CN116359205A - Method for detecting surface tungsten in ternary cathode material - Google Patents
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- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 title claims abstract description 34
- 229910052721 tungsten Inorganic materials 0.000 title claims abstract description 34
- 239000010937 tungsten Substances 0.000 title claims abstract description 34
- 238000000034 method Methods 0.000 title claims abstract description 33
- 239000010406 cathode material Substances 0.000 title claims description 15
- 239000000523 sample Substances 0.000 claims abstract description 39
- 239000012086 standard solution Substances 0.000 claims abstract description 25
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical class [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 claims abstract description 23
- 239000012488 sample solution Substances 0.000 claims abstract description 20
- 238000001514 detection method Methods 0.000 claims abstract description 14
- 238000001816 cooling Methods 0.000 claims abstract description 11
- 238000000967 suction filtration Methods 0.000 claims abstract description 11
- 238000002354 inductively-coupled plasma atomic emission spectroscopy Methods 0.000 claims abstract description 9
- 238000004458 analytical method Methods 0.000 claims abstract description 8
- 238000007789 sealing Methods 0.000 claims abstract description 7
- 238000005303 weighing Methods 0.000 claims abstract description 6
- 229910021642 ultra pure water Inorganic materials 0.000 claims description 11
- 239000012498 ultrapure water Substances 0.000 claims description 11
- 238000012360 testing method Methods 0.000 claims description 9
- 238000000295 emission spectrum Methods 0.000 claims description 7
- 239000000463 material Substances 0.000 claims description 7
- 238000011088 calibration curve Methods 0.000 claims description 6
- 238000007865 diluting Methods 0.000 claims description 6
- 238000010438 heat treatment Methods 0.000 claims description 6
- 239000003755 preservative agent Substances 0.000 claims description 5
- 230000002335 preservative effect Effects 0.000 claims description 5
- 238000012417 linear regression Methods 0.000 claims description 3
- 238000005259 measurement Methods 0.000 claims description 3
- 238000010998 test method Methods 0.000 claims description 3
- 239000013074 reference sample Substances 0.000 claims description 2
- 239000007788 liquid Substances 0.000 claims 2
- 238000007689 inspection Methods 0.000 claims 1
- 239000007774 positive electrode material Substances 0.000 abstract description 9
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 abstract description 4
- 235000011114 ammonium hydroxide Nutrition 0.000 abstract description 2
- 230000008878 coupling Effects 0.000 abstract description 2
- 238000010168 coupling process Methods 0.000 abstract description 2
- 238000005859 coupling reaction Methods 0.000 abstract description 2
- 238000001637 plasma atomic emission spectroscopy Methods 0.000 abstract description 2
- 239000002904 solvent Substances 0.000 abstract description 2
- 238000001914 filtration Methods 0.000 abstract 1
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 8
- 239000002253 acid Substances 0.000 description 6
- 239000011248 coating agent Substances 0.000 description 5
- 238000000576 coating method Methods 0.000 description 5
- 239000003513 alkali Substances 0.000 description 4
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 3
- 229910052783 alkali metal Inorganic materials 0.000 description 3
- 239000013068 control sample Substances 0.000 description 3
- 238000009616 inductively coupled plasma Methods 0.000 description 3
- 229910052744 lithium Inorganic materials 0.000 description 3
- 238000007500 overflow downdraw method Methods 0.000 description 3
- CMPGARWFYBADJI-UHFFFAOYSA-L tungstic acid Chemical compound O[W](O)(=O)=O CMPGARWFYBADJI-UHFFFAOYSA-L 0.000 description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 238000004090 dissolution Methods 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 238000007086 side reaction Methods 0.000 description 2
- 230000003595 spectral effect Effects 0.000 description 2
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- ZMZDMBWJUHKJPS-UHFFFAOYSA-M Thiocyanate anion Chemical compound [S-]C#N ZMZDMBWJUHKJPS-UHFFFAOYSA-M 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 238000003916 acid precipitation Methods 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 239000000498 cooling water Substances 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000001351 cycling effect Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 230000029087 digestion Effects 0.000 description 1
