Preparation method of multi-element precursor and positive electrode material for sodium-ion battery from laterite nickel ore

Abstract

The application provides a preparation method of a sodium-ion battery multi-element precursor and a positive electrode material from laterite nickel ore. The preparation method directly converts the laterite nickel ore into a jarosite precipitate and a nickel solution containing multiple trace metals, and then synthesizes a multi-element high-nickel precursor from the nickel solution through a coprecipitation process. Finally, the jarosite and the precursor are mixed and sintered to prepare the positive electrode material of the sodium-ion battery. The preparation method directly converts the mineral resources into the positive electrode material, greatly shortens the production process, and reduces the production cost, thereby providing a good reference for the preparation of the sodium-ion battery multi-element precursor and the positive electrode material. Meanwhile, the preparation method can control the residual amount of impurity metal elements in the raw materials in a targeted manner, so as to achieve in-situ doping in the preparation process of the precursor. The effective utilization of all metals in the laterite nickel ore is realized, the economic value of the resources is improved, and the raw material loss is reduced. The positive electrode material exhibits excellent electrochemical performance and has a good commercial prospect.

Description

TECHNICAL FIELD

[0001] The application relates to the field of sodium ion battery positive electrode materials, and particularly relates to a bauxite nickel ore preparation method for preparing a sodium ion battery multi-element precursor and a positive electrode material. BACKGROUND

[0002] The rapid commercialization of lithium ion batteries promotes the efficiency of human storage and utilization of clean energy, and is widely applied to the fields of mobile communication and new energy vehicles. Due to the uneven distribution of lithium resources and the rising cost, and the high cost of cobalt resources, sodium ion batteries as the most potential alternative batteries have been rapidly developed, and the development of new-type sodium ion battery positive electrode precursors is particularly important. Sodium ion batteries have the same working principle as lithium ion batteries, but the situation is different in the sodium ion battery system. Due to the large difference in the radius of Ni and Na, there is almost no Ni and Na mixing in the layered oxide, which shows that it is possible to develop high-performance cobalt-free high-nickel sodium ion battery layered oxide positive electrodes.

[0003] Sodium ion batteries have great potential in future large-scale energy storage, portable electronic devices, small and low-speed electric vehicles and other applications due to the global rich and low-cost sodium resources. Layered transition metal oxide positive electrode precursors have become one of the most promising sodium ion battery positive electrode precursors due to the simple preparation process, high specific capacity and high ionic conductivity. However, in all the current positive electrode precursor preparation methods, the raw materials are high-purity nickel sulfate and other nickel salts. From nickel ore to nickel salt preparation, and then to positive electrode precursor preparation, the process is extremely cumbersome. Not only does it increase the cost of synthesizing positive electrode precursors, but it is also not conducive to the promotion of sodium ion batteries.

[0004] The patent discloses a bauxite nickel ore preparation method for preparing a sodium ion battery multi-element precursor and a positive electrode material. The preparation method can directly convert bauxite nickel ore into a sodium ion positive electrode material. The main metal elements nickel and iron in the bauxite nickel ore can be applied to the preparation of the sodium ion battery positive electrode material, which has more application value than lithium ion batteries. Moreover, a small amount of metal impurity elements in the ore can be in-situ doped into the positive electrode precursor, improving the electrochemical performance of the positive electrode material. Moreover, the preparation method can realize directional selective doping of the impurity elements, so that the positive electrode material exhibits good charge-discharge performance, conductivity, structural stability and electrochemical cycle stability in the sodium ion battery, and has good commercialization prospects. At the same time, the preparation method directly converts the ore resources into the positive electrode material, and all the metal elements in the bauxite nickel ore are comprehensively utilized, greatly saving the preparation process, reducing the waste of material circulation transportation and process, improving the material yield, reducing the production cost, and having good reference value for the preparation of the sodium ion battery positive electrode precursor. SUMMARY

[0005] To overcome the shortcomings of existing technologies, this invention provides a method for preparing sodium-ion battery multi-component precursors and cathode materials from laterite nickel ore. This method omits cumbersome process systems and simplifies the process flow from raw materials directly to cathode precursors. The sodium-ion battery cathode material prepared by this method achieves several advantages. First, sodium sulfate is used to obtain sodium ferroalloy, which is directly applied to the cathode material preparation, significantly shortening the process flow, reducing raw material loss, and facilitating industrialization. Second, the sodium-ion battery cathode synthesized from the precursor exhibits stable structure and performance, with electrochemical performance comparable to commercially available cathode materials. Furthermore, the in-situ doping of trace impurity metals such as manganese, aluminum, and chromium in the laterite nickel ore into the precursor during preparation further enhances the cathode performance.

