A nickel-manganese binary precursor, a preparation method and application thereof

Abstract

The application discloses a kind of nickel manganese binary precursor and its preparation method and application, belong to battery material technical field.The preparation method includes: in bottom liquid and flow joining mixed metal salt solution, precipitant, complexing agent, additive solution, raw material salt solution carry out coprecipitation reaction, until get preset particle size;Mixed metal salt solution is the mixed salt solution of soluble nickel salt and soluble manganese salt;Precipitant is sodium hydroxide solution;Complexing agent is ammonia water;Additive in additive solution includes sodium erythorbate, tea polyphenol, sodium tartrate and sodium sorbate;Raw material salt in raw material salt solution includes soluble iron salt, soluble molybdenum salt and soluble tellurium salt;The temperature of coprecipitation reaction is 40~80 ℃, and pH value is 8.5~12.0.The nickel manganese binary precursor has higher stability, and can be applied to prepare high-voltage spinel structure lithium nickel manganese oxide positive material or lithium-rich manganese-based positive material.

Description

Technical Field

[0001] This invention relates to the field of battery materials technology, and more specifically, to a nickel-manganese binary precursor, its preparation method, and its application. Background Technology

[0002] Lithium nickel manganese spinel oxide (LiNi) 0.5 Mn 1.5 Lithium nickel manganese oxide (Li₄) possesses advantages such as high operating voltage, three-dimensional lithium-ion diffusion channels, and low cost, making it a promising candidate material for next-generation fast-charging battery cathodes. Operating at around 4.7V, it offers high energy density, making it suitable for power batteries and high-rate applications. However, under high-voltage conditions, the inevitable two-phase reaction of lithium nickel manganese oxide leads to lattice strain and stress concentration, resulting in grain cracking, transition metal dissolution, and interface instability, ultimately causing insufficient cycle life. This problem is particularly pronounced under extreme operating conditions such as fast charging and high temperatures, severely limiting its practical application.

[0003] Manganese-rich cathode materials, with their advantages of high voltage and high specific energy, are considered one of the keys to breaking through the energy density limit of traditional lithium-ion batteries. However, lithium-rich manganese-based cathode materials still face some technical challenges in practical applications, such as significant voltage decay and capacity degradation during cycling. During cycling, the layered structure of lithium-rich manganese-based cathodes gradually transforms into spinel and rock salt structures, with weakened layered characteristic peaks and continuously enhanced spinel characteristic peaks. Some grains may also break down and become amorphous, directly lowering the average operating voltage of the material. During charge and discharge, oxygen activity exhibits significant asymmetry, and lattice energy accumulates continuously, driving irreversible structural transformations in the material. Under high voltage, reactive oxygen free radicals released from the lattice nucleophilically attack the electrolyte, triggering continuous side reactions and gas production. Simultaneously, a large amount of transition metal dissolves, further catalyzing electrolyte degradation, destroying the electrode structure, and accelerating the simultaneous decay of voltage and capacity.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a nickel-manganese binary precursor, its preparation method, and its application, so as to solve or improve the above-mentioned technical problems.

[0006] This invention can be implemented as follows: In a first aspect, the present invention provides a method for preparing a nickel-manganese binary precursor, comprising the following steps: A co-precipitation reaction is carried out by adding a mixed metal salt solution, precipitant, complexing agent, additive solution, and raw material salt solution to the bottom liquid in parallel flow until the preset particle size is obtained; the material obtained from the reaction is then subjected to solid-liquid separation, washing, and drying. The mixed metal salt solution is a mixed salt solution of soluble nickel salt and soluble manganese salt; the precipitant is sodium hydroxide solution; the complexing agent is ammonia water; the additives in the additive solution include sodium isoascorbate, tea polyphenols, sodium tartrate and sodium sorbate; the raw material salts in the raw material salt solution include soluble iron salt, soluble molybdenum salt and soluble tellurium salt. The coprecipitation reaction was carried out at a temperature of 40℃~80℃, a pH of 8.5~12.0, and a time of 50h~100h.

