A photocured composite solid electrolyte separator and a method for preparing the same
By coating a polyolefin-based film with a composite coating of modified solid electrolyte, photoinitiator, and crosslinking agent, a three-dimensional network structure is formed, which solves the problems of lithium dendrite puncture and thermal shrinkage, and improves the safety and ion conduction performance of lithium batteries.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HEBEI GELLEC NEW ENERGY MATERIAL SCI&TECHNOLOY CO LTD
- Filing Date
- 2026-04-01
- Publication Date
- 2026-06-09
AI Technical Summary
Existing polyolefin-based films are difficult to effectively block lithium dendrite penetration and are prone to irreversible thermal shrinkage at high temperatures, leading to battery short circuits. Furthermore, ceramic coatings cannot simultaneously achieve high ion conductivity.
A composite coating consisting of modified solid electrolyte, photoinitiator, crosslinking agent and pore-forming agent is used to form a three-dimensional network structure through photocuring, which improves the heat resistance and ionic conductivity of the diaphragm and retains the pore structure.
The heat resistance, ion transport performance and interface stability of the separator have been comprehensively optimized, which improves the safety and service life of lithium batteries.
Smart Images
Figure CN122178058A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of battery separator technology, specifically relating to a photocurable composite solid electrolyte separator and its preparation method. Background Technology
[0002] As a core component of lithium-ion batteries, the separator directly affects the battery's safety performance, cycle life, and rate performance. Currently, commercially available separators are mainly made of polyolefin materials such as polyethylene and polypropylene. While these polyolefin-based membranes possess excellent mechanical strength and electrochemical stability, they are unable to effectively prevent lithium dendrite penetration and are prone to irreversible thermal shrinkage at high temperatures, leading to battery short circuits and severely shortening battery life. To address this technical problem, existing technologies generally coat the surface of the polyolefin-based membrane with a slurry to form a ceramic coating, resulting in a ceramic-coated separator. Although this method improves thermal stability compared to polyolefin-based membranes, it cannot simultaneously maintain high ion conductivity. Therefore, the development of novel composite separators has significant practical implications and application value. Summary of the Invention
[0003] In view of the shortcomings of the prior art, the purpose of this invention is to provide a photocurable composite solid electrolyte membrane.
[0004] Another object of the present invention is to provide a method for preparing the above-mentioned photocurable composite solid electrolyte membrane.
[0005] The objective of this invention is achieved through the following technical solution.
[0006] A photocurable composite solid electrolyte membrane includes: a base membrane and a coating on the base membrane, wherein the coating is obtained by coating with a slurry, and the raw materials for preparing the slurry include: a modified solid electrolyte, a photoinitiator, a crosslinking agent, and a pore-forming agent. The modified solid electrolyte is a solid electrolyte treated with an inorganic nanoparticle precursor, wherein the inorganic nanoparticle precursor is one or a mixture of aluminum isopropoxide, barium nitrate, tetrabutyl titanate, tetraethyl orthosilicate, tetrabutyl zirconate, and zinc acetate. By mass parts, the ratio of photoinitiator, crosslinking agent, modified solid electrolyte, and pore-forming agent is (0.1~3):(20~40):(30~60):(10~20).
[0007] In the above technical solution, the photoinitiator is one or a mixture of α-hydroxyacetophenone photoinitiators, α-aminoacetophenone photoinitiators, acylphosphine oxide photoinitiators, coumarin photoinitiators, benzophenone photoinitiators, thioxanthone photoinitiators, anthraquinone photoinitiators, and α-diketone photoinitiators.
[0008] In the above technical solution, the crosslinking agent is a multifunctional acrylate, which is one or a mixture of polyurethane acrylate, dipentaerythritol hexaacrylate, trimethylolpropane triacrylate and hexanediol diacrylate.
[0009] In the above technical solution, the pore-forming agent is at least one of methanol, ethanol, acetone, dichloromethane, ethyl acetate and isopropanol.
