Spherical-like composite phase high-entropy layered metal oxide and preparation method and application thereof
By preparing spherical composite phase high-entropy layered metal oxides through mixing granulation and microwave heating, the problems of insufficient stability and density of existing sodium-ion battery cathode materials are solved, and high-performance sodium-ion battery cathode materials are prepared.
Patent Information
- Application Number
- CN202511049722.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-29
- Publication Date
- 2025-11-04
AI Technical Summary
Existing high-entropy layered oxide cathode materials suffer from poor cycle stability, easy deactivation upon reaction with air, and insufficient tap density in sodium-ion batteries. Furthermore, the synthesis methods result in irregular sheet-like structures with poor performance.
A near-spherical composite phase high-entropy layered metal oxide was prepared using a hybrid granulation technique and a microwave heating method. By controlling the microwave heating time and temperature, a stable near-spherical structure was formed. Combined with suitable sintering conditions, uniform mixing and particle bonding of the material were achieved.
This improved the cycle stability, air stability, and tap density of the sodium-ion battery cathode material, enhanced its electrochemical performance, and met the needs of industrial production.
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Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of electrochemical cells, and more particularly relates to a kind of spherical composite phase high-entropy layered metal oxide and its preparation method and application. BACKGROUND
[0002] Lithium-ion batteries have been widely used in various power storage and use scenarios due to their high energy density, simple synthesis method, and long cycle life, but the cost of the batteries is relatively high. Therefore, sodium-ion batteries with abundant reserves and low cost have become a supplement and replacement for lithium-ion batteries. Since the cathode material is the key to determining the energy density and cost of sodium-ion batteries, it is necessary to develop new cathode materials. Currently, the main sodium-ion battery cathode materials include layered transition metal oxides, polyanion compounds, and Prussian blue and its analogues. Existing layered oxide cathode materials are mainly divided into two categories: "P" type and "O" type. The "O" type cathode material has a high discharge specific capacity, but its cycle stability is poor. The "P" type cathode material has good cycle stability, but its discharge specific capacity is relatively low. Therefore, it is of great significance to develop a new sodium-ion battery cathode material that combines the advantages of "P" type and "O" type materials.
[0003] High-entropy materials are a new type of material with high mixing entropy, composed of five or more elements, which usually exhibit excellent performance. Due to the diversity of elements in this high-entropy material, the entropy of the host lattice is more stable. The introduction of high-entropy configuration in sodium-ion battery layered oxide cathode materials can effectively inhibit the phase transition during the intercalation / deintercalation process of sodium ions, resulting in better cycle life and rate performance of the material. In current related research, the synthesis method of high-entropy layered oxides is mainly ball milling. The high-entropy layered oxides synthesized by ball milling have irregular flaky structures, and the cycle rate performance of the material is poor. Moreover, harmful side reactions occur between the material and water and carbon dioxide in the air after contact, leading to the denaturation and inactivation of the material. In addition, the tap density of the cathode material needs to be further improved to meet the needs of industrial production and application.
[0004] Therefore, the present application is proposed. SUMMARY
[0005] The purpose of the present application is to provide a kind of spherical composite phase high-entropy layered metal oxide and its preparation method and application, to solve the problems existing in the prior art, and to realize the preparation of "P" type and "O" type sodium-ion battery cathode materials.
[0006] To achieve the above-mentioned purpose, the present application provides the following solutions:
[0007] One of the technical solutions of the present application: a preparation method of a quasi-spherical composite phase high-entropy layered metal oxide, comprising the following steps:
[0008] According to the molecular formula Na a Ge b Cu c Ce d Ti e Te f O2, wherein 0.6≤a≤1, 0 The sodium source, germanium source, copper source, cerium source, titanium source and tellurium source are weighed; the germanium source, copper source, cerium source, titanium source and tellurium source are mixed and granulated, and a precursor is prepared by microwave heating; the sodium source is added to the precursor and mixed, and the quasi-spherical composite phase high-entropy layered metal oxide is obtained by sintering.
[0009] Further, the value of b is further preferably 0.1≤b≤0.2.
[0010] Preferably, the sodium source includes at least one of sodium carbonate, sodium acetate, sodium nitrate and sodium hydroxide; the germanium source includes germanium oxide and / or germanium dioxide; the copper source includes at least one of copper oxide, copper sulfate and copper nitrate; the cerium source includes at least one of cerium dioxide, cerium sulfate and cerium nitrate; the titanium source includes titanium dioxide and / or titanium tetrachloride; and the tellurium source is tellurium trioxide and / or tellurium dioxide.
