A rapid analysis and detection method for high-concentration components in a preparation solution of a positive electrode material precursor

Abstract

The application discloses a kind of fast analysis detection methods of high-concentration component in cathode material precursor preparation stock solution, comprising the following steps: (1): from the solution sample in the reaction kettle for cathode material precursor preparation;(2): the solution sample is dehydrated and dried, and powder sample is obtained;(3): the powder sample is pressed into solid sample block;(4): the element species and proportion in the solid sample block are determined, that is, the element species and proportion in cathode material precursor preparation stock solution are obtained.The solution sample is converted into solid sample, and solid-phase method analysis is used instead of ICP / chemical titration method, which avoids the disadvantages of long detection time, low detection accuracy, error amplification and high labor consumption caused by frequent dilution of solution sample, and has the advantages of short time consumption, low labor cost and high accuracy.

Description

Technical Field

[0001] This invention belongs to the field of battery materials, and particularly relates to a detection method for the preparation of cathode material precursors. Background Technology

[0002] The composition of ternary precursors is crucial to the morphology, particle size, and electrochemical performance of ternary battery materials, while the concentration of components in the ternary precursor solution determines the elemental composition of the precursor. Currently, typical ternary precursor compositions include NCM523 and NCM811. During production, the molar ratio of Ni, Co, and Mn in the solution must be strictly controlled at 5:2:3 or 8:1:1 to prepare a ternary precursor that meets the requirements. To obtain high-quality, high-performance ternary battery materials, the composition of the ternary precursor preparation solution must be precisely controlled from the source. Therefore, a rapid and accurate analytical method is needed for the ternary precursor preparation process to meet the requirements for real-time online detection of components in high-concentration solutions.

[0003] The metal ion concentration in the ternary precursor stock solution can be as high as 0.5-2.0 mol / L. Existing methods for detecting the concentration of components in the solution include inductively coupled plasma atomic emission spectrometry (ICP) and chemical titration. When these methods are applied to the detection of high-concentration solutions, the solution usually needs to be diluted more than 1000 times. The solution dilution process amplifies the analytical detection error, affects the accuracy of the analysis, and makes it difficult to obtain a solution with a precise ratio of Ni, Co, and Mn. This leads to deviations in the component content of the ternary precursor, ultimately affecting the performance of the ternary material.

[0004] Furthermore, existing methods for analyzing the concentration of ternary precursor solutions all involve manual sampling, sample preparation, and analysis, resulting in high labor costs. The accuracy of the analytical results is significantly affected by the operator's skill level, making it difficult to standardize the production process. Offline analysis is also time-consuming; in actual production, after preparing the ternary precursor solution, it takes approximately 3 hours to obtain the solution composition.

[0005] Therefore, there is an urgent need to develop a technology for rapid and accurate analysis and detection of high-concentration solution components in the production process of ternary precursors. Summary of the Invention

[0006] The technical problem to be solved by this invention is to overcome the shortcomings and defects mentioned in the background art above, and to provide a rapid analytical detection method for high-concentration components in the raw solution for preparing cathode material precursors, which has advantages such as short time consumption, low labor cost, high accuracy, and high degree of automation. To solve the above technical problem, the technical solution proposed by this invention is as follows:

[0007] A rapid analytical detection method for high-concentration components in the raw solution for preparing cathode material precursors includes the following steps:

[0008] (1) Obtain a solution sample from the reactor used for the preparation of cathode material precursors;

[0009] (2) The solution sample is dehydrated and dried to obtain a powder sample;

[0010] (3) The powder sample is pressed into a solid sample block;

[0011] (4) Determine the types and ratios of elements in the solid sample block to obtain the types and ratios of elements in the original solution for preparing the cathode material precursor.

[0012] In the aforementioned rapid analytical detection method, preferably, the solution sample dehydration and drying process employs a solution atomization method. The rapid dehydration and drying method is a solution atomization method, and the drying equipment is computer-programmed and controlled, automatically starting the drying step when the previous sampling operation is completed. The solution sample dehydration and drying method used in this invention has advantages such as high efficiency, controllable particle size of the finished product, and good sample uniformity, which is beneficial to improving the accuracy of subsequent analytical detection.

