Method for testing positive electrode manganese dissolution of a battery

Abstract

This invention provides a method for testing the leaching of manganese from the positive electrode of a battery. The method includes the following steps: taking a positive electrode sheet that has been cycled a specified number of times as a test sample and taking an uncycled positive electrode sheet as a control sample; sintering the test sample and the control sample respectively; subjecting the sintered test sample and the control sample to acid dissolution treatment to obtain a test solution and a control solution respectively; and analyzing the test solution and the control solution respectively to determine the content of Mn element, and then calculating the leaching rate of Mn element in the test sample. The method for testing the leaching of manganese from the positive electrode of a battery provided by this invention effectively solves the problems of organic matter interfering with acid leaching efficiency and affecting the stability of the detection matrix in traditional methods, avoids test deviations and equipment damage caused by solid carbon particles, and improves the accuracy of test results.

Description

Technical Field

[0001] This invention relates to the field of battery testing technology, and in particular to a test method for manganese leaching from the positive electrode of a battery. Background Technology

[0002] During battery cycling, manganese in the cathode material dissolves into the electrolyte. The dissolution of manganese ions not only alters the cathode material structure and disrupts the SEI composition, but also migrates and deposits on the anode, affecting lithium-ion insertion / extraction and thus shortening battery cycle life. Therefore, manganese dissolution testing is one way to evaluate battery performance.

[0003] Traditional manganese leaching tests typically involve acid leaching of the solution followed by ICP-OES (Inductively Coupled Plasma Optical Emission Spectrometry), ICP-MS (Inductively Coupled Plasma Mass Spectrometry), or atomic absorption spectrometry. However, these methods have significant drawbacks. Residual binders (such as PVDF), conductive agents, electrolytes, and organic solvents on the electrode sheets can affect acid leaching efficiency, cause incomplete digestion, and easily lead to foaming and splashing. Furthermore, organic groups can interfere with the matrix, reducing the stability and accuracy of ICP measurements. Incomplete pretreatment to remove or oxidize organic matter can result in overestimation or underestimation of manganese levels and poor repeatability. Moreover, incompletely digested solid carbon particles can simultaneously cause deviations in test accuracy and damage to the equipment. Summary of the Invention

[0004] Therefore, it is necessary to provide a test method for manganese leaching from the positive electrode of a battery. The positive electrode sheet is sintered and then acid-dissolved. The content of Mn element in the solution is measured by test analysis. By setting an uncirculated positive electrode sheet as a control sample, the dissolution rate of Mn element is calculated. This solves the problem of organic matter interfering with acid leaching efficiency and affecting the stability of the detection matrix in traditional methods, thereby improving the accuracy of test results.

[0005] This invention provides a test method for manganese leaching from the positive electrode of a battery, comprising the following steps:

[0006] Take the positive electrode that has been circulated a specified number of times as the test sample, and take the positive electrode that has not been circulated as the control sample;

[0007] The test sample and the control sample were sintered respectively.

[0008] The test sample and the control sample that have undergone the sintering treatment are respectively subjected to acid dissolution treatment to obtain test solution and control solution;

[0009] The test solution and the control solution were tested and analyzed separately to determine the content of Mn element, and then the dissolution rate of Mn element in the test sample was calculated.

[0010] In some embodiments, the sintering process is carried out at a temperature of 300°C to 500°C for a duration of 4 to 6 hours.

[0011] In some embodiments, the acid dissolution treatment uses a solution including sulfuric acid, hydrochloric acid, or nitric acid.

[0012] In some embodiments, the acid dissolution treatment is performed at a temperature of 75°C to 85°C.

[0013] In some embodiments, the method for testing manganese leaching from the battery cathode prior to the sintering process further includes the following steps:

[0014] The test sample and the control sample were rinsed and dried using a solvent, respectively.

[0015] In some embodiments, the rinsing process includes rinsing with anhydrous dimethyl carbonate followed by rinsing with anhydrous ethanol.

[0016] In some embodiments, the test analysis is performed using ICP-OES (Inductively Coupled Plasma Emission Spectroscopy).

