A quaternary precursor material and its preparation method and application

Abstract

The present invention discloses a quaternary precursor material and its preparation method and application, the method comprising subjecting nanometal to acid-carbonization treatment to obtain a metal core, mixing an alkali solution, a metal salt mixture, a doping salt solution, and a complexing agent solution to form a mixed reaction solution, adding the metal core to the mixed reaction solution for precipitation reaction, and preparing a quaternary precursor material, which is sintered and broken at high temperature to obtain a positive electrode quaternary material. The application of this quaternary material to the positive electrode of a sodium ion battery can improve battery performance. The positive electrode material prepared by the quaternary material precursor provided by the present invention has high tap density, good electronic conductivity, and high energy density. The preparation method provided by the present invention adds part of the metal core at the beginning of the reaction to stabilize the initial reaction; continuously adding the metal core during the reaction alleviates the effects of pH, ammonia value, etc. on particle growth; the multi-point feeding method makes the precipitation reaction rate uniform, thereby improving material performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of sodium ion batteries, and in particular relates to a quaternary precursor material and a preparation method and application thereof. Background Art

[0002] Sodium-ion batteries are secondary batteries that rely on the movement of sodium ions between positive and negative electrodes to complete charging and discharging. Their operating principle is similar to that of the widely used lithium-ion battery. Amidst bottlenecks in lithium resource supply and rising lithium-ion battery prices, sodium-ion batteries are gaining popularity due to their clean and environmentally friendly nature, abundant and widely available raw materials, low cost, enhanced safety, and excellent high- and low-temperature performance. They hold broad application prospects in power batteries and large-scale energy storage.

[0003] In sodium-ion batteries, ternary layered oxides are still the most widely used cathode materials. However, traditional ternary materials undergo phase transitions during battery charge and discharge cycles, causing their structures to be destroyed and significantly reducing battery capacity.

[0004] With the deepening of research, it was found that the addition of specific elements can improve the original structure and significantly improve the electrochemical properties of the material. A large number of experiments have shown that the addition of non-ferrous metals such as Cu, Zr, Zn, Ti, Mg, Al, Y, La, and W during the wet synthesis of the original Fe-based precursor can significantly improve the material's capacity, cycle, rate, safety and other performance. With the deepening of research, quaternary precursor materials came into being. Fe-based Cu quaternary precursor materials, Fe-based Zn quaternary precursor materials, Fe-based Mg quaternary precursor materials, etc. have completed experimental breakthroughs and are gradually moving towards the mass production stage.

[0005] Chinese invention patent CN115594233A discloses a sodium-ion battery quaternary positive electrode material precursor, its preparation method and application, and further discloses a method for preparing the positive electrode material precursor: providing a first mixed salt solution and a second mixed salt solution, the first mixed salt solution containing a soluble nickel salt and a manganese salt, the second mixed salt solution containing a chelating agent, a soluble ferrous salt and a magnesium salt, independently and continuously introducing the first mixed salt solution and the second mixed salt solution, and continuously introducing an ammonia solution and a pH regulator solution, co-precipitation reaction, and obtaining a quaternary positive electrode material precursor. However, the preparation process provided by this invention has great limitations. For metals with strong amphoteric properties, it is impossible to completely precipitate. In addition, the initial nucleation control is difficult, and the primary particles of the internal structure vary greatly. Chinese invention patent CN108987711A discloses a spherical sodium ion battery positive electrode quaternary precursor material and its preparation method, and further discloses a method for preparing a positive electrode material precursor: manganese salt, nickel salt, copper salt and magnesium salt are prepared into a mixed salt solution according to a set ratio, ethylene glycol and urea are added, and after sufficient dissolution, a precipitate is obtained by hydrothermal reaction, and the precipitate is washed and dried to obtain a solid powder; the disadvantages of this invention are: 1. It adopts a hydrothermal method for one-time synthesis, uses organic matter and urea as the precipitation environment, the process evaporates too quickly, the system changes greatly, and the control is difficult; 2. The production capacity is low and the scale-up is difficult; 3. The safety of the high-pressure environment is poor; Chinese invention patent CN115974174A Disclosed are a sodium ion nickel manganese magnesium iron quaternary positive electrode material and a preparation method thereof. A preferred preparation method of the positive electrode material precursor comprises the following steps: dissolving PAN and PMMA in N,N-dimethylformamide to obtain a PAN-PMMA viscous solution; then dissolving sodium salt, nickel salt, manganese salt, magnesium salt and iron salt into the prepared PAN-PMMA viscous solution to prepare a spinning solution; pouring the spinning solution into a syringe; and controlling the propulsion speed of the spinning solution by using a syringe pump; using copper foil as a collector on a drum; applying a positive high voltage between a needle and a receiving copper foil to stimulate spinning; and connecting the copper foil to a negative high voltage to collect the spun fibers; collecting the fibers on the copper foil after continuous spinning to obtain a white fiber film; and performing a fiber stabilization treatment at a low temperature to obtain Na x Ni y Mn z Mg 0.9-y-z Fe 0.1 O2; The disadvantages of this invention are: 1. The process control is difficult; 2. The material has an unconventional morphology and a narrow range of applications.

[0006] Therefore, there is an urgent need to provide a preparation method that can improve the tap density of the quaternary precursor material, reduce the residual alkali of the material, improve the internal structure of the material, reduce the difficulty of synthesis, and increase the electronic conductivity of the material, thereby improving the electrical properties of the material, while taking into account the easy promotion and operability of the preparation method. Summary of the Invention

[0007] The present invention provides a quaternary precursor material and its preparation method and application, aiming to solve the problems in the prior art of preparing quaternary precursor materials for nano-ion batteries, such as cumbersome and complicated preparation methods and poor electrochemical performance of the prepared materials.

[0008] In order to achieve the above technical effects, the technical solutions adopted by the present invention are as follows:

[0009] The present invention provides a method for preparing a quaternary precursor material, comprising the steps of carbonizing a nanometal to obtain a carbide metal core; mixing an alkali solution, a metal salt mixture, a doping salt solution, and a complexing agent solution to form a mixed reaction solution; and adding the carbide metal core to the mixed reaction solution to carry out a precipitation reaction to obtain the quaternary precursor material.

[0010] Furthermore, the preparation method includes subjecting the nanometal to acid treatment and carbonization treatment to obtain a carbide metal core; mixing an alkali solution, a metal salt mixture, a doping salt solution, and a complexing agent solution to form a mixed reaction solution; while forming the mixed reaction solution, adding the carbide metal core to perform a precipitation reaction, and after the reaction is completed, adding an alkaline chloride composite salt for washing and then performing post-treatment to obtain the quaternary precursor material.

