A microcrystalline glass / porous fiber anode material and its preparation method

Abstract

This invention discloses a microcrystalline glass / porous fiber anode material and its preparation method, belonging to the field of battery anode materials. The microcrystalline glass is characterized by being a fluorine-oxygen metal oxide co-doped microcrystalline glass, wherein the fluorine-oxygen metal oxide is two or more of stannous fluoride, stannous oxide, germanium oxide, and selenium oxide. The fluorine-oxygen metal oxide co-doped microcrystalline glass anode material is a microcrystalline glass material with a stable perovskite structure within an amorphous network structure. It is obtained by high-temperature melting-cold extraction-melting-cold extraction followed by grinding into powder. The porous fiber is bamboo carbon fiber with mesopore size. The powder is embedded into the bamboo material using a negative pressure adsorption method and then carbonized to finally obtain the microcrystalline glass / porous fiber anode material. This method has a simple manufacturing process, excellent electrochemical performance, and can be used in the battery industry.

Description

Technical Field

[0001] This invention patent relates to an electrode material, specifically to a microcrystalline glass / porous fiber anode material and its preparation method. Background Technology

[0002] Lithium-ion batteries are currently the fastest-growing energy storage devices, widely used in portable power sources such as mobile phones, laptops, and electric vehicles. The performance of lithium-ion batteries primarily depends on the performance of the lithium-ion electrode materials used for lithium intercalation and deintercalation. Currently, commercially available graphite anode materials for lithium-ion batteries suffer from low theoretical lithium storage capacity and are prone to organic solvent co-intercalation, severely hindering the practical application of lithium-ion batteries. Finding anode materials with high specific capacity and high cycle performance is a key problem that researchers and companies are striving to solve.

[0003] In oxide-containing glass-ceramics, the stronger the bond strength of the oxide, the more robust the anion clusters after melting. Therefore, bond breakage and recombination are more difficult, resulting in higher nucleation barriers and hindering crystallization. The stability of perovskite materials can also be improved by doping elements at the interfaces or grain boundaries of quantum dot-rich glass-ceramics. Therefore, the choice of substitution or doping elements has a significant impact on the stability of perovskite materials. For example, the introduction of fluoride ions can promote ion diffusion within the glass-ceramic, reducing crystallization. Specifically, when fluoride ions begin to enter the glass structure and replace non-bridging oxygen ions, the glass network structure is weakened, and the glass viscosity decreases. When the glass viscosity decreases, the nucleation and crystal growth rates can be increased. Furthermore, in Cs₄PbBr₆, due to Sn… 5n Lone electrons compared to Pb 6s The lone pairs of electrons are more active, resulting in a lower formation enthalpy for the main tin vacancy defects. This makes the Cs4PbBr6 structure more stable. Therefore, replacing Pb ion sites with Sn ions to improve the stability of Cs4PbBr6 quantum dot glass-ceramic materials (GCs) is a viable approach.

[0004] Existing technology, such as patent application number CN 110335987 A, discloses a method for preparing TeO2-MoO3-Fe2O3 microcrystalline glass that can be used as a negative electrode material for lithium-ion batteries. This invention relates to the field of lithium-ion battery electrode material design and research on the lithium storage performance of oxide glasses. In this invention, oxides of tellurium, molybdenum, and iron are weighed according to a specific ratio, ground, and poured into an alumina crucible. This crucible is then placed in a high-temperature resistance furnace and heated until it melts. The molten material is then rapidly poured out and cooled to obtain a blocky microcrystalline glass. The particle size and amount of crystals precipitated in the microcrystalline glass can be controlled by adjusting the amount of tellurium, molybdenum, and iron added. The blocky microcrystalline glass is then crushed, ground, and mixed with a conductive agent and binder in a mass ratio, and a solvent is added for ball milling. The resulting slurry is coated onto copper foil to obtain a lithium-ion battery negative electrode material. However, this secondary battery negative electrode material has a simple structure, which is not conducive to improving the specific capacity of lithium-ion batteries and significantly reduces reaction efficiency. Summary of the Invention

[0005] This invention addresses the problems of large volume changes and short cycle life of metal oxide anode materials during storage in the prior art, and provides a microcrystalline glass / porous fiber anode material with long life and large specific capacity, as well as a preparation method thereof.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A microcrystalline glass / porous fiber anode material is characterized in that the microcrystalline glass is a fluorine-oxygen metal oxide co-doped microcrystalline glass, wherein the fluorine-oxygen metal oxide is two or more of stannous fluoride, stannous oxide, germanium oxide, and selenium oxide; the fluorine-oxygen metal oxide co-doped glass anode material is a microcrystalline glass material with a stable perovskite structure in an amorphous network structure, which is obtained by high-temperature melting-cold extraction-melting-cold extraction followed by grinding into powder; the porous fiber is bamboo carbon fiber with mesopore size, which is embedded into the bamboo material by negative pressure adsorption and then carbonized to finally obtain the microcrystalline glass / porous fiber anode material.