[0006] The technical solution adopted by this invention to solve its technical problem is a sodium-ion battery material prepared from laterite nickel ore, wherein the sodium-ion battery material includes one or more of a multi-component precursor and a cathode material, wherein...

[0007] The positive electrode precursor is a nickel-magnesium base layer hydroxide with the chemical formula Ni. x Mg y (OH)₂, where 0.5≤x≤1, 0≤y≤0.5, x+y=1; the positive electrode material is a nickel-iron-magnesium layered oxide with the chemical formula Na. m Ni x Fe y Mg z O2, where 0.5≤m≤1, 0.5≤x<1, 0.4≤x≤0.5, 0≤z≤0.2, x+y+z=1, and M is one or more of Mn, Al, and Cr.

[0008] This invention also provides a method for preparing sodium-ion battery materials using laterite nickel ore, comprising two steps: processing the laterite nickel ore and preparing the battery materials, namely:

[0009] (1) The laterite nickel ore is crushed and screened, and the obtained laterite nickel ore powder is added to a certain amount of acid solution. The mixture is continuously stirred at a certain temperature for leaching, and the leachate is obtained by filtration.

[0010] (2) Add a small amount of H2O2 solution to the leachate from step (1) and heat it. Then add sodium sulfate and stir continuously to control the pH to obtain sodium ferric sulfate precipitate, and filter it.

[0011] (3) The iron-removing leachate obtained by filtering in step (2) is selectively purified under a specific impurity removal agent to obtain a nickel-magnesium solution in which specific impurity elements are retained.

[0012] (4) adding the nickel-magnesium solution, a certain concentration of the precipitant NaOH solution and the complexing agent NH3·H2O solution obtained in step (3) into a reactor, and performing a co-precipitation reaction while continuously stirring, to obtain a positive electrode precursor of a battery material.

[0013] Preferably, the particle size of the laterite nickel ore powder in step (1) is 1 μm-100 μm.

[0014] Preferably, the acid used in step (1) is one or more of hydrochloric acid and sulfuric acid, the ratio of the acid to the laterite nickel ore powder is 1-5:1 by mass, the leaching temperature is 70-150°C, and the leaching time is 3-10 h.

[0015] Preferably, in step (2), the iron precipitation temperature is 70-100°C, and the pH is 1.0-3.5; in step (3), the impurity removal agent is one or more of sodium carbonate, sodium phosphate and phosphoric acid, and the metal concentration of the obtained nickel-magnesium solution is 100-150 g / L.

[0016] Preferably, in step (4), the concentration of the precipitant NaOH solution is 4-12 mol / L, the concentration of the complexing agent NH3·H2O solution is 2-8 mol / L; the stirring speed of the co-precipitation reaction is 300-850 rpm, the pH of the reaction solution is 10.5-13.5, the ammonia value is 6-13 g / L, the reaction temperature is 60-85°C, the atmosphere in the reactor is controlled to be 0.1%-5.0% oxygen, 95%-99.9% nitrogen or argon, and the reaction time is 24-48 h.

[0017] Preferably, the method further comprises preparing a positive electrode material using the obtained precursor, which comprises: uniformly mixing the precursor with the sodium jarosite precipitate and a supplementary sodium source obtained in step (2) by ball milling, and performing high-temperature sintering, to obtain a sodium-ion battery nickel-iron-magnesium-based multi-element positive electrode material.

[0018] Preferably, the supplementary sodium source is one or more of sodium carbonate, sodium bicarbonate and sodium hydroxide.