- 238000011978 dissolution method Methods 0.000 description 1
- 239000003792 electrolyte Substances 0.000 description 1
- 238000004993 emission spectroscopy Methods 0.000 description 1
- ZMZDMBWJUHKJPS-UHFFFAOYSA-N hydrogen thiocyanate Natural products SC#N ZMZDMBWJUHKJPS-UHFFFAOYSA-N 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 229910001416 lithium ion Inorganic materials 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000002574 poison Substances 0.000 description 1
- 231100000614 poison Toxicity 0.000 description 1
- 230000010287 polarization Effects 0.000 description 1
- 238000002203 pretreatment Methods 0.000 description 1
- 238000002798 spectrophotometry method Methods 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- 238000004846 x-ray emission Methods 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
- G01N21/71—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light thermally excited
- G01N21/73—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light thermally excited using plasma burners or torches
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
- G01N1/44—Sample treatment involving radiation, e.g. heat
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
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Abstract
The invention relates to the technical field of analysis and detection, in particular to a method for detecting surface tungsten in a ternary positive electrode material, which comprises the following steps of: step 1, preparing a sample solution: accurately weighing a 0.2000g +/-0.0100 g sample in a 50ml beaker, transferring 10 ml-25 ml saturated ammonia water into the beaker, sealing the beaker, dissolving, cooling, fixing the volume to 250ml, and carrying out suction filtration to obtain the product to be tested; step 2, preparing a standard solution series: step 3, measuring the content of tungsten element in the sample solution: filtering insoluble matters in the sample solution, and measuring the content of W in the sample by an ICP-OES method after the sample is separated; the invention adopts ammonia water as solvent to dissolve, then adds water to fix volume, filters, and uses inductance coupling plasma atomic emission spectrometry to measure tungsten element content in sample solution, with reliable result and stable data.
Description
Technical Field
The invention relates to the technical field of analysis and detection, in particular to a method for detecting surface tungsten in a ternary positive electrode material.
Background
The performance of lithium ion batteries currently faces a great challenge, while positive electrode materials have an indispensable role in lithium batteries. By adding a proper amount of tungsten element into the positive electrode material of the lithium battery, the overall structural stability and thermal stability of the positive electrode material can be improved, the occurrence of side reaction can be effectively reduced, and the cycle performance of the material can be improved. The stability improvement of tungsten to the cathode material is mainly achieved by doping or direct coating.
There are particular advantages to the use of W: first, li 2 WO 4 Or Li (lithium) x WO 3 Is a good Li + Conductor, use W coating can form a thin layer of Li on the surface of positive electrode material 2 WO 4 This makes it possible to promote Li + Diffusion, reducing electrochemical polarization, thereby improving rate performance; in addition, direct corrosion experiments have demonstrated that other oxides such as MoO 3 And Nb (Nb) 2 O 5 In contrast, WO 3 Has stronger resistance to HF attack, and thus WO is used 3 Doping and coating can form a W-rich layer on the surface of the positive electrode material, which will reduce side reactions of the electrode/electrolyte to improve structural stability and thus cycle stability, especially during long-term cycling.
It was found that WO is used 3 When coating was performed, 1wt% of the coating was found to have the best performance (cycle stability). The X-ray diffraction results showed that with increasing W content, both the values of c/a (the crystal parameters of the layered structure) and I003/I104 (the intensity ratio of the two major crystal planes in the layered structure) decreased, indicating that the Li/Ni mixture increased because of W 6+ Induce the slave Ni 3+ To Ni 2+ Is a transition of (2). Therefore, it is necessary to control the content of the positive electrode material surface W.
