mol / L hydrochloric acid standard solution until the color of the solution changes from red to colorless (V 初 =0), volume V1 of 0.05 mol / L hydrochloric acid standard solution (endpoint 1, V1=V 終1 -V 初 Record the volume of the solution. Add 2 drops of methyl red indicator, and the solution changes color from colorless to yellow. Titrate the solution with 0.05 mol / L hydrochloric acid standard solution until the solution changes color from yellow to orange. Place the beaker in a heating furnace and heat until the solution boils (the solution changes color from orange to yellow). Remove the beaker and allow it to cool to room temperature. Place the beaker again in a magnetic stirrer and titrate the solution with 0.05 mol / L hydrochloric acid standard solution until the solution changes color from yellow to pale red, and record the volume of the 0.05 mol / L hydrochloric acid standard solution (endpoint 2, V2 = V). 終2 -V 終1Record ).

[0065] The formula for calculating the free sodium content is as follows: Na + (wt%) = (c(V1+V2)×10 -3 ×M×100) / m×100% Na2CO3 (wt%) = (c × V2 × 10 -3 ×M1×100) / m×100% NaOH (wt%) = (c × (V1 - V2) × 10 -3 ×M2×100) / m×100% M is the relative atomic mass of sodium, M1 is the relative molecular mass of sodium carbonate, M2 is the relative molecular mass of sodium hydroxide, m is the mass of the sample in grams, V1 is the first titration endpoint in mL, V2 is the second titration endpoint in mL, c is the concentration of the hydrochloric acid standard solution in mol / L, and the 100 in the molecule represents the dilution factor.

[0066] The method for measuring the mass percentage content of elements in the sodium ion cathode material of the embodiment of the present invention is as follows: An ICP-OES iCAP 6300 inductively coupled plasma emission spectrometer is used, the detector has more than 290,000 detection units, the camera temperature of the detector cooling system is less than -35°C, the optical chamber temperature of the optical system is 38±0.1°C, the wavelength range of the optical system is 166~847nm, the plasma observation mode is vertical observation, the plasma observation height is 14mm, the RF power is 1150W, the frequency is 27.12MHz, the auxiliary gas flow rate of the sampling system is 0.5L / min, the atomizing gas flow rate of the sampling system is 0.6L / min, and the pump speed is 50rpm. Measurement of trace amounts: Accurately weigh 0.2000-0.2100g of sample and place it in a 50mL quartz beaker. Add 10mL of 1:1 aqua regia, place a watch glass over it, and heat in a furnace until completely dissolved. Transfer to a 50mL volumetric flask, adjust to the desired volume, shake evenly, load, measure, and record the data. Measurement of main volume: Take 1mL of the evenly shaken solution and place it in a 100mL volumetric flask. Adjust to the desired volume of 100mL and shake evenly. Load, measure, and record the data.

[0067] The sodium-ion battery of the present invention is composed of electrodes, an electrolyte, a separator, and an aluminum laminate film. Specifically, the electrodes include a positive electrode and a negative electrode. The positive electrode is manufactured from materials such as a positive electrode current collector, a positive electrode active material coated on the positive electrode current collector, an adhesive, and a conductive additive, and the positive electrode active material is the positive electrode material of the present invention. The negative electrode is manufactured from materials such as a current collector, a negative electrode active material coated on the current collector, an adhesive, and a conductive additive. The separator is a PP / PE film commonly used in this field to isolate the positive and negative electrodes from each other. The aluminum laminate film is a coating material for the positive electrode, negative electrode, separator, and electrolyte.

[0068] The adhesive of the present invention is mainly used to improve the adhesion between positive electrode active material particles and between positive electrode active material particles and current collectors. The adhesive of the present invention may be a commercially available adhesive that is commonly used in the art. Specifically, the adhesive may be selected from polyvinyl alcohol, carboxymethylcellulose, hydroxypropylcellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene oxide-containing polymer, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, poly(vinylidene fluoride), polyethylene, polypropylene, styrene-butadiene rubber, acrylic acid (esterified) styrene-butadiene rubber, epoxy resin, nylon, or a combination thereof.

[0069] The conductive additive of the present invention may be a commercially available conductive additive commonly used in the art. Specifically, the conductive additive may be selected from carbon-based materials (e.g., natural graphite, artificial graphite, carbon black, acetylene black, Ketjenblack, or carbon fibers), metallic materials (e.g., including metal powders or metal fibers such as copper, nickel, aluminum, and silver), conductive polymers (e.g., polyphenylene derivatives), or combinations thereof.

[0070] In the following embodiments, the specific procedure for manufacturing a sodium-ion button cell using the positive electrode material produced in the present invention is as follows. Manufacturing of the positive electrode: The positive electrode material manufactured in this invention, polyvinylidene fluoride (PVDF) adhesive, and conductive carbon black (SP) are thoroughly mixed in a weight ratio of 7:2:1, stirred to form a uniform slurry, coated onto an aluminum foil current collector, dried, and pressed to obtain an electrode plate. After pressing, the positive electrode plate is pressed, weighed, and baked. Next, the battery is assembled in a vacuum glove box. First, the base of the button battery is placed, followed by nickel foam (2.5 mm) and a negative electrode metallic sodium sheet (manufacturer: Shenzhen Youyan Technology Co., Ltd.). 0.5 g of electrolyte is injected in an environment with a relative humidity of less than 1.5%. The electrolyte is a mixed solvent of ethylene carbonate (EC), diethyl carbonate (DEC), and dimethyl carbonate (DMC) in a mass ratio of 1:1:1. The electrolyte is a 1 mol / L lithium hexafluoride phosphate solution. A separator and positive electrode plate are then placed, followed by the button battery cover and sealing. The model number of the button battery is CR2430.

[0071] In this invention, the unit of the full width at half maximum of the diffraction peak is the same as the unit of the diffraction angle 2θ. The present invention will be described in more detail below with reference to the drawings, using specific embodiments.

[0072] (Example 1) Sodium carbonate, manganese carbonate, nickel carbonate, ferric oxide, and zinc oxide are weighed in the corresponding amounts according to the stoichiometric molar ratio Na:Mn:Ni:Fe:Zn = 0.87:0.33:0.23:0.29:0.15. Then, the mixture is ball-milled at 40 Hz for 10 minutes to ensure uniform mixing. The uniformly mixed raw materials are heated to 960°C in an air atmosphere at a heating rate of 5°C / min and kept at a constant temperature for 12 hours. Then, they are allowed to cool naturally, pulverized, and sieved to obtain a material with the molecular formula Na 0.87 Ni 0.23 Mn 0.33 Zn 0.15 Fe 0.29 Obtain a positive electrode material that is O2.

