Method for solid-phase synthesis of oxide positive electrode material based on electron beam heating and material
Through the solid phase synthesis method of electron beam heating, the existing high-temperature oxidized cathode materials are solved, and the rapid and batch production of high-specific capacity oxide cathode materials, especially high-entropy materials, is achieved, which improves the specific capacity and controls the local structure.
Patent Information
- Application Number
- CN202510440255.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-09
- Publication Date
- 2025-08-26
AI Technical Summary
The existing methods for preparing oxidized cathode materials at high temperatures are energy-consuming, costly, and are prone to light element losses and lead to specific capacity losses. The existing alternative methods such as flash burning, microwave heating and Joule heating are not suitable for mass production.
The solid phase synthesis method of electron beam heating is adopted to control the voltage, current, scanning time interval and scanning rate of the electron beam to achieve rapid preparation in seconds or minutes, which is suitable for large-scale production.
It realizes efficient and rapid preparation of oxide positive electrode materials, maintains high specific capacity, and is suitable for mass production, especially high entropy materials, which improves specific capacity and controls local structure.
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Figure CN120535014A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of oxide positive electrode material preparation, and in particular to a method and material for solid-phase synthesis of oxide positive electrode materials based on electron beam heating. Background Art
[0002] Oxide cathode materials are one of the key factors determining the energy density of secondary batteries. The development of cathode materials with high specific capacity and a wide voltage window, as well as innovations in their preparation methods, can drive the development of secondary batteries. However, currently, high-capacity cathode materials, such as ternary materials and high-entropy disordered rock salt phases, often require heating temperatures exceeding 1000°C and holding times of several or even dozens of hours, significantly increasing energy consumption and raising both the material's preparation and R&D costs. Furthermore, prolonged high-temperature treatment can easily lead to the loss of light elements in the material, such as Li, F, and O, resulting in the formation of impurity phases and a loss of specific capacity.
[0003] Therefore, in the exploration of new high-temperature preparation methods, researchers have developed methods such as flash calcination, microwave heating, and Joule heating, which can raise temperatures to thousands of degrees in a very short time, thereby improving preparation efficiency. However, these methods are not conducive to mass production. For example, flash calcination requires customized molds and high pressure, Joule heating requires high voltage and high current, and the preparation of multiple samples depends on energy supply equipment. Microwave heating is prone to uneven heating due to the thickness and depth of the sample itself.
[0004] The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. Summary of the Invention
[0005] The present invention provides a method and material for solid-phase synthesis of oxide positive electrode materials based on electron beam heating, which improves the heating rate and reduces the heating time to achieve preparation in seconds or minutes. At the same time, large-scale preparation can be achieved, and the samples do not require additional supports or molds.
[0006] A method for solid-phase synthesis of oxide cathode materials based on electron beam heating includes:
[0007] Step 1: The precursor powder of the positive electrode material is mixed uniformly to form a green body;
[0008] Step 2: Wrap the green body in graphite paper to form a sample, and place it on a sample stage;
[0009] Step 3, turning on the electron beam and scanning the sample with the electron beam to heat it, wherein the heating rate and temperature are controlled by the voltage, current, scanning time interval and scanning rate of the electron beam;
[0010] Step 4: Grind the heated sample into powder to obtain a positive electrode material.
[0011] In the method for solid-phase synthesis of oxide positive electrode materials based on electron beam heating, in step 1, the precursor powders are mixed based on the stoichiometric ratio of the positive electrode material of the final product.
[0012] In the method for solid-phase synthesis of oxide positive electrode materials based on electron beam heating, in step 1, the precursor powder includes lithium fluoride or lithium carbonate, and the amount of the precursor powder is additionally added by 5%-20%.
[0013] In the method for solid-phase synthesis of oxide positive electrode materials based on electron beam heating, the precursor powders are mixed by sampling ball milling and a tablet press is used to form a green embryo, and the thickness of the green embryo is between 500 microns and 2 mm.
[0014] In the method for solid-phase synthesis of oxide positive electrode materials based on electron beam heating, graphite paper is replaced by graphite felt or porous graphite layer.
[0015] In the method for solid-phase synthesis of oxide positive electrode materials based on electron beam heating, the thickness of the graphite paper is 1 micron to 3 millimeters.
[0016] In the method of solid-phase synthesis of oxide positive electrode materials based on electron beam heating, the electron beam is used as a heat source, and high-speed electrons are used to collide with atoms in the sample / heat transfer medium lattice, generating lattice vibration for heating and achieving heat input.
[0017] In the method for solid-phase synthesis of oxide positive electrode materials based on electron beam heating, the voltage of the electron beam is 10 to 100 keV and the current is 5 to 100 mA.
[0018] A solid-phase synthesized oxide positive electrode material is prepared via the method.
