CN112798630A - Sample preparation method for representing element distribution uniformity - Google Patents
Sample preparation method for representing element distribution uniformity Download PDFInfo
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- CN112798630A CN112798630A CN201911107732.XA CN201911107732A CN112798630A CN 112798630 A CN112798630 A CN 112798630A CN 201911107732 A CN201911107732 A CN 201911107732A CN 112798630 A CN112798630 A CN 112798630A
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- 238000009826 distribution Methods 0.000 title claims abstract description 36
- 238000005464 sample preparation method Methods 0.000 title claims abstract description 11
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims abstract description 54
- 238000010884 ion-beam technique Methods 0.000 claims abstract description 51
- 239000007774 positive electrode material Substances 0.000 claims abstract description 38
- 238000005520 cutting process Methods 0.000 claims abstract description 29
- 229910052786 argon Inorganic materials 0.000 claims abstract description 27
- 238000000034 method Methods 0.000 claims abstract description 22
- 238000012360 testing method Methods 0.000 claims abstract description 15
- 239000011248 coating agent Substances 0.000 claims description 20
- 238000000576 coating method Methods 0.000 claims description 20
- 239000002002 slurry Substances 0.000 claims description 19
- 239000011230 binding agent Substances 0.000 claims description 17
- 239000003960 organic solvent Substances 0.000 claims description 10
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 9
- 229910052782 aluminium Inorganic materials 0.000 claims description 9
- 239000011888 foil Substances 0.000 claims description 9
- 238000002360 preparation method Methods 0.000 claims description 9
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 8
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical group [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 6
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 6
- 239000011889 copper foil Substances 0.000 claims description 6
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims description 5
- 229910052744 lithium Inorganic materials 0.000 claims description 5
- 239000007788 liquid Substances 0.000 claims description 4
- 229910052757 nitrogen Inorganic materials 0.000 claims description 4
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 3
- 238000002156 mixing Methods 0.000 claims description 3
- 229910052759 nickel Inorganic materials 0.000 claims description 3
- 238000004458 analytical method Methods 0.000 abstract description 2
- 239000010405 anode material Substances 0.000 description 14
- 239000000463 material Substances 0.000 description 13
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- 239000002033 PVDF binder Substances 0.000 description 4
- 238000012512 characterization method Methods 0.000 description 4
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 4
- 239000007787 solid Substances 0.000 description 4
- WEVYAHXRMPXWCK-UHFFFAOYSA-N Acetonitrile Chemical compound CC#N WEVYAHXRMPXWCK-UHFFFAOYSA-N 0.000 description 3
- 238000005253 cladding Methods 0.000 description 3
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- 230000000694 effects Effects 0.000 description 3
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- 238000005303 weighing Methods 0.000 description 3
- WYURNTSHIVDZCO-UHFFFAOYSA-N Tetrahydrofuran Chemical compound C1CCOC1 WYURNTSHIVDZCO-UHFFFAOYSA-N 0.000 description 2
- 239000013543 active substance Substances 0.000 description 2
- 238000007580 dry-mixing Methods 0.000 description 2
- 238000000724 energy-dispersive X-ray spectrum Methods 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
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- 238000004611 spectroscopical analysis Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 239000004372 Polyvinyl alcohol Substances 0.000 description 1
- KFDQGLPGKXUTMZ-UHFFFAOYSA-N [Mn].[Co].[Ni] Chemical compound [Mn].[Co].[Ni] KFDQGLPGKXUTMZ-UHFFFAOYSA-N 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
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- 238000002186 photoelectron spectrum Methods 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- 229920000098 polyolefin Polymers 0.000 description 1
- -1 polytetrafluoroethylene Polymers 0.000 description 1
- 239000004810 polytetrafluoroethylene Substances 0.000 description 1
- 229920001343 polytetrafluoroethylene Polymers 0.000 description 1
- 229920002635 polyurethane Polymers 0.000 description 1
- 239000004814 polyurethane Substances 0.000 description 1
- 229920002451 polyvinyl alcohol Polymers 0.000 description 1
- 239000011164 primary particle Substances 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 238000004537 pulping Methods 0.000 description 1
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- 239000005060 rubber Substances 0.000 description 1
- 235000019812 sodium carboxymethyl cellulose Nutrition 0.000 description 1
- 229920001027 sodium carboxymethylcellulose Polymers 0.000 description 1
- PUZPDOWCWNUUKD-UHFFFAOYSA-M sodium fluoride Chemical compound [F-].[Na+] PUZPDOWCWNUUKD-UHFFFAOYSA-M 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 229920003048 styrene butadiene rubber Polymers 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 239000002344 surface layer Substances 0.000 description 1
