Solid ionic conductor aramid fiber composite diaphragm and preparation method thereof
By introducing raw materials such as zirconium oxide, yttrium oxide, and hafnium oxide into aramid composite separators to prepare composite nano-slurries, the problems of insufficient high-temperature resistance and mechanical properties of separators in existing technologies have been solved, and the improvement of high strength, fast ion transport, and battery safety has been achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-04
- Publication Date
- 2026-04-07
AI Technical Summary
The solid-state ionic conductor aramid composite separators prepared in the prior art have shortcomings in terms of high temperature resistance and mechanical properties, resulting in poor battery safety and electrochemical performance.
A composite nanocolloid was prepared using zirconium oxide, yttrium oxide, and hafnium oxide as raw materials. This composite nanocolloid was then mixed with a solid ion conductor nanosolution to form a composite nanoslurry. This slurry was then coated onto an aramid-based membrane to enhance the membrane's high-temperature resistance and mechanical strength. Furthermore, the ionic conductivity was improved by constructing Li+ migration channels using lithium lanthanum zirconium oxide nanoparticles.
The prepared solid-state ionic conductor aramid composite separator has excellent high-temperature resistance, high strength and toughness and fast ion transport capability, which improves the safety and electrochemical stability of the battery.
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Abstract
Description
Technical Field
[0001] This application relates to the technical field of battery materials, and in particular to a solid-state ionic conductor aramid composite separator and its preparation method. Background Technology
[0002] With the rapid development of the new energy industry, lithium-ion batteries have been widely used in electric vehicles, energy storage systems, and other fields due to their advantages such as high energy density and long cycle life. As a key component of lithium-ion batteries, the separator plays a crucial role in isolating the positive and negative electrodes, preventing short circuits, and allowing the free transport of lithium ions. Its performance directly affects the battery's safety, rate performance, and cycle life. In recent years, solid-state ion conductor and aramid composite separators have become a research hotspot due to their combination of the high strength and chemical corrosion resistance of aramid materials with the ion conductivity of solid electrolytes.
[0003] Currently, existing methods for preparing solid-state ionic conductor aramid composite membranes mainly include solution casting, electrospinning, and lamination. However, aramid composite membranes prepared by these methods still have significant drawbacks in practical applications: Firstly, its high-temperature resistance is insufficient. When the battery operating temperature is too high, the aramid matrix is prone to molecular chain disorientation, which leads to a sharp increase in the thermal shrinkage rate of the separator, which in turn causes a short circuit between the positive and negative electrodes, posing a serious safety hazard. Secondly, the mechanical properties are poor. Due to the poor interfacial compatibility between the solid electrolyte particles and the aramid matrix, the composite separator is prone to problems such as particle shedding and matrix cracking during stretching or puncture, making it difficult to meet the mechanical stress requirements during battery assembly and use.
[0004] Therefore, how to develop a solid-state ionic conductor aramid composite separator with excellent high temperature resistance, high toughness and efficient ion transport capability has become a technical problem that urgently needs to be solved to improve the safety and electrochemical performance of lithium-ion batteries. Summary of the Invention
[0005] To address the shortcomings of existing technologies, this application provides a solid-state ionic conductor aramid composite separator and its preparation method.
[0006] In a first aspect, this application provides a solid ion-conducting aramid composite separator, which adopts the following technical solution: A solid-state ionic conductor aramid composite membrane includes an aramid slurry and a base membrane. The aramid slurry is coated on both sides of the base membrane to form an aramid coating. The aramid slurry includes the following raw materials in parts by weight: 40-60 parts of aramid polymerization liquid, 15-25 parts of composite nano slurry, and 15-20 parts of solvent. The composite nano slurry includes the following raw materials in parts by weight: 5-7 parts of zirconium oxide, 1-5 parts of yttrium oxide, 0.5-3 parts of hafnium oxide, 0.1-1 parts of polyethylene glycol, 40-60 parts of ammonia, 2.5-10 parts of solid-state ionic conductor nano solution, and 0.05-0.3 parts of coupling agent.
[0007] By adopting the above technical solution, this application uses zirconium oxide, yttrium oxide, and hafnium oxide as raw materials to prepare a composite nanocolloid. The composite nanocolloid is mixed with a solid ion conductor nano solution under the action of a coupling agent to prepare a composite nano slurry. Thus, the prepared solid ion conductor aramid composite membrane has the characteristics of high temperature resistance, high strength and toughness, and fast ion transport.
