A method for modifying silicon-based anode materials
By modifying nano-silicon with phosphorus-containing modifiers and soybeans as a carbon source, frozen tofu-coated silicon-based materials were prepared, solving the problem of severe pulverization of silicon-based anode materials during charge and discharge, and improving their cycle performance and electrochemical performance.
Patent Information
- Application Number
- CN202310923263.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-07-25
- Publication Date
- 2025-10-31
- Estimated Expiration
- 2043-07-25
AI Technical Summary
Existing silicon-based anode materials suffer from severe pulverization during charge and discharge, resulting in poor battery cycle performance.
Nano-silicon was modified using a phosphorus-containing modifier and soybean as a carbon source. By preparing frozen tofu to coat silicon-based materials, a solid electrolyte membrane with excellent electrochemical performance was formed, thus improving the volume expansion problem.
This improves the volume expansion problem of nano-silicon during charge and discharge, and enhances the cycle performance and electrochemical performance of nano-silicon.
Smart Images
Figure CN116706038B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of material modification technology, specifically to a method for modifying silicon-based anode materials. Background Technology
[0002] With the increasing maturity of electronic device technology, people have higher and higher requirements for batteries, not only pursuing higher capacity but also placing greater emphasis on battery performance in terms of safety and environmental friendliness. Compared with other rechargeable batteries, lithium-ion batteries are lighter, resulting in higher energy density and greater portability. Lithium-ion batteries have higher specific capacity and longer cycle life. In addition, lithium-ion batteries do not contain toxic heavy metals, making them more environmentally friendly and safer. Due to these many advantages, lithium-ion batteries have been widely used in the battery industry.
[0003] However, the lithium battery industry still faces some challenges. The most pressing demand for lithium-ion batteries is high energy density, which existing commercial batteries cannot meet. Therefore, developing novel high-capacity anode materials is imperative. Silicon has an extremely high specific capacity, more than ten times that of carbon-based materials, which is why silicon-based materials are considered the most promising new anode materials. However, silicon anodes suffer from severe pulverization during charging and discharging, leading to poor battery cycle performance. Therefore, modifying silicon-based materials to improve silicon electrode expansion is currently one of the hot topics in lithium-ion battery anode material research. Summary of the Invention
[0004] This invention provides a method for modifying silicon-based anode materials, which solves the problem of poor battery cycle performance caused by severe silicon electrode pulverization during charging and discharging of existing silicon anodes.
[0005] To solve the above-mentioned technical problems, the technical solution provided by the present invention is as follows:
[0006] A method for modifying silicon-based anode materials, comprising modifying nano-silicon with a phosphorus-containing modifier and soybean as a carbon source, characterized by the following steps:
[0007] (1) Add ethanol to an aqueous solution containing phosphorus modifier, stir magnetically, then add nano-silicon, and disperse evenly to obtain a mixed solution;
[0008] (2) The mixed solution was evenly coated onto a glass plate with a scraper, dried and ground into fine powder, and then sieved to obtain a phosphorus-containing binder-modified silicon-based material.
[0009] (3) Weigh out soybeans and make soy milk;
[0010] (4) Weigh out the phosphorus-containing binder-modified silicon-based material, conductive slurry, asphalt, carbon nanotubes, CTAB and HEDP respectively and add them to a beaker. Perform ultrasonic and high-speed homogenization to obtain well dispersed materials.
[0011] (5) Add the dispersed material to the soy milk, boil and cool it, then quickly add it to the lactone. After the reaction, sieve, filter and press to obtain the tofu-coated silicon-based material. Freeze in the refrigerator and dry for one day to obtain the frozen tofu-coated silicon-based material.
[0012] (6) Grind the silicon-based material coated with frozen tofu into powder and sieve it. Sinter it in a tube furnace. Grind the sintered material into powder and sieve it to obtain frozen tofu modified silicon-based anode material.
[0013] The phosphorus-containing modifier is hydroxyethylidene diphosphate (HEDP), aminotrimethylenephosphonic acid (ATMP), or 2-phospho-1,2,4-tricarboxylic acid butane (PBTCA).
[0014] In step (1), the mass percentage concentration of the phosphorus-containing modifier aqueous solution is 50-70%, and the mass ratio of nano-silicon, phosphorus-containing modifier and ethanol is 1:(0.04-0.045):(2.2-2.5).
[0015] In step (2), the drying temperature is 50-70℃ and the drying time is 10-15 hours. The powder is ground into fine powder in an agate mortar and passed through a 200-mesh sieve.