- YLQBMQCUIZJEEH-UHFFFAOYSA-N tetrahydrofuran Natural products C=1C=COC=1 YLQBMQCUIZJEEH-UHFFFAOYSA-N 0.000 description 1
- 238000001132 ultrasonic dispersion 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
- G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
- G01N23/22—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by measuring secondary emission from the material
- G01N23/2202—Preparing specimens therefor
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
- G01N23/22—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by measuring secondary emission from the material
- G01N23/225—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by measuring secondary emission from the material using electron or ion
- G01N23/2251—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by measuring secondary emission from the material using electron or ion using incident electron beams, e.g. scanning electron microscopy [SEM]
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/139—Processes of manufacture
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- G—PHYSICS
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Abstract
The invention discloses a sample preparation method for representing element uniformity of a positive electrode material, which comprises the following steps: step 1, preparing a positive electrode material and preparing a positive electrode piece; step 2, cutting the positive pole piece to form a cut section; and 3, testing the cut section. The section of the formed positive pole piece is used for electron microscope test analysis by preparing the positive pole piece and cutting the positive pole piece by adopting argon ion beams. The method provided by the invention is simple and rapid, and can obtain the element distribution condition more intuitively.
Description
Technical Field
The invention belongs to the technical field of material characterization, and particularly relates to a sample preparation method for characterizing element distribution uniformity.
Background
The lithium ion battery is one of main power sources of 3C consumer electronics and electric automobiles, and has the advantages of high energy density, high safety performance, low self-discharge and the like. As an important component of the battery, the positive electrode material of the lithium ion battery plays a key role in improving the energy density of the battery.
The anode materials used at present, such as lithium cobaltate, ternary materials and the like, adopt element doping and cladding to achieve the purpose of improving the performance. In the field of preparation of lithium ion battery anode materials, element doping and coating are generally realized by adopting dry mixing, but whether the effects of doping and coating uniformity are achieved cannot be known. The uniformity of element distribution has a key influence on the physical, chemical and electrochemical properties of the material, so that the accurate characterization of element doping and coating uniformity plays a crucial role.
At present, element doping uniformity is generally characterized by an energy spectrum of a test element, but the method is only limited to the surface layer of particles, the resolution is low, and the distribution uniformity of a certain element cannot be accurately judged for some elements with similar energy. In addition, the photoelectron spectrum and the electron energy loss spectrum have a certain effect on the identification of the element species with a surface of several hundred nanometers and the characterization of the distribution uniformity, but are slightly insufficient in the characterization of the bulk element uniformity. Therefore, the method has profound significance for simultaneously characterizing the distribution uniformity of the elements on the surface and in the bulk phase of the material.
Disclosure of Invention
In order to overcome the above problems, the present inventors have conducted intensive studies to develop a sample preparation method for characterizing element uniformity of a positive electrode material, the method comprising: preparing a positive electrode material and preparing a positive electrode piece; step 2, cutting the positive pole piece to form a cut section; and 3, testing the cut section. The method provided by the invention is simple and rapid, and can obtain element distribution conditions more intuitively, thereby completing the method.
The invention aims to provide a sample preparation method for characterizing element distribution uniformity in a positive electrode material, which comprises the following steps:
step 1, preparing a positive electrode material and preparing a positive electrode piece;
step 2, cutting the positive pole piece to form a cut section;
and 3, testing the cut section.
In the step 2, the positive pole piece is cut by adopting an argon ion beam, and the formed section of the positive pole piece is used for electron microscope test analysis.
The preparation of the positive pole piece comprises the following steps: mixing a positive electrode material, a binder and an organic solvent to obtain slurry; and coating the slurry on a carrier to obtain the positive pole piece.