[0019] Preferably, the high-temperature sintering comprises: a first-stage calcination at a temperature of 450-600°C for 4-8 h; and a second-stage calcination at a temperature of 700-1000°C for 9-16 h, wherein the calcination atmosphere is one or more of air and pure oxygen; and the heating rate is 2-5°C / min.

[0020] Compared with the prior art, the method has the following beneficial effects:

[0021] (1) The method of the present application processes laterite nickel ore, combines multiple processes such as precursor and positive electrode preparation, realizes the simplification of the positive electrode precursor preparation process, and the production process is simple, which omits the complicated process system and completes the simple process flow from raw material to positive electrode. The method reduces the turnover transportation of intermediate materials and the waste of the process, improves the material yield, reduces the production cost, can significantly reduce the industrial cost, can improve the overall safety of the process, brings greater economic benefits, provides a new idea and guidance for the industrialized production of sodium ion battery precursors and positive electrodes.

[0022] (2) The method of the present application directly obtains the raw material yellow sodium iron alum of the sodium ion battery positive electrode material from the laterite nickel ore, and the main metal element nickel in the processed laterite nickel ore can be directly applied to the positive electrode precursor of the sodium ion battery. Moreover, a small amount of metal impurity elements in the ore can be doped into the positive electrode precursor to improve the electrochemical performance of the material, which will reduce the complicated impurity removal and purification process in the smelting process, reduce environmental pollution, and save resources.

[0023] (3) The precursor prepared by the method of the present application exhibits consistent electrochemical performance with the currently commercialized positive electrode material in the sodium ion battery test after the synthesis of the positive electrode material, and even the in-situ doped positive electrode material has better performance in the preparation process, which has good commercialization prospects. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 is the process flow diagram of the sodium ion battery positive electrode precursor prepared in Example 1 of the present application;

[0025] Figure 2 is the SEM diagram of the sodium ion battery positive electrode precursor prepared in Example 1 of the present application. DETAILED DESCRIPTION

[0026] The present application will be further described below in combination with examples and drawings. The laterite nickel ore used in the present application has the following raw material element content table:

[0027] Raw material element content table

[0028]

[0029] Example 1

[0030] The chemical formula of the sodium ion battery nickel-iron-magnesium-based multi-element positive electrode material of the present example is NaNi 1 / 3 Fe 1 / 3 Mg 1 / 3 O2&Mn.

[0031] The preparation method of the sodium ion battery nickel-iron-magnesium-based multi-element positive electrode material of the present example comprises the following steps:

[0032] (1) The laterite nickel ore is crushed and sieved to obtain laterite nickel ore powder of about 20 μm, and then hydrochloric acid leaching is carried out at an acid-ore ratio of 2.8:1, a leaching temperature of 90°C and a leaching time of 8 h, and then the filtrate is obtained by filtration.

[0033] (2) The leaching solution in step (1) is added with a small amount of H2O2 solution and heated to 85°C, and then 40 g / L of sodium sulfate solution is added and stirred constantly to maintain a pH of 2.5, and a yellow sodium jarosite precipitate is obtained after reaction for 4 h, and the precipitate is filtered; the obtained iron-removing leaching solution is added with 20 g / L of sodium carbonate to maintain a pH of 2.0, and Al, Cr and a large amount of Mg are selectively removed after reaction for 4 h, and a nickel-manganese solution with Ni:Mg = 1:1 is obtained.

[0034] (3) 98.9 g / L of the nickel-manganese solution is added with 6 mol / L of a precipitant NaOH solution and 8 mol / L of a complexing agent NH3·H2O solution into a reaction kettle, and co-precipitation reaction is carried out with constant stirring, the stirring speed in the nucleation period is controlled to be 300 rpm, the pH value of the reaction solution is 12.5, the ammonia value is 8 g / L, the reaction temperature is 65°C, the atmosphere in the reaction kettle is controlled to be 0.8% oxygen and 99.2% nitrogen, and the reaction time is 10 h, and then the solid-liquid mixed slurry is obtained, and the slurry is subjected to washing, filtration, drying and demagnetization, and a sodium-ion battery nickel-based ternary precursor Ni 1 / 2 Mg 1 / 2 (OH)2 is obtained.

