Sodium ion positive electrode material, method for producing the same, use thereof, sodium ion battery, sodium ion battery pack, and device

Abstract

The present invention relates to the field of sodium ion battery technology, and discloses a sodium ion positive electrode material and its manufacturing method and use, a sodium ion battery, a sodium ion battery pack, and an apparatus. The sodium ion positive electrode material includes a matrix and a coating layer coated on the matrix, The matrix has a composition shown in Formula I, Na 1-x [Ni y Mn z M u ]Ti v O2 formula I The coating layer has a composition shown in Formula II, Na 2-β Ti 6-α M′ α O 13 Formula II The sodium ion positive electrode material has the characteristics of high ionic and electronic conductivity, strong structural stability and strong chemical stability, and when the composite positive electrode material is used in a sodium ion battery, it can effectively improve the electrical and chemical performance of the battery.

Description

Technical Field

[0001] The present invention relates to the field of sodium-ion battery technology, specifically to sodium-ion cathode materials and their manufacturing methods, uses, sodium-ion batteries, sodium-ion battery packs, and devices.

Background Art

[0002] The explosive development of new energy vehicles and the large-scale storage market, along with the significant increase in the sales of lithium-ion batteries, have posed a severe challenge to the global lithium resource supply. Compared with lithium resources, the content of sodium resources in the earth's crust structure reaches 2.4 wt%, and the distribution is wide, much higher than 0.0065 wt% of lithium resources. Therefore, in recent years, sodium-ion batteries have become an energy storage system that has been intensively developed in the new energy industry.

[0003] The cathode material in a sodium-ion battery is a very important key material, and currently mainly includes systems such as metal oxides, polyanion compounds, Prussian blue materials, and organic materials. The metal oxide-based cathode material has advantages such as a high voltage platform, high discharge capacity, and high powder compaction, and is a battery material with high development potential. The charge and discharge process of the metal oxide cathode material is an intercalation / deintercalation reaction. Due to the large radius of sodium ions, the volume expansion and contraction changes during the charge and discharge process are too large, resulting in poor cycle performance and also having an adverse impact on the battery safety performance.

[0004] Therefore, there is an urgent need for a new composite cathode material for sodium-ion batteries.

Summary of the Invention

Problems to be Solved by the Invention

[0005] The present invention aims to provide a sodium-ion cathode material, its manufacturing method, usage, a sodium-ion battery, a sodium-ion battery pack, and a device, in order to overcome the problems existing in the conventional sodium-ion battery cathode material, such as low ionic conductivity, poor structural stability, and poor chemical stability. The sodium-ion cathode material has characteristics such as high ionic and electronic conductivity, strong structural stability, and strong chemical stability. At the same time, when the composite cathode material is used in a sodium-ion battery, the electrochemical performance of the battery can be effectively improved.

Means for Solving the Problems

[0006] To achieve the above object, a first aspect of the present invention provides a sodium-ion cathode material, which includes a matrix and a coating layer coated on the matrix. The matrix has a composition represented by Formula I. Na 1-x [Ni y Mn z M u Ti v O2 Formula I In the formula, -0.4 ≦ x ≦ 0.4, 0.2 ≦ y ≦ 0.6, 0.1 ≦ z ≦ 0.5, 0.1 ≦ u ≦ 0.5, 0 ≦ v ≦ 0.02, y + z + u + v = 1, and M is selected from at least one of Fe, Mg, Al, Cu, Zn, Zr, Nb, Co, Y, V, Sc, Cr, W, La, Mo, Os, Pr, Re, Ru, Sr, Sm, and Ta. The coating layer has a composition represented by Formula II. Na 2-β Ti 6-α M′ α O 13 Formula II In the formula, 0 ≦ α < 0.6, -2 ≦ β < 1, and M′ is selected from at least one of Li, Mg, Fe, Al, Ga, In, Ge, Y, Sc, and Zr.

[0007] A second aspect of the present invention provides a manufacturing method of a sodium-ion cathode material, and the manufacturing method includes the following steps.

[0008] (1) Perform a first mixing on the first sodium source, a selectable M′ source, a titanium source, and a solvent to obtain a first slurry. Sequentially perform a first drying and a first sintering on the first slurry to obtain a first sintered product. Sequentially perform crushing and drying on the obtained first sintered product to obtain a coating layer. Here, the coating layer has a composition represented by Formula II, Na 2-β Ti 6-α M′ α O 13 Formula II In the formula, 0 ≦ α < 0.6, -2 ≦ β < 1, and M′ is selected from at least one of Li, Mg, Fe, Al, Ga, In, Ge, Y, Sc, and Zr. (2) Perform a second mixing on the second sodium source, a nickel source, a manganese source, an M source, and a selectable titanium source to obtain a second mixture. Perform a second drying and a second sintering on the obtained second mixture to obtain a matrix. Here, the matrix has a composition represented by Formula I, Na 1-x [Ni y Mn z M u Ti v O2 Formula I In the formula, -0.4 ≦ x ≦ 0.4, 0.2 ≦ y ≦ 0.6, 0.1 ≦ z ≦ 0.5, 0.1 ≦ u ≦ 0.5, 0 ≦ v ≦ 0.02, and y + z + u + v = 1, and M is selected from at least one of Fe, Mg, Al, Cu, Zn, Zr, Nb, Co, Y, V, Sc, Cr, W, La, Mo, Os, Pr, Re, Ru, Sr, Sm, and Ta. (3) Perform a third mixing on the coating layer and the matrix to obtain a third mixture. Heat-treat the obtained third mixture to obtain a composite cathode material. Here, the first sintering is performed in a non-oxidizing gas.

[0009] A third aspect of the present invention provides a sodium ion cathode material manufactured by the method according to the second aspect.

[0010] The fourth aspect of the present invention provides for the use of the sodium ion cathode material according to the first aspect or the third aspect in a sodium ion battery.

[0011] The fifth aspect of the present invention provides a sodium ion battery including a positive electrode sheet manufactured from the sodium ion cathode material according to the first aspect or the third aspect.

[0012] The sixth aspect of the present invention provides a sodium ion battery pack including the sodium ion battery according to the fifth aspect.

[0013] The seventh aspect of the present invention provides an apparatus including the sodium ion battery pack according to the sixth aspect.

Advantages of the Invention

[0014] By the above technical solution, the sodium ion cathode material, its manufacturing method, use, sodium ion battery, sodium ion battery pack, and apparatus according to the present invention have the following beneficial effects.

