Production and preparation process of manganous-manganic oxide material for battery

Abstract

The invention relates to the technical field of preparation of manganous-manganic oxide, in particular to a production and preparation process of a manganous-manganic oxide material for batteries, which comprises the following steps: dissolving high-purity manganese sulfate to prepare a manganese sulfate solution, and adding a dispersing agent and a surfactant to obtain a manganese salt solution; the method comprises the following steps: adding a base solution into a reaction kettle, stirring and heating, conveying a manganese salt solution and ammonia water, synchronously introducing oxygen, dividing the whole oxidation reaction process into two stages, controlling the flow velocity of the ammonia water in different stages, and dynamically adjusting the temperature; and carrying out suspension precipitation on manganous-manganic oxide obtained by the oxidation reaction, aging, and carrying out dehydration suction filtration, washing and drying to obtain the manganous-manganic oxide material for the battery. The invention aims to adjust the morphology of the manganous-manganic oxide finished product by controlling reaction conditions, effectively reduce the granularity of the product and enhance the uniformity of particle size distribution.

Description

Technical Field

[0001] The present application relates to the technical field of manganese tetraoxide preparation, and in particular to a production process for manganese tetraoxide materials for batteries. Background Art

[0002] In the field of new energy, manganese tetraoxide ( )yes Compared with electrolytic manganese dioxide (EMD), the precursor has the characteristics of high manganese atom utilization, good structural stability, low cost and spinel structure matching. It can effectively solve the problem of battery discharge capacity attenuation and is urgently needed in the preparation of high-quality lithium-ion batteries.

[0003] The existing production and preparation processes of manganese tetraoxide materials include the roasting method, which is prepared by high-temperature decomposition of manganese sulfate. However, due to the high calcium and magnesium impurity content, the product particles are large, the physical properties are poor, and the exhaust gas containing SOx pollutes the environment; the metal manganese suspension oxidation method requires the electrolysis of metal manganese sheets, which is costly and difficult to control impurities; the manganese salt precipitation oxidation method has a relatively wide source of raw materials, but requires the use of inert gas for protection, the process flow is relatively complex, and the product morphology is difficult to control. Summary of the Invention

[0004] In view of the above, it is necessary to provide a production process for manganese manganese oxide material for batteries to solve the above problems.

[0005] One embodiment of the present application provides a production process for a manganese manganese oxide material for a battery, the process comprising: Manganese sulfate is dissolved to prepare a manganese sulfate solution, and a dispersant and a surfactant are added to obtain a manganese salt solution; a base liquid is added to a reactor, stirred and heated, and the manganese salt solution and ammonia water are supplied, and oxygen is introduced simultaneously, dividing the entire oxidation reaction process into two stages, and controlling the flow rate of the ammonia water in different stages; Preset a reaction stabilization period during the reaction process, and obtain the oxygen concentration, pH, and temperature at each sampling moment in each reaction stabilization period; based on the degree of difference in pH distribution between the reaction stabilization period at each sampling moment and the previous reaction stabilization period, combined with the distribution of oxygen concentration within the preset window at each sampling moment, determine the intensity of the manganese salt oxidation reaction at each sampling moment; The similarity measure between the manganese salt oxidation reaction intensity and temperature at all sampling moments in each reaction stabilization period is analyzed, and combined with the distribution of the manganese salt oxidation reaction intensity predicted for the next reaction stabilization period, the temperature rise characteristic value of the reaction solution in each reaction stabilization period is obtained. Preset the reaction standard temperature for the first stage, analyze the difference between the temperature at each sampling moment of each reaction stabilization period in the first stage and the reaction standard temperature, and obtain the supersaturation reduction evaluation value for each reaction stabilization period; The negative control intensity is obtained through the temperature rise characteristic value of the reaction solution and the supersaturation decrease evaluation value of each reaction stabilization cycle, and the temperature is controlled in the next reaction stabilization cycle; The manganese tetraoxide obtained by the oxidation reaction is suspended and precipitated, and then aged, and the manganese tetraoxide material for the battery is obtained after dehydration, filtration, washing and drying.

[0006] Wherein, the concentration of the prepared manganese sulfate solution is 1-2 mol / L.

[0007] Among them, the addition amount of the dispersant is 1~2.5g / L, and the addition amount of the surfactant is 1~5g / L; among them, the dispersant is specifically any one of sodium lauryl sulfate, polyethylene glycol, dichloroethane, and sodium tartrate, or a combination of at least two thereof, and the surfactant is specifically any one of stearic acid, sodium dioctyl succinate, and sodium dodecylbenzenesulfonate, or a combination of at least two thereof.

[0008] The specific operation of the stirring and heating is to heat the bottom water temperature of the reactor to 50-60°C and stir at a speed of 300-500 rpm.