[0035] (4) The yellow sodium jarosite obtained in step (2) and the obtained precursor Ni 1 / 2 Mg 1 / 2 (OH)2 are weighed according to a molar ratio Na:TM = 1.05:1, and uniformly mixed, and then subjected to step-by-step high-temperature sintering, calcination at 450°C for 5 h in an air atmosphere, calcination at 750°C for 12 h after temperature rising, and natural cooling, and a sodium-ion battery nickel-iron-manganese-based multi-element positive electrode material NaNi 1 / 3Fe 1 / 3 Mg 1 / 3 O2&Mn is obtained.

[0036] The product of the present embodiment is scanned by a scanning electron microscope, and the precursor result is as shown in Figure 2 .

[0037] A positive electrode made of the sodium-ion battery nickel-iron-manganese-based multi-element positive electrode material for filling conductive material of the present embodiment is assembled into a button cell, and electrochemical performance test is carried out, and the first discharge specific capacity is 142.7 mAh / g at a rate of 0.1C (1C = 180 mA / g) in a voltage range of 3-4.3 V at 25°C, the discharge specific capacity is 128.9 mAh / g at 1C, and the capacity retention rate is 88.3% after 100 cycles.

[0038] Example 2

[0039] The chemical formula of the sodium-ion battery nickel-iron-magnesium-based multi-element positive electrode material of the present example is NaNi 1 / 3 Fe 1 / 3 Mg 1 / 3 O2&Al.

[0040] The preparation method of the sodium-ion battery nickel-iron-magnesium-based multi-element positive electrode material of the present example comprises the following steps:

[0041] (1) Crush and sieve the laterite nickel ore to obtain laterite nickel ore powder of about 18 μm, and then perform hydrochloric acid leaching according to an acid-ore ratio of 2.5:1, a leaching temperature of 85°C, and a leaching time of 10 h, and then filter to obtain a filtrate.

[0042] (2) Add a small amount of H2O2 solution to the leaching solution in step (1) and heat to 90°C, then continuously stir by adding 35 g / L sodium sulfate solution to maintain a pH of 2.8, and react for 6 hours to obtain a jarosite precipitate, which is filtered; the iron-removing leaching solution obtained by filtration is added to 15 g / L phosphoric acid to maintain a pH of 2.6, and reacted for 5 hours to selectively remove Mg, Mn, and Cr, thereby obtaining a nickel-magnesium solution containing Al.

[0043] (6) Add 120.8 g / L of the nickel-magnesium solution, 2 mol / L of the precipitant NaOH solution, and 2 mol / L of the complexing agent NH3·H2O solution into a reaction kettle to perform co-precipitation reaction, continuously stir, control the stirring speed of the nucleation period to be 300 rpm, the pH value of the reaction solution to be 11.8, the ammonia value to be 7.4 g / L, the reaction temperature to be 75°C, control the atmosphere in the reaction kettle to be 0.3% oxygen and 99.7% nitrogen, and the reaction time to be 15 h, to obtain a solid-liquid mixed slurry, which is subjected to washing, filtration, drying, demagnetization, and other operation steps to obtain the sodium-ion battery nickel-based ternary precursor Ni 1 / 2 Mg 1 / 2 (OH)2.

[0044] (4) Weigh a certain proportion of jarosite and sodium hydroxide according to the molar ratio Na:TM=1.03:1, mix the obtained precursor Ni 1 / 2 Mg 1 / 2 (OH)2 uniformly, perform step-by-step high-temperature sintering, first calcine at 400°C for 4 h in an air atmosphere, then heat to 850°C for 16 h, and finally naturally cool, to obtain the sodium-ion battery nickel-iron-magnesium-based multi-element positive electrode material NaNi 1 / 3 Fe 1 / 3 Mg 1 / 3 O2&Al.

[0045] The positive electrode assembled by the positive electrode of the sodium ion battery nickel iron magnesium-based multi-element positive electrode material filled with conductive material is used to assemble a button cell, and electrochemical performance test is carried out. The initial discharge specific capacity of the button cell is 141.5 mAh / g at 0.1C (1C=180 mA / g) rate in the voltage range of 3-4.3 V at 25°C, the discharge specific capacity is 128.3 mAh / g at 1C, and the capacity retention rate is 91.7% after 100 cycles.

