Sodium ion battery positive electrode material and preparation method therefor and application thereof

Abstract

A sodium ion battery positive electrode material and a preparation method therefor and an application thereof. The chemical general formula of the sodium ion battery positive electrode material is NaaNixCuyMnzMbO2+k, wherein 0.6≤a≤1.0, 0.1≤x≤0.4, 0<y≤0.4, 0.3≤z≤0.6, 0<b<0.5, 0<k<0.5, and M comprises metal elements derived from lateritic nickel ore.

Description

A sodium ion battery positive electrode material and its preparation method and application Technical Field

[0001] The embodiments of the present application relate to the field of battery technology, for example, a sodium ion battery positive electrode material and its preparation method and application. Background Art

[0002] Lithium-ion batteries have the characteristics of high energy density and long cycle life and have been widely used in electronic devices. Currently, lithium-ion batteries are expanding into fields such as large-scale energy storage grids and electric vehicles. However, due to the limited and uneven distribution of lithium resources, the problem of high raw material costs has gradually become prominent. Secondary sodium-ion batteries, similar to lithium-ion batteries, have become an important development direction in the field of energy storage due to their low cost, non-toxicity, abundant and evenly distributed sodium resources. Like lithium-ion batteries, the energy storage effect of sodium-ion batteries is also mainly affected by the positive electrode material. Therefore, it is necessary to find a low-cost, high-energy-density and long-cycle sodium-ion battery positive electrode material.

[0003] Sodium-ion battery cathode materials primarily include Prussian blue compounds, layered oxides, and polyanionic compounds. Layered metal oxides have attracted widespread attention due to their high specific capacity, simple preparation process, and low production cost. Unlike lithium-ion batteries, transition metal elements such as Ti, V, Cr, Mn, Fe, Co, Ni, and Cu in sodium-ion battery layered oxide cathodes are electrochemically active. However, current layered oxide sodium battery cathode materials contain large amounts of Ni and Co, which are not only costly but also toxic.

[0004] Based on the above research, it is necessary to provide a sodium ion battery positive electrode material, which can significantly reduce the battery cost without reducing the battery performance.

[0005] Summary of the Invention

[0006] The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

[0007] The embodiments of the present application provide a sodium ion battery cathode material, a preparation method, and an application thereof. The sodium ion battery cathode material introduces low-cost Cu and increases the Mn content to replace the expensive metal Co, thereby significantly reducing the battery cost without sacrificing battery performance. Therefore, the sodium ion battery cathode material described in the present application has the advantages of high energy density, good safety, and low production cost.

[0008] In the first aspect, the present invention provides a sodium ion battery cathode material, the chemical formula of the sodium ion battery cathode material is Naa Ni x Cu y Mn z M b O 2+k , wherein, 0.6≤a≤1.0, 0.1≤x≤0.4, 0<y≤0.4, 0.3≤z≤0.6, 0<b<0.5, 0<k<0.5, and M includes metal elements derived from laterite nickel ore.

[0009] The sodium ion battery positive electrode material described in the present application is a nickel-copper-manganese layered oxide material, with nickel, copper and manganese as the basic elements, and M as the doping element. On the one hand, by introducing low-cost copper and increasing the content of Mn to replace the cobalt element, the positive electrode material is a nickel-copper-manganese-based positive electrode material, which reduces the cost of the material without reducing the material performance; on the other hand, through element doping, the structural stability of the nickel-copper-manganese base is improved and the gram capacity is promoted, so that the sodium ion battery of the present application has high stability, low cost and excellent electrochemical performance.

[0010] Among them, 0.6≤a≤1.0, for example, it can be 0.6, 0.7, 0.8, 0.9 or 1.0, 0.1≤x≤0.4, for example, it can be 0.1, 0.2, 0.3 or 0.4, 0<y≤0.4, for example, it can be 0.1, 0.2, 0.3, 0.4, 0.3≤z≤0.6, for example, it can be 0.3, 0.4, 0.5 or 0.6,

[0011] The 0<b<0.5 can be, for example, 0.01, 0.025, 0.05, 0.075, 0.1 or 0.4, but is not limited to the listed values. Other unlisted values ​​within the numerical range are also applicable, and preferably 0.02≤b≤0.05.