[0073] Figure 1 shows the XRD pattern of the cathode material of this embodiment. As can be seen from the figure, the diffraction peak with a diffraction angle 2θ of 16.5257° has a full width at half maximum (FWHM) of 0.128°, and this diffraction peak is the second strongest peak. The diffraction peak with a diffraction angle 2θ of 31.774° has a FWHM of 0.076°, the diffraction peak with a diffraction angle 2θ of 33.439° has a FWHM of 0.148°, and the diffraction peak with a diffraction angle 2θ of 34.453° has a FWHM of 0.148°. The FWHM is 0.083°, the FWHM of the diffraction peak with a diffraction angle 2θ of 35.208° is 0.154°, the FWHM of the diffraction peak with a diffraction angle 2θ of 36.263° is 0.074°, the FWHM of the diffraction peak with a diffraction angle 2θ of 36.5543° is 0.135°, and the FWHM of the diffraction peak with a diffraction angle 2θ of 41.573° is 0.1121°, making this diffraction peak the strongest peak. The ratio of peak intensity between the diffraction peak with a diffraction angle 2θ around 31.8° and the diffraction peak with a diffraction angle 2θ around 34.4° is 1.6:1, and the ratio of peak intensity between the diffraction peak with a diffraction angle 2θ around 36.3° and the diffraction peak with a diffraction angle 2θ around 34.4° is 2.7:1.

[0074] The particle size and specific surface area of ​​the cathode material were measured, and the particle size D50 was 4.9 μm, and the BET was 1.2 μm. 2 The value is / g. The residual alkali content on the surface is 1.25%. Table 1 summarizes the diffraction peaks and full width at half maximum, particle size D50, specific surface area, and residual alkali content on the surface of the positive electrode material in the XRD pattern. A button cell was manufactured using the said positive electrode material, and the capacity and rate were measured. See Table 1 for details of the measurement data, and Figure 2 shows the 0.1C / 0.1C charge / discharge curves under conditions of 4.0~2.0V.

[0075] (Example 2) Sodium carbonate, manganese dioxide, nickel oxide, ferric oxide, and zinc oxide are weighed in corresponding amounts according to the stoichiometric molar ratio Na:Mn:Ni:Fe:Zn = 0.80:0.30:0.22:0.27:0.21. Then, the mixture is ball-milled at 35 Hz for 20 minutes to ensure uniform mixing. The uniformly mixed raw materials are heated to 900°C in an air atmosphere at a heating rate of 3°C / min and kept at a constant temperature for 16 hours. Then, they are allowed to cool naturally, pulverized, and sieved to obtain a material with the molecular formula Na 0.8 Ni 0.22 Mn 0.3 Zn 0.21 Fe 0.27 Obtain a positive electrode material that is O2.

[0076] Figure 3 shows the XRD pattern of the cathode material of this embodiment. As can be seen from the figure, the diffraction peak with a diffraction angle 2θ of 16.52° has a full width at half maximum (FWHM) of 0.1252°, and this diffraction peak is the second strongest peak. The diffraction peak with a diffraction angle 2θ of 31.782° has a FWHM of 0.064°, the diffraction peak with a diffraction angle 2θ of 33.423° has a FWHM of 0.137°, and the diffraction peak with a diffraction angle 2θ of 34.444° is The full width at half maximum (FWHM) is 0.08°. The FWHM of the diffraction peak with a diffraction angle 2θ of 35.232° is 0.145°, the FWHM of the diffraction peak with a diffraction angle 2θ of 36.274° is 0.068°, the FWHM of the diffraction peak with a diffraction angle 2θ of 36.575° is 0.135°, and the FWHM of the diffraction peak with a diffraction angle 2θ of 41.587° is 0.1102°, making this diffraction peak the strongest. The ratio of peak intensity between the diffraction peak with a diffraction angle 2θ around 31.8° and the diffraction peak with a diffraction angle 2θ around 34.4° is 1.8:1, and the ratio of peak intensity between the diffraction peak with a diffraction angle 2θ around 36.3° and the diffraction peak with a diffraction angle 2θ around 34.4° is 2.8:1.

[0077] The particle size and specific surface area of ​​the cathode material were measured, and the particle size D50 was found to be 5.0 μm, and the BET was 0.97 m². 2The value is / g. The residual alkali content on the surface is 0.78%. Table 1 summarizes the diffraction peaks and full width at half maximum, particle size D50, specific surface area, and residual alkali content on the surface of the positive electrode material in the XRD pattern. A button cell was manufactured using the positive electrode material, and the capacity and rate were measured. See Table 1 for details of the measurement data, and Figure 4 shows the 0.1C / 0.1C charge / discharge curves under conditions of 4.0~2.0V.

[0078] (Example 3) Sodium carbonate, dimanganese trioxide, nickel oxide, ferrous oxalate, zinc oxide, and calcium oxide are weighed in the corresponding amounts according to the stoichiometric molar ratio Na:Mn:Ni:Fe:Zn:Ca = 0.76:0.29:0.21:0.27:0.21:0.02. Then, the mixture is ball-milled at 30 Hz for 30 minutes to ensure uniform mixing. The uniformly mixed raw materials are heated to 860°C in an air atmosphere at a heating rate of 7°C / min and kept at a constant temperature for 20 hours. Then, they are allowed to cool naturally, pulverized, and sieved to obtain a material with the molecular formula Na 0.76 Ni 0.21 Mn 0.29 Zn 0.21 Fe 0.27 Ca 0.02 Obtain a positive electrode material that is O2.

[0079] Figure 5 shows the XRD pattern of the cathode material of this embodiment. As can be seen from the figure, the diffraction peak with a diffraction angle 2θ of 16.5456° has a full width at half maximum (FWHM) of 0.13°, and this diffraction peak is the second strongest peak. The diffraction peak with a diffraction angle 2θ of 31.789° has a FWHM of 0.074°, the diffraction peak with a diffraction angle 2θ of 33.445° has a FWHM of 0.163°, and the diffraction peak with a diffraction angle 2θ of 34.463° has a FWHM of 0.163°. The width FWHM is 0.077°, the FWHM of the diffraction peak with a diffraction angle 2θ of 35.244° is 0.16°, the FWHM of the diffraction peak with a diffraction angle 2θ of 36.2902° is 0.073°, the FWHM of the diffraction peak with a diffraction angle 2θ of 36.5856° is 0.143°, and the FWHM of the diffraction peak with a diffraction angle 2θ of 41.5986° is 0.1092°, making this diffraction peak the strongest peak. The ratio of peak intensity between the diffraction peak with a diffraction angle 2θ around 31.8° and the diffraction peak with a diffraction angle 2θ around 34.4° is 1.6:1, and the ratio of peak intensity between the diffraction peak with a diffraction angle 2θ around 36.3° and the diffraction peak with a diffraction angle 2θ around 34.4° is 2.7:1.