[0008] Preferably, the mass composition ratio of GeO2:H3BO3:PbO:CsCO3:PbBr2:NaBr:fluoride:oxide is (2-12):(3-5):(0.2-1.3):(0.3-0.7):(0.6-0.75):(0.5-0.8):(0.8-0.93):(0.8-0.93).

[0009] Preferably, the perovskite structure is cesium bromide-lead-cesium-based perovskite, and a cubic CsPF6 structure is generated during the charge and discharge process.

[0010] This invention also includes a method for preparing a microcrystalline glass / porous fiber anode material, comprising:

[0011] 1) Weigh the powder with the mass ratio of GeO2:H3BO3:PbO:CsCO3:PbBr2:NaBr:fluoride:oxide in (2~12):(3~5):(0.2~1.3):(0.3~0.7):(0.6~0.75):(0.5~0.8)(0.8~0.93):(0.8~0.93) as the starting material. After thorough mixing, place the batch into an alumina crucible and melt it in an electric furnace at 780℃ for 30 minutes. Then remove it and cold extract it, followed by annealing at 300℃. Then place it in a glass melting furnace for remelting at 1200℃ for 2 hours. After 2 hours, reduce the temperature to 200℃ and hold it at that temperature for 0.5 hours under helium atmosphere protection.

[0012] 2) Take porous bamboo and soak it in the prepared mixed alkali treatment solution, then rinse it with deionized water and set aside; (to remove nutrients from the bamboo, such as sugar and starch) the wood pores will become larger;

[0013] 3) Soak the alkaline-pretreated bamboo in MA (maleic anhydride) dissolved in toluene for 3-6 hours; then soak it in a vacuum impregnation (>0.1MPa) solution containing a reinforcing anti-rebound resin solution for a period of time (>1 hour), remove it, remove the surface resin and set aside for use.

[0014] 4) Place the product from step 1) above the product from step 3), and place the bamboo containing fluorine oxide metal oxide co-doped glass powder above the negative pressure machine and adjust the air pressure to -100Mpa for 30 minutes.

[0015] 5) After mixing the products from step 4), place them in a freeze dryer and pre-freeze them to -60°C. Then, dry them under vacuum. After drying, place them in a helium tube furnace for carbonization to obtain the final product, microcrystalline glass / porous fiber anode material.

[0016] Preferably, in step 2), the alkaline solution is 2.5 mol / L sodium hydroxide and 0.4 mol / L sodium sulfite, and the treatment time is 6 hours at 80°C.

[0017] Compared with existing technologies, a microcrystalline glass / porous fiber anode material and its preparation method have the following advantages:

[0018] 1) In the microcrystalline glass / porous fiber anode material prepared by the present invention, the glass is microcrystalline glass, which has a rich amorphous network structure with many active sites, thus improving the loading efficiency of the active material.

[0019] 2) In the microcrystalline glass / porous fiber negative electrode material prepared by the present invention, the porous fiber substrate is bamboo with rich pore structure, which can better adsorb powder. After carbonization, porous fibers are obtained, which have higher conductivity.

[0020] 3) The microcrystalline glass / porous fiber anode material prepared by this invention generates a cubic CsPF structure during charge and discharge. 6， The cubic structure of CsPF6 can further extend the cycle life of glass-ceramic / porous fiber anode materials, reaching up to 1500 cycles. Attached Figure Description

[0021] Figure 1 Scanning electron microscope image of glass-ceramic / porous fiber anode material

[0022] Figure 2 Scanning electron microscope image after charge-discharge cycle in Example 3 Detailed Implementation

[0023] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that several improvements and extensions can be made without departing from the concept of the present invention, and these should all fall within the protection scope of the present invention.

[0024] Example 1

[0025] Preparation of a microcrystalline glass / porous fiber anode material

[0026] 1) Using GeO2-B2O3-PbO-Cs2CO3-PbBr-NaBr-SnF2-SeO powder in a mass ratio of 2:5:0.2:0.7:0.75:0.8:0.93:0.93 as the starting material, after thorough mixing, the batch was placed in an alumina crucible and melted in an electric furnace at 780℃ for 30 minutes. It was then removed, cold-extracted, and annealed at 300℃. It was then placed in a glass melting furnace for remelting at 1200℃ for 2 hours. After 2 hours, the temperature was lowered to 200℃ and held constant for 0.5 hours under a helium atmosphere.