[0007] In an optional embodiment, the total concentration of Ni and Mn in the mixed salt solution is 0.1 mol / L to 2.5 mol / L; Ni:Mn=x:(1-x), 0.1≤x≤0.5.

[0008] In an optional embodiment, the concentration of the sodium hydroxide solution is 5 mol / L to 15 mol / L, and the ammonia content in the reaction slurry is controlled to be 0.1 mol / L to 1.0 mol / L.

[0009] In an optional embodiment, the concentration of the complexing agent is 5 mol / L to 10 mol / L.

[0010] In an optional embodiment, the ratio of the mixed salt solution to the additive is 1L:(1g~5g); In the additives, the mass ratio of sodium isoascorbate, tea polyphenols, sodium tartrate and sodium sorbate is (1~5):(1~5):(1~5):(1~5).

[0011] In an optional embodiment, the amounts of soluble iron salt, soluble molybdenum salt and soluble tellurium salt are set as follows: in the nickel-manganese binary precursor, Fe atoms account for 1% to 5% of the total metal moles, Mo atoms account for 0.1% to 1% of the total metal moles and Te atoms account for 0.1% to 1% of the total metal moles.

[0012] Secondly, the present invention provides a nickel-manganese binary precursor, which is prepared by any of the preparation methods described in the foregoing embodiments.

[0013] In an optional embodiment, the nickel-manganese binary precursor has at least one of the following characteristics: Feature 1: The particle size of the nickel-manganese binary precursor is 3μm~8μm; Feature 2: The tap density of the nickel-manganese binary precursor is ≥1.2 g / cm³. 3 ; Feature 3: The specific surface area of ​​the nickel-manganese binary precursor is 5m². 2 / g~25m 2 / g; Feature 4: The nickel-manganese binary precursor has a thick, plate-like insert structure.

[0014] In an optional embodiment, the sheet thickness of the nickel-manganese binary precursor is 200 nm to 600 nm.

[0015] Thirdly, the present invention provides a cathode material obtained by sintering the nickel-manganese binary precursor of the aforementioned embodiments with a lithium source.

[0016] Fourthly, the present invention provides a battery comprising the positive electrode material of the foregoing embodiments.

[0017] The beneficial effects of this invention include: In the co-precipitation process, this invention utilizes specific amounts of sodium isoascorbate, tea polyphenols, sodium tartrate, and sodium sorbate as additives to improve the morphology, structure, and particle size distribution of the precursor particles, as well as to prevent Mn oxidation. The addition of specific amounts of Fe, Mo, and Te doping ions helps to expand the ion diffusion channels of the cathode material, promote ion diffusion and migration, and improve the rate performance of the cathode material. Furthermore, it can suppress lattice distortion and improve structural stability. In addition, doping with high-valence metals can strengthen the MO bonds, stabilize the lattice structure, and further improve the structural stability of the cathode material.

[0018] The nickel-manganese binary precursor provided by this invention can be used to prepare high-voltage spinel-structured lithium nickel manganese oxide cathode materials and lithium-rich manganese-based cathode materials. The corresponding cathode materials have excellent electrochemical performance. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 The image shows a SEM image of the nickel-manganese binary precursor prepared in Example 1. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0022] The following is a detailed description of the nickel-manganese binary precursor, its preparation method, and its application provided by the present invention.

[0023] This invention provides a method for preparing a nickel-manganese binary precursor, comprising the following steps: adding a mixed metal salt solution, a precipitant, a complexing agent, an additive solution, and a raw material salt solution in parallel to a base liquid to carry out a co-precipitation reaction until a preset particle size is obtained; and performing solid-liquid separation, washing, and drying on the reacted material.

[0024] In some alternative embodiments, the temperature of the substrate is 40°C to 80°C, and the pH value is 8.5 to 12.0. In some more typical embodiments, the temperature of the substrate is 45°C to 60°C, and the pH value is 10.5 to 11.5.