[0017] In some embodiments, the test analysis yields the concentration of Mn in the control solution and the test solution;

[0018] The dissolution rate of Mn element in the test sample is calculated using equation (1):

[0019] Equation (1)

[0020] In equation (1), j is the dissolution rate of Mn element in the test sample, C1 is the concentration of Mn element in the control sample, and C2 is the concentration of Mn element in the test sample.

[0021] In some embodiments, the cathode material in the test sample and the control sample is at least one of LMFP, LMO, and NCM.

[0022] In some embodiments, when the cathode material is LMFP, the acid dissolution treatment is performed at a temperature of 80°C to 85°C for 4 to 5 hours; when the cathode material is LMO or NCM, the acid dissolution treatment is performed at a temperature of 75°C to 80°C for 3 to 3.5 hours.

[0023] Compared with traditional technologies, the present invention has the following advantages:

[0024] The present invention provides a method for testing manganese leaching from battery cathodes. This method involves sintering the cathode sheet to remove organic binders (such as PVDF) and conductive agents (such as carbon black) from the sample, resulting in a loosely structured sintered product that is readily acid-soluble. The product is then subjected to acid dissolution treatment to form a solution for testing. Finally, the content of Mn in the solution is measured through testing and analysis. By using a non-circulated cathode sheet as a control sample, the Mn leaching rate can be calculated. This method effectively solves the problems of organic matter interfering with acid leaching efficiency and affecting the stability of the detection matrix in traditional methods, avoids test deviations and equipment damage caused by solid carbon particles, and improves the accuracy of test results. Attached Figure Description

[0025] Figure 1 This is a schematic flowchart of a test method for manganese leaching from the positive electrode of a battery, according to one embodiment. Detailed Implementation

[0026] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein; these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0027] It should be noted that when an element is referred to as being "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0028] In the description of this invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number or order of the indicated technical features.

[0029] Unless otherwise defined, 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 invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0030] Unless otherwise specified, all steps of this invention may be performed sequentially or randomly. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the method may also include step (c), indicating that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0031] like Figure 1 As shown, a method for testing manganese leaching from the positive electrode of a battery according to an embodiment of the present invention includes the following steps:

[0032] Step S1: Take a positive electrode that has been circulated a specified number of times as a test sample, and take a positive electrode that has not been circulated as a control sample.

[0033] Step S2: Sinter the test sample and the control sample respectively.

[0034] Step S3: The sintered test sample and control sample are subjected to acid dissolution treatment to obtain test solution and control solution, respectively.

[0035] Step S4: The test solution and the control solution are tested and analyzed respectively to determine the content of Mn element, and then the dissolution rate of Mn element in the test sample is calculated.

[0036] The aforementioned method for testing manganese leaching from the battery cathode involves sintering the cathode sheet to remove organic binders (such as PVDF) and conductive agents (such as carbon black) from the sample, resulting in a loosely structured sintered product that is readily acid-soluble. This is followed by acid dissolution to form a solution for testing. Finally, the Mn content in the solution is measured through analysis, and the Mn leaching rate can be calculated by using a non-circulated cathode sheet as a control. This method effectively solves the problems of organic matter interfering with acid leaching efficiency and affecting the stability of the detection matrix in traditional methods, avoids test deviations and equipment damage caused by solid carbon particles, and improves the accuracy of test results.

[0037] In step S1, the test sample and the control sample have the same positive electrode material and the same content, the difference being whether they have undergone battery charge-discharge cycles. It can be understood that the difference between the mass of Mn element in the test sample and the mass of Mn element in the control sample is the mass of manganese dissolved from the positive electrode after a specified number of cycles.

[0038] Optionally, the cathode material in the test and control samples can be, for example, but not limited to, lithium manganese iron phosphate (LiMn). x Fe 1-xExamples of suitable cathode materials include lithium nickel cobalt manganese oxide (LiMn2O4, LMO) and lithium phosphite (LMFP), which are rich in manganese.

[0039] Test and control samples should be free from external contamination and have smooth surfaces. Any non-electrode materials or impurities adhering to the electrode sheets must be properly cleaned.

[0040] In some of these examples, the test method for manganese leaching from the battery cathode prior to the sintering process (step S2) also includes the following steps:

[0041] The test samples and control samples were rinsed and dried using solvents.

[0042] In the example above, rinsing removes organic matter, such as electrolyte and organic binders (e.g., PVDF), from the positive electrode. This reduces the influence of non-positive electrode materials and improves the accuracy of the test.