[0011] The original core, i.e., the nano-scale metal core after acid treatment and carbonization treatment, is continuously added during the preparation process, which effectively buffers the influence of pH and ammonia value parameter fluctuations on particle growth. The chlorinated alkaline salt washing process is adopted. On the one hand, hydroxide replaces sulfate in the crystal lattice, which can significantly reduce the sulfur content. The residual chloride ions have strong oxidizing properties, and the surface potential is further enhanced, which effectively prevents the carbon dioxide in the air from reacting with the residual moisture in the particles to form residual alkali. The reaction of generating residual alkali is the process of enhancing the particle potential. The increase of chloride ions makes the material have a higher ionic potential, which makes the original residual alkali reaction equilibrium shift to the left, thereby reducing the generation of residual alkali.

[0012] A metal core is formed in the material, the amorphous area inside the particles is reduced, the material is more compact, and the energy density is increased.

[0013] The carbonized metal core makes the initial growth process smoother while improving the electronic conductivity of the material and the rate performance.

[0014] Specifically, the preparation method comprises the following steps:

[0015] S1: Metal nucleic acidization treatment: Weigh a certain amount of metal and use ultra-speed nano-grinding to grind the metal particles to nanoscale. After grinding, add a certain concentration of oxidizing acid, stir for a certain period of time, then take it out, wash it with water, and dry it for later use.

[0016] S2: Carbonization treatment of metal core: add a certain amount of carbon powder to the organic solvent, add thickener and binder to adjust to a certain viscosity, then place the metal core dried in S1 into the above solution, stir at low speed for a period of time, and then take out and dry.

[0017] S3: Preparation before reaction: prepare alkali solution, metal salt mixture, doping salt solution, and complexing agent solution respectively, add base liquid into the reaction vessel, add carbonized metal core, and add alkali solution to adjust pH, start stirring and nitrogen, and start heating.

[0018] S4: Precipitation reaction: Add metal salt mixture, doping salt solution, alkali solution, and complexing agent solution into the reactor in proportion, add carbonized metal cores at regular intervals and in fixed quantities, control system pH value, stirring, oxygen content, ammonia concentration and other parameters, and stop feeding when the particle size reaches the required level.

[0019] S5: Alkaline chloride compound salt washing: add a certain amount of alkaline chloride compound salt prepared by alkali + acid to the precipitated material, stir for a certain time after adding, wash the material with water after stirring, and dry it for use after washing.

[0020] Furthermore, the metal is one or more non-ferrous metals such as Cu, Zr, Zn, Ti, Mg, Al, Y, La, and W.

[0021] Furthermore, the ultra-speed grinding process in S1 is as follows: the grinding speed is 3000 rpm, the grinding medium is zirconia balls, the zirconia balls are 10-20 μm, and the grinding time is determined by the output particle size, generally 2-6 hours.

[0022] Furthermore, in S1, the nanometal cores are ground to a particle size D50 of 10-200 nm.

[0023] Furthermore, the oxidizing acid is one or more of nitric acid, chloric acid, perchloric acid, and concentrated sulfuric acid.

[0024] Furthermore, the organic solvent in S2 includes any one of anhydrous ethanol, triethanolamine, and styrene.

[0025] Furthermore, the molar ratio of the oxidizing acid to the metal in S1 is acid:metal=1:10-100 (the main purpose is to modify the surface into a rough structure, and the content of the oxidizing acid can cover all metal surfaces and corrode to a certain depth, so the added amount is not high).

[0026] Furthermore, the stirring speed during the acidification process is 200-600 rpm, and the stirring time is 0.8 h (the stirring time cannot be too long, otherwise the surface reaction will be sufficient and a smooth structure will be easily formed. The purpose of acidification is to form a rough surface of the metal particles, increase the surface binding energy, and prepare for subsequent treatment).

[0027] Furthermore, the water washing process in S1 is: using warm water at a temperature of 60-80° C., a water to material ratio of water: material = 1:0.6, a washing time of 0.3-2 hours, and filtering the water after washing is completed.

[0028] Furthermore, the drying process in S1 is: temperature 150-300° C., drying time 6-36 hours (to fully dry the surface moisture).

[0029] Furthermore, the thickener is an acrylic thickener.

[0030] Furthermore, the adhesive is a conductive adhesive prepared by mixing toughened epoxy resin, silver powder, 4-methylimidazole, and solvent in a mass ratio of 95-95:3:2:56, wherein the solvent is a low-boiling point organic alcohol, including ethylene glycol or isopropyl alcohol.

[0031] Furthermore, the amounts of carbon powder, thickener and binder added to S2 are carbon powder: thickener: binder = 90-95: 2-5: 3-5, and the solid content after mixing is 40-60%.

[0032] Furthermore, the viscosity of the mixed solution is 2000-6000 mPa·s.

[0033] Furthermore, the amount of metal core added to S2 is 3000-50000 ppm.

[0034] Furthermore, the low-speed stirring rate in S2 is 50-200 rpm, and the stirring time is 0.5-4 h.

[0035] Furthermore, the drying process in S2 is: temperature 60°C, drying time 24h (low temperature and slow baking, reasons: 1. Avoid the surface carbon layer structure from falling off due to too fast dehydration rate, 2. Avoid high temperature damage to the structure of the adhesive and reduce the bonding effect).

[0036] Furthermore, the metal salt mixture in S3 is a ternary mixed salt solution, and the metal salt ratio is Ni:Fe:Mn=0.1-0.8:0.1-0.8:0.1-0.8.

[0037] Furthermore, the doping salt solution is the salt solution of the metal added in S1.

[0038] Furthermore, the alkali solution includes any one of potassium hydroxide and sodium hydroxide solution or a combination of the two; and the complexing agent solution includes an ammonia solution.

[0039] Furthermore, the concentration of the alkali solution in S3 is 4-10 mol / L, the concentration of the metal salt is 2-8 mol / L, the concentration of the doping salt is 2-8 mol / L, and the concentration of the complexing agent is 3-12 mol / L.

[0040] Furthermore, 0.5-10 mol / L of metal cores are added to S3; (the amount added is calculated based on the concentration of the metal element after 2 hours of normal blank feeding. The specific amount added needs to match the actual feeding rate).

[0041] Furthermore, the bottom solution in S3 includes a non-salted water, an alkali solution is added to adjust the pH to 9-12, the solution is stirred at 300-900 rpm, and the temperature is raised to 50-80° C. at a rate of 2° C. / min.