[0010] In the above technical solution, the method for preparing the modified solid electrolyte includes: mixing a solution containing solid electrolyte and an inorganic nanoparticle precursor until homogeneous, adjusting the pH to 8-11, stirring and reacting at 50-80℃ for 1-2 hours, centrifuging, washing, drying, and calcining at 400-700℃ for 2 hours to obtain the modified solid electrolyte, wherein, by mass fraction, the ratio of the inorganic nanoparticle precursor to the solid electrolyte in the solution containing solid electrolyte is 1:(2-5).
[0011] In the above technical solution, the method for obtaining a solution containing solid electrolyte includes: mixing solid electrolyte (powder) and solvent until homogeneous to obtain a solution containing solid electrolyte, wherein the content of solid electrolyte in the solution is 20~30wt%.
[0012] In the above technical solution, the solvent is a mixture of water and anhydrous ethanol, and the ratio of water to anhydrous ethanol by volume is (1~3):(3~5).
[0013] In the above technical solution, the solid electrolyte is one or a mixture of lithium lanthanum zirconium oxide (LLZO), tantalum-doped lithium lanthanum zirconium oxide (LLZTO), lithium lanthanum titanium oxide (LLTO), lithium titanium aluminum phosphate (LATP), and lithium germanium aluminum phosphate (LAGP).
[0014] In the above technical solution, the inorganic nanoparticle precursor is preferably a mixture of aluminum isopropoxide and tetrabutyl zirconate.
[0015] In the above technical solution, the crosslinking agent is preferably a mixture of dipentaerythritol hexaacrylate and trimethylolpropane triacrylate.
[0016] The above-mentioned method for preparing a photocurable composite solid electrolyte membrane includes: coating a slurry onto at least one side of a base membrane, irradiating it with light, drying it, forming a coating on the base membrane, and obtaining a photocurable composite solid electrolyte membrane.
[0017] In the above technical solution, the illumination time is 1~2 minutes, and the light source is a low-pressure mercury lamp or an LED lamp.
[0018] In the above technical solution, the wavelength of the LED light is 365~465nm.
[0019] A method for preparing a slurry includes: mixing a photoinitiator, a crosslinking agent, a modified solid electrolyte, and a pore-forming agent until homogeneous to obtain a slurry, wherein the ratio of the photoinitiator, crosslinking agent, modified solid electrolyte, and pore-forming agent by mass parts is (0.1~3):(20~40):(30~60):(10~20).
[0020] In the above technical solution, the photoinitiator and crosslinking agent are mixed and stirred until uniform, then the modified solid electrolyte is added and sonicated until uniform, and finally the pore-forming agent is added and stirred until uniform to obtain the slurry.
[0021] Application of modified solid electrolytes, photoinitiators, crosslinking agents and pore-forming agents to synergistically improve the heat resistance and ionic conductivity of membranes.
[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0023] Photoinitiators can trigger cross-linking reactions between the molecular chains inside the separator and the cross-linking agent under light irradiation, forming a three-dimensional network structure, which greatly improves the heat resistance of the separator. Modified solid electrolytes can simultaneously improve the ionic conductivity and heat resistance of the separator, and effectively improve the problem of poor interfacial compatibility of solid electrolytes. At the same time, the pore-forming agent volatilizes during drying, which can accurately preserve the pore structure of the separator and avoid the problem of decreased ionic conductivity due to pore blockage. Ultimately, the heat resistance, ion transport performance and interfacial stability of lithium battery separators are comprehensively optimized. Attached Figure Description
[0024] Figure 1 SEM image of the diaphragm prepared from the slurry of Example 7. Detailed Implementation
[0025] The technical solution of the present invention will be further described below with reference to specific embodiments.
[0026] Tetrabutyl zirconate: CAS: 1071-76-7.
[0027] Aluminum isopropoxide: CAS: 555-31-7.
[0028] Lithium lanthanum zirconium oxide (LLZO): Purchased from Shanghai Maclean Biochemical Technology Co., Ltd. Garnet-type solid electrolyte, average particle size 5 μm.
[0029] Camphorquinone: CAS: 10373-78-1.