[0080] The particle size and specific surface area of ​​the cathode material were measured, and the particle size D50 was found to be 5.3 μm, and the BET was 0.94 μm. 2 The value is / g, and the residual alkali content on its surface is 2.28%. Table 1 summarizes the diffraction peaks and full width at half maximum, particle size D50, specific surface area, and residual alkali content on the surface of the positive electrode material in its XRD pattern. A button cell was manufactured using this positive electrode material, and its capacity and rate were measured. See Table 1 for details of the measurement data, and Figure 6 shows the 0.1C / 0.1C charge / discharge curves under conditions of 4.0~2.0V.

[0081] (Example 4) Sodium nitrate, dimanganese trioxide, nickel oxide, ferrous oxalate, zinc oxide, and diboron trioxide are weighed in the corresponding amounts according to the stoichiometric molar ratio Na:Mn:Ni:Fe:Zn:B = 0.8:0.294:0.21:0.28:0.21:0.006. Then, the mixture is ball-milled at 25 Hz for 45 minutes to ensure uniform mixing. The uniformly mixed raw materials are heated to 890°C in an air atmosphere at a heating rate of 10°C / min and kept at a constant temperature for 24 hours. Then, they are allowed to cool naturally, pulverized, and sieved to obtain a material with the molecular formula Na 0.8 Ni 0.21 Mn 0.294 Zn 0.21 Fe 0.28 B 0.006 Obtain a positive electrode material that is O2.

[0082] Figure 7 shows the XRD pattern of the cathode material of this embodiment. As can be seen from the figure, the full width at half maximum (FWHM) of the diffraction peak with a diffraction angle 2θ of 16.58° is 0.1205°, and this diffraction peak is the second strongest peak. The full width at half maximum (FWHM) of the diffraction peak with a diffraction angle 2θ of 31.786° is 0.106°, the full width at half maximum (FWHM) of the diffraction peak with a diffraction angle 2θ of 33.5115° is 0.147°, and the full width at half maximum (FWHM) of the diffraction peak with a diffraction angle 2θ of 34.461° is 0.147°. The width FWHM is 0.078°, the FWHM of the diffraction peak with a diffraction angle 2θ of 35.176° is 0.147°, the FWHM of the diffraction peak with a diffraction angle 2θ of 36.2824° is 0.082°, the FWHM of the diffraction peak with a diffraction angle 2θ of 36.5282° is 0.134°, and the FWHM of the diffraction peak with a diffraction angle 2θ of 41.5678° is 0.1078°, making this diffraction peak the strongest peak. The ratio of peak intensity between the diffraction peak with a diffraction angle 2θ around 31.8° and the diffraction peak with a diffraction angle 2θ around 34.4° is 1.2:1, and the ratio of peak intensity between the diffraction peak with a diffraction angle 2θ around 36.3° and the diffraction peak with a diffraction angle 2θ around 34.4° is 2.5:1.

[0083] The particle size and specific surface area of ​​the cathode material were measured, and the particle size D50 was found to be 7.5 μm, and the BET was 0.43 μm. 2The value is / g, and the residual alkali content on its surface is 2.21%. Table 1 summarizes the diffraction peaks and full width at half maximum, particle size D50, specific surface area, and residual alkali content on the surface of the positive electrode material in its XRD pattern. A button cell was manufactured using this positive electrode material, and its capacity and rate were measured. See Table 1 for details of the measurement data, and Figure 8 shows the 0.1C / 0.1C charge / discharge curves under conditions of 4.0~2.0V.

[0084] (Example 5) Manganese carbonate, nickel carbonate, ferrous oxalate, zinc oxide, and calcium oxide are weighed in the corresponding amounts according to the stoichiometric molar ratio Mn:Ni:Fe:Zn:Ca = 0.28:0.3:0.27:0.13:0.02. These are then added to a sander and polished for 60 minutes to obtain a wet precursor. The wet precursor is spray-dried to obtain a precursor. The precursor and sodium chloride are uniformly mixed in the stoichiometric ratio (Na:Mn:Ni:Fe:Zn:Ca = 1.1:0.28:0.3:0.27:0.13:0.02). The uniformly mixed raw materials are heated to 900°C at a heating rate of 6°C / min in an air atmosphere and kept at a constant temperature for 14 hours. Then, they are allowed to cool naturally, pulverized, and sieved to obtain a molecule with the molecular formula Na 1.1 Ni 0.3 Mn 0.28 Zn 0.13 Fe 0.27 Ca 0.02 Obtain a positive electrode material that is O2.

[0085] Figure 9 shows the XRD pattern of the cathode material of this embodiment. As can be seen from the figure, the diffraction peak with a diffraction angle 2θ of 16.559° has a full width at half maximum (FWHM) of 0.1263°, and this diffraction peak is the second strongest peak. The diffraction peak with a diffraction angle 2θ of 31.772° has a FWHM of 0.091°, the diffraction peak with a diffraction angle 2θ of 33.49° has a FWHM of 0.171°, and the diffraction peak with a diffraction angle 2θ of 34.44° has a FWHM of 0.171°. The width FWHM is 0.083°, the FWHM of the diffraction peak with a diffraction angle 2θ of 35.159° is 0.147°, the FWHM of the diffraction peak with a diffraction angle 2θ of 36.264° is 0.088°, the FWHM of the diffraction peak with a diffraction angle 2θ of 36.5109° is 0.135°, and the FWHM of the diffraction peak with a diffraction angle 2θ of 41.5515° is 0.1077°, making this diffraction peak the strongest peak. The ratio of peak intensity between the diffraction peak with a diffraction angle 2θ around 31.8° and the diffraction peak with a diffraction angle 2θ around 34.4° is 1.4:1, and the ratio of peak intensity between the diffraction peak with a diffraction angle 2θ around 36.3° and the diffraction peak with a diffraction angle 2θ around 34.4° is 2.6:1.

[0086] The particle size and specific surface area of ​​the cathode material were measured, and the particle size D50 was found to be 4.9 μm, and the BET was 0.69 μm. 2 The value is / g. The residual alkali content on the surface is 2.95%. Table 2 summarizes the diffraction peaks and full width at half maximum, particle size D50, specific surface area, and residual alkali content on the surface of the positive electrode material in the XRD pattern. A button cell was manufactured using the said positive electrode material, and the capacity and rate were measured. See Table 2 for details of the measurement data, and Figure 10 shows the 0.1C / 0.1C charge / discharge curves under conditions of 4.0~2.0V.