The positive electrode material is selected from a lithium cobaltate positive electrode material or a ternary positive electrode material; the mass ratio of the positive electrode material to the binder is (60-98): (2-40), wherein the mass ratio of the sum of the mass of the positive electrode material and the binder to the organic solvent is (65-95): 100,
the carrier is copper foil, aluminum foil, titanium foil, foamed nickel or a diaphragm, and preferably copper foil or aluminum foil.
In the step 2, the positive pole piece is fixed on a sample table clamp, and the positive pole piece is cut by adopting argon ion beams to obtain a cut section of the positive pole piece.
In the step 2, three beams of argon ion beams are adopted to cut the positive pole piece, wherein in the three beams of argon ion beams, a middle ion beam is vertical to the pole piece sample, and the other two beams are respectively positioned at two sides of the middle ion beam and form an included angle of 30-60 degrees with the middle ion beam; the three beams of argon ion beams are distributed in a fan shape on a plane vertical to the anode pole piece, and the included angles between the other two beams of argon ion beams and the middle ion beam are both 60 degrees. The polishable angle of the argon ion beam is in the range of 10 to 90 deg..
In the step 2, the overall temperature of the sample stage is controlled to be lower than 40 ℃ in the cutting process.
And in the step 2, the liquid nitrogen is adopted to cool the sample table so as to control the overall temperature of the sample table.
The invention has the following beneficial effects:
(1) the method adopts argon ion beams to cut the positive pole piece, and obtains the distribution conditions of main elements and doping elements on the surface and in bulk phase of the positive pole material in the positive pole piece through energy spectrum scanning;
(2) the method can obtain the element distribution uniformity on the surface of the positive electrode material in the positive electrode plate and in the bulk phase, thereby providing a reliable basis for evaluating the performance of the positive electrode material;
(3) the method provided by the invention solves the problem that the uniformity of the distribution of the elements in the characterized bulk phase is insufficient in the prior art;
(4) the preparation method of the anode material section sample provided by the invention is simple and convenient, and the preparation efficiency and the section quality of the sample section are improved.
Drawings
FIG. 1 shows an SEM image and an EDS spectrum of a cross-sectional sample obtained in example 1 of the present invention;
FIG. 2 shows an SEM image and an EDS spectrum of a cross-sectional sample obtained in example 2 of the present invention.
Detailed Description
The invention is explained in more detail below with reference to the drawings and preferred embodiments. The features and advantages of the present invention will become more apparent from the description.
According to the invention, a sample preparation method for characterizing element distribution uniformity of a positive electrode material is provided, and the method comprises the following steps:
step 1, preparing a positive electrode material and preparing a positive electrode piece.
In the invention, in the field of lithium ion batteries, the anode material plays a key role in the electrochemical performance of the lithium ion batteries, the anode material is usually obtained by element doping or coating by dry mixing, and the distribution uniformity of doped or coated elements in the anode material has an important influence on the electrochemical performance of the anode material.
According to the invention, the distribution uniformity of the bulk phase elements in the positive electrode material can be obtained by manufacturing the positive electrode material into a pole piece, cutting the pole piece to obtain the distribution condition of the elements on the section through electron microscope and energy spectrum tests of the cut section, and cutting the pole piece in a plurality of different directions to obtain the distribution condition of the elements on a plurality of different cut sections, so that the distribution condition of the bulk phase elements is obtained, and the performance of the positive electrode material can be evaluated according to the distribution condition.
According to the invention, in step 1, preparing a positive electrode material and preparing a positive electrode piece, wherein the preparation of the positive electrode piece comprises the following steps: mixing a positive electrode material, a binder and an organic solvent to obtain slurry; and coating the slurry on a carrier to obtain the positive pole piece.
According to the invention, in step 1, the positive electrode material is a positive electrode material in a lithium ion battery, preferably a lithium cobaltate positive electrode material, a ternary positive electrode material, and the like.
According to the present invention, the positive electrode material includes a main element, and preferably further includes a dopant element and/or a cladding element.
In the present invention, the uniformity of the doping element or the cladding element in the positive electrode material can be observed by SEM-EDS spectroscopy. The distribution uniformity of the doping elements and the coating elements in the cathode material comprises the distribution conditions of the surface and the bulk phase, the distribution uniformity of the surface elements can be obtained by observing the surface of the cathode material, and the bulk phase of the cathode material can be observed by placing the cathode material on a carrier.