[0030] Trimethylolpropane triacrylate: CAS: 15625-89-5.
[0031] Dipentaerythritol hexaacrylate: CAS: 29570-58-9.
[0032] Benzophenone: CAS: 119-61-9.
[0033] In the following examples and comparative examples, the water used is deionized water.
[0034] In the following examples and comparative examples, the base film is a polyethylene film with a thickness of 7 μm.
[0035] 150℃ heat shrinkage test: The transverse (TD) heat shrinkage rate and longitudinal (MD) heat shrinkage rate were determined according to the test method in GB / T 36363-2018 "Polyolefin separator for lithium-ion batteries". The separator was cut into a size of 60 mm in length and 40 mm in width as a sample. Three parallel samples were prepared for each example. The test results of the transverse heat shrinkage rate and longitudinal heat shrinkage rate of the example were the average value of the three samples.
[0036] Membrane rupture temperature: The diaphragm was cut into samples with a length of 8 mm and a width of 4.5 mm. The samples were tested using a thermomechanical analyzer (TA's TMA Q400). The tensile force was 0.03 N and the heating rate was 5 °C / min.
[0037] The ionic conductivity of the separator was tested according to GB / T 36363-2018 "Polyolefin separators for lithium-ion batteries".
[0038] Interfacial impedance: In a glove box, using lithium sheets as the working and counter electrodes, the working electrode, separator, and counter electrode are sequentially stacked and wound into a battery core. Electrolyte is injected, and after encapsulation and activation, a lithium-ion symmetric battery is fabricated. EIS testing of the lithium-ion symmetric battery is performed on an electrochemical workstation. The frequency range of the EIS test is 10 Hz. 5 -10 -4 The frequency is Hz, and the amplitude is 5-10mV. The electrolyte is a mixture of electrolyte and solvent. The electrolyte is lithium hexafluorophosphate, and the solvent is a mixture of ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC) (the volume ratio of EC, EMC, and DMC is 1:1:1). The concentration of the electrolyte in the electrolyte is 1M.
[0039] Examples 1-4
[0040] A method for preparing a slurry includes: mixing a photoinitiator and a crosslinking agent, stirring at 100 r / min for 10 min until homogeneous, adding a modified solid electrolyte, sonicating at 40 kHz for 20 min until homogeneous, and finally adding a pore-forming agent, stirring at 100 r / min for 10 min until homogeneous to obtain a slurry. The ratio of photoinitiator, crosslinking agent, modified solid electrolyte, and pore-forming agent by mass is X, wherein the photoinitiator is camphorquinone (an α-diketone photoinitiator), the crosslinking agent is Y, and the pore-forming agent is ethanol; X and Y are shown in Table 1.
[0041] The modified solid electrolyte used in Examples 1-4 is the same. The method for preparing the modified solid electrolyte includes: mixing the solid electrolyte (powder) and solvent, sonicating at a frequency of 40 kHz for 30 min until homogeneous, to obtain a solution containing the solid electrolyte (the content of the solid electrolyte in the solution is 30 wt%), mixing the solution containing the solid electrolyte with an inorganic nanoparticle precursor, stirring at a speed of 80 r / min for 10 min until homogeneous, adding ammonia water (the concentration of NH3 in the ammonia water is 10 wt%) to adjust the pH to 9, and stirring at 70 °C. After reacting for 2 hours, a solid powder was obtained by centrifugation. The solid powder was washed three times with anhydrous ethanol, dried under vacuum at 80°C for 12 hours, and calcined at 400°C for 2 hours to obtain a modified solid electrolyte (LLZO@ZrO2). The ratio of the inorganic nanoparticle precursor to the solid electrolyte in the solution was 1:3 by mass. The solvent was a mixture of water and anhydrous ethanol. The ratio of water to anhydrous ethanol in the solvent was 1:3 by volume. The inorganic nanoparticle precursor was tetrabutyl zirconate, and the solid electrolyte was lithium lanthanum zirconium oxide (LLZO).