[0087] (Example 6) Manganese carbonate, nickel carbonate, ferrous oxalate, zinc oxide, and copper sulfate are weighed in corresponding amounts according to the stoichiometric molar ratio Mn:Ni:Fe:Zn:Cu=0.3:0.31:0.27:0.1:0.02. These are then added to a sander and polished for 45 minutes to obtain a wet precursor. The wet precursor is spray-dried to obtain a precursor. The precursor and sodium chloride (Na:Mn:Ni:Fe:Zn:Cu=1.15:0.3:0.31:0.27:0.1:0.04) are uniformly mixed in stoichiometric ratios. The uniformly mixed raw materials are heated to 880°C in an air atmosphere at a heating rate of 5°C / min and kept at a constant temperature for 15 hours. Then, they are allowed to cool naturally, pulverized, and sieved to obtain a molecule with the molecular formula Na 1.15 Ni 0.31 Mn 0.3 Zn 0.1 Fe 0.27 Cu 0.02 Obtain a positive electrode material that is O2.

[0088] Figure 11 shows the XRD pattern of the cathode material of this embodiment. As can be seen from the figure, the diffraction peak with a diffraction angle 2θ of 16.4554° has a full width at half maximum (FWHM) of 0.132°, and this diffraction peak is the second strongest peak. The diffraction peak with a diffraction angle 2θ of 31.718° has a FWHM of 0.133°, the diffraction peak with a diffraction angle 2θ of 33.338° has a FWHM of 0.158°, and the diffraction peak with a diffraction angle 2θ of 34.411° is The full width at half maximum (FWHM) is 0.111°. The FWHM of the diffraction peak with a diffraction angle 2θ of 35.205° is 0.169°, the FWHM of the diffraction peak with a diffraction angle 2θ of 36.221° is 0.133°, the FWHM of the diffraction peak with a diffraction angle 2θ of 36.5471° is 0.15°, and the FWHM of the diffraction peak with a diffraction angle 2θ of 41.5489° is 0.1221°, making this diffraction peak the strongest. The ratio of peak intensity between the diffraction peak with a diffraction angle 2θ around 31.8° and the diffraction peak with a diffraction angle 2θ around 34.4° is 1.43:1, and the ratio of peak intensity between the diffraction peak with a diffraction angle 2θ around 36.3° and the diffraction peak with a diffraction angle 2θ around 34.4° is 2.2:1.

[0089] The particle size and specific surface area of the positive electrode material were measured. The particle size D50 was 11.1 μm, and the BET was 0.79 m 2 / g. The content of residual alkali on its surface was 3.15%. The diffraction peaks, half-widths, particle size D50, specific surface area, and residual alkali amount on the surface in the XRD pattern of the positive electrode material are summarized in Table 2. A button battery was manufactured using the positive electrode material, and the capacity and rate were measured. For the details of the measurement data, refer to Table 2. The charge-discharge curve diagram of 0.1C / 0.1C under the conditions of 4.0~2.0V is as shown in Fig. 12.

[0090] (Comparative Example 1) Compared with Example 1, zinc oxide was changed to copper oxide, and the rest of the manufacturing method was the same as that of Example 1. The molecular formula is Na 0.87 Ni 0.23 Mn 0.33 Cu 0.15 Fe 0.29 O2 is used to produce the positive electrode material.

[0091] Fig. 13 shows the XRD pattern of the positive electrode material of this example. As can be seen from the figure, the half-width FWHM of the diffraction peak with a diffraction angle 2θ of 16.5° is 0.121°, and this diffraction peak is the second strongest peak. The half-width FWHM of the diffraction peak with a diffraction angle 2θ of 33.4° is 0.149°, the half-width FWHM of the diffraction peak with a diffraction angle 2θ of 35.2° is 0.124°, the half-width FWHM of the diffraction peak with a diffraction angle 2θ of 36.6° is 0.115°, the half-width FWHM of the diffraction peak with a diffraction angle 2θ of 38.7° is 0.18°, and the half-width FWHM of the diffraction peak with a diffraction angle 2θ of 41.6° is 0.089°, and this diffraction peak is the strongest peak.

[0092] The particle size and specific surface area of the positive electrode material were measured. The particle size D50 was 7.1 μm, and the BET was 0.6 m 2It is / g, and the content of residual alkali on its surface is 3.8%. The diffraction peaks, half-value widths, particle size D50, specific surface area, and residual alkali amount on the surface in the XRD pattern of the positive electrode material are summarized in Table 2. Using the said positive electrode material to manufacture a button battery, measuring the capacity and rate, for the details of the measurement data, refer to Table 2. The charge-discharge curve diagram of 0.1C / 0.1C under the conditions of 4.0~2.0V is as shown in Fig. 14.

[0093] (Comparative Example 2) Weigh corresponding amounts of sodium carbonate, manganese sesquioxide, nickel oxide, ferrous oxalate, and calcium oxide in a stoichiometric molar ratio of Na:Mn:Ni:Fe:Ca = 0.79:0.37:0.28:0.33:0.02. Next, perform ball milling at 30 Hz and mix uniformly for 30 minutes. Heat the uniformly mixed raw materials to 860 °C at a heating rate of 7 °C / min in an air atmosphere, hold at a constant temperature for 20 hours, then cool naturally, pulverize, and screen to obtain a positive electrode material with a molecular formula of Na 0.79 Ni 0.28 Mn 0.37 Fe 0.33 Ca 0.02 O2.

[0094] Fig. 15 shows the XRD pattern of the positive electrode material of this example. As can be seen from the figure, the half-value width FWHM of the diffraction peak with a diffraction angle 2θ of 16.5° is 0.212°, and this diffraction peak is the second strongest peak. The half-value width FWHM of the diffraction peak with a diffraction angle 2θ of 33.5° is 0.2°, the half-value width FWHM of the diffraction peak with a diffraction angle 2θ of 34.2° is 0.31°, the half-value width FWHM of the diffraction peak with a diffraction angle 2θ of 35.2° is 0.203°, the half-value width FWHM of the diffraction peak with a diffraction angle 2θ of 41.5° is 0.183°, and this diffraction peak is the strongest peak.

[0095] Measure the particle size and specific surface area of the said positive electrode material. The particle size D50 is 9.5 μm, and the BET is 0.4 m 2The value is / g, and the residual alkali content on its surface is 4.68%. Table 2 summarizes the diffraction peaks and full width at half maximum, particle size D50, specific surface area, and residual alkali content on the surface of the positive electrode material in its XRD pattern. A button cell was manufactured using this positive electrode material, and its capacity and rate were measured. See Table 2 for details of the measurement data, and Figure 16 shows the 0.1C / 0.1C charge / discharge curves under conditions of 4.0~2.0V.

