Positive electrode material for single crystal sodium ion battery, positive electrode for sodium ion battery, and the sodium ion battery

Abstract

To provide a positive electrode material for a single crystal sodium ion battery, which has a single crystal topography, has good structural stability and integrity, does not crack particles during a cycling, and improves a cycling stability of a sodium ion battery.SOLUTION: A positive electrode material for a single crystal sodium ion battery includes a chemical formula represented by Na1+aNi1-x-y-z-cMnxFeyMzNcO2. Here, -0.40≤a≤0.25, 0.08≤x≤0.5, 0.05≤y≤0.5, 0≤z<0.26, and 0<c<0.1, and both of M and N are each one or two or more selected from a group consisting of Ti, Zn, Co, Mn, Al, Zr, Y, Ca, Li, Rb, Cs, W, Ce, Mo, Ba, Mg, Ta, Nb, V, Sc, Sr, B, F, P, and Cu elements.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to the technical field of sodium ion batteries, and more particularly to a positive electrode material for single-crystal sodium ion batteries, and its manufacturing method and application. [Background technology]

[0002] As the competition for lithium-ion batteries intensifies, the price of lithium salts is rising in addition to supply and demand relations and resource restrictions, and sodium-ion batteries, which have cost advantages, are gradually becoming the focus of research by major companies and universities. Sodium-ion batteries operate on the same principle as lithium-ion batteries, but compared to lithium-ion batteries, sodium ions have a larger ionic radius and a slower diffusion rate, so sodium ions have some disadvantages in terms of energy density and cycle characteristics.

[0003] After extensive research in various fields over the past decade, sodium-ion batteries have been developed into a system of products mainly consisting of transition metal oxides, Prussian blue, polyanion phosphates, etc. Among them, transition metal oxides have a relatively high specific capacity, making them popular. However, their poor cycle performance and low energy density are important factors affecting the application of positive electrode materials for sodium-ion batteries.

[0004] Transition metal oxides currently available on the market are primarily divided into two types: nickel-manganese-iron-copper oxides containing copper, and nickel-iron-manganese oxides. In either type, varying the ratio of nickel, iron, manganese, and copper elements can produce cathode materials for sodium-ion batteries with different performance characteristics. The different element ratios also affect the stability of the materials when in contact with the electrolyte. Factors that affect the cycle life of cathode materials for sodium-ion batteries are: 1) the restructuring of the surface crystalline structure during cycling; and 2) the destruction of agglomerated particles due to anisotropic volume expansion during cycling. Research has shown that the interparticle interconnection structure within agglomerated particles leads to localized increases in current density, which generates significant stress and thereby affects the cycling characteristics of the material. Furthermore, mismatches in the state of charge between different parts of the particles also affect the electrochemical performance of the electrode.

[0005] In addition, when the amount of desodium in the positive electrode material for sodium-ion batteries is relatively large, the structure becomes very fragile, and the active metals and oxygen in the lattice are displaced. At a certain high temperature and pressure, the atomic rearrangement and reorganization gradually intensifies, and the volume and material phase of the crystal grains change significantly. Meanwhile, when the positive electrode material is desodiumed, its oxidizing power becomes strong, and it is very easy to cause chemical and electrochemical reactions with the electrolyte, which makes the material easy to deoxidize, and the transition metals dissolve. Especially under high voltage, the electrolyte is oxidized, and H + is generated, which increases the acidity of the electrolyte, which causes the surface film of the electrode material to be destroyed by HF, which further changes the composition and structure of the interface, which seriously affects the electrochemical and cycling performance of the material. Summary of the Invention [Problem to be solved by the invention]

[0006] The technical problem to be solved by the present invention is to provide a positive electrode material for a single crystal sodium ion battery that improves the cycle performance of the sodium ion battery.

[0007] In view of the above technical problems, as a result of intensive research by the inventors of the present application, a cathode material for a single-crystal sodium-ion battery having single-crystal topography is obtained. By adopting surface coating or simultaneously performing bulk-phase doping and surface coating modification, direct contact between the material and the electrolyte, especially HF in the electrolyte, can be effectively avoided, thereby preventing the occurrence of side reactions, suppressing the crystal phase transition of the material, improving the cycle stability of the material, and applying it to a sodium-ion battery, especially a power-type sodium-ion battery, can effectively improve the high-temperature high-voltage cycle performance of the battery, especially the high-temperature stability.

Means for Solving the Problems

[0008] The technical solution of the present invention is as follows. The present invention provides a cathode material for a single-crystal sodium-ion battery, and the cathode material for the single-crystal sodium-ion battery contains elements having a composition represented by Chemical Formula 1. The Chemical Formula 1 is Na 1+a Ni 1-x-y-z-c Mn x Fe y M z N c O2, where -0.40 ≤ a ≤ 0.25, 0.08 ≤ x ≤ 0.5, 0.05 ≤ y ≤ 0.5, 0 ≤ z < 0.26, 0 < c < 0.1. M is a doping element, and N is a coating element. Both M and N are one or more selected from the elements of Ti, Zn, Co, Mn, Al, Zr, Y, Ca, Li, Rb, Cs, W, Ce, Mo, Ba, Mg, Ta, Nb, V, Sc, Sr, B, F, P or Cu.

[0009] Preferably, in the above cathode material for a single-crystal sodium-ion battery, -0.40 ≤ a ≤ 0, 0.15 ≤ x ≤ 0.5, 0.15 ≤ y ≤ 0.5.

[0010] Preferably, in the above-mentioned single crystal sodium ion battery positive electrode material, M is one or more selected from Zn, Ti, Co, Al, Zr, Y, Ca, Li, Rb, Cs, W, Ce, Mo, Ba, Mg, Ta, Nb, V, Sc, Sr, B, F, P, and Cu, preferably one or more selected from Zn, Al, B, Ti, Ca, Y, Mg, Nb, Zr, and Cu, more preferably Zn, and preferably 0≦z≦0.13.

[0011] Preferably, in the above-mentioned single crystal sodium ion battery positive electrode material, the N is one or more selected from Al, Ti, Co, Mn, Y, B, F, P, Nb, Zr, W, Sr, and Mg, preferably one or more selected from Al, Ti, B, Nb, and Mg, and preferably 0. <c<0.05である。

[0012] Preferably, the monocrystalline sodium ion battery cathode material has a microscopic topography of monocrystalline topography under a scanning electron microscope, and the shape of the monocrystalline topography particles is preferably one or more of spherical, pseudo-spherical, polygonal, or layered sheet.

[0013] Preferably, in a powder X-ray diffraction spectrum (XRD) of the single crystal sodium ion battery positive electrode material, the full width at half maximum FWHM(110) of a (110) diffraction peak at a diffraction angle 2θ of around 64.9° is 0.08 to 0.35.

[0014] Preferably, the single crystal sodium ion battery positive electrode material has a green density of 2.8 to 4.2 g / cm under a pressure of 7000 to 9000 kg. 3 is.

[0015] Preferably, the water mass content of the monocrystalline sodium-ion battery cathode material is less than 1500 ppm, preferably less than 1000 ppm, more preferably less than 900 ppm.

[0016] Preferably, the pH value of the monocrystalline sodium ion battery positive electrode material is within 12.6.

[0017] Preferably, the specific surface area of ​​the single crystal sodium ion battery positive electrode material is 0.35 to 1.2 m 2 / g.

[0018] Preferably, the particle size D of the single crystal sodium ion battery positive electrode material V 50 is 2.00 to 16.0 μm, and preferably 2.50 to 12.0 μm.

[0019] The present invention further provides a method for producing the above-mentioned single-crystal sodium-ion battery positive electrode material, Step (1) of mixing raw materials including a sodium source compound, a manganese source compound, and an iron source compound, optionally adding a nickel source compound and an M source compound, and then sintering the mixture for the first time and pulverizing the mixture to obtain a semi-finished product; and step (2) mixing the semi-finished product obtained in step (1) with the raw material of the N source compound, followed by a second sintering and pulverization to obtain a single-crystal sodium-ion battery positive electrode material.