[0016] In step (3), the process of preparing soy milk is as follows: 15g of soybeans are placed in a beaker and soaked in distilled water for 8 hours. After soaking, the soybeans are poured into a blender, 100mL of distilled water is added, and the blender is blended for 3 minutes. The soybean residue on the machine wall is rinsed with distilled water. The process is repeated twice to obtain raw soy milk. The raw soy milk is then passed through a 100-mesh sieve and heated to boiling in an infrared heating furnace.
[0017] In step (4), the ratio of phosphorus-containing binder modified silicon-based material, conductive slurry, asphalt, carbon nanotubes, CTAB and HEDP is 10:1:1:1:1:1, and the high-speed homogenization speed is 5000 r / min.
[0018] In step (5), the lactone is gluconic acid-δ-lactone; boiling and cooling is to heat while stirring for 30 minutes and cool to 85-95℃; filtration is to lay a layer of gauze on a 50-mesh sieve, pour the mixture into the 50-mesh sieve, and compact the filter residue to obtain the formed tofu coated with silicon-based material.
[0019] In step (6), the sample is passed through a 100-mesh sieve before sintering and through a 200-mesh sieve after sintering. The sintering temperature is 900℃ and the sintering time is 6 hours.
[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0021] To extend the cycle life and improve the electrochemical performance of silicon-based materials, this invention employs two methods to modify nano-silicon: first, a silicon-based anode material is prepared by mixing a phosphorus-containing modifier with nano-silicon; second, frozen tofu is prepared by coating nano-silicon with soybeans as a carbon source. The modified nano-silicon material forms a solid electrolyte membrane with excellent electrochemical performance, mitigating the volume expansion problem during charge and discharge. Button battery testing revealed improved cycle performance and electrochemical performance of the modified nano-silicon. Attached Figure Description
[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0023] Figure 1 The silicon-based anode material SEM was prepared by mixing the phosphorus-containing modifier HEDP obtained in Example 1 with nano-silicon.
[0024] Figure 2 The specific capacity-voltage curve of the silicon-based anode material prepared by mixing the phosphorus-containing modifier obtained in Example 1 with nano-silicon is shown in the figure.
[0025] Figure 3 The specific capacity-voltage curve of silicon-based anode material prepared by mixing the phosphorus-containing binder HEDP obtained in Example 2 without the stirring and drying process with nano-silicon is shown in the figure.
[0026] Figure 4 These are cycle images of the four silicon-based anode materials prepared in Examples 3, 4, 5, and 6.
[0027] Figure 5 These are the specific capacity-voltage curves of the four silicon-based anode materials prepared in Examples 3, 4, 5, and 6.
[0028] Figure 6 These are the specific capacity-voltage curves of the four silicon-based anode materials prepared in Examples 3, 4, 5, and 7. Detailed Implementation
[0029] The technical solution of the invention will be clearly and completely described below with reference to the embodiments of the invention. Obviously, the described embodiments are only some embodiments of the invention, and not all embodiments. Based on the embodiments of the invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the invention.
[0030] Example 1
[0031] This embodiment provides a method for modifying silicon-based anode materials by mixing phosphorus-containing binders with nano-silicon, comprising the following steps:
[0032] (1) Dissolve 0.18g HEDP in 0.12g distilled water to prepare 0.3g of HEDP aqueous solution with a mass fraction of 60%. Then dissolve 0.3g of 60% HEDP aqueous solution in 9.7g ethanol. Stir with a magnetic stirrer for 30min at room temperature. Weigh 7g of the solution into a small beaker for later use.
[0033] (2) Weigh 3g of nano-silicon, disperse the nano-silicon into a small beaker containing 7g of HEDP solution, stir the homogeneous solution, and continue stirring for 5 hours to form a homogeneous mixture.
[0034] (3) After stirring, the mixture was evenly spread on a glass plate with a spatula and dried at 60°C for 12 hours. The dried powder was scraped off the glass plate, ground into fine powder in an agate mortar, and passed through a 200-mesh sieve. The resulting sample was named Si@HEDP. Si@ATMP and Si@PBTCA were then prepared using the same method for later use.
[0035] This example uses three phosphorus-containing modifiers to modify nano-silicon, preparing three silicon-based anode materials: Si@HEDP, Si@ATMP, and Si@PBTCA. Among them, the silicon-based anode material prepared by mixing the phosphorus-containing modifier HEDP with nano-silicon is shown in the SEM image. Figure 1 As shown, the specific capacity-voltage curves of silicon-based anode materials prepared by mixing three phosphorus-containing modifiers with nano-silicon are as follows. Figure 2 As shown, all three materials exhibit high initial discharge specific capacity. Si@HEDP achieves an initial discharge specific capacity of 3407.51 mAh / g and an initial charge-discharge efficiency of 94.55%, demonstrating good cycle performance and high capacity.
