A cathode precursor material for a sodium-ion battery, a preparation method thereof, and an application thereof

Abstract

The present invention provides a cathode precursor material for a sodium-ion battery, a preparation method thereof and an application. The preparation method includes the following steps: mixing a metal salt solution, a complexing agent solution and a precipitating agent solution into a bottom liquid to carry out a coprecipitation reaction to obtain the cathode precursor material for the sodium-ion battery; wherein, the bottom liquid includes an organic additive, and the metal salt solution includes a nickel salt, a magnesium salt and a manganese salt. By controlling the conditions of the coprecipitation reaction, the preparation method of the present invention introduces magnesium element to reduce the content of nickel, and enables the low-nickel precursor material to be synthesized by the coprecipitation method under the action of the organic additive, further reducing the cost of the cathode material precursor for the sodium-ion battery while ensuring the performance of the precursor.

Description

Technical Field

[0001] The present invention belongs to the technical field of batteries, and relates to a cathode precursor material for a sodium-ion battery, a preparation method thereof, and an application thereof. Background Art

[0002] Currently, lithium-ion batteries (LIBs) are ubiquitous in all modern portable electronic devices (such as mobile phones and laptops), and can also power hybrid electric vehicles and other large devices. With the rapid increase in the price of lithium, the cost of LIBs has been greatly increased. Sodium resources are abundant in the earth's crust, and the cost is much lower than that of lithium. Moreover, sodium-ion batteries (NIBs) have a similar working mechanism to LIBs, so NIBs have been widely studied.

[0003] Layered oxide cathodes are the most industrially favorable type of NIB cathodes. Their structure is the same as that of ternary cathode materials in lithium-ion batteries, and the production equipment for LIB ternary cathodes can be used. Although the theoretical cost of NIBs is much lower than that of LIBs, due to the relatively high Ni content in current layered oxide cathodes, it is not conducive to reducing the cost of NIBs, and only the solid-phase method can obtain NIB cathodes with a relatively low Ni content and a relatively high Mg content.

[0004] For example, CN 116387504A discloses a multi-component O3-type layered sodium-ion battery cathode material and a preparation method thereof. The chemical formula of the cathode material is Na x Ni a Cu b Fe c Mn d Ti e M f O2, where 0.15 ≤ a ≤ 0.35, and 0M is one or more of Li, Mg, Zn, Al, Co, Sn, V, Zr, La, Nb. The preparation method is a solid-phase method, including: mixing the required stoichiometric amounts of sodium carbonate, nickel oxide, copper oxide, iron oxide, manganese dioxide, titanium dioxide, and the oxide of M in proportion to form a precursor, and then sintering to prepare the cathode material. That is, it precisely uses the solid-phase method with high energy consumption and difficult control to prepare a sodium battery cathode material with a relatively low Ni content.

[0005] Based on the above research, a preparation method for a cathode precursor material of a sodium-ion battery is needed. The preparation method can prepare a precursor material with a low Ni content and a high Mg content through a co-precipitation method, thereby reducing the cost of the sodium battery cathode material. Summary of the Invention

[0006] The object of the present invention is to provide a cathode precursor material for a sodium-ion battery, a preparation method thereof and an application. By controlling the conditions of the coprecipitation reaction, magnesium element is introduced to reduce the nickel content, so that the low-nickel precursor material can be synthesized by the coprecipitation method, while ensuring the performance of the precursor, the cost of the cathode precursor material for the sodium-ion battery is further reduced.

[0007] To achieve the object of this invention, the following technical solutions are adopted:

[0008] In the first aspect, the present invention provides a preparation method of a cathode precursor material for a sodium-ion battery, and the preparation method includes the following steps:

[0009] Mix a metal salt solution, a complexing agent solution and a precipitant solution into a bottom liquid, and carry out a coprecipitation reaction to obtain the cathode precursor material for the sodium-ion battery;

[0010] Wherein, the bottom liquid includes an organic additive, and the metal salt solution includes a nickel salt, a magnesium salt and a manganese salt.

[0011] The present invention reduces the usage amount of the nickel salt by adding the magnesium salt, and makes the metal salts coprecipitate simultaneously by adding the organic additive to the bottom liquid, solving the problem that only the solid-phase method can be used to obtain a precursor material with a lower Ni content and a higher Mg content. Therefore, the cost of the sodium-ion battery is reduced, and the performance of the sodium-ion battery is ensured at the same time.