[0020] Preferably, in the above manufacturing method, the first sintering temperature in step (1) is 860 to 990°C, preferably 880 to 980°C, and the isothermal time is preferably 6 to 40 hours.

[0021] Preferably, in the above manufacturing method, the second sintering temperature in step (2) is 350 to 900°C, preferably 350 to 800°C, and the isothermal time is preferably 2 to 15 hours.

[0022] Preferably, in the above production method, the grinding pressure in both step (1) and step (2) is 0.1 to 1 MPa.

[0023] Preferably, in the above production method, the sodium source compound includes a salt and / or hydroxide containing sodium element, and preferably, the sodium source compound is one or more compounds selected from the group consisting of sodium carbonate, sodium formate, sodium hydroxide, sodium acetate, sodium chloride, and sodium fluoride.

[0024] Preferably, in the above production method, the manganese source compound includes one or more oxides, hydroxides, and salts containing manganese element, and preferably the manganese source compound is one or more selected from the group consisting of dimanganese trioxide, trimanganese tetroxide, manganese oxide, manganese carbonate, manganese oxalate, manganese sulfate, manganese acetate, manganese chloride, and manganese nitrate.

[0025] Preferably, in the above production method, the nickel source compound includes one or more of an oxide, hydroxide, or salt containing nickel element, and preferably the nickel source compound is one or more selected from the group consisting of nickel carbonate, nickel oxalate, nickel sulfate, nickel acetate, nickel chloride, and nickel nitrate.

[0026] Preferably, in the above production method, the iron source compound includes one or more of oxides, hydroxides, and salts containing iron element, and preferably the iron source compound is one or more selected from the group consisting of ferrous oxide, ferrous oxalate, ferrous sulfate, ferrous acetate, and ferrous nitrate.

[0027] Preferably, the M source compound includes an oxide and / or a salt containing the M element, and preferably, the M source compound includes one or more of calcium oxide, calcium hydroxide, diboron trioxide, boric acid, niobium oxide, aluminum oxide, titanium oxide, magnesium oxide, copper oxide, yttrium trioxide, zirconium oxide, sodium fluoride, lithium fluoride, copper oxide, zinc oxide, and copper sulfate.

[0028] Preferably, the N source compound includes an oxide and / or a salt containing N element, and preferably includes one or more of calcium oxide, diboron trioxide, boric acid, niobium oxide, aluminum oxide, aluminum acetate, aluminum nitrate, titanium oxide, magnesium oxide, magnesium acetate, magnesium nitrate, copper oxide, yttrium trioxide, zirconium oxide, zirconium acetate, sodium fluoride, lithium fluoride, titanium white powder, titanium oxide dispersion, zinc oxide, and copper sulfate.

[0029] The present invention further provides a single-crystal sodium-ion battery positive electrode material produced by the above-mentioned production method.

[0030] The present invention further provides a positive electrode for a sodium ion battery, wherein the active material is the above-mentioned single-crystal positive electrode material for a sodium ion battery.

[0031] The present invention further provides a sodium ion battery comprising the above-described positive electrode for a sodium ion battery.

[0032] The present invention further provides applications of the above-mentioned monocrystalline sodium ion battery positive electrode material, the above-mentioned sodium ion battery positive electrode, or the above-mentioned sodium ion battery in photovoltaic power generation, wind power generation, smart grid, distributed power plant, home energy storage battery, low-end motorcycle battery, or low-energy density power battery. [Effects of the Invention]

[0033] The beneficial effects of the present invention are as follows: (1) The single-crystal sodium-ion battery positive electrode material of the present invention has a specific chemical composition and single-crystal topography, so that the positive electrode material for sodium-ion batteries has good structural stability and does not undergo significant structural changes due to frequent desorption of sodium ions during charging and discharging of the sodium-ion battery. Furthermore, the material has a perfect structure, good processability, and no particle cracking during cycling. It effectively prevents direct contact between the material surface and the electrolyte, especially with HF in the electrolyte, preventing side reactions and improving the cycling stability of the sodium-ion battery. (2) Through the coating treatment of the present invention, the monocrystalline sodium ion battery positive electrode material has a low pH value, a low residual alkali content, and a low moisture content, which prevents the monocrystalline sodium ion battery positive electrode material from absorbing water and gelling during the battery pulping process, thereby improving the stability of the sodium ion battery electrode slurry and thereby further improving the cycle stability of the sodium ion battery. [Brief explanation of the drawings]

[0034] [Figure 1] FIG. 1 is an SEM image (magnification: 5000 times) of the single-crystal sodium-ion battery positive electrode material produced in Example 1. [Figure 2] FIG. 2 is an SEM image (magnification: 5000 times) of the single-crystal sodium ion battery positive electrode material produced in Example 2. [Figure 3] FIG. 3 is an SEM image (magnification: 5000 times) of the single-crystal sodium ion battery positive electrode material produced in Example 3. [Figure 4] FIG. 4 is an SEM image (magnification: 5000 times) of the single-crystal sodium ion battery positive electrode material produced in Example 4. [Figure 5] FIG. 5 is an SEM image (magnification: 5000 times) of the single-crystal sodium ion battery positive electrode material produced in Example 5. [Figure 6] FIG. 6 is an SEM image (magnification: 5000 times) of the single-crystal sodium ion battery positive electrode material produced in Example 6. [Figure 7]FIG. 7 is an SEM image (magnification: 5000 times) of the single-crystal sodium ion battery positive electrode material produced in Example 7. [Figure 8] FIG. 8 is an SEM image (magnification: 5000 times) of the single-crystal sodium ion battery positive electrode material produced in Example 8. [Figure 9] FIG. 9 is an SEM image (magnification: 5000 times) of a tab containing the single-crystal sodium-ion battery positive electrode material produced in Example 1. [Figure 10] FIG. 10 is an SEM image (magnification: 5000 times) of a tab containing the single-crystal sodium-ion battery positive electrode material produced in Example 2. [Figure 11] FIG. 11 is an SEM image (magnification: 5000 times) of a tab containing the single-crystal sodium-ion battery positive electrode material produced in Example 3. [Figure 12] FIG. 12 is an SEM image (magnification: 5000 times) of a tab containing the single-crystal sodium-ion battery positive electrode material produced in Example 4. [Figure 13] FIG. 13 is an SEM image (magnification: 5000 times) of a tab containing the single-crystal sodium-ion battery positive electrode material produced in Example 5. [Figure 14] FIG. 14 is an SEM image (magnification: 5000 times) of a tab containing the single-crystal sodium-ion battery positive electrode material produced in Example 6. [Figure 15] FIG. 15 is an SEM image (magnification: 5000 times) of a tab containing the single-crystal sodium-ion battery positive electrode material produced in Example 7. [Figure 16] FIG. 16 is an SEM image (magnification: 5000 times) of a tab containing the single-crystal sodium-ion battery positive electrode material produced in Example 8. [Figure 17] FIG. 17 is an SEM image (magnification: 5000 times) of the single-crystal sodium ion battery positive electrode material produced in Example 9. [Figure 18] FIG. 18 is an SEM image (magnification: 5000 times) of a tab containing the single-crystal sodium-ion battery positive electrode material produced in Example 9. [Figure 19]FIG. 19 is an SEM image (magnification: 5000x) of the positive electrode tab of the BA-C1 battery after 50 cycles. [Figure 20] FIG. 20 is a cycle graph of the button batteries of Examples 1 to 9. DETAILED DESCRIPTION OF THE INVENTION

[0035] In order to clarify the purpose, technical solutions and technical effects of the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. The embodiments described below are only some of the embodiments of the present invention, but not all of the embodiments. All other embodiments obtained by those skilled in the art without performing creative work together with the embodiments of the present invention fall within the scope of protection of the present invention.

[0036] D of the present invention V 50 is the particle size corresponding to the percentage of the volume cumulative particle size distribution number in the sample reaching 50%.