According to the invention, the positive pole piece is prepared from the positive pole material and is used for testing. The positive pole piece is adopted as a sample for testing the positive pole material, and the preparation of the positive pole piece can greatly simplify the steps of the conventional solid sample preparation method and shorten the sample preparation time.
According to the invention, the binder is selected from one or more of polyvinyl alcohol, polytetrafluoroethylene, polyvinylidene fluoride, sodium carboxymethyl cellulose, polyolefins, polyurethane, styrene butadiene rubber, fluorinated rubber and the like, and is preferably polyvinylidene fluoride. The addition of the binder not only has a binding effect between active substance particles, but also ensures the adhesion of the active substance on the current collector, and is beneficial to improving the uniformity and the safety in the pulping process.
In the invention, the lithium ion battery obtained by using the binder, especially polyvinylidene fluoride as the binder has high specific capacity and high chemical stability.
According to a preferred embodiment of the present invention, the mass ratio of the positive electrode material to the binder is (60-98): (2-40).
According to the invention, the organic solvent is one or more selected from N-methyl pyrrolidone, tetrahydrofuran, acetonitrile and the like, and N-methyl pyrrolidone is preferred.
According to the present invention, the slurry solid content (i.e., the mass ratio of the sum of the masses of the positive electrode material and the binder to the organic solvent) is 65% to 95%, preferably 70 to 80%. If the solid content is too high, the viscosity of the slurry is higher, which is not beneficial to the later smear; if the solid content is too low, the corresponding particles of the material under an electron microscope are too small, and the taken electron microscope photo is not representative.
According to the present invention, in step 1, the positive electrode material, the binder and the organic solvent are mixed, preferably by stirring, to obtain a slurry.
According to a preferred embodiment of the present invention, the binder is dispersed in the organic solvent in a manner not particularly limited, preferably by ultrasonic dispersion at a power of 50 to 100Hz for a time of 0.25 to 3 hours; and then adding the anode material into the solution, and stirring to obtain mixed slurry, wherein the stirring speed is 1500-2500 r/min, preferably 2000r/min, and the stirring time is 5-30 min, preferably 5-15 min.
According to the invention, after the slurry is obtained, the slurry is uniformly coated on the carrier, and then the carrier coated with the slurry is dried for later use.
According to the present invention, the coating is preferably performed using an electric coater, and the coating amount or coating thickness is controlled within the range of 150-250 μm. If the coating thickness is too thick, more particles are observed under the same times, and the phenomena of dense particle accumulation and the like can exist, which are not beneficial to later-stage observation; too thin a coating thickness results in fewer particles in the field of view, requiring careful selection and is time consuming.
According to the invention, the carrier is selected from one or more of copper foil, aluminum foil, titanium foil, foamed nickel, diaphragm and the like, and is preferably copper foil or aluminum foil.
In the invention, the carrier coated with the slurry needs to be dried to remove the organic solvent in the slurry, and the drying temperature is related to the boiling point of the solvent and the heat resistance of the carrier.
According to an embodiment of the present invention, the drying is preferably performed in a forced air drying oven, the drying temperature is 50 to 80 ℃, the drying time is 4 to 10 hours, and preferably, the drying temperature is 60 ℃.
According to the invention, the positive pole piece is obtained after the carrier coated with the slurry is dried, and the positive pole piece is cut into a proper shape and size to be arranged on a sample table clamp for ion beam cutting.
According to the invention, the positive pole piece with a certain shape is prepared from the positive pole material, and then the positive pole piece is cut, so that the element distribution of the positive pole material cutting surface in the positive pole piece can be conveniently observed, and the preparation process of the prepared positive pole piece is similar to that of the pole piece of the lithium ion battery.
According to the invention, the positive pole piece can be circular pole pieces with various radiuses or square pole pieces with various lengths.
And 2, cutting the positive pole piece to form a cut section.
According to the invention, in the step 2, the argon ion beam is adopted to cut the positive pole piece, so that the problem of uneven cutting surface caused by a mechanical cutting mode can be avoided, the processing time of focused ion beam FIB can be effectively shortened, and the cost is reduced. Accordingly, argon ion beam cutting techniques may be considered as the best option for obtaining stress damage and contamination free flat profiles with high efficiency and low cost.