[0042] Furthermore, in S4, the metal salt mixture, doping salt solution, alkali solution, and complexing agent solution are added in a molar ratio of metal salt: doping salt: alkali solution: complexing agent = 1:1:0.2-0.8:0.2-0.6.

[0043] Furthermore, four tubes of doped salt enter the reactor respectively, and the tubes are two short and two long and symmetrically distributed.

[0044] Furthermore, the amount of metal cores added per hour in S4 is 0.05-0.5 of the total feed molar amount per hour, and is added every hour; (the reasons for continuous addition during the process: 1. to consume the excessive primary particles generated in the process, 2. to avoid the phenomenon of rapid particle growth in the early stage due to early stage or parameter abnormalities).

[0045] Furthermore, the pH of the precipitation reaction process in S4 is 9-12, the stirring is carried out at a speed of 400-900 rpm, the oxygen content is less than 5%, and the ammonia concentration is 2-8 g / L.

[0046] Furthermore, when the particle size reaches 3-15 μm, no further feeding is required.

[0047] Furthermore, the raw materials for the basic chloride composite salt are: the base is preferably sodium hydroxide, sodium carbonate, sodium bicarbonate and other sodium salts, and the acid is preferably hydrochloric acid, chloric acid, perchloric acid and other chloric acid-containing acids; further, the configuration ratio is acid:base = 1:1-1.05, that is, the base is slightly excessive.

[0048] Furthermore, the alkali washing process in S5 is: adding the prepared alkaline chloride complex salt until the pH is between 12-14, stirring at a rate of 200-600 rpm, and stirring for 0.1-1h (the alkali washing time should not be too long, as it will damage the surface morphology).

[0049] Furthermore, the water washing process in S5 is: drain the raw material after alkali washing, add hot water, the amount of hot water added is 2-4 times the volume of the material, stir manually for half an hour and then soak for two hours, then drain the hot water, repeat the operation 6-8 times until the pH of the mother liquor is <9.

[0050] Furthermore, the drying process in S5 is: temperature 150-300° C., drying time 6-36 hours (to fully dry the surface moisture).

[0051] The quaternary precursor material prepared by the preparation method provided by the present invention is sintered at 950-1200° C. for 16-30 hours and then crushed to form a sodium ion battery positive electrode quaternary material.

[0052] The present invention also provides a sodium ion battery comprising a positive electrode, a negative electrode, an electrolyte, and a separator, wherein the positive electrode comprises the above-mentioned sodium ion battery positive electrode quaternary material.

[0053] Compared with the prior art, the present invention has the following beneficial effects:

[0054] 1. The material prepared by the present invention has a metal core, which improves the material's vibration compaction and energy density.

[0055] 2. The material prepared by the present invention has an intermediate carbon layer, which makes the initial growth process smoother while improving the electronic conductivity of the material and the rate performance.

[0056] 3. The material prepared by the present invention has a uniform internal structure, uniform particle distribution, and uniform stress distribution inside the particles, which reduces the generation of fine powder after sintering.

[0057] 4. The preparation method provided by the present invention makes the initial reaction process more stable by adding some nano-scale acid-treated and carbonized metal cores before the reaction.

[0058] 5. The preparation process of the present invention continuously adds nano-scale acid-treated and carbonized metal cores, which effectively buffers the effects of pH and ammonia value parameter fluctuations on particle growth.

[0059] 6. The preparation method of the present invention adopts a multi-point feeding method in which the doped salt solution is fed from four tubes and the remaining materials are fed from one tube, so that the local reaction at the feed tube mouth is more sufficient, ensuring that the precipitation rate at all parts of the reactor is consistent, the system is stable, and the controllability is high, which significantly improves the metal precipitation rate and has high process applicability.

[0060] 7. The preparation method of the present invention adopts an alkaline chlorination composite salt washing process. On the one hand, hydroxide replaces sulfate in the crystal lattice, which can significantly reduce the sulfur content. The residual chloride ions have strong oxidizing properties, and the surface potential is further enhanced, which effectively prevents carbon dioxide in the air from reacting with residual moisture in the particles to form residual alkali. The reaction of generating residual alkali is a process that enhances the potential of the particles. The increase of chloride ions makes the material have a higher ionic potential, which causes the original residual alkali reaction equilibrium to shift to the left, thereby reducing the generation of residual alkali.

[0061] 8. The material prepared by the present invention has a low residual alkali content, fewer side reactions during the charge and discharge process, and better electrical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in this application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0063] Figure 1 This is an SEM image of the quaternary precursor material prepared in Example 1 of the present invention.

[0064] Figure 2 This is an SEM image of the quaternary precursor material prepared in Example 2 of the present invention.

[0065] Figure 3 This is an SEM image of the quaternary precursor material prepared in Example 3 of the present invention.

[0066] Figure 4 This is an SEM image of the quaternary precursor material prepared in Example 4 of the present invention.

[0067] Figure 5 This is an SEM image of the quaternary precursor material prepared in Example 5 of the present invention.

[0068] Figure 6 This is an SEM image of the quaternary precursor material prepared in Example 6 of the present invention.

[0069] Figure 7 This is an SEM image of the quaternary precursor material prepared in Example 7 of the present invention.

[0070] Figure 8 This is an SEM image of the quaternary precursor material prepared in Example 8 of the present invention.

[0071] Figure 9 This is an SEM image of the quaternary precursor material prepared in Example 9 of the present invention.

[0072] Figure 10 This is an SEM image of the quaternary precursor material prepared in Example 10 of the present invention.

[0073] Figure 11 This is an SEM image of the quaternary precursor material prepared in Example 11 of the present invention.

[0074] Figure 12 This is an SEM image of the quaternary precursor material prepared in Example 12 of the present invention.

[0075] Figure 13 This is an SEM image of the quaternary precursor material prepared in Example 13 of the present invention.

[0076] Figure 14This is an SEM image of the quaternary precursor material prepared in Example 14 of the present invention.

[0077] Figure 15 This is an SEM image of the quaternary precursor material prepared in Example 15 of the present invention.

[0078] Figure 16 This is an SEM image of the quaternary precursor material prepared in Comparative Example 1 of the present invention.

[0079] Figure 17 This is an SEM image of the quaternary precursor material prepared in Comparative Example 2 of the present invention.

[0080] Figure 1 8 is a SEM image of the quaternary precursor material prepared in Comparative Example 3 of the present invention.

[0081] Figure 19 This is an SEM image of the quaternary precursor material prepared in Comparative Example 4 of the present invention.