[0042] Table 1
[0043]
[0044] Example 5
[0045] A method for preparing the slurry is basically the same as in Example 1, except that "camphorquinone" is replaced with "benzophenone". Benzophenone belongs to the benzophenone class of photoinitiators.
[0046] Example 6
[0047] A method for preparing a slurry includes: mixing a photoinitiator and a crosslinking agent, stirring at 100 r / min for 10 min until homogeneous, adding a modified solid electrolyte, sonicating at 40 kHz for 20 min until homogeneous, and finally adding a pore-forming agent, stirring at 100 r / min for 10 min until homogeneous to obtain a slurry. The ratio of photoinitiator, crosslinking agent, modified solid electrolyte, and pore-forming agent by mass is 0.5:30:50:20, wherein the photoinitiator is camphorquinone (an α-diketone photoinitiator), the crosslinking agent is dipentaerythritol hexaacrylate, and the pore-forming agent is ethanol.
[0048] The method for preparing the modified solid electrolyte in Example 6 includes: mixing a solid electrolyte (powder) with a solvent, sonicating at a frequency of 40 kHz for 30 min until homogeneous, to obtain a solution containing the solid electrolyte (the content of the solid electrolyte in the solution is 30 wt%), mixing the solution containing the solid electrolyte with an inorganic nanoparticle precursor, stirring at a speed of 80 r / min for 10 min until homogeneous, adding ammonia water (the concentration of NH3 in the ammonia water is 10 wt%) to adjust the pH to 9, stirring and reacting at 70 °C for 2 h, centrifuging to obtain a solid powder, and washing the solid powder with anhydrous ethanol. The mixture was dried under vacuum at 80℃ for 12 h and calcined at 400℃ for 2 h to obtain a modified solid electrolyte (LLZO@Al2O3 / ZrO2). The ratio of the inorganic nanoparticle precursor to the solid electrolyte in the solution was 1:3 by mass. The solvent was a mixture of water and anhydrous ethanol, with a volume ratio of water to anhydrous ethanol of 1:3. The inorganic nanoparticle precursor was a mixture of aluminum isopropoxide and tetrabutyl zirconate, with a mass ratio of aluminum isopropoxide to tetrabutyl zirconate of 1:1. The solid electrolyte was lithium lanthanum zirconium oxide (LLZO).
[0049] Example 7
[0050] A method for preparing a slurry is essentially the same as in Example 6, except that "the crosslinking agent is dipentaerythritol hexaacrylate" is replaced with "a mixture of trimethylolpropane triacrylate and dipentaerythritol hexaacrylate as the crosslinking agent". The ratio of trimethylolpropane triacrylate to dipentaerythritol hexaacrylate by mass is 3:1. Comparative Example 1
[0051] A method for preparing the slurry is basically the same as in Example 1, except that "modified solid electrolyte" is replaced with "solid electrolyte". The solid electrolyte is unmodified lithium lanthanum zirconium oxide (LLZO).
[0052] Comparative Example 2
[0053] A method for preparing a slurry is basically the same as that in Example 1, except that no crosslinking agent is added.
[0054] Comparative Example 3
[0055] A method for preparing a slurry is basically the same as that in Example 1, except that no photoinitiator is added.
[0056] Comparative Example 4
[0057] A method for preparing a slurry is basically the same as that in Example 1, except that no pore-forming agent is added.
[0058] Examples 8-14 and Comparative Examples 5-8
[0059] A method for preparing a diaphragm includes: coating a slurry onto a base film on both sides at a speed of 50 m / min, irradiating it with light for 1 min (the light source is an LED lamp with a wavelength of 465 nm), drying it at 70°C for 5 min, forming a 2 μm coating (1 μm thickness on one side) on the base film, and obtaining the diaphragm. Figure 1 SEM image of the diaphragm prepared from the slurry of Example 7.
[0060] Table 2
[0061]
[0062] The test results of the membranes prepared in Examples 8-14 and Comparative Examples 5-8 are shown in Table 3.
