Polysiloxane-based solid electrolyte for enhancing interface compatibility and preparation method thereof
The polysiloxane-based solid electrolyte prepared through chemical modification and material composite strategies solves the problem of insufficient interface compatibility and thermal stability of solid electrolytes, achieves higher battery charge and discharge efficiency and cycle stability, and is suitable for high energy density and high safety battery requirements.
Patent Information
- Application Number
- CN202411209478.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-30
- Publication Date
- 2024-12-10
AI Technical Summary
The existing solid electrolytes have shortcomings in interface compatibility, ionic conductivity and thermal stability, resulting in reduced battery charge and discharge efficiency, limited power density and cyclic stability, and improved chemical and mechanical properties in high temperature environments.
Through chemical modification and material composite strategies, a polysiloxane-based solid electrolyte that enhances interface compatibility, including amine protection, substitution reaction and deBoc-protecting steps, forms phenazine tetramine derivatives and COF particles, combined with Polysiloxane, lithium salt and solvent are subjected to high-energy ball milling to form a uniform composite material that is coated onto the substrate to cure.
It significantly improves the interface compatibility and ion transport efficiency of the electrolyte and electrode materials, enhances mechanical and chemical stability, ensures reliability in wide voltage and high temperature environments, and improves the overall performance and safety of the battery.
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Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of solid electrolytes, and in particular to a polysiloxane-based solid electrolyte with enhanced interface compatibility and a preparation method thereof. Background Art
[0002] Solid-state electrolytes, as a core component of lithium-ion batteries, have received widespread attention in recent years. They offer advantages such as improved battery safety and suppression of lithium dendrite growth, making them key materials for achieving high-energy-density batteries. However, existing solid-state electrolytes still have shortcomings in terms of interface compatibility, ionic conductivity, and thermal stability. Traditional solid-state electrolytes exhibit high interfacial impedance with electrode materials, leading to reduced battery charge-discharge efficiency. Simultaneously, the limited ion transport efficiency of solid-state electrolytes restricts battery power density and cycle stability. Furthermore, the chemical stability and mechanical properties of solid-state electrolytes at high temperatures need further improvement to meet the application requirements of batteries under extreme conditions. Therefore, developing novel solid-state electrolyte materials to improve their overall performance has become a current research hotspot. Summary of the Invention
[0003] In view of the technical problems existing in solid electrolytes, such as insufficient interfacial compatibility, limited ionic conductivity, and the need to improve thermal and chemical stability, this invention provides a method for preparing a polysiloxane-based solid electrolyte with enhanced interfacial compatibility, in order to solve these problems and improve the overall performance of solid electrolytes. Through innovative chemical modification and material composite strategies, this invention aims to achieve better electrolyte-electrode interface adhesion, improved ion transport efficiency, enhanced mechanical and chemical stability, and ensure reliability under wide voltage and high temperature environments, meeting the requirements of high energy density and high safety batteries.
[0004] In order to achieve the above purpose, the technical solution adopted by the present invention is:
[0005] A method for preparing a polysiloxane-based solid electrolyte with enhanced interface compatibility, the preparation method comprising the following steps:
[0006] S1: subjecting 2,3,7,8-phenazinetetramine hydrochloride to an amine protection reaction, then subjecting the reaction product to a substitution reaction with trialkylsilane bromide and alkyllithium, and finally subjecting the substitution reaction product to a Boc protection group removal reaction to obtain a phenazinetetramine derivative shown in structural formula I;
[0007] In the formula, R1 is an alkane group with 2 to 5 carbon atoms; R2 is an alkane group with 3 or 4 carbon atoms; R3 is a methyl group or an ethyl group;
[0008] S2: using the phenazine tetramine derivative obtained in step S1 as a first COF monomer and a second COF monomer containing an aldehyde group in the presence of a catalyst, heating and reacting, and forming trialkylsilane-grafted COF particles after precipitation and separation;
[0009] S3: The COF particles obtained in step S2 are uniformly mixed with polysiloxane, lithium salt and solvent by high-energy ball milling, and then coated on a substrate, and cured to obtain the polysiloxane-based solid electrolyte.
[0010] Step S1 of the present application achieves specific chemical modification of phenazine tetramine hydrochloride through amine group protection and deprotection steps, thereby not only enhancing interfacial adhesion but also significantly improving the interfacial compatibility between the electrolyte and the electrode material, thereby reducing interfacial impedance and improving ion transfer efficiency. Furthermore, the introduction of phenazine tetramine derivatives increases the mechanical strength and chemical stability of the electrolyte, helping to maintain the structural integrity of the battery during charge and discharge, and improving the battery's cycling stability.