[0011] Preferably, the temperature of the mixed granulation is 50-100℃; and the primary particle size of the mixture obtained after the mixed granulation is 200-300nm.
[0012] The raw materials are fully mixed and uniform by the mixed granulation technology, compared with the conventional mixing process, the mixed granulator used in the present application not only can fully mix and uniform the raw materials, but also has the function of granulation, so that the primary particles are assembled into secondary particles with quasi-spherical precursor.
[0013] Preferably, the temperature of the microwave heating is 100-300℃, and the time is 5-30min.
[0014] Further, the temperature of the microwave heating is further preferably 120-250℃, and the time is further preferably 10-25min.
[0015] Preferably, the sintering temperature is 900-1100 DEG C, and the time is 6-10 h. By adjusting the microwave heating time and temperature, the present application can realize the size control of the primary nanoparticles and the secondary spherical particles, ensure the structure of the prepared spherical composite phase high-entropy layered metal oxide to be more stable, effectively improve the tap density, and effectively improve the cycle stability and air stability of the sodium ion battery cathode material. The reason is that the microwave heating energy is high, the drying speed of the equipment is fast, the material is heated from the inside to the outside at the same time, and the temperature difference between the inside and the outside of the material is small, and the heating is uniform. Such characteristics enable the mixed granulated precursor to be stably connected between the primary particles after microwave heating, thereby laying a good foundation for the subsequent sintering to form a structure-stable spherical metal oxide. The present application controls the microwave heating temperature to be 100-300 DEG C, and the time is 5-30 min. In this range, the morphology and structure stability of the sodium ion battery cathode material can be effectively ensured; when the temperature exceeds 300 DEG C, the primary particles of the precursor increase, and dense spherical secondary particles are formed. After calcination in a muffle furnace, the cathode material is difficult to be impregnated with electrolyte, which is not conducive to the performance of the electric performance. When the temperature is lower than 100 DEG C, the contact between the primary particles of the precursor is unstable and not firm, and the particles are easy to be loose. After calcination in a muffle furnace, it is difficult to form spherical secondary particles; when the time exceeds 30 min, the spherical precursor secondary particles are too dense, and when the time is less than 5 min, the primary particles of the precursor are loose.
[0016] Suitable sintering temperature and time are beneficial to the phase formation and particle growth of the sodium ion cathode material. If the sintering temperature is too high and the time is too long, the crystal grains further grow, the particles are too large, and the sodium ion transmission is affected. If the sintering temperature is too low and the time is too short, the crystallinity of the cathode material and the formation of the layered oxide phase are affected.
[0017] By the mixing granulation technology and the adjustment of the microwave heating parameters, the present application significantly reduces the size of the obtained material and the diffusion path of sodium ions, and effectively improves the performance, structural stability and tap density of the obtained material.
[0018] The second technical scheme of the present application provides the spherical composite phase high-entropy layered metal oxide prepared by the above preparation method.
[0019] The third technical scheme of the present application provides the application of the above spherical composite phase high-entropy layered metal oxide in the preparation of a sodium ion battery.
[0020] The present application discloses the following technical effects:
[0021] The application obtains the spherical material by mixing and granulating sodium raw materials, and then synthesizing and calcining by microwave, wherein the crystal structure of the spherical material is P2+O3 phase layer structure, the composite phase metal oxide has the advantages of P-type and O-type sodium ion battery positive electrode materials, and shows good discharge specific capacity and cycle stability. The preparation method provided by the application has good crystallinity and uniform particle size of the metal oxide, and has low equipment requirement, simple operation, low cost, strong controllability, high purity of the synthesized sample, good repeatability, good adaptability, and meets the requirements of industrial production.
[0022] The application fully mixes the raw materials by using the mixing and granulating technology, and realizes the size controllability of the primary nanoparticles and the secondary spherical particles by adjusting the microwave heating time and temperature. The spherical composite phase high-entropy layer metal oxide obtained has more stable structure, and the tap density is effectively improved, thereby effectively improving the cycle stability and air stability of the sodium ion battery positive electrode material. Moreover, the preparation method of the application is environment-friendly, pollution-free, and low in process cost. BRIEF DESCRIPTION OF DRAWINGS
[0023] Figure 1 A scanning electron microscope image of the sodium ion battery positive electrode material prepared in Example 2;
[0024] Figure 2 A transmission electron microscope image of the sodium ion battery positive electrode material prepared in Example 2;
[0025] Figure 3 A scanning electron microscope image of the sodium ion battery positive electrode material prepared in Comparative Example 9;
[0026] Figure 4 A transmission electron microscope image of the sodium ion battery positive electrode material prepared in Comparative Example 9. DETAILED DESCRIPTION
[0027] The various illustrative embodiments of the application will now be described in detail in connection with the accompanying drawings, which are illustrated for the purpose of exemplification only and are not intended to limit the application. It should be understood that they have been presented by way of example only, and are not intended to limit the scope of the application in any manner. Descriptions and principles of various steps and embodiments are applicable to other example embodiments as complementary descriptions.