[0082] Figure 20 This is an SEM image of the quaternary precursor material prepared in Comparative Example 5 of the present invention. DETAILED DESCRIPTION

[0083] The present invention will be more fully understood through the following detailed description, which should be read in conjunction with the accompanying drawings. Detailed embodiments of the present invention are disclosed herein; however, it should be understood that the disclosed embodiments are merely exemplary of the present invention, which can be embodied in various forms. Therefore, the specific functional details disclosed herein should not be construed as limiting, but rather as a basis for the claims and as a representative basis for teaching those skilled in the art to employ the present invention in various ways in virtually any appropriately detailed embodiment.

[0084] Example 1

[0085] This embodiment provides a quaternary precursor material, and the preparation method includes the following steps:

[0086] (1) Weigh 5000g of Cu powder (pure copper) and put it into a grinder at a grinding speed of 3000rpm. The grinding medium is zirconia balls with a size of 20μm. Grind for 6h to obtain metal cores. The metal core particle size D50 is 10-200nm. The ground Cu powder is placed in HNO3 (mass fraction 45%) for acidification. The acid treatment will corrode the surface of the metal core and make it rough, which is convenient for subsequent treatment. The molar ratio of HNO3:Cu is 1:10. Stir at 600rpm for 0.8h. The stirring time should not be too long. If the stirring time is too long, the surface reaction will be sufficient and a smooth structure will be easily formed. After acid treatment, it is placed in 80℃ warm water for washing. The weight ratio of water:material is 1:0.6. The washing time is 2h. Wash until the pH is 7. After washing, filter the water and dry at 150℃ for 36h for standby use. The treated metal core is recorded as M1.

[0087] (2) Add a certain amount of carbon powder, thickener and binder to anhydrous ethanol, the thickener is an acrylic thickener, the binder is a conductive binder prepared by mixing toughened epoxy resin, silver powder, 4-methylimidazole and ethylene glycol in a mass ratio of 95:3:2:56, and the addition ratio is carbon powder: thickener: binder molar ratio = 90:5:5. After the addition is completed, continue to add ethanol to adjust the viscosity to 3560mPa·s, at which time the solid content is 45.1%; add M1 to the mixed slurry, the addition amount of M1 is 3000ppm, stir at 200rpm, take out after 4h, place in a vacuum oven at 60℃, dry for 24h and discharge, the treated metal core is recorded as M2; on the one hand, the carbonization treatment makes the primary particles in the subsequent precipitation process more ideal and not easy to fall off, increases the connection force of the transition zone (that is, the interface between the metal core surface and the primary particles), and on the other hand, increases the conductivity of the particles.

[0088] (3) Sodium hydroxide solution (8 mol / L), ammonia solution (4 mol / L), nickel iron manganese sulfate solution (4 mol / L), wherein the nickel iron manganese sulfate solution is configured in a molar ratio of nickel: iron: manganese of 1:1:1, and copper sulfate solution (4 mol / L) were prepared respectively; 50 L of unsalted water was added to the reactor, 4.8 mol of M2 was added, and alkali solution was added to adjust the pH to 10. The mixture was stirred at 600 rpm, nitrogen was turned on, and the temperature was raised to 50 ° C at a rate of 2 ° C / min.

[0089] (4) Add the prepared metal salt mixture, copper sulfate solution, sodium hydroxide solution, ammonia solution and carbonized metal core M2 into the reactor simultaneously, and add the metal salt mixture, copper sulfate solution, sodium hydroxide solution and ammonia solution in a molar ratio of 1:1:0.8:0.2, wherein the copper sulfate solution flows in parallel from four pipes, two short and two long, symmetrically distributed, and the other materials flow in separately from one pipe. The flow rate of sodium hydroxide solution is continuously adjusted during the process, and the pH value of the control system remains unchanged. The amount of metal core M2 added per hour is 0.05 of the total molar amount of the total feed per hour. During the coprecipitation reaction, the pH is 9, the stirring is 500 rpm, the oxygen content is <5%, the ammonia concentration is 2 g / L, and the temperature is 50°C; when the particle size grows to 4.2 μm, the addition of raw materials is stopped.

[0090] (5) Alkaline chloride compound salt is prepared in a molar ratio of acidic substance: alkaline substance = 1:1-1.05, and the pH value after preparation is 13.18. Here, hydrochloric acid is selected as the acidic substance, and sodium hydroxide is selected as the alkaline substance. The prepared alkaline chloride compound salt is added to the reactor after the shutdown of step (4), and the pH value in the reactor is adjusted to 12.50. After stirring at 400 rpm for 0.2 h, the material is discharged; hot water twice the volume of the material is added to the barrel, and the material is manually stirred for half an hour and then soaked for two hours, and then the hot water is drained. The operation is repeated 8 times, and the pH value of the mother liquor after washing is 8.75; the washed material is placed in a blast oven at a temperature of 150°C and dried for 24 h, thus obtaining Ni 0.3 Fe 0.3 Mn 0.3 Cu 0.1 Quaternary precursor of (OH)2.

[0091] Example 2

[0092] The only difference between Example 2 and Example 1 is that the molar ratio of HNO3:Cu in Example 2 is 1:100, and the other conditions remain the same as in Example 1.

[0093] Example 3

[0094] The only difference between Example 3 and Example 1 is that the organic solvent in Example 3 is triethanolamine, and the other conditions remain the same as in Example 1.

[0095] Example 4

[0096] The only difference between Example 4 and Example 1 is that the organic solvent in Example 4 is styrene, and the other conditions remain the same as in Example 1.

[0097] Example 5

[0098] The only difference between Example 5 and Example 1 is that the molar ratio of carbon powder: thickener: binder added in Example 5 is 95:2:3, and the other conditions remain the same as in Example 1.

[0099] Example 6

[0100] The only difference between Example 6 and Example 1 is that the amount of metal core M1 added in Example 6 is 50,000 ppm of the total feed amount per hour, and the other conditions remain the same as in Example 1.

[0101] Example 7

[0102] The only difference between Example 7 and Example 1 is that the amount of metal core M2 added in Example 7 is 0.5 of the total feed mole per hour, and the other conditions remain the same as in Example 1.

[0103] Example 8

[0104] The only difference between Example 8 and Example 1 is that the pH in Example 8 was adjusted from 9 to 10.0 during the co-precipitation reaction, and the other conditions remained the same as in Example 1.

[0105] Example 9

[0106] The only difference between Example 9 and Example 1 is that the pH in Example 9 was adjusted from 9 to 11.0 during the coprecipitation reaction, and the other conditions remained the same as in Example 1.