[0012] The 0<k<0.5 can be, for example, 0.01, 0.025, 0.05, 0.075, 0.1 or 0.4, but is not limited to the listed values. Other unlisted values ​​within the numerical range are also applicable, and preferably 0.02≤k≤0.10.

[0013] The general chemical formula of the sodium ion battery positive electrode material described in the present application satisfies electrical neutrality as a whole and is in a zero-valent state.

[0014] Preferably, M includes any one of Mg, Al, Ca, Cu, Zn, Co, Rb, Sr, Y, Nb, Mo, Cd, La, Ti, V, Cr, Fe, W or Zr, or a combination of at least two thereof.

[0015] In a second aspect, an embodiment of the present application provides a method for preparing the positive electrode material for a sodium ion battery as described in the first aspect, the preparation method comprising the following steps:

[0016] (1) mixing a metal salt solution, an M salt solution, a precipitant solution, and a complexing agent solution into a base solution to perform a coprecipitation reaction to obtain a precursor;

[0017] Wherein, the metal salt solution includes nickel salt, copper salt and manganese salt;

[0018] (2) Mixing and sintering the sodium source with the precursor described in step (1) to obtain the sodium ion battery positive electrode material.

[0019] The sodium ion battery positive electrode material described in the present application is prepared by first preparing a precursor by co-precipitation, and then mixing and sintering with a sodium source. The elements in the obtained sodium ion battery positive electrode material are evenly distributed.

[0020] Preferably, the base liquid in step (1) includes additives.

[0021] The present application also adds additives to the base liquid of the co-precipitation reaction to improve the uniformity of element distribution, inhibit the agglomeration of transition metal elements during precipitation, obtain a positive electrode material precursor with uniform element distribution, increase the utilization rate of active transition metal atoms in the positive electrode material, and help to effectively utilize the capacity of the positive electrode material.

[0022] In addition, the present application adds additives to the base liquid. Compared with the method of adding additives in parallel with other raw materials, the method of adding additives in the present application is simple to operate, easy to control, and has good repeatability.

[0023] Preferably, in the base liquid of step (1), the concentration of the additive is 0-10 g / L, but does not include 0 g / L. For example, it can be 1 g / L, 2.5 g / L, 5 g / L, 7.5 g / L or 10 g / L, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable, preferably 2-5 g / L.

[0024] The content of the additive in the base liquid described in this application is within a specific range, which can further ensure that its effect is exerted. If the concentration of the additive is too high, the carbon content in the precursor product will be too high, lowering the gram capacity of the finished material. If the added concentration is too low, or if no additive is added, the additive cannot effectively play its role.

[0025] Preferably, the additive includes any one of ethylene glycol, glycerol, ethanol or glucose, or a combination of at least two thereof, preferably glycerol and / or glucose.

[0026] The additives of the present application are preferably glycerol and / or glucose, because glycerol and / or glucose have a carbon chain structure of moderate length, can stabilize the material molding, and have a better effect in inhibiting material agglomeration.

[0027] Preferably, the base liquid in step (1) further comprises a complexing agent.

[0028] Preferably, the concentration of the complexing agent in the base solution of step (1) is 1-2 mol / L, for example, 1 mol / L, 1.5 mol / L or 2 mol / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0029] Preferably, the pH of the base solution in step (1) is 8-12, for example, 8, 10 or 12, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0030] Preferably, the coprecipitation reaction in step (1) is carried out in a protective atmosphere, and the protective atmosphere comprises any one of nitrogen, argon or helium, or a combination of at least two of them.

[0031] Preferably, the temperature of the coprecipitation reaction in step (1) is 20-70°C, for example, 20°C, 50°C or 70°C, and the pH is 8-12, for example, 8, 10 or 12, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable.