[0008] This application uses zirconium oxide, yttrium oxide, and hafnium oxide as raw materials to prepare a composite nanocolloid. The prepared composite nanocolloid is dispersed in an aramid fiber network, which hinders the thermal motion of aramid molecular chains at high temperatures, reduces the thermal shrinkage rate of the separator, and increases the thermal decomposition temperature of the separator, giving the separator excellent high-temperature resistance and heat shrinkage resistance. The prepared composite nanocolloid dispersed in the aramid fiber network enhances the mechanical strength and puncture resistance of the separator. At the same time, the prepared composite nanocolloid can further shorten the battery activation time and improve the rate performance of the battery.
[0009] Preferably, the solid ionic conductor nanosolution is at least one of lithium lanthanum zirconium oxide nanosolution, lithium titanium aluminum phosphate nanosolution, and lithium lanthanum titanium oxide nanosolution.
[0010] More preferably, the solid ionic conductor nanosolution is a lithium lanthanum zirconium oxide nanosolution.
[0011] By employing the above technical solution, lithium lanthanum zirconium oxide nanoparticles are added to the lithium lanthanum zirconium oxide nanoparticle solution to construct Li using oxygen vacancy defects. + The migration channels effectively improve the ionic conductivity and electrochemical stability of the membrane.
[0012] Preferably, the lithium lanthanum zirconium oxide nanosolution comprises the following raw materials in parts by weight: 0.5-2 parts polyvinylpyrrolidone, 5-10 parts ethanol, 5-10 parts water, 5-10 parts lithium nitrate, 15-20 parts lanthanum nitrate hexahydrate, 0.7-1.5 parts aluminum nitrate nonahydrate, and 5-15 parts zirconium acetate.
[0013] By adopting the above technical solution, this application prepares a lithium lanthanum zirconium oxide nanosol using lithium nitrate, lanthanum nitrate hexahydrate, aluminum nitrate nonahydrate, and zirconium acetate as raw materials. The lithium lanthanum zirconium oxide nanoparticles in the lithium lanthanum zirconium oxide nanosol construct Li2O2 nanoparticles with oxygen vacancy defects. + The migration channels effectively improve the ionic conductivity of the separator, significantly enhancing its high-rate charge-discharge performance. Simultaneously, the high chemical inertness and wide voltage window of the lithium lanthanum zirconium oxide nanoparticles suppress lithium dendrite penetration, broaden the applicable battery voltage, and effectively increase the thermal decomposition temperature of the separator. Furthermore, polyvinylpyrrolidone in the lithium lanthanum zirconium oxide nanoparticle solution prevents the aggregation of these nanoparticles through steric hindrance, ensuring uniform dispersion in the ethanol-water medium and avoiding ion transport blockage. Ultimately, this results in a separator that combines fast ion transport, strong electrochemical stability, and uniform dispersion.
[0014] Preferably, the preparation method of the lithium lanthanum zirconium oxide nanosolution includes the following steps: Polyvinylpyrrolidone, ethanol, and water were mixed, and then lithium nitrate, lanthanum nitrate hexahydrate, and aluminum nitrate nonahydrate were added and mixed. Finally, zirconium acetate was added and mixed to obtain a lithium lanthanum zirconium oxide nanosol.
[0015] Preferably, the mixing time for lithium nitrate, lanthanum nitrate hexahydrate, and aluminum nitrate nonahydrate is 2-4 hours.
[0016] Preferably, the mixing time for adding zirconium acetate is 1-3 hours.
[0017] Preferably, the preparation method of the composite nano-slurry includes the following steps: Zirconia, yttrium oxide, and hafnium oxide were mixed, and then polyethylene glycol and ammonia were added and mixed again. The mixture was then filtered to obtain the final mixture. The mixture was combined with a solid ionic conductor nanosolution and a coupling agent to obtain a composite nanoslurry.
[0018] Preferably, the solvent includes at least one of dimethylacetamide, dimethylformamide, dimethyl sulfoxide, and acetone.
[0019] Preferably, the preparation method of the aramid polymer liquid includes the following steps: terephthaloyl chloride, p-phenylenediamine and a third monomer in a molar ratio of 10:(3-7):(3-7) are co-dispersed in a composite solvent and reacted to obtain the aramid polymer liquid; The third monomer comprises 4,4'-diaminodiphenyl ether and adipate diamine; the molar ratio of 4,4'-diaminodiphenyl ether and adipate diamine is (6-7):(3-4). The composite solvent includes a chlorinated (1-butyl-3-methylimidazolium) ionic liquid; the volume percentage of the chlorinated (1-butyl-3-methylimidazolium) ionic liquid is 13-18% of the total volume of the composite solvent.