[0012] Preferably, the complexing agent solution includes more than two kinds of complexing agents with different types.

[0013] Preferably, the complexing agent solution includes a combination of at least two of an ammonia water solution, an oxalic acid solution, a sodium oxalate solution, a citric acid solution, a sodium citrate solution, a lactic acid solution or a tartaric acid solution. Typical but non-limiting combinations include a combination of an ammonia water solution and an oxalic acid solution, a combination of a sodium oxalate solution and a citric acid solution, a combination of a lactic acid solution and a tartaric acid solution. Preferably, it is a combination of at least two of a citric acid solution, a lactic acid solution or a tartaric acid solution.

[0014] By using at least two complexing agents for coprecipitation, the present invention can further promote the coprecipitation of multiple metal ions. If only one complexing agent is used, it is impossible to ensure the coprecipitation of multiple metal ions at the same time, which will affect the purity of the precursor material and the performance of the sodium-ion battery.

[0015] Preferably, in the complexing agent solution, the concentration of any one complexing agent is 0.01 - 0.3 mol / L. For example, it can be 0.01 mol / L, 0.05 mol / L, 0.1 mol / L, 0.15 mol / L, 0.2 mol / L, 0.25 mol / L or 0.3 mol / L. However, it is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0016] Preferably, in the complexing agent solution, the molar ratio of any two complexing agents is (1 - 10):(1 - 10). For example, it can be 1:1, 1:10, 2:7, 4:5, 2:3 or 10:1. However, it is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0017] Based on the use of more than two complexing agents in the present invention, the molar ratio between the complexing agents should also be within a reasonable range. If the addition amount of a certain complexing agent in the combined complexing agent is too small or too large, the function of the combined complexing agent cannot be effectively exerted.

[0018] Preferably, the organic additive includes any one or a combination of at least two of ethanol, ethylene glycol, glycerol or dipropylene glycol, and is preferably glycerol and / or dipropylene glycol.

[0019] By adding an organic additive to the base solution in the present invention, on the one hand, it can promote the coprecipitation of metal ions, and on the other hand, it can improve the uniformity of element distribution. Moreover, the organic additive of the present invention preferably uses glycerol and / or dipropylene glycol, which can make the crystal nuclei formed at startup smaller in particle size and more uniform in distribution.

[0020] Preferably, the base solution further includes water, and the mass ratio of the water to the organic additive is (1 - 10):(0 - 1), but does not include (1 - 10):0. For example, it can be 1:1, 5:1, 10:1 or 5:0.5. However, it is not limited to the listed values, and other unlisted values within the numerical range are equally applicable, and is preferably (1 - 10):(0.2 - 1).

[0021] The organic additive of the present invention can promote the exertion of its function within a reasonable range. If the amount of the organic additive in the base solution is too small, the coprecipitation effect between metal ions will decrease; if the amount of the organic additive in the base solution is too large, the cost will increase, which is not conducive to large-scale production.

[0022] Preferably, the base solution further includes sodium hydroxide and ammonia water.

[0023] Preferably, the pH of the base solution is 10 - 11.8. For example, it can be 10, 10.5, 11, 11.5 or 11.8. However, it is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0024] Preferably, in the bottom liquid, the concentration of ammonia water is 0.01 - 0.3 mol / L, for example, it can be 0.01 mol / L, 0.1 mol / L, 0.2 mol / L or 0.3 mol / L, but not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0025] Preferably, the metal salt solution further includes an iron salt.

[0026] Preferably, the nickel salt includes any one or a combination of at least two of nickel nitrate, nickel sulfate or nickel chloride.

[0027] Preferably, the iron salt includes ferrous sulfate and / or ferrous chloride.

[0028] Preferably, the manganese salt includes any one or a combination of at least two of manganese nitrate, manganese sulfate or manganese chloride.

[0029] Preferably, the magnesium salt includes any one or a combination of at least two of magnesium nitrate, magnesium sulfate or manganese chloride.