[0032] Preferably, the mixing method in step (1) includes parallel addition.

[0033] Preferably, the feeding rate of the metal salt solution in step (1) is 4-100 L / h, for example, 4 L / h, 50 L / h or 100 L / h, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0034] Preferably, the feeding rate of the M salt solution in step (1) is 1-20 L / h, for example, 1 L / h, 10 L / h or 20 L / h, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0035] Preferably, the feed rate of the precipitant solution in step (1) is 1-20 L / h, for example, 1 L / h, 10 L / h or 20 L / h, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0036] Preferably, the feeding rate of the complexing agent solution in step (1) is 0.5-10 L / h, for example, 0.5 L / h, 5 L / h or 10 L / h, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0037] Preferably, in the metal salt solution of step (1), the total concentration of metal ions is 0.5-5 mol / L, for example, 0.5 mol / L, 2.5 mol / L or 5 mol / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0038] Preferably, in the M salt solution of step (1), the total concentration of metal ions is 0.01-1 mol / L, for example, 0.01 mol / L, 0.5 mol / L or 1 mol / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0039] Preferably, the concentration of the precipitant solution in step (1) is 2-15 mol / L, for example, 2 mol / L, 10 mol / L or 15 mol / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0040] Preferably, the concentration of the complexing agent solution in step (1) is 4-12 mol / L, for example, 4 mol / L, 7 mol / L or 12 mol / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0041] Preferably, the precipitant solution in step (1) comprises any one of sodium hydroxide, potassium hydroxide, sodium carbonate, sodium bicarbonate or ammonium bicarbonate, or a combination of at least two thereof.

[0042] Preferably, the complexing agent solution in step (1) comprises any one of ammonia water, hydrazine hydrate, acetic acid, oxalic acid or EDTA (ethylenediaminetetraacetic acid), or a combination of at least two thereof.

[0043] Preferably, the sintering temperature in step (2) is 800-1400°C, for example, 800°C, 1000°C, 1200°C or 1400°C, and the sintering time is 10-25h, for example, 10h, 15h, 20h or 25h, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0044] Preferably, the sintering atmosphere in step (2) includes oxygen.

[0045] As a preferred technical solution of the preparation method described in this application, the preparation method comprises the following steps:

[0046] (1) adding a metal salt solution at a feeding rate of 4-100 L / h, an M salt solution at a feeding rate of 1-20 L / h, a precipitant solution at a feeding rate of 1-20 L / h, and a complexing agent solution at a feeding rate of 0.5-10 L / h to the bottom liquid in parallel, and performing a coprecipitation reaction under a protective atmosphere, a temperature of 20-70° C., and a pH of 8-12 to obtain a precursor;

[0047] In the base solution, the concentration of the additive is 0-10 g / L, but excluding 0 g / L, the concentration of the complexing agent is 1-2 mol / L, and the pH of the base solution is 8-12, wherein the additive includes glycerol and / or glucose;

[0048] The metal salt solution includes nickel salt, copper salt and manganese salt, and the total concentration of metal ions is 0.5-5 mol / L; in the M salt solution, the total concentration of metal ions is 0.01-1 mol / L; the concentration of the precipitant solution is 2-15 mol / L; the concentration of the complexing agent solution is 4-12 mol / L;

[0049] (2) Mixing the precursor of step (1) with a sodium source, and then sintering the mixture at a temperature of 800-1400° C. for 10-25 hours in an oxygen atmosphere to obtain the sodium ion battery positive electrode material.

[0050] In a third aspect, an embodiment of the present application provides a sodium ion battery, which includes the sodium ion battery positive electrode material as described in the first aspect.

[0051] Compared with the related art, the embodiments of the present application have the following beneficial effects:

[0052] The embodiment of the present application adopts the low-cost and electrochemically active Cu element to replace the expensive metal Co element, so that the cost of the sodium ion battery positive electrode material is reduced without reducing the material performance. By element doping, the structural stability of the nickel-copper-manganese-based positive electrode material is improved and the gram capacity is promoted, so that the sodium ion battery of the present application has high stability, low cost and excellent electrochemical performance.