[0037] In order to improve the cycling performance of sodium ion batteries, the present invention prepares the positive electrode material for sodium ion batteries as single crystal particles, improves the structural stability of the material, effectively inhibits structural changes, and strengthens the reversibility of the material. At the same time, the positive electrode material for sodium ion batteries is surface-coated, or bulk-phase doped and surface-coated simultaneously, effectively avoiding direct contact between the material and the electrolyte, especially HF in the electrolyte, thereby preventing side reactions and inhibiting the crystalline phase transition of the material, thereby improving the cycling stability of the material.

[0038] In one specific embodiment of the present invention, the present invention provides a single-crystal sodium-ion battery cathode material, the material comprising elements having a composition represented by Chemical Formula 1: The formula 1 is Na 1+a Ni 1-x-y-z-c Mn x Fe y M z N cIt is O2, where -0.40 ≦ a ≦ 0.25, 0.08 ≦ x ≦ 0.5, 0.05 ≦ y ≦ 0.5, 0.0 ≦ z < 0.26, 0 < c < 0.1. M is a doping element, and N is a coating element. The M and N are one or more selected from the group consisting of Ti, Zn, Co, Mn, Al, Zr, Y, Ca, Li, Rb, Cs, W, Ce, Mo, Ba, Mg, Ta, Nb, V, Sc, Sr, B, F, P, or Cu elements.

[0039] In a preferred embodiment of the present invention, in the above chemical formula 1, -0.40 ≦ a ≦ 0, 0.15 ≦ x ≦ 0.5, and 0.15 ≦ y ≦ 0.5.

[0040] In a preferred embodiment of the present invention, the above M is one or more selected from Zn, Ti, Co, Al, Zr, Y, Ca, Li, Rb, Cs, W, Ce, Mo, Ba, Mg, Ta, Nb, V, Sc, Sr, B, F, P, or Cu, preferably one or more of Zn, Al, B, Ti, Ca, Y, or Cu, more preferably Zn, and preferably 0 ≦ z ≦ 0.13.

[0041] In yet another preferred embodiment of the present invention, the N is one or more selected from Al, Ti, Co, Mn, Y, B, F, P, Nb, Zr, W, Sr, or Mg, preferably one or more of Al, Ti, B, Nb, or Mg, and preferably 0 < c < 0.05.

[0042] In the present invention, the above positive electrode material for a single crystal sodium ion battery has a microscopic topography that is a single crystal topography under a scanning electron microscope, and the shape of the single crystal topography particles is one or more of spherical, pseudo-spherical, polygonal, or layered sheet.

[0043] In the present invention, in the powder X-ray diffraction spectrum (XRD) of the above-mentioned single crystal sodium ion battery positive electrode material, the full width at half maximum (FWHM)(110) of the (110) diffraction peak at a diffraction angle 2θ of around 64.9° (in the present invention, the diffraction angle around X° that appears is X°±1°, for example, around 64.9° is 64.9°±1°, i.e., 63.9° to 65.9°) is 0.08 to 0.35.

[0044] In the present invention, the green density of the single crystal sodium ion battery positive electrode material under a pressure of 7000 to 9000 kg is 2.8 to 4.2 g / cm 3 It is between.

[0045] In the present invention, the specific surface area of ​​the monocrystalline sodium ion battery positive electrode material is 0.35 to 1.2 m 2 / g.

[0046] In the present invention, the particle size D of the single crystal sodium ion battery positive electrode material V 50 is 2.00 to 16.0 μm, and preferably 2.50 to 12.0 μm.

[0047] The monocrystalline sodium-ion battery positive electrode material of the present application has the above-mentioned specific chemical composition and topography, so that the specific surface area (BET) of the material is within a reasonable range, the intermolecular forces on the surface of the material are in a relatively balanced position, self-aggregation is difficult even in a relatively humid environment, and the moisture level of the material is relatively low.

[0048] In the present invention, the water content of the single crystal sodium ion battery positive electrode material is less than 1500 ppm, preferably less than 1000 ppm, and more preferably less than 900 ppm.

[0049] In the present invention, the pH value of the single crystal sodium ion battery positive electrode material is within 12.6.

[0050] The monocrystalline sodium ion battery positive electrode material of the present application has the above-mentioned specific chemical composition and topography, and therefore undergoes a coating treatment to ensure that the monocrystalline sodium ion battery positive electrode material has a low pH value, a low residual alkali content, and a low water content, thereby preventing the monocrystalline sodium ion battery positive electrode material from absorbing water and gelling during the battery pulping process, and improving the stability of the sodium battery electrode slurry.

[0051] The present invention further provides a method for producing the above single-crystal sodium-ion battery cathode material, comprising at least two sintering steps and two grinding steps.

[0052] In a preferred embodiment of the present invention, the production method includes: Step (1) of mixing raw materials including a sodium source compound, a manganese source compound, and an iron source compound, and optionally adding raw materials for a nickel source compound and an M source compound, and then performing a first sintering and pulverizing to obtain a semi-finished product; and step (2) mixing the semi-finished product obtained in step (1) with a raw material containing an N source compound, followed by a second sintering and pulverization to obtain a single-crystal sodium-ion battery positive electrode material.

[0053] In the above-mentioned manufacturing method, the first sintering in step (1) is performed at a temperature of 860 to 990°C for 6 to 40 hours, and preferably, the first sintering temperature is 880 to 980°C, and the atmosphere used for sintering is air, oxygen, or a mixed gas of air and oxygen; The second sintering in step (2) is performed at a temperature of 350 to 900°C for 2 to 15 hours, and preferably, the second sintering temperature is 350 to 800°C, and the atmosphere used for sintering is air, oxygen, or a mixed gas of air and oxygen; The grinding pressure in both steps (1) and (2) is 0.1 to 1 MPa.

[0054] In the above production method, the sodium source compound is a salt and / or hydroxide containing sodium, and includes, for example, one or more of sodium carbonate, sodium formate, sodium hydroxide, sodium acetate, sodium chloride, and sodium fluoride.

[0055] In the above production method, the manganese source compound is one or more of a manganese-containing oxide, hydroxide, or salt, and includes, for example, one or more of dimanganese trioxide, trimanganese tetroxide, manganese oxide, manganese carbonate, manganese oxalate, manganese sulfate, manganese acetate, manganese chloride, and manganese nitrate.

[0056] In the above production method, the nickel source compound is one or more of a nickel-containing oxide, hydroxide, or nickel-containing salt, and includes, for example, one or more of nickel carbonate, nickel oxalate, nickel sulfate, nickel acetate, nickel chloride, and nickel nitrate.

[0057] In the above production method, the iron source compound is one or more of iron-containing oxides, hydroxides, and iron-containing salts, and includes, for example, one or more of iron trioxide, ferrous oxalate, ferrous sulfate, ferrous acetate, and ferrous nitrate.

[0058] In the above production method, the M source compound includes an oxide and / or a salt containing the M element, and includes, for example, one or more of calcium oxide, calcium hydroxide, diboron trioxide, boric acid, niobium oxide, aluminum oxide, titanium oxide, magnesium oxide, copper oxide, yttrium trioxide, zirconium oxide, sodium fluoride, lithium fluoride, copper oxide, zinc oxide, and copper sulfate.

[0059] In the above production method, the N source compound includes an oxide and / or a salt containing N element, and includes, for example, one or more of calcium oxide, diboron trioxide, boric acid, niobium oxide, aluminum oxide, aluminum acetate, aluminum nitrate, titanium oxide, magnesium oxide, magnesium acetate, magnesium nitrate, copper oxide, yttrium trioxide, zirconium oxide, zirconium acetate, sodium fluoride, lithium fluoride, titanium white powder, titanium oxide dispersion, zinc oxide, and copper sulfate.

[0060] The present invention further provides a positive electrode for a sodium ion battery, wherein the active material is the above-mentioned single-crystal sodium ion battery positive electrode material.

[0061] The present invention further provides a sodium ion battery comprising the above-described positive electrode for a sodium ion battery.