[0107] Example 10

[0108] The only difference between Example 10 and Example 1 is that the pH in Example 10 was adjusted from 9 to 12.0 during the co-precipitation reaction, and the other conditions remained the same as in Example 1.

[0109] Example 11

[0110] The only difference between Example 11 and Example 1 is that the stirring during the co-precipitation reaction in Example 11 is adjusted from 500 rpm to 400 rpm, and the other conditions remain the same as in Example 1.

[0111] Example 12

[0112] The only difference between Example 12 and Example 1 is that the stirring during the co-precipitation reaction in Example 12 is adjusted from 500 rpm to 600 rpm, and the other conditions remain the same as in Example 1.

[0113] Example 13

[0114] The only difference between Example 13 and Example 1 is that the ammonia concentration during the co-precipitation reaction in Example 13 is adjusted from 2 g / L to 4 g / L, and the other conditions remain the same as in Example 1.

[0115] Example 14

[0116] The only difference between Example 14 and Example 1 is that the ammonia concentration during the co-precipitation reaction in Example 14 was adjusted from 2 g / L to 6 g / L, and the other conditions remained the same as in Example 1.

[0117] Example 15

[0118] The only difference between Example 15 and Example 1 is that the ammonia concentration during the co-precipitation reaction in Example 15 was adjusted from 2 g / L to 8 g / L, and the other conditions remained the same as in Example 1.

[0119] Example 16

[0120] The only difference between Example 16 and Example 1 is that in Example 16, sodium hydroxide solution (4 mol / L), ammonia solution (3 mol / L), nickel-iron-manganese sulfate solution (2 mol / L) were prepared respectively, wherein the nickel-iron-manganese sulfate solution was configured in a molar ratio of nickel: iron: manganese of 0.1:0.1:0.8, and copper sulfate solution (2 mol / L); 50 L of unsalted water was added to the reactor, 0.5 mol of M2 was added, alkali solution was added to adjust the pH to 11, stirred at 600 rpm, nitrogen was turned on, and the temperature was slowly raised to 50° C., and the other conditions were consistent with Example 1.

[0121] Example 17

[0122] The only difference between Example 17 and Example 1 is that in Example 17, sodium hydroxide solution (10 mol / L), ammonia solution (12 mol / L), nickel-iron-manganese sulfate solution (8 mol / L) were prepared respectively, wherein the nickel-iron-manganese sulfate solution was configured in a molar ratio of nickel: iron: manganese of 0.8:0.1:0.1, and copper sulfate solution (8 mol / L); 50 L of salt-free water was added to the reactor, 10 mol of M2 was added, alkali solution was added to adjust the pH to 11, the mixture was stirred at 600 rpm, nitrogen was turned on, and the temperature was slowly raised to 50° C., and the other conditions were consistent with Example 1.

[0123] Example 18

[0124] The only difference between Example 18 and Example 1 is that in Example 18, the metal salt mixture, copper sulfate solution, sodium hydroxide solution, and ammonia solution are added in a molar ratio of 1:1:0.2:0.6, and the other conditions remain the same as in Example 1.

[0125] Comparative Example 1

[0126] Comparative Example 1 provides a quaternary precursor material, and the preparation method includes the following steps:

[0127] S1. Prepare sodium hydroxide solution (8 mol / L), ammonia solution (4 mol / L), nickel iron manganese copper sulfate solution (4 mol / L), and nickel iron manganese copper sulfate solution in a ratio of 0.3:0.3:0.3:0.1 respectively; add 50 L of unsalted water to the reactor, add alkali solution to adjust the pH to 10.02, stir at 600 rpm, turn on nitrogen, and slowly heat to 50°C;

[0128] S2. Simultaneously, the configured nickel-iron-manganese-copper sulfate solution, sodium hydroxide solution, and ammonia solution are introduced into the reactor in parallel, with a molar ratio of nickel-iron-manganese-copper: alkali: ammonia solution = 1.0:0.5:0.4. The materials are all introduced in parallel through a single pipe. The flow rate of sodium hydroxide solution is continuously adjusted during the process to control the pH value of the system to remain unchanged. During the coprecipitation reaction, the pH is 10.06, the stirring is 500 rpm, the oxygen content is <5%, the ammonia concentration is 2 g / L, and the temperature is 50 ° C; the particle size grows to 4.2 μm and the qualified shutdown is completed;

[0129] S3, according to the acid: base = 1: 1-1.01 basic chloride compound salt is prepared, the pH after preparation is 13.04, the acid is hydrochloric acid, the base is sodium hydroxide, the prepared basic chloride compound salt is added to the reactor after the shutdown in step S4, the pH in the reactor is adjusted to 12.43, and after stirring at 400 rpm for 0.2h, the material is discharged; hot water twice the volume of the material is added to the barrel, manually stirred for half an hour and then soaked for two hours, and then the hot water is drained, and the operation is repeated 8 times. After washing, the pH of the mother liquor is 8.88; the washed material is placed in a blast oven at a temperature of 150 ° C and dried for 24h to obtain Ni 0.3 Fe 0.3 Mn 0.3 Cu 0.1 Quaternary precursor of (OH)2.

[0130] Comparative Example 2

[0131] Comparative Example 2 provides a quaternary precursor material, the preparation method of which includes the following steps:

[0132] S1. Weigh 5000 g of Cu powder and put it into a grinder at a grinding speed of 3000 rpm. The grinding medium is zirconia balls with a size of 20 μm. Grind for 6 h and discharge the material. The ground Cu powder is placed in HNO3 for acidification with a molar ratio of HNO3:Cu of 1:10 and stirred at 600 rpm. After stirring for 0.3 h, it is placed in 80°C warm water with a water-to-material ratio of 1:0.6. The washing time is 2 h until the pH is about 7. After completion, the water is filtered and dried for later use. The metal cores processed here are recorded as M1.