[0009] Among them, the specific operation of conveying manganese salt solution and ammonia water is as follows: the dosage of manganese salt solution and ammonia water is 3m³ and 3.8m³ respectively, and the volume ratio of base liquid to manganese salt solution is controlled at (0.5:1)~(1:1); the flow rate of ammonia water in different stages is specifically controlled as follows: the flow rate of ammonia water in the preset first stage of the oxidation reaction is 1.2~1.5L / min, and the flow rate of ammonia water in the preset second stage of the reaction is 6.5~6.8L / min.

[0010] Wherein, the determination of the intensity of the manganese salt oxidation reaction at each sampling moment includes: The mean pH value of the previous stable reaction period of the stable reaction period at each sampling moment is obtained, and the difference between the pH value at each sampling moment and the mean pH value is calculated and recorded as the reaction factor; the negative correlation mapping result of the oxygen concentration characteristic value at each sampling moment is calculated and multiplied by the reaction factor to obtain the manganese salt oxidation reaction intensity at each sampling moment.

[0011] The temperature rise characteristic value of the reaction solution in each stable reaction period is obtained as follows: The sequence of the intensity components of the manganese salt oxidation reaction and the sequence of the temperature components at all sampling moments in each reaction stability period are recorded as the reaction intensity sequence and the temperature sequence respectively; The similarity measure between the temperature series and the reaction intensity series of each reaction stability period is used as the temperature rise weight of the manganese salt oxidation reaction; The element mean of the reaction intensity sequence is recorded as the first mean; the reaction intensity sequence is used as the input of the prediction algorithm to obtain the reaction intensity prediction sequence of the next reaction stability period, and the element mean of the reaction intensity prediction sequence is calculated and recorded as the second mean; The difference between the second mean and the first mean is calculated as a reaction intensity deviation value; and the result of forward fusion of the reaction intensity difference and the temperature weight is used as a temperature rise characteristic value of the reaction solution.

[0012] The supersaturation reduction evaluation value obtained in each reaction stabilization cycle is specifically: Calculate the difference between the temperature at each sampling moment during the reaction stabilization period and the reaction standard temperature, and divide it by the reaction standard temperature to obtain the coefficient of variation at each sampling moment; The mean of the coefficient of variation at all sampling moments within the reaction stability period was taken as the supersaturation decrease evaluation value.

[0013] The specific process of obtaining the negative control intensity and performing temperature control on the next reaction stabilization period is as follows: For each stable reaction cycle, the normalized value of the reaction solution temperature rise characteristic value and the supersaturation decrease evaluation value is calculated and fused as the negative control intensity; the element mean of the temperature sequence of each stable reaction cycle is calculated and recorded as the first temperature value; When the next reaction temperature cycle of each reaction stabilization cycle is the first stage of the manganese salt oxidation reaction: If the negative control intensity of each reaction temperature cycle is greater than a preset first threshold value, the value obtained by subtracting the preset temperature from the first temperature value is used as the preset reaction temperature value of the reactor in the next reaction stabilization cycle; if the negative control intensity of each reaction temperature cycle is less than a preset second threshold value, the value obtained by adding the preset temperature to the first temperature value is used as the preset reaction temperature value of the reactor in the next reaction stabilization cycle; if the negative control intensity of each reaction temperature cycle is between the first threshold value and the second threshold value, the first temperature value is used as the preset reaction temperature value of the reactor in the next reaction stabilization cycle; wherein the first threshold value is greater than the second threshold value; When the next reaction temperature period of each reaction stabilization period is the second stage of the manganese salt oxidation reaction, a fixed reaction temperature preset value is adopted.

[0014] The dehydration, filtration and washing are repeated no less than 3 times.

[0015] The beneficial effects of this application are: 1. This application adopts the manganese salt primary oxidation method, eliminating the need for The precipitation step adjusts the finished morphology of manganese oxide by controlling the reaction conditions, which is conducive to obtaining granular, spherical and other morphological products with different needs, and improves its adaptability in application scenarios such as lithium-ion batteries.

[0016] 2. This application controls the ammonia flow rate and reaction temperature in stages to promote the nucleation of manganese dioxide in large quantities in the first stage and uniform growth in the second stage, effectively reducing the product particle size and enhancing the uniformity of the particle size distribution. The product particle size distribution is more concentrated, thereby improving the rate performance in the electrochemical performance.

[0017] 3. This application takes into account the exothermic phenomenon of the manganese salt oxidation reaction process to avoid the exothermic reaction in the first stage. Supersaturation is greatly reduced, ensuring In the first stage of crystallization, a large number of nuclei are formed, which effectively controls Crystal nucleation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a flow chart of a production process for a manganese manganate material for batteries provided in this application; Figure 2 This is a flow chart of temperature control during the oxidation reaction process provided in this application. DETAILED DESCRIPTION

[0019] In the description of the embodiments of this application, words such as "exemplary," "or," and "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of this application should not be construed as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary," "or," and "for example" is intended to present the relevant concepts in a concrete manner.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art in the art of this application. The terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0021] It should also be noted that the terms "first" and "second" in this application and its accompanying drawings are used to distinguish similar objects, rather than to describe a specific order or precedence. The methods disclosed in the embodiments of this application or the methods shown in the flowcharts include one or more steps for implementing the methods. Without departing from the scope of protection of this application, the order of execution of multiple steps can be interchanged with each other, and some steps can also be deleted.