[0011] Furthermore, step S2 of the present application forms trialkylsilane-grafted COF particles by reacting a phenazine tetramine derivative with an aldehyde-containing monomer under the action of a catalyst. The COF material has a highly ordered porous structure. These structures are linked by stable Schiff bases, thereby significantly enhancing the chemical and thermal stability, providing a guarantee for the application of batteries in high temperature environments. At the same time, the introduction of COF particles further enhances the mechanical strength of the solid electrolyte, optimizes the pore structure, and improves the diffusion rate and transmission performance of ions. The grafting of trialkylsilane further enhances the interfacial compatibility between COF particles and polysiloxane-based electrolytes, reduces the interfacial impedance, and improves the charge and discharge performance of the battery. In addition, the high specific surface area and porosity of COF particles provide more transmission channels for ions, thereby improving the charge and discharge efficiency and cycle stability of the battery.
[0012] In step S3 of this application, COF particles, polysiloxane, lithium salt, and solvent are mixed by high-energy ball milling to prepare a uniform composite material, which is then coated and cured on a substrate to form a polysiloxane-based solid electrolyte. This not only enhances the interfacial compatibility of the polysiloxane-based solid electrolyte but also improves the ionic conductivity of the electrolyte. In addition, the solid electrolyte of this application exhibits better thermal and electrochemical stability, allowing the battery to operate safely over a wider voltage range and in high-temperature environments.
[0013] As a preferred technical solution, the amino protection reaction is to react the 2,3,7,8-phenazinetetramine hydrochloride with BOC anhydride in the presence of an alkaline substance to obtain an N-Boc phenazinetetramine reaction product.
[0014] As a preferred technical solution, the alkaline substance is at least one of triethylamine, diisopropylethylamine, potassium bicarbonate, sodium bicarbonate, and sodium hydroxide.
[0015] As a preferred technical solution, the brominated trialkylsilane is at least one of (3-bromopropyl)triethoxysilane, 4-bromobutyltrimethoxysilane, and 3-bromopropyltrimethoxysilane.
[0016] As a preferred technical solution, the alkyl lithium is at least one of n-butyl lithium, sec-butyl lithium, tert-butyl lithium, isopropyl lithium, and ethyl lithium.
[0017] As a preferred technical solution, the Boc protecting group removal reaction is carried out under acidic conditions.
[0018] As a preferred technical solution, the acidic substance in the acidic condition is hydrochloric acid or trifluoroacetic acid.
[0019] As a preferred technical solution, the second COF monomer containing an aldehyde group is at least one of glyoxal, succinyl dialdehyde, terephthalaldehyde, furan dicarboxaldehyde, and glutaraldehyde.
[0020] As a preferred technical solution, the above-mentioned is at least one of LiClO4, LiPF6, LiBF4, LiTaF6, LiCF3SO3, LiN(SO2CF3)2, LiTFSI, and LiTf.
[0021] Another aspect of the present invention is to provide a polysiloxane-based solid electrolyte with enhanced interface compatibility, wherein the polysiloxane-based solid electrolyte is prepared using the above-mentioned method for preparing a polysiloxane-based solid electrolyte with enhanced interface compatibility.
[0022] Beneficial effects of the present invention:
[0023] The present invention's method for preparing a polysiloxane-based solid electrolyte with enhanced interfacial compatibility introduces a phenazine tetramine derivative to form a COF structure, which not only achieves chemical bonding between the electrolyte and electrode materials but also significantly improves interfacial adhesion and ion transport efficiency. This design enhances the electrolyte's mechanical strength and chemical stability, as well as its thermal stability and electrochemical window, helping to improve the overall performance and safety of the battery.
[0024] In general, the polysiloxane-based solid electrolyte of the present invention not only exhibits excellent interface compatibility and ionic conductivity, but also ensures application reliability in a wide voltage and high-temperature environment. It has strong overall comprehensive performance and can meet the long-term durability and stability requirements of high-energy density and high-safety batteries. DETAILED DESCRIPTION
[0025] The following description is intended to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are merely examples, and those skilled in the art may conceive of other obvious variations.