[0030] Preferably, in the metal salt solution, the molar ratio of nickel ions, iron ions, manganese ions and magnesium ions is x:y:z:(1 - x - y - z), where x is 0.1 - 0.2, for example, it can be 0.1, 0.15 or 0.2, y is 0.10 - 0.34, for example, it can be 0.10, 0.20, 0.30 or 0.34, z is 0.34 - 0.5, for example, it can be 0.34, 0.4 or 0.5, but not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0031] Preferably, in the metal salt solution, the total metal ion concentration is 2 - 4 mol / L, for example, it can be 2 mol / L, 3 mol / L or 4 mol / L, but not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0032] Preferably, the concentration of the precipitant solution is 1 - 3 mol / L, for example, it can be 1 mol / L, 2 mol / L or 3 mol / L, but not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0033] Preferably, the precipitant solution includes a sodium hydroxide solution.

[0034] Preferably, the temperature of the coprecipitation reaction is 40 - 70 °C, such as 40 °C, 50 °C, 60 °C or 70 °C, the pH is 8.0 - 11.0, such as 8.0, 9.0, 10.0 or 11.0, and the time is 50 - 100 h, such as 50 h, 70 h, 90 h or 100 h. However, it is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0035] Preferably, the coprecipitation reaction is carried out in nitrogen.

[0036] Preferably, the coprecipitation reaction is carried out under stirring, and the rotation speed of the stirring is 200 - 400 r / min, such as 200 r / min, 300 r / min or 400 r / min. However, it is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0037] Preferably, the mixing method is co-current addition.

[0038] Preferably, after the coprecipitation reaction, washing, drying and sieving treatments are also carried out to obtain the positive electrode precursor material for the sodium-ion battery.

[0039] As a preferred technical solution of the preparation method of the present invention, the preparation method includes the following steps:

[0040] Mix a metal salt solution, a complexing agent solution and a precipitating agent solution into a bottom solution, and carry out a coprecipitation reaction for 50 - 100 h under a nitrogen atmosphere, at a temperature of 40 - 70 °C, a pH of 8.0 - 11.0 and a stirring speed of 200 - 400 r / min to obtain the positive electrode precursor material for the sodium-ion battery;

[0041] The pH of the bottom solution is 10 - 11.8, and it includes water, an organic additive, sodium hydroxide and ammonia water. Among them, the organic additive includes any one or a combination of at least two of ethanol, ethylene glycol, glycerol or dipropylene glycol. The mass ratio of water to the organic additive is (1 - 10):(0 - 1), but does not include (1 - 10):0. In the bottom solution, the concentration of ammonia water is 0.01 - 0.3 mol / L;

[0042] The complexing agent solution includes a combination of at least two of ammonia water solution, oxalic acid solution, sodium oxalate solution, citric acid solution, sodium citrate solution, lactic acid solution or tartaric acid solution. In the complexing agent solution, the concentration of any one complexing agent is 0.01 - 0.3 mol / L, and the molar ratio of any two complexing agents is (1 - 10):(1 - 10);

[0043] In the metal salt solution, the molar ratio of nickel ions, iron ions, manganese ions and magnesium ions is x:y:z:(1 - x - y - z), where x is 0.1 - 0.2, y is 0.10 - 0.34, z is 0.34 - 0.5, and the total metal ion concentration is 2 - 4 mol / L.

[0044] In a second aspect, the present invention provides a sodium ion battery cathode precursor material, which is prepared by the preparation method described in the first aspect.

[0045] Preferably, the chemical formula of the sodium ion battery cathode precursor material is Ni x Fe y Mn z Mg 1-x-y-z (OH)2, where x is 0.1 - 0.2, for example, it can be 0.1, 0.15 or 0.2, y is 0.10 - 0.34, for example, it can be 0.10, 0.20, 0.30 or 0.34, z is 0.34 - 0.5, for example, it can be 0.34, 0.4 or 0.5, but not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0046] In a third aspect, the present invention provides a sodium ion battery cathode material, which is prepared from a sodium source and the sodium ion battery cathode precursor material of the second aspect.