[0043] In some examples, the rinsing process includes rinsing with anhydrous dimethyl carbonate (DMC) three to four times, for example, but not limited to, rinsing with anhydrous ethanol two to three times, for example, but not limited to, rinsing with anhydrous ethanol. Finally, the positive electrode is dried to remove residual DMC and ethanol from the surface.

[0044] In step S2, the organic binder (such as PVDF) and conductive agent (such as carbon black) in the sample are completely removed by sintering, resulting in a sintered product with a loose structure that is easy to dissolve in acid.

[0045] In some examples, the sintering temperature in step S2 is 300℃~500℃. Further, in some examples, the sintering temperature is 350℃~450℃. In some specific examples, the sintering temperature is, for example, 300℃, 310℃, 320℃, 330℃, 340℃, 350℃, 360℃, 370℃, 380℃, 390℃, 400℃, 410℃, 420℃, 430℃, 440℃, 450℃, 460℃, 470℃, 480℃, 490℃, 500℃, etc., or a range between any two of the above values.

[0046] In some examples, the sintering time in step S2 is 4h to 6h. Further, in some examples, the sintering time is 4.5h to 5.5h. In some specific examples, the sintering time is, for example, 4h, 4.1h, 4.2h, 4.3h, 4.4h, 4.5h, 4.6h, 4.7h, 4.8h, 4.9h, 5h, 5.1h, 5.2h, 5.3h, 5.4h, 5.5h, 5.6h, 5.7h, 5.8h, 5.9h, or 6h.

[0047] In some of these examples, in step S3, the acid solution used for the acid dissolution treatment is sulfuric acid (H2SO4), hydrochloric acid (HCl), or nitric acid (HNO3).

[0048] In some examples, the acid dissolution treatment temperature in step S3 is 75℃~85℃. In some specific examples, the acid dissolution treatment temperature is, for example, 75℃, 75.5℃, 76℃, 76.5℃, 77℃, 77.5℃, 78℃, 78.5℃, 79℃, 79.5℃, 80℃, 80.5℃, 81℃, 81.5℃, 82℃, 82.5℃, 83℃, 83.5℃, 84℃, 84.5℃, 85℃, etc., or a range between any two of the above values.

[0049] In some examples, the acid dissolution treatment time in step S3 is 3h to 5h. In some specific examples, the sintering treatment time is, for example, 3h, 3.1h, 3.2h, 3.3h, 3.4h, 3.5h, 3.6h, 3.7h, 3.8h, 3.9h, 4h, 4.1h, 4.2h, 4.3h, 4.4h, 4.5h, 4.6h, 4.7h, 4.8h, 4.9h, 5h, etc.

[0050] In step S3, for LMFP samples, it is preferred to dissolve them by heating at 80°C to 85°C for 4 to 5 hours. For LMO and NCM samples, it is preferred to dissolve them by heating at 75°C to 80°C for 3 to 3.5 hours.

[0051] In some of these examples, the acid dissolution process in step S3 includes the following steps:

[0052] Take 0.1g of the sintered product and place it in a container (such as a PTFE beaker or conical flask). Add 5mL of concentrated nitric acid and 1mL of hydrogen peroxide, and let it stand at room temperature for 5 minutes to pre-dissolve, ensuring the sample is in full contact with the acid solution. Then place the container on a heating plate and control the solution to a gentle boiling state. Adjust the acid dissolution temperature and time according to the type of cathode material: Lithium manganese iron phosphate (LMFP) samples are heated to 80~85℃ for 4~5h, and lithium manganese oxide (LMO) and manganese-rich ternary cathode material lithium nickel cobalt manganese oxide (NCM) samples are heated to 75~80℃ for 3~3.5h, until the solution is light pink or colorless and transparent, indicating that Fe and Mn have completely dissolved. During the acid dissolution process, if the acid solution volume decreases by more than 2mL, add 2mL of concentrated nitric acid. If slight turbidity occurs, add 0.5mL of concentrated nitric acid and continue heating until the solution is transparent.

[0053] In some of these examples, in step S4, the test analysis uses a measurement method to measure the concentration of Mn in the test solution and the control solution, respectively.