At present, a closed acid melting method and an alkali melting method are generally adopted for pretreatment of tungsten element detection. Wherein, when digestion is carried out on the material sample by an acid dissolution method, li in the sample 2 WO 4 Tungstic acid is produced by the reaction equation: li (Li) 2 WO 4 +2H + =H 2 WO 4 ↓+2H + Because the tungstic acid is only dissolved with hydrofluoric acid and is insoluble in common acid, tungstic acid precipitation can be generated when common acid is adopted, and the detection result is low; when hydrofluoric acid is adopted, because the hydrofluoric acid is extremely strong in corrosiveness and is a highly harmful poison, vapor is inhaled or skin contact can cause burn which is difficult to cure, and the hydrofluoric acid also corrodes instruments, so that the operation is not facilitated; and the alkali fusion method introduces new alkali metal elements in the treatment process, which affects the determination of tungsten elements. In the aspect of testing, the instrument analysis method for tungsten element mainly comprises thiocyanate spectrophotometry, X-ray fluorescence spectrometry, inductively coupled plasma emission spectrometry and the like, wherein the inductively coupled plasma atomic emission spectrometry (ICP-OES) has the advantages of simplicity, rapidness, good data reproducibility, low detection limit and the like.
When the content of the surface W in the sample is measured by the ICP-OES method, how to pretreat the sample in a simple way, so that the difference of results caused by acid dissolution is avoided, and the problem that new alkali metal elements are introduced by the alkali fusion method is also avoided.
Disclosure of Invention
The invention aims to solve the defects in the prior art, and provides a method for detecting surface tungsten in a ternary positive electrode material.
A method for detecting surface tungsten in ternary cathode material comprises the following steps:
step 1, preparing a sample solution:
accurately weighing a 0.2000g +/-0.0100 g sample in a beaker of 50ml, transferring 10 ml-25 ml saturated ammonia water into the beaker, sealing the beaker, placing the beaker in a baking oven at 45-70 ℃ and heating for 15-120 min to fully dissolve soluble matters in the sample, cooling, fixing the volume to 250ml, and carrying out suction filtration to obtain the product to be tested;
step 2, preparing a standard solution series:
firstly, respectively transferring 10mL saturated ammonia water by a liquid-transferring gun in a volumetric flask of 100ml, respectively transferring 0.1ml, 0.2ml and 0.5ml W standard solutions by the liquid-transferring gun in the volumetric flask, diluting to scale marks by ultrapure water, and preparing to obtain a standard solution series;
step 3, measuring the content of tungsten element in the sample solution:
insoluble matter in the sample solution was filtered, and the content of W in the sample was measured by the ICP-OES method after the sample was collected.
Preferably, in the step 1, the beaker is completely covered by a three-layer preservative film, and the beaker is sealed.
Preferably, in the step 1, 10 ml-25 ml saturated ammonia water is removed and added into a beaker, the beaker is sealed, the beaker is placed in an oven at 45-70 ℃ and heated for 15-120 min, after cooling, the volume is fixed to 250ml, suction filtration is carried out, and an empty white control sample is prepared to be tested; in the step 2, in a 100ml volumetric flask, 10mL saturated ammonia water is respectively removed by a pipette, diluted to a scale mark by ultrapure water, and a blank control group is prepared.
Preferably, the W content in the W standard solution is 1000 mug/ml.
Preferably, in the step 3, 4 more sensitive lines 207.911nm, 209.475nm, 224.875nm and 239.709nm of tungsten are selected, and detection is performed at a wavelength corresponding to any one line.
Preferably, in the step 3, the detection is performed in a wavelength range of 207.91nm to 207.92 nm.
Preferably, in the step 3, a calibration curve is determined, the standard solution series of W is measured according to the set working condition of the instrument, the concentration of W in parts per million is on the abscissa, the intensity of the emission spectrum is on the ordinate, the calibration curve of the instrument is drawn, the concentration of W in parts per million is in a linear relation with the emission spectrum when the intensity of W in parts per million is 1ppm to 5ppm, and the linear regression equation is that the correlation coefficient r is 0.999946.
Preferably, in the step 3, after the measurement is completed, the precision test is performed on the sample data: for the method, the content of W in different ternary material samples is measured, the precision analysis is carried out on sample data, a Grabbs test method is adopted on the precision of the sample data, the Grabbs critical value of n=11 and alpha=0.05 is 2.176, G1 and Gn are calculated according to a formula, wherein G1=, gn=, the minimum value of each group of data values is X1, the maximum value is Xn, the standard deviation is S, the average value is the average value, and finally the values of G1 and Gn are compared with the Grabbs critical value, and the analysis result is obtained.