[0020] Secondly, this application provides a method for preparing a solid ion-conducting aramid composite separator, which adopts the following technical solution: A method for preparing a solid-state ionic conductor aramid composite separator, comprising the following steps: Weigh out each ingredient according to the formula; Aramid polymer solution, composite nano-slurry, and solvent are mixed to obtain aramid slurry. Then, para-aramid slurry is coated on both sides of the base film. After coagulation, washing, and drying, para-aramid lithium battery separator is obtained.
[0021] In summary, this application includes at least one of the following beneficial technical effects: This application discloses a solid ion conductor aramid composite separator and its preparation method. By improving the raw materials of aramid slurry, the solid ion conductor aramid composite separator prepared in this application has good tensile strength and puncture strength. At the same time, the separator prepared in this application does not affect the discharge capacity of the battery and the cycle life of the battery is also guaranteed. The solid-state ionic conductor aramid composite separator prepared in this application has good high-temperature resistance, which reduces the thermal shrinkage of the separator at high temperatures and thus improves the electrochemical stability of lithium batteries. Detailed Implementation
[0022] The technical solutions of this application are further illustrated by specific embodiments below. These specific embodiments do not represent a limitation on the scope of protection of this application. Any non-essential modifications and adjustments made by others based on the concept of this application still fall within the scope of protection of this application.
[0023] All raw materials involved in this application are commercially available products, among which, Polyvinyl alcohol methylpyrrolidone, M n =1,300,000, purchased from Aladdin Reagent Co., Ltd.; Ethanol, AR, ≥99.7%, purchased from Aladdin Reagent Co., Ltd. Lithium nitrate, AR, 99.99%, purchased from Aladdin Reagent Co., Ltd. Lanthanum nitrate hexahydrate, AR, 99.99%, purchased from Aladdin Reagent Co., Ltd. Aluminum nitrate nonahydrate, AR, 99.99%, purchased from Aladdin Reagent Co., Ltd. Zirconium acetate, Zr, 15%-16%, purchased from Aladdin Reagent Co., Ltd. Zirconia, purity ≥99.99%, purchased from Aladdin Reagent Co., Ltd. Yttrium oxide, purity ≥99.99%, purchased from Aladdin Reagent Co., Ltd. Hafnium oxide, purity ≥ 99.99%, purchased from Aladdin Reagent Co., Ltd. Polyethylene glycol, with an average molecular weight of approximately 4000, CAS number: 25322-68-3, was purchased from Aladdin Reagent Co., Ltd. The present application will be further described in detail below with reference to embodiments and comparative examples.
[0024] Preparation Example 1: The preparation method of lithium lanthanum zirconium oxide nanoparticle solution is as follows: 1.5g of polyvinylpyrrolidone, 7g of ethanol, and 7g of water were mixed for 1 hour. Then, 8g of lithium nitrate, 17g of lanthanum nitrate hexahydrate, and 1.1g of aluminum nitrate nonahydrate were added and mixed for 2 hours. Finally, 10g of zirconium acetate and 20g of water were added and mixed for 1 hour to obtain a lithium lanthanum zirconium oxide nanosol.
[0025] Preparation Example 2: The preparation method of lithium lanthanum zirconium oxide nanoparticle solution is as follows: Mix 0.5g of polyvinylpyrrolidone, 5g of ethanol, and 5g of water for 1 hour. Then add 5g of lithium nitrate, 15g of lanthanum nitrate hexahydrate, and 0.7g of aluminum nitrate nonahydrate and mix for 2 hours. Finally, add 5g of zirconium acetate and 20g of water and mix for 1 hour to obtain a lithium lanthanum zirconium oxide nanosol.
[0026] Preparation Example 3: The preparation method of lithium lanthanum zirconium oxide nanoparticle solution is as follows: 2g of polyvinylpyrrolidone, 10g of ethanol, and 10g of water were mixed for 1 hour. Then, 10g of lithium nitrate, 20g of lanthanum nitrate hexahydrate, and 1.5g of aluminum nitrate nonahydrate were added and mixed for 2 hours. Finally, 15g of zirconium acetate and 20g of water were added and mixed for 1 hour to obtain a lithium lanthanum zirconium oxide nanosol.