[0025] In some optional embodiments, the mixed metal salt solution is a mixed salt solution of soluble nickel salt and soluble manganese salt, which, exemplarily, may include sulfate, nitrate, acetate, etc. In some optional embodiments, the total concentration of Ni and Mn in the mixed salt solution can be 0.1 mol / L to 2.5 mol / L, such as 0.1 mol / L, 0.5 mol / L, 1.0 mol / L, 1.5 mol / L, 2.0 mol / L, or 2.5 mol / L, or other values ​​within the range of 0.1 mol / L to 2.5 mol / L. Wherein, Ni:Mn = x:(1-x), 0.1 ≤ x ≤ 0.5; that is, x can be 0.1, 0.2, 0.3, 0.4, or 0.5, or other values ​​within the range of 0.1 to 0.5. In other words, the precursor in this invention is a manganese-rich precursor. In some typical embodiments, x is 0.2 to 0.3.

[0026] In some optional embodiments, the precipitant is a sodium hydroxide solution. The concentration of the sodium hydroxide solution can be 5 mol / L to 15 mol / L, such as 5 mol / L, 8 mol / L, 10 mol / L, 12 mol / L, or 15 mol / L, or other values ​​within the range of 5 mol / L to 15 mol / L. The reaction pH is adjusted and controlled by the precipitant. In some optional embodiments, the concentration of the sodium hydroxide solution is 5 mol / L to 10 mol / L.

[0027] In some optional embodiments, the complexing agent is ammonia. The concentration of the complexing agent can be 5 mol / L to 10 mol / L, such as 5 mol / L, 6 mol / L, 7 mol / L, 8 mol / L, 9 mol / L, or 10 mol / L, or other values ​​within the range of 5 mol / L to 10 mol / L. In some optional embodiments, the concentration of the complexing agent is 6 mol / L to 9 mol / L. The ammonia content in the reaction slurry is controlled to be 0.1 mol / L to 1.0 mol / L, such as 0.1 mol / L, 0.2 mol / L, 0.5 mol / L, 0.8 mol / L, or 1.0 mol / L, or other values ​​within the range of 0.1 mol / L to 1.0 mol / L.

[0028] In some optional embodiments, the additives in the additive solution simultaneously include sodium isoascorbate, tea polyphenols, sodium tartrate, and sodium sorbate. The mass ratio of sodium isoascorbate, tea polyphenols, sodium tartrate, and sodium sorbate can be (1~5):(1~5):(1~5):(1~5), such as 1:1:1:1, 1:2:1:2, or 2:1:3:1, or other values ​​within the range of (1~5):(1~5):(1~5):(1~5).

[0029] In the coprecipitation reaction, divalent manganese ions (Mn) 2+ Manganese (Mn) is readily oxidized to trivalent or tetravalent manganese by dissolved oxygen in water or oxygen in the environment, resulting in impure precursor phases and irregular particle morphology. This invention, by adding the aforementioned additives during the co-precipitation process, can improve the morphology, structure, and particle size distribution of the precursor particles, and prevent Mn oxidation. Sodium isoascorbate and tea polyphenols work together to prevent oxidation, maintaining the stable divalent state of manganese throughout the reaction. Sodium tartrate can complex metal ions, control the precipitation rate, promote uniform particle growth, and increase tap density. Sodium sorbate ensures a stable chemical environment for prolonged reactions.

[0030] In some optional embodiments, the ratio of the mixed salt solution to the additive can be 1L:(1g~5g), such as 1L:1g, 1L:2g, 1L:3g, 1L:4g, or 1L:5g, or other values ​​within the range of 1L:(1g~5g). In some more typical embodiments, the ratio of the mixed salt solution to the additive can be 1L:(2g~4g).

[0031] If the amount of additive is too small, it can easily lead to impure precursor phases and irregular particle morphology; if the amount of additive is too large, it can easily increase production costs and make it difficult for particles to form the required morphology.