[0022] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0023] The present invention adopts a manganese salt primary oxidation method to prepare manganese tetraoxide for battery. Specifically, an oxidant is introduced into a manganese salt solution to make , directly oxidized to The reaction equation for the preparation of manganese salt by the primary oxidation method is: Compared with the manganese salt precipitation oxidation method, the manganese salt primary oxidation method saves The precipitation step reduces the preparation process steps of manganese tetraoxide, and the morphology of the finished product of manganese tetraoxide can be adjusted by controlling the reaction conditions.

[0024] The present invention provides a production process for a manganese tetraoxide material for a battery, which is applied to the technical field of manganese tetraoxide preparation. Figure 1 The process includes: raw material preparation, synthesis, washing, drying and packaging.

[0025] S1: Raw material preparation S101: High-purity manganese sulfate ( ) is dissolved in deionized water to prepare a 1-2 mol / L manganese sulfate solution in a batching tank. A dispersant and surfactant are then added to eliminate agglomeration and inhibit manganese ion hydrolysis, thereby better controlling the particle size and micromorphology of the manganese tetraoxide product and obtaining a manganese salt solution. The dispersant is added in an amount of 1-2.5 g / L, and the surfactant in an amount of 1-5 g / L.

[0026] The concentration of the manganese sulfate solution in Example 1 is 1.25 mol / L, the concentration of the manganese sulfate solution in Example 2 is 1 mol / L; and the concentration in Example 3 is 2 mol / L.

[0027] In Example 1, the dispersant is a mixture of sodium lauryl sulfate and polyethylene glycol, and the addition amount is 1 g / L, and the surfactant is a mixture of stearic acid and dioctyl sodium sulfosuccinate, and the addition amount is 4 g / L; in Example 2, the dispersant is ethylene dichloride, and the addition amount is 2 g / L, and the surfactant is a mixture of dioctyl sodium sulfosuccinate and sodium dodecylbenzenesulfonate, and the addition amount is 5 g / L; in Example 3, the dispersant is a mixture of polyethylene glycol, dichloroethane and sodium tartrate, and the addition amount is 2.5 g / L, and the surfactant is stearic acid, and the addition amount is 1 g / L.

[0028] S102: Store 2 mol / L ammonia solution in a clean, sealed tank that meets safety standards.

[0029] S103: Adding a bottom liquid, specifically deionized water, into the reactor, and starting the reactor stirring device and heating device to adjust the bottom water temperature of the reactor to 50-60° C. and the stirring speed to 300-500 rpm.

[0030] In Example 1, the temperature of the water at the bottom of the reactor reached 50°C and the stirring speed was 500 rpm; in Example 2, the temperature of the water at the bottom of the reactor reached 50°C and the stirring speed was 350 rpm; in Example 3, the temperature of the water at the bottom of the reactor reached 60°C and the stirring speed was 300 rpm.

[0031] S2: Synthesis The manganese salt solution from the batching tank and the ammonia solution from the storage tank are transported to the reactor via a closed piping system. The manganese salt solution dosage is 3 m³, and the volume ratio of the base liquid to the manganese salt solution is controlled between (0.5:1) and (1:1). Increasing the ammonia-manganese molar ratio improves the surface smoothness of the manganese oxide particles, which helps further reduce the specific surface area. However, an excessively high ammonia-manganese molar ratio increases the reagent dosage. In this application, the total amount of ammonia solution is selected to be 3.8 m³.

[0032] In Example 1, the volume ratio of the base liquid to the manganese salt solution is controlled at 0.5:1; in Example 2, the volume ratio of the base liquid to the manganese salt solution is controlled at 0.8:1; in Example 3, the volume ratio of the base liquid to the manganese salt solution is controlled at 1:1.

[0033] Oxygen is introduced into the reactor as an oxidant to react, and the temperature control method is used to dynamically adjust the reaction temperature of the reactor to avoid excessive temperature in the first stage of the reaction, greatly increase the supersaturation of the system, and at the same time minimize the fluctuation of the reaction temperature to effectively control Crystal nucleation process. During the entire reaction process, the reaction time was 12 hours, and the reactor speed was controlled to be 800-950 r / min. The speed was 900 r / min in Example 1, 800 r / min in Example 2, and 950 r / min in Example 3. The higher speed allowed for faster diffusion and more uniform distribution of the solute in the solution, alleviating the problem of different secondary particle growth rates caused by concentration differences at different locations.