[0063] Table 3
[0064]
[0065] As shown in Table 3, among Examples 8-14, Example 14 exhibits the best overall performance. Specifically, using a mixture of aluminum isopropoxide and tetrabutyl zirconate as the inorganic nanoparticle precursor and a mixture of trimethylolpropane triacrylate and dipentaerythritol hexaacrylate as the crosslinking agent is the optimal choice. The introduction of the photoinitiator significantly improved the membrane's heat resistance, while the introduction of the pore-forming agent effectively improved the membrane's permeability and ionic conductivity. The modified solid electrolyte gave the membrane lower interfacial impedance and higher ionic conductivity.
[0066] The present invention has been described above by way of example. It should be noted that any simple modifications, alterations or other equivalent substitutions that can be made by those skilled in the art without creative effort without departing from the core of the present invention fall within the protection scope of the present invention.
Claims
1. A photocurable composite solid electrolyte membrane, characterized in that, include: The base film and the coating on the base film, wherein the coating is obtained by coating with a slurry, and the raw materials for preparing the slurry include: a modified solid electrolyte, a photoinitiator, a crosslinking agent and a pore-forming agent, wherein the modified solid electrolyte is a solid electrolyte treated with an inorganic nanoparticle precursor, and the inorganic nanoparticle precursor is one or a mixture of aluminum isopropoxide, barium nitrate, tetrabutyl titanate, tetraethyl orthosilicate, tetrabutyl zirconate and zinc acetate.
2. The photocurable composite solid electrolyte membrane according to claim 1, characterized in that, The photoinitiator is one or a mixture of α-hydroxyacetophenone photoinitiators, α-aminoacetophenone photoinitiators, acylphosphine oxide photoinitiators, coumarin photoinitiators, benzophenone photoinitiators, thioxanthone photoinitiators, anthraquinone photoinitiators, and α-diketone photoinitiators.
3. The photocurable composite solid electrolyte membrane according to claim 1, characterized in that, The crosslinking agent is a multifunctional acrylate, which is one or a mixture of polyurethane acrylate, dipentaerythritol hexaacrylate, trimethylolpropane triacrylate and hexanediol diacrylate.
4. The photocurable composite solid electrolyte membrane according to claim 1, characterized in that, The pore-forming agent is at least one of methanol, ethanol, acetone, dichloromethane, ethyl acetate, and isopropanol.
5. The photocurable composite solid electrolyte membrane according to claim 1, characterized in that, The method for preparing modified solid electrolytes includes: mixing a solution containing solid electrolytes and an inorganic nanoparticle precursor until homogeneous, adjusting the pH to 8-11, stirring and reacting at 50-80℃ for 1-2 hours, centrifuging, washing, drying, and calcining at 400-700℃ for 2 hours to obtain modified solid electrolytes. The ratio of the inorganic nanoparticle precursor to the solid electrolyte in the solution containing solid electrolytes is 1:(2-5) by mass.
6. The photocurable composite solid electrolyte membrane according to claim 5, characterized in that, The solid electrolyte is one or more of lithium lanthanum zirconium oxide, tantalum-doped lithium lanthanum zirconium oxide, lithium lanthanum titanium oxide, lithium titanium aluminum phosphate, and lithium germanium aluminum phosphate.
7. The method for preparing the photocurable composite solid electrolyte membrane as described in claim 1, characterized in that, include: The slurry is coated on at least one side of the base membrane, exposed to light, and dried to form a coating on the base membrane, thus obtaining a photocurable composite solid electrolyte membrane.
8. A method for preparing a slurry, characterized in that, include: The photoinitiator, crosslinking agent, modified solid electrolyte and pore-forming agent are mixed until uniform to obtain a slurry. The ratio of photoinitiator, crosslinking agent, modified solid electrolyte and pore-forming agent by mass parts is (0.1~3):(20~40):(30~60):(10~20).
9. Application of modified solid electrolytes, photoinitiators, crosslinking agents and pore-forming agents to synergistically improve the heat resistance of diaphragms.
10. Application of modified solid electrolytes, photoinitiators, crosslinking agents and pore-forming agents to synergistically improve the ionic conductivity of membranes.