[0054] In some of these examples, the determination method was ICP-OES (inductively coupled plasma optical emission spectrometry) to measure the concentration of Mn in the solution.

[0055] It can be understood that the difference between the concentration of Mn in the control sample and the concentration of Mn in the test sample is the concentration of manganese dissolved from the positive electrode after a specified number of cycles. Further, the dissolution rate of Mn in the test sample is calculated using equation (1):

[0056] Equation (1)

[0057] In formula (1), j is the dissolution rate of Mn element in the test sample, C1 is the concentration of Mn element in the control sample in mg / L, and C2 is the concentration of Mn element in the test sample in mg / L.

[0058] The aforementioned method for testing manganese leaching from the positive electrode of a battery involves sintering the positive electrode sheet to remove organic binders (such as PVDF) and conductive agents (such as carbon black) from the sample, resulting in a loosely structured sintered product that is readily acid-soluble. This is followed by acid dissolution treatment to form a solution for testing. Analysis of the solution reveals the Mn content. This method effectively solves the problems of organic matter interfering with acid leaching efficiency and affecting the stability of the detection matrix in traditional methods, avoids test deviations and equipment damage caused by solid carbon particles, and improves the accuracy of test results.

[0059] The following specific embodiments further illustrate the present invention. These specific embodiments are provided to better understand the present invention, but are not intended to limit the scope of the invention and do not constitute a limitation on its content or protection.

[0060] Example 1

[0061] This embodiment provides a test method for manganese leaching from the positive electrode of a battery, including the following steps:

[0062] Step 1, Sample Preparation. Select a positive electrode sheet from a battery that has undergone a certain number of cycles as the test sample, and take an uncycled positive electrode sheet as the control sample. The positive electrode material is LMFP. Ensure that it is free from external contamination and that the surface of the positive electrode sheet is flat. If any non-electrode materials or impurities adhere to the positive electrode sheet, it needs to be cleaned appropriately.

[0063] Step 2, electrode rinsing. Soak and rinse the positive electrode material on the test sample and control sample three times with anhydrous dimethyl carbonate, then rinse the positive electrode material twice with anhydrous ethanol. Finally, dry the test sample and control sample to remove residual dimethyl carbonate and ethanol from the surface.

[0064] Step 3, high-temperature sintering. The test sample and control sample are placed in a high-temperature furnace for sintering. The sintering temperature is 500℃ and the treatment time is 3 hours to remove any residual organic matter and carbon materials that may be present on the sample surface.

[0065] Step 4, Acid Dissolution Treatment. Place 0.1g of the sintered product in a polytetrafluoroethylene (PTFE) beaker, add 5mL of concentrated nitric acid and 1mL of hydrogen peroxide, and allow to stand at room temperature for 5 minutes to pre-dissolve, ensuring sufficient contact between the sample and the acid solution. Then place the beaker on a heating plate, adjusting the temperature and time according to the material type, stirring continuously with the beaker open (or stirring once every 20 minutes), controlling the solution to a gentle boiling state (avoiding vigorous boiling that could lead to significant acid evaporation). Heat the sample at 85℃ for 4 hours until the solution is light pink or colorless and transparent, indicating that elemental dissolution is complete. If the acid volume decreases by more than 2mL during dissolution, add 2mL of nitric acid; if slight turbidity occurs during dissolution, add 0.5mL of concentrated nitric acid and continue heating for 30 minutes until the solution is clear.

[0066] Step 5, Testing and Analysis. The dissolved solution contains Fe, Mn, and Al elements. The concentration of Mn in the solution was determined by ICP-OES.

[0067] Step 6, Calculation and Analysis. Based on the Mn element concentration before and after the cycle obtained from ICP-OES testing, since the dilution factor is the same, the Mn dissolution ratio can be calculated using the concentration ratio.

[0068] It can be understood that the difference between the concentration of Mn in the control sample and the concentration of Mn in the test sample is the concentration of manganese dissolved from the positive electrode after a specified number of cycles. Furthermore, the dissolution rate of Mn is calculated using equation (1):

[0069] Equation (1)

[0070] In formula (1), j is the dissolution rate of Mn element in the test sample, C1 is the concentration of Mn element in the control sample in mg / L, and C2 is the concentration of Mn element in the test sample in mg / L.