[0034] Without changing the total amount of ammonia used, the reaction time is divided into two stages, the ammonia flow rate in the first stage is reduced, and the complexing capacity of the system is reduced, in order to promote the first stage of the reaction. A large number of nuclei are formed to inhibit the growth of grains; wherein, the first stage is specifically the first 3 hours of the reaction; increasing the flow rate of ammonia water in the second stage is to reduce the supersaturation of the system and promote Continue to grow on the crystal nucleus formed in the first stage, reducing Product granularity, enhanced The uniformity of particle size distribution improves Firing as a precursor The rate performance of the positive electrode material; wherein, the second stage is specifically the last 9 hours of the reaction.

[0035] Specifically, in the production and preparation process of manganese tetraoxide, a metering pump is used to control the opening and closing of the reactor valve and the start and stop of the pipeline system pump in a chain manner according to the total amount of ammonia water to prevent excessive delivery of ammonia water and control the speed of ammonia addition. In the first stage of the reaction, the ammonia water flow rate is 1.2~1.5L / min, and in the second stage of the reaction, the ammonia water flow rate is 6.5~6.8L / min.

[0036] In Example 1, the ammonia flow rate in the first stage of the reaction is 1.4 L / min, and the ammonia flow rate in the second stage of the reaction is 6.6 L / min; in Example 2, the ammonia flow rate in the first stage of the reaction is 1.2 L / min, and the ammonia flow rate in the second stage of the reaction is 6.5 L / min; in Example 3, the ammonia flow rate in the first stage of the reaction is 1.5 L / min, and the ammonia flow rate in the second stage of the reaction is 6.8 L / min.

[0037] The manganese tetraoxide suspension precipitate after the reaction was transferred to an aging kettle for aging for 4 hours.

[0038] S3: Washing In Example 1, the aged manganese tetraoxide suspension was repeatedly dehydrated, filtered and washed three times by a centrifuge to obtain a cake; in Example 2, the dehydration, filtration and washing were repeated four times; in Example 3, the dehydration, filtration and washing were repeated five times.

[0039] S4: Drying The washed cake is added to the flash evaporator for drying to obtain product.

[0040] S5: Packaging The dried powder is transferred to a mixer and stirred for 30-60 minutes to prevent localized compositional inconsistencies that could affect product quality. A vibrating screen then removes agglomerated particles, and a permanent magnetic separator removes magnetic impurities, further improving product purity and quality stability. Finally, an automatic weighing system is used to unload and package the powder according to specifications (e.g., 25 kg / bag). The packaging must be labeled with the product name, batch number, specifications, and production date.

[0041] In order to overcome the shortcomings of the prior art, the present application proposes a staged temperature control method in the synthesis process of a production process of manganese tetraoxide for batteries, so as to solve the problem that the first stage of the manganese salt primary oxidation reaction requires a higher supersaturation, so that Crystallization is more inclined to nucleation, but the oxidation reaction of manganese salt is an exothermic reaction, which causes the reaction temperature to rise, and the temperature stability is poor, making it difficult to effectively control. The crystal nucleation process leads to The problem of uneven product particle size distribution.

[0042] Step 1: Preset a reaction stabilization period during the reaction process and obtain the oxygen concentration, pH, and temperature at each sampling moment in each reaction stabilization period.

[0043] This application installs an oxygen sensor on the top of the reactor to monitor the oxygen concentration inside the reactor. The motor of an online pH meter is immersed in the reactor solution to measure the pH value of the reactor solution. A thermal resistor temperature sensor is directly inserted into the reactor solution to obtain the temperature value of the reactor solution. The oxygen sensor, online pH meter, and thermal resistor temperature sensor all sample synchronously with a sampling interval of 1 second.

[0044] Because the flow rate of ammonia water is stable within the same stage, the primary oxidation reaction rate of the manganese salt is stable within a short period of time. In this application, the time length T is set as the reaction stabilization period. The time length period T is set to no more than 15 minutes, 5 minutes in this embodiment, and 10 minutes in another embodiment. The oxygen concentration sequence, pH sequence, and temperature sequence of the most recent reaction stabilization period are obtained.

[0045] Step 2: Based on the difference in pH distribution between the reaction stable period at each sampling moment and the previous reaction stable period, combined with the distribution of oxygen concentration in the preset window at each sampling moment, the intensity of the manganese salt oxidation reaction at each sampling moment is determined.

[0046] Manganese salt primary oxidation method, that is, low-cost , oxygen and ammonia as raw materials, and an oxidant is introduced into the manganese salt solution to make Direct oxidation to , which is suitable for large-scale production of manganese tetraoxide. During the primary oxidation reaction of manganese salt, in the early stage of the first stage, the amount of ammonia added is small, the pH of the solution system is low, the oxidation reaction of manganese salt is relatively slow, and because it cannot capture all the oxygen, it causes oxygen to escape to the top layer of the reactor.