[0028] It should be understood that the terms used in the present application merely describe particular embodiments and are not intended to limit the present application. In addition, for the numerical ranges in the present application, it should be understood that each intermediate value between the upper limit and the lower limit of the range is also specifically disclosed. Each smaller range within any stated range or within any stated intermediate value, as well as any other stated value or intermediate value within the stated range, is also included in the present application. The upper limit and the lower limit of these smaller ranges can be included or excluded independently from the range.
[0029] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as those commonly understood by one of ordinary skill in the art to which this application pertains. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application, the preferred methods and materials are described. All publications mentioned in this specification are herein incorporated by reference to disclose and describe the methods and / or materials in connection with which the publications are cited. The citation of any reference is not an admission that it is prior art with respect to the present application.
[0030] Many modifications and variations of the present application described in the specification are possible without departing from the scope or spirit of the application. Other implementations of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. The specification and examples given are exemplary only.
[0031] It is to be understood that the singular forms "a", "an", and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a component" includes reference to one or more components.
[0032] It should be noted that the present application does not describe in detail the conventional means in the art, and is not the focus of the present application.
[0033] The raw materials used in the following examples and comparative examples of the present application are commercially available unless otherwise specified, and the source of the commercially available products does not affect the technical effects of the present application.
[0034] Example 1
[0035] Na 0.6 Ge 0.1 Cu 0.1 Ce 0.3 Ti 0.3 Te 0.1 O2stoichiometric ratio of germanium dioxide, copper oxide, cerium sulfate, titanium tetrachloride, and tellurium dioxide were weighed and mixed in a mixing granulator at a speed of 150 r / min and a heating temperature of 100°C. The particle size of the mixed material obtained after mixing granulation was 200-300 nm. The granulated mixture was treated in a microwave synthesis system at 250°C for 10 min to prepare a precursor. The precursor was mixed with sodium carbonate and heated to 900°C for 10 h. After the furnace was cooled to room temperature, it was transferred to a glove box to obtain a spherical composite phase high-entropy layered metal oxide, which is a sodium ion battery cathode material.
[0036] Battery preparation and testing: 0.14 g of the prepared sodium-ion battery anode material was weighed, 0.04 g of acetylene black and 0.02 g of PVDF dissolved in N,N-dimethylpyrrolidone were added, and polyvinylidene fluoride (PVDF) was used as a binder, mixed uniformly to form a slurry, uniformly coated on an aluminum foil, and assembled into a CR2032 type button cell in an argon atmosphere glove box with a metal sodium sheet as the counter electrode, glass fiber as the separator, and 1 mol / L NaClO4(PC:FEC = 1:1) as the electrolyte. The test instrument was a LAND CT2001 type battery test system. The battery was subjected to charge-discharge cycle test at 25℃, 2.0-4.3V voltage range, 0.5C rate, and the cycle number was 300 times. The initial discharge specific capacity and the discharge specific capacity after 300 cycles were recorded, and the results are shown in Table 1.
[0037] Example 2
[0038] NaGe 0.15 Cu 0.2 Ce 0.2 Ti 0.2 Te 0.1 O2 Stoichiometric ratio of germanium dioxide, copper nitrate, cerium nitrate, titanium dioxide, and tellurium dioxide was mixed and granulated in a mixing granulator at a speed of 200 r / min and a heating temperature of 80℃. The particle size of the mixed material obtained after mixing and granulating was 200-300 nm. The granulated mixture was treated in a microwave synthesis system at 200℃ for 15 min to prepare a precursor; the precursor was mixed with sodium carbonate and heated to 950℃ for 9 h, and then transferred to a glove box after the furnace was cooled to room temperature to obtain a spherical composite phase high-entropy layered metal oxide, which is a sodium-ion battery anode material. The scanning electron microscope image of the obtained sodium-ion battery anode material is shown in Figure 1 , and the transmission electron microscope image is shown in Figure 2 .
[0039] Battery preparation and testing method same as example 1.