[0071] Example 2

[0072] This embodiment provides a test method for manganese leaching from the positive electrode of a battery, including the following steps:

[0073] Step 1, Sample Preparation. Select a positive electrode sheet from a battery that has undergone a certain number of cycles as the test sample, and take an uncycled positive electrode sheet as the control sample. The positive electrode material is LMFP. Ensure that it is free from external contamination and that the surface of the positive electrode sheet is flat. If any non-electrode materials or impurities adhere to the positive electrode sheet, it needs to be cleaned appropriately.

[0074] Step 2, electrode rinsing. Soak and rinse the positive electrode material on the test sample and control sample 4 times with anhydrous dimethyl carbonate, then rinse the positive electrode material 3 times with anhydrous ethanol. Finally, dry the test sample and control sample to remove residual dimethyl carbonate and ethanol from the surface.

[0075] Step 3, high-temperature sintering. The test sample and control sample are placed in a high-temperature furnace for sintering. The sintering temperature is 400℃ and the treatment time is 5 hours to remove any residual organic matter and carbon materials that may be present on the sample surface.

[0076] Step 4, Acid Dissolution Treatment. Place 0.1g of the sintered product in a polytetrafluoroethylene (PTFE) beaker, add 5mL of concentrated hydrochloric acid and 1mL of hydrogen peroxide, and allow to stand at room temperature for 5 minutes to pre-dissolve, ensuring sufficient contact between the sample and the acid solution. Then place the beaker on a heating plate, adjusting the temperature and time according to the material type, and stir continuously with the beaker open (or stir every 20 minutes), controlling the solution to a gentle boiling state (avoiding vigorous boiling that could lead to significant acid evaporation). Heat the sample at 80℃ for 5 hours until the solution is light pink or colorless and transparent, indicating that elemental dissolution is complete. If the acid volume decreases by more than 2mL during dissolution, add 2mL of nitric acid; if slight turbidity occurs during dissolution, add 0.5mL of concentrated nitric acid and continue heating for 30 minutes until the solution becomes clear.

[0077] Step 5, Testing and Analysis. The dissolved solution contains Fe, Mn, and Al elements. The concentration of Mn in the solution was determined by ICP-OES.

[0078] Step 6, Calculation and Analysis. Based on the Mn element concentration before and after the cycle obtained from ICP-OES testing, since the dilution factor is the same, the Mn dissolution ratio can be calculated using the concentration ratio.

[0079] It can be understood that the difference between the concentration of Mn in the control sample and the concentration of Mn in the test sample is the concentration of manganese dissolved from the positive electrode after a specified number of cycles. Furthermore, the dissolution rate of Mn is calculated using equation (1):

[0080] Equation (1)

[0081] In formula (1), j is the dissolution rate of Mn element in the test sample, C1 is the concentration of Mn element in the control sample in mg / L, and C2 is the concentration of Mn element in the test sample in mg / L.

[0082] Example 3

[0083] This embodiment provides a test method for manganese leaching from the positive electrode of a battery, including the following steps:

[0084] Step 1, Sample Preparation. Select a positive electrode sheet from a battery that has undergone a certain number of cycles as the test sample, and take an uncycled positive electrode sheet as the control sample. The positive electrode material is LMO. Ensure that it is free from external contamination and that the surface of the positive electrode sheet is flat. If any non-electrode materials or impurities adhere to the positive electrode sheet, it needs to be cleaned appropriately.

[0085] Step 2, electrode rinsing. Soak and rinse the positive electrode material on the test sample and control sample three times with anhydrous dimethyl carbonate, then rinse the positive electrode material twice with anhydrous ethanol. Finally, dry the test sample and control sample to remove residual dimethyl carbonate and ethanol from the surface.

[0086] Step 3, high-temperature sintering. The test sample and control sample are placed in a high-temperature furnace for sintering. The sintering temperature is 400℃ and the treatment time is 5 hours to remove any residual organic matter and carbon materials that may be present on the sample surface.