[0032] In some optional embodiments, the raw material salt in the raw material salt solution includes soluble iron salt, soluble molybdenum salt, and soluble tellurium salt. The addition of Fe, Mo, and Te can improve the crystal structure, electronic conductivity, and chemical stability of the precursor. Fe can dissolve into the crystal lattice, relieving cyclic stress, improving structural stability, and reducing raw material costs. Mo can improve electronic conductivity and form strong Mo-O bonds, suppressing oxygen release under high voltage and improving thermal stability. Te can regulate the primary particles to a slender morphology, releasing stress, and can also increase interlayer spacing, constructing rapid ion transport channels.

[0033] The amounts of the aforementioned soluble iron salt, soluble molybdenum salt, and soluble tellurium salt can be set as follows: In the nickel-manganese binary precursor, Fe atoms account for 1% to 5% of the total metal moles, Mo atoms account for 0.1% to 1% of the total metal moles, and Te atoms account for 0.1% to 1% of the total metal moles.

[0034] The Fe doping amount can be 1% to 5%, such as 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, or 5%, or other values ​​within the range of 1% to 5%. The Mo doping amount can be 0.1% to 1%, such as 0.1%, 0.2%, 0.5%, 0.8%, or 1%, or other values ​​within the range of 0.1% to 1%. The Te doping amount can be 0.1% to 1%, such as 0.1%, 0.2%, 0.5%, 0.8%, or 1%, or other values ​​within the range of 0.1% to 1%.

[0035] In some typical implementations, in the nickel-manganese binary precursor, Fe atoms account for 2% to 4% of the total metal moles, Mo atoms account for 0.1% to 0.3% of the total metal moles, and Te atoms account for 0.1% to 0.4% of the total metal moles.

[0036] In some optional embodiments, the coprecipitation reaction is carried out at a temperature of 40°C to 80°C, a pH of 8.5 to 12.0, and a time of 50 to 100 hours. The stirring speed during the process can be 600 to 800 rpm.

[0037] The temperature of the coprecipitation reaction can be 40℃, 45℃, 50℃, 55℃, 60℃, 65℃, 70℃, 75℃ or 80℃, or other values ​​within the range of 40℃ to 80℃.

[0038] The pH value for the coprecipitation reaction can be 8.5, 9.0, 9.5, 10.0, 10.5, 11.0, 11.5 or 12.0, or other values ​​within the range of 8.5 to 12.0.

[0039] The coprecipitation reaction time can be 50h, 55h, 60h, 65h, 70h, 75h, 80h, 85h, 90h, 95h or 100h, or other values ​​within the range of 50h to 100h.

[0040] In some typical implementations, the coprecipitation reaction is carried out at a temperature of 45°C to 60°C and a pH value of 10.5 to 11.5.

[0041] Accordingly, the present invention also provides a nickel-manganese binary precursor, which is prepared by the above-described preparation method.

[0042] In some optional embodiments, the particle size of the nickel-manganese binary precursor is 3μm to 8μm, such as 3.5μm to 5.5μm.

[0043] In some alternative embodiments, the tap density of the nickel-manganese binary precursor is ≥1.2 g / cm³. 3 For example, it can be 1.30 g / cm³ 3 ~1.67g / cm 3 .

[0044] In some optional embodiments, the specific surface area of ​​the nickel-manganese binary precursor is 5 m². 2 / g~25m 2 / g, such as 12.1m 2 / g~24.5m 2 / g.

[0045] In some optional embodiments, the nickel-manganese binary precursor is in the form of a thick sheet-like intercalation structure. The sheet thickness of the nickel-manganese binary precursor can be 200nm~600nm, such as 200nm, 300nm, 400nm, 500nm or 600nm, or other values ​​within the range of 200nm~600nm.

[0046] In addition, the present invention also provides a cathode material obtained by sintering the above-mentioned nickel-manganese binary precursor with a lithium source.