[0019] A solid-phase synthesized oxide positive electrode material, wherein the solid-phase synthesized oxide positive electrode material includes a high entropy cation disordered salt rock positive electrode, a sodium superion conductor (NASICON) structural material, Li7La3Zr2O 12 Solid-state electrolytes, high-entropy ceramic materials.
[0020] Compared with existing technologies, the present invention has the following advantages: High preparation efficiency. The method provided by the present invention can achieve minute-level preparation of cathode materials and can also achieve mass production. The prepared high-entropy cationic disordered rock salt phase material can maintain the high configurational entropy of the high-entropy material while also having a higher specific capacity.
[0021] The local structure of the cathode material can be controlled by controlling the heating parameters. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Various other advantages and benefits of the present invention will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are intended only to illustrate preferred embodiments and are not to be construed as limiting the present invention. It should be understood that the drawings described below are merely examples of the present invention, and that those skilled in the art will be able to derive other drawings from these drawings without inventive effort. Throughout the drawings, identical reference numerals are used to denote identical components.
[0023] In the attached figure:
[0024] Figure 1 This is the XRD spectrum of the high-entropy cationic disordered rock salt phase cathode material prepared by this method. It can be seen that a pure phase can be obtained starting from 3 minutes;
[0025] Figure 2 This is the electron diffraction spectrum of the high-entropy cationic disordered rock salt phase cathode material prepared by this method. The diffraction pattern shows the existence of a local short-range ordered structure, which proves the feasibility of controlling the local structure in high-entropy materials.
[0026] Figure 3 Schematic diagram of the charge-discharge curves of the high-entropy cation disordered rock salt phase cathode material prepared by this method. The capacity was improved by more than 100 mAh / g, which is comparable to the result of ~250 mAh / g in the existing technology (Lun Z, OuyangB, Kwon DH, Ha Y, Foley EE, Huang TY, et al. Cation-disordered rocksalt-type high-entropy cathodes for Li-ion batteries. Nat Mater. 2021;20(2):214-222).
[0027] The present invention will be further explained below with reference to the accompanying drawings and embodiments. DETAILED DESCRIPTION
[0028] Specific embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although specific embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.
[0029] It should be noted that certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that technicians may use different nouns to refer to the same component. This specification and claims do not use the difference in nouns as a way to distinguish components, but use the difference in the functions of the components as the criterion for distinction. As mentioned throughout the specification and claims, "including" or "comprising" is an open term, so it should be interpreted as "including but not limited to". The subsequent description of the specification is a preferred embodiment of the present invention, but the description is based on the general principles of the specification and is not intended to limit the scope of the invention. The scope of protection of the present invention shall be as defined in the attached claims.
[0030] To facilitate understanding of the embodiments of the present invention, further explanation will be given below using specific embodiments as examples in conjunction with the accompanying drawings, and the accompanying drawings do not constitute a limitation on the embodiments of the present invention.
[0031] like Figures 1 to 3 As shown, the method for solid-phase synthesis of oxide positive electrode materials based on electron beam heating includes the following steps:
[0032] Step 1: The precursor powder of the positive electrode material is mixed uniformly to form a green body;
[0033] Step 2: Wrap the green body in graphite paper to form a sample, and place it on a sample stage;
[0034] Step 3, turn on the electron beam, use the electron beam to scan the sample for heating, wherein the heating rate and temperature are controlled by the voltage, current, scanning time interval and scanning rate of the electron beam; the voltage range of the electron beam is 10-100 keV, the upper limit is 100 keV, the lower limit is 10 keV, and the middle value is 60 keV; the current size is 5-100 mA, the upper limit is 100 mA, the lower limit is 5 mA, and the middle value is 40 mA; the scanning time interval is 5-20 seconds, the upper limit is 20 seconds, the lower limit is 5 seconds, and the middle value is 10 seconds; the scanning rate is 9.6-17.6 mm / s, the upper limit is 17.6 mm / s, the lower limit is 9.6 mm / s, and the middle value is 13.6 mm / s. When the upper limit parameter is used, the fastest heating rate can be obtained, which is suitable for materials that require rapid heat treatment; when the lower limit parameter is used, the most precise temperature control can be obtained, which is suitable for temperature-sensitive materials; when the intermediate value parameter is used, both the heating rate and temperature control accuracy can be taken into account, which is suitable for the preparation of most positive electrode materials.
[0035] Step 4: Grind the heated sample into powder to obtain a positive electrode material.
[0036] In a preferred embodiment of the method for solid-phase synthesis of oxide positive electrode materials based on electron beam heating, in step 1, the precursor powders are mixed based on the stoichiometric ratio of the positive electrode material of the final product.
[0037] In a preferred embodiment of the method for solid-phase synthesis of oxide positive electrode materials based on electron beam heating, in step 1, the precursor powder includes lithium fluoride or lithium carbonate, and the amount of the precursor powder is additionally added by 5%-20%.