[0096] (Comparative Example 3) Manganese carbonate, nickel carbonate, ferrous oxalate, zinc oxide, and copper sulfate are weighed in the corresponding amounts according to the stoichiometric molar ratio Mn:Ni:Fe:Zn:Cu=0.26:0.21:0.24:0.25:0.04. These are then added to a sander and polished for 45 minutes to obtain a wet precursor. The wet precursor is spray-dried to obtain a precursor. The precursor and sodium chloride (Na:Mn:Ni:Fe:Zn:Cu=0.79:0.26:0.21:0.24:0.25:0.04) are uniformly mixed in stoichiometric ratios. The uniformly mixed raw materials are heated to 880°C in an air atmosphere at a heating rate of 5°C / min and kept at a constant temperature for 15 hours. Then, they are allowed to cool naturally, pulverized, and sieved to obtain a molecule with the molecular formula Na 0.79 Ni 0.21 Mn 0.26 Zn 0.25 Fe 0.24 Cu 0.04 We manufacture the positive electrode material, which is O2.

[0097] Figure 17 shows the XRD pattern of the cathode material of this embodiment. As can be seen from the figure, the diffraction peak with a diffraction angle 2θ of 16.432° has a full width at half maximum (FWHM) of 0.143°, and this diffraction peak is the second strongest peak. The diffraction peak with a diffraction angle 2θ of 31.695° has a FWHM of 0.098°, the diffraction peak with a diffraction angle 2θ of 32.26° has a FWHM of 0.19°, the diffraction peak with a diffraction angle 2θ of 33.333° has a FWHM of 0.169°, and the diffraction peak with a diffraction angle 2θ of 34.362° has a FWHM of 0.169°. The width FWHM is 0.089°, the FWHM of the diffraction peak with diffraction angle 2θ of 35.145° is 0.143°, the FWHM of the diffraction peak with diffraction angle 2θ of 36.187° is 0.089°, the FWHM of the diffraction peak with diffraction angle 2θ of 36.4908° is 0.148°, the FWHM of the diffraction peak with diffraction angle 2θ of 37.833° is 0.06°, and the FWHM of the diffraction peak with diffraction angle 2θ of 41.4908° is 0.1213°, making this diffraction peak the strongest peak. The ratio of the peak intensities of diffraction peaks with a diffraction angle 2θ of approximately 31.8° to those with a diffraction angle 2θ of approximately 34.4° is 1.3:1, and the ratio of the peak intensities of diffraction peaks with a diffraction angle 2θ of approximately 36.3° to those with a diffraction angle 2θ of approximately 34.4° is 3.88:1.

[0098] The particle size and specific surface area of ​​the cathode material were measured, and the particle size D50 was found to be 6.9 μm, and the BET was 0.67 μm. 2 The value is / g. The residual alkali content on the surface is 4.13%. Table 3 summarizes the diffraction peaks and full width at half maximum, particle size D50, specific surface area, and residual alkali content on the surface of the positive electrode material in the XRD pattern. A button cell was manufactured using the positive electrode material, and the capacity and rate were measured. See Table 3 for details of the measurement data, and Figure 18 shows the 0.1C / 0.1C charge / discharge curves under conditions of 4.0~2.0V.

[0099] [Table 1]

[0100] [Table 2]

[0101] [Table 3]

[0102] [Table 4]

[0103] As can be seen from the table above, the zinc content of the cathode materials manufactured in Examples 1 to 6 is within the scope of the claims of the present invention. In the XRD pattern of the cathode materials, there are six diffraction peaks at a diffraction angle 2θ value of 30 to 40°, and the full width at half maximum of the diffraction peaks is 0.04 to 0.18°. The structure of the cathode material is stable, the discharge capacity at 0.1C is relatively high, and the rate characteristics are excellent. Furthermore, the residual alkali content of the cathode materials manufactured in Examples 1 to 6 is relatively low, and can be kept within 3.5%, and in particular, the residual alkali content in Examples 1 to 4 is kept within 2.3%.

[0104] Comparative Example 1 employs the same manufacturing method as Example 1, the only difference being the substitution of zinc with copper. In its XRD pattern, four diffraction peaks are present at diffraction angle 2θ values ​​of 30-40°. Furthermore, the residual alkali content of the cathode material produced in Comparative Example 1 is much higher than that of Example 1, and the volume of the material is also much lower than that of Example 1. The rate characteristics of the material are inferior to those of Example 1.

[0105] Comparative Example 2 employs the same manufacturing method as Example 3, the only difference being the absence of new elements. In its XRD pattern, three diffraction peaks are present at diffraction angle 2θ values ​​of 30-40°. The residual alkali content of the cathode material produced in Comparative Example 2 is much higher than that of Example 3. The Ni element content of the material is relatively high, and the theoretical capacity should also be high. However, the actual capacity is much lower than that of Example 3, and the rate characteristics of the material are inferior to those of Example 3.

[0106] Comparative Example 3 employs the same manufacturing method as Example 6, the only difference being that the amount of zinc added exceeds the claims of the present invention. In the XRD pattern of the cathode material, eight diffraction peaks are present at diffraction angle 2θ values ​​of 30-40°, which is two more unwanted peaks compared to Example 6. This suggests that the excessive zinc content causes some of the zinc to form new solid solutions with other elements, resulting in a high residual alkali content, low capacity, and poor rate characteristics in the material.

[0107] As can be seen from the above data, assuming that replacing some rare precious metals (e.g., nickel) with zinc does not affect the material's properties, when zinc is added to improve the structural stability of a material, on the one hand, zinc and oxygen are mostly bonded by ionic bonds, and the presence of zinc ions makes it easier to capture more oxygen ions and provide more redox pairs, effectively guaranteeing the material's capacity properties. On the other hand, the presence of zinc oxide can stabilize the material's crystal structure, and especially in the charge-discharge process of sodium-ion batteries, sodium ions are frequently released, but the presence of zinc oxide acts as a support, effectively reducing the collapse of the material structure, providing vacancies for sodium ion intercalation, and guaranteeing the material's rate properties.

[0108] The applicant claims that what is described above is merely a form for implementing the present invention, and the claims of the present invention are not limited thereto. It should be self - evident to those skilled in the art that any changes or substitutions that are readily conceivable within the technical scope disclosed in the present invention should fall within the scope of the claims and the disclosure scope of the present invention.