[0053] Still other aspects will become apparent upon reading and understanding the accompanying drawings and detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] The accompanying drawings are used to provide a further understanding of the technical solution of this article and constitute a part of the specification. Together with the embodiments of this application, they are used to explain the technical solution of this article and do not constitute a limitation on the technical solution of this article.

[0055] FIG1 is a SEM image of the precursor described in Example 1 of the present application;

[0056] FIG2 is an EPMA diagram of the Cu element in the cross section of the precursor described in Example 1 of the present application;

[0057] FIG3 is an EPMA diagram of the Zr element in the cross section of the precursor described in Example 1 of the present application. DETAILED DESCRIPTION

[0058] The technical solution of the present application is further described below through specific implementation methods. Those skilled in the art should understand that the embodiments are only used to help understand the present application and should not be regarded as specific limitations of the present application.

[0059] Example 1

[0060] This embodiment provides a sodium ion battery positive electrode material, the chemical formula of which is Na 0.96 Ni 0.33 Cu 0.33 Mn 0.34 Zr 0.02 O 2.02 ;

[0061] The preparation method of the sodium ion battery positive electrode material comprises the following steps:

[0062] (1) A metal salt solution is fed at a rate of 40 L / h, and an M salt solution is fed at a rate of 8 L / h, and sodium hydroxide solution and ammonia water are added to the bottom liquid in parallel, wherein the pH value of the coprecipitation reaction system is controlled to be between 10.2 and 10.5, and the ammonia concentration is controlled to be between 0.20 and 0.30 mol / L by controlling the flow rate of the sodium hydroxide solution and the ammonia water. The coprecipitation reaction is carried out in a nitrogen atmosphere at a temperature of 52° C. for 80 h. When the average particle size of the product reaches 9.0 μm, the reaction is stopped, the product is aged for 8 h, centrifuged and washed, and dried at 150° C. to obtain a precursor, the chemical formula of which is [Ni 0.33 Cu 0.33 Mn 0.34 Zr 0.02 ](OH) 2.08 The SEM image of the precursor is shown in FIG1 . The obtained precursor has good sphericity, uniform size, and an average particle size of 9.0 μm. The EPMA image of the cross-section of the precursor for Cu is shown in FIG2 , and the EPMA image of the Zr element is shown in FIG3 . It can be seen from FIG2 and FIG3 that the Cu and Zr elements are evenly distributed inside the precursor particles.

[0063] In the base solution, the concentration of the additive is 2 g / L, the concentration of ammonia water is 0.5 mol / L, the pH of the base solution is 11.2, wherein the additive is glycerol;

[0064] The metal salt solution includes nickel nitrate, copper chloride and manganese nitrate in a formulated amount, and the total concentration of metal ions is 2 mol / L; the M salt solution is a zirconium sulfate solution with a total metal ion concentration of 0.2 mol / L; the concentration of the sodium hydroxide solution is 10 mol / L; the concentration of the ammonia water is 8 mol / L;

[0065] (2) The precursor of step (1) is mixed with sodium carbonate in a molar ratio of 1.05:1, and then sintered at a temperature of 1000° C. for 16 h in an oxygen atmosphere, and the obtained mixture is ground and sieved to obtain the sodium ion battery positive electrode material.