[0036] Example 2
[0037] This embodiment provides a method for modifying silicon-based anode materials by mixing a phosphorus-containing modifier with nano-silicon, comprising the following steps:
[0038] (1) Dissolve 0.18g HEDP in 0.12g distilled water to prepare 0.3g of HEDP aqueous solution with a mass fraction of 60%, then dissolve 0.3g of 60% HEDP aqueous solution in 9.7g ethanol and stir with a magnetic stirrer for 30min at room temperature;
[0039] (2) Weigh 3g of nano-silicon and disperse it in a small beaker containing 7g of HEDP solution. Stir the mixture until it becomes homogeneous, and continue stirring for 5 hours to form a homogeneous mixture. The resulting sample is denoted as Si+HEDP.
[0040] The specific capacity-voltage curve of the silicon-based anode material prepared in this embodiment is shown in the figure below. Figure 3 As shown.
[0041] Although the discharge specific capacity of the material prepared by adding a phosphorus-containing solvent to nano-silicon during homogenization in this example is slightly lower than that of Si@HEDP, its cycle stability is stronger. Therefore, HEDP has a better modification effect on nano-silicon, indicating that HEDP helps to improve the poor cycle performance of nano-silicon.
[0042] Example 3
[0043] This embodiment provides a method for modifying nano-silicon materials by coating them with tofu powder, including the following steps:
[0044] (1) Weigh 15g of dried soybeans and grind them into powder in a grinder. Add 200ml of distilled water to dissolve them completely, then filter to obtain a finer raw soy milk. Boil the soy milk at 300W on an induction cooker.
[0045] (3) Weigh 5.0g of nano-silicon, 0.5g of conductive paste, 0.5g of carbon nanotubes and 0.5g of CTAB in a beaker at a ratio of 10:1:1:1. Sonicate the weighed materials in an ultrasonic cleaner for 15 minutes, and then homogenize them at high speed 3 times for 3 minutes each time to obtain well dispersed materials.
[0046] (4) The nano-silicon obtained by boiling soy milk and dispersing is placed in a 1L beaker and stirred for 30 minutes under the heating condition of 150W induction cooker. Then, 3g of lactone is added, and after half a minute, it is dried in an oven at 60℃ (3 to 5 days).
[0047] (5) Grind the tofu powder into powder in an agate mortar and pass it through a 100-mesh molecular sieve. Place the ground material into a boat and put it into a tube furnace, and calcine it at 900°C for 6 hours. Grind the calcined material into powder and pass it through a 200-mesh molecular sieve to obtain the tofu powder coated silicon-based material.
[0048] In this example, the initial discharge specific capacity of the nano-silicon coated with soybean powder is 387.58 mAh / g, the initial discharge specific capacity is 229.49 mAh / g, and the charge-discharge efficiency is 59.21%.
[0049] Example 4
[0050] This embodiment provides a method for modifying nano-silicon materials by coating conventional tofu, including the following steps:
[0051] (1) Weigh 15g of soybeans into a beaker and soak them in an appropriate amount of distilled water for 8 hours. After soaking, pour the soybeans into a blender, add 100mL of distilled water to the blender, blend for 3 minutes, then turn it on and rinse the remaining soybean residue on the machine wall with distilled water. Then blend the soybeans again and repeat the above operation twice, blending for 3 minutes each time to obtain raw soybean milk.
[0052] (2) Pass the prepared soy milk through a 100-mesh molecular sieve, then heat it to a boil in an infrared heating furnace and set aside for use. Finally, rinse the filtered soy pulp with distilled water, place it in a small beaker, and put it in a drying oven to dry for one day. After drying, weigh the soy pulp.
[0053] (3) Weigh 5.0g of nano-silicon, 0.5g of conductive paste, 0.5g of carbon nanotubes and 0.5g of CTAB in a beaker at a ratio of 10:1:1:1. Place the weighed materials in an ultrasonic cleaner and sonicate for 15 minutes. Then perform high-speed homogenization 3 times, 3 minutes each time, to obtain well dispersed materials.