[0062] The sodium ion battery of the present invention further includes a negative electrode, an electrolyte containing a sodium salt, a separator, and an aluminum plastic film. Specifically, the positive electrode comprises a positive electrode current collector, a material including a positive electrode active material coated on the positive electrode current collector, a binder, a conductive additive, etc., and the positive electrode active material is the positive electrode material of the present invention. The negative electrode comprises a metallic sodium sheet or a current collector, a material including a negative electrode active material coated on the current collector, a binder, a conductive additive, etc., and the separator is a PP / PE film commonly used in the industry and is used to separate the positive electrode and negative electrode from each other, and the aluminum plastic film is a container for the positive electrode, negative electrode, separator, and electrolyte.

[0063] The binder in the present invention is primarily used to improve the binding properties between positive electrode active material particles and between the positive electrode active material particles and the current collector. The binder in the present invention can be selected from commercially available binders commonly used in the industry. Specifically, the binder may be selected from polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene oxide-containing polymers, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene 1,1-difluoroethylene, polyethylene, polypropylene, styrene-butadiene rubber, acrylated (esterified) styrene-butadiene rubber, epoxy resin, nylon, or a composition thereof.

[0064] The conductive additive in the present invention may be selected from commercially available conductive additives 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, ketjen black, or carbon fiber), metal-based materials (e.g., metal powders or metal fibers containing copper, nickel, aluminum, silver, etc.), conductive polymers (e.g., polyphenylene derivatives), or compositions thereof.

[0065] The present invention further provides applications of the above-mentioned single-crystal sodium ion battery positive electrode material, or the above-mentioned sodium ion electrode, or the above-mentioned sodium ion battery in photovoltaic power generation, wind power generation, smart grid, distributed power plant, home energy storage battery, low-end motorcycle battery, or low-energy density power battery.

[0066] The beneficial effects of the present invention will be further illustrated below by specific examples.

[0067] All raw materials and reagents used in this invention were purchased from major manufacturers on the market. If the manufacturer or concentration is not specified, they are all commonly available analytical raw materials or reagents, and are not particularly limited as long as they achieve the desired effect. All instruments and equipment used in this example were purchased from major manufacturers on the market, and are not particularly limited as long as they achieve the desired effect. If specific techniques or conditions are not specified in this example, they are performed according to the techniques or conditions described in the literature in the relevant technical field or in accordance with the product instructions.

[0068] The raw materials and instruments used in the following examples and comparative examples are as shown in Table 1.

[0069] [Table 1]

[0070] [Table 2]

[0071] Example 1 The molar ratio of elements was Na:Mn:Ni:Fe:B = 0.87:0.33:0.33:0.33:0.01, and the total weight was 1.59 kg. The corresponding weights of sodium carbonate, manganese carbonate, nickel carbonate, iron trioxide, and boron oxide were weighed and mixed in an ultra-high speed multi-function mixer at a rotation speed of 4000 r / min for 20 minutes. The homogeneously mixed material was placed in a muffle furnace and kept at 870 °C in an air atmosphere for 12 hours, then naturally cooled. The material was then pulverized in an air flow mill at a pulverization pressure of 0.62 MPa to obtain a semi-finished product. 1.08 kg of the above semi-finished product and 0.0097 kg of aluminum oxide were weighed, added to a ball mill can, and ball milled at 40 Hz for 10 minutes. The homogeneously mixed material was then placed in a muffle furnace and heated at 800°C in an air atmosphere for 4 hours, then naturally cooled. The mixture was then pulverized using an airflow pulverizer at a pulverization pressure of 0.58 MPa and sieved to obtain a single-crystalline sodium-ion battery positive electrode material C1.

[0072] The cathode materials were characterized and analyzed according to the following methods. 1) Component analysis The components of the positive electrode material were analyzed using ICP. (1) Sample pretreatment Weigh 0.2000-0.2100g (accuracy from 0.001g) of sample into a 100mL quartz beaker, add 10mL of aqua regia (37wt% concentrated hydrochloric acid and 65wt% concentrated nitric acid in a volume ratio of 1:1) along the beaker wall, cover the surface dish, heat at 180°C for 30min, transfer the entire solution into a 50mL measuring flask, add deionized water to the volume, shake well, and then aspirate 1mL of the solution from the well-shaken 50mL measuring flask into a 100mL measuring flask, add 5mL (25%) nitric acid to the measuring flask, and add deionized water to the volume. (2) Component analysis tests were conducted using the calibration curve method. According to the above method, the single-crystal sodium ion battery positive electrode material C1 has the chemical formula Na 0.87 Ni 0.32 Mn 0.32 Fe 0.33 B 0.01 Al 0.02 It was measured to be O2.

[0073] 2) Specific surface area The measurement was performed according to the national standard GB / T19587-2006, the method for measuring the specific surface area of ​​solids by gas adsorption BET method. Analytical instrument: Tristar II 3020 fully automatic specific surface area and pore distribution measuring device, Test parameters: adsorbate N2, 99.999%, coolant liquid nitrogen, P0 actual measurement, volume measurement mode, adsorption pressure deviation 0.05 mmHg, equilibration time 5 s, relative pressure point selection P / P0: 0.05, 0.1, 0.15, 0.2, 0.25, 0.30, Sample preparation: An empty sample tube and plug were weighed, and 3.8-4.2 g of sample was added to a 9.5 mm specific surface area sample tube with a 3 / 8 inch ball valve. The tube was heated to 200 °C using a FlowPrep 060 degassing station, purged with inert gas, and degassed for 0.5 h. The tube was then removed and cooled to room temperature. The combined sample tube, plug, and sample mass, M2, was weighed. The sample mass, M = M2 - M1, was then measured on-machine and the BET value recorded. The results are shown in Table 3.

[0074] 3) Particle size The particle size distribution was measured according to the national standard GB / T19077-2016 laser diffraction method, and the results are shown in Table 3. Testing instrument: Malvern, Master Size 2000 laser particle size analyzer. Test procedure: 1g of powder was weighed and added to 60ml of pure water, and then externally ultrasonicated for 5 minutes. The sample was then injected into the sample injector, the test was performed, and the test data was recorded. Test conditions: The test principle was Mie theory (light scattering), the detection angle was 0-135°, the external ultrasonic intensity was 40KHz, 180W, the particle refractive index was 1.692, the particle absorption coefficient was 1, the sample test time was 6 seconds, the background test snap count was 6,000 times, and the light blocking rate was 8-12%.

[0075] 4) pH value The measurement was performed using a PHSJ-3F lightning-magnetic pH meter. The specific method was as follows: 5g ± 0.05g of sample was accurately weighed, and deionized water was added in a material / water ratio of 1:9 by mass to form a 10% suspension. The magnetic particles were added and placed on the magnetic stirrer tray. The magnetic stirrer was rotated at 880 r / min and stirred for 5 minutes. The mixed solution was filtered using qualitative filter paper and a funnel, and then placed in a thermostatic water bath set at 25°C and thermostatically filtered for 20 ± 5 minutes. The electrode was then rinsed with the sample solution. After rinsing, the electrode and temperature sensor were inserted into the sample solution. The pH value was recorded when the reading stabilized and the temperature reached 25°C. The results are shown in Table 3.