[0040] Example 3
[0041] Na 0.9 Ge 0.2 Cu 0.15 Ce 0.3 Ti 0.25 Te 0.05O2stoichiometrically weighed germanium dioxide, copper sulfate, cerium sulfate, titanium dioxide, and tellurium dioxide in a mixing granulator, the rotation speed was 250 r / min, the heating temperature was 50 °C, the primary particle size of the obtained mixture after mixing granulation was 200-300 nm. The granulated mixture was treated in a microwave synthesis system at 180 °C for 20 min to prepare a precursor; the precursor was mixed with sodium hydroxide and heated to 1030 °C for 7 h, and then transferred to a glove box after the furnace was cooled to room temperature to obtain a spherical composite phase high-entropy layered metal oxide, which is a sodium ion battery cathode material.
[0042] The battery manufacturing and testing method is the same as that of Example 1.
[0043] Example 4
[0044] According to Na 0.7 Ge 0.12 Cu 0.11 Ce 0.1 Ti 0.4 Te 0.1 O2stoichiometrically weighed germanium dioxide, copper sulfate, cerium sulfate, titanium dioxide, and tellurium dioxide in a mixing granulator, the rotation speed was 250 r / min, the heating temperature was 50 °C, the primary particle size of the obtained mixture after mixing granulation was 200-300 nm. The granulated mixture was treated in a microwave synthesis system at 180 °C for 20 min to prepare a precursor; the precursor was mixed with sodium hydroxide and heated to 1030 °C for 7 h, and then transferred to a glove box after the furnace was cooled to room temperature to obtain a spherical composite phase high-entropy layered metal oxide, which is a sodium ion battery cathode material.
[0045] The battery manufacturing and testing method is the same as that of Example 1.
[0046] Example 5
[0047] According to Na 0.9 Ge 0.15 Cu 0.05 Ce 0.4 Ti 0.15 Te 0.05 O2stoichiometrically weighed germanium dioxide, copper sulfate, cerium sulfate, titanium dioxide, and tellurium dioxide in a mixing granulator, the rotation speed was 250 r / min, the heating temperature was 50 °C, the primary particle size of the obtained mixture after mixing granulation was 200-300 nm. The granulated mixture was treated in a microwave synthesis system at 180 °C for 20 min to prepare a precursor; the precursor was mixed with sodium hydroxide and heated to 1030 °C for 7 h, and then transferred to a glove box after the furnace was cooled to room temperature to obtain a spherical composite phase high-entropy layered metal oxide, which is a sodium ion battery cathode material.
[0048] The battery manufacturing and testing methods are the same as in Example 1.
[0049] Comparative Example 1
[0050] Same as Example 1, except that ball milling is used to mix the raw materials. Specifically, the same raw materials are added to the ball mill jar with a ball-to-material ratio of 3:1 and a rotation speed of 250 r / min.
[0051] Comparative Example 2
[0052] Same as Example 2, except that the raw materials are mixed by sand milling. Specifically, the same raw materials are added to a sand mill, 300 mL of deionized water is added, and the speed is 250 r / min.
[0053] Comparative Example 3
[0054] Similar to Example 3, except that the raw materials are mixed by ball milling, and the microwave heating treatment is changed to be processed in a conventional forced-air drying oven. Specifically, the same raw materials are added to the ball mill jar with a ball-to-material ratio of 3:1 and a rotation speed of 250 r / min. The ball-milled mixture is dried at 180°C for 20 min in a forced-air drying system to obtain the precursor.
[0055] Comparative Example 4
[0056] Similar to Example 4, except that the raw materials are mixed by ball milling, and the microwave heating treatment is changed to treatment in a vacuum drying oven. Specifically, the same raw materials are added to a ball mill jar with a ball-to-material ratio of 3:1 and a rotation speed of 250 r / min. The ball-milled mixture is then treated in a vacuum air drying system at 150°C for 22 min to prepare the precursor.
[0057] Comparative Example 5
[0058] Same as Example 5, except that the microwave heating temperature is adjusted to 400°C.
[0059] Comparative Example 6
[0060] Same as Example 5, except that the microwave heating temperature is adjusted to 80°C.
[0061] Comparative Example 7
[0062] Same as Example 5, except that the microwave heating time is adjusted to 35 minutes.
[0063] Comparative Example 8
[0064] Same as Example 5, except that the microwave heating time is adjusted to 3 minutes.
[0065] Comparative Example 9
[0066] The same as Example 2, except that the raw materials were weighed according to NaGe 0.21 Cu 0.06 Ce 0.2 Ti 0.3 Te 0.1 The raw materials were weighed according to the stoichiometric ratio of O2. Figure 3 The scanning electron microscope image of the sodium ion battery cathode material prepared by this method is shown in Figure 4 .