[0054] (4) Add the dispersed nano-silicon to the boiled soy milk. Rinse the beaker walls with distilled water to ensure all material is rinsed into the soy milk. Heat for 30 minutes while stirring, observing the temperature of the soy milk frequently during heating. After heating, quickly remove the soy milk from the infrared heater and cool it to about 90°C. While cooling the soy milk, open a packet of glucono-delta-lactone (GDL) and pour it into a small beaker. Add a small amount of distilled water to dissolve it. After the soy milk has cooled, quickly add the GDL in a circular motion while stirring slowly. Rinse the remaining GDL in the small beaker into the soy milk with distilled water. Continue stirring slowly until tofu settles. Wait for the GDL to react completely with the soy milk. Place a layer of gauze on a 50-mesh molecular sieve, pour the soy milk into the molecular sieve, filter out the tofu, and press it to obtain shaped tofu. Dry in a drying oven for one day to obtain conventional tofu coated with silicon-based material.
[0055] (5) Grind the conventional tofu-coating silicon-based material into powder in an agate mortar and pass it through a 100-mesh molecular sieve. Place the ground material into a boat and put it into a tube furnace, where it is heated at 900°C for 6 hours. Grind the heated material into powder and pass it through a 200-mesh molecular sieve to obtain the conventional tofu material.
[0056] In this example, the initial discharge specific capacity of the modified silicon-based material coated with conventional tofu was 610.46 mAh / g, the initial charge specific capacity was 405.28 mAh / g, and the charge-discharge efficiency was 66.39%, indicating that the molding of tofu makes the modified silicon-based material perform better than soybean powder.
[0057] Example 5
[0058] This embodiment provides a method for modifying nano-silicon materials by coating frozen tofu, comprising the following steps:
[0059] (1) Weigh 15g of soybeans into a beaker and soak them in an appropriate amount of distilled water for 8 hours. After soaking, pour the soybeans into a blender, add 100mL of distilled water to the blender, blend for 3 minutes, then turn it on and rinse the remaining soybean residue on the machine wall with distilled water. Then blend the soybeans again and repeat the above operation twice, blending for 3 minutes each time to obtain raw soybean milk.
[0060] (2) Pass the prepared soy milk through a 100-mesh molecular sieve, then heat it to a boil in an infrared heating furnace and set aside for use. Finally, rinse the filtered soy pulp with distilled water, place it in a small beaker, and put it in a drying oven to dry for one day. After drying, weigh the soy pulp.
[0061] (3) Weigh nano-silicon, conductive paste, carbon nanotubes, CTAB and HEDP in a beaker at a ratio of 10:1:1:1:1. Sonicate the weighed materials in an ultrasonic cleaner for 15 minutes, and then homogenize them three times at high speed for 3 minutes each time to obtain well dispersed materials.
[0062] (4) Add the dispersed nano-silicon to the boiled soy milk. Rinse the beaker walls with distilled water to ensure all material is incorporated into the soy milk. Heat for 30 minutes while stirring, observing the temperature of the soy milk frequently during heating. After heating, quickly remove the soy milk from the infrared heater and cool it to approximately 90°C. While cooling, open a packet of glucono-delta-lactone (GDL) and pour it into a small beaker. Dissolve it in a small amount of distilled water. Once the soy milk has cooled, quickly add the GDL in a circular motion while stirring slowly. Rinse the remaining GDL in the small beaker with distilled water into the soy milk. Continue stirring slowly until tofu settles. Allow the GDL to react completely with the soy milk. Place a layer of gauze on a 50-mesh molecular sieve, pour the soy milk into the sieve, filter out the tofu, and press it to obtain shaped tofu. Finally, freeze the tofu in a refrigerator. After freezing, remove it and dry it in a drying oven for one day to obtain the silicon-based material coated on the frozen tofu.
[0063] (5) Grind the silicon-based material coating the frozen tofu into powder in an agate mortar and pass it through a 100-mesh molecular sieve. Place the ground material into a boat and put it into a tube furnace, where it is heated at 900°C for 6 hours. Grind the heated material into powder and pass it through a 200-mesh molecular sieve to obtain the frozen tofu material.
[0064] In this example, the initial discharge specific capacity of the frozen tofu-coated nano-silicon material was 1337.04 mAh / g, the initial charge specific capacity was 1102.10 mAh / g, and the charge-discharge efficiency was 82.43%. The discharge specific capacity of the tofu-coated nano-silicon material was much higher than that of conventional tofu and soybean flour-coated nano-silicon. Moreover, the capacity of the frozen tofu-coated nano-silicon did not decrease significantly after the first discharge, indicating that the frozen tofu coating alleviated the volume expansion problem of nano-silicon. The frozen tofu had a much higher specific capacity than the conventional tofu, indicating that the internal porosity of the frozen tofu increased, which affected the material's discharge performance.