[0109] (Appendix) (Appendix 1) A cathode material for a sodium - ion battery, The general formula of the cathode material is Na 1+a M d Zn x O 2+c where - 0.40 ≤ a ≤ 0.25, 0.78 < d ≤ 0.93, 0.1 < x ≤ 0.22, - 0.3 < c < 0.3, M is selected from one or more of the elements Mn, Fe, Ni, Co, Al, Zr, Y, Ca, Li, Rb, Cs, W, Ce, Mo, Ba, Ti, Mg, Ta, Nb, V, Sc, Sr, B, and Cu. However, there is one diffraction peak near 16° of the diffraction angle 2θ value, at least five diffraction peaks exist at 30 - 40° of the diffraction angle 2θ value, and there is one diffraction peak near 41° of the diffraction angle 2θ value. <000055​​​​​​​​​​​​​​​​​​​​​​​​where 0.1 < x ≤ 0.22, 0.0 < b ≤ 0.06, -0.40 ≤ a ≤ 0.25, -0.3 < c < 0.3, y = 1 - x, and A and B are each selected from one or more of the elements Mn, Fe, Ni, Co, Al, Zr, Y, Ca, Li, Rb, Cs, W, Ce, Mo, Ba, Ti, Mg, Ta, Nb, V, Sc, Sr, B, and Cu, and A and B may be the same or different. Preferably, the element B in the positive electrode material for a sodium ion battery is selected from one or more of Mn, Fe, Ni, and Co. More preferably, the general formula of the positive electrode material for a sodium ion battery is Na 1+a Ni y Mn z Fe 1-x-y-z-b Zn x A b O 2+c where 0.15 ≤ y ≤ 0.35, 0.20 ≤ z ≤ 0.38, - .40 ≤ a ≤ 0.25, 0.0 < b ≤ 0.06, -0.3 < c < 0.3, and 0.1 < x ≤ 0.22. The positive electrode material for a sodium ion battery according to Supplementary Note 1, characterized in that.

[0111] (Supplementary Note 3) The mass percentage content of zinc element in the positive electrode material for a sodium ion battery is 5. ~ 20.0%. Preferably, the mass percentage content of zinc element in the positive electrode material for a sodium ion battery is 5.0 ~ 15.0%. More preferably, the powder X-ray diffraction pattern of the positive electrode material for a sodium ion battery indicates an α-NaFeO4 type layered structure. The positive electrode material for a sodium ion battery according to Supplementary Note 1, characterized in that.

[0112] (Supplementary Note 4) In the powder X-ray diffraction pattern of the positive electrode material for a sodium ion battery, the half-value width of the diffraction peak with a 2θ value of 30 ~ 40° is 0.04 ~ 0.4°, preferably 0.04 ~ 0.30°, and more preferably 0.04 ~ 0.25°. And / or, a second strongest peak exists near 16° of 2θ, a first strongest peak exists near 41°, preferably a second strongest peak exists near 16.5° of 2θ, a first strongest peak exists near 41.6°, and / or, the full width at half maximum of the diffraction peaks where 2θ is near 16° and 41° is 0.05 to 0.35°, preferably 0.05 to 0.30°, and more preferably 0.05 to 0.25°. The positive electrode material for sodium-ion batteries as described in Appendix 1, characterized by the features described herein.

[0113] (Note 5) In the powder X-ray diffraction pattern of the aforementioned positive electrode material for sodium-ion batteries, six diffraction peaks are present in the 2θ range of 30-40°, with their respective 2θ values ​​being approximately 32°, 33°, 34°, 35°, and 36°. Preferably, the 2θ values ​​of the six diffraction peaks are around 31.8°, 33.4°, 34.4°, 35.2°, 36.3°, and 36.6°, respectively. A positive electrode material for a sodium-ion battery as described in any one of the appendices 1 to 4, characterized by the features described herein.

[0114] (Note 6) In the powder X-ray diffraction pattern (XRD) of the positive electrode material for the sodium-ion battery, the full width at half maximum (FWHM) of the diffraction peaks with a diffraction angle 2θ of approximately 31.8° is 0.06 to 0.25°, the FWHM of the diffraction peaks with a diffraction angle 2θ of approximately 34.4° is 0.07 to 0.25°, and the FWHM of the diffraction peaks with a diffraction angle 2θ of approximately 36.3° is 0.06 to 0.25°. Preferably, the ratio of the peak intensities of the diffraction peak with a diffraction angle 2θ around 31.8° to the diffraction peak with a diffraction angle 2θ around 34.4° is (1-2):1, preferably (1.2-1.8):1, more preferably (1.3-1.7):1, and / or The ratio of the peak intensities of diffraction peaks with a diffraction angle 2θ around 36.3° to diffraction peaks with a diffraction angle 2θ around 34.4° is (2-3):1, preferably (2.2-2.8):1, and more preferably (2.2-2.7):1. A positive electrode material for a sodium-ion battery as described in any one of the appendices 1 to 4, characterized by the features described herein.

[0115] (Note 7) In the powder X-ray diffraction pattern (XRD) of the positive electrode material for the sodium-ion battery, The full width at half maximum (FWHM) of a diffraction peak has one or more of the following characteristics: (1) The full width at half maximum (FWHM) of the diffraction peak with a diffraction angle 2θ around 16.5° is 0.08 to 0.25°. (2) The full width at half maximum (FWHM) of the diffraction peak with a diffraction angle 2θ of approximately 33.4° is 0.08 to 0.23°. (3) The full width at half maximum (FWHM) of the diffraction peak with a diffraction angle 2θ around 35.2° is 0.07 to 0.22°. (4) The full width at half maximum (FWHM) of the diffraction peak with a diffraction angle 2θ around 36.6° is 0.08 to 0.20°, and (5) The full width at half maximum (FWHM) of the diffraction peak with a diffraction angle 2θ around 41.6° is 0.06 to 0.20°. A sodium ion cathode material characterized by any one of the appendices 1 to 4.

[0116] (Note 8) The specific surface area of ​​the aforementioned positive electrode material for sodium-ion batteries is 0.25 to 1.5 m². 2 The value is / g, preferably 0.69 to 1.5m 2 The particle size is / g, and / or the particle size D50 of the positive electrode material for the sodium-ion battery is 2 to 15 μm, preferably 5.3 to 15 μm. A positive electrode material for a sodium-ion battery as described in any one of the appendices 1 to 4, characterized by the features described herein.

[0117] (Note 9) The mass percentage content of residual alkali in the positive electrode material for the sodium-ion battery is 3.15% or less, preferably 0.7 to 3.15%. A positive electrode material for a sodium-ion battery as described in any one of the appendices 1 to 4, characterized by the features described herein.

[0118] (Note 10) A precursor is obtained by mixing the M source and the Zn source in a fixed ratio, and then uniformly mixing it with the Na source, or after uniformly mixing the M source, Zn source and Na source, The process includes the steps of firing at a temperature of 750-980°C and / or firing for 8-40 hours, followed by cooling and pulverization to obtain a positive electrode material for a sodium-ion battery. A method for producing a positive electrode material for a sodium-ion battery, characterized by any one of the appendices 1 to 4.