[0047] Preferably, the sodium source is sodium carbonate, and the molar ratio of the sodium ion battery cathode precursor material to sodium carbonate is 1:(0.45 - 0.5), for example, it can be 1:0.45, 1:0.48 or 1:0.5, but not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0048] Preferably, the chemical formula of the sodium ion battery cathode material is Na w Ni x Fe y Mn z Mg (1-x-y-z) O2, where w is 0.8 - 1, for example, it can be 0.8, 0.9 or 1, x is 0.1 - 0.2, for example, it can be 0.1, 0.15 or 0.2, y is 0.10 - 0.34, for example, it can be 0.10, 0.20, 0.30 or 0.34, z is 0.34 - 0.5, for example, it can be 0.34, 0.4 or 0.5, but not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0049] In a fourth aspect, the present invention provides a sodium ion battery, which includes the sodium ion battery cathode material described in the third aspect.

[0050] Compared with the prior art, the present invention has the following beneficial effects:

[0051] By introducing magnesium salts, the present invention reduces the usage amount of nickel salts, and by adding organic additives to the bottom liquid, the metal salts are co-precipitated simultaneously, solving the problem that only the solid-phase method can be used to obtain a precursor material with a lower Ni content and a higher Mg content. Therefore, the cost of the sodium-ion battery is reduced, and the performance of the sodium-ion battery is ensured at the same time. Specific embodiments

[0052] The technical solution of the present invention will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only for helping to understand the present invention and should not be regarded as specific limitations on the present invention.

[0053] Example 1

[0054] This example provides a preparation method of a cathode precursor material for a sodium-ion battery. The preparation method includes the following steps:

[0055] (1) Mix nickel sulfate, ferrous sulfate, manganese sulfate and magnesium sulfate to prepare a metal salt solution with a total metal ion concentration of 2 mol / L. In the metal salt solution, the molar ratio of nickel ions, iron ions, manganese ions and magnesium ions is 0.17:0.17:0.5:0.16;

[0056] (2) Add the complexing agent solution, the sodium hydroxide solution with a concentration of 2 mol / L and the metal salt solution described in step (1) into the reaction kettle containing the bottom liquid in a co-current manner, and carry out a co-precipitation reaction for 80 h under a nitrogen atmosphere and at a temperature of 60 °C. During the co-precipitation reaction, the pH is maintained within the range of 9-10, and the stirring speed is maintained within the range of 360-400 r / min. After the reaction is completed, after washing, drying and sieving, the sodium-ion battery cathode precursor material with the structural formula of Ni 0.17 Fe 0.17 Mn 0.5 Mg 0.16 (OH)2 is obtained;

[0057] The pH of the bottom liquid is 11.1, and it includes water, an organic additive, sodium hydroxide and ammonia water. Among them, the organic additive is ethanol, the mass ratio of water to the organic additive is 8:1, and in the bottom liquid, the concentration of ammonia water is 0.2 mol / L;

[0058] The complexing agent solution is a mixed solution of ammonia water with a concentration of 0.02 mol / L and sodium oxalate with a concentration of 0.2 mol / L. In the complexing agent solution, the molar ratio of ammonia water to sodium oxalate is 1:10.

[0059] Example 2

[0060] This embodiment provides a method for preparing a cathode precursor material for a sodium-ion battery. The preparation method includes the following steps:

[0061] (1) Mix nickel sulfate, ferrous sulfate, manganese sulfate, and magnesium sulfate to prepare a metal salt solution with a total metal ion concentration of 4 mol / L. In the metal salt solution, the molar ratio of nickel ions, iron ions, manganese ions, and magnesium ions is 0.1:0.2:0.4:0.3;

[0062] (2) Add the complexing agent solution, sodium hydroxide solution with a concentration of 3 mol / L, and the metal salt solution described in step (1) into the reaction kettle containing the bottom liquid in a co-current manner. Under a nitrogen atmosphere and at a temperature of 40 °C, carry out a co-precipitation reaction for 100 h. During the co-precipitation reaction, the pH is maintained within the range of 10 - 11, and the stirring speed is maintained within the range of 200 - 300 r / min. After the co-precipitation reaction is completed, after washing, drying, and sieving, the sodium-ion battery cathode precursor material with the structural formula Ni 0.1 Fe 0.2 Mn 0.4 Mg 0.3 (OH)2 is obtained;

[0063] The pH of the bottom liquid is 11.8, and it includes water, an organic additive, sodium hydroxide, and ammonia water. Among them, the organic additive is ethanol, the mass ratio of water to the organic additive is 1:0.2, and in the bottom liquid, the concentration of ammonia water is 0.3 mol / L;

[0064] The complexing agent solution is a mixed solution of ammonia water with a concentration of 0.2 mol / L and sodium oxalate with a concentration of 0.02 mol / L. In the complexing agent solution, the molar ratio of ammonia water to sodium oxalate is 10:1.