In the invention, when the argon ion beam is adopted to cut the positive pole piece, heat can be generated, so that the heat conducting property of a sample is improved, the temperature of the positive pole piece is increased, the temperature is too high, and the negative influence is generated on the positive pole material and the carrier in the positive pole piece.
According to the invention, the positive pole piece is fixed on the sample table clamp, the cavity is vacuumized, and the sample table is cooled at the same time, preferably, the sample table is cooled by filling liquid nitrogen to cool the sample table, so as to balance the temperature of the cavity which rises suddenly during cutting.
According to the invention, because the hot melting temperature of the current collector of the polymer material such as the diaphragm is lower, the phenomena of rolling and even melting can exist under the cutting of high ion beams, and the temperature of the sample stage is required to be controlled below 40 ℃, thereby realizing the normal temperature processing of the polymer material such as the diaphragm.
According to the invention, the positive pole piece is cut by adopting the ion beam to obtain the cut section of the positive pole piece, and preferably, three beams of argon ion beams are adopted for cutting in different directions. The argon ion beam was provided by an argon ion beam cutter model Leica EM TIC 3X.
According to the invention, the operation interface is set as follows: adjusting the appropriate Ar gas flow (0-1), firstly setting the voltage to be 4-6kV, the grinding time to be 1-5h, then setting the voltage to be 1-2kV, the grinding time to be 1-5h, and starting grinding by clicking.
According to the invention, the ion beam current can reach 10mA/cm2Preferably 3-6mA/cm2The polishing speed can reach 300 mu m/h, preferably 50-150 mu m/h.
According to the invention, when three beams of argon ion beams are used for cutting, the middle ion beam is perpendicular to the anode plate sample, and the other two beams are respectively positioned at two sides of the middle ion beam and form an included angle of 30-60 degrees with the middle ion beam, preferably 60 degrees.
According to the invention, three argon ion beams are distributed in a fan shape on a plane vertical to the anode pole piece, and the polishable angle range of the argon ion beams is 10-90 degrees.
And 3, testing the cutting surface.
According to the invention, after the cut section of the positive pole piece is obtained in the step 3, the cut section can be tested through SEM-EDS, and the element distribution condition on the cut section is tested to obtain the element distribution uniformity. For example, the distribution uniformity of the doping elements and/or the coating elements in the cathode material on the cut section is obtained through an EDS (electron-discharge spectroscopy), and the distribution uniformity of the obtained elements can be used as a basis for evaluating the performance of the cathode material. The doping elements and/or the coating elements are uniformly distributed in the anode material, and the obtained anode material has high specific capacity and good cycle performance.
According to the sample preparation method for representing the element distribution uniformity in the anode material, provided by the invention, the anode pole piece is cut by adopting the ion beam, the three beams of argon ion beams are used for cutting in different directions to obtain the section of the pole piece, and the distribution uniformity degree of the element in the anode material body phase is obtained through electron microscope test and energy spectrum test of the section, so that the distribution uniformity degree can be used as a reliable basis for evaluating the performance of the anode material.
The sample preparation method for characterizing the distribution uniformity of the elements can be applied to other materials and used for testing the distribution uniformity of the doping elements of other materials, and the method has wide application range.
Examples
Example 1
Weighing 6.25g of binder PVDF, dispersing into 2.4g of N-methyl pyrrolidone, weighing 9.5g of nickel-cobalt-manganese anode material, adding into the solution, and uniformly stirring to obtain slurry;
coating the slurry on an aluminum foil through an electric coating machine, and drying in a 60 ℃ drying oven to obtain a positive pole piece for later use;
cutting the positive pole piece into 8 × 8cm square pole pieces;
fixing the square pole piece on a sample table clamp, and controlling the temperature of the sample table to be 25 ℃ by utilizing liquid nitrogen so as to balance the temperature of a cavity suddenly rising during cutting;
cutting the positive pole piece by adopting three beams of argon ion beams, wherein the middle ion beam is vertical to the positive pole piece, the other two beams are respectively positioned at two sides of the middle ion beam and form an included angle of 60 degrees with the middle ion beam, adjusting the appropriate Ar gas flow (0-1), firstly setting the voltage of 4kV, grinding time of 2h, then setting the voltage of 2kV, grinding time of 2h, starting to grind by clicking, and cutting the pole piece;
taking down the cut pole piece, fixing the cut surface upward on a sample stage of a scanning electron microscope, and performing energy spectrum surface scanning on the main element and the doped element, wherein an SEM image of the obtained sample is shown as figure 1, wherein figure 1(a) is an SEM image of a cross section, figure 1(b) is an EDS energy spectrum of the main element, and figure 1(c) is an EDS energy spectrum of the doped element.