[0047] In some alternative embodiments, the cathode material can be a high-voltage spinel structure lithium nickel manganese oxide cathode material or a lithium-rich manganese-based cathode material.

[0048] In addition, the present invention also provides a battery comprising the above-mentioned positive electrode material.

[0049] In some alternative embodiments, the positive electrode material of the battery is a spinel-structured lithium nickel manganese oxide positive electrode material obtained by further preparation of a nickel-manganese binary precursor.

[0050] The battery's first charge capacity is no less than 155.3 mAh / g, and can be between 155.39 mAh / g and 156.80 mAh / g.

[0051] The battery's first discharge specific capacity is no less than 134.5 mAh / g, such as 134.54 mAh / g to 135.49 mAh / g.

[0052] The initial coulombic efficiency of the battery is no less than 86.2%, and can be 86.29% to 86.58%.

[0053] The battery retains a rate of no less than 96.5% after 500 cycles, and can be 96.5% to 97.0%.

[0054] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0055] Example 1 This embodiment provides a nickel-manganese binary precursor, the preparation method of which is as follows: S1: Prepare the solution.

[0056] Mixed metal salt solution: obtained by dissolving nickel sulfate and manganese sulfate in water, with a molar ratio of Ni:Mn = 0.3:0.7.

[0057] Precipitating agent: 10 mol / L sodium hydroxide aqueous solution.

[0058] Complexing agent: Ammonia solution with a concentration of 9 mol / L.

[0059] Additive solution: Sodium isoascorbate, tea polyphenols, sodium tartrate and sodium sorbate are mixed in a mass ratio of 1:1:1:1 and dissolved in water. The total concentration of additives in the additive solution is 10 g / L.

[0060] Raw material salt solutions: ferrous sulfate was prepared into a 1.0 mol / L solution using sulfuric acid, sodium molybdate was prepared into a 0.1 mol / L solution using deionized water, and tellurium dioxide was prepared into a 0.1 mol / L solution using NaOH solution.

[0061] S2: Prepare the base solution.

[0062] Add 1 / 3 of the effective volume of pure water to the reactor, purge with nitrogen to replace air, turn on stirring and heating, stirring speed is 800 rpm, reactor temperature is 50℃, add complexing solution and precipitation solution, the concentration of complexed ions in the bottom solution is 0.3 mol / L, and adjust the pH of the bottom solution to 11.5.

[0063] S3: Coprecipitation reaction.

[0064] A mixed metal salt solution, a precipitant (to adjust the pH), a complexing agent, an additive solution, and a raw material salt solution are introduced concurrently into the base liquid. By adjusting the flow rate, the proportions of Fe atoms to the total metal moles are controlled to be 4%, Mo atoms to the total metal moles to the total metal moles to the total metal moles to the total metal moles to the total metal moles to the total metal moles to the total metal moles to the total metal moles to the total metal moles to the total metal moles. The ratio of the mixed salt solution to the additive is 1L:3g. The reaction is carried out under the conditions of stirring speed of 800rpm, temperature of 50℃, pH value of 11.5, and ammonia content in the reaction slurry of 0.3mol / L until the particle size reaches the target particle size (5.5μm).

[0065] S4: Post-processing.

[0066] The precursor slurry obtained after the co-precipitation reaction was dehydrated. The resulting filter cake was washed by centrifugation with 3 times its weight of alkaline solution, and then washed several times by centrifugation with 3 times its weight of deionized water. After the content of various impurities met the standards, the filter cake was dehydrated by centrifugation and then dried at 120℃ for 20 h to obtain the nickel-manganese binary precursor. Its SEM image is shown below. Figure 1 As shown.

[0067] Example 2 This embodiment provides a nickel-manganese binary precursor, the preparation method of which is as follows: S1: Prepare the solution.

[0068] Mixed metal salt solution: obtained by dissolving nickel sulfate and manganese sulfate in water, with a molar ratio of Ni:Mn = 0.25:0.75.