[0065] Example 3

[0066] This embodiment provides a method for preparing a cathode precursor material for a sodium-ion battery. The preparation method includes the following steps:

[0067] (1) Mix nickel sulfate, ferrous sulfate, manganese sulfate, and magnesium sulfate to prepare a metal salt solution with a total metal ion concentration of 2 mol / L. In the metal salt solution, the molar ratio of nickel ions, iron ions, manganese ions, and magnesium ions is 0.17:0.17:0.5:0.16;

[0068] (2) The complexing agent solution, the sodium hydroxide solution with a concentration of 1 mol / L, and the metal salt solution described in step (1) are added into the reaction kettle containing the bottom liquid in a co-current manner. Under a nitrogen atmosphere and at a temperature of 70 °C, a coprecipitation reaction is carried out for 50 h. During the coprecipitation reaction, the pH is maintained within the range of 9.0 - 10.0, and the stirring speed is maintained within the range of 360 - 400 r / min. After the coprecipitation reaction is completed, after washing, drying, and sieving, the sodium-ion battery cathode precursor material with the structural formula Ni 0.17 Fe 0.17 Mn 0.5 Mg 0.16 (OH)2 is obtained;

[0069] The pH of the bottom liquid is 10, and it includes water, an organic additive, sodium hydroxide, and ammonia water. Among them, the organic additive is ethanol, the mass ratio of water to the organic additive is 1:1, and in the bottom liquid, the concentration of ammonia water is 0.01 mol / L;

[0070] The complexing agent solution is a mixed solution of ammonia water with a concentration of 0.02 mol / L and sodium oxalate with a concentration of 0.2 mol / L. In the complexing agent solution, the molar ratio of ammonia water to sodium oxalate is 1:10.

[0071] Example 4

[0072] This example provides a preparation method of a sodium-ion battery cathode precursor material. Except that the organic additive described in step (2) is glycerol, the rest are the same as in Example 1.

[0073] Example 5

[0074] This example provides a preparation method of a sodium-ion battery cathode precursor material. Except that the organic additive described in step (2) is dipropylene glycol, the rest are the same as in Example 1.

[0075] Example 6

[0076] This example provides a preparation method of a sodium-ion battery cathode precursor material. Except that the mass ratio of water to the organic additive described in step (2) is 8:0.1, the rest are the same as in Example 1.

[0077] Example 7

[0078] This example provides a preparation method of a sodium-ion battery cathode precursor material. Except that the mass ratio of water to the organic additive described in step (2) is 8:2, the rest are the same as in Example 1.

[0079] Example 8

[0080] This embodiment provides a method for preparing a cathode precursor material for a sodium-ion battery. Except that the molar ratio of ammonia water to sodium oxalate in step (2) is 1:16, and the concentration of sodium oxalate in the complexing agent solution changes accordingly, the rest are the same as in Embodiment 1.

[0081] Embodiment 9

[0082] This embodiment provides a method for preparing a cathode precursor material for a sodium-ion battery. Except that the molar ratio of ammonia water to sodium oxalate in step (2) is 0.5:10, and the concentration of ammonia water in the complexing agent solution changes accordingly, the rest are the same as in Embodiment 1.

[0083] Embodiment 10

[0084] This embodiment provides a method for preparing a cathode precursor material for a sodium-ion battery. Except that the complexing agent solution in step (2) is a mixed solution of lactic acid with a concentration of 0.02 mol / L and tartaric acid with a concentration of 0.2 mol / L, the rest are the same as in Embodiment 1.

[0085] Embodiment 11

[0086] This embodiment provides a method for preparing a cathode precursor material for a sodium-ion battery. Except that the complexing agent solution in step (2) is a mixed solution of citric acid with a concentration of 0.02 mol / L and lactic acid with a concentration of 0.2 mol / L, the rest are the same as in Embodiment 1.

[0087] Embodiment 12

[0088] This embodiment provides a method for preparing a cathode precursor material for a sodium-ion battery. Except that the complexing agent solution in step (2) is an ammonia water solution with a concentration of 0.22 mol / L, the rest are the same as in Embodiment 1.