[0046] Example 3

[0047] The chemical formula of the sodium ion battery nickel iron magnesium-based multi-element positive electrode material of the present example is Na 0.67 Ni 0.6 Fe 0.2 Mg 0.2 O2&Cr.

[0048] The preparation method of the sodium ion battery nickel iron magnesium-based multi-element positive electrode material of the present example comprises the following steps:

[0049] (1) The laterite nickel ore is crushed and sieved to obtain laterite nickel ore powder with a particle size of about 10 μm. Then, hydrochloric acid leaching is carried out according to an acid-ore ratio of 3.0:1, a leaching temperature of 90°C, and a leaching time of 5 h. Then, the filtrate is obtained by filtration.

[0050] (2) A small amount of H2O2 solution is added to the leaching solution in step (1) and heated to 85°C. Then, 20 g / L of sodium sulfate solution is added and stirred constantly to maintain a pH of 2.5. The reaction is carried out for 4 hours to obtain a jarosite precipitate, which is filtered. The obtained iron-removed leaching solution is added with 25 g / L of sodium carbonate and 20 g / L of phosphoric acid to maintain a pH of 3.2. The reaction is carried out for 5 hours to selectively remove Al and Mn, and a magnesium-nickel solution containing a small amount of chromium is obtained.

[0051] (1) 110.4 g / L of the nickel-magnesium solution, 4 mol / L of the precipitant NaOH solution, and 6 mol / L of the complexing agent NH3·H2O solution are added into a reaction kettle to carry out co-precipitation reaction, and the stirring speed is controlled to be 600 rpm in the nucleation period, the pH value of the reaction solution is 11.2, the ammonia value is 10 g / L, the reaction temperature is 80°C, the atmosphere in the reaction kettle is controlled to be 2.1% oxygen and 97.9% nitrogen, and the reaction time is 20 h. The solid-liquid mixed slurry is washed, filtered, dried, and subjected to magnetic removal and other operation steps to obtain the sodium ion battery nickel-based ternary precursor Ni 0.75 Mg 0.25 (OH)2.

[0052] (3) A certain proportion of jarosite is weighed according to the molar ratio Na:TM=1.10:1, and the obtained precursor Ni 0.75 Mg 0.25The sodium ion battery nickel-iron-magnesium-based multi-element positive electrode material is prepared by uniformly mixing (OH)2, and performing staged high-temperature sintering, i.e., calcining at 500 DEG C for 6 hours in an air atmosphere, then calcining at 900 DEG C for 12 hours, and finally naturally cooling, to obtain the sodium ion battery nickel-iron-magnesium-based multi-element positive electrode material Na 0.67 Ni 0.6 Fe 0.2 Mg 0.2 O2&Cr.

[0053] The positive electrode assembled by the positive electrode of the sodium ion battery nickel-iron-magnesium-based multi-element positive electrode material filled with the conductive material is used to assemble a button cell, and electrochemical performance test is performed. The first discharge specific capacity of the button cell is 165.8 mAh / g at 0.1C (1C=180 mA / g) rate in the voltage range of 3-4.3 V at 25 DEG C, the discharge specific capacity is 139.7 mAh / g at 1C, and the capacity retention rate is 89.9% after 100 cycles.

[0054] Example 4

[0055] The chemical formula of the sodium ion battery nickel-iron-magnesium-based multi-element positive electrode material of the example is NaNi 0.8 Fe 0.15 Mg 0.05 O2&Cr / Mn.

[0056] The preparation method of the sodium ion battery nickel-iron-magnesium-based multi-element positive electrode material of the example comprises the following steps:

[0057] (1) The laterite nickel ore is crushed and sieved to obtain laterite nickel ore powder with a particle size of about 25 μm. Then, hydrochloric acid leaching is performed according to an acid-ore ratio of 3.5:1, a leaching temperature of 70 DEG C, and a leaching time of 10 hours. Then, the filtrate is obtained by filtration.