[0038] In a preferred embodiment of the electron beam heating-based solid-phase synthesis method for oxide cathode materials, the precursor powders are mixed by ball milling and then formed into green sheets using a tablet press. The green sheets have a thickness ranging from 500 microns to 2 millimeters. Using an upper limit of 2 millimeters increases single-shot yield, but may require increasing heating time to ensure sufficient internal reaction. Using a lower limit of 500 microns further shortens heating time, but reduces single-shot yield. Using an intermediate value of 1 millimeter achieves a balance between yield and heating time, making it suitable for the preparation of most cathode materials.
[0039] In a preferred embodiment of the method for solid-phase synthesis of oxide positive electrode materials based on electron beam heating, the graphite paper is replaced by graphite felt or a porous graphite layer.
[0040] In a preferred embodiment of the method for solid-phase synthesis of oxide positive electrode materials based on electron beam heating, the thickness of the graphite paper is 1 micron to 3 mm.
[0041] In a preferred embodiment of the method for solid-phase synthesis of oxide positive electrode materials based on electron beam heating, the electron beam is used as a heat source, and high-speed electrons are used to collide with atoms in the sample or graphite lattice, generating lattice vibration for heating.
[0042] In a preferred embodiment of the method for solid-phase synthesis of oxide positive electrode materials based on electron beam heating, the voltage of the electron beam is 10 to 100 keV, and the current is 5 to 100 mA.
[0043] A solid-phase synthesized oxide positive electrode material is prepared by the method described.
[0044] In a preferred embodiment of the solid phase synthesis oxide positive electrode material, the solid phase synthesis oxide positive electrode material includes a high entropy cation disordered salt rock positive electrode, a sodium superion conductor (NASICON) structure material, Li7La3Zr2O 12 Solid-state electrolytes, high-entropy ceramic materials.
[0045] In one embodiment, an electron beam is used to directly heat a medium such as graphite to transfer heat to the sample. The heat source is not limited to an electron beam, and other ionizing radiation such as an ion beam can also be used as a heat source.
[0046] In one embodiment, the method includes,
[0047] Step 1. Mix the precursor powders evenly to form a green body; Step 2. Wrap the green body in graphite paper and place it on the sample stage; Step 3. Turn on the electron beam and scan the sample with the electron beam according to the set program; Step 4. Grind the heated sample into powder. This can achieve rapid and efficient preparation of a large number of positive electrode materials, while retaining high structural entropy in the preparation of high entropy materials. For example, in high entropy cationic disordered rock salt phase materials (TM4, Li 1.3 Mn(II) 0.2 Mn(III) 0.2 Ti 0.1 Nb 0.2 O 1.7 F 0.3 ) was prepared in a time of less than a minute, and pure phase synthesis and high configurational entropy were obtained, especially with a significant improvement in specific capacity.
[0048] In one embodiment, the method includes,
[0049] Step 1. The precursor powders are mixed uniformly to form a green body. This method is characterized in that the precursor powders need to be mixed based on the stoichiometric ratio of the final product. When the powder contains raw materials that are easily lost by vaporization, the amount of raw materials needs to be increased as appropriate. For example, when the raw materials contain lithium sources such as lithium fluoride and lithium carbonate, an additional 5%-20% of the material needs to be added because they are easily lost by vaporization at high temperatures, resulting in loss of lithium and fluorine elements.
[0050] The precursors can be mixed using, but are not limited to, ball milling. A tablet press can be used to form a green body. The diameter of the green body is not limited. Depending on the number of samples required and the size of the sample stage, the thickness of the green body can range from 500 μm to 2 mm.
[0051] Step 2. Wrap the green body in graphite paper and place it on the sample stage. The graphite paper serves to reduce electron beam damage to the sample, acting as a buffer layer, generating some heat during electron beam bombardment, and reducing static electricity or charge accumulation. Graphite paper can be replaced with graphite felt or porous graphite sheets, with thicknesses ranging from 1 micron to 3 mm.
[0052] Step 3. Turn on the electron beam and scan the sample using the electron beam according to the programmed procedure. Using an electron beam as a heat source differs from other heating methods, such as Joule heating, flash heating, and laser heating, in that it utilizes high-speed electrons to impact atoms in the sample's crystal lattice, generating lattice vibrations and heating. Electron beam parameters can be set from a voltage of 10 to 100 keV and a current of 5 to 100 mA. The heating rate and temperature can be controlled by adjusting the voltage, current, scanning interval, and scanning rate.
[0053] Step 4. Grind the heated sample into powder.
[0054] This method is suitable for solid phase synthesis, not only for oxide cathode materials, but also for other materials that require solid phase synthesis methods, such as high entropy cation disordered salt rock cathode, NASICON, Li7La3Zr2O 12 , high entropy ceramics, etc. This method can prepare multiple samples at one time. Multiple samples can be laid out according to the size of the sample stage. Different experimental parameters can be selected for different samples for electron beam scanning heating.