[0027] Preparation Example 4: The preparation method of the composite nano-slurry includes the following steps: 6g of zirconium oxide, 1.2g of yttrium oxide, 1.2g of hafnium oxide, and deionized water were mixed to obtain a first mixed solution with a total metal ion concentration of 0.1mol / L. 0.5g of polyethylene glycol and 50g of ammonia were mixed to obtain a second mixed solution; The first solution was added dropwise to the second mixed solution at a rate of 20 mL / min while stirring with a mechanical stirrer. After the addition was complete, the mixture was washed with distilled water until no AgCl precipitate was observed when tested with AgNO3. The washed colloid was then vacuum filtered to obtain a colloidal filter cake. The colloidal filter cake was mixed with 7g of lithium lanthanum zirconium oxide nanosol, 0.15g of coupling agent KH550, and 50mL of water to obtain a composite nanoslurry.
[0028] The lithium lanthanum zirconium oxide nanosolution was obtained from Preparation Example 1.
[0029] Preparation Example 5: The preparation method of the composite nano-slurry includes the following steps: 5g of zirconium oxide, 1g of yttrium oxide, 0.5g of hafnium oxide, and deionized water were mixed to obtain a first mixed solution with a total metal ion concentration of 0.1mol / L. 0.1g of polyethylene glycol and 40g of ammonia were mixed to obtain a second mixed solution; The first solution was added dropwise to the second mixed solution at a rate of 20 mL / min while stirring with a mechanical stirrer. After the addition was complete, the mixture was washed with distilled water until no AgCl precipitate was observed when tested with AgNO3. The washed colloid was then vacuum filtered to obtain a colloidal filter cake. The colloidal filter cake was mixed with 2.5g of lithium lanthanum zirconium oxide nano solution, 0.05g of coupling agent KH550, and 50mL of water to obtain a composite nano slurry.
[0030] The lithium lanthanum zirconium oxide nanosolution was obtained from Preparation Example 2.
[0031] Preparation Example 6: The preparation method of the composite nano-slurry includes the following steps: 7g of zirconium oxide, 5g of yttrium oxide, 3g of hafnium oxide, and deionized water were mixed to obtain a first mixed solution with a total metal ion concentration of 0.1mol / L. 1g of polyethylene glycol and 60g of ammonia were mixed to obtain a second mixed solution; The first solution was added dropwise to the second mixed solution at a rate of 20 mL / min while stirring with a mechanical stirrer. After the addition was complete, the mixture was washed with distilled water until no AgCl precipitate was observed when tested with AgNO3. The washed colloid was then vacuum filtered to obtain a colloidal filter cake. The colloidal filter cake was mixed with 10g of lithium lanthanum zirconium oxide nanosolution, 0.3g of coupling agent KH550, and 50mL of water to obtain a composite nanoslurry.
[0032] The lithium lanthanum zirconium oxide nanosolution was obtained from Preparation Example 3.
[0033] Example 1:
[0034] A method for preparing a solid-state ionic conductor aramid composite separator includes the following steps: S1. Preparation of aramid polymerization solution: Under nitrogen protection, 1-butyl-3-methylimidazolium chloride ionic liquid and DMAC were mixed at a volume ratio of 13:87 and stirred until homogeneous to obtain a composite solvent. Then, 7 mol of the third monomer (6 mol of 4,4'-diaminodiphenyl ether and 1 mol of adipate diamine) was added to the composite solvent and completely dissolved. Then, 3 mol of p-phenylenediamine was added and stirred until completely dissolved. The mixture was then cooled to -10°C. Finally, 10 mol of terephthaloyl chloride was added in three portions and stirred at 1000 r / min. When the viscosity of the system increased sharply, the cooling was stopped and the reaction was allowed to continue at room temperature for 2 h. Finally, calcium hydroxide was added to adjust the pH of the system to 7. After degassing with a vacuum pump, the aramid polymer solution was obtained.
[0035] S2. Preparation of aramid slurry: Mix 50g of aramid polymerization liquid and 20g of composite nano slurry, stir at 600r / min for 40min, then add 18g of dimethylformamide and stir at 500r / min for 50min to adjust the viscosity of the system to 2000mPa·s. Filter through a 350-mesh screen to obtain aramid slurry. The composite nano-slurry was prepared in Preparation Example 4.