[0015] (1) In the sodium ion cathode material according to the present invention, the coating of Na 2-β Ti 6-α M′ α O 13 effectively improves the ionic and electronic conductivities and surface activity of the coating layer. At the same time, by coating the coating layer on a specific matrix, the structural stability and chemical stability of the composite cathode material can be significantly improved. (2) In the sodium ion cathode material according to the present invention, the coating layer is a pure phase of a coating containing specific doping elements. While ensuring a high ionic conductivity of the coating layer phase, the electronic conductivity of the coating layer is improved by element doping, and the inhibitory effect on the matrix electrons and ion channels due to the introduction of the coating layer can be avoided. Preferably, in the sodium ion cathode material, the Ti element in the matrix is distributed in a gradient manner. Furthermore, the Ti element in the matrix is contained in the Na2Ti6O in the coating layer 13It becomes easier to form a Na-Ti-O chemical bond with the phase, and after realizing a tight coating of the coating layer, the interfacial impedance is further reduced. (3) The method for manufacturing the composite positive electrode material according to the present invention heat-treats the coating layer in a non-oxidizing gas to more tightly bond the coating layer and the matrix, thereby improving the electrochemical performance of a sodium-ion battery manufactured with the sodium-ion positive electrode material, and the method simplifies the process and is convenient for industrial production. (4) The sodium-ion positive electrode material according to the present invention is used in a sodium-ion battery and can effectively improve the cycle life, rate, and safety performance of the battery.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

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Figure 5

Modes for Carrying Out the Invention

[0017] Neither the endpoints of the ranges disclosed in this specification nor any arbitrary values are limited to their exact ranges or values, and these ranges or values should be understood to include values close to these ranges or values. In the case of numerical ranges, between the endpoint values of each range, between the endpoint values and the point values of each range, and between the individual point values, one or more new numerical ranges can be obtained by combining them with each other, and these numerical ranges shall be regarded as specifically disclosed in this specification.

[0018] In the present invention, unless otherwise specified in special circumstances, the terms "first", "second", and "third" do not indicate priority, do not play a limiting role for each material or step, but are merely used to distinguish that they are not the same material or step. For example, "first" and "second" in "the first sodium source" and "the second sodium source" are merely used to distinguish that they are not the same sodium source, and "first", "second", and "third" in "the first mixing", "the second mixing", and "the third mixing" are merely used to distinguish that they are not the same mixing.

[0019] The first aspect of the present invention provides a sodium ion cathode material, which includes a matrix and a coating layer coated on the matrix. The matrix has a composition represented by Formula I. Na 1-x [Ni y Mn z M u Ti v O2 Formula I In the formula, -0.4 ≦ x ≦ 0.4, 0.2 ≦ y ≦ 0.6, 0.1 ≦ z ≦ 0.5, 0.1 ≦ u ≦ 0.5, 0 ≦ v ≦ 0.02, y + z + u + v = 1, and M is selected from at least one of Fe, Mg, Al, Cu, Zn, Zr, Nb, Co, Y, V, Sc, Cr, W, La, Mo, Os, Pr, Re, Ru, Sr, Sm, and Ta. The coating layer has a composition represented by Formula II. Na 2-β Ti 6-α M′ α O 13 Formula II In the formula, 0 ≦ α < 0.6, -2 ≦ β < 1, and M′ is selected from at least one of Li, Mg, Fe, Al, Ga, In, Ge, Y, Sc, and Zr.

[0020] In the present invention, the sodium ion cathode material has a coating layer Na 2-β Ti 6-α M′ α O 13including the same Na2Ti6O as the central average part of the matrix 13 phase, and the Na2Ti6O of the coating layer 13 phase has the same crystal structure as the Na2Ti6O in the matrix, and the Na-Ti-O chemical bonds existing in both are organically bonded to achieve the purpose of a tight coating. Finally, the matrix and the Na 13 coated on the matrix can 2-β Ti 6-α M′ α O 13 The sodium ion cathode material including the coating layer has high ion and electron conductivity, excellent structural stability and chemical stability.

[0021] In a specific embodiment of the present invention, in formula I, -0.2 ≦ x ≦ 0.4, 0.2 ≦ y ≦ 0.5, 0.2 ≦ z ≦ 0.5, 0.2 ≦ u ≦ 0.5, 0.01 ≦ v ≦ 0.02, y + z + u + v = 1, and M is selected from at least one of Fe, Cu, Nb, Co, V and Cr.

[0022] In a preferred embodiment of the present invention, in formula I, 0 ≦ x ≦ 0.35, 0.3 ≦ y ≦ 0.4, 0.2 ≦ z ≦ 0.4, 0.2 ≦ u ≦ 0.4, 0.01 < v ≦ 0.02, y + z + u + v = 1, and M is selected from at least one of Fe, Cu, Nb and V.

[0023] In a specific embodiment of the present invention, in formula II, 0 < α < 0.5, -2 ≦ β < 1, and M′ is selected from at least one of Mg, Fe, Al, Y and Zr.

[0024] In a preferred embodiment of the present invention, in formula II, 0.01 ≦ α < 0.3, -2 ≦ β < 0.5, and M′ is selected from at least one of Fe, Mg and Al.

[0025] In the present invention, in formula II, the numerical value of β depends on the change of each ionic valence number in formula II to ensure the charge balance of the coating layer material.

[0026] According to the present invention, along the direction from the center of the matrix to its surface, the Ti element is distributed in a gradient, preferably increasing in a gradient.

[0027] In the present invention, the Ti element in the matrix is distributed in a gradient. Preferably, along the direction from the center of the matrix to its surface, the Ti element is distributed in a gradient, that is, by controlling the content of the Ti element on the matrix surface to be high, the Ti element in the matrix is included in the Na2Ti6O in the coating layer 13 It is easy to form a Na-Ti-O chemical bond with the phase, and after realizing a tight coating of the coating layer, the interfacial impedance is further reduced.

[0028] Furthermore, along the direction from the center of the matrix to its surface, the increasing rate of the Ti element is 0.001 - 0.3 mol% / μm, preferably 0.001 - 0.2 mol% / μm, and more preferably 0.001 - 0.1 mol% / μm.

[0029] In some embodiments of the present invention, preferably, the weight ratio of the matrix to the coating layer is 100:0.01 - 5, for example, 100:0.01, 100:0.05, 100:0.1, 100:0.5, 100:1, 100:3, 100:5, and any value within the range composed of any two numerical values, preferably 100:0.05 - 3. At a preferred weight ratio, the coating layer can form a uniform coating of the matrix and has a relatively high coating density, and can effectively suppress the side reaction between the matrix and the electrolyte. At the same time, the thickness of the coating layer is not too thick to affect the performance of the capacity and rate of the positive electrode material.

[0030] In some embodiments of the present invention, preferably, the thickness of the coating layer is 10 - 200 nm, preferably 10 - 100 nm, and more preferably 50 - 100 nm.

[0031] In some embodiments of the present invention, preferably, the average particle size D50 of the sodium ion cathode material is 2-30 μm, preferably 4-12 μm.

[0032] In the present invention, unless otherwise specified, the parameter of the average particle size D50 is measured by a laser particle size analyzer, the parameter of the average particle size D50 is measured by a laser particle size analyzer, and the parameter of the thickness is measured by a transmission electron microscope.