[0047] In order to avoid the interference of gas flow in the reactor on concentration detection and improve the detection accuracy of small amounts of gas concentration, this application sets a window, takes the oxygen concentration value at each sampling moment as the center, calculates the mean of all oxygen concentration values in the window, and uses it as the oxygen concentration characteristic value at each sampling moment. The length of the time series window is Obtain the reaction intensity of the manganese salt oxidation reaction at any sampling time Specifically, the following steps are performed: The mean pH value of the reaction stable cycle preceding the reaction stable cycle at each sampling moment is obtained; the difference between the pH value at each sampling moment and the mean pH value is calculated and recorded as a reaction factor; a negative correlation mapping result of the oxygen concentration characteristic value at each sampling moment is calculated and multiplied by the reaction factor to obtain the manganese salt oxidation reaction intensity at each sampling moment. In this embodiment, the negative correlation mapping of the variable is specifically the reciprocal of the variable.

[0048] It should be understood that the reaction factor is used to evaluate the promoting effect of pH on the primary oxidation reaction of manganese salts. The larger the pH value in the first stage, the The easier it is to be oxidized , the higher the intensity of the manganese salt oxidation reaction; the characteristic value of the oxygen concentration at each sampling moment is used to evaluate the degree of oxygen escape from the manganese salt oxidation reaction solution. The higher the oxygen concentration at the top of the reactor, the more difficult it is for the manganese salt oxidation reaction to capture all the oxidants, the manganese salt oxidation reaction may be slower, and the lower the intensity of the manganese salt oxidation reaction.

[0049] Step 3: Analyze the similarity measure between the intensity of the manganese salt oxidation reaction and the temperature at all sampling moments in each reaction stabilization period, and combine it with the distribution of the predicted intensity of the manganese salt oxidation reaction in the next reaction stabilization period to obtain the temperature rise characteristic value of the reaction solution in each reaction stabilization period.

[0050] The oxidation reaction of manganese salt is an exothermic reaction. The higher the reaction intensity, the more heat is released, which has an improving effect on the solution temperature. This application uses the reaction intensity of all sampling moments in the latest reaction stability period to form a reaction intensity sequence; and obtains the temperature sequence of the latest reaction stability period; and uses the similarity measure between the temperature sequence of the latest reaction stability period and the reaction intensity sequence as the temperature rise weight of the manganese salt oxidation reaction. In this embodiment, the Pearson correlation coefficient is used to calculate the similarity measure between the two sequences, which is a statistic used to measure the degree of correlation between the two sequences. The larger the similarity measure, the higher the reaction intensity of the manganese salt primary oxidation reaction, and the more it can cause the solution temperature to rise. Then, a high reaction intensity should have a stronger temperature rise weight.

[0051] In the manganese salt oxidation reaction system, as ammonia water is continuously added, the pH value continues to increase. The easier it is to be oxidized In the first stage, the reaction intensity of the manganese salt oxidation reaction has an increasing trend, and the heat released increases with time. The solution temperature is prone to be too high, reducing the supersaturation of the system.

[0052] This application calculates the element mean of the reaction intensity sequence, which is recorded as the first mean; uses the reaction intensity sequence as the input of the prediction algorithm, obtains the reaction intensity prediction sequence of the next reaction stability period, and calculates the element mean of the reaction intensity prediction sequence, which is recorded as the second mean. Among them, the prediction algorithm can specifically adopt the simple moving average (SMA), weighted moving average (WMA), exponential moving average (EMA), and autoregressive integrated moving average model (ARIMA); calculates the difference between the second mean and the first mean as the reaction intensity deviation value The result of the forward fusion of the reaction intensity difference and the temperature weight is used as the temperature rise characteristic value of the reaction solution; In this embodiment, the temperature rise characteristic value of the reaction solution is recorded as P, and its formula form is: ; Among them, exp() represents the exponential function with a natural constant as the base; Represents the temperature rise weight of the manganese salt oxidation reaction.

[0053] This application is approved To reflect the increasing characteristics of the reaction intensity of the manganese salt oxidation reaction over time, the larger the predicted value of the reaction intensity of the next stable reaction period, the more significant the increasing characteristics. The larger it is, the more heat is released by the enhanced manganese salt oxidation reaction, the more obvious the promoting effect on the temperature increase of the reaction solution is, the higher the temperature increase value of the reaction solution is, and the larger the temperature rise characteristic value of the reaction solution is.

[0054] Step 4: Preset the reaction standard temperature of the first stage, analyze the difference between the temperature at each sampling moment of each reaction stabilization period in the first stage and the reaction standard temperature, and obtain the supersaturation reduction evaluation value of each reaction stabilization period.