[0036] S3. Preparation of battery separator: The aramid slurry was evenly coated onto both sides of the base film using a coating machine. The film was then cured in a coagulation bath using an immersion reverse rotation method, washed with deionized water, and dried to obtain a solid ion conductor aramid composite membrane.
[0037] Example 2:
[0038] A method for preparing a solid-state ionic conductor aramid composite separator includes the following steps: S1. Preparation of aramid polymerization solution: Under nitrogen protection, 1-butyl-3-methylimidazolium chloride ionic liquid and DMAC were mixed at a volume ratio of 13:87 and stirred until homogeneous to obtain a composite solvent. Then, 7 mol of the third monomer (6 mol of 4,4'-diaminodiphenyl ether and 1 mol of adipate diamine) was added to the composite solvent and completely dissolved. Then, 3 mol of p-phenylenediamine was added and stirred until completely dissolved. The mixture was then cooled to -10°C. Finally, 10 mol of terephthaloyl chloride was added in three portions and stirred at 1000 r / min. When the viscosity of the system increased sharply, the cooling was stopped and the reaction was allowed to continue at room temperature for 2 h. Finally, calcium hydroxide was added to adjust the pH of the system to 7. After degassing with a vacuum pump, the aramid polymer solution was obtained.
[0039] S2. Preparation of aramid slurry: 40g of aramid polymerization liquid and 15g of composite nano slurry were mixed and stirred at 600r / min for 40min. Then, 15g of dimethylformamide was added and stirred at 500r / min for 50min to adjust the viscosity of the system to 2000mPa·s. The mixture was then passed through a 350-mesh filter to obtain the aramid slurry. The composite nano-slurry was prepared in Preparation Example 5.
[0040] S3. Preparation of battery separator: The aramid slurry was evenly coated onto both sides of the base film using a coating machine. The film was then cured in a coagulation bath using an immersion reverse rotation method, washed with deionized water, and dried to obtain a solid ion conductor aramid composite membrane.
[0041] Example 3:
[0042] A method for preparing a solid-state ionic conductor aramid composite separator includes the following steps: S1. Preparation of aramid polymerization solution: Under nitrogen protection, 1-butyl-3-methylimidazolium chloride ionic liquid and DMAC were mixed at a volume ratio of 13:87 and stirred until homogeneous to obtain a composite solvent. Then, 7 mol of the third monomer (6 mol of 4,4'-diaminodiphenyl ether and 1 mol of adipate diamine) was added to the composite solvent and completely dissolved. Then, 3 mol of p-phenylenediamine was added and stirred until completely dissolved. The mixture was then cooled to -10°C. Finally, 10 mol of terephthaloyl chloride was added in three portions and stirred at 1000 r / min. When the viscosity of the system increased sharply, the cooling was stopped and the reaction was allowed to continue at room temperature for 2 h. Finally, calcium hydroxide was added to adjust the pH of the system to 7. After degassing with a vacuum pump, the aramid polymer solution was obtained.
[0043] S2. Preparation of aramid slurry: Mix 60g of aramid polymerization liquid and 25g of composite nano slurry, stir at 600r / min for 40min, then add 20g of dimethylformamide and stir at 500r / min for 50min to adjust the viscosity of the system to 2000mPa·s. Filter through a 350-mesh screen to obtain aramid slurry. The composite nano-slurry was prepared in Preparation Example 6.
[0044] S3. Preparation of battery separator: The aramid slurry was evenly coated onto both sides of the base film using a coating machine. The film was then cured in a coagulation bath using an immersion reverse rotation method, washed with deionized water, and dried to obtain a solid ion conductor aramid composite membrane.
[0045] Example 4:
[0046] The difference from Example 1 is that the amount of composite nano-slurry added is different when preparing aramid slurry.
[0047] In this embodiment, the amount of composite nano-slurry added is 15g.
[0048] Example 5:
[0049] The difference from Example 1 is that the amount of composite nano-slurry added is different when preparing aramid slurry.
[0050] In this embodiment, the amount of composite nano-slurry added is 25g.