As can be seen from fig. 1, the cathode material is formed by aggregating a plurality of primary particles, the distribution of the main element is uniform, the distribution of the doping element is relatively uniform, but the doping element is partially enriched on the surface, which indicates that the doping agent is not uniformly mixed, so that the doping element is enriched on the surface, which is not beneficial to the improvement of the electrochemical performance of the cathode material.
Example 2
Weighing 1.5g of binder, dispersing into 2.9g of N-methyl pyrrolidone, adding 9.88g of lithium cobaltate cathode material into the solution, and stirring to obtain slurry;
uniformly coating the slurry on an aluminum foil through an electric coating machine, and then placing the aluminum foil in a 60 ℃ drying oven for drying to obtain a positive pole piece for later use;
cutting the positive pole piece into a wafer with the diameter of 15mm for later use;
fixing the wafer on a sample table clamp, controlling the temperature of the sample table to be 25 ℃ so as to balance the temperature of the cavity suddenly rising during cutting,
cutting the positive pole piece by adopting three beams of argon ion beams, wherein the middle ion beam is vertical to the positive pole piece, the other two beams are respectively positioned at two sides of the middle ion beam and form an included angle of 60 degrees with the middle ion beam, adjusting the appropriate Ar gas flow (0-1), firstly setting the voltage of 4kV, grinding the wafer for 3 hours, then setting the voltage of 1kV, grinding the wafer for 2 hours, and starting to cut the ion beams on the wafer by clicking;
and (3) taking down the cut pole piece, enabling the cutting surface to face upwards, fixing the pole piece on a sample table of a scanning electron microscope by using conductive adhesive, and carrying out scanning electron microscope test to obtain an SEM image as shown in figure 2. Wherein fig. 2(a) is an SEM image of a cross section, fig. 2(b) is an EDS energy spectrum of a main element, and fig. 2(c) is an EDS energy spectrum of a dopant element.
As can be seen from fig. 2, the main element and the doping element are uniformly distributed without enrichment, which indicates that the elements are uniformly distributed regardless of bulk phase doping or surface coating.
The invention has been described in detail with reference to the preferred embodiments and illustrative examples. It should be noted, however, that these specific embodiments are only illustrative of the present invention and do not limit the scope of the present invention in any way. Various modifications, equivalent substitutions and alterations can be made to the technical content and embodiments of the present invention without departing from the spirit and scope of the present invention, and these are within the scope of the present invention. The scope of the invention is defined by the appended claims.
Claims (10)
1. A sample preparation method for characterizing element distribution uniformity is characterized by comprising the following steps:
step 1, preparing a positive electrode material and preparing a positive electrode piece;
step 2, cutting the positive pole piece to form a cut section;
and 3, testing the cut section.
2. The method of claim 1, wherein in step 2, the positive pole piece is cut by an argon ion beam.
3. The method according to claim 1, wherein in step 1, the preparation of the positive electrode plate comprises: mixing a positive electrode material, a binder and an organic solvent to obtain slurry; and coating the slurry on a carrier to obtain the positive pole piece.
4. The method according to claim 3, wherein the positive electrode material is selected from a lithium cobaltate positive electrode material or a ternary positive electrode material; the mass ratio of the positive electrode material to the binder is (60-98): (2-40), wherein the mass ratio of the sum of the mass of the positive electrode material and the binder to the organic solvent is (65-95): 100,
the carrier is copper foil, aluminum foil, titanium foil, foamed nickel or a diaphragm, and preferably copper foil or aluminum foil.