[0065] Example 6
[0066] This embodiment provides a method for modifying nano-silicon materials by coating frozen tofu with asphalt, including the following steps:
[0067] (1) Weigh 15g of soybeans into a beaker and soak them in an appropriate amount of distilled water for 8 hours. After soaking, pour the soybeans into a blender, add 100mL of distilled water to the blender, blend for 3 minutes and then turn it on to obtain raw soy milk with distilled water.
[0068] (2) Pass the prepared soy milk through a 100-mesh molecular sieve, then heat it to a boil in an infrared heating furnace and set aside for use. Finally, rinse the filtered soy pulp with distilled water, place it in a small beaker, and put it in a drying oven to dry for one day. After drying, weigh the soy pulp.
[0069] (3) Weigh nano-silicon, conductive slurry, asphalt, carbon nanotubes, CTAB and HEDP in a beaker according to the ratio of 10:1:1:1:1:1. Place the weighed materials in an ultrasonic cleaner and sonicate for 15 minutes. Then perform high-speed homogenization 3 times, 3 minutes each time, to obtain well dispersed materials.
[0070] (4) Add the dispersed nano-silicon to the boiled soy milk. Rinse the beaker walls with distilled water to ensure all material is incorporated into the soy milk. Heat for 30 minutes while stirring, observing the temperature of the soy milk frequently during heating. After heating, quickly remove the soy milk from the infrared heater and cool it to approximately 90°C. While cooling, open a packet of glucono-delta-lactone (GDL) and pour it into a small beaker. Dissolve it in a small amount of distilled water. Once the soy milk has cooled, quickly add the GDL in a circular motion while stirring slowly. Rinse the remaining GDL in the small beaker with distilled water into the soy milk. Continue stirring slowly until tofu settles. Allow the GDL to react completely with the soy milk. Place a layer of gauze on a 50-mesh molecular sieve, pour the soy milk into the sieve, filter out the tofu, and press it to obtain shaped tofu. Finally, freeze the tofu in a refrigerator. After freezing, remove it and dry it in a drying oven for one day to obtain the silicon-based material coated on the frozen tofu.
[0071] (5) Grind the silicon-based material coating the frozen tofu into powder in an agate mortar and pass it through a 100-mesh molecular sieve. Place the ground material into a boat and put it into a tube furnace, where it is heated at 900°C for 6 hours. Grind the heated material into powder and pass it through a 200-mesh molecular sieve to obtain the frozen tofu material.
[0072] The cycling images of the four silicon-based anode materials prepared in Examples 3, 4, 5, and 6 are shown below. Figure 4 As shown; the specific capacity-voltage curves of the four silicon-based anode materials prepared in Examples 3, 4, 5, and 6 are shown in the figure. Figure 5 As shown.
[0073] In this example, the initial discharge specific capacity of the frozen tofu coated with asphalt was 1742.61 mAh / g, the initial charge specific capacity was 1546.30 mAh / g, and the charge-discharge efficiency was 88.74%. The discharge specific capacity of the nano-silicon material coated with frozen tofu was higher than that of nano-silicon coated with conventional tofu and soybean powder. Because asphalt provides more carbon source, the initial discharge specific capacity of the material after adding asphalt to tofu was higher.
[0074] Example 7
[0075] This embodiment provides a method for modifying silicon-based anode materials, using a phosphorus-containing modifier and soybean as a carbon source to modify nano-silicon, including the following steps:
[0076] (1) Dissolve 0.18g HEDP in 0.12g distilled water to prepare 0.3g of HEDP aqueous solution with a mass fraction of 60%. Then dissolve 0.3g of 60% HEDP aqueous solution in 9.7g ethanol. Stir with a magnetic stirrer for 30min at room temperature. Weigh 7g of the solution into a small beaker for later use.
[0077] (2) Weigh 3g of nano-silicon, disperse the nano-silicon into a small beaker containing 7g of HEDP solution, stir the homogeneous solution, and continue stirring for 5 hours to form a homogeneous mixture.
[0078] (3) After stirring, use a scraper to evenly spread the mixture on a glass plate and dry it at 60°C for 12 hours; scrape the dried powder off the glass plate, grind it into fine powder in an agate mortar, pass it through a 200-mesh sieve, and record the obtained sample as phosphorus-containing binder modified silicon-based material.