[0027] 2) Take porous bamboo and soak it in a mixed alkaline treatment solution of 2.5 mol / L sodium hydroxide and 0.4 mol / L sodium sulfite for 6 hours at 80°C. Then rinse it with deionized water and set aside for use. (This removes nutrients such as sugar and starch from the bamboo and increases the porosity of the wood.)

[0028] 3) Soak the alkaline-pretreated bamboo in MA (maleic anhydride) dissolved in toluene for 3-6 hours; then soak it in a vacuum impregnation (>0.1MPa) solution containing a reinforcing anti-rebound resin solution for a period of time (>1 hour), remove it, remove the surface resin and set aside for use.

[0029] 4) Place the product from step 1) above the product from step 3), and place the bamboo containing fluorine oxide metal oxide co-doped glass powder above the negative pressure machine and adjust the air pressure to -100Mpa for 30 minutes.

[0030] 5) After mixing the products from step 4), place them in a freeze dryer and pre-freeze them to -60°C. Then, dry them under vacuum. After drying, place them in a helium tube furnace for carbonization to obtain the final product, microcrystalline glass / porous fiber anode material.

[0031] Example 2

[0032] Preparation of a microcrystalline glass / porous fiber anode material

[0033] 1) Using GeO2-B2O3-PbO-Cs2CO3-PbBr-NaBr-SnF2-GeO oxide powders in a mass ratio of 2:5:0.2:12:0.75:0.8:0.93:0.93 as starting material, after thorough mixing, the batch was placed in an alumina crucible and melted in an electric furnace at 780℃ for 30 minutes. It was then removed, cold-extracted, and annealed at 300℃. It was then placed in a glass melting furnace for remelting at 1200℃ for 2 hours. After 2 hours, the temperature was lowered to 200℃ and held constant for 0.5 hours under a helium atmosphere.

[0034] 2) Take porous bamboo and soak it in a mixed alkaline treatment solution of 2.5 mol / L sodium hydroxide and 0.4 mol / L sodium sulfite for 6 hours at 80°C. Then rinse it with deionized water and set aside for use. (This removes nutrients such as sugar and starch from the bamboo and increases the porosity of the wood.)

[0035] 3) Soak the bamboo pretreated with alkaline solution in MA (maleic anhydride) dissolved in toluene for 3-6 hours; then place it in a vacuum impregnation chamber containing a reinforcing anti-rebound resin solution with a pressure greater than 0.1 MPa for a period of time greater than 1 hour, remove it, remove the surface resin and set aside for use.

[0036] 4) Place the product from step 1) above the product from step 3), and place the bamboo containing fluorine oxide metal oxide co-doped glass powder above the negative pressure machine and adjust the air pressure to -100Mpa for 30 minutes.

[0037] 5) After mixing the products from step 4), place them in a freeze dryer and pre-freeze them to -60°C. Then, dry them under vacuum. After drying, place them in a helium tube furnace for carbonization to obtain the final product, microcrystalline glass / porous fiber anode material.

[0038] Example 3

[0039] Preparation of a microcrystalline glass / porous fiber anode material

[0040] 1) Using GeO2-B2O3-PbO-Cs2CO3-PbBr-NaBr-SnF2-SnO powder in a mass ratio of 2:5:0.2:0.7:0.9:0.8:1.2:0.93 as the starting material, after thorough mixing, the batch was placed in an alumina crucible and melted in an electric furnace at 780℃ for 30 minutes. It was then removed, cold-extracted, and annealed at 300℃. It was then placed in a glass melting furnace for remelting at 1200℃ for 2 hours. After 2 hours, the temperature was lowered to 200℃ and held constant for 0.5 hours under a helium atmosphere.

[0041] 2) Take porous bamboo and soak it in a mixed alkaline treatment solution of 2.5 mol / L sodium hydroxide and 0.4 mol / L sodium sulfite for 6 hours at 80°C. Then rinse it with deionized water and set aside for use. (This removes nutrients such as sugar and starch from the bamboo and increases the porosity of the wood.)

[0042] 3) Soak the bamboo pretreated with alkaline solution in MA (maleic anhydride) dissolved in toluene for 3-6 hours; then place it in a vacuum impregnation chamber containing a reinforcing anti-rebound resin solution at a pressure of less than 0.1 MPa for a period of more than 1 hour. Remove the bamboo and remove the surface resin before use.

[0043] 4) Place the product from step 1) above the product from step 3), and place the bamboo containing fluorine oxide metal oxide co-doped glass powder above the negative pressure machine and adjust the air pressure to -100Mpa for 30 minutes.

[0044] 5) After mixing the products from step 4), place them in a freeze dryer and pre-freeze them to -60°C. Then, dry them under vacuum. After drying, place them in a helium tube furnace for carbonization to obtain the final product, microcrystalline glass / porous fiber anode material.

[0045] Comparative Example 1: The porous fibers in Example 3 were removed, and the other steps were exactly the same as in Example 3.