[0013] In the aforementioned rapid analytical detection methods, preferably, when drying solution samples using the solution nebulization method, an inert gas is used as the carrier gas, the nebulization temperature is controlled at 450-650℃, the nebulized solution flow rate is 30-60 ml / min, and the nebulized carrier gas pressure is 0.05-0.2 MPa; the inert gas is nitrogen or argon. The process parameters of the solution nebulization method have a significant impact on the subsequent analytical results. In this invention, the preferred atomization temperature is 450-650℃. Lower atomization temperatures result in lower powder generation rates, require larger solution volumes, and increase detection time. However, higher atomization temperatures cause sulfates in the sample to decompose into oxides at high temperatures, leading to poor compressibility and difficulty in activating the metal oxide powders, which is detrimental to subsequent detection. Preferably, the atomization solution flow rate is 30-60 ml / min and the atomization carrier gas pressure is 0.05-0.2 MPa. The flow rate and carrier gas pressure determine the particle generation efficiency and particle size. Higher flow rates or lower carrier gas pressures result in difficulty in breaking up the solution, larger atomized droplet sizes, lower powder production efficiency, and larger solid powder particle size. Lower flow rates or higher carrier gas pressures result in smaller atomized particles with larger specific surface areas and faster heat conduction, which can lead to sulfate overheating and decomposition, hindering subsequent detection. Comprehensive and coordinated control of these parameters allows for the production of powder samples that meet the requirements, improving the accuracy of subsequent detection.

[0014] In the aforementioned rapid analytical detection method, preferably, the moisture content of the powder sample is controlled to be <5%, and the particle size is 0.5-3 μm. When the moisture content of the powder sample is low, the molding effect during powder compression is poor, making it difficult to compress into a solid with a certain strength. Furthermore, further reducing the moisture content means increasing the atomization temperature, which may lead to the thermal decomposition of sulfates. Conversely, when the sample moisture content is high, it significantly interferes with the LIBS signal, reducing detection accuracy and sensitivity. When the particle size of the powder sample is large, it results in uneven sample composition. The LIBS laser can only act on the surface of one particle at a time, leading to large fluctuations in the analytical detection results. In addition, the surface smoothness of large particle samples is not as good as that of small particle samples during powder compression. Gaps and unevenness on the sample surface will cause diffuse reflection of light, ultimately affecting the accuracy of LIBS analysis. This invention, by controlling an appropriate particle size, can accelerate the laser ablation rate, speed up heat transfer, generate more plasma, and ultimately increase the spectral intensity, which helps to increase analytical detection accuracy and lower the detection limit.

[0015] In the aforementioned rapid analysis and detection method, preferably, sampling is taken from 1 / 3 to 1 / 2 of the height of the reaction vessel, controlling the volume of the solution sample to 50-200 ml, and obtaining 5-15 g of powder sample after drying. During sampling, a computer-controlled peristaltic pump is used to achieve automatic sampling of a preset fixed volume. Shallow insertion of the sampling tube easily leads to a sample concentration lower than the true value, while deep insertion easily leads to a sample concentration higher than the average value. Controlling the sampling tube to 1 / 3 to 1 / 2 of the height of the reaction vessel is better. The concentration of metal particles in the typical cathode material precursor preparation solution is approximately 1 mol / L, i.e., approximately 150 g of sulfate per liter of solution. When the volume of the obtained solution sample is small, the subsequent dried powder mass is insufficient for compression; when the sample volume is large, too much powder sample is produced, increasing the pressure on subsequent automated cleaning. When the powder sample is small, it is difficult to form a powder tablet sample with sufficient structural strength; when the sample powder is large, it means that the volume of the taken solution sample is large, increasing atomization time and pressure, which is detrimental to improving detection efficiency.

[0016] In the aforementioned rapid analytical detection method, preferably, the metals in the solution sample, powder sample, and solid sample block are all present in the form of metal sulfates. The sulfate solution processed by this invention controls the atomization parameters, and the powder exists in sulfate form, avoiding sulfate decomposition. Sulfates have the advantages of easy sample molding and easy activation; therefore, no additional dopants need to be added during detection, maintaining sample purity.

[0017] In the aforementioned rapid analytical detection method, laser-induced breakdown spectroscopy (LIBS) is preferably used to determine the types and proportions of elements in the solid sample block. LIBS detection of solid sample composition has low sample requirements, short processing time, and high accuracy.