[0067] Comparative Example 10
[0068] The same as Example 2, except that the raw materials were weighed according to NaGe 0.09 Cu 0.12 Ce 0.2 Ti 0.3 Te 0.1 The raw materials were weighed according to the stoichiometric ratio of O2.
[0069] The scanning electron microscope and transmission electron microscope were used to observe the sodium ion battery cathode materials prepared in Example 2 and Comparative Example 9, as shown in Figure 1 , Figure 2 , Figure 3 , Figure 4 .
[0070] Figure 1 The scanning electron microscope image of the sodium ion battery cathode material prepared in Example 2;
[0071] Figure 2 The transmission electron microscope image of the sodium ion battery cathode material prepared in Example 2;
[0072] Figure 3 The scanning electron microscope image of the sodium ion battery cathode material prepared in Comparative Example 9;
[0073] Figure 4 The transmission electron microscope image of the sodium ion battery cathode material prepared in Comparative Example 9.
[0074] The test results of the electrical performance of the batteries assembled with the sodium ion battery cathode materials obtained in Examples 1-5 and Comparative Examples 1-10 are shown in Table 1.
[0075] Table 1 Electrical performance of sodium ion battery cathode materials
[0076]
[0077]
[0078] The tap density and discharge specific capacity after exposure to a 60% humidity open-air environment for 10 days of the sodium ion battery cathode materials obtained in Examples 1-5 and Comparative Examples 1-10 were detected, and the results are shown in Table 2.
[0079] Table 2 tap density and discharge specific capacity after 10d exposure of sodium ion battery cathode materials
[0080]
[0081] From Figure 1 , Figure 2 , Figure 3 , Figure 4 It can be seen that the sodium ion battery cathode material synthesized by using the mixed granulation technology has a spherical structure, and the sodium ion battery high-entropy cathode material prepared by using the ball milling method is a flaky structure. From Figures 1 to 4 and Tables 1-2, it can be concluded that the sodium ion battery cathode material with a spherical structure prepared by using the mixed granulation technology can effectively improve the specific capacity and cycle stability of the sodium ion battery, and the high tap density of the cathode material lays a foundation for realizing high energy density of the sodium ion battery, and the spherical cathode material has excellent air stability.
[0082] Each embodiment in the specification is described in a progressive manner, and each embodiment focuses on the difference from other embodiments, and the same or similar parts between each embodiment can be referred to each other.
[0083] The above description of the disclosed embodiments enables a person skilled in the art to implement or use the present application. Various modifications to the embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A method for preparing a spherical composite phase high-entropy layered metal oxide, characterized in that, Includes the following steps: According to the molecular formula Na a Ge b Cu c Ce d Ti e Te f O2, where 0.6≤a≤1, 0<b≤0.2, 0<c≤0.2, 0<d≤0.4, 0<e≤0.4, 0<f≤0.1, 1.5≤a+b+c+d+e+f≤1.85, sodium source, germanium source, copper source, cerium source, titanium source and tellurium source are weighed; the germanium source, copper source, cerium source, titanium source and tellurium source are mixed and granulated, and a precursor is prepared by microwave heating; sodium source is added to the precursor and mixed, and sintered to obtain the spherical composite phase high-entropy layered metal oxide.
2. The preparation method according to claim 1, characterized in that, The sodium source includes at least one of sodium carbonate, sodium acetate, sodium nitrate, and sodium hydroxide; the germanium source includes germanium oxide and / or germanium dioxide; the copper source includes at least one of copper oxide, copper sulfate, and copper nitrate; the cerium source includes at least one of cerium dioxide, cerium sulfate, and cerium nitrate; the titanium source includes titanium dioxide and / or titanium tetrachloride; and the tellurium source is tellurium trioxide and / or tellurium dioxide.
3. The preparation method according to claim 1, characterized in that, The mixing and granulation temperature is 50–100°C; the primary particle size of the mixture obtained after mixing and granulation is 200–300 nm.
4. The preparation method according to claim 1, characterized in that, The microwave heating temperature is 100–300°C, and the time is 5–30 minutes.
5. The preparation method according to claim 1, characterized in that, The sintering temperature is 900–1100℃, and the time is 6–10 hours.
6. The near-spherical composite phase high-entropy layered metal oxide prepared by the preparation method according to any one of claims 1 to 5.
7. The application of the near-spherical composite phase high-entropy layered metal oxide as described in claim 6 in the preparation of sodium-ion batteries.