[0133] S2. Prepare sodium hydroxide solution (8 mol / L), ammonia solution (4 mol / L), nickel iron manganese copper sulfate solution (4 mol / L), and nickel iron manganese copper sulfate solution with a molar ratio of Ni:Fe:Mn:Cu=0.3:0.3:0.3:0.1 respectively; add 50 L of unsalted water to the reactor, add 4.8 mol of M1, add alkali solution to adjust the pH to 10.07, stir at 600 rpm, turn on nitrogen, and slowly heat to 50°C;

[0134] S3. Simultaneously, the prepared nickel-iron-manganese-copper sulfate solution, sodium hydroxide solution, and ammonia solution are introduced into the reactor in parallel, with a molar ratio of nickel-iron-manganese-copper: alkali solution: complexing agent = 1.0:0.5:0.4. The materials are all introduced in parallel through a single pipe. The flow rate of sodium hydroxide solution is continuously adjusted during the process to control the pH value of the system to remain unchanged. During the coprecipitation reaction, the pH is 10.04, the stirring is 500 rpm, the oxygen content is <5%, the ammonia concentration is 2 g / L, and the temperature is 50°C; the particle size grows to 4.2 μm and the process is stopped;

[0135] S4, according to the acid: base = 1: 1-1.01 basic chloride compound salt is prepared, the pH after preparation is 13.01, the acid is hydrochloric acid, the base is sodium hydroxide, the prepared basic chloride compound salt is added to the reactor after the shutdown of step S4, the pH in the reactor is adjusted to 12.38, at 400rpm, after stirring for 0.2h, the material is discharged; hot water twice the volume of the material is added to the barrel, manually stirred for half an hour and then soaked for two hours, then the hot water is drained, the operation is repeated 8 times, the pH of the mother liquor after washing is 8.67; the washed material is placed in a blast oven at a temperature of 150°C and dried for 24h to obtain Ni 0.3 Fe 0.3 Mn 0.3 Cu 0.1 Quaternary precursor of (OH)2.

[0136] Comparative Example 3

[0137] Comparative Example 3 provides a quaternary precursor material, the preparation method of which includes the following steps:

[0138] S1. Weigh 5000 g of Cu powder and put it into a grinder at a grinding speed of 3000 rpm. The grinding medium is zirconia balls with a size of 20 μm. Grind for 6 h and discharge the material. The ground Cu powder is placed in HNO3 for acidification with a molar ratio of HNO3:Cu of 1:10 and stirred at 600 rpm. After stirring for 0.3 h, it is placed in 80°C warm water with a water-to-material ratio of 1:0.6. The washing time is 2 h until the pH is about 7. After completion, the water is filtered and dried for later use. The metal cores processed here are recorded as M1.

[0139] S2. Prepare sodium hydroxide solution (8 mol / L), ammonia solution (4 mol / L), nickel iron manganese sulfate solution (4 mol / L), nickel iron manganese sulfate solution with a molar ratio of Ni:Fe:Mn=0.3:0.3:0.3, and copper sulfate solution (0.5 mol / L) respectively; add 50 L of unsalted water to the reactor, add 4.8 mol of M1, add alkali solution to adjust the pH to 10.0, stir at 600 rpm, turn on nitrogen, and slowly heat to 50°C;

[0140] S3 simultaneously introduces the prepared metal salt mixture, copper sulfate solution, sodium hydroxide solution, and ammonia solution into the reactor in parallel, with a molar ratio of nickel, iron, and manganese: copper: alkali: ammonia solution = 0.9:0.1:0.5:0.4. The copper sulfate solution enters from four pipes in parallel, and the other materials enter from a single pipe in parallel. The flow rate of the sodium hydroxide solution is continuously adjusted during the process to control the pH value of the system to remain unchanged. During the coprecipitation reaction, the pH is 10.01, the stirring speed is 500 rpm, the oxygen content is <5%, the ammonia concentration is 2 g / L, and the temperature is 50°C; the process is stopped when the particle size reaches 4.2 μm.

[0141] S4, according to the acid: base = 1: 1-1.01 basic chloride compound salt is prepared, the pH after preparation is 13.05, the acid is hydrochloric acid, the base is sodium hydroxide, the prepared basic chloride compound salt is added to the reactor after the shutdown of step S4, the pH in the reactor is adjusted to 12.46, stirred at 400 rpm, stirred for 0.2h, and then discharged; hot water twice the volume of the material is added to the barrel, manually stirred for half an hour and then soaked for two hours, then the hot water is drained, and the operation is repeated 8 times. After washing, the pH of the mother liquor is 8.45; the washed material is placed in a blast oven at a temperature of 150°C and dried for 24h to obtain Ni 0.3 Fe 0.3 Mn 0.3 Cu 0.1 Quaternary precursor of (OH)2.

[0142] Comparative Example 4

[0143] Comparative Example 4 provides a quaternary precursor material, the preparation method of which includes the following steps:

[0144] S1. Weigh 5000 g of Cu powder and put it into a grinder at a grinding speed of 3000 rpm. The grinding medium is zirconia balls with a size of 20 μm. Grind for 6 h and discharge the material. The ground Cu powder is placed in HNO3 for acidification with a molar ratio of HNO3:Cu of 1:10 and stirred at 600 rpm. After stirring for 0.3 h, it is placed in 80°C warm water with a water-to-material ratio of 1:0.6. The washing time is 2 h until the pH is about 7. After completion, the water is filtered and dried for later use. The metal cores processed here are recorded as M1.

[0145] S2, adding a certain amount of carbon powder, thickener and binder to anhydrous ethanol, wherein the thickener is an acrylic thickener, and the binder is a conductive binder prepared by mixing toughened epoxy resin, silver powder, 4-methylimidazole and ethylene glycol in a mass ratio of 95:3:2:56, and the addition ratio is carbon powder: thickener: binder = 90:5:5. After the addition is completed, ethanol is continued to be added to adjust the viscosity to 3850 mPa·s, at which time the solid content is 46.2%; M1 is added to the slurry in an amount of 3000 ppm, stirred at 200 rpm, and removed after 4 hours. After removal, the slurry is placed in a vacuum oven at 60°C and dried for 24 hours. The metal core processed here is recorded as M2;

[0146] S3, respectively prepare sodium hydroxide solution (8 mol / L), ammonia solution (4 mol / L), nickel iron manganese sulfate solution (4 mol / L), nickel iron manganese sulfate solution configuration ratio of 0.3:0.3:0.3, copper sulfate solution (0.5 mol / L); add 50 L of salt water to the reactor, add 4.8 mol of M2, add alkali solution to adjust the pH to 10.11, stir at 600 rpm, turn on nitrogen, and slowly heat to 50 ° C;

[0147] S4. Simultaneously, the configured metal salt mixture, copper sulfate solution, sodium hydroxide solution, and ammonia solution are introduced into the reactor in parallel, with a molar ratio of nickel, iron, and manganese: copper: alkali: ammonia: M2 = 0.9:0.1:0.5:0.4. The copper sulfate solution flows in parallel from four pipes, and the other materials flow in parallel from one pipe alone. The flow rate of the sodium hydroxide solution is continuously adjusted during the process to keep the pH value of the control system unchanged. During the coprecipitation reaction, the pH is 10.06, the stirring is 500 rpm, the oxygen content is <5%, the ammonia concentration is 2 g / L, and the temperature is 50 ° C; the particle size grows to 4.2 μm and the qualified shutdown is completed;