[0055] Example
[0056] The precursors Li2CO3, MnO, Mn2O3, TiO2, Nb2O5, and LiF were prepared according to the 1.3 Mn(II) 0.2 Mn(III) 0.2 Ti 0.1 Nb 0.2 O 1.7 F 0.3 The stoichiometric ratio is adopted, and an additional 10% of Li2CO3 and LiF are added to compensate for the loss of Li and F during the heating process.
[0057] After the precursors are fully mixed using a ball mill, they are placed in a tablet press to prepare a series of green sheets with a diameter of 13 mm and a thickness of about 1 mm.
[0058] The green embryo was wrapped with graphite paper and fixed to the sample stage. The electron beam current was set at 40 mA, the optimal beam defocus value was fixed at 0.2, and the scan rate was fixed at 13.6 mm / s. The chamber door was then closed and evacuated. After this, nitrogen was filled in. After the chamber pressure was adjusted to the appropriate level, the beam was removed. Following electron beam irradiation, the cathode material was thermally synthesized. After the set time of 1 minute, 3 minutes, or 5 minutes, the electron beam was turned off and the sample was removed.
[0059] The sintered positive electrode material sheet is ground to obtain positive electrode powder, which is then subjected to XRD and transmission electron diffraction analysis.
[0060] The positive electrode powder was prepared into positive electrode sheets for battery testing.
[0061] From the XRD spectrum ( Figure 1 ) can be seen from the graph that as the time increases to 3 min, the phase of the obtained positive electrode material changes to a pure phase, and from the transmission electron diffraction spectrum ( Figure 2 ), which proves the existence of short-range order in the sample and proves that this method has potential application in controlling local structure. Figure 3 The charge-discharge curves prove that the cathode material prepared by this method has an outstanding specific capacity, which is 100 mAh / g higher than that of the existing technology.
[0062] Although the embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to the above-mentioned specific embodiments and application fields. The above-mentioned specific embodiments are merely illustrative and instructive, and are not restrictive. A person skilled in the art, guided by this specification and without departing from the scope of protection of the claims of the present invention, may also devise various forms, all of which fall within the scope of protection of the present invention.
Claims
1. A method for solid-phase synthesis of oxide positive electrode materials based on electron beam heating, characterized in that: The steps include: Step 1: The precursor powder of the positive electrode material is mixed uniformly to form a green body; Step 2: Wrap the green body in graphite paper to form a sample, and place it on a sample stage; Step 3: Turn on the electron beam and use it to scan the sample for heating. The heating rate and temperature are controlled by the voltage, current, scanning time interval, and scanning rate of the electron beam: Step 4: Grind the heated sample into powder to obtain a positive electrode material.
2. The method for solid-phase synthesis of oxide positive electrode materials based on electron beam heating according to claim 1, characterized in that: Preferably, in step 1, the precursor powders are mixed based on the stoichiometric ratio of the cathode material of the final product.
3. The method for solid-phase synthesis of oxide positive electrode materials based on electron beam heating according to claim 2, characterized in that: In step 1, the precursor powder includes lithium fluoride or lithium carbonate, and the amount of the precursor powder is additionally added by 5%-20%.
4. The method for solid-phase synthesis of oxide positive electrode materials based on electron beam heating according to claim 1, characterized in that: The precursor powders are mixed by a sampling ball mill and a tablet press is used to form a green embryo, the thickness of which is between 500 microns and 2 mm.
5. The method for solid-phase synthesis of oxide positive electrode materials based on electron beam heating according to claim 1, characterized in that: The graphite paper is replaced by graphite felt or porous graphite layer.
6. The method for solid-phase synthesis of oxide positive electrode materials based on electron beam heating according to claim 1, characterized in that: Graphite paper thickness ranges from 1 micron to 3 mm.
7. The method for solid-phase synthesis of oxide positive electrode materials based on electron beam heating according to claim 1, characterized in that: The electron beam is used as a heat source, using high-speed electrons to collide with atoms in the sample / heat transfer medium lattice, generating lattice vibrations for heating and achieving heat input.
8. The method for solid-phase synthesis of oxide positive electrode materials based on electron beam heating according to claim 1, characterized in that: The electron beam voltage is 10 to 100 keV and the current is 5 to 100 mA.
9. A solid phase synthesized oxide positive electrode material, characterized in that It is prepared by the method according to any one of claims 1 to 8.
10. The solid phase synthesized oxide positive electrode material according to claim 9, characterized in that: Solid-phase synthesis of oxide cathode materials includes high entropy cation disordered salt rock cathode, sodium superion conductor (NASICON) structural materials, Li7La3Zr2O 12 Solid-state electrolytes, high-entropy ceramic materials.