5. The method according to claim 2, wherein in the step 2, the positive pole piece is fixed on a sample stage clamp, and the positive pole piece is cut by adopting an argon ion beam to obtain a cut section of the positive pole piece.
6. The method as claimed in claim 4, wherein in the step 2, the positive electrode plate is cut by using three beams of argon ion beams, wherein the middle ion beam is perpendicular to the positive electrode plate, and the other two beams are respectively located at two sides of the middle ion beam and form an included angle of 30-60 degrees with the middle ion beam.
7. The method of claim 6, wherein the three argon ion beams are fan-shaped on a plane perpendicular to the anode plate, and the other two argon ion beams are both at an angle of 60 ° with respect to the intermediate ion beam.
8. The method of claim 7, wherein the polishable angle of the argon ion beam is in the range of 10-90 °.
9. The method of claim 5, wherein in step 2, the overall temperature of the sample stage is controlled to be less than 40 ℃ during the cutting process.
10. The method according to claim 4, wherein in step 2, the temperature of the sample stage is reduced by using liquid nitrogen to control the overall temperature of the sample stage.
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Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN113865915A (en) * | 2021-09-18 | 2021-12-31 | 长江存储科技有限责任公司 | Detection method of sliced sample |
Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2012078096A (en) * | 2010-09-30 | 2012-04-19 | Sumitomo Metal Mining Co Ltd | Sample preparation method for electron microscope observation and sample for electron microscope observation |
US20120282525A1 (en) * | 2009-12-02 | 2012-11-08 | Hiroki Nagai | Active material particles and use of same |
CN103779536A (en) * | 2013-11-06 | 2014-05-07 | 南京安普瑞斯有限公司 | Silicon-containing negative electrode of lithium ion battery and preparation method of silicon-containing negative electrode |
JP2017111958A (en) * | 2015-12-16 | 2017-06-22 | 昭和電工株式会社 | Negative electrode for lithium ion secondary battery |
CN107507958A (en) * | 2017-07-17 | 2017-12-22 | 河南师范大学 | A kind of powder in situ cladding for lithium-sulfur cell prepares integral method with pole plate |
CN107591563A (en) * | 2016-07-07 | 2018-01-16 | 中国科学院物理研究所 | A kind of sulfenyl electrolyte solution and its application in solid state lithium battery |
CN108807982A (en) * | 2018-07-10 | 2018-11-13 | 江西星盈科技有限公司 | A kind of making formula of the positive electrode of high compacted density |
-
2019
- 2019-11-13 CN CN201911107732.XA patent/CN112798630A/en active Pending
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20120282525A1 (en) * | 2009-12-02 | 2012-11-08 | Hiroki Nagai | Active material particles and use of same |
JP2012078096A (en) * | 2010-09-30 | 2012-04-19 | Sumitomo Metal Mining Co Ltd | Sample preparation method for electron microscope observation and sample for electron microscope observation |
CN103779536A (en) * | 2013-11-06 | 2014-05-07 | 南京安普瑞斯有限公司 | Silicon-containing negative electrode of lithium ion battery and preparation method of silicon-containing negative electrode |
JP2017111958A (en) * | 2015-12-16 | 2017-06-22 | 昭和電工株式会社 | Negative electrode for lithium ion secondary battery |
CN107591563A (en) * | 2016-07-07 | 2018-01-16 | 中国科学院物理研究所 | A kind of sulfenyl electrolyte solution and its application in solid state lithium battery |
CN107507958A (en) * | 2017-07-17 | 2017-12-22 | 河南师范大学 | A kind of powder in situ cladding for lithium-sulfur cell prepares integral method with pole plate |
CN108807982A (en) * | 2018-07-10 | 2018-11-13 | 江西星盈科技有限公司 | A kind of making formula of the positive electrode of high compacted density |
Non-Patent Citations (1)
Title |
---|
MADHAV SINGH等: "Thick Electrodes for High Energy Lithium Ion Batteries", 《JOURNAL OF THE ELECTROCHEMICAL SOCIETY》 * |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN113865915A (en) * | 2021-09-18 | 2021-12-31 | 长江存储科技有限责任公司 | Detection method of sliced sample |
CN113865915B (en) * | 2021-09-18 | 2023-10-13 | 长江存储科技有限责任公司 | Slice sample detection method |
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