[0076] 5) XRD test XRD testing of the sodium ion cathode materials in the examples of the present invention employed an X'Pert PRO MPD analyzer. Test principle: The Bragg equation reflects the relationship between the direction of diffraction rays and crystal structure. For diffraction to occur, the Bragg equation must be satisfied: 2dsinθ=nλ (d: crystal plane spacing, θ: Bragg angle, λ: X-ray wavelength, n: reflection series). When X-rays are irradiated onto a sample, the scattered X-rays from each atom in the crystal interfere with each other, generating strong X-ray diffraction rays in a specific direction. When X-rays are irradiated onto a sample from different angles, diffraction occurs at different crystal planes, and the detector receives the number of diffracted photons reflected from the crystal planes, thereby obtaining a spectrum showing the relationship between angle and intensity. Test conditions: light pipe is Cu target material, wavelength is 1.54060, Be window, incident light path: Soller slit 0.04 rad, divergence slit 1 / 2°, light shielding plate 10 mm, anti-scattering slit 1°, diffraction light path: anti-scattering slit 8.0 mm, Soller slit 0.04 rad, large Ni filter, scanning range 10~90°, scanning step 0.013°, dwell time for each step 30.6 s, voltage 40 kV, current 40 mA. Powder sample preparation: Use a clean sampling spoon to place the powder into the groove of a glass slide (for large particle samples, the powder needs to be polished to <50 μm). Place one side of the blade (>20 mm) on the surface of the glass slide and slightly lift the other side (included angle <10°). Use the edge of the blade to scrape the surface of the powder sample flat, rotate the glass slide 90°, and scrape it flat again. Repeat this process in both directions several times until there is no texture on the surface of the sample. Remove excess powder around the glass slide and place it in the powder diffraction analyzer. Sample analysis: The sample file was opened using the High-Score Plus analysis software. The background was determined, peak detection was selected, peak confirmation was performed, and then iterative fitting was performed. The Williamson-Hall plot was recorded to calculate the grain size. The corresponding phase was selected, phase matching and unit cell refinement were performed, and the half-width of the (110) diffraction peak at a diffraction angle 2θ of approximately 64.9° was recorded. The results are shown in Table 3.

[0077] 6) Moisture The measurement was performed in accordance with the GB / T 11133-2015 Karl Fischer coulometric titration method. 899 Coulometer + 885 Compact Oven SC coulometer was used to test. 0.5-0.8g of sample was weighed using a water bottle. The accuracy was within 0.0001g. The gas flow rate was 50-60ml / min, the heating temperature was 170℃, the initial drift was ≦10μg / min, the final drift was 20μg / min, and the extraction time was 400s. The test results were accurate to one decimal place. The results are shown in Table 3.

[0078] 7) Green density [1] The specimen circular mold was placed on the stage of an electronic pressure tester, and the pressure was slowly increased manually up to 1000 kg, after which the displacement and deformation were zero. [2] Place the sample bag on an electronic balance, subtract the weight of the container, and use a spoon (5.0000±0.1000) to place the powder into a circular mold. Shake gently to flatten it, and then place the upper pad of the mold on the sample. Be careful that both pads face the non-cut surface of the sample to prevent spillage. [3] After filling the sample, the mold was placed on the stage of the electronic pressure tester, and a program was edited to increase the pressure to 8000 kg at a rate of 5 mm / min, hold the voltage constant for 30 s, and then reduce the pressure to zero. [4] When the sample was pressurized to 8000±10 kg (approximately 15-25 s after the pressure reached 8000 kg), the pressure on the sample was recorded and the sample height h was read, with an accuracy of 0.001 cm. [5] After the reading was completed, the stage of the electronic pressure tester was manually lowered and the sample was removed using the remover. [6] After removing the sample, the inside of the sample mold was cleaned with alcohol-soaked clean paper to ensure that the inside of the mold was clean, and the experiment was completed. [7] Calculations were made using the formula below, and the results are shown in Table 3.

number

[0079] The single crystal sodium ion battery cathode material of Example 1 was subjected to SEM examination, as shown in Figure 1, which reveals that the material is single crystal particles and the topography is polygonal, layered sheets.

[0080] The single-crystal sodium-ion battery cathode material of Example 1 was thoroughly mixed with the binder polyvinylidene fluoride (PVDF) and conductive carbon black (SP) in a weight ratio of 90:5:5, and stirred to form a uniform slurry. This was then applied to an aluminum foil current collector, dried, and cold-pressed to form a tab. The tab was subjected to SEM examination, as shown in Figure 9. Figure 9 shows that the material is still single-crystal particles, and no cracks have occurred on the surface of the material particles.

[0081] Example 2 Sodium carbonate, manganese carbonate, nickel carbonate, iron trioxide, and copper oxide were weighed out to a total weight of 1.46 kg with an element molar ratio of Na:Mn:Ni:Fe:Cu = 0.79:0.30:0.18:0.30:0.22, and mixed in an ultra-high speed multi-function mixer at a rotation speed of 4000 r / min for 20 minutes. The homogeneously mixed materials were placed in a muffle furnace and heated at 905°C for 12 hours in an air atmosphere. After natural cooling, they were pulverized in an air flow mill at a pulverization pressure of 0.58 MPa to obtain semi-finished products. 1.08 kg of the above semi-finished product and 0.005 kg of titanium oxide were weighed and added to a ball mill can and ball milled at 35 Hz for 20 minutes. The homogeneously mixed material was then placed in a muffle furnace and heated at 400°C in an air atmosphere for 3 hours, then naturally cooled, and then crushed using an airflow crusher at a crushing pressure of 0.54 MPa and sieved to obtain single-crystal sodium-ion battery positive electrode material C2.

[0082] Using the component analysis method in Example 1, the single-crystal sodium ion battery positive electrode material C2 was found to have the chemical formula Na 0.79 Ni 0.18 Mn 0.295 Fe 0.30 Cu 0.22 Ti 0.005 It was measured to be O2.

[0083] The above positive electrode material was tested using the method in Example 1, and the test results are shown in Table 3.

[0084] The single crystal sodium ion battery cathode material of Example 2 was subjected to SEM examination, as shown in Figure 2, which shows that the material is single crystal particles and the topography is polygonal, layered sheets.

[0085] The single-crystal sodium-ion battery cathode material of Example 2 was thoroughly mixed with the binder polyvinylidene fluoride (PVDF) and conductive carbon black (SP) in a weight ratio of 90:5:5, and stirred to form a uniform slurry. This was then applied to an aluminum foil current collector, dried, and cold-pressed to form a tab. The tab was subjected to SEM examination, as shown in Figure 10. Figure 10 shows that the material is still single-crystal particles, and no cracks have occurred on the surface of the material particles.

[0086] Example 3 Sodium carbonate, manganese trioxide, nickel oxalate, ferrous oxalate, and zinc oxide were weighed out to a total weight of 1.844 kg with an element molar ratio of Na:Mn:Ni:Fe:Zn = 0.85:0.30:0.18:0.30:0.22, and mixed in an ultra-high speed multi-function mixer at a rotation speed of 3500 r / min for 30 minutes. The homogeneously mixed materials were placed in a muffle furnace and heated at 910°C for 10 hours in an air atmosphere. After natural cooling, they were pulverized in an airflow pulverizer at a pulverization pressure of 0.63 MPa to obtain semi-finished products. 1.11 kg of the above semi-finished product and 0.0025 kg of magnesium oxide were weighed and added to a ball mill can and ball milled at 45 Hz for 15 minutes. The homogeneously mixed material was placed in a muffle furnace and heated at 500°C in an air atmosphere for 5 hours, then naturally cooled. The mixture was then pulverized using an airflow pulverizer at a pulverization pressure of 0.56 MPa and sieved to obtain single-crystal sodium-ion battery positive electrode material C3.

[0087] Using the component analysis method in Example 1, the single-crystal sodium ion battery positive electrode material C3 was found to have the chemical formula Na 0.88 Ni 0.18 Mn 0.30 Fe 0.297 Zn 0.22 Mg 0.003 It was measured to be O2.

[0088] The above positive electrode material was tested using the method in Example 1, and the test results are shown in Table 3.

[0089] The single crystal sodium ion battery cathode material of Example 3 was subjected to SEM examination, as shown in FIG. 3, which shows that the material is single crystal particles and the topography is polygonal, layered sheets.

[0090] The single-crystal sodium-ion battery cathode material of Example 3 was thoroughly mixed with the binder polyvinylidene fluoride (PVDF) and conductive carbon black (SP) in a weight ratio of 90:5:5, and stirred to form a uniform slurry. This was then applied to an aluminum foil current collector, dried, and pressed to form a tab. The tab was subjected to SEM examination, as shown in Figure 11. Figure 11 shows that the material is still single-crystal particles, and no cracks have occurred on the surface of the material particles.