The beneficial effects of the invention are as follows:
1. the invention adopts ammonia water as solvent to dissolve, then adds water to fix volume, filters, and uses inductance coupling plasma atomic emission spectrometry to measure tungsten element content in sample solution, with reliable result and stable data.
2. The pretreatment method is simple and practical, avoids the result difference caused by mixed acid dissolution, simultaneously avoids the problem of introducing new alkali metal elements by an alkali fusion method, is convenient for detection, ensures the accuracy of data, has good data reproducibility, and is suitable for measuring the content of tungsten element in ternary materials.
Detailed Description
The invention is further illustrated below in connection with specific embodiments.
The experimental process adopts an inductively coupled plasma emission spectrometer (Perkinelmer Avio 200), high-purity argon [ omega (Ar) > 99.999% ], and the following table is a main working condition of the inductively coupled plasma emission spectrum.
Table 1 main operating conditions of the instrument
| PerkinElmer Avio 200 | Working conditions |
| Cooling water pump temperature | 20℃ |
| Radio frequency power | 1300 W |
| Radio Frequency (RF) frequency | 40.68 MHz |
| Atomizer flow | 0.7 L/min |
| Observation angle | RADIAL |
| Viewing height of height | 15 mm |
| Analyzing pump speed | 1.5 ml/min |
Main reagent
W standard solution (national iron and steel materials testing center), 1000 μg/mL; the W test standard solution is obtained by diluting a W standard solution, and is respectively 1ppm, 2 ppm and 5 ppm; ammonia (Shanghai microphone Biochemical technology Co., ltd.) is a high grade pure; the experimental water is ultrapure water, and meets the second-level water specified in GB/T6682.
In embodiment 1, a method for detecting surface tungsten in a ternary cathode material includes the following steps:
step 1, preparing a sample solution:
accurately weighing 0.2000g + -0.0100 g sample in a 50ml beaker, and transferring10 mlAdding saturated ammonia water into a beaker, sealing the beaker, and placing the beaker in60℃Heating in an oven15minDissolving soluble substances in the sample sufficiently, cooling, fixing the volume to 250ml, and carrying out suction filtration to obtain a sample to be detected;
step 2, preparing a standard solution series:
firstly, respectively transferring 10mL of saturated ammonia water by a liquid-transferring gun in a volumetric flask of 100mL, respectively transferring 0.1mL of W standard solution, 0.2mL and 0.5mL by the liquid-transferring gun in the volumetric flask, diluting to a scale mark by ultrapure water, and preparing to obtain a standard solution series;
step 3, measuring the content of tungsten element in the sample solution:
insoluble matter in the sample solution was filtered, and the content of W in the sample was measured by the ICP-OES method after the sample was collected.
In the step 1, the beaker is completely covered by three layers of preservative films, and the beaker is sealed.
In the step 1, the moving and taking are carried out10mlAdding saturated ammonia water into a beaker, sealing the beaker, and heating the beaker in a 60 ℃ oven15minCooling, fixing the volume to 250ml, and carrying out suction filtration to obtain a blank control sample to be tested; in the step 2, 10mL saturated ammonia water is respectively removed by a pipette in a 100ml volumetric flask, diluted to a scale mark by ultrapure water, and a blank control group is prepared.
In embodiment 2, a method for detecting surface tungsten in a ternary cathode material includes the following steps:
step 1, preparing a sample solution:
accurately weighing a 0.2000g +/-0.0100 g sample in a beaker of 50ml, transferring 25ml of saturated ammonia water into the beaker, sealing the beaker, placing the beaker in a baking oven at 40 ℃ for heating for 120min to enable soluble matters in the sample to be fully dissolved, cooling, fixing the volume to 250ml, and carrying out suction filtration to obtain the product to be tested;
step 2, preparing a standard solution series:
firstly, respectively transferring 10mL of saturated ammonia water by a liquid-transferring gun in a volumetric flask of 100mL, respectively transferring 0.1mL of W standard solution, 0.2mL and 0.5mL by the liquid-transferring gun in the volumetric flask, diluting to a scale mark by ultrapure water, and preparing to obtain a standard solution series;
step 3, measuring the content of tungsten element in the sample solution:
insoluble matter in the sample solution was filtered, and the content of W in the sample was measured by the ICP-OES method after the sample was collected.