[0079] (4) Weigh 15g of soybeans into a beaker and soak them in an appropriate amount of distilled water for 8 hours. After soaking, pour the soybeans into a blender, add 100mL of distilled water to the blender, blend for 3 minutes, then turn it on and rinse the remaining soybean residue on the machine wall with distilled water. Repeat the operation twice to obtain raw soy milk.
[0080] (5) Pass the prepared soy milk through a 100-mesh molecular sieve, then heat it to a boil in an infrared heating furnace and set aside for use. Finally, rinse the filtered soy pulp with distilled water, place it in a small beaker, and put it in a drying oven to dry for one day. After drying, weigh the soy pulp.
[0081] (6) Weigh out the phosphorus-containing binder-modified silicon-based material, conductive slurry, asphalt, carbon nanotubes, CTAB and HEDP in a beaker according to the ratio of 10:1:1:1:1:1. Place the weighed materials in an ultrasonic cleaner and sonicate for 15 minutes. Then perform high-speed homogenization 3 times. The high-speed homogenization speed is 5000 r / min, and each time is 3 minutes to obtain well dispersed materials.
[0082] (7) Add the dispersed nano-silicon to the boiled soy milk. Rinse the beaker walls with distilled water to ensure all material is incorporated into the soy milk. Heat for 30 minutes while stirring, observing the temperature of the soy milk frequently during heating. After heating, quickly remove the soy milk from the infrared heater and cool it to approximately 90°C. While cooling, open a packet of glucono-delta-lactone (GDL) and pour it into a small beaker. Dissolve it in a small amount of distilled water. Once the soy milk has cooled, quickly add the GDL in a circular motion while stirring slowly. Rinse the remaining GDL in the small beaker with distilled water into the soy milk. Continue stirring slowly until tofu settles. Allow the GDL to react completely with the soy milk. Place a layer of gauze on a 50-mesh molecular sieve, pour the soy milk into the sieve, filter out the tofu, and press it to obtain shaped tofu. Finally, freeze the tofu in a refrigerator. After freezing, remove it and dry it in a drying oven for one day to obtain the silicon-based material coated on the frozen tofu.
[0083] (8) Grind the silicon-based material coating the frozen tofu into powder in an agate mortar, pass it through a 100-mesh sieve, put the ground material into a boat and place it in a tube furnace, and burn it at 900°C for 6 hours. Grind the burned material into powder and pass it through a 200-mesh sieve to obtain the frozen tofu material.
[0084] The specific capacity-voltage curve of the silicon-based anode material prepared in this embodiment is shown in the figure below. Figure 6 As shown.
[0085] Example 8
[0086] This embodiment provides a method for modifying silicon-based anode materials, using a phosphorus-containing modifier and soybean as a carbon source to modify nano-silicon, including the following steps:
[0087] (1) Dissolve 0.12g HEDP in 0.12g distilled water to prepare 0.24g of 50% HEDP aqueous solution. Then dissolve 0.24g of 60% HEDP aqueous solution in 7.5g ethanol and stir with a magnetic stirrer for 30min at room temperature.
[0088] (2) Weigh 3g of nano-silicon, disperse the nano-silicon into a small beaker of EDP solution, stir the homogeneous solution, and continue stirring for 5 hours to form a homogeneous mixture.
[0089] (3) After stirring, use a scraper to evenly spread the mixture on a glass plate and dry it at 70°C for 10 hours; scrape the dried powder off the glass plate, grind it into fine powder in an agate mortar, pass it through a 200-mesh sieve, and the resulting sample is recorded as phosphorus-containing binder modified silicon-based material.
[0090] (4) Weigh 15g of soybeans into a beaker and soak them in an appropriate amount of distilled water for 8 hours. After soaking, pour the soybeans into a blender, add 100mL of distilled water to the blender, blend for 3 minutes, then turn it on and rinse the remaining soybean residue on the machine wall with distilled water. Repeat the operation twice to obtain raw soy milk.
[0091] (5) Pass the prepared soy milk through a 100-mesh molecular sieve, then heat it to a boil in an infrared heating furnace and set aside for use. Finally, rinse the filtered soy pulp with distilled water, place it in a small beaker, and put it in a drying oven to dry for one day. After drying, weigh the soy pulp.
[0092] (6) Weigh out phosphorus-containing binder-modified silicon-based material, conductive slurry, asphalt, carbon nanotubes, CTAB and HEDP in a beaker at a ratio of 10:1:1:1:1:1. Place the weighed materials in an ultrasonic cleaner and sonicate for 15 minutes. Then perform high-speed homogenization 3 times at a speed of 5000 r / min for 3 minutes each time to obtain well dispersed materials.