[0089] Embodiment 13

[0090] This embodiment provides a method for preparing a cathode precursor material for a sodium-ion battery. Except that the complexing agent solution in step (2) is a sodium oxalate solution with a concentration of 0.22 mol / L, the rest are the same as in Embodiment 1.

[0091] Comparative Example 1

[0092] This comparative example provides a method for preparing a cathode precursor material for a sodium-ion battery. Except that the bottom liquid in step (2) does not include an organic additive, the rest are the same as in Embodiment 1.

[0093] Comparative Example 2

[0094] This comparative example provides a method for preparing a cathode precursor material for a sodium-ion battery. Except that the bottom liquid in step (2) does not include an organic additive, and an organic additive solution with a concentration of 0.2 g / L is added to the bottom liquid in parallel with a complexing agent solution, a sodium hydroxide solution, and a metal salt solution, the rest is the same as in Example 1.

[0095] The cathode precursor material for a sodium-ion battery obtained by the preparation methods described in the above examples and comparative examples is mixed with sodium carbonate at a grinding ratio of 1:0.45, sintered at 900 °C for 15 h, and then cooled with the furnace to obtain a cathode material for a sodium-ion battery; the obtained cathode material for a sodium-ion battery is made into a cathode sheet, and then a sodium metal sheet is used as the anode, and an NaClO4 solution is used as the electrolyte to assemble a CR2032 button cell. Then, within the voltage range of 2.0 - 4.2 V and under the condition of a current density of 0.1 C, an electrochemical performance test is carried out. The discharge specific capacity of the first cycle and the capacity retention rate after 50 cycles are shown in Table 1.

[0096] Table 1

[0097]

[0098]

[0099] As can be seen from the above table:

[0100] The sodium-ion battery prepared from the cathode precursor material of the present invention has excellent performance. The discharge specific capacity of the first cycle is above 150 mAh / g, and the capacity retention rate after 50 cycles is above 85.44%; from Example 1 and Comparative Example 1, it can be seen that the organic additive in the bottom liquid of the present invention can promote the coprecipitation of metal ions, which is beneficial to preparing a cathode precursor material for a sodium-ion battery with low nickel and high magnesium contents; from Example 1 and Comparative Example 2, it can be seen that after the addition method of the organic additive of the present invention is changed, the crystal nuclei formed at startup cannot obtain the expected size and distribution, which will affect the subsequent reaction and make the final product unable to achieve the technical effect of the present invention; from Example 1 and Examples 4 - 7, it can be seen that the type and addition amount of the organic additive of the present invention will affect the battery performance; from Example 1 and Examples 8 - 11, it can be seen that the use of the combined complexing agent, the ratio of the addition amounts of the two complexing agents, and the type of the complexing agent will affect the battery performance; from the examples and Examples 12 - 13, it can be seen that when two or more complexing agents are used in the present invention, it can promote the precipitation of metal ions and ensure the performance of the material.

[0101] In summary, the present invention provides a cathode precursor material for a sodium-ion battery, a preparation method and an application thereof. By controlling the conditions of the coprecipitation reaction, magnesium element is introduced and the nickel content is reduced, so that the low-nickel precursor material can be synthesized by the coprecipitation method, while ensuring the performance of the precursor, the cost of the cathode material precursor for the sodium-ion battery is further reduced.

[0102] The above is only the specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by any person skilled in the art within the technical scope disclosed by the present invention fall within the protection scope and the disclosure scope of the present invention.

Claims

1. A preparation method of a cathode precursor material for a sodium-ion battery, characterized in that, The preparation method comprises the following steps: Mix a metal salt solution, a complexing agent solution, and a precipitating agent solution into a bottom solution to conduct a coprecipitation reaction to obtain the positive electrode precursor material for the sodium-ion battery; wherein, the bottom solution includes an organic additive, and the metal salt solution includes a nickel salt, a magnesium salt, a manganese salt, and an iron salt; The organic additive includes any one or a combination of at least two of ethanol, ethylene glycol, glycerol, or dipropylene glycol; The complexing agent solution includes more than two different types of complexing agents; In the complexing agent solution, the molar ratio of any two complexing agents is (1-10):(1-10); In the metal salt solution, the molar ratio of nickel ions, iron ions, manganese ions, and magnesium ions is x:y:z:(1-x-y-z), where x is 0.1-0.2, y is 0.10-0.34, and z is 0.34-0.