[0148] S5, according to the acid: base = 1: 1-1.01 basic chloride compound salt is prepared, the pH value after preparation is 13.10, the acid is hydrochloric acid, the base is sodium hydroxide, the prepared basic chloride compound salt is added to the reactor after the shutdown of step S4, the pH value in the reactor is adjusted to 12.53, stirred at 400 rpm, stirred for 0.2h, and then discharged; hot water twice the volume of the material is added to the barrel, manually stirred for half an hour and then soaked for two hours, then the hot water is drained, and the operation is repeated 8 times, and the pH value of the mother liquor after washing is 8.62; the washed material is placed in a blast oven at a temperature of 150°C and dried for 24h to obtain Ni 0.3 Fe 0.3 Mn 0.3 Cu 0.1 Quaternary precursor of (OH)2.

[0149] Comparative Example 5

[0150] Comparative Example 5 provides a quaternary precursor material, the preparation method of which includes the following steps:

[0151] S1. Weigh 5000g of Cu powder and put it into a grinder at a grinding speed of 3000rpm. The grinding medium is zirconia balls with a size of 20um. Grind for 6h and discharge the material. The ground Cu powder is placed in HNO3 for acidification with a molar ratio of HNO3:Cu of 1:10 and stirred at 600rpm. After stirring for 0.3h, it is placed in 80°C warm water with a water to material ratio of 1:0.6. The washing time is 2h until the pH is about 7. After completion, the water is filtered and dried for later use. The metal cores processed here are recorded as M1.

[0152] S2, adding a certain amount of carbon powder, thickener and binder to anhydrous ethanol in a ratio of carbon powder: thickener: binder = 90:5:5. After the addition is completed, continue to add ethanol to adjust the viscosity to 3721mPa·s, at which time the solid content is 45.8%; add M1 to the slurry in an amount of 3000ppm, stir at 200rpm, remove after 4h, place in a vacuum oven at 60°C, and dry for 24h. The metal cores completed here are recorded as M2;

[0153] S3, respectively prepare sodium hydroxide solution (8 mol / L), ammonia solution (4 mol / L), nickel iron manganese sulfate solution (4 mol / L), nickel iron manganese sulfate solution in a ratio of 0.3:0.3:0.3, and copper sulfate solution (0.5 mol / L); add 50 L of unsalted water to the reactor, add 4.8 mol of M2, add alkali solution to adjust the pH to 10.15, stir at 600 rpm, turn on nitrogen, and slowly heat to 50 ° C;

[0154] S4. Simultaneously, the configured metal salt mixture, copper sulfate solution, sodium hydroxide solution, and ammonia solution are introduced into the reactor in parallel, with a molar ratio of nickel, iron, and manganese: copper: alkali: ammonia: M2 = 0.9:0.1:0.5:0.4. The copper sulfate solution flows in parallel from four pipes, and the other materials flow in parallel from one pipe alone. The flow rate of the sodium hydroxide solution is continuously adjusted during the process to keep the pH value of the control system unchanged. During the coprecipitation reaction, the pH is 10.08, the stirring is 500 rpm, the oxygen content is <5%, the ammonia concentration is 2 g / L, and the temperature is 50 ° C; the particle size grows to 4.2 μm and the qualified shutdown discharge is completed;

[0155] S5. Add hot water twice the volume of the material into the discharge barrel, stir manually for half an hour and then soak for two hours, then drain the hot water, repeat the operation 8 times, and the pH value of the mother liquor after washing is 8.44; place the washed material in a blast oven at 150°C and dry it for 24 hours to obtain Ni 0.3 Fe 0.3 Mn 0.3 Cu0.1 Quaternary precursor of (OH)2.

[0156] Performance Characterization

[0157] The morphologies of the quaternary material precursors prepared in Examples 1-9 and Comparative Examples 1-5 were observed under a scanning electron microscope. The corresponding SEM images are shown in Figure 1-14 .

[0158] It can be seen that the precursor materials prepared in Examples 1-9 have uniform internal structures, and the primary particles (small particles generated during the particle synthesis and growth process) are evenly distributed without agglomeration, which can reduce the generation of fine powder after sintering.

[0159] The quaternary precursor materials prepared in Examples 1-18 and Comparative Examples 1-5 of the present invention were sintered at 950-1200° C. for 16-30 h and then broken into sodium ion quaternary materials.

[0160] All sodium ion quaternary materials in the present invention are made into button batteries to test their electrochemical properties. The battery manufacturing process follows the following steps:

[0161] According to the positive electrode material: carbon nanotube (CNT): PVDF (Solvay 5130) = 90:5:5, a certain amount of NMP was added to mix and slurry, and after coating and drying, the electrode surface density was 8 mg / cm 3 After rolling on a small roller press, the pole piece compaction is 1.6g / cm 3 , cut into 14mm circular electrode pieces and placed in the glove box for standby use; use sodium sheet as the battery's counter electrode, choose sodium perchlorate electrolyte, choose Xingyuan's ceramic diaphragm, cut into 16mm circular pieces, and assemble into CR2032 button batteries in the order of positive electrode shell, positive electrode sheet, diaphragm, negative electrode sheet, gasket, spring and negative electrode shell. The test voltage is 2.0-4.1V, and the test equipment is LAND;

[0162] The quaternary precursor materials prepared in Examples 1-9 and Comparative Examples 1-5 were made into sodium ion quaternary materials, installed on button batteries, and their electrochemical properties were tested. The test results are shown in Table 1.

[0163] Table 1 Comparison of electrochemical performance of sodium ion batteries made from quaternary precursor materials prepared in Examples 1-9 and Comparative Examples 1-5

[0164]

[0165]

[0166] From the test data in Table 1, it can be seen that the performance of the batteries made using the quaternary precursor materials prepared in Examples 1-18 is higher than that of the batteries made using the quaternary precursor materials prepared in Comparative Examples 1-5.

[0167] Comparing Example 1 with Comparative Example 1, in Example 1, the original core is artificially added to make the initial startup process more stable, and the nano-scale metal after acid treatment and carbonization treatment is used as the original core, which reduces the difficulty of forming the core and improves the material compaction.