[0018] For the detection of high-concentration components in the precursor preparation solution of cathode materials, this invention uses solution atomization to convert the high-concentration precursor preparation solution into solid powder, which is then analyzed using LIBS. This avoids the problems of long detection time, error accumulation, and decreased detection accuracy caused by frequent dilution of solution samples. It is particularly suitable for the detection of metal content in the synthesis solution of cathode material precursors, including ternary precursors. Furthermore, by controlling the atomization parameters, this invention allows for reasonable control of the generated powder particle size, and the powder remains in the form of sulfate, avoiding sulfate decomposition. Sulfate has the advantages of easy formation and easy activation, so no additional dopants are needed, thus maintaining sample purity.

[0019] The method of this invention can directly use high-concentration solutions as samples for detection. Within the concentration range of 0.1-80%, the detection error is less than 3%, which has a wide range of applications, high detection accuracy, and short detection time (about 20 minutes per sample). It is suitable for rapid detection of high-concentration solutions in large-scale industrial production and experimental processes.

[0020] Compared with the prior art, the advantages of the present invention are as follows:

[0021] 1. The present invention provides a rapid analysis and detection method for high-concentration components in the raw solution for preparing cathode material precursors. This method converts solution samples into solid samples by solution drying and powder preparation, powder tableting, and solid-phase sample detection. The solid-phase method replaces the ICP / chemical titration method, avoiding the disadvantages of frequent solution sample dilution, such as long detection time, low detection accuracy, error amplification, and high manpower consumption. It has the advantages of short time consumption, low labor cost, and high accuracy.

[0022] 2. The rapid analysis and detection method for high-concentration components in the cathode material precursor preparation solution of the present invention enables rapid, accurate and automated detection of the cathode material precursor preparation solution. This method can not only improve the stability of cathode material precursor preparation process, production efficiency and product quality, but also meet the inevitable requirements of intelligent manufacturing and smart industry development. It is of great significance to improving the level of intelligent and automated metallurgy.

[0023] 3. The rapid analysis and detection method for high-concentration components in the precursor preparation solution of the positive electrode material of the present invention has low labor consumption cost and is easy to standardize production. Detailed Implementation

[0024] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below with reference to preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0025] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0026] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0027] Example 1:

[0028] The rapid analysis and detection method for high-concentration components in the ternary precursor preparation solution of this embodiment includes the following steps:

[0029] (1) Obtain a solution sample from the reactor used for the preparation of ternary precursors;

[0030] (2) The solution sample was dehydrated and dried by solution atomization to obtain a powder sample;

[0031] (3) Press the powder sample into a solid sample block;

[0032] (4) The types and ratios of elements in the solid sample block were determined by the LIBS method, thus obtaining the types and ratios of elements in the ternary precursor preparation solution.

[0033] This embodiment provides a rapid analytical detection method for high-concentration components in the ternary precursor preparation solution during a specific production process, including the following steps:

[0034] (1) Turn on the power supply of the electrical control cabinet to supply power and automatically start the analysis and detection program. The high-concentration solution for preparing NCM811 precursor is used as the detection object. The solution in the reactor moves at a constant speed under the action of the stirring paddle. In order to ensure that the sampling is representative, the sampling position is at 1 / 2 of the height of the reactor. Turn on the sampling component (such as a peristaltic pump) to take 100ml of solution from the reactor.

[0035] (2) The solution was dried and powdered by solution atomization. The evaporation temperature was controlled at 500℃, the flow rate of the atomized solution was 50ml / min, and the pressure of the atomized carrier gas was 0.1MPa. 9.47g of NiSO4, CoSO4 and MnSO4 mixture powder was obtained. The powder contained 3.2% water and had an average particle size of 1.5μm.

[0036] (3) Press the powder into a solid sample block.

[0037] (4) Start the detection instrument and use the LIBS detection platform to obtain the component content of Ni 29.43%, Co 3.77% and Mn 3.45%. The molar masses of Ni, Co and Mn are 58.70 g / mol, 58.93 g / mol and 54.94 g / mol, respectively. The molar ratio of Ni:Co:Mn is calculated to be 7.84:1:0.98, and the relative detection error is 2.04%.

[0038] Example 2:

[0039] The rapid analysis and detection method for high-concentration components in the ternary precursor preparation solution of this embodiment includes the following steps:

[0040] (1) Obtain a solution sample from the reactor used for the preparation of ternary precursors;

[0041] (2) The solution sample was dehydrated and dried by solution atomization to obtain a powder sample;

[0042] (3) Press the powder sample into a solid sample block;

[0043] (4) The types and ratios of elements in the solid sample block were determined by the LIBS method, thus obtaining the types and ratios of elements in the ternary precursor preparation solution.