[0055] The present invention reduces the flow rate of ammonia water in the first stage of the manganese salt oxidation reaction, reduces the complexation of ammonium ions in the reaction system, and increases the supersaturation of the reaction system. According to the Lamer model of crystal growth, Accelerate nucleation and increase the ammonia flow rate in the second stage to reduce the supersaturation of the reaction system. According to the Lamer model of crystal growth, promote Secondary particle growth.

[0056] The reaction standard temperature of the first stage is set, and in one implementation case, it is 60°C; based on the difference characteristics between the temperature at each sampling moment of the temperature sequence in the latest reaction stabilization period and the reaction standard temperature, the supersaturation decrease evaluation value is obtained, specifically: the difference between the temperature at each sampling moment in the reaction stabilization period and the reaction standard temperature is calculated, and the difference is divided by the reaction standard temperature to obtain the variation coefficient of each sampling moment; the average of the variation coefficients of all sampling moments in the reaction stabilization period is used as the supersaturation decrease evaluation value.

[0057] The oxidation reaction of manganese salt is exothermic, and higher temperature reduces the supersaturation of the system, making The premature tendency is to particle growth, and the supersaturation drop evaluation value is used to evaluate the significance of the supersaturation drop caused by the temperature increase. The larger the supersaturation drop evaluation value, the higher the temperature, resulting in Premature crystallization tends to lead to secondary particle growth, which can easily lead to The product has small particle size and poor uniformity. In the first stage of the manganese salt oxidation reaction, the reaction temperature should be lowered and the supersaturation of the system should be increased.

[0058] Step 5: Obtain the negative control intensity through the temperature rise characteristic value of the reaction solution and the supersaturation decrease evaluation value of each reaction stabilization cycle, and perform temperature control for the next reaction stabilization cycle.

[0059] This application obtains the negative control intensity by using the reaction solution temperature rise characteristic value and the supersaturation drop evaluation value, reflecting the control strength of reducing the temperature value of the manganese salt oxidation reaction. Specifically, in this embodiment, the normalized value after the positive fusion of the reaction solution temperature rise characteristic value and the supersaturation drop evaluation value is calculated as the negative control intensity; the specific formula form is: ; In the formula, Norm[] represents the normalization function; exp() represents the exponential function with the natural constant as the base; P represents the characteristic value of the temperature rise of the reaction solution; G represents the evaluation value of the supersaturation decrease.

[0060] The temperature rise characteristic value of the reaction solution is used to characterize the ability of the reaction solution to increase the temperature due to the increasing intensity of the manganese salt oxidation reaction in the next reaction stability cycle; the supersaturation decrease evaluation value characterizes the effect of the reaction solution temperature increase on the supersaturation of the reaction system. The greater the negative control intensity, the more the reaction temperature value needs to be lowered in the first stage of the manganese salt oxidation reaction to ensure the first stage Crystallization can form a large number of nuclei, reducing The unevenness of the particle size of the finished product.

[0061] The element mean of the temperature sequence within the reaction stability period is used as the first temperature value, and the temperature of the manganese salt oxidation reaction is regulated by the following method, which effectively reduces Product granularity, enhanced The uniformity of particle size distribution improves the rate performance in electrochemical performance: 1) When the next reaction temperature cycle is the first stage of the manganese salt oxidation reaction: i. When the negative control intensity exceeds a preset first threshold, the manganese salt oxidation reaction temperature for the next stable reaction period should be reduced. Specifically, the value obtained by subtracting the preset temperature from the first temperature value is used as the preset reaction temperature for the reactor for the next stable reaction period. Temperature control is then performed using the reactor PI controller during the next stable reaction period. The preset temperature is set to 2, and the first threshold is set to 0.7.

[0062] ii. When the negative control intensity is less than the preset second threshold, it indicates that the temperature increase caused by the reaction intensity during the next stable reaction period is not significant, or even causes a temperature drop. In order to accelerate the manganese salt oxidation reaction, the manganese salt oxidation reaction temperature during the next stable reaction period should be increased. Specifically, the value obtained by adding the preset temperature to the first temperature value is used as the preset reaction temperature value of the reactor during the next stable reaction period, and the temperature is controlled by the reactor PI controller during the next stable reaction period. The second threshold is 0.2.

[0063] iii. When the negative control intensity is between the first threshold and the second threshold, it indicates that the manganese salt oxidation reaction is relatively stable, the reaction temperature fluctuation is poor, and there is no need to adjust the preset value of the reaction temperature of the reactor in the next reaction stabilization period. The temperature is controlled by the reactor PI controller in the next reaction stabilization period.