[0051] Example 6:
[0052] A method for preparing a solid-state ionic conductor aramid composite separator includes the following steps: S1. Preparation of aramid polymerization solution: Under nitrogen protection, 1-butyl-3-methylimidazolium chloride ionic liquid and DMAC were mixed at a volume ratio of 13:87 and stirred until homogeneous to obtain a composite solvent. Then, 7 mol of the third monomer (6 mol of 4,4'-diaminodiphenyl ether and 1 mol of adipate diamine) was added to the composite solvent and completely dissolved. Then, 3 mol of p-phenylenediamine was added and stirred until completely dissolved. The mixture was then cooled to -10°C. Finally, 10 mol of terephthaloyl chloride was added in three portions and stirred at 1000 r / min. When the viscosity of the system increased sharply, the cooling was stopped and the reaction was allowed to continue at room temperature for 2 h. Finally, calcium hydroxide was added to adjust the pH of the system to 7. After degassing with a vacuum pump, the aramid polymer solution was obtained.
[0053] S2. Preparation of aramid slurry: Mix 50g of aramid polymerization liquid and 20g of composite nano slurry, stir at 600r / min for 40min, then add 18g of dimethylformamide and stir at 500r / min for 50min to adjust the viscosity of the system to 2000mPa·s. Filter through a 350-mesh screen to obtain aramid slurry. The composite nano-slurry was prepared in Preparation Example 5.
[0054] S3. Preparation of battery separator: The aramid slurry was evenly coated onto both sides of the base film using a coating machine. The film was then cured in a coagulation bath using an immersion reverse rotation method, washed with deionized water, and dried to obtain a solid ion conductor aramid composite membrane.
[0055] Example 7:
[0056] A method for preparing a solid-state ionic conductor aramid composite separator includes the following steps: S1. Preparation of aramid polymerization solution: Under nitrogen protection, 1-butyl-3-methylimidazolium chloride ionic liquid and DMAC were mixed at a volume ratio of 13:87 and stirred until homogeneous to obtain a composite solvent. Then, 7 mol of the third monomer (6 mol of 4,4'-diaminodiphenyl ether and 1 mol of adipate diamine) was added to the composite solvent and completely dissolved. Then, 3 mol of p-phenylenediamine was added and stirred until completely dissolved. The mixture was then cooled to -10°C. Finally, 10 mol of terephthaloyl chloride was added in three portions and stirred at 1000 r / min. When the viscosity of the system increased sharply, the cooling was stopped and the reaction was allowed to continue at room temperature for 2 h. Finally, calcium hydroxide was added to adjust the pH of the system to 7. After degassing with a vacuum pump, the aramid polymer solution was obtained.
[0057] S2. Preparation of aramid slurry: Mix 50g of aramid polymerization liquid and 20g of composite nano slurry, stir at 600r / min for 40min, then add 18g of dimethylformamide and stir at 500r / min for 50min to adjust the viscosity of the system to 2000mPa·s. Filter through a 350-mesh screen to obtain aramid slurry. The composite nano-slurry was prepared in Preparation Example 6.
[0058] S3. Preparation of battery separator: The aramid slurry was evenly coated onto both sides of the base film using a coating machine. The film was then cured in a coagulation bath using an immersion reverse rotation method, washed with deionized water, and dried to obtain a solid ion conductor aramid composite membrane.
[0059] Comparative Example 1: The difference from Example 1 is that no composite nano-slurry is added when preparing the aramid slurry.
[0060] Comparative Example 2: The difference from Example 1 is that the amount of composite nano-slurry added is different when preparing aramid slurry.
[0061] In this embodiment, the amount of composite nano-slurry added is 14g.
[0062] Comparative Example 3: The difference from Example 1 is that the amount of composite nano-slurry added is different when preparing aramid slurry.
[0063] In this embodiment, the amount of composite nano-slurry added is 26g.
[0064] Comparative Example 4: The difference from Example 1 is that the composite nanoslurry is replaced with an equal weight of lithium lanthanum zirconium oxide nanosolution prepared by the following method.
[0065] The preparation steps of lithium lanthanum zirconium oxide nanoparticle solution are as follows: 1.5g of polyvinylpyrrolidone, 7g of ethanol, and 7g of water were mixed for 1 hour. Then, 8g of lithium nitrate, 17g of lanthanum nitrate hexahydrate, and 1.1g of aluminum nitrate nonahydrate were added and mixed for 2 hours. Finally, 10g of zirconium acetate and 20g of water were added and mixed for 1 hour to obtain a lithium lanthanum zirconium oxide nanosol.
[0066] Performance testing: 1. Tensile strength: Tensile strength was tested according to the method specified in GB / 13022-91 "Test Method for Tensile Properties of Plastic Films".
[0067] 2. Puncture intensity: The puncture strength was tested according to the method specified in GB / T21302-2007 "General Rules for Composite Films and Bags for Packaging".