[0033] In some embodiments of the present invention, preferably, the ionic conductivity of the sodium ion cathode material is 10 -4 ~10 -3 S / cm, preferably 5×10 -4 ~10 -3 S / cm.

[0034] In some embodiments of the present invention, preferably, the electronic conductivity of the sodium ion cathode material is 10 -7 ~10 -6 S / cm, preferably 5×10 -7 ~10 -6 S / cm.

[0035] In the present invention, unless otherwise specified, the ionic conductivity of the sodium ion cathode material is measured by an electrochemical workstation, and the electronic conductivity of the sodium ion cathode material is measured by a powder resistance tester.

[0036] The coating layer of the sodium ion cathode material in the present invention is heat-treated in a non-oxidizing gas to more tightly bond the coating layer and the matrix, thereby improving the electrochemical performance of the sodium ion battery manufactured with the sodium ion cathode material.

[0037] The second aspect of the present invention provides a method for manufacturing a sodium ion cathode material, and the method includes the following steps.

[0038] (1) Perform a first mixing on the first sodium source, a selectable M' source, a titanium source, and a solvent to obtain a first slurry. Sequentially perform a first drying and a first sintering on the first slurry to obtain a first sintered product. Sequentially perform crushing and drying on the obtained first sintered product to obtain a coating layer. Here, the coating layer has a composition represented by Formula II, Na 2-β Ti 6-α M' α O 13 Formula II In the formula, 0 ≦ α < 0.6, -2 ≦ β < 1, and M' is selected from at least one of Li, Mg, Fe, Al, Ga, In, Ge, Y, Sc, and Zr. (2) Perform a second mixing on the second sodium source, a nickel source, a manganese source, an M source, and a selectable titanium source to obtain a second mixture. Sequentially perform a second drying and a second sintering on the obtained second mixture to obtain a matrix. Here, the matrix has a composition represented by Formula I, Na 1-x [Ni y Mn z M u Ti v O2 Formula I In the formula, -0.4 ≦ x ≦ 0.4, 0.2 ≦ y ≦ 0.6, 0.1 ≦ z ≦ 0.5, 0.1 ≦ u ≦ 0.5, 0 ≦ v ≦ 0.02, and y + z + u + v = 1, and M is selected from at least one of Fe, Mg, Al, Cu, Zn, Zr, Nb, Co, Y, V, Sc, Cr, W, La, Mo, Os, Pr, Re, Ru, Sr, Sm, and Ta. (3) Perform a third mixing on the coating layer and the matrix to obtain a third mixture. Heat-treat the obtained third mixture to obtain the sodium ion positive electrode material. Here, the first sintering is performed in a non-oxidizing gas.

[0039] In the present invention, by adopting the manufacturing method described in the second aspect of the present invention, a coating layer having a specific composition and a matrix having a specific composition are mixed and then heat-treated to obtain the sodium ion positive electrode material described in the first aspect of the present invention. In the sodium ion positive electrode material, a coating layer Na 2-β Ti 6-α M′ α O 13 is included, has the same Na2Ti6O 13 phase as the central average part of the matrix, and the Na2Ti6O 13 phase of the coating layer has the same crystal structure as the Na2Ti6O 13 phase in the matrix. The Na-Ti-O chemical bonds existing in both of them are organically bonded, and the purpose of achieving a tight coating can be achieved. Finally, the matrix and the Na 2-β Ti 6-α M′ α O 13 coating layer-containing sodium ion positive electrode material has high ion and electron conductivity, excellent structural stability and chemical stability.

[0040] According to the present invention, the content of surface residual alkali in the matrix is ≦ 2 wt%.

[0041] In the present invention, since the surface residual alkali is an inert layer, if the content of the residual alkali is too high, a thick inert layer will be formed between the coating layer and the matrix, affecting the bonding of the chemical bond between the matrix and the coating layer. In order to realize the tight bonding between the coating layer and the matrix, it is necessary to control the content of the surface residual alkali in the matrix to be less than 2 wt%, and preferably, control the content of the surface residual alkali in the matrix to be 0.1 - 1 wt%.

[0042] Furthermore, in the present invention, by performing the first sintering in a non-oxidizing gas to manufacture the coating layer, Ti 2-β Ti 6-α M′ α O 13 in 4+Since the content of can be reduced and a certain amount of oxygen vacancies can be increased, the coating layer material has a certain activity, and in the process of coating the coating layer on the matrix, the tendency to bind to the oxygen suspension bonds on the matrix surface becomes stronger, further improving the tight bonding degree between the coating layer and the matrix, and improving the structural stability and cycle performance of the sodium ion positive electrode material.

[0043] In the present invention, unless otherwise specified, the supply amounts of all materials are all used for the production of the product, that is, the supply amounts of the first sodium source, M'source, and titanium source satisfy the composition of formula II, and the supply amounts of the second sodium source, nickel source, manganese source, and M source satisfy the composition of formula I.

[0044] In the present invention, the non-oxidizing gas refers to a gas that does not contain oxygen. Preferably, the non-oxidizing gas includes, but is not limited to, nitrogen, helium, argon, and neon.

[0045] In the present invention, the method of the first mixing in step (1) has a wide selection range, and the first sodium source, M'source, titanium source, and solvent may be uniformly mixed.

[0046] In the present invention, in step (1), the types of the first sodium source, M'source, and titanium source have a wide selection range, and the first sodium source, M'source, and titanium source may each contain Na, M', and Ti. Here, M' is selected from at least one of Li, Mg, Fe, Al, Ga, In, Ge, Y, Sc, and Zr. Preferably, M' is selected from at least one of Mg, Fe, Al, Y, and Zr. Preferably, the first sodium source, M'source, and titanium source are each selected from at least one of oxides, hydroxides, nitrates, carbonates, and organic compounds containing Na, M', and Ti.

[0047] In some embodiments of the present invention, preferably, in step (1), the supply amounts of the first sodium source, M'source, and titanium source satisfy n(Na):n(Ti):n(M')=(2-β):(6-α):α, where 0≦α<0.6 and -2≦β<1.

[0048] In some preferred embodiments of the present invention, preferably, in step (1), 0 ≦ α < 0.6 and -2 ≦ β < 1, where 0 < α < 0.5 and -2 ≦ β < 1. More preferably, 0.01 ≦ α < 0.3 and -2 ≦ β < 0.5.

[0049] In the present invention, the first drying means removing the solvent in the first slurry. Preferably, the apparatus for the first drying includes, but is not limited to, a spray dryer, a forced-air oven, a vacuum oven, a freeze dryer, etc. In the present invention, the conditions for the first drying are not particularly limited as long as the solvent in the first slurry is removed.

[0050] In some embodiments of the present invention, preferably, the solid content of the first slurry is 30 - 55 wt%. In the present invention, when the solid content of the first slurry is controlled to satisfy the above range, each material in the slurry has good dispersibility, and the presence of excessive solvent does not adversely affect the matrix structure. For example, excessive solvent does not cause sodium ions in the matrix to escape from the matrix.