In the step 1, the beaker is completely covered by three layers of preservative films, and the beaker is sealed.
In the step 1, 15 ml saturated ammonia water is removed and added into a beaker, the beaker is sealed, the beaker is placed in a baking oven at 40 ℃ and heated for 120min, the volume is fixed to 250ml after cooling, suction filtration and test are carried out, and a blank control sample is prepared; in the step 2, 10mL saturated ammonia water is respectively removed by a pipette in a 100ml volumetric flask, diluted to a scale mark by ultrapure water, and a blank control group is prepared.
In embodiment 3, a method for detecting surface tungsten in a ternary cathode material includes the following steps:
step 1, preparing a sample solution:
accurately weighing a 0.2000g +/-0.0100 g sample in a beaker of 50ml, transferring 15 ml saturated ammonia water into the beaker, sealing the beaker, placing the beaker in a baking oven of 70 ℃ for heating for 30min to enable soluble matters in the sample to be fully dissolved, cooling, fixing the volume to 250ml, and carrying out suction filtration to obtain the sample to be tested;
step 2, preparing a standard solution series:
firstly, respectively transferring 10mL of saturated ammonia water by a liquid-transferring gun in a volumetric flask of 100mL, respectively transferring 0.1mL of W standard solution, 0.2mL and 0.5mL by the liquid-transferring gun in the volumetric flask, diluting to a scale mark by ultrapure water, and preparing to obtain a standard solution series;
step 3, measuring the content of tungsten element in the sample solution:
insoluble matter in the sample solution was filtered, and the content of W in the sample was measured by the ICP-OES method after the sample was collected.
In the step 1, the beaker is completely covered by three layers of preservative films, and the beaker is sealed.
In the step 1, 15 ml saturated ammonia water is removed and added into a beaker, the beaker is sealed, the beaker is placed in a baking oven at 70 ℃ and heated for 30min, after cooling, the volume is fixed to 250ml, suction filtration and test are carried out, and a blank reference sample is prepared; in the step 2, 10mL saturated ammonia water is respectively removed by a pipette in a 100ml volumetric flask, diluted to a scale mark by ultrapure water, and a blank control group is prepared.
In examples 1 to 3, the W content of the W standard solution was 1000. Mu.g/ml.
In the step 3, 4 more sensitive spectral lines 207.911nm, 209.475nm, 224.875nm and 239.709nm of tungsten are selected, detection is carried out under the wavelength corresponding to any spectral line,
detection is preferably performed in the wavelength range of 207.91nm to 207.92 nm.
In the step 3, a calibration curve is determined, a standard solution series of W is measured according to the set working condition of the instrument, the concentration of the W in parts per million is an abscissa, the intensity of an emission spectrum is an ordinate, the calibration curve of the instrument is drawn, the W in parts per million is in a linear relation with the emission spectrum when the concentration of the W in parts per million is 1ppm to 5ppm, and a linear regression equation is that the correlation coefficient r is 0.999946.
Determining a detection limit: under the same conditions, 10 blank control samples are measured, and the detection limit calculated by taking K=3 is 0.03143 ppm, so that the test requirement can be met.
On the basis of example 1, after the measurement is completed, the precision test is performed on the sample data: for the method, the content of W in different ternary material samples is measured, the precision analysis is carried out on sample data, a Grabbs test method is adopted on the precision of the sample data, the Grabbs critical value of n=11 and alpha=0.05 is 2.176, G1 and Gn are calculated according to a formula, wherein G1=, gn=, the minimum value of each group of data values is X1, the maximum value is Xn, the standard deviation is S, the average value is the average value, and finally the values of G1 and Gn are compared with the Grabbs critical value, and the analysis result is obtained.