[0087] Step 4, Acid Dissolution Treatment. Place 0.1g of the sintered product in a polytetrafluoroethylene (PTFE) beaker, add 5mL of concentrated sulfuric acid and 1mL of hydrogen peroxide, and allow to stand at room temperature for 5 minutes to pre-dissolve, ensuring sufficient contact between the sample and the acid solution. Then place the beaker on a heating plate, adjusting the temperature and time according to the material type, stirring continuously with the beaker open (or stirring once every 20 minutes), controlling the solution to a gentle boiling state (avoiding vigorous boiling that could cause significant acid evaporation). Heat the sintered sample at 80℃ for 3 hours until the solution is light pink or colorless and transparent, indicating that elemental dissolution is complete. If the acid volume decreases by more than 2mL during dissolution, add 2mL of nitric acid; if slight turbidity occurs during dissolution, add 0.5mL of concentrated nitric acid and continue heating for 30 minutes until the solution is clear.

[0088] Step 5, Testing and Analysis. The dissolved solution contains Fe, Mn, and Al elements. The concentration of Mn in the solution was determined by ICP-OES.

[0089] Step 6, Calculation and Analysis. Based on the Mn element concentration before and after the cycle obtained from ICP-OES testing, since the dilution factor is the same, the Mn dissolution ratio can be calculated using the concentration ratio.

[0090] It can be understood that the difference between the concentration of Mn in the control sample and the concentration of Mn in the test sample is the concentration of manganese dissolved from the positive electrode after a specified number of cycles. Furthermore, the dissolution rate of Mn is calculated using equation (1):

[0091] Equation (1)

[0092] In formula (1), j is the dissolution rate of Mn element in the test sample, C1 is the concentration of Mn element in the control sample in mg / L, and C2 is the concentration of Mn element in the test sample in mg / L.

[0093] Example 4

[0094] This embodiment provides a test method for manganese leaching from the positive electrode of a battery, including the following steps:

[0095] Step 1, Sample Preparation. Select a positive electrode sheet from a battery that has undergone a certain number of cycles as the test sample, and take an uncycled positive electrode sheet as the control sample. The positive electrode material is NCM. Ensure that it is free from external contamination and that the surface of the positive electrode sheet is flat. If any non-electrode materials or impurities adhere to the positive electrode sheet, it needs to be cleaned appropriately.

[0096] Step 2, electrode rinsing. Soak and rinse the positive electrode material on the test sample and control sample three times with anhydrous dimethyl carbonate, then rinse the positive electrode material twice with anhydrous ethanol. Finally, dry the test sample and control sample to remove residual dimethyl carbonate and ethanol from the surface.

[0097] Step 3, high-temperature sintering. The test sample and control sample are placed in a high-temperature furnace for sintering. The sintering temperature is 300℃ and the treatment time is 6 hours to remove any residual organic matter and carbon materials that may be present on the sample surface.

[0098] Step 4, Acid Dissolution Treatment. Place 0.1g of the sintered product in a polytetrafluoroethylene (PTFE) beaker, add 5mL of concentrated nitric acid and 1mL of hydrogen peroxide, and allow to stand at room temperature for 5 minutes to pre-dissolve, ensuring sufficient contact between the sample and the acid solution. Then place the beaker on a heating plate, adjusting the temperature and time according to the material type, stirring continuously with the beaker open (or stirring once every 20 minutes), controlling the solution to a gentle boiling state (avoiding vigorous boiling that could lead to significant acid evaporation). Heat the sintered sample at 75℃ for 3.5 hours until the solution is light pink or colorless and transparent, indicating that elemental dissolution is complete. If the acid volume decreases by more than 2mL during dissolution, add 2mL of nitric acid; if slight turbidity occurs during dissolution, add 0.5mL of concentrated nitric acid and continue heating for 30 minutes until the solution is clear.

[0099] Step 5, Testing and Analysis. The dissolved solution contains Fe, Mn, and Al elements. The concentration of Mn in the solution was determined by ICP-OES.

[0100] Step 6, Calculation and Analysis. Based on the Mn element concentration before and after the cycle obtained from ICP-OES testing, since the dilution factor is the same, the Mn dissolution ratio can be calculated using the concentration ratio.

[0101] It can be understood that the difference between the concentration of Mn in the control sample and the concentration of Mn in the test sample is the concentration of manganese dissolved from the positive electrode after a specified number of cycles. Furthermore, the dissolution rate of Mn is calculated using equation (1):

[0102] Equation (1)

[0103] In formula (1), j is the dissolution rate of Mn element in the test sample, C1 is the concentration of Mn element in the control sample in mg / L, and C2 is the concentration of Mn element in the test sample in mg / L.