[0051] In the present invention, the type of the solvent has a wide selection range, and the solvent may dissolve the first sodium source, the M' source, and the titanium source. Preferably, the solvent includes, but is not limited to, common solvents such as water, ethanol, ethylene glycol, and glycerol.

[0052] In the present invention, the dosage of the solvent has a wide selection range, and it is sufficient that the solid content in the first slurry satisfies 30 - 55 wt%.

[0053] In some embodiments of the present invention, preferably, in step (1), the conditions for the first sintering are that the temperature is 500 - 1200 °C, preferably 700 - 850 °C, and the time is 4 - 10 h, preferably 6 - 8 h.

[0054] In the present invention, when controlling the conditions of the first sintering to satisfy the above range, it is possible to ensure obtaining a pure-phase coating layer. Therefore, the obtained coating layer has excellent crystallinity and structural stability. When it is used for coating the matrix, a dense and uniform coating layer can be formed on the surface of the matrix, and furthermore, the charge-discharge capacity and cycle performance of the sodium ion positive electrode material can be significantly improved. Specifically, if the sintering temperature is too low or the sintering time is too short, non-uniform phases will appear in the obtained coating layer. If the sintering temperature is too high or the sintering time is too long, the hardness of the obtained coating layer will be too high and it will be difficult to crush.

[0055] In some embodiments of the present invention, preferably, in step (1), the crushing process includes crushing the first sintering product and the solvent at a weight ratio of 100:50 - 100.

[0056] In the present invention, the first sintering product is crushed according to the above method, which has a higher crushing efficiency. At the same time, the obtained coating layer has excellent structural stability and dispersibility.

[0057] In the present invention, the type of the solvent during ball milling is not particularly limited as long as the first sintering product can be uniformly dispersed.

[0058] In the present invention, the crushing device includes, but is not limited to, jaw crushers, roller machines, ball mills, jet mills, mechanical mills, sand mills, colloid mills, etc.

[0059] In some embodiments of the present invention, preferably, due to the crushing, the average particle size D50 of the coating layer is 10 - 200 nm, preferably 10 - 100 nm, and more preferably 50 - 100 nm.

[0060] In some embodiments of the present invention, preferably, the drying process includes a temperature of 60 - 120 °C and a time of 0.5 - 5 h.

[0061] In some embodiments of the present invention, preferably, the dried product is pulverized.

[0062] In the present invention, the method of the second mixing in step (2) has a wide selection range, and the second sodium source, nickel source, manganese source, and M source may be uniformly mixed.

[0063] In the present invention, the types of the second sodium source, nickel source, manganese source, and M source have a wide selection range. The second sodium source, nickel source, manganese source, and M source may each contain Na, Ti, Mn, and M, respectively. Here, M is selected from at least one of Fe, Mg, Al, Cu, Zn, Zr, Nb, Co, Ti, Y, V, Sc, Cr, W, La, Mo, Os, Pr, Re, Ru, Sr, Sm, and Ta. Preferably, M is selected from at least one of Fe, Cu, Nb, Co, V, and Cr. Preferably, in step (2), the second sodium source, nickel source, manganese source, and M source are each independently selected from at least one of oxides, hydroxides, carbonates, nitrates, and organic compounds containing Na, Ni, Mn, and M, respectively.

[0064] In the present invention, the second drying means removing moisture in the second mixture. Here, the drying apparatus includes, but is not limited to, a spray dryer, a forced-air oven, a vacuum oven, a freeze dryer, etc.

[0065] In some embodiments of the present invention, preferably, the supply amounts of the second sodium source, nickel source, manganese source, M source, and optional titanium source satisfy n(Na):n(Ni):n(Mn):n(M):n(Ti)=(1 - x):y:z:u:v, where -0.4 ≦ x ≦ 0.4, 0.2 ≦ y ≦ 0.6, 0.1 ≦ z ≦ 0.5, 0.1 ≦ u ≦ 0.5, 0 ≦ v ≦ 0.02, and y + z + u + v = 1.

[0066] In some preferred embodiments of the present invention, preferably, the supply amounts of the second sodium source, nickel source, manganese source, M source, and optional titanium source satisfy n(Na):n(Ni):n(Mn):n(M):n(Ti) = (1 - x):y:z:u:v, where -0.2 ≦ x ≦ 0.4, 0.2 ≦ y ≦ 0.5, 0.2 ≦ z ≦ 0.5, 0.2 ≦ u ≦ 0.5, 0.01 ≦ v ≦ 0.02, and y + z + u + v = 1. More preferably, 0 ≦ x ≦ 0.35, 0.3 ≦ y ≦ 0.4, 0.2 ≦ z ≦ 0.4, 0.2 ≦ u ≦ 0.4, 0.01 < v ≦ 0.02, and y + z + u + v = 1.

[0067] In some embodiments of the present invention, preferably, the second mixing co-precipitates the nickel source, manganese source, and M source to obtain a precursor Ni y Mn z M u (OH)2, and after performing mixing I on the precursor Ni y Mn z M u (OH)2 and the titanium source, further performing mixing II with the second sodium source to obtain a second mixture.

[0068] In the present invention, the second mixing is performed according to the above steps, that is, first mixing the precursor and the titanium source, then mixing with the second sodium source, and then performing the second sintering. By controlling the time of the second sintering, the Ti element is distributed in a gradient manner in the matrix. In particular, along the direction from the center to the surface of the matrix, the Ti element is distributed in an increasing manner in the matrix.

[0069] In the present invention, the conditions for co-precipitation are not particularly limited, and co-precipitation of the nickel source, manganese source, and M source can be realized according to the conventional conditions in this field.

[0070] In the present invention, the conditions for mixing I and mixing II are not particularly limited, and it is only necessary to sufficiently mix the precursor and the titanium source, and the mixture of the two and the second sodium source.

[0071] In some embodiments of the present invention, preferably, the conditions for the second sintering are that the temperature is 600 - 1200 °C, preferably 750 - 1200 °C, the time is 6 - 10 h, and preferably 8 - 10 h.

[0072] In the present invention, when the conditions for the second sintering are controlled to satisfy the above range, it can be ensured that the obtained matrix has excellent crystallinity and structural stability, and further, the charge and discharge capacity and cycle performance of the sodium ion positive electrode material containing the matrix material are significantly improved. Specifically, if the sintering temperature is too low or the sintering time is too short, the materials in the matrix do not react completely, and a non-uniform phase appears in the matrix. If the sintering temperature is too high or the sintering time is too long, the sodium ions in the matrix volatilize, which further affects the electrochemical performance of the battery containing the obtained sodium ion positive electrode material. In the present invention, the method of the third mixing in step (3) has a wide selection range, and the coating layer and the matrix may be uniformly mixed.