[0044] This embodiment provides a rapid analytical detection method for high-concentration components in the ternary precursor preparation solution during a specific production process, including the following steps:

[0045] (1) Turn on the power supply of the electrical control cabinet to supply power and automatically start the analysis and detection program. The high-concentration solution for preparing NCM811 precursor is used as the detection object. The solution in the reactor moves at a constant speed under the action of the stirring paddle. In order to ensure that the sampling is representative, the sampling position is at 1 / 2 of the height of the reactor. Turn on the sampling component (such as a peristaltic pump) to take 100ml of solution from the reactor.

[0046] (2) The solution was dried and powdered by solution atomization. The evaporation temperature was controlled at 450℃, the flow rate of the atomized solution was 60ml / min, and the pressure of the atomized carrier gas was 0.05MPa. 7.5g of NiSO4, CoSO4 and MnSO4 mixture powder was obtained. The powder contained 4.7% water and had an average particle size of 3μm.

[0047] (3) Press the powder into a solid sample block.

[0048] (4) Start the detection instrument and use the LIBS detection platform to obtain the component content of Ni 28.27%, Co 3.65% and Mn 3.39%. The molar masses of Ni, Co and Mn are 58.70 g / mol, 58.93 g / mol and 54.94 g / mol, respectively. The molar ratio of Ni:Co:Mn is calculated to be 7.77:1:1, and the relative error of detection is 2.80%.

[0049] Example 3:

[0050] The rapid analysis and detection method for high-concentration components in the ternary precursor preparation solution of this embodiment includes the following steps:

[0051] (1) Obtain a solution sample from the reactor used for the preparation of ternary precursors;

[0052] (2) The solution sample was dehydrated and dried by solution atomization to obtain a powder sample;

[0053] (3) Press the powder sample into a solid sample block;

[0054] (4) The types and ratios of elements in the solid sample block were determined by the LIBS method, thus obtaining the types and ratios of elements in the ternary precursor preparation solution.

[0055] This embodiment provides a rapid analytical detection method for high-concentration components in the ternary precursor preparation solution during a specific production process, including the following steps:

[0056] (1) Turn on the power supply of the electrical control cabinet to supply power and automatically start the analysis and detection program. The high-concentration solution for preparing NCM811 precursor is used as the detection object. The solution in the reactor moves at a constant speed under the action of the stirring paddle. In order to ensure that the sampling is representative, the sampling position is at 1 / 2 of the height of the reactor. Turn on the sampling component (such as a peristaltic pump) to take 100ml of solution from the reactor.

[0057] (2) The solution was dried and powdered by solution atomization. The evaporation temperature was controlled at 650℃, the flow rate of the atomizing solution was 30ml / min, and the pressure of the atomizing carrier gas was 0.2MPa. 8.91g of NiSO4, CoSO4 and MnSO4 mixture powder was obtained. The powder contained 2.4% water and had an average particle size of 0.5μm.

[0058] (3) Press the powder into a solid sample block.

[0059] (4) Start the detection instrument and use the LIBS detection platform to obtain the component content of Ni 29.23%, Co 3.61% and Mn 3.37%. The molar masses of Ni, Co and Mn are 58.70 g / mol, 58.93 g / mol and 54.94 g / mol, respectively. The molar ratio of Ni:Co:Mn is calculated to be 8.13:1:1, and the relative error of detection is 1.61%.

[0060] Comparative Example 1:

[0061] The rapid analytical detection method for high-concentration components in the ternary precursor preparation solution of this comparative example includes the following steps:

[0062] (1) Obtain a solution sample from the reactor used for the preparation of ternary precursors;

[0063] (2) The solution sample was dehydrated and dried by solution atomization to obtain a powder sample;

[0064] (3) Press the powder sample into a solid sample block;

[0065] (4) The types and ratios of elements in the solid sample block were determined by the LIBS method, thus obtaining the types and ratios of elements in the ternary precursor preparation solution.

[0066] This comparative example provides a rapid analytical detection method for high-concentration components in the ternary precursor preparation solution during a specific production process, including the following steps:

[0067] (1) Turn on the power supply of the electrical control cabinet to supply power and automatically start the analysis and detection program. The high-concentration solution for preparing NCM811 precursor is used as the detection object. The solution in the reactor moves at a constant speed under the action of the stirring paddle. In order to ensure that the sampling is representative, the sampling position is at 1 / 2 of the height of the reactor. Turn on the sampling component (such as a peristaltic pump) to take 100ml of solution from the reactor.