[0091] Example 4 Sodium carbonate, manganese trioxide, nickel oxalate, ferrous oxalate, and zinc oxide were weighed out to a total weight of 1.844 kg with an element molar ratio of Na:Mn:Ni:Fe:Zn = 0.88:0.30:0.18:0.30:0.22. The materials were mixed in an ultra-high-speed multi-function mixer at 3500 r / min for 30 minutes. The homogeneously mixed materials were placed in a muffle furnace and heated to 920°C in an air atmosphere for 15 hours. The mixture was then naturally cooled and crushed in an air-flow crusher at a crushing pressure of 0.68 MPa to obtain a semi-finished product.

[0092] Weigh out 0.025 kg of aluminum nitrate, and mix the weighed aluminum nitrate with pure water in a mass ratio of 1:3 to prepare an aluminum nitrate solution for use. Weigh out 1.11 kg of the above semi-finished product, add it to water and stir for 10 minutes, add the blended aluminum nitrate solution, continue stirring for 10 minutes, suction filter, dry, and put the dried material into a muffle furnace and keep it at 600 ° C in an air atmosphere for 6 hours, then naturally cool, and use an airflow mill to pulverize it under a pulverizing pressure of 0.60 MPa, sieve it, and obtain single-crystal sodium ion battery positive electrode material C4.

[0093] Using the component analysis method in Example 1, the single-crystal sodium ion battery positive electrode material C4 was found to have the chemical formula Na 0.88 Ni 0.18 Mn0.297 Fe 0.291 Zn 0.22 Al 0.012 It was measured to be O2.

[0094] The above positive electrode material was tested using the method in Example 1, and the test results are shown in Table 3.

[0095] The single crystal sodium ion battery cathode material of Example 4 was subjected to SEM examination, as shown in FIG. 4, which shows that the material is single crystal particles and the topography is polygonal, layered sheets.

[0096] The single-crystal sodium-ion battery cathode material of Example 4 was thoroughly mixed with the binder polyvinylidene fluoride (PVDF) and conductive carbon black (SP) in a weight ratio of 7:2:1, and stirred to form a uniform slurry. This was then applied to an aluminum foil current collector, dried, and pressed to form a tab. The tab was subjected to SEM examination, as shown in Figure 12. This shows that the material is still single-crystal particles, and no cracks have occurred on the surface of the material particles.

[0097] Example 5 The molar ratio of elements was Na:Mn:Ni:Fe:Al = 0.81:0.33:0.33:0.33:0.01, and the total weight was 1.56 kg. The corresponding weights of sodium carbonate, manganese carbonate, nickel carbonate, iron trioxide, and aluminum oxide were weighed and mixed in an ultra-high-speed multi-function mixer at a rotation speed of 2800 r / min for 30 minutes. The homogeneously mixed material was placed in a muffle furnace and heated at 930°C in an air atmosphere for 10 hours, then naturally cooled. The material was then pulverized in an airflow pulverizer at a pulverization pressure of 0.65 MPa to obtain a semi-finished product. 1.068 kg of the above semi-finished product and 0.0074 kg of boron oxide were weighed, added to a ball mill can, and ball milled at 40 Hz for 10 minutes. The homogeneously mixed material was then placed in a muffle furnace and heated at 500°C in an air atmosphere for 3 hours, then naturally cooled. The mixture was then pulverized using an airflow pulverizer at a pulverization pressure of 0.56 MPa and sieved to obtain single-crystal sodium-ion battery positive electrode material C5.

[0098] Using the component analysis method in Example 1, the single-crystal sodium ion battery positive electrode material C5 was found to have the chemical formula Na 0.81 Ni 0.33 Mn 0.33 Fe 0.31 Al 0.01 B 0.02 It was measured to be O2.

[0099] The above positive electrode material was tested using the method in Example 1, and the test results are shown in Table 3.

[0100] The single crystal sodium ion battery cathode material of Example 5 was subjected to SEM examination, as shown in FIG. 5, which shows that the material is single crystal particles and the topography is polygonal, layered sheets.

[0101] The single-crystal sodium-ion battery cathode material of Example 5 was thoroughly mixed with the binder polyvinylidene fluoride (PVDF) and conductive carbon black (SP) in a weight ratio of 7:2:1, and stirred to form a uniform slurry. This was then applied to an aluminum foil current collector, dried, and pressed to form a tab. The tab was subjected to SEM examination, as shown in Figure 13. Figure 13 shows that the material is still single-crystal particles, and no cracks have occurred on the surface of the material particles.

[0102] Example 6 Sodium carbonate, manganese carbonate, nickel carbonate, ferrous oxalate, and zinc oxide were weighed out to a total weight of 1.77 kg with an element molar ratio of Na:Mn:Ni:Fe:Zn = 0.84:0.34:0.25:0.30:0.11. The materials were mixed in an ultra-high-speed multi-function mixer at 3000 r / min for 30 minutes. The homogeneously mixed materials were placed in a muffle furnace and heated to 980°C in an air atmosphere for 9 hours. The mixture was then naturally cooled and crushed in an air-flow crusher at a crushing pressure of 0.66 MPa to obtain a semi-finished product.

[0103] 1.086 kg of the above semi-finished product and 0.048 kg of niobium pentoxide were weighed and added to a ball mill can and ball milled at 40 Hz for 20 minutes. The homogeneously mixed material was placed in a muffle furnace and kept at 600°C in an air atmosphere for 7 hours, then naturally cooled. The mixture was then pulverized using an air flow pulverizer at a pulverization pressure of 0.58 MPa and sieved to obtain single-crystal sodium-ion battery positive electrode material C6.

[0104] Using the component analysis method in Example 1, the single-crystal sodium ion battery positive electrode material C6 was found to have the chemical formula Na 0.84 Ni 0.25 Mn 0.34 Fe 0.295 Zn 0.11 Nb 0.005 It was measured to be O2.

[0105] The above positive electrode material was tested using the method in Example 1, and the test results are shown in Table 3.

[0106] The single crystal sodium ion battery cathode material of Example 6 was subjected to SEM examination, as shown in FIG. 6, which shows that the material is single crystal particles and the topography is polygonal, layered sheets.

[0107] The single-crystal sodium-ion battery cathode material of Example 6 was thoroughly mixed with the binder polyvinylidene fluoride (PVDF) and conductive carbon black (SP) in a weight ratio of 7:2:1, and stirred to form a uniform slurry. This was then applied to an aluminum foil current collector, dried, and pressed to form a tab. The tab was subjected to SEM examination, as shown in Figure 14. Figure 14 shows that the material is still single-crystal particles, and no cracks have occurred on the surface of the material particles.

[0108] Example 7 Sodium carbonate, manganese carbonate, and iron trioxide were weighed out to a total weight of 1.61 kg with an element molar ratio of Na:Mn:Fe = 0.84:0.5:0.5, and mixed for 25 minutes at 3700 r / min in an ultra-high-speed multi-function mixer. The homogeneously mixed materials were placed in a muffle furnace and heated to 875°C in an air atmosphere for 9 hours, then naturally cooled. They were then pulverized in an airflow pulverizer at a pulverization pressure of 0.66 MPa to obtain a semi-finished product.

[0109] 1.072 kg of the above semi-finished product and 0.045 kg of zirconium oxide were weighed and added to a ball mill can and ball milled at 45 Hz for 15 minutes. The homogeneously mixed material was placed in a muffle furnace and kept at 730°C in an air atmosphere for 7 hours, then naturally cooled. The mixture was then pulverized using an airflow pulverizer at a pulverization pressure of 0.58 MPa and sieved to obtain single-crystal sodium-ion battery positive electrode material C7.

[0110] Using the component analysis method in Example 1, the single-crystal sodium ion battery positive electrode material C7 was found to have the chemical formula Na 0.84 Mn 0.497 Fe 0.5 Zr 0.003 It was measured to be O2.

[0111] The single crystal sodium ion battery cathode material of Example 7 was subjected to SEM examination, as shown in FIG. 7, which shows that the material is single crystal particles and the topography is polygonal, layered sheets.