[0168] Comparing Example 1 with Comparative Examples 2-3, Example 1 uses a carbon layer to coat the protonuclei, facilitating the bonding of primary particles and smoothing their growth, thereby improving electronic conductivity and enhancing the electrochemical performance of the battery. Compared with Comparative Example 2, in Example 1, the copper sulfate solution is fed in parallel through four pipes, while the other materials are fed in parallel through a single pipe. This multi-point feeding method ensures a consistent precipitation rate across the reactor, resulting in a stable and highly controllable system and, ultimately, impressive electrochemical performance for the battery.

[0169] Comparative Examples 1 and 4: In Example 1, the original cores were continuously added during the process of Example 1, which effectively buffered the effects of fluctuations in parameters such as pH and ammonia on particle growth and improved the electrochemical performance of the material.

[0170] Comparing Example 1 and Comparative Example 5, Example 1 adopts an alkali washing process. On the one hand, hydroxide replaces sulfate in the crystal lattice, which can significantly reduce the sulfur content. The residual chloride ions have strong oxidizing properties, and the surface potential is further enhanced, which effectively prevents the carbon dioxide in the air from reacting with the residual moisture in the particles to generate residual alkali (the reaction to generate residual alkali is the process of enhancing the particle potential. The increase of chloride ions makes the material have a higher ionic potential, so that the original residual alkali reaction equilibrium shifts to the left, thereby reducing the generation of residual alkali).

[0171] The various aspects, embodiments, features and examples of the present invention should be considered as illustrative in all respects and are not intended to limit the present invention, the scope of which is defined solely by the claims. Other embodiments, modifications and uses will be apparent to those skilled in the art without departing from the spirit and scope of the invention as claimed.

Claims

1. A method for preparing a quaternary precursor material, characterized in that: The following steps are involved: S1. The metal is ground to the nanometer scale, and then subjected to acid treatment to obtain an acidified metal core; wherein the acid treatment comprises mixing the ground metal with an oxidizing acid in a molar ratio of 1:10-100, and then washing and drying. S2. Add carbon powder to an organic solvent, then add a thickener and a binder to adjust the viscosity, and then add the acidified metal core in S1, stir and dry; the drying temperature is 60 ° C, and the drying time is 24h; S3 is added to the bottom liquid S2 after drying the carbonized metal core, and then add alkali solution to adjust the pH, into the protective gas; S4. An alkali solution, a metal salt mixture, a doping salt solution, and a complexing agent solution are mixed to form a mixed reaction solution. While the mixed reaction solution is being formed, the carbonized metal cores in S2 are added for precipitation reaction to obtain a precipitated material; wherein the metal salt mixture is a ternary mixed salt solution having a Ni:Fe:Mn molar ratio of 0.1-0.8:0.1-0.8:0.1-0.8; the doping salt solution is the salt solution of the metal added in S1; the amount of the metal core added is 0.05-0.5 of the total molar amount of the metal salt mixture, the doping salt solution, the alkali solution, and the complexing agent solution added per hour; the doping salt solution enters the reactor through four tubes, two short and two long, symmetrically distributed; S5. The precipitated material is added to a basic chloride complex salt for washing and then post-processed to obtain the quaternary precursor material, wherein the pH of the basic chloride complex salt is adjusted to 12-14 and added, and stirred at 200-600 rpm for 0.1-1h.

2. The method for preparing a quaternary precursor material according to claim 1, wherein: Grinding the metal until the metal core particle size D50 is 10-200 nm, wherein the metal comprises one or more of Cu, Zr, Zn, Ti, Mg, Al, Y, La, and W; The oxidizing acid used in the acid treatment includes any one or more combinations of nitric acid, chloric acid, perchloric acid, and concentrated sulfuric acid.

3. The method for preparing the quaternary precursor material according to claim 1, wherein: The organic solvent includes any one of anhydrous ethanol, triethanolamine, and styrene; And / or, the thickener includes an acrylic thickener, the binder includes a conductive binder formed by mixing toughened epoxy resin, silver powder, 4-methylimidazole, and a solvent, the carbon powder, thickener, and binder are mixed in a molar ratio of 90-95:2-5:3-5, and the solid content after mixing is 40-60%; And / or, the added amount of the metal core in S2 is 3000-50000 ppm.

4. The method for preparing a quaternary precursor material according to claim 1, wherein: The base liquid includes a non-salted water, and the concentration of the alkali solution is 4-10 mol / L; and / or, the concentration of the metal salt mixture is 2-8 mol / L; and / or, the concentration of the doping salt solution is 2-8 mol / L; and / or, the concentration of the complexing agent solution is 3-12 mol / L; and / or, adding the alkaline solution in S3 to adjust the pH to 10-11; and / or, the amount of the metal core added in S3 is 0.5-10 mol; and / or, the protective gas comprises nitrogen; And / or, S3 further includes stirring and heating to 50-80° C. after introducing protective gas.

5. The method for preparing the quaternary precursor material according to claim 4, characterized in that: The alkali solution includes any one of potassium hydroxide and sodium hydroxide solution or a combination of the two; and / or, the complexing agent solution comprises an aqueous ammonia solution; and / or, the metal salt mixture, the doping salt solution, the alkali solution, and the complexing agent solution are mixed in a molar ratio of 1:1:0.2-0.8:0.2-0.6 to form the mixed reaction solution; And / or, in S4, the pH of the precipitation reaction process is 9-12, the percentage of oxygen is less than 5%, and the concentration of ammonia is 2-8 g / L; And / or, no more reaction raw materials are added when the particle size reaches 3-15 μm.

6. The method for preparing the quaternary precursor material according to claim 1, characterized in that include: The basic chlorinated composite salt is prepared from an acidic substance and an alkaline substance in a molar ratio of acidic substance to alkaline substance = 1:1-1.05, wherein the acidic substance includes any one of hydrochloric acid, chloric acid, and perchloric acid, and the alkaline substance includes any one of sodium hydroxide, sodium carbonate, and sodium bicarbonate; And / or, the post-treatment includes draining the raw material after washing with the basic chloride composite salt, repeatedly adding water, stirring, and soaking until the pH value of the solution is less than 9, and then drying.

7. A quaternary precursor material, prepared by the preparation method according to any one of claims 1 to 6.

8. A sodium ion battery cathode quaternary material, characterized in that: The method comprises sintering the quaternary precursor material according to claim 7 at 950-1200° C. for 16-30 hours and then breaking the quaternary precursor material to form the sodium ion battery positive electrode quaternary material.

9. A sodium ion battery comprising a positive electrode, a negative electrode, an electrolyte, and a separator, characterized in that: The positive electrode comprises the sodium ion battery positive electrode quaternary material according to claim 8.

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