[0064] 2) When the next reaction temperature cycle is the second stage of the manganese salt oxidation reaction, the second stage goal is to reduce the product The supersaturation of Crystallization tends to promote the growth of secondary particles, increasing The sphericity of the crystallized secondary particles is improved, and the reaction rate of the manganese salt oxidation reaction is increased. Considering the energy consumption of increasing the temperature, this application adopts a fixed reaction temperature preset value in the second stage of the manganese salt oxidation reaction, and the temperature is controlled by the reactor PI controller. Among them, the fixed reaction temperature preset value of the second stage is 70°C in this embodiment.

[0065] Among them, the temperature control flow chart during the oxidation reaction is as follows Figure 2 shown.

[0066] Test results: The method proposed in this application has the advantages of staged temperature control. The finished product is used as an example, and the staged temperature control method proposed in this application will not be used. The finished product was used as a comparative example and the laser particle size analyzer was used to analyze the The particle size distribution of the finished product was measured to obtain a particle size distribution comparison table, as shown in Table 1.

[0067] Will Finished product as precursor mix , fired into Positive electrode materials, and Positive electrode materials, acetylene black and polyvinylidene fluoride (PVDF), according to The mass ratio of 3C to 10C was mixed evenly, N-methylpyrrolidone (NMP) was added to make a slurry, which was coated on aluminum foil and dried in a vacuum drying oven to obtain an electrode. The electrochemical test was carried out using an electrochemical workstation. The electrochemical test specifically included 1C specific capacity, 5C specific capacity, and 10C specific capacity, and the electrochemical performance comparison table was obtained, as shown in Table 2.

[0068] Table 1: Particle size distribution comparison table Table 2: Electrochemical performance comparison The present invention controls the reaction temperature in stages to promote the nucleation of manganese tetraoxide in large quantities in the first stage and the uniform growth in the second stage. The particle size of the finished products is smaller than that of the comparative example, D 50 can reach 4.9 μm, and the embodiment of this application The particle size distribution of the finished product is relatively more concentrated and more uniform. As a precursor, the positive electrode material can provide higher energy output at different charge and discharge rates, and the battery performance is better, which can meet the needs of lithium-ion batteries in high-power application scenarios.

[0069] The flowcharts and block diagrams in the accompanying drawings show the possible architecture, functions and operations of the systems, methods and computer program products according to the embodiments of the present application. In this regard, each box in the flowchart or block diagram can represent a module, a program segment or a part of the code, and the part of the module, program segment or code contains one or more executable instructions for realizing the specified logical function. In some alternative implementations, the functions marked in the box can also occur in an order different from that marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, which can depend on the functions involved. In the description corresponding to the flowcharts and block diagrams in the accompanying drawings, the operations or steps corresponding to different boxes can also occur in an order different from that disclosed in the description, and sometimes there is no specific order between different operations or steps. For example, two consecutive operations or steps can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, which can depend on the functions involved. Each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, may be implemented by a dedicated hardware-based system that performs the specified function or action, or may be implemented by a combination of dedicated hardware and computer instructions.

[0070] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application, and should all be included in the scope of protection of the present application.

Claims

1. A production process for a manganese manganese oxide material for a battery, characterized in that: The process includes: Manganese sulfate is dissolved to prepare a manganese sulfate solution, and a dispersant and a surfactant are added to obtain a manganese salt solution; a base liquid is added to a reactor, stirred and heated, and the manganese salt solution and ammonia water are supplied, and oxygen is introduced simultaneously, dividing the entire oxidation reaction process into two stages, and controlling the flow rate of the ammonia water in different stages; Preset a reaction stabilization period during the reaction process, and obtain the oxygen concentration, pH, and temperature at each sampling moment in each reaction stabilization period; based on the degree of difference in pH distribution between the reaction stabilization period at each sampling moment and the previous reaction stabilization period, combined with the distribution of oxygen concentration within the preset window at each sampling moment, determine the intensity of the manganese salt oxidation reaction at each sampling moment; The similarity measure between the manganese salt oxidation reaction intensity and temperature at all sampling moments in each reaction stabilization period is analyzed, and combined with the distribution of the manganese salt oxidation reaction intensity predicted for the next reaction stabilization period, the temperature rise characteristic value of the reaction solution in each reaction stabilization period is obtained. Preset the reaction standard temperature for the first stage, analyze the difference between the temperature at each sampling moment of each reaction stabilization period in the first stage and the reaction standard temperature, and obtain the supersaturation reduction evaluation value for each reaction stabilization period; The negative control intensity is obtained through the temperature rise characteristic value of the reaction solution and the supersaturation decrease evaluation value of each reaction stabilization cycle, and the temperature is controlled in the next reaction stabilization cycle; The manganese tetraoxide obtained by the oxidation reaction is suspended and precipitated, and then aged, and the manganese tetraoxide material for the battery is obtained after dehydration, filtration, washing and drying.

2. The production process of a manganese manganese oxide material for a battery according to claim 1, characterized in that: The concentration of the prepared manganese sulfate solution is 1-2 mol / L.