TABLE 2 results of W test precision experiments for different samples
The results showed no outliers at all at the 10 different levels measured by this method.
The foregoing is only a preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art, who is within the scope of the present invention, should make equivalent substitutions or modifications according to the technical scheme of the present invention and the inventive concept thereof, and should be covered by the scope of the present invention.
Claims (8)
1. The method for detecting the surface tungsten in the ternary cathode material is characterized by comprising the following steps of:
step 1, preparing a sample solution:
accurately weighing 0.2000 g+/-0.0100 g of sample in a 50ml beaker, transferring 10 ml-25 ml of saturated ammonia water into the beaker, sealing the beaker, placing the beaker in a baking oven at 45-70 ℃ and heating for 15-120 min to fully dissolve soluble matters in the sample, cooling, fixing the volume to 250ml, and carrying out suction filtration to obtain the sample to be tested;
step 2, preparing a standard solution series:
firstly, respectively transferring 10mL of saturated ammonia water by a liquid transfer gun in a 100mL volumetric flask, respectively transferring 0.1mL, 0.2mL and 0.5mL of W standard solution by the liquid transfer gun in the volumetric flask, diluting to a scale mark by ultrapure water, and preparing to obtain a standard solution series;
step 3, measuring the content of tungsten element in the sample solution:
insoluble matter in the sample solution was filtered, and the content of W in the sample was measured by the ICP-OES method after the sample was collected.
2. The method for detecting surface tungsten in a ternary cathode material according to claim 1, wherein in the step 1, the beaker is completely covered by a three-layer preservative film, and is sealed.
3. The method for detecting surface tungsten in a ternary cathode material according to claim 1, wherein in the step 1, 10 ml-25 ml of saturated ammonia water is removed and added into a beaker, the beaker is sealed, the beaker is placed in a 60 ℃ oven and heated for 15 min-120 min, after cooling, the volume is fixed to 250ml, and suction filtration and test are carried out, so that a blank reference sample is prepared; in the step 2, 10mL of saturated ammonia water is respectively removed by a liquid-transferring gun in a 100mL volumetric flask, and diluted to a scale mark by ultrapure water to prepare a blank control group.
4. The method for detecting surface tungsten in a ternary cathode material according to claim 1, wherein the content of W in the W standard solution is 1000 mug/ml.
5. The method for detecting surface tungsten in ternary cathode material according to claim 1, wherein in the step 3, 4 relatively sensitive lines 207.911nm, 209.475nm, 224.875nm and 239.709nm of tungsten are selected, and detection is performed at a wavelength corresponding to any one line.
6. The method for detecting surface tungsten in a ternary cathode material according to claim 1, wherein in the step 3, detection is performed in a wavelength range of 207.91nm to 207.92 nm.
7. The method for detecting surface tungsten in ternary cathode material according to claim 1, wherein in the step 3, a calibration curve is determined, a standard solution series of W is measured according to set working conditions of an instrument, the concentration of W in parts per million is on an abscissa, the intensity of an emission spectrum is on an ordinate, the calibration curve of the instrument is drawn, the concentration of W in parts per million is in a linear relation with the emission spectrum at 1ppm to 5ppm, a linear regression equation is y= 445.62x-13.326, and a correlation coefficient r is 0.999946.
8. The method for detecting surface tungsten in ternary cathode material according to any one of claims 1-7, wherein in step 3, after the measurement is completed, precision inspection is performed on sample data: for the method to determine the W content in different ternary material samples, performing precision analysis on sample data, adopting a Grabbs test method on the precision of the sample data, taking a Grabbs critical value of n=11 and alpha=0.05 as 2.176, and calculating G1 and Gn according to a formula, wherein the method comprises the following steps of
The minimum value of each group of data values is X1, the maximum value of each group of data values is Xn, the standard deviation of each group of data values is S, the average value of each group of data values is X, and finally the values of G1 and Gn are compared with the Grabbs critical value for analysisAs a result.
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| CN202211671675.XA CN116359205A (en) | 2022-12-26 | 2022-12-26 | Method for detecting surface tungsten in ternary cathode material |
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