[0068] 3. Discharge capacity: The separators obtained in the examples and comparative examples were assembled into CR2032 button batteries in the order of positive electrode active material, electrolyte, separator, and lithium sheet. The batteries were then pressed together using a battery packaging machine and left to stand for more than 12 hours until the batteries were fully balanced. The discharge capacity of the samples was then tested on a battery testing system to test the discharge capacity at 3C.
[0069] 4. Battery capacity retention rate: The separators obtained in the examples and comparative examples were assembled into CR2032 button batteries in the order of positive electrode active material, electrolyte, separator, and lithium sheet. The batteries were then pressed together using a battery packaging machine and left to stand for more than 12 hours until the batteries were fully balanced. After that, charge-discharge cycle tests were performed on a battery testing system with a constant current rate of 1C and a charge-discharge cutoff voltage of 2.5-3.8V. The battery capacity retention rate was recorded after 100 cycles.
[0070] Table 1 Performance Test Results
[0071] As shown in Table 1, the solid-state ionic conductor aramid composite separators prepared in Examples 1-7 of this application have good tensile strength and puncture strength. At the same time, the separators prepared in this application do not affect the discharge capacity of the battery, and the cycle life of the battery is also guaranteed.
[0072] Based on the test results of Example 1 and Comparative Example 1, it can be seen that the tensile strength and puncture strength of the solid ion conductor aramid composite separator prepared in Example 1 are better than those of Comparative Example 1. This indicates that the addition of composite nano-slurry during the preparation of aramid slurry in this application effectively improves the tensile strength and puncture strength of the solid ion conductor aramid composite separator. At the same time, the separator prepared in this application does not affect the discharge capacity of the battery, and the cycle life of the battery is also guaranteed.
[0073] Based on the test results of Examples 1, 4, 5, Comparative Examples 2 and 3, it can be seen that the amount of composite nano-slurry added during the preparation of aramid slurry in this application has a certain influence on the tensile strength and puncture strength of the solid ion conductor aramid composite separator. Furthermore, the tensile strength and puncture strength of the solid ion conductor aramid composite separator are optimal when the amount of composite nano-slurry added is 15-25 parts by mass. At the same time, the separator prepared in this application does not affect the discharge capacity of the battery, and the cycle life of the battery is also guaranteed.
[0074] Based on the test results of Example 1 and Comparative Example 4, it can be seen that when the composite nano-slurry is replaced with an equal weight of lithium lanthanum zirconium oxide nano-solution, the tensile strength and puncture strength of the separator decrease. This indicates that the solid ionic conductor aramid composite separator prepared by this application using composite nano-slurry as raw material has good tensile strength and puncture strength. At the same time, the separator prepared by this application does not affect the discharge capacity of the battery, and the cycle life of the battery is also guaranteed.
[0075] 5. Heat shrinkage: Heat shrinkage was tested according to the method specified in GB / T12027-2004 "Test Method for Dimensional Change Rate of Plastic Films and Sheets under Heat".
[0076] Table 2 Results of heat shrinkage rate test
[0077] In Table 2, MD represents the vertical direction and TD represents the horizontal direction.
[0078] As shown in Table 1, the solid-state ionic conductor aramid composite separators prepared in Examples 1-7 of this application have good thermal stability and high temperature resistance, reducing the thermal shrinkage of the separator at high temperatures, thereby improving the electrochemical stability of lithium batteries.
[0079] Based on the test results of Example 1 and Comparative Example 1, it can be seen that the solid ion conductor aramid composite separator prepared in Example 1 has better heat shrinkage resistance than that of Comparative Example 1. This indicates that the addition of composite nano-slurry during the preparation of aramid slurry in this application effectively improves the thermal stability and high temperature resistance of the solid ion conductor aramid composite separator, reduces the phenomenon of separator heat shrinkage at high temperatures, and thus improves the electrochemical stability of lithium battery.
[0080] Based on the test results of Examples 1, 4, 5, Comparative Examples 2 and 3, it can be seen that the amount of composite nano-slurry added during the preparation of aramid slurry in this application has a certain influence on the heat shrinkage resistance of the solid ion conductor aramid composite membrane. Furthermore, the heat shrinkage resistance of the solid ion conductor aramid composite membrane is optimal when the amount of composite nano-slurry added is 15-25 parts by mass.