[0093] (7) Add the dispersed nano-silicon to the boiled soy milk. Rinse the beaker walls with distilled water to ensure all the material is rinsed into the soy milk. Heat for 30 minutes while stirring, and observe the temperature of the soy milk frequently during the heating process. After heating, quickly remove the soy milk from the infrared heater and cool it to about 80°C. While cooling the soy milk, open a packet of glucono-delta-lactone (GDL) and pour it into a small beaker. Add a small amount of distilled water to dissolve it. After the soy milk has cooled, quickly add the GDL in a circular motion while stirring slowly. Rinse the remaining GDL in the small beaker into the soy milk with distilled water. Continue stirring slowly until tofu settles. Wait for the GDL to react completely with the soy milk. Place a layer of gauze on a 50-mesh molecular sieve, pour the soy milk into the molecular sieve, filter out the tofu, and press it to obtain the formed tofu. Finally, put the prepared tofu in the refrigerator to freeze. After freezing, take it out and dry it in a drying oven for one day to obtain the silicon-based material coated on the frozen tofu.
[0094] (8) Grind the silicon-based material coating the frozen tofu into powder in an agate mortar, pass it through a 100-mesh sieve, put the ground material into a boat and place it in a tube furnace, and burn it at 900°C for 6 hours. Grind the burned material into powder and pass it through a 200-mesh sieve to obtain the frozen tofu material.
[0095] The specific capacity-voltage curve of the silicon-based anode material prepared in this embodiment is not significantly different from that in Example 7.
[0096] Example 9
[0097] This embodiment provides a method for modifying silicon-based anode materials, using a phosphorus-containing modifier and soybean as a carbon source to modify nano-silicon, including the following steps:
[0098] (1) Dissolve 0.135g HEDP in 0.19g distilled water to prepare 0.325g of HEDP aqueous solution with a mass fraction of 70%, and then dissolve 0.325g of 60% HEDP aqueous solution in 6.6g ethanol. Stir with a magnetic stirrer for 30min at room temperature.
[0099] (2) Weigh 3g of nano-silicon, disperse the nano-silicon into a small beaker of HEDP solution, stir the homogeneous solution, and continue stirring for 5 hours to form a homogeneous mixture.
[0100] (3) After stirring, use a scraper to evenly spread the mixture on a glass plate and dry it at 50°C for 15 hours; scrape the dried powder off the glass plate, grind it into fine powder in an agate mortar, pass it through a 200-mesh sieve, and record the obtained sample as phosphorus-containing binder modified silicon-based material.
[0101] (4) Weigh 15g of soybeans into a beaker and soak them in an appropriate amount of distilled water for 8 hours. After soaking, pour the soybeans into a blender, add 100mL of distilled water to the blender, blend for 3 minutes, then turn it on and rinse the remaining soybean residue on the machine wall with distilled water. Repeat the operation twice to obtain raw soy milk.
[0102] (5) Pass the prepared soy milk through a 100-mesh molecular sieve, then heat it to a boil in an infrared heating furnace and set aside for use. Finally, rinse the filtered soy pulp with distilled water, place it in a small beaker, and put it in a drying oven to dry for one day. After drying, weigh the soy pulp.
[0103] (6) Weigh out phosphorus-containing binder-modified silicon-based material, conductive slurry, asphalt, carbon nanotubes, CTAB and HEDP in a beaker at a ratio of 10:1:1:1:1:1. Place the weighed materials in an ultrasonic cleaner and sonicate for 15 minutes. Then perform high-speed homogenization 3 times at a speed of 5000 r / min for 3 minutes each time to obtain well dispersed materials.
[0104] (7) Add the dispersed nano-silicon to the boiled soy milk. Rinse the beaker walls with distilled water to ensure all material is incorporated into the soy milk. Heat for 30 minutes while stirring, observing the temperature of the soy milk frequently during heating. After heating, quickly remove the soy milk from the infrared heater and cool it to approximately 95°C. While cooling the soy milk, open a packet of glucono-delta-lactone (GDL) and pour it into a small beaker. Dissolve it in a small amount of distilled water. After the soy milk has cooled, quickly add the GDL in a circular motion while stirring slowly. Rinse the remaining GDL in the small beaker with distilled water into the soy milk. Continue stirring slowly until tofu settles. Let it stand until the GDL reacts completely with the soy milk. Place a layer of gauze on a 50-mesh molecular sieve, pour the soy milk into the sieve, filter out the tofu, and press it to obtain shaped tofu. Finally, freeze the tofu in a refrigerator. After freezing, remove it and dry it in a drying oven for one day to obtain the silicon-based material coated on the frozen tofu.