[0046] Comparative Example 2: The fluoride oxides in Example 3 were removed, and all other steps were exactly the same as in Example 3.

[0047] Electrochemical performance testing of electrode materials:

[0048] Preparation of working electrode: Using the active materials from Examples 1, 2, 3, Comparative Examples 4, and 5, acetylene black as a conductive agent, and polyvinylidene fluoride (PVDF) as a binder, the materials were mixed and ground uniformly in a mass ratio of 8:1:1. An appropriate amount of N-methyl-2-pyrrolidone (NMP) was added, and the mixture was stirred into a slurry. This slurry was then uniformly coated onto copper foil and dried in a vacuum drying oven at 110°C for 12 hours. The electrode was then cut into pieces with a diameter of 12 mm and a loading of approximately 2 mg / cm². 2 Electrode plates.

[0049] Lithium-ion battery assembly and performance testing: Using the aforementioned polypyrrole carbon fiber-supported tin disulfide nanoelectrode sheet as the working electrode, a lithium metal sheet as the counter electrode, glass fiber (GF / D, Whatman) as the separator, and a mixture of ethylene carbonate (EC) and dimethyl carbonate (DMC) in 1 mol / L NaClO4 (volume ratio 1:1) as the electrolyte, CR2016 coin cells were assembled in an argon-filled glove box. The constant current charge-discharge performance and CV test of the battery were tested using a LAND CT2001A battery testing system. The charge-discharge voltage range was 0.01–3.0V. The constant current charge-discharge test results are as follows:

[0050]

[0051]

[0052] Tests such as Figure 2 As shown, a cubic structure is formed inside the material after 1500 cycles, and the cycle life is much longer than that of the anode materials of Comparative Example 1 and Comparative Example 2.

[0053] Although embodiments of the invention have been shown and described with comparative examples, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A microcrystalline glass / porous fiber negative electrode material, characterized in that The microcrystalline glass is a fluorine-oxygen metal oxide co-doped microcrystalline glass, the microcrystalline glass is composed of GeO2, H3BO3, PbO, CsCO3, PbBr2, NaBr, fluoride and oxide, the mass ratio of each component is GeO2:H3BO3:PbO:CsCO3:PbBr2:NaBr:fluoride:oxide is (2-12):(3-5):(0.2-1.3):(0.3-0.7):(0.6-0.75):(0.5-0.8):(0.8-0.93):(0.8-0.93), the fluoride is stannous fluoride, and the oxide is at least one of stannous oxide, germanium oxide and selenium oxide, the microcrystalline glass has an amorphous network structure, and the amorphous network structure contains a stable perovskite structure, the porous fiber is a bamboo carbon fiber, the inside has a mesoporous structure, the microcrystalline glass powder is embedded into the inside of the bamboo by a negative pressure adsorption method, and then carbonization is performed, and finally a microcrystalline glass / porous fiber negative electrode material is obtained.

2. The glass-ceramic / porous fiber negative electrode material according to claim 1, characterized in that: The perovskite structure is a bromine lead cesium-based perovskite, and the structure generates CsPF6 in a cubic structure in the charging and discharging process.

3. A method for preparing the glass-ceramic / porous fiber negative electrode material according to claim 1, characterized in that The method comprises the following steps: 1) The components of the microcrystalline glass are weighed according to the mass ratio, mixed thoroughly, put into an alumina crucible, melted in an electric furnace at 780 DEG C for 30 minutes, taken out, cold leached, annealed at 300 DEG C, put into a glass melting furnace again, melted at a melting temperature of 1200 DEG C for 2 hours, then lowered to 200 DEG C for 0.5 hours, protected by a helium atmosphere, cooled to room temperature, and ground into powder; 2) The porous bamboo is immersed in a prepared mixed alkali treatment solution, and then washed with deionized water for use; 3) The bamboo treated with the alkali solution is immersed in maleic anhydride dissolved in toluene for 3-6 hours, then put into a reinforced anti-rebound resin solution, vacuum soaked at a pressure greater than 0.1 MPa for more than 1 hour, and then removed from the surface of the resin for use; 4) The powder obtained in step 1) and the product in step 3) are uniformly mixed, placed above a negative pressure machine, and the pressure is adjusted to-100 MPa for 30 minutes; 5) The product in step 4) is pre-frozen to-60 DEG C in a freeze dryer, then vacuum dried, and finally carbonized in a helium tube furnace to obtain the final product, a microcrystalline glass / porous fiber negative electrode material.

4. The method of claim 3, wherein: In step 2), the alkali solution is a mixed solution of 2.5 mol / L sodium hydroxide and 0.4 mol / L sodium sulfite, the soaking temperature is 80 DEG C, and the soaking time is 6 hours.

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