[0066] Example 2

[0067] This embodiment provides a sodium ion battery positive electrode material. The general chemical formula of the sodium ion battery positive electrode material is Na 0.94 Ni 0.30 Cu 0.15 Mn 0.55 Fe 0.04 O 2.03 ;

[0068] The preparation method of the sodium ion battery positive electrode material comprises the following steps:

[0069] (1) A metal salt solution is fed at a rate of 20 L / h, and an M salt solution is fed at a rate of 4 L / h, and sodium hydroxide solution and ammonia water are added to the bottom liquid in parallel, wherein the pH value of the reaction system is controlled to be between 9.6 and 9.8, and the ammonia concentration is controlled to be between 0.15 and 0.25 mol / L by controlling the flow rate of the sodium hydroxide solution and the ammonia water. Then, a coprecipitation reaction is carried out in a nitrogen atmosphere at a temperature of 45° C. for 50 hours. When the average particle size of the product reaches 6.0 μm, the reaction is stopped, the mixture is aged for 12 hours, centrifuged and washed, and dried at 130° C. to obtain a precursor, the chemical formula of which is [Ni 0.30 Cu 0.15 Mn 0.55 Fe 0.04 ](OH) 2.08 ;

[0070] In the base solution, the concentration of the additive is 3 g / L, the concentration of ammonia water is 0.3 mol / L, the pH of the base solution is 11, wherein the additive is glycerol;

[0071] The metal salt solution includes nickel nitrate, copper chloride and manganese nitrate in a formulated amount, and the total concentration of metal ions is 1.5 mol / L; the M salt solution is a ferrous sulfate solution with a total metal ion concentration of 0.3 mol / L; the concentration of the sodium hydroxide solution is 10 mol / L; the concentration of the ammonia water is 8 mol / L;

[0072] (2) The precursor of step (1) is mixed with sodium carbonate in a molar ratio of 1.03:1, and then sintered at a temperature of 900° C. for 18 hours in an oxygen atmosphere to obtain the sodium ion battery positive electrode material.

[0073] Example 3

[0074] This embodiment provides a sodium ion battery positive electrode material. The chemical composition of the sodium ion battery positive electrode material is Na 0.96 Ni 0.33 Cu 0.33 Mn 0.34 Zr 0.02 O 2.02 ;

[0075] The preparation method of the sodium ion battery positive electrode material comprises the following steps:

[0076] (1) adding a metal salt solution at a feeding rate of 80 L / h and an M salt solution at a feeding rate of 20 L / h, a sodium hydroxide solution and an ammonia solution in parallel to the bottom liquid, wherein the pH value of the reaction system is controlled between 11.5 and 11.7 and the ammonia concentration is controlled between 0.25 and 0.35 mol / L by controlling the flow rate of the sodium hydroxide solution and the ammonia solution, and then carrying out a coprecipitation reaction in a nitrogen atmosphere at a temperature of 65° C. for 50 h. When the average particle size of the product reaches 5.0 μm, the reaction is stopped, aged for 8 h, centrifuged and washed, and dried at 150° C. to obtain a precursor;

[0077] In the base solution, the concentration of the additive is 5 g / L, the concentration of ammonia water is 1 mol / L, the pH of the base solution is 8, wherein the additive is glycerol;

[0078] The metal salt solution includes nickel nitrate, copper chloride and manganese nitrate in a formulated amount, and the total concentration of metal ions is 1 mol / L; the M salt solution is a zirconium sulfate solution with a total concentration of metal ions of 0.1 mol / L; the concentration of the sodium hydroxide solution is 2 mol / L; the concentration of the ammonia water is 4 mol / L;

[0079] (2) The precursor of step (1) is mixed with sodium carbonate in a molar ratio of 1.05:1, and then sintered at a temperature of 800° C. for 25 hours in an oxygen atmosphere to obtain the sodium ion battery positive electrode material.

[0080] Example 4

[0081] This embodiment provides a sodium ion battery positive electrode material, the chemical formula of which is Na 0.96 Ni 0.33 Cu 0.33 Mn 0.34 Zr 0.02 O2.02 ;

[0082] The preparation method of the sodium ion battery positive electrode material comprises the following steps:

[0083] (1) adding a metal salt solution at a feeding rate of 10 L / h, an M salt solution at a feeding rate of 3 L / h, a sodium hydroxide solution, and an ammonia solution to the bottom liquid in parallel, wherein the pH value of the coprecipitation reaction system is controlled to be between 10.2 and 10.5 and the ammonia concentration is controlled to be between 0.20 and 0.30 mol / L by controlling the flow rate of the sodium hydroxide solution and the ammonia solution, and the coprecipitation reaction is carried out in a nitrogen atmosphere at a temperature of 30° C. for 80 hours. When the average particle size of the product reaches 9.0 μm, the reaction is stopped, the product is aged for 8 hours, centrifuged and washed, and dried at 150° C. to obtain a precursor;

[0084] In the base solution, the concentration of the additive is 5 g / L, the concentration of ammonia water is 2 mol / L, the pH of the base solution is 12, wherein the additive is glycerol;

[0085] The metal salt solution includes nickel nitrate, copper chloride and manganese nitrate in a formulated amount, and the total concentration of metal ions is 5 mol / L; the M salt solution is a zirconium sulfate solution with a total metal ion concentration of 0.5 mol / L; the concentration of the sodium hydroxide solution is 15 mol / L; the concentration of the ammonia water is 12 mol / L;

[0086] (2) The precursor of step (1) is mixed with sodium carbonate in a molar ratio of 1.05:1, and then sintered at a temperature of 1400° C. for 10 hours in an oxygen atmosphere to obtain the sodium ion battery positive electrode material.

[0087] Example 5

[0088] This embodiment provides a sodium ion battery positive electrode material. The sodium ion battery positive electrode material is the same as that in Example 1 except that in the preparation method thereof, the concentration of the additive in step (1) is 10 g / L to adapt the obtained sodium ion battery positive electrode material.

[0089] Example 6

[0090] This embodiment provides a sodium ion battery positive electrode material. The sodium ion battery positive electrode material is the same as that in Example 1 except that in the preparation method thereof, the concentration of the additive in step (1) is 15 g / L to adapt the obtained sodium ion battery positive electrode material.

[0091] Example 7

[0092] This embodiment provides a sodium ion battery positive electrode material. The sodium ion battery positive electrode material is the same as Example 1 except that in the preparation method thereof, the base liquid in step (1) does not contain an additive, but the additive is added to the base liquid at a flow rate of 0.2 L / h together with the metal salt solution, M salt solution, sodium hydroxide solution and ammonia water to make the adaptability of the obtained sodium ion battery positive electrode material change.

[0093] Example 8

[0094] This embodiment provides a sodium ion battery positive electrode material. The sodium ion battery positive electrode material is the same as that in Example 1 except that in the preparation method thereof, the base liquid in step (1) does not contain an additive, so that the adaptability of the obtained sodium ion battery positive electrode material changes.

[0095] Example 9

[0096] This embodiment provides a sodium ion battery positive electrode material. The sodium ion battery positive electrode material is the same as that in Example 1 except that in the preparation method thereof, the additive in the base liquid in step (1) is ethanol, which changes the adaptability of the obtained sodium ion battery positive electrode material.

[0097] Example 10

[0098] This embodiment provides a sodium ion battery positive electrode material. The sodium ion battery positive electrode material is the same as that in Example 1 except that in the preparation method thereof, the additive in the base liquid in step (1) is ethylene glycol, which changes the adaptability of the obtained sodium ion battery positive electrode material.

[0099] Example 11

[0100] This embodiment provides a sodium ion battery positive electrode material, the chemical formula of which is Na 0.96 Ni 0.33 Cu 0.33 Mn 0.34 Zr 0.08 O 2.14 Except for this, the rest are the same as in Example 1.

[0101] Example 12

[0102] This embodiment provides a sodium ion battery positive electrode material, the chemical formula of which is Na 0.96 Ni 0.33 Cu 0.33 Mn 0.34 Zr 0.015 O 2.01 Except for this, the rest are the same as in Example 1.

[0103] Comparative Example 1

[0104] This comparative example provides a sodium ion battery positive electrode material. The sodium ion battery positive electrode material is the same as Example 1 except that in its preparation method, the M salt solution is not added during the coprecipitation reaction in step (1), which causes the chemical formula of the sodium ion battery positive electrode material to change accordingly.