[0105] (8) Grind the silicon-based material coating the frozen tofu into powder in an agate mortar, pass it through a 100-mesh sieve, put the ground material into a boat and place it in a tube furnace, and burn it at 900°C for 6 hours. Grind the burned material into powder and pass it through a 200-mesh sieve to obtain the frozen tofu material.
[0106] The specific capacity-voltage curve of the silicon-based anode material prepared in this embodiment is not significantly different from that in Example 7.
[0107] Although embodiments of the present invention have been described above, any modifications and substitutions made by those skilled in the art without departing from the principles and spirit of the present invention are within the scope of protection claimed by the present invention.
Claims
1. A method for modifying a silicon-based anode material, characterized in that... Modifying nano-silicon using a phosphorus-containing modifier and soybean as a carbon source is characterized by comprising the following steps: (1) Add ethanol to an aqueous solution of phosphorus-containing modifier, stir magnetically, then add nano-silicon, and disperse evenly to obtain a mixed solution; the phosphorus-containing modifier is hydroxyethylidene diphosphate, aminotrimethylene phosphonic acid or 2-phospho-1,2,4-tricarboxylic acid butane; (2) The mixed solution was evenly coated onto a glass plate with a scraper, dried and ground into a fine powder, and then sieved to obtain a phosphorus-containing binder-modified silicon-based material; (3) Weigh out soybeans and make soy milk; (4) Weigh out the phosphorus-containing binder-modified silicon-based material, conductive slurry, asphalt, carbon nanotubes, CTAB and hydroxyethylidene diphosphonic acid respectively and add them to a beaker. Perform ultrasonic and high-speed homogenization to obtain well dispersed materials. (5) Add the dispersed material to the soy milk, boil and cool it, then quickly add it to the lactone. After the reaction, sieve, filter and press to obtain the tofu-coated silicon-based material. Freeze in the refrigerator and dry for one day to obtain the frozen tofu-coated silicon-based material. (6) Grind the silicon-based material coated with frozen tofu into powder and sieve it. Sinter it in a tube furnace. Grind the sintered material into powder and sieve it to obtain frozen tofu modified silicon-based anode material.
2. The method for modifying a silicon-based anode material according to claim 1, characterized in that: In step (1), the mass percentage concentration of the phosphorus-containing modifier aqueous solution is 50-70%, and the mass ratio of nano-silicon, phosphorus-containing modifier and ethanol is 1:(0.04-0.045):(2.2-2.5).
3. The method for modifying a silicon-based anode material according to claim 1, characterized in that: In step (2), the drying temperature is 50-70℃ and the drying time is 10-15 hours. The powder is ground into fine powder in an agate mortar and passed through a 200-mesh sieve.
4. The method for modifying a silicon-based anode material according to claim 1, characterized in that: In step (3), the process of preparing soy milk is as follows: 15 g of soybeans are placed in a beaker and soaked in distilled water for 8 hours. After soaking, the soybeans are poured into a blender, 100 mL of distilled water is added, and the blender is blended for 3 minutes. The soybean residue on the machine wall is rinsed with distilled water. The process is repeated twice to obtain raw soy milk. The raw soy milk is then passed through a 100-mesh sieve and heated to boiling in an infrared heating furnace.
5. The method for modifying a silicon-based anode material according to claim 1, characterized in that: In step (4), the ratio of phosphorus-containing binder modified silicon-based material, conductive slurry, asphalt, carbon nanotubes, CTAB and HEDP is 10:1:1:1:1:1, and the high-speed homogenization speed is 5000 r / min.
6. The method for modifying a silicon-based anode material according to claim 1, characterized in that: In step (5), the lactone is gluconic acid. Lactone; boiling and cooling: heating while stirring for 30 minutes, cooling to 85-95℃; filtration: laying a layer of gauze on a 50-mesh sieve, pouring the mixture into the 50-mesh sieve, and compacting the filter residue to obtain the formed tofu coated with silicon-based material.
7. The method for modifying a silicon-based anode material according to claim 1, characterized in that: In step (6), the sample is passed through a 100-mesh sieve before sintering and through a 200-mesh sieve after sintering. The sintering temperature is 900℃ and the sintering time is 6 hours.
Citation Information
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