[0058] (2) A small amount of H2O2 solution is added to the leaching solution in step (1) and heated to 100 DEG C. Then, 20 g / L of sodium sulfate solution is added and stirred constantly to maintain a pH of 3.1. The reaction is performed for 6 hours to obtain a jarosite precipitate, which is filtered. The iron-removed leaching solution obtained by filtration is added with 20 g / L of sodium carbonate to maintain a pH of 2.8. The reaction is performed for 6 hours to selectively remove Al and Mg, and a nickel-magnesium solution containing Mn and Cr is obtained.

[0059] (1) 120.6 g / L of a nickel-magnesium solution, 3 mol / L of a precipitant NaOH solution, and 3 mol / L of a complexing agent NH3·H2O solution were added into a reaction kettle to perform a co-precipitation reaction, and stirring was continuously performed, the stirring speed in the nucleation stage was controlled to be 480 rpm, the pH value of the reaction solution was 11.8, the ammonia value was 7.6 g / L, the reaction temperature was 70°C, the atmosphere in the reaction kettle was controlled to be 1.0% oxygen and 99.0% nitrogen, the reaction time was 24 h, and then a solid-liquid mixed slurry was obtained. The slurry was subjected to a washing, filtration, drying, and magnetic removal operation step to obtain a sodium-ion battery nickel-based ternary precursor Ni 0.95 Mg 0.05 (OH)2.

[0060] (3) A certain proportion of the yellow sodium jarosite, sodium bicarbonate, and the obtained precursor Ni 0.95 Mg 0.05 (OH)2 were weighed according to the molar ratio Na:TM = 1.03:1, uniformly mixed, and subjected to a step-by-step high-temperature sintering, calcined at 550°C for 4 h in an air atmosphere, then calcined at 950°C for 14 h, and finally naturally cooled to obtain a sodium-ion battery nickel-iron-magnesium-based multi-element positive electrode material NaNi 0.8 Fe 0.15 Mg 0.05 O2&Cr / Mn.

[0061] The positive electrode assembled from the sodium-ion battery nickel-iron-magnesium-based multi-element positive electrode material used for filling the conductive material in the example was assembled into a button cell, and electrochemical performance testing was performed. The first discharge specific capacity was 181.3 mAh / g at 0.1C (1C = 180 mA / g) rate under a voltage of 3-4.3 V at 25°C, the discharge specific capacity was 163.6 mAh / g at 1C, and the capacity retention rate was 90.4% after 100 cycles.

[0062] Impurity removal solution content table

[0063] g / L Ni Fe Mg Mn Al Cr Example 1 70.63 / 30.25 0.34 / / Example 2 85.17 / 35.35 / 0.69 / Example 3 96.79 / 13.29 / / 0.47 Example 4 118.74 / 3.06 0.28 / 0.54

[0064] Acid leaching solution element content table

[0065] Element Example 1 Example 2 Example 3 Example 4 Ni 99.8％ 99.8％ 99.8％ 99.8％ Fe 99.1％ 98.5％ 99.5％ 99.3％ Mn 92.7％ 91.5％ 93.1％ 92.9％ Mg 99.5％ 99.1％ 99.7％ 99.5％ Al 91.1％ 90.4％ 92.7％ 92.0％ Zn 93.9％ 91.7％ 95.4％ 94.2％ Cr 87.9％ 85.4％ 89.3％ 88.9％

[0066] Iron precipitation rate table of leaching solution

[0067] Item Example 1 Example 2 Example 3 Example 4 Ferrous sink rate 100％ 100％ 100％ 100％

[0068] Comparative Example 1

[0069] The sodium-ion battery nickel-iron-magnesium-based positive electrode material used in the present comparative example was a commonly sold positive electrode material on the market, and its chemical formula was NaNi 1 / 3 Fe 1 / 3 Mg 1 / 3O2.

[0070] The positive electrode material of the present comparative example was assembled into a positive electrode to form a button cell, and electrochemical performance test was conducted. The initial discharge gram capacity at 0.1 C (1 C = 180 mA / g) rate in the voltage range of 3-4.3 V at 25°C reached 138.5 mAh / g, the discharge specific capacity at 1 C was 122.4 mAh / g, and the capacity retention rate after 100 cycles reached 71.2%.