[0105] Comparative Example 2

[0106] This comparative example provides a sodium ion battery positive electrode material. The sodium ion battery positive electrode material is the same as Example 1 except that in its preparation method, no M salt solution is added during the coprecipitation reaction in step (1), and the base liquid does not contain additives, which causes the chemical formula of the sodium ion battery positive electrode material to change accordingly.

[0107] Comparative Example 3

[0108] This comparative example provides a sodium ion battery positive electrode material. The sodium ion battery positive electrode material is the same as Example 1 except that in its preparation method, the copper chloride in step (1) is replaced by cobalt chloride in equal moles, so that the chemical formula of the sodium ion battery positive electrode material changes accordingly.

[0109] The sodium ion battery positive electrode materials obtained in the above examples and comparative examples were prepared into positive electrode sheets at 25°C, and then the metal sodium sheet was used as the negative electrode to assemble into CR2032 button batteries. Then, the discharge current density was 10 mA g in the voltage range of 2.0-4.0 V. -1 The electrochemical performance test was carried out under the conditions of , and the test results are shown in Table 1 below:

[0110] Table 1

[0111] From Table 1 we can see that:

[0112] The sodium ion battery material of the present application has low cost and excellent electrochemical properties. It can be seen from Example 1 and Comparative Examples 1-2 that the addition of the doping element of the present application can further improve the gram capacity of the material. During the coprecipitation reaction, the addition of additives to the base liquid can further improve the uniformity of element dispersion, thereby further improving the performance. Moreover, from the comparison of the obtained gram capacities, it can be seen that the doping element of the present application and the addition of additives to the base liquid have a synergistic effect. It can be seen from Example 1 and Comparative Example 3 that the use of Cu to replace Co in the present application does not reduce the performance of the material. It can be seen from Example 1 and Examples 5-10 that the concentration, type and addition method of the additive will affect the effect of the additive, thereby affecting the material performance. It can be seen from Example 1 and Examples 11-12 that the doping amount of the doping element of the present application will affect the gram capacity.

[0113] In summary, the present application provides a sodium ion battery positive electrode material, a preparation method and an application thereof. The sodium ion battery positive electrode material introduces low-cost Cu and appropriately increases the Mn content to replace the expensive metal Co, thereby significantly reducing the battery cost without sacrificing battery performance. The sodium ion battery positive electrode material described in the present application has the advantages of high energy density, good safety and low production cost.

[0114] The above description is only a specific implementation method of the present application, but the protection scope of the present application is not limited thereto. Those skilled in the art should understand that any changes or replacements that can be easily thought of by those skilled in the art within the technical scope disclosed in the present application fall within the protection scope and disclosure scope of the present application.

Claims

1. A sodium ion battery positive electrode material, wherein: The chemical formula of the sodium ion battery positive electrode material is Na a Ni x Cu y Mn z M b O 2+k , wherein 0.6≤a≤1.0, 0.1≤x≤0.4, 0<y≤0.4, 0.3≤z≤0.6, 0<b<0.5, 0<k<0.5, and M includes metal elements derived from laterite nickel ore.

2. The sodium ion battery positive electrode material according to claim 1, wherein The M includes any one of Mg, Al, Ca, Cu, Zn, Co, Rb, Sr, Y, Nb, Mo, Cd, La, Ti, V, Cr, Fe, W or Zr, or a combination of at least two thereof.

3. The sodium ion battery positive electrode material according to claim 1 or 2, wherein 0.02≤b≤0.05。 4. The sodium ion battery positive electrode material according to any one of claims 1 to 3, wherein 0.02≤k≤0.10。 5. A method for preparing a positive electrode material for a sodium ion battery according to any one of claims 1 to 4, comprising the following steps: (1) mixing a metal salt solution, an M salt solution, a precipitant solution and a complexing agent solution into a base solution to perform a coprecipitation reaction to obtain a precursor; in, The metal salt solution includes nickel salt, copper salt and manganese salt; (2) Mixing and sintering the sodium source with the precursor in step (1) to obtain the sodium ion battery positive electrode material.