[0112] The single-crystal sodium-ion battery cathode material of Example 7 was thoroughly mixed with the binder polyvinylidene fluoride (PVDF) and conductive carbon black (SP) in a weight ratio of 7:2:1, and stirred to form a uniform slurry. This was then applied to an aluminum foil current collector, dried, and pressed to form a tab. The tab was subjected to SEM examination, as shown in Figure 15. Figure 15 shows that the material is still single-crystal particles, and no cracks have occurred on the surface of the material particles.

[0113] Example 8 Sodium carbonate, manganese carbonate, nickel carbonate, ferrous oxalate, and titanium dioxide were weighed out to a total weight of 1.79 kg with an element molar ratio of Na:Mn:Ni:Fe:Ti = 0.91:0.1:0.42:0.32:0.16 and mixed for 35 minutes at 3300 r / min in an ultra-high-speed multi-function mixer. The homogeneously mixed materials were placed in a muffle furnace and heated to 890°C in an oxygen atmosphere for 10 hours. After natural cooling, they were pulverized in an airflow pulverizer at a pulverization pressure of 0.62 MPa to obtain a semi-finished product.

[0114] Weigh out 0.025 kg of aluminum nitrate, and mix the weighed aluminum nitrate with pure water in a mass ratio of 1:3 to prepare an aluminum nitrate solution for use. Weigh out 1.072 kg of the above semi-finished product, add it to water and stir for 10 minutes, add the blended aluminum nitrate solution, continue stirring for 10 minutes, suction filter, dry, and put the dried material into a muffle furnace and keep it at 550 ° C in an oxygen atmosphere for 4 hours, then naturally cool, and use an airflow mill to pulverize it under a pulverizing pressure of 0.60 MPa, sieve it, and obtain single-crystal sodium ion battery positive electrode material C8.

[0115] Using the component analysis method in Example 1, the single-crystal sodium ion battery positive electrode material C8 was found to have the chemical formula Na 0.91 Ni 0.42 Mn 0.1 Fe 0.308 Ti 0.16 Al 0.012 It was measured to be O2.

[0116] The single crystal sodium ion battery cathode material of Example 8 was subjected to SEM examination, as shown in FIG. 8, which shows that the material is single crystal particles and the topography is polygonal, layered sheets.

[0117] The single-crystal sodium-ion battery cathode material of Example 8 was thoroughly mixed with the binder polyvinylidene fluoride (PVDF) and conductive carbon black (SP) in a weight ratio of 7:2:1, and stirred to form a uniform slurry. This was then applied to an aluminum foil current collector, dried, and pressed to form a tab. The tab was subjected to SEM examination, as shown in Figure 16. Figure 16 shows that the material is still single-crystal particles, and no cracks have occurred on the surface of the material particles.

[0118] Example 9 Sodium carbonate, manganese trioxide, nickel oxalate, ferrous oxalate, and zinc oxide were weighed out to a total weight of 1.844 kg with an elemental molar ratio of Na:Mn:Ni:Fe:Zn = 0.88:0.30:0.18:0.30:0.22. The materials were mixed in an ultra-high-speed multi-function mixer at 3500 r / min for 30 minutes. The homogeneously mixed materials were placed in a muffle furnace and heated to 900°C in an air atmosphere for 10 hours. The mixture was then allowed to cool. The mixture was then crushed in an airflow crusher at a crushing pressure of 0.63 MPa and sieved to obtain single-crystalline sodium-ion battery cathode material C9.

[0119] Using the component analysis method in Example 1, the single-crystal sodium ion battery positive electrode material C9 was found to have the chemical formula Na 0.88 Ni 0.18 Mn 0.30 Fe 0.30 Zn 0.22 It was measured to be O2.

[0120] The above positive electrode material was tested using the method in Example 1, and the test results are shown in Table 3.

[0121] The single crystal sodium ion battery cathode material of Example 9 was subjected to SEM examination, as shown in FIG. 17, which shows that the material is single crystal particles and the topography is polygonal, layered sheets.

[0122] The single-crystal sodium-ion battery cathode material of Example 9 was thoroughly mixed with the binder polyvinylidene fluoride (PVDF) and conductive carbon black (SP) in a weight ratio of 7:2:1, and stirred to form a uniform slurry. This was then applied to an aluminum foil current collector, dried, and pressed to form a tab. The tab was subjected to SEM examination, as shown in Figure 18. Figure 18 shows that the material is still single-crystal particles, and no cracks have occurred on the surface of the material particles.

[0123] [Table 3]

[0124] As can be seen from Table 3, in the powder X-ray diffraction spectra (XRD) of the single crystal sodium ion battery positive electrode materials produced in Examples 1 to 8, the full width at half maximum (FWHM) (110) of the (110) diffraction peak at a diffraction angle 2θ of approximately 64.9° was 0.15 to 0.27, the water mass content was 1200 ppm or less, the pH was less than 12.60 in all cases, and the specific surface area was 0.31 to 0.69 m 2 / g, and particle size D V 50 is 3.4 to 10.2 μm, and the green density is 2.95 to 3.83 g / cm 3 Example 9 was not subjected to any coating treatment and had a water content of 2145 ppm by mass, which is much greater than 1500 ppm, and a pH of 12.92, which is greater than 12.6.

[0125] (Experimental Example 1) Fabrication and performance evaluation of sodium-ion batteries.

[0126] CR2430 button cell batteries are manufactured according to the following method. Positive electrode preparation: The positive electrode materials for single-crystal sodium-ion batteries prepared in Examples 1 to 9 of the present invention, polyvinylidene fluoride (PVDF) as a binder, and conductive carbon black (SP) were thoroughly mixed in a weight ratio of 7:2:1, and stirred to form a uniform slurry. The slurry was then applied to an aluminum foil current collector, dried, and pressed to form tabs, which were designated as PE-C1, PE-C2, PE-C3, PE-C4, PE-C5, PE-C6, PE-C7, PE-C8, and PE-C9. The pressed positive electrode tab was punched out, weighed, and sintered, and then assembled into a battery in a vacuum glove box. First, the bottom of the button battery case was placed on top of it, and then a 2.5mm foam nickel sheet and a negative electrode metallic sodium sheet (manufacturer: Shenzhen Youken Technology Co., Ltd.) were placed on top of it. 0.5g of electrolyte was poured into the battery in an environment with a relative humidity of less than 1.5%. The electrolyte was a 1 mol / L sodium hexafluorophosphate solution, made from a 1:1:1 mixed solvent of ethylene carbonate (EC), diethyl carbonate (DEC), and dimethyl carbonate (DMC). A separator and a positive electrode tab were then placed on the battery case, and the battery case was sealed to obtain button batteries with model numbers CR2430. These batteries are designated BA-C1, BA-C2, BA-C3, BA-C4, BA-C5, BA-C6, BA-C7, BA-C8, and BA-C9.

[0127] The battery was subjected to a performance test on a battery test system according to the following method, and the results are shown in Table 4. 1) Capacity test The manufactured button cell battery was mounted on a test stand and the test program was started. The test temperature was set to 25°C, the battery was left standing for 4 hours, the battery was charged at a constant current of 0.1C to 4.0V, the battery was paused, the battery was left standing, and the battery was discharged at a constant current of 0.1C to 2.0V, and the capacity at the current and voltage was obtained. 2) Cycle test The battery that has undergone the above capacity test is mounted on a test stand, and the test program is started. The set steps are: test temperature is set to 45°C, left to stand for 4 hours, constant current charging at 0.5C to 4.0V, constant voltage charging at 4.0V for 2 hours, left to stand for 5 minutes, and then constant current discharging at 0.5C to a cutoff voltage of 2.0V, left to stand for 5 minutes. The previous constant current charging start step is repeated to perform a cycle test, and the capacity retention rate according to the number of cycles can be obtained.