[0119] (Note 11) The firing temperature is 880 to 960°C, and / or the firing time is 15 to 25 hours, preferably the firing temperature is raised at a heating rate of 3 to 10°C / minute to perform constant-temperature firing. A method for producing a positive electrode material for a sodium-ion battery as described in Appendix 10, characterized by the above.

[0120] (Note 12) In the aforementioned grinding, a disc grinder is used, preferably with a distance between discs of 0 to 2 mm and / or a rotational speed of 500 to 3000 revolutions per minute. A method for producing a positive electrode material for a sodium-ion battery as described in Appendix 10, characterized by the above.

[0121] (Note 13) The sodium source is selected from one or more of the following: sodium hydroxide, sodium carbonate, sodium nitrate, sodium oxalate, sodium chloride, sodium fluoride, and sodium acetate. A method for producing a positive electrode material for a sodium-ion battery as described in Appendix 10, characterized by the above.

[0122] (Note 14) The M source is selected from one or more oxides of the elements Mn, Fe, Ni, Co, Al, Zr, Y, Ca, Li, Rb, Cs, W, Ce, Mo, Ba, Ti, Mg, Ta, Nb, V, Sc, Sr, B, and Cu, or salts thereof, or organic compounds thereof. Preferably, the M source is selected from carbonates, phosphates, nitrates, or oxides of one or more elements from among Mn, Fe, Ni, Co, Al, Zr, Y, Ca, Li, Rb, Cs, W, Ce, Mo, Ba, Ti, Mg, Ta, Nb, V, Sc, Sr, B, and Cu. More preferably, the M source is selected from one or more of manganese dioxide, manganese carbonate, nickel oxide, nickel carbonate, ferric oxide, ferrous oxalate, ferrous phosphate, and copper sulfate. A method for producing a positive electrode material for a sodium-ion battery as described in Appendix 10, characterized by the above.

[0123] (Note 15) The aforementioned source A is selected from oxides of one or more elements from among the elements Co, Al, Zr, Y, Ca, Li, Rb, Cs, W, Ce, Mo, Ba, Ti, Mg, Ta, Nb, V, Sc, Sr, B, and Cu, or salts thereof, or organic compounds thereof. Preferably, the A source is selected from carbonates, phosphates, nitrates, or oxides of one or more elements from among Al, Zr, Y, Ca, Li, Rb, Cs, Ba, Ti, Mg, Nb, V, Sc, Sr, B, and Cu. More preferably, the A source is selected from one or more of the following: calcium oxide, boron oxide, niobium oxide, aluminum oxide, titanium oxide, magnesium oxide, copper oxide, yttrium oxide, zirconium oxide, or copper sulfate. A method for producing a positive electrode material for a sodium-ion battery as described in Appendix 10, characterized by the above.

[0124] (Note 16) A sodium ion cathode material manufactured by the method for manufacturing a sodium ion battery cathode material described in Appendix 10.

[0125] (Note 17) The positive electrode active material includes at least one of the sodium ion battery positive electrode materials described in any one of Appendix 1 to 4, or Appendix 16. A positive electrode for a sodium-ion battery characterized by the following features.

[0126] (Note 18) The sodium ion battery described in Appendix 17 includes a positive electrode, a negative electrode, and a sodium salt-containing electrolyte. A sodium-ion battery characterized by the following features.

[0127] (Note 19) Manufactured using the sodium-ion battery described in Appendix 18, A power system, energy storage system, or mobile storage device characterized by the following:

Claims

1. A positive electrode material for a sodium ion battery, comprising: The general formula of the positive electrode material is Na １＋ａ M ｄ Zn ｘ O ２＋ｃ wherein -0.40≦a≦0.25, 0.78<d≦0.93, 0.1<x≦0.22, and -0.3<c<0.3; M is one or more selected from Mn, Fe, Ni, Co, Al, Zr, Y, Ca, Li, Rb, Cs, W, Ce, Mo, Ba, Ti, Mg, Ta, Nb, V, Sc, Sr, B, and Cu elements, with the proviso that there is one diffraction peak at a diffraction angle 2θ value of around 16°, at least five diffraction peaks at diffraction angle 2θ values ​​of 30 to 40°, and one diffraction peak at a diffraction angle 2θ value of around 41°; A positive electrode material for a sodium ion battery.

2. The positive electrode material for sodium ion batteries Na １＋ａ M ｙ Zn ｘ O ２＋ｃ In the formula, M contains element A and element B, and the content of element A is represented by b, the general formula of the positive electrode material is Na １＋ａ B １－ｂ－ｘ Zn ｘ A ｂ O ２＋ｃ wherein, in the formula, 0.1<x≦0.22, 0.0<b≦0.06, −0.40≦a≦0.25, −0.3<c<0.3, y=1−x, and A and B are each one or more selected from Mn, Fe, Ni, Co, Al, Zr, Y, Ca, Li, Rb, Cs, W, Ce, Mo, Ba, Ti, Mg, Ta, Nb, V, Sc, Sr, B, and Cu elements, and A and B may be the same or different; Preferably, the B element in the positive electrode material for a sodium ion battery is one or more selected from Mn, Fe, Ni, and Co, More preferably, the general formula of the positive electrode material for a sodium ion battery is Na １＋ａ Ni ｙ Mn ｚ Fe １－ｘ－ｙ－ｚ－ｂ Zn ｘ A ｂ O ２＋ｃ wherein 0.15≦y≦0.35, 0.20≦z≦0.38, −0.40≦a≦0.25, 0.0<b≦0.06, −0.3<c<0.3, 0.1<x≦0.22; The positive electrode material for a sodium ion battery according to claim 1 .

3. The mass percent content of zinc element in the sodium ion battery positive electrode material is 5.0 to 20.0%, Preferably, the mass percent content of zinc element in the sodium ion battery positive electrode material is 5.0 to 15.0%; More preferably, the powder X-ray diffraction pattern of the positive electrode material for a sodium ion battery is α-NaFeO ４ This indicates that the layer structure is The positive electrode material for a sodium ion battery according to claim 1 .

4. In the powder X-ray diffraction pattern of the sodium ion battery positive electrode material, the half width of a diffraction peak having a 2θ value of 30 to 40° is 0.04 to 0.4°, preferably 0.04 to 0.30°, and more preferably 0.04 to 0.25°; and / or the second strongest peak is present at around 16° 2θ and the strongest peak is present at around 41° 2θ, preferably the second strongest peak is present at around 16.5° 2θ and the strongest peak is present at around 41.6° 2θ, and / or the half widths of the diffraction peaks at around 16° 2θ and 41° 2θ are 0.05 to 0.35°, preferably 0.05 to 0.30°, more preferably 0.05 to 0.25°; The positive electrode material for a sodium ion battery according to claim 1 .