[0069] Precipitant: A 5 mol / L aqueous solution of sodium hydroxide.

[0070] Complexing agent: Ammonia solution with a concentration of 6 mol / L.

[0071] Additive solution: Sodium isoascorbate, tea polyphenols, sodium tartrate and sodium sorbate are mixed in water at a mass ratio of 1:2:1:2 and dissolved in water. The total concentration of additives in the additive solution is 10 g / L.

[0072] Raw material salt solution: Same as in Example 1.

[0073] S2: Prepare the base solution.

[0074] Add 1 / 3 of the effective volume of pure water to the reactor, purge with nitrogen to replace air, turn on stirring and heating, with a stirring speed of 600 rpm and an internal temperature of 45°C. Add complexing solution and precipitation solution, with a bottom solution complex ion concentration of 0.2 mol / L, and adjust the pH of the bottom solution to 10.5.

[0075] S3: Coprecipitation reaction.

[0076] A mixed metal salt solution, a precipitant (to adjust the pH), a complexing agent, an additive solution, and a raw material salt solution are introduced concurrently into the bottom liquid. By adjusting the flow rate, the proportions of Fe atoms to the total metal moles are controlled to be 2%, Mo atoms to the total metal moles to be 0.2%, and Te atoms to the total metal moles to be 0.4%. The ratio of the mixed salt solution to the additive is 1L:2g. The reaction is carried out under the conditions of a stirring speed of 600rpm, a temperature of 45℃, a pH of 10.5, and an ammonia content of 0.2mol / L in the reaction slurry until the particle size reaches the target particle size (4.0μm).

[0077] S4: Post-processing.

[0078] The precursor slurry obtained after coprecipitation reaction was dehydrated, and the resulting filter cake was washed by centrifugation with 3 times its weight of alkaline solution, and then washed by centrifugation several times with 3 times its weight of deionized water. After the content of various impurities met the standard, the filter cake was dehydrated by centrifugation and then dried at 120℃ for 20h to obtain the nickel-manganese binary precursor.

[0079] Example 3 This embodiment provides a nickel-manganese binary precursor, the preparation method of which is as follows: S1: Prepare the solution.

[0080] Mixed metal salt solution: obtained by dissolving nickel sulfate and manganese sulfate in water, with a molar ratio of Ni:Mn = 0.2:0.8.

[0081] Precipitating agent: 10 mol / L sodium hydroxide aqueous solution.

[0082] Complexing agent: Ammonia solution with a concentration of 9 mol / L.

[0083] Additive solution: Sodium isoascorbate, tea polyphenols, sodium tartrate and sodium sorbate are mixed in water at a mass ratio of 2:1:3:1 and dissolved in water. The total concentration of additives in the additive solution is 10 g / L.

[0084] Raw material salt solution: Same as in Example 1.

[0085] S2: Prepare the base solution.

[0086] Add 1 / 3 of the effective volume of pure water to the reactor, purge with nitrogen for air replacement, turn on stirring and heating, with a stirring speed of 750 rpm and an internal temperature of 60°C. Add complexing solution and precipitation solution, with a bottom solution complex ion concentration of 0.1 mol / L, and adjust the pH of the bottom solution to 10.8.

[0087] S3: Coprecipitation reaction.

[0088] A mixed metal salt solution, a precipitant (to adjust the pH), a complexing agent, an additive solution, and a raw material salt solution are introduced concurrently into the base liquid. By adjusting the flow rate, the proportions of Fe atoms to the total metal moles are controlled to be 4%, Mo atoms to the total metal moles to be 0.1%, and Te atoms to the total metal moles to be 0.1%. The ratio of the mixed salt solution to the additive is 1L:4g. The reaction is carried out under the conditions of a stirring speed of 750rpm, a temperature of 60℃, a pH of 10.8, and an ammonia content of 0.1mol / L in the reaction slurry until the particle size reaches the target particle size (3.5μm).