6. The preparation method according to claim 5, wherein: The base liquid in step (1) includes additives.

7. The preparation method according to claim 5 or 6, wherein: In the base solution of step (1), the concentration of the additive is 0-10 g / L, but excluding 0 g / L, and preferably 2-5 g / L.

8. The preparation method according to any one of claims 5 to 7, wherein: The additive includes any one of ethylene glycol, glycerol, ethanol or glucose or a combination of at least two thereof, preferably glycerol and / or glucose.

9. The preparation method according to any one of claims 6 to 8, wherein: The base solution in step (1) also includes a complexing agent. Preferably, in the base solution of step (1), the concentration of the complexing agent is 1-2 mol / L; Preferably, the pH of the base solution in step (1) is 8-12.

10. The preparation method according to any one of claims 5 to 9, wherein: The coprecipitation reaction in step (1) is carried out in a protective atmosphere; Preferably, the temperature of the coprecipitation reaction in step (1) is 20-70° C. and the pH is 8-12; Preferably, the mixing method in step (1) includes parallel flow addition.

11. The preparation method according to any one of claims 5 to 10, wherein: The feeding rate of the metal salt solution in step (1) is 4-100 L / h; Preferably, the feeding rate of the M salt solution in step (1) is 1-20 L / h; Preferably, the feed rate of the precipitant solution in step (1) is 1-20 L / h; Preferably, the feeding rate of the complexing agent solution in step (1) is 0.5-10 L / h.

12. The preparation method according to any one of claims 5 to 11, wherein: In the metal salt solution of step (1), the total concentration of metal ions is 0.5-5 mol / L; Preferably, in the M salt solution of step (1), the total concentration of metal ions is 0.01-1 mol / L; Preferably, the concentration of the precipitant solution in step (1) is 2-15 mol / L; Preferably, the concentration of the complexing agent solution in step (1) is 4-12 mol / L.

13. The preparation method according to any one of claims 5 to 12, wherein: The precipitant solution in step (1) comprises any one of sodium hydroxide, potassium hydroxide, sodium carbonate, sodium bicarbonate or ammonium bicarbonate, or a combination of at least two thereof; Preferably, the complexing agent solution in step (1) comprises any one of ammonia water, hydrazine hydrate, acetic acid, oxalic acid or EDTA, or a combination of at least two thereof; Preferably, the sintering temperature in step (2) is 800-1400° C. and the sintering time is 10-25 h; Preferably, the sintering atmosphere in step (2) includes oxygen.

14. The preparation method according to any one of claims 5 to 13, comprising the steps of: (1) adding a metal salt solution at a feeding rate of 4-100 L / h, an M salt solution at a feeding rate of 1-20 L / h, a precipitant solution at a feeding rate of 1-20 L / h, and a complexing agent solution at a feeding rate of 0.5-10 L / h to the bottom liquid in parallel, and performing a coprecipitation reaction under a protective atmosphere, a temperature of 20-70° C., and a pH of 8-12 to obtain a precursor; In the base solution, the concentration of the additive is 0-10 g / L, but not including 0 g / L, the concentration of the complexing agent is 1-2 mol / L, and the pH of the base solution is 8-12, wherein, The additives include glycerol and / or glucose; The metal salt solution includes nickel salt, copper salt and manganese salt, and the total concentration of metal ions is 0.5-5 mol / L; in the M salt solution, the total concentration of metal ions is 0.01-1 mol / L; the concentration of the precipitant solution is 2-15 mol / L; the concentration of the complexing agent solution is 4-12 mol / L; (2) Mixing a sodium source with the precursor of step (1), and then sintering at a temperature of 800-1400° C. for 10-25 hours in an oxygen atmosphere to obtain the sodium ion battery positive electrode material.

15. A sodium ion battery, wherein: The sodium ion battery comprises the sodium ion battery positive electrode material according to any one of claims 1 to 4.

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