[0073] In some embodiments of the present invention, preferably, in step (3), the heat treatment is performed in a non-oxidizing gas. In the present invention, when the heat treatment is controlled to be performed in a non-oxidizing gas, it is advantageous for the bonding of the oxygen suspension bonds on the surfaces of the coating layer material and the matrix material, thereby bonding the coating layer and the matrix more tightly, and further improving the cycle performance of the sodium ion battery containing the sodium ion positive electrode material.

[0074] In some embodiments of the present invention, preferably, in step (3), the conditions for the heat treatment are that the temperature is 200 - 600 °C, preferably 400 - 600 °C, the time is 4 - 8 h, and preferably 6 - 8 h.

[0075] In the present invention, when the conditions for the heat treatment are controlled to satisfy the above range, sufficient reaction between the matrix and the coating layer can be ensured, and the two can be tightly bonded, and further, the cycle performance of the sodium ion battery containing the sodium ion positive electrode material is improved.

[0076] In some embodiments of the present invention, preferably, the third mixing is performed by directly mixing the coating layer and the matrix, or mixing the coating layer and a solvent and performing ball milling to obtain a second slurry, and performing the third mixing on the second slurry and the matrix.

[0077] In the present invention, the conditions of ball milling are not particularly limited, and the coating layer and the solvent may be sufficiently mixed.

[0078] In the present invention, the dosage of the solvent during ball milling is not particularly limited, as long as the solid content of the second slurry obtained after ball milling is 30-55 wt%. In the present invention, the type of the solvent during ball milling is not particularly limited, as long as uniform dispersion of the coating layer is achieved.

[0079] In some embodiments of the present invention, preferably, in step (3), the weight ratio of the coating layer to the matrix is 0.01-5:100, for example, 0.01:100, 0.05:100, 0.1:100, 1:100, 3:100, 5:100, and any value within the range consisting of any two numerical values, preferably 0.05-3:100. At a preferred weight ratio, the coating layer can form a uniform coating of the matrix and has a relatively high coating density, and can effectively suppress the side reaction between the matrix and the electrolyte. At the same time, if the thickness of the coating layer is too thick, it will not affect the performance of the material's capacity and rate performance. If the weight ratio is less than 0.01:100, the coating of the coating layer on the matrix will be incomplete, and the exposed uncoated part still has a side reaction with the electrolyte, resulting in a rapid deterioration of the cycle performance. If the weight ratio is greater than 5:100, the thickness of the coating layer on the matrix surface is too high, increasing the transport path of lithium ions and affecting the performance of the capacity and rate.

[0080] The third aspect of the present invention provides a sodium ion positive electrode material manufactured by the manufacturing method according to the second aspect.

[0081] A fourth aspect of the present invention provides for the use of the sodium ion cathode material according to the first aspect or the third aspect in a sodium ion battery.

[0082] A fifth aspect of the present invention provides a sodium ion battery including a cathode sheet manufactured from the sodium ion cathode material according to the first aspect or the third aspect.

[0083] In some embodiments of the present invention, preferably, the sodium ion battery has a retention rate of ≧75%, preferably 90 - 100% at 25°C after 80 cycles.

[0084] In some embodiments of the present invention, preferably, when in a charged state of 4.2V, the DSC heat release temperature of the cathode sheet is ≧280°C, preferably 290 - 350°C.

[0085] A sixth aspect of the present invention provides a sodium ion battery pack including the sodium ion battery according to the fifth aspect.

[0086] A seventh aspect of the present invention provides an apparatus including the sodium ion battery pack according to the sixth aspect.

[0087] Hereinafter, the present invention will be described in detail by way of examples. The ionic conductivity was measured with an electrochemical workstation. The Ti element concentration gradient was measured with a scanning electron microscope EDS. The electronic conductivity was measured by the four-probe method using a powder resistance tester. The content of residual alkali was measured by the national standard method using a potentiometric titration apparatus. The phases of the cathode material and the coating layer were measured by the national standard method using an XRD diffractometer. All raw materials used in the examples and comparative examples are commercially available products.

[0088] Production Example - Precursor Ni y Mn z M u(OH)2 Production Nickel sulfate, manganese sulfate, and ferrous sulfate were mixed so that the supply amounts satisfied n(Ni):n(Mn):n(Fe)=0.33:0.33:0.33, and co-precipitated with aqueous ammonia and sodium hydroxide at 55 °C for 46 h, washed, and dried to obtain the precursor Ni 0.33 Fe 0.33 Mn 0.33 (OH)2.

[0089] Example 1 (1) Na2CO3, TiO2, Fe2O3, and water were mixed to obtain a slurry with a solid content of 50 wt%. Here, the supply amounts of Na2CO3, TiO2, and Fe2O3 satisfied n(Na):n(Ti):n(Fe)=2:5.9:0.1. The obtained slurry was processed in a spray dryer to obtain a dried powder. The drying temperature was 110 °C, and the drying time was 0.5 h. Under a nitrogen atmosphere, the powder was sintered at 800 °C for 6 h to obtain a first sintered material. Next, after mixing the first sintered material and pure water (weight ratio 100:100), it was sand-milled in a sand mill for 4 h to obtain a slurry with an average particle size D 50 of 50 nm. After drying the slurry in a vacuum oven at 80 °C for 2 h, a powder was obtained. The powder was pulverized with a jet mill to obtain a coating layer C1. Here, the chemical composition of the coating layer C1 is Na2Ti 5.9 Fe 0.1 O 13 , and the average particle diameter D 50 is 100 nm. (2) The supply amounts of Na2CO3, Ni 0.33 Fe 0.33 Mn 0.33 (OH)2, and TiO2 satisfied n(Na):[n(Ni)+n(Mn)+n(M)]:n(Ti)=1.03:0.99:0.01. The mixture of Ni 0.33 Fe 0.33 Mn 0.33 (OH)2 and TiO2 was first dry ball-milled for 4 h to mix, and then Na2CO3 and Ni 0.33 Fe 0.33 Mn 0.33The mixture of (OH)2 and TiO2 was dry ball milled for 4 h to mix, and the obtained second mixture was sintered in a muffle furnace at 950 °C for 8 h to obtain matrix B1. Here, the chemical composition of matrix B1 is Na 1.03 Ni 0.33 Fe 0.33 Mn 0.33 Ti 0.01 O2. (3) The coating layer C1 and matrix B1 were mixed in a high mixer at a weight ratio of 1:100 at a rotational speed of 1000 rpm for 20 min to obtain a third mixture. The mixture of the third mixture was heat treated in a muffle furnace under a nitrogen atmosphere at 300 °C for 4 h to obtain a sodium ion positive electrode material S1. For the sodium ion positive electrode material S1, the sodium ion positive electrode material S1 is Na2Ti 5.9 Fe 0.1 O 13 coated Na 1.03 Ni 0.33 Fe 0.33 Mn 0.33 Ti 0.01 O2.