[0089] S4: Post-processing.

[0090] The precursor slurry obtained after coprecipitation reaction was dehydrated, and the resulting filter cake was washed by centrifugation with 3 times its weight of alkaline solution, and then washed by centrifugation several times with 3 times its weight of deionized water. After the content of various impurities met the standard, the filter cake was dehydrated by centrifugation and then dried at 120℃ for 20h to obtain the nickel-manganese binary precursor.

[0091] Comparative Example 1 The difference between this comparative example and Example 1 is that no additive solution or doped raw material salt solution was used.

[0092] Comparative Example 2 The difference between this comparative example and Example 1 is that no additive solution was used.

[0093] Comparative Example 3 The difference between this comparative example and Example 1 is that no doped raw material salt solution was used.

[0094] Comparative Example 4 The difference between this comparative example and Example 1 is that the ratio of the mixed salt solution to the additive is 1L: 5.5g.

[0095] Comparative Example 5 The difference between this comparative example and Example 1 is that the total amount of the raw material salt solution remains unchanged, and the doped raw material salt contains only soluble molybdenum salt.

[0096] Comparative Example 6 The difference between this comparative example and Example 1 is that the total amount of the raw material salt solution remains unchanged, and the doped raw material salt contains only soluble iron salt.

[0097] Comparative Example 7 The difference between this comparative example and Example 1 is that the total amount of the raw material salt solution remains unchanged, and the doped raw material salt contains only soluble tellurium salt.

[0098] Comparative Example 8 The difference between this comparative example and Example 1 is that in the nickel-manganese binary precursor, Fe atoms account for 5.5% of the total metal moles.

[0099] Comparative Example 9 The difference between this comparative example and Example 1 is that in the nickel-manganese binary precursor, Mo atoms account for 1.5% of the total number of metal moles.

[0100] Comparative Example 10 The difference between this comparative example and Example 1 is that in the nickel-manganese binary precursor, Te atoms account for 1.5% of the total metal moles.

[0101] Test case (1) The precursor materials obtained in Examples 1-3 and Comparative Examples 1-10 were subjected to the following tests, and the results are shown in Table 1.

[0102] The particle size was tested in accordance with GB / T 19077-2024; The tap density was tested in accordance with GB / T5162-2021; The specific surface area was tested in accordance with GB / T 19587-2017.

[0103] Table 1 Test Results

[0104] (2) The precursor materials obtained in Examples 1-3 and Comparative Examples 1-10 were prepared into spinel structure lithium nickel manganese oxide cathode materials according to the following methods, and then batteries were prepared for performance testing.

[0105] Preparation method of spinel structure lithium nickel manganese oxide cathode material: The nickel-manganese binary precursor is pre-calcined at 600℃ for 5h in an oxygen atmosphere with a molar ratio of total metal element to lithium element in lithium source (lithium carbonate) of 1:1.06, and then sintered at 800℃ for 20h. After that, it is taken out, ground and pulverized to obtain spinel structure lithium nickel manganese oxide cathode material.

[0106] Battery preparation: Spinel-structured lithium nickel manganese oxide positive electrode material, carbon black, and PVDF are mixed in a mass ratio of 8:1:1 to form a positive electrode sheet; the positive electrode sheet, separator, and negative electrode sheet (lithium metal sheet) are stacked in sequence and injected with electrolyte (such as 1 mol / L LiPF6 dissolved in a mixed solvent of EC and DMC) and encapsulated into a battery.

[0107] The assembled battery underwent its first charge-discharge test, activating the electrodes at a 1C rate. Subsequent electrochemical performance tests, including cycle and rate tests, were performed, and the results are shown in Table 2.

[0108] Table 2 Test Results

[0109] As can be seen from Table 2, the nickel-manganese binary precursors prepared in Examples 1-3 can further obtain batteries with better overall electrochemical performance compared with Comparative Examples 1-10.