[0071] Comparative Example 2

[0072] The present comparative example used a conventional yellow sodium jarosite material sold on the market, and the precursor prepared in Example 1 was combined to form NaNi 1 / 3 Fe 1 / 3 Mg 1 / 3 O2&Mn.

[0073] The positive electrode material of the present comparative example was assembled into a positive electrode to form a button cell, and electrochemical performance test was conducted. The initial discharge gram capacity at 0.1 C (1 C = 180 mA / g) rate in the voltage range of 3-4.3 V at 25°C reached 138.5 mAh / g, the discharge specific capacity at 1 C was 122.4 mAh / g, and the capacity retention rate after 100 cycles reached 71.2%.

[0074] Electrochemical performance table of positive electrode material

[0075]

Claims

1. A method for preparing sodium-ion battery materials from laterite nickel ore, characterized by: The process of processing laterite nickel ore and preparation of battery material includes two steps, namely: (1) crushing and screening the laterite nickel ore, adding a certain amount of acid solution to the obtained laterite nickel ore powder, continuously stirring at a certain temperature for leaching, and filtering to obtain a leaching solution; (2) adding a small amount of H2O2 solution to the leaching solution in step (1) and heating, then adding sodium sulfate and continuously stirring to control the pH to obtain a jarosite precipitate, and filtering; (3) selectively removing impurities from the iron-removed leaching solution obtained by filtering in step (2) under a specific impurity removal agent to obtain a nickel-magnesium solution with specific impurity elements retained; (4) adding the nickel-magnesium solution in step (3), a certain concentration of precipitant NaOH solution and complexing agent NH3·H2O solution into a reaction kettle, carrying out co-precipitation reaction, and continuously stirring to obtain a positive electrode precursor of battery material after a period of reaction. In step (2), the iron precipitation temperature is 70-100℃, and the pH is 1.0-3.

5. In step (3), the impurity removal agent is one or more of sodium carbonate, sodium phosphate and phosphoric acid, and directional impurity removal is achieved by adding an appropriate amount and adjusting the pH due to the different precipitation equilibrium constants. The obtained nickel-magnesium solution has a metal concentration of 100-150g / L. In step (4), the concentration of the precipitant NaOH solution is 4-12mol / L, and the concentration of the complexing agent NH3·H2O solution is 2-8mol / L. The stirring speed of the co-precipitation reaction is 300-850rpm, the pH of the reaction solution is 10.5-13.5, the ammonia value is 6-13g / L, the reaction temperature is 60-85℃, the atmosphere in the reaction kettle is controlled to be 0.1%-5.0% oxygen, 95%-99.9% nitrogen or argon, and the reaction time is 24-48h.

2. The method of preparing sodium-ion battery materials from red mud according to claim 1, characterized in that: In step (1), the particle size of the laterite nickel ore powder is 1μm-100μm.

3. The method of preparing sodium-ion battery materials from red mud according to claim 1, characterized in that: In step (1), the leaching acid is one or more of hydrochloric acid and sulfuric acid, the ratio of acid to laterite nickel ore powder is 1-5:1 by mass, the leaching temperature is 70-150℃, and the leaching time is 3-10h.

4. The method of preparing sodium-ion battery materials from red mud according to any one of claims 1 to 3, characterised in that: It also includes using the obtained precursor to prepare a positive electrode material, which includes, ball-milling the precursor with the jarosite precipitate in step (2) and a supplementary sodium source to obtain a sodium-ion battery nickel-iron-magnesium-based multi-element positive electrode material by high-temperature sintering.

5. The method of preparing sodium-ion battery materials from red mud according to claim 4, characterized in that: The supplementary sodium source is one or more of sodium carbonate, sodium bicarbonate and sodium hydroxide.

6. The method of preparing sodium-ion battery materials from red mud according to claim 4, characterized in that: The high-temperature sintering includes a first stage of calcination at a temperature of 450-600℃ for 4-8h, and a second stage of calcination at a temperature of 700-1000℃ for 9-16h, and the calcination atmosphere is one or more of air and pure oxygen, and the heating rate is 2-5℃ / min.

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