3. The production process of a manganese manganic oxide material for a battery according to claim 1, characterized in that: The added amount of the dispersant is 1~2.5g / L, and the added amount of the surfactant is 1~5g / L; wherein, the dispersant is specifically any one of sodium lauryl sulfate, polyethylene glycol, dichloroethane, and sodium tartrate, or a combination of at least two thereof, and the surfactant is specifically any one of stearic acid, sodium dioctyl succinate, and sodium dodecylbenzenesulfonate, or a combination of at least two thereof.

4. The production process of a manganese manganese oxide material for a battery according to claim 1, characterized in that: The specific operation of the stirring and heating is to heat the bottom water temperature of the reactor to 50-60° C. and stir at a speed of 300-500 rpm.

5. The production process of a manganese manganese oxide material for a battery according to claim 1, characterized in that: The specific operation of conveying the manganese salt solution and ammonia water is as follows: the dosage of the manganese salt solution and the ammonia water are 3m³ and 3.8m³ respectively, and the volume ratio of the base liquid to the manganese salt solution is controlled at (0.5:1)~(1:1); the flow rate of the ammonia water in different stages is specifically controlled as follows: the ammonia water flow rate in the preset first stage of the oxidation reaction is 1.2~1.5L / min, and the ammonia water flow rate in the preset second stage of the reaction is 6.5~6.8L / min.

6. The process for producing a manganese manganese oxide material for a battery according to claim 1, wherein: The determination of the intensity of the manganese salt oxidation reaction at each sampling moment includes: The mean pH value of the previous stable reaction period of the stable reaction period at each sampling moment is obtained, and the difference between the pH value at each sampling moment and the mean pH value is calculated and recorded as the reaction factor; the negative correlation mapping result of the oxygen concentration characteristic value at each sampling moment is calculated and multiplied by the reaction factor to obtain the manganese salt oxidation reaction intensity at each sampling moment.

7. The process for producing a manganese manganese oxide material for a battery according to claim 1, wherein: The temperature rise characteristic value of the reaction solution in each stable reaction period is obtained as follows: The sequence of the intensity components of the manganese salt oxidation reaction and the sequence of the temperature components at all sampling moments in each reaction stability period are recorded as the reaction intensity sequence and the temperature sequence respectively; The similarity measure between the temperature series and the reaction intensity series of each reaction stability period is used as the temperature rise weight of the manganese salt oxidation reaction; The element mean of the reaction intensity sequence is recorded as the first mean; the reaction intensity sequence is used as the input of the prediction algorithm to obtain the reaction intensity prediction sequence of the next reaction stability period, and the element mean of the reaction intensity prediction sequence is calculated and recorded as the second mean; Calculating the difference between the second mean and the first mean as a reaction intensity deviation value; The result of forward fusion of the reaction intensity difference and the temperature weight is used as the temperature rise characteristic value of the reaction solution.

8. The process for producing a manganese manganese oxide material for a battery according to claim 1, wherein: The supersaturation reduction evaluation value obtained in each reaction stabilization period is specifically: Calculate the difference between the temperature at each sampling moment during the reaction stabilization period and the reaction standard temperature, and divide it by the reaction standard temperature to obtain the coefficient of variation at each sampling moment; The mean of the coefficient of variation at all sampling moments within the reaction stability period was taken as the supersaturation decrease evaluation value.

9. The process for producing a manganese manganese oxide material for a battery according to claim 7, wherein: The specific process of obtaining the negative control intensity and performing temperature control on the next reaction stabilization period is as follows: For each stable reaction cycle, the normalized value of the temperature rise characteristic value of the reaction solution and the supersaturation decrease evaluation value after positive fusion is calculated as the negative control intensity; the element mean of the temperature sequence of each stable reaction cycle is calculated and recorded as the first temperature value; When the next reaction temperature cycle of each reaction stabilization cycle is the first stage of the manganese salt oxidation reaction: If the negative control intensity of each reaction temperature cycle is greater than a preset first threshold, the value obtained by subtracting the preset temperature from the first temperature value is used as the reaction temperature preset value of the reactor in the next reaction stabilization cycle; If the negative control intensity of each reaction temperature cycle is less than a preset second threshold, the value obtained by adding the preset temperature to the first temperature value is used as the reaction temperature preset value of the reactor in the next reaction stabilization cycle; If the negative control intensity of each reaction temperature cycle is between a first threshold value and a second threshold value, the first temperature value is used as a preset reaction temperature value of the reactor in the next reaction stabilization cycle; wherein the first threshold value is greater than the second threshold value; When the next reaction temperature period of each reaction stabilization period is the second stage of the manganese salt oxidation reaction, a fixed reaction temperature preset value is adopted.

10. The process for producing a manganese manganese oxide material for a battery according to claim 1, wherein: The dehydration, filtration and washing are repeated no less than 3 times.

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