5. In the powder X-ray diffraction pattern of the sodium ion battery positive electrode material, six diffraction peaks are present at 2θ values ​​of 30 to 40°, and the 2θ values ​​are around 32°, around 33°, around 34°, around 35°, and around 36°, respectively; Preferably, the 2θ values ​​of the six diffraction peaks are around 31.8°, around 33.4°, around 34.4°, around 35.2°, around 36.3°, and around 36.6°, respectively. The positive electrode material for a sodium ion battery according to any one of claims 1 to 4.

6. In a powder X-ray diffraction pattern (XRD) of the sodium ion battery positive electrode material, the full width at half maximum FWHM of a diffraction peak at a diffraction angle 2θ of about 31.8° is 0.06 to 0.25°, the full width at half maximum FWHM of a diffraction peak at a diffraction angle 2θ of about 34.4° is 0.07 to 0.25°, and the full width at half maximum FWHM of a diffraction peak at a diffraction angle 2θ of about 36.3° is 0.06 to 0.25°, Preferably, the ratio of the peak intensity of the diffraction peak at a diffraction angle 2θ of around 31.8° to the peak intensity of the diffraction peak at a diffraction angle 2θ of around 34.4° is (1 to 2):1, preferably the ratio is (1.2 to 1.8):1, more preferably the ratio is (1.3 to 1.7):1, and / or the ratio of the peak intensities of the diffraction peak at a diffraction angle 2θ of about 36.3° to the diffraction peak at a diffraction angle 2θ of about 34.4° is (2 to 3):1, preferably (2.2 to 2.8):1, and more preferably (2.2 to 2.7):1; The positive electrode material for a sodium ion battery according to any one of claims 1 to 4.

7. In the powder X-ray diffraction pattern (XRD) of the positive electrode material for a sodium ion battery, The full width at half maximum (FWHM) of the diffraction peak has one or more of the following characteristics: (1) The full width at half maximum (FWHM) of the diffraction peak at a diffraction angle 2θ of approximately 16.5° is 0.08 to 0.25°, (2) The full width at half maximum (FWHM) of the diffraction peak at a diffraction angle 2θ of approximately 33.4° is 0.08 to 0.23°, (3) The full width at half maximum (FWHM) of the diffraction peak at a diffraction angle 2θ of approximately 35.2° is 0.07 to 0.22°, (4) The full width at half maximum (FWHM) of the diffraction peak at a diffraction angle 2θ of approximately 36.6° is 0.08 to 0.20°, and (5) The full width at half maximum (FWHM) of the diffraction peak at a diffraction angle 2θ of approximately 41.6° is 0.06 to 0.20°. The sodium ion positive electrode material according to any one of claims 1 to 4.

8. The specific surface area of ​​the positive electrode material for a sodium ion battery is 0.25 to 1.5 m ２ / g, preferably 0.69 to 1.5 m ２ / g, and / or the particle size D50 of the sodium ion battery positive electrode material is 2 to 15 μm, preferably 5.3 to 15 μm; The positive electrode material for a sodium ion battery according to any one of claims 1 to 4.

9. The mass percent content of residual alkali of the sodium ion battery positive electrode material is within 3.15%, preferably 0.7 to 3.15%; The positive electrode material for a sodium ion battery according to any one of claims 1 to 4.

10. A precursor is obtained by mixing an M source and a Zn source in a certain ratio, and then uniformly mixing the precursor with a Na source, or after uniformly mixing an M source, a Zn source, and a Na source, sintering at a temperature of 750 to 980°C, and / or the sintering time is 8 to 40 hours, and cooling and pulverizing to obtain a positive electrode material for a sodium ion battery; The method for producing the positive electrode material for a sodium ion battery according to any one of claims 1 to 4.

11. The firing temperature is 880 to 960°C, and / or the firing time is 15 to 25 hours, and preferably, the firing temperature is increased at a rate of 3 to 10°C / min to perform constant temperature firing treatment. The method for producing a positive electrode material for a sodium ion battery according to claim 10.

12. The grinding is performed using a disc grinder, and preferably, the distance between discs is 0 to 2 mm, and / or the rotation speed is 500 to 3000 rpm. The method for producing a positive electrode material for a sodium ion battery according to claim 10.

13. The sodium source is one or more selected from sodium hydroxide, sodium carbonate, sodium nitrate, sodium oxalate, sodium chloride, sodium fluoride, and sodium acetate; The method for producing a positive electrode material for a sodium ion battery according to claim 10.

14. the M source is selected from oxides of one or more elements selected from Mn, Fe, Ni, Co, Al, Zr, Y, Ca, Li, Rb, Cs, W, Ce, Mo, Ba, Ti, Mg, Ta, Nb, V, Sc, Sr, B, and Cu, or salts thereof, or organic compounds thereof; Preferably, the M source is selected from carbonates, phosphates, nitrates or oxides of one or more elements selected from the group consisting of Mn, Fe, Ni, Co, Al, Zr, Y, Ca, Li, Rb, Cs, W, Ce, Mo, Ba, Ti, Mg, Ta, Nb, V, Sc, Sr, B and Cu; More preferably, the M source is one or more selected from manganese dioxide, manganese carbonate, nickel oxide, nickel carbonate, ferric oxide, ferrous oxalate, ferrous phosphate, and copper sulfate. The method for producing a positive electrode material for a sodium ion battery according to claim 10.

15. the A source is selected from oxides of one or more elements selected from Co, Al, Zr, Y, Ca, Li, Rb, Cs, W, Ce, Mo, Ba, Ti, Mg, Ta, Nb, V, Sc, Sr, B, and Cu, or salts thereof, or organic compounds thereof; Preferably, the A source is selected from carbonates, phosphates, nitrates or oxides of one or more elements selected from the group consisting of Al, Zr, Y, Ca, Li, Rb, Cs, Ba, Ti, Mg, Nb, V, Sc, Sr, B and Cu; More preferably, the A source is one or more selected from calcium oxide, boron oxide, niobium oxide, aluminum oxide, titanium oxide, magnesium oxide, copper oxide, yttrium oxide, zirconium oxide, and copper sulfate. The method for producing a positive electrode material for a sodium ion battery according to claim 10.

16. A sodium ion positive electrode material produced by the method for producing a positive electrode material for a sodium ion battery according to claim 10.

17. The positive electrode material for a sodium ion battery according to any one of claims 1 to 4 is contained as a positive electrode active material. A positive electrode for a sodium ion battery.

18. 18. A sodium-ion battery comprising the positive electrode of claim 17, a negative electrode, and a sodium salt-containing electrolyte. A sodium-ion battery characterized by:

19. Manufactured using the sodium ion battery of claim 18.

1. A power system, energy storage system or mobile storage device comprising:

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