[0104] Compared with traditional technologies, the test method for manganese leaching from the battery cathode in the above embodiments has the following technical advantages:

[0105] 1. Elimination of interference: Through pretreatment processes such as DMC, anhydrous ethanol rinsing and high-temperature sintering, the electrolyte and PVDF are removed first, and then organic matter such as carbon black is completely oxidized and decomposed into CO2 gas and released. This effectively solves the problem of organic matter interfering with acid leaching efficiency and affecting the stability of the detection matrix in traditional methods, and avoids test deviations and equipment damage caused by solid carbon particles.

[0106] 2. Avoid loss of positive electrode material: Instead of scraping the positive electrode material, the positive electrode sheet is dissolved as a whole. The current collector and the positive electrode material are dissolved together with acid to ensure complete collection of the positive electrode material and improve the accuracy of the test results.

[0107] 3. High testing accuracy and good repeatability: The ICP-OES method is used to determine the manganese content and realize the quantitative calculation of manganese content, which can achieve accurate quantification and significantly improve the accuracy and repeatability of test results.

[0108] 4. Strong process adaptability: For mainstream manganese-containing cathode materials such as LMFP, LMO, and NCM, the temperature and time parameters of acid dissolution treatment have been optimized, which can achieve complete dissolution of metal elements in different materials and is suitable for manganese dissolution testing of various manganese-containing lithium-ion battery cathode materials.

[0109] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0110] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this patent should be determined by the appended claims.

Claims

1. A test method for manganese leaching from a battery cathode, characterized in that, Includes the following steps: Take the positive electrode that has been circulated a specified number of times as the test sample, and take the positive electrode that has not been circulated as the control sample; The test sample and the control sample were sintered respectively. The test sample and the control sample that have undergone the sintering treatment are respectively subjected to acid dissolution treatment to obtain test solution and control solution; The test solution and the control solution were tested and analyzed separately to determine the content of Mn element, and then the dissolution rate of Mn element in the test sample was calculated.

2. The test method for manganese leaching from the positive electrode of a battery as described in claim 1, characterized in that, The sintering process is carried out at a temperature of 300℃ to 500℃ for a duration of 4 to 6 hours.

3. The test method for manganese leaching from the positive electrode of a battery as described in claim 1, characterized in that, The solutions used in the acid dissolution treatment include sulfuric acid, hydrochloric acid, or nitric acid.

4. The test method for manganese leaching from the positive electrode of a battery as described in claim 1, characterized in that, The acid dissolution treatment is performed at a temperature of 75℃~85℃.

5. The test method for manganese leaching from the positive electrode of a battery as described in claim 1, characterized in that, Prior to the sintering process, the test method for manganese leaching from the battery cathode further includes the following steps: The test sample and the control sample were rinsed and dried using a solvent, respectively.

6. The test method for manganese leaching from the positive electrode of a battery as described in claim 5, characterized in that, The rinsing process includes rinsing with anhydrous dimethyl carbonate first, and then rinsing with anhydrous ethanol.

7. The test method for manganese leaching from the positive electrode of a battery as described in claim 1, characterized in that, The test and analysis method is ICP-OES.

8. The test method for manganese leaching from the positive electrode of a battery as described in claim 6, characterized in that, The test analysis yielded the concentration of Mn in the control solution and the test solution; The dissolution rate of Mn element in the test sample is calculated using equation (1): Equation (1) In equation (1), j is the dissolution rate of Mn element in the test sample, C1 is the concentration of Mn element in the control sample, and C2 is the concentration of Mn element in the test sample.

9. The test method for manganese leaching from the positive electrode of a battery as described in any one of claims 1-5 and 7-8, characterized in that, The cathode material in the test sample and the control sample is at least one of LMFP, LMO and NCM.

10. The test method for manganese leaching from the positive electrode of a battery as described in claim 9, characterized in that, When the cathode material is LMFP, the acid dissolution treatment temperature is 80℃~85℃ and the time is 4h~5h; when the cathode material is LMO or NCM, the acid dissolution treatment temperature is 75℃~80℃ and the time is 3h~3.5h.

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