[0090] Example 2 A sodium ion positive electrode material was manufactured according to the method of Example 1. Specifically, it is as follows. (1) Similar to Example 1, a coating layer C2 was manufactured. Here, the chemical composition of the coating layer C2 is Na2Ti 5.9 Fe 0.1 O 13 and the average particle size D 50 is 100 nm. (2) The supply amounts of Na2CO3, Ni 0.33 Fe 0.33 Mn 0.33 (OH)2 satisfy n(Na):[n(Ni)+n(Mn)+n(M)] = 1.03:1, and were dry ball milled and mixed in a mixing tank at a rotational speed of 850 rpm for 4 h. The obtained second mixture was sintered in a muffle furnace at 950 °C for 8 h to obtain matrix B2. Here, the chemical composition of matrix B2 is Na 1.03 Ni 1 / 3 Fe 1 / 3 Mn 1 / 3It is O2. (3) The above coating layer C2 and matrix B2 were mixed in a high mixer at a weight ratio of 1:100 at a rotation speed of 1000 rpm for 20 min to obtain a third mixture. The above mixture was heat-treated in a muffle furnace under a nitrogen atmosphere at 300 °C for 4 h to obtain a sodium ion cathode material S2. Here, the sodium ion cathode material S2 is Na2Ti 5.9 Fe 0.1 O 13 coated with Na 1.03 Ni 1 / 3 Fe 1 / 3 Mn 1 / 3 It is O2.

[0091] Example 3 (1) Na2CO3, TiO2 and water were mixed to obtain a slurry with a solid content of 50 wt%. Here, the supply amounts of Na2CO3 and TiO2 satisfied n(Na):n(Ti)=2:6. The obtained slurry was treated in a spray dryer to obtain a dried powder. The drying temperature was 110 °C and the drying time was 0.5 h. Under a nitrogen atmosphere, the powder was sintered at 800 °C for 6 h to obtain a first sintered material. Next, after mixing the first sintered material and pure water (weight ratio 100:100), it was sand-milled in a sand mill for 4 h to obtain a slurry with an average particle size D 50 of 50 nm. After drying the slurry in a vacuum oven at 80 °C for 2 h, a powder was obtained. The powder was pulverized by a jet mill to obtain a coating layer C3. Here, the chemical composition of the coating layer C3 is Na2Ti6O 13 and the average particle size D50 is 100 nm. (2) In the same manner as in step (2) of Example 1, a matrix B3 was produced. Here, the chemical composition of the matrix B3 is Na 1.03 Ni 0.33 Fe 0.33 Mn 0.33 Ti 0.01 It is O2. (3) The above coating layer C3 and matrix B3 were mixed in a high mixer at a weight ratio of 1:100 at a rotation speed of 1000 rpm for 20 min to obtain a third mixture. The above mixture was heat-treated in a muffle furnace under a nitrogen atmosphere at 300 °C for 4 h to obtain a sodium ion cathode material S3. The sodium ion cathode material S3 is Na2Ti6O13 Na coated with 1.03 Ni 0.33 Fe 0.33 Mn 0.33 Ti 0.01 is O2.

[0092] Example 4 Manufacture a sodium ion positive electrode material according to the method of Example 1. Specifically, it is as follows. (1) Similar to Example 1, produce the coating layer C4. (2) The supply amounts of Na2CO3, Ni 0.33 Fe 0.33 Mn 0.33 (OH)2, and TiO2 satisfy n(Na):[n(Ni)+n(Mn)+n(M)]:n(Ti)=1.03:0.99:0.01. First, mix the mixture of Ni 0.33 Fe 0.33 Mn 0.33 (OH)2 and TiO2 in a dry ball mill at 850 rpm for 4 h, and then mix the mixture of Na2CO3 and Ni 0.33 Fe 0.33 Mn 0.33 (OH)2 and TiO2 in a dry ball mill at 850 rpm for 4 h. Sinter the obtained second mixture in a muffle furnace at 950 °C for 10 h to obtain matrix B4. Here, the chemical composition of matrix B1 is Na 1.03 Ni 0.33 Fe 0.33 Mn 0.33 Ti 0.01 is O2. (3) Mix the above coating layer C4 and matrix B4 in a high mixer at a weight ratio of 1:100 at a rotation speed of 1000 rpm for 20 min to obtain a third mixture. Heat-treat the above mixture in a muffle furnace under a nitrogen atmosphere at 300 °C for 4 h to obtain a sodium ion positive electrode material S4. Here, the sodium ion positive electrode material S4 is Na coated with Na2Ti6O 13 1.03 Ni 0.33 Fe 0.33 Mn 0.33 Ti 0.01 is O2.

[0093] Example 5 Manufacture a sodium-ion cathode material according to the method of Example 1. Specifically, it is as follows. (1) Manufacture the coating layer C5 in the same manner as in Example 1. (2) Manufacture the matrix B5 in the same manner as in Example 1. (3) Mix the above coating layer C5 and matrix B5 in a weight ratio of 1:100 in a high mixer at a rotation speed of 1000 rpm for 20 min to obtain a third mixture. Heat-treat the third mixture in a muffle furnace in an oxygen atmosphere at 300 °C for 4 h to obtain a sodium-ion cathode material S5. The sodium-ion cathode material S5 is Na2Ti 5.9 Fe 0.1 O 13 coated with Na 1.03 Ni 0.33 Fe 0.33 Mn 0.33 Ti 0.01 O2.

[0094] Example 6 Manufacture a sodium-ion cathode material according to the method of Example 1. Specifically, it is as follows. (1) Manufacture the coating layer C6 in the same manner as in step (1) of Example 3. Here, the chemical composition of the coating layer C6 is Na2Ti6O 13 and the average particle size D50 is 100 nm. (2) Manufacture the matrix B6 in the same manner as in step (2) of Example 2, where the chemical composition of the matrix B6 is Na 1.03 Ni 1 / 3 Fe 1 / 3 Mn 1 / 3 O2. (3) After mixing the coating layer C6 and the matrix B6 in the same manner as in Example 1, heat-treat to obtain a sodium-ion cathode material S6. Here, the sodium-ion cathode material S6 is Na2Ti6O 13 coated with Na 1.03 Ni 1 / 3 Fe 1 / 3 Mn 1 / 3 O2.

[0095] Example 7 Manufacture a sodium ion cathode material according to the method of Example 1. Specifically, it is as follows. (1) Instead of Fe2O3, use Al2O3 to manufacture the coating layer C7. Here, the chemical composition of the coating layer C7 is Na2Ti 5.9 Al 0.1 O 13 and the average particle size D50 is 100 nm. (2) Similar to Example 1, manufacture the matrix B7. (3) Similar to Example 1, after mixing the coating layer C7 and the matrix B7, perform heat treatment to obtain the sodium ion cathode material S7. Here, the sodium ion cathode material S7 is coated with Na2Ti 5.9 Al 0.1 O 13 and is Na 1.03 Ni 0.33 Fe 0.33 Mn 0.33 Ti 0.01 O2.