[0068] (2) The solution was dried and powdered by solution atomization. The evaporation temperature was controlled at 400℃, the flow rate of the atomizing solution was 50ml / min, and the pressure of the atomizing carrier gas was 0.2MPa. 6.65g of NiSO4, CoSO4 and MnSO4 mixture powder was obtained. The powder contained 8.43% water and had an average particle size of 4.22μm.

[0069] (3) Press the powder into a solid sample block.

[0070] (4) Start the detection instrument. Using the LIBS detection platform, start the detection instrument and obtain the component content as Ni 28.69%, Co 3.81%, and Mn 3.73%. The molar masses of Ni, Co, and Mn are 58.70 g / mol, 58.93 g / mol, and 54.94 g / mol, respectively. The molar ratio of Ni:Co:Mn is calculated to be 7.51:1:1.05, and the relative detection error is 5.50%.

[0071] Comparative Example 2:

[0072] The rapid analytical detection method for high-concentration components in the ternary precursor preparation solution of this comparative example includes the following steps:

[0073] (1) Obtain a solution sample from the reactor used for the preparation of ternary precursors;

[0074] (2) The solution sample was dehydrated and dried by atmospheric pressure drying to obtain a powder sample;

[0075] (3) Press the powder sample into a solid sample block;

[0076] (4) The types and ratios of elements in the solid sample block were determined by the LIBS method, thus obtaining the types and ratios of elements in the ternary precursor preparation solution.

[0077] This comparative example provides a rapid analytical detection method for high-concentration components in the ternary precursor preparation solution during a specific production process, including the following steps:

[0078] (1) Turn on the power supply of the electrical control cabinet to supply power and automatically start the analysis and detection program. The high-concentration solution for preparing NCM811 precursor is used as the detection object. The solution in the reactor moves at a constant speed under the action of the stirring paddle. In order to ensure that the sampling is representative, the sampling position is at 1 / 2 of the height of the reactor. Turn on the sampling component (such as a peristaltic pump) to take 100ml of solution from the reactor.

[0079] (2) Place the stainless steel container containing the solution in an oven, set the drying temperature to 200℃, and dry for 2 hours under normal pressure to obtain 10.87g of NiSO4, CoSO4 and MnSO4 mixture powder with a water content of 1.35% and an average particle size of 8.62μm.

[0080] (3) Press the powder into a solid sample block.

[0081] (4) Start the detection instrument and use the LIBS detection platform to obtain the component content of Ni 31.13%, Co 3.61%, and Mn 3.22%. The molar masses of Ni, Co, and Mn are 58.70 g / mol, 58.93 g / mol, and 54.94 g / mol, respectively. The molar ratio of Ni:Co:Mn is calculated to be 8.66:1:0.96, and the relative detection error is 8.21%.

Claims

1. A rapid analytical method for detecting high-concentration components in the raw solution for preparing cathode material precursors, characterized in that, Includes the following steps: (1) Obtain a solution sample from the reactor used for the preparation of cathode material precursors; (2) Dehydrate and dry the solution sample to obtain a powder sample; (3) Press the powder sample into a solid sample block; (4) Determine the types and proportions of elements in the solid sample block to obtain the types and proportions of elements in the original solution for preparing the cathode material precursor; The solution sample was dehydrated and dried using a solution atomization method. When drying solution samples using the solution atomization method, an inert gas is used as the carrier gas, the atomization temperature is controlled at 450-650℃, the atomization solution flow rate is 30-60 ml / min, and the atomization carrier gas pressure is 0.05-0.2 MPa; the inert gas is nitrogen or argon. The metals in the solution samples, powder samples, and solid sample blocks all exist in the form of metal sulfates. The LIBS method was used to determine the types and proportions of elements in the solid sample block. The moisture content of the powder sample should be controlled to be <5%, and the particle size should be 0.5-3μm.

2. The rapid analysis and detection method according to claim 1, characterized in that, Samples are taken from 1 / 3 to 1 / 2 of the height of the reaction vessel, and the volume of the solution sample is controlled at 50-200 ml. After drying, 5-15 g of powder sample is obtained.