[0128] [Table 4]

[0129] As can be seen from Table 4, the sodium ion batteries manufactured using the positive electrode materials for single crystal sodium ion batteries manufactured in Examples 1 to 8 had capacities of 115.9 to 164.0 mAh / g at a current of 0.1 C and a voltage of 4.2 V (cut-off voltage: 2.0 V), and had capacity retention rates of 80.2 to 90.5% after 50 cycles under conditions of 4.0 V to 2.0 V and 0.5 C / 0.5 C. Example 9, which was not subjected to a coating treatment, had a capacity retention rate of only 74.84% after 50 cycles under conditions of 4.0 V to 2.0 V and 0.5 C / 0.5 C. Figure 20 also shows that the capacity retention rates during cycle testing of the sodium ion batteries manufactured using the positive electrode materials for single crystal sodium ion batteries manufactured in Examples 1 to 8 were clearly superior to that of Example 9.

[0130] After 50 cycles of battery BA-C1, the battery was disassembled and the positive electrode tab was taken out for SEM examination, as shown in Figure 19. From Figure 19, it can be seen that the single crystal particles remain intact even after cycling, with no particle cracks.

[0131] The above description is merely a preferred embodiment of the present invention and does not limit the present invention in any way. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention must be included in the protection scope of the present invention.

[0132] (Addendum) (Appendix 1) A positive electrode material for a single crystal sodium ion battery, The positive electrode material for the single crystal sodium ion battery contains elements having a composition represented by Chemical Formula 1, where Chemical Formula 1 is Na 1+a Ni 1-x-y-z-c Mn x Fe y M z N c O2, where -0.40 ≦ a ≦ 0.25, 0.08 ≦ x ≦ 0.5, 0.05 ≦ y ≦ 0.5, 0 ≦ z < 0.26, 0 < c < 0.1, M is a doping element, and N is a coating element, Both M and N are selected from one or more of the elements Ti, Zn, Co, Mn, Al, Zr, Y, Ca, Li, Rb, Cs, W, Ce, Mo, Ba, Mg, Ta, Nb, V, Sc, Sr, B, F, P, or Cu, A positive electrode material for a single crystal sodium ion battery, characterized by the above.

[0133] (Appendix 2) -0.40 ≦ a ≦ 0, 0.15 ≦ x ≦ 0.5, 0.15 ≦ y ≦ 0.5, A positive electrode material for a single crystal sodium ion battery according to Appendix 1, characterized by the above.

[0134] (Appendix 3) M is selected from one or more of Zn, Ti, Co, Al, Zr, Y, Ca, Li, Rb, Cs, W, Ce, Mo, Ba, Mg, Ta, Nb, V, Sc, Sr, B, F, P, or Cu, A positive electrode material for a single crystal sodium ion battery according to Appendix 1, characterized by the above.

[0135] (Appendix 4) M is one or more of Zn, Al, B, Ti, Ca, Y, Mg, Nb, Zr, or Cu, A positive electrode material for a single crystal sodium ion battery according to Appendix 1, characterized by the above.

[0136] (Appendix 5) -0.40≦a≦0.25, 0.08≦x≦0.5, 0.05≦y≦0.5, 0 <c<0.1、0≦z≦0.13である、 2. The positive electrode material for a single crystal sodium ion battery according to claim 1,

[0137] (Appendix 6) The N is one or more selected from Al, Ti, Co, Mn, Y, B, F, P, Nb, Zr, W, Sr, and Mg. 2. The positive electrode material for a single crystal sodium ion battery according to claim 1,

[0138] (Appendix 7) The N is one or more of Al, Ti, B, Nb, and Mg, 2. The positive electrode material for a single crystal sodium ion battery according to claim 1,

[0139] (Appendix 8) -0.40≦a≦0.25, 0.08≦x≦0.5, 0.05≦y≦0.5, 0≦z<0.26, 0 <c<0.05である、 2. The positive electrode material for a single crystal sodium ion battery according to claim 1,

[0140] (Appendix 9) The single-crystal sodium-ion battery positive electrode material has a microscopic topography that is single-crystal topography when viewed under a scanning electron microscope, and the shape of the single-crystal topography particles is one or more of a spherical shape, a pseudo-spherical shape, a polygonal shape, or a layered sheet shape. 2. The positive electrode material for a single crystal sodium ion battery according to claim 1,

[0141] (Appendix 10) In the powder X-ray diffraction spectrum (XRD) of the single crystal sodium ion battery positive electrode material, the full width at half maximum (FWHM) (110) of the (110) diffraction peak at a diffraction angle 2θ of approximately 64.9° is 0.08 to 0.35. 10. The positive electrode material for a single crystal sodium ion battery according to any one of appendices 1 to 9,

[0142] (Appendix 11) The green density of the positive electrode material for single crystal sodium ion batteries under a pressure of 7000 to 9000 kg is 2.8 to 4.2 g / cm 3 That is, 10. The positive electrode material for a single crystal sodium ion battery according to any one of appendices 1 to 9,

[0143] (Appendix 12) The water mass content of the positive electrode material for a single crystal sodium ion battery is less than 1500 ppm, and / or the pH value of the positive electrode material for a single crystal sodium ion battery is within 12.6. 10. The positive electrode material for a single crystal sodium ion battery according to any one of appendices 1 to 9,

[0144] (Appendix 13) The specific surface area of ​​the positive electrode material for the single crystal sodium ion battery is 0.35 to 1.2 m 2 / g, and / or the particle size D of the positive electrode material for a single crystal sodium ion battery V 50 is 2.00 to 16.0 μm, 10. The positive electrode material for a single crystal sodium ion battery according to any one of appendices 1 to 9,

[0145] (Appendix 14) Step (1) of mixing raw materials including a sodium source compound, a manganese source compound, and an iron source compound, optionally adding a nickel source compound and an M source compound, and then sintering the mixture for the first time and pulverizing the mixture to obtain a semi-finished product; and step (2) of mixing the semi-finished product obtained in step (1) with the raw material of the N source compound, followed by a second sintering and pulverization to obtain a single-crystal sodium-ion battery positive electrode material. 10. A method for producing a positive electrode material for a single crystal sodium ion battery according to any one of appendices 1 to 9.

[0146] (Appendix 15) the first sintering temperature in step (1) is 860 to 990°C, the second sintering temperature in step (2) is 350 to 900°C, and / or the grinding pressure in steps (1) and (2) is both 0.1 to 1 MPa; 15. The method of claim 14,

[0147] (Appendix 16) The sodium source compound comprises a salt and / or hydroxide containing elemental sodium, and / or The manganese source compound includes one or more of an oxide, hydroxide, or salt containing manganese element, and / or The nickel source compound includes one or more of an oxide, a hydroxide, or a salt containing nickel element, and / or The iron source compound includes one or more of an oxide, a hydroxide, or a salt containing an iron element, and / or The M source compound includes an oxide and / or a salt containing the M element, and / or The N source compound includes an oxide and / or a salt containing N element. 15. The method of claim 14,

[0148] (Appendix 17) The active material is a positive electrode material for a single crystal sodium ion battery according to any one of Supplementary Notes 1 to 13. A positive electrode for a sodium ion battery.

[0149] (Appendix 18) Supplementary Note 17: A sodium-ion battery characterized by:

Claims

1. A single-crystal sodium-ion battery positive electrode material, comprising: The single-crystal sodium-ion battery positive electrode material contains elements having a composition represented by Chemical Formula 1, The formula 1 is Na １＋ａ Ni １－ｘ－ｙ－ｚ－ｃ Mn ｘ Fe ｙ M ｚ N ｃ O ２ wherein −0.40≦a≦0.25, 0.08≦x≦0.5, 0.05≦y≦0.5, 0<z<0.26, 0<c<0.1, M is a doping element, N is a coating element, and 1−x-y-z-c>0, the coating element N forms a coating layer of the positive electrode material; Each of M and N is one or more elements selected from Ti, Zn, Co, Al, Zr, Y, Ca, Li, Rb, Cs, W, Ce, Mo, Ba, Mg, Ta, Nb, V, Sc, Sr, B, F, P, and Cu; In the powder X-ray diffraction spectrum (XRD) of the single crystal sodium ion battery positive electrode material, the full width at half maximum (FWHM) (110) of the (110) diffraction peak at a diffraction angle 2θ of around 64.9° is 0.08 to 0.

35. A positive electrode material for a single crystal sodium ion battery.

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