[0096] Example 8 Manufacture a sodium ion cathode material according to the method of Example 1. Specifically, it is as follows. (1) Mix Na2CO3, TiO2, MgO and water to obtain a slurry with a solid content of 50 wt%. Here, the supply amounts of Na2CO3, TiO2, and MgO satisfy n(Na):n(Ti):n(Mg)=2.2:5.9:0.1. Treat the obtained slurry in a spray dryer to obtain a dried powder. The drying temperature is 110 °C, the drying time is 0.5 h. Under a nitrogen atmosphere, sinter the powder at 800 °C for 6 h to obtain the first sintered material. Next, after mixing the first sintered material and pure water (weight ratio 100:100), perform sand milling in a sand mill for 4 h to obtain a slurry with an average particle size D50 of 50 nm. After drying the slurry in a vacuum oven at 80 °C for 2 h, obtain a powder. Grind the powder with a jet mill to obtain the coating layer C8. Here, the chemical composition of the coating layer C8 is Na 2.2 Ti 5.9 Mg 0.1 O 13 and the average particle size D50 is 100 nm. (2) Similar to Example 1, produce Matrix B8. (3) Different from Example 1, the weight ratio of the coating layer C8 to Matrix B8 is 2:100 to obtain the sodium ion positive electrode material S8, where the sodium ion positive electrode material S8 is Na2Ti 5.9 Fe 0.1 O 13 -coated Na 1.03 Ni 0.33 Fe 0.33 Mn 0.33 Ti 0.01 O2.

[0097] Example 9 Produce the sodium ion positive electrode material according to the method of Example 1. Specifically, it is as follows. (1) The same as Example 1. (2) The same as Example 1. (3) Different from Example 1, the weight ratio of the coating layer C1 to Matrix B1 is 0.02:100 to produce the sodium ion positive electrode material S9, where the sodium ion positive electrode material S9 is Na2Ti 5.9 Fe 0.1 O 13 -coated Na 1.03 Ni 0.33 Fe 0.33 Mn 0.33 Ti 0.01 O2.

[0098] Example 10 Produce the sodium ion positive electrode material according to the method of Example 1. Specifically, it is as follows. (1) The same as Example 1. (2) The same as Example 1. (3) Different from Example 1, the weight ratio of the coating layer C1 to Matrix B1 is 6:100 to obtain the sodium ion positive electrode material S10, where the sodium ion positive electrode material S10 is Na2Ti 5.9 Fe 0.1 O 13 -coated Na 1.03 Ni 0.33 Fe 0.33 Mn 0.33Ti 0.01 It is O2.

[0099] Comparative Example 1 Na2CO3, Ni 0.33 Fe 0.33 Mn 0.33 (OH)2, the supply amount of TiO2 satisfies n(Na):[n(Ni)+n(Mn)+n(M)]:n(Ti)=1.03:0.99:0.01, and it is dry ball milled at 850 rpm for 4 h in a mixing tank for mixing. The obtained mixed material is sintered in a muffle furnace at 950 °C for 8 h to obtain a positive electrode material D1. Here, the chemical composition of D1 is Na 1.03 Ni 0.33 Fe 0.33 Mn 0.33 Ti 0.01 It is O2.

[0100] Comparative Example 2 A sodium ion positive electrode material is produced according to the method of Example 1. The differences are as follows. (1) In an oxygen atmosphere, the dried powder is sintered to obtain a coating layer DC2. Here, the chemical composition of the coating layer DC2 is Na 1.8 Ti 5.9 Fe 0.1 O 12.9 and the average particle size is 100 nm. (2) It is the same as in Example 1. (3) Similar to Example 1, a sodium ion positive electrode material DS2 is produced.

[0101] Comparative Example 3 A sodium ion positive electrode material is produced according to the method of Example 1, and the differences are as follows. (1) The supply amounts of Na2CO3, TiO2, and Fe2O3 satisfy n(Na):n(Ti):n(Fe)=2:2.9:0.1, and in an oxygen atmosphere, the dried powder is sintered to obtain a coating layer DC3. Here, the chemical composition of the coating layer DC3 is Na2Ti 2.9 Fe 0.1 O7 and the average particle size is 100 nm. (2) It is the same as in Example 1. (3) Similar to Example 1, sodium ion cathode material DS3 is manufactured.

[0102]

Table 1-1

[0103]

Table 1-2

[0104]

Table 1-3

[0105]

Table 1-4

[0106]

Table 1-5

[0107] The particle size, ionic conductivity, electronic conductivity, and volume resistance of the sodium ion cathode materials produced in the examples and comparative examples are measured, and the results are shown in Table 2.

[0108]

Table 2

[0109] Test Example The initial charge-discharge performance and cycle performance tests are performed on the cathode materials produced in the examples and comparative examples.

[0110] The button battery is manufactured according to the following steps, 95 g of the positive electrode material, 2.5 g of acetylene black, and 2.5 g of polyvinylidene fluoride (PVDF) were mixed, coated on an aluminum foil, dried, and press-molded at a pressure of 100 MPa to obtain a positive electrode sheet with a diameter of 12 mm and a thickness of 120 μm. Next, the positive electrode sheet was placed in a vacuum drying oven and dried at 120 °C for 12 h. As the negative electrode, a Na metal sheet with a diameter of 17 mm and a thickness of 1 mm was used. As the separator, a polyethylene porous film with a thickness of 25 μm was used. As the electrolyte, an equal volume mixture of ethylene carbonate (EC) and diethyl carbonate (DEC) with 1 mol / L of NaPF6 as the electrolyte was used. The positive electrode sheet, separator, negative electrode sheet, and electrolyte were assembled into a 2025-type button battery in an Ar gas glove box where both the water content and oxygen content were less than 5 ppm.

[0111] Test conditions: The assembled 2025-type button battery was allowed to stand for 12 h, and the initial charge-discharge capacity parameters were measured in a button battery test cabinet under the conditions of a temperature of 25 °C and 0.1C @ 2.0 - 4.0 V. Next, charge-discharge was performed at rates of 0.1C and 1C to test the rate performance parameters, and charge-discharge was performed 80 cycles at a rate of 1C to test the cycle performance. The button battery was recharged to 4.2 V after being charged and discharged twice at 0.1C. After disassembling the battery, the positive electrode sheet was put into a differential thermal-thermogravimetric analyzer for DSC testing. The results are shown in Table 3.

[0112]

Table 3

[0113] Figure 1 is a cross-sectional EDS line scan diagram of the sodium ion positive electrode material S1 manufactured in Example 1. As can be seen from Figure 1, the Ti element is distributed in a gradient manner in the matrix of the positive electrode material and the Fe element is doped in the coating layer.