[0081] Based on the test results of Example 1 and Comparative Example 4, it can be seen that when the composite nano-slurry is replaced with an equal weight of lithium lanthanum zirconium oxide nano-solution, the thermal shrinkage resistance of the separator decreases. This indicates that the solid ionic conductor aramid composite separator prepared by this application using composite nano-slurry as raw material has good thermal stability and high temperature resistance, reduces the phenomenon of separator thermal shrinkage at high temperatures, and thus improves the electrochemical stability of lithium battery.
Claims
1. A solid-state ionic conductor aramid composite separator, characterized in that: The product includes an aramid slurry and a base film. The aramid slurry is coated on both sides of the base film to form an aramid coating. The aramid slurry includes the following raw materials in parts by weight: 40-60 parts of aramid polymerization liquid, 15-25 parts of composite nano slurry, and 15-20 parts of solvent. The composite nano-slurry comprises the following raw materials in parts by weight: 5-7 parts zirconium oxide, 1-5 parts yttrium oxide, 0.5-3 parts hafnium oxide, 0.1-1 parts polyethylene glycol, 40-60 parts ammonia, 2.5-10 parts solid ion conductor nano solution, and 0.05-0.3 parts coupling agent.
2. The solid-state ionic conductor aramid composite separator according to claim 1, characterized in that: The solid ionic conductor nanosolution is at least one of lithium lanthanum zirconium oxide nanosolution, lithium titanium aluminum phosphate nanosolution, and lithium lanthanum titanium oxide nanosolution.
3. The solid-state ionic conductor aramid composite separator according to claim 2, characterized in that: The lithium lanthanum zirconium oxide nanosolution comprises the following raw materials in parts by weight: 0.5-2 parts polyvinylpyrrolidone, 5-10 parts ethanol, 5-10 parts water, 5-10 parts lithium nitrate, 15-20 parts lanthanum nitrate hexahydrate, 0.7-1.5 parts aluminum nitrate nonahydrate, and 5-15 parts zirconium acetate.
4. The solid-state ionic conductor aramid composite separator according to claim 3, characterized in that: The preparation method of the lithium lanthanum zirconium oxide nanosolution includes the following steps: mixing polyvinylpyrrolidone, ethanol, and water; adding lithium nitrate, lanthanum nitrate hexahydrate, and aluminum nitrate nonahydrate and mixing; and then adding zirconium acetate and mixing to obtain the lithium lanthanum zirconium oxide nanosolution.
5. The solid-state ionic conductor aramid composite separator according to claim 4, characterized in that: The mixing time for adding lithium nitrate, lanthanum nitrate hexahydrate, and aluminum nitrate nonahydrate is 2-4 hours.
6. The solid-state ionic conductor aramid composite separator according to claim 4, characterized in that: The mixing time for adding zirconium acetate is 1-3 hours.
7. The solid-state ionic conductor aramid composite separator according to claim 1, characterized in that: The preparation method of the composite nano-slurry includes the following steps: Zirconia, yttrium oxide, and hafnium oxide were mixed, and then polyethylene glycol and ammonia were added and mixed again. The mixture was then filtered to obtain the final mixture. The mixture was combined with a solid ionic conductor nanosolution and a coupling agent to obtain a composite nanoslurry.
8. The solid-state ionic conductor aramid composite separator according to claim 1, characterized in that: The solvent includes at least one of dimethylacetamide, dimethylformamide, dimethyl sulfoxide, and acetone.
9. The solid-state ionic conductor aramid composite separator according to claim 1, characterized in that: The preparation method of the aramid polymer liquid is as follows: terephthaloyl chloride, p-phenylenediamine and a third monomer in a molar ratio of 10:(3-7):(3-7) are co-dispersed in a composite solvent and reacted to obtain the aramid polymer liquid; The third monomer comprises 4,4'-diaminodiphenyl ether and adipate diamine; the molar ratio of 4,4'-diaminodiphenyl ether and adipate diamine is (6-7):(3-4). The composite solvent includes a chlorinated (1-butyl-3-methylimidazolium) ionic liquid; the volume percentage of the chlorinated (1-butyl-3-methylimidazolium) ionic liquid is 13-18% of the total volume of the composite solvent.
10. A method for preparing a solid-state ionic conductor aramid composite separator, characterized in that: The preparation method steps are as follows: Weigh out each ingredient according to the formula; Aramid polymer solution, composite nano-slurry, and solvent are mixed to obtain aramid slurry. Then, para-aramid slurry is coated on both sides of the base film. After coagulation, washing, and drying, para-aramid lithium battery separator is obtained.