[0110] In summary, this invention, through the addition of specific amounts of sodium isoascorbate, tea polyphenols, sodium tartrate, and sodium sorbate as additives during the co-precipitation process, can improve the morphology, structure, and particle size distribution of the precursor particles and prevent Mn oxidation. The addition of specific amounts of Fe, Mo, and Te doping ions helps to expand the ion diffusion channels of the cathode material, promote ion diffusion and migration, and improve the rate performance of the cathode material; on the other hand, it can suppress lattice distortion and improve structural stability. Furthermore, doping with high-valence metals can strengthen the MO bonds, stabilize the lattice structure, and further improve the structural stability of the cathode material. The nickel-manganese binary precursor provided by this invention can be used to prepare high-voltage spinel-structured lithium nickel manganese oxide cathode materials and lithium-rich manganese-based cathode materials, exhibiting excellent electrochemical performance.

[0111] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a nickel-manganese binary precursor, characterized in that, Includes the following steps: A co-precipitation reaction is carried out by adding a mixed metal salt solution, precipitant, complexing agent, additive solution, and raw material salt solution to the bottom liquid in parallel flow until the preset particle size is obtained; the material obtained from the reaction is then subjected to solid-liquid separation, washing, and drying. The mixed metal salt solution is a mixed salt solution of soluble nickel salt and soluble manganese salt; the precipitant is sodium hydroxide solution; the complexing agent is ammonia water; the additives in the additive solution include sodium isoascorbate, tea polyphenols, sodium tartrate, and sodium sorbate; the raw material salts in the raw material salt solution include soluble iron salt, soluble molybdenum salt, and soluble tellurium salt. The coprecipitation reaction was carried out at a temperature of 40℃~80℃, a pH of 8.5~12.0, and a time of 50h~100h.

2. The preparation method according to claim 1, characterized in that, The total concentration of Ni and Mn in the mixed salt solution is 0.1 mol / L to 2.5 mol / L; Ni:Mn=x:(1-x), 0.1≤x≤0.

5.

3. The preparation method according to claim 1, characterized in that, The concentration of the sodium hydroxide solution is 5 mol / L to 15 mol / L.

4. The preparation method according to claim 1, characterized in that, The concentration of the complexing agent is 5 mol / L to 10 mol / L, and the ammonia content in the reaction slurry is controlled to be 0.1 mol / L to 1.0 mol / L.

5. The preparation method according to claim 1, characterized in that, The ratio of the mixed salt solution to the additive is 1L:(1g~5g); In the additive, the mass ratio of sodium isoascorbate, tea polyphenols, sodium tartrate and sodium sorbate is (1~5):(1~5):(1~5):(1~5).

6. The preparation method according to claim 1, characterized in that, The amounts of the soluble iron salt, the soluble molybdenum salt, and the soluble tellurium salt are set as follows: In the nickel-manganese binary precursor, Fe atoms account for 1% to 5% of the total metal moles, Mo atoms account for 0.1% to 1% of the total metal moles, and Te atoms account for 0.1% to 1% of the total metal moles.

7. A nickel-manganese binary precursor, characterized in that, It is prepared by the preparation method according to any one of claims 1 to 6.

8. The nickel-manganese binary precursor according to claim 7, characterized in that, The nickel-manganese binary precursor has at least one of the following characteristics: Feature 1: The particle size of the nickel-manganese binary precursor is 3μm~8μm; Feature 2: The tap density of the nickel-manganese binary precursor is ≥1.2 g / cm³. 3 ; Feature 3: The specific surface area of ​​the nickel-manganese binary precursor is 5m². 2 / g~25m 2 / g; feature 4: The nickel-manganese binary precursor has a thick-plate insert structure; Preferably, the thickness of the nickel-manganese binary precursor is 200nm~600nm.

9. A positive electrode material, characterized in that, It is obtained by sintering the nickel-manganese binary precursor as described in claim 7 or 8 with a lithium source.

10. A battery, characterized in that, Includes the cathode material as described in claim 9.

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