[0114] Figure 2 is an XRD diffraction pattern of the coating layer C1 sample manufactured in Example 1. The coating layer C1 is Na2Ti6O 13It can be seen that it is a pure phase of the structure.

[0115] Figure 3 is the XRD diffraction pattern of the positive electrode material manufactured in Comparative Example 1, and it can be seen that the positive electrode material is a pure phase of the NaFeO2 structure.

[0116] Figure 4 is the XRD diffraction pattern of the positive electrode material manufactured in Example 10. In addition to the main phase of the NaFeO2 structure in the positive electrode material, there are diffraction peaks of the Na2Ti6O 13 structure, and it can be seen that there is a coating layer of the Na2Ti6O 13 structure on the surface of the positive electrode material.

[0117] Figure 5 is the DSC spectrum diagram of the positive electrode sheet manufactured with the sodium ion positive electrode materials of Example 1 and Comparative Example 1 when in the 4.2V charged state. As can be seen from Figure 2, the thermal stability of the positive electrode sheet manufactured with the sodium ion positive electrode material of Example 1 with a nano-coating layer constructed on the surface is significantly better than that of the positive electrode sheet manufactured with the sodium ion positive electrode material of Comparative Example 1 without a coating layer, indicating that the safety performance of the sodium ion positive electrode material according to Example 1 is superior to that of the sodium ion positive electrode material of Comparative Example 1.

[0118] As can be seen from the results in Table 3, compared with Comparative Examples 1-3, the sodium ion batteries containing the positive electrode sheets manufactured with the sodium ion positive electrode materials of Examples 1-10 have higher charge-discharge capacity and cycle performance, and the positive electrode sheets have higher thermal runaway temperatures, which means that when the environmental temperature is higher, thermal runaway of the positive electrode material occurs and the battery has significant battery safety.

[0119] Furthermore, the coating layer of the sodium ion positive electrode material of Example 1 contains doping elements and the Ti element in the matrix is distributed in a gradient manner. When the sodium ion positive electrode material is used in a sodium ion battery, the charge-discharge capacity, cycle performance and heat dissipation temperature are further improved.

[0120] As described above in detail, the preferred embodiments of the present invention are not limited thereto. Within the scope of the technical idea of the present invention, many simple modifications are possible to the technical solution of the present invention, including that each technical feature is combined in other appropriate ways. These simple modifications and combinations are similarly regarded as those disclosed in the present invention and all belong to the protection scope of the present invention.

[0121] This application claims the priority of a Chinese patent application with an application number of 202310183846.2, filed with the Chinese Patent Office on February 28, 2023, and all of its contents are incorporated herein by reference.

Claims

1. A sodium ion positive electrode material, wherein the positive electrode material includes a matrix and a coating layer coated on the matrix, the matrix has a composition represented by Formula I, Na １－ｘ [Ni ｙ Mn ｚ M ｕ Ti ｖ O ２ Formula I wherein, -0.4 ≤ x ≤ 0.4, 0.2 ≤ y ≤ 0.6, 0.1 ≤ z ≤ 0.5, 0.1 ≤ u ≤ 0.5, 0 ≤ v ≤ 0.02, y + z + u + v = 1, and M is Fe, the coating layer has a composition represented by Formula II, Na ２－β Ti ６－α M′ α O １３ Formula II wherein, 0 ≤ α < 0.6, -2 ≤ β < 1, and M' is selected from at least one of Mg, Fe, and Al. A sodium ion positive electrode material characterized by this.

2. In Formula I, -0.2 ≤ x ≤ 0.4, 0.2 ≤ y ≤ 0.5, 0.2 ≤ z ≤ 0.5, 0.2 ≤ u ≤ 0.5, 0.01 ≤ v ≤ 0.02, y + z + u + v = 1, and M is Fe. The sodium ion positive electrode material according to Claim 1.

3. Along the direction from the center of the matrix to its surface, Ti element is distributed in a gradient shape. The sodium ion positive electrode material according to Claim 1.

4. The weight ratio of the matrix to the coating layer is 100:0.01 - 5. The sodium ion positive electrode material according to Claim 1.

5. The ionic conductivity of the positive electrode material is 10 －４ to 10 －３ S / cm, and the sodium ion positive electrode material according to claim 1.

6. A method for manufacturing a sodium ion positive electrode material, wherein the manufacturing method includes performing a first mixing on a first sodium source, a selectable M' source, a titanium source, and a solvent to obtain a first slurry, and sequentially performing a first drying and a first sintering on the first slurry to obtain a first sintered product, and sequentially crushing and drying the obtained first sintered product to obtain a coating layer. Step (1), wherein, the coating layer has a composition represented by Formula II, Na ２－β Ti ６－α M′ α O １３ Formula II wherein, 0 ≤ α < 0.6, -2 ≤ β < 1, and M' is selected from at least one of Mg, Fe, and Al. Step (1), and performing a second mixing on a second sodium source, a nickel source, a manganese source, an M source, and a selectable titanium source to obtain a second mixture, and sequentially performing a second drying and a second sintering on the obtained second mixture to obtain a matrix. Step (2), wherein, the matrix has a composition represented by Formula I, Na １－ｘ [Ni ｙ Mn ｚ M ｕ Ti ｖ O ２ Formula I wherein, -0.4 ≤ x ≤ 0.4, 0.2 ≤ y ≤ 0.6, 0.1 ≤ z ≤ 0.5, 0.1 ≤ u ≤ 0.5, 0 ≤ v ≤ 0.02, y + z + u + v = 1, and M is Fe. Step (2), Step (3) of performing a third mixing on the coating layer and the matrix to obtain a third mixture, and heat-treating the obtained third mixture to obtain a sodium ion positive electrode material, wherein here, step (3) where the first sintering is performed in a non-oxidizing gas, is included, and a method for manufacturing a sodium ion positive electrode material is characterized by this. **Claim 7** The manufacturing method according to claim 6, wherein in step (1), the solid content of the first slurry is 30 to 55 wt%. **Claim 8** The second mixing co-precipitates a nickel source, a manganese source, and an M source to obtain a precursor Ni ｙ Mn ｚ M ｕ (OH) ２ and then performs Mixing I on the precursor Ni ｙ Mn ｚ M ｕ (OH) ２ and a titanium source, and then performs Mixing II with a second sodium source to obtain a second mixture. The manufacturing method according to claim 6 includes this step. **Claim 9** The manufacturing method according to any one of claims 6 to 8, wherein the heat treatment is performed in a non-oxidizing gas. **Claim 10** Use of the sodium ion positive electrode material according to any one of claims 1 to 5 in a sodium ion battery. **Claim 11** A sodium ion battery, characterized in that the sodium ion battery includes a positive electrode sheet manufactured with the sodium ion positive electrode material according to any one of claims 1 to 5. **Claim 12** A sodium ion battery pack, characterized by including the sodium ion battery according to claim 11. **Claim 13** An apparatus, characterized by including the sodium ion battery pack according to claim 12.

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