5.

2. The preparation method according to claim 1, characterized in that, The complexing agent solution includes a combination of at least two of an ammonia water solution, an oxalic acid solution, a sodium oxalate solution, a citric acid solution, a sodium citrate solution, a lactic acid solution, or a tartaric acid solution; 3. The preparation method according to claim 1, characterized in that, The complexing agent solution includes a combination of at least two of a citric acid solution, a lactic acid solution, or a tartaric acid solution; 4. The preparation method according to claim 1, characterized in that, In the complexing agent solution, the concentration of any one complexing agent is 0.01-0.3 mol / L; 5. The preparation method according to claim 1, characterized in that, The organic additive is glycerol and / or dipropylene glycol; 6. The preparation method according to claim 1, wherein The bottom solution further includes water, and the mass ratio of water to the organic additive is (1-10):(0-1), but does not include (1-10):0; 7. The preparation method according to claim 6, characterized in that, The mass ratio of water to the organic additive is (1-10):(0.2-1); 8. The preparation method according to claim 1, wherein The bottom solution further includes sodium hydroxide and ammonia water; 9. The preparation method according to claim 1, characterized in that, The pH of the bottom solution is 10-11.8; 10. The preparation method according to claim 8, characterized in that, In the bottom solution, the concentration of ammonia water is 0.01-0.3 mol / L; 11. According to the preparation method described in claim 1, characterized in that, In the metal salt solution, the total metal ion concentration is 2-4 mol / L; 12. The preparation method according to claim 1, characterized in that, The concentration of the precipitating agent solution is 1-3 mol / L; 13. According to the preparation method described in claim 1, characterized in that, The precipitating agent solution includes a sodium hydroxide solution; 14. The preparation method according to claim 1, characterized in that, The temperature of the coprecipitation reaction is 40-70 °C, the pH is 8.0-11.0, and the time is 50-100 h; 15. The preparation method according to claim 1, wherein, The coprecipitation reaction is carried out in nitrogen; 16. The preparation method according to claim 1, wherein The coprecipitation reaction is carried out under stirring, and the stirring speed is 200-400 r / min; 17. The preparation method according to claim 1, wherein, The preparation method comprises the following steps: Mix a metal salt solution, a complexing agent solution, and a precipitating agent solution into a bottom solution, and conduct a coprecipitation reaction for 50-100 h under a nitrogen atmosphere, a temperature of 40-70 °C, a pH of 8.0-11.0, and a stirring speed of 200-400 r / min to obtain the positive electrode precursor material for the sodium-ion battery; The pH of the bottom solution is 10-11.8, and it includes water, an organic additive, sodium hydroxide, and ammonia water. Among them, the organic additive includes any one or a combination of at least two of ethanol, ethylene glycol, glycerol, or dipropylene glycol. The mass ratio of water to the organic additive is (1-10):(0-1), but does not include (1-10):

0. In the bottom solution, the concentration of ammonia water is 0.01-0.3 mol / L; The complexing agent solution includes a combination of at least two of aqueous ammonia solution, oxalic acid solution, sodium oxalate solution, citric acid solution, sodium citrate solution, lactic acid solution or tartaric acid solution. In the complexing agent solution, the concentration of any one complexing agent is 0.01 - 0.3 mol / L, and the molar ratio of any two complexing agents is (1 - 10):(1 - 10); In the metal salt solution, the molar ratio of nickel ions, iron ions, manganese ions and magnesium ions is x:y:z:(1 - x - y - z), where x is 0.1 - 0.2, y is 0.10 - 0.34, z is 0.34 - 0.5, and the total metal ion concentration is 2 - 4 mol / L.

18. A cathode precursor material for a sodium-ion battery, characterized in that, The sodium-ion battery cathode precursor material is prepared by the preparation method according to any one of claims 1 - 17.

19. A cathode material for a sodium-ion battery, characterized in that, The sodium-ion battery cathode material is prepared from a sodium source and the sodium-ion battery cathode precursor material according to claim 18.

20. A sodium-ion battery, characterized in that, The sodium-ion battery includes the sodium-ion battery cathode material according to claim 19.

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