[0026] Example 1
[0027] The method for preparing a polysiloxane-based solid electrolyte with enhanced interface compatibility in this embodiment comprises the following steps:
[0028] S1: 2,3,7,8-phenazinetetramine hydrochloride was subjected to an amino protection reaction. Specifically, 2,3,7,8-phenazinetetramine hydrochloride (0.25 mol) and dichloromethane were added to a 1L flask, triethylamine (0.5 mol) was added dropwise, and then BOC anhydride (1.05 mol) was added dropwise while controlling the temperature below 10°C. After the addition was completed, the temperature was naturally raised to room temperature for an amino protection reaction for 5 hours. The reaction product was separated and used in the next step. Then, in a 500ml round-bottom flask protected by nitrogen, 0.2 mol of the reaction product after the above amino protection reaction was added to 150ml anhydrous tetrahydrofuran (THF), and 120ml of ethanol was added dropwise under vigorous stirring. l cyclohexane-ether solution containing 20% n-butyl lithium (cyclohexane and ether are prepared in a volume ratio of 7:3), the reaction temperature is controlled at -24°C (ice-salt bath), and the substitution reaction time is 2 hours; at room temperature, 140g of (3-bromopropyl)triethoxysilane is added dropwise to the reaction flask. After the addition is complete, the temperature is raised to 45°C, and the substitution reaction is continued for 10 hours. After separation, it is used in the next step; finally, the reaction product (0.15mol) of the above substitution reaction and dichloromethane are added to a three-necked flask, and hydrochloric acid is added at 10°C to remove the Boc protecting group. The reaction system gradually becomes turbid. After the reaction is completed, it is filtered and dried to obtain a phenazine tetramine derivative.
[0029] S2: In a 45°C warm water bath, 0.15 mol of the phenazine tetramine derivative obtained in step S1 as the first COF monomer and 150 ml of glyoxal, a second COF monomer containing an aldehyde group, were added to a flask. An appropriate amount of acetic acid solution as a catalyst was then added and stirred to mix evenly. The first COF monomer and the second COF monomer were heated to 110°C in the presence of the acetic acid solution as a catalyst and reacted for 1 hour. COF particles grafted with trialkylsilane were formed after precipitation and separation.
[0030] S3: The COF particles obtained in step S2 are mixed uniformly with polydimethylsiloxane (PDMS), LiPF6, and propylene carbonate through high-energy ball milling, then coated onto a substrate and cured to obtain the polysiloxane solid electrolyte. The mass ratio of the COF particles to polysiloxane, lithium salt, and solvent is 8:100:12:80.
[0031] Example 2
[0032] The method for preparing a polysiloxane-based solid electrolyte with enhanced interface compatibility in this embodiment comprises the following steps:
[0033] S1: The amine protection reaction of 2,3,7,8-phenazinetetramine hydrochloride was carried out in a 1L flask by adding 0.25 mol of 2,3,7,8-phenazinetetramine hydrochloride and dichloromethane, followed by the dropwise addition of 0.5 mol of sodium hydroxide. Then, BOC anhydride (1.05 mol) was added dropwise while maintaining the temperature below 10°C. After the addition was complete, the mixture was allowed to rise naturally to room temperature for 5 hours for the amine protection reaction. The reaction product was then separated and used in the next step. Next, in a 500ml round-bottom flask under nitrogen protection, 0.2 mol of the reaction product from the above amine protection reaction was added to 150ml of anhydrous tetrahydrofuran (THF), and 12% of the product was added dropwise under vigorous stirring. 0 ml of a cyclohexane-diethyl ether solution containing 20% tert-butyllithium (cyclohexane and diethyl ether were prepared at a volume ratio of 7:3) was used. The reaction temperature was controlled at -24℃ (ice-salt bath), and the substitution reaction time was 2 hours. At room temperature, 140 g of 4-bromobutyltrimethoxysilane was added dropwise to the reaction flask. After the addition was complete, the temperature was raised to 45℃, and the substitution reaction was continued for 10 hours. After separation, the product was used for the next step. Finally, the reaction product (0.15 mol) of the above substitution reaction and dichloromethane were added to a three-necked flask. Hydrochloric acid was added at 10℃ to carry out the deprotection reaction of the Boc group. The reaction system gradually became turbid. After the reaction was completed, the system was filtered and dried to obtain the phenazine tetraamine derivative.
[0034] S2: In a 45℃ warm water bath, 0.15mol of the phenazine tetraamine derivative obtained in step S1 as the first COF monomer and 150ml of the second COF monomer containing aldehyde group, butanedialdehyde, were added to a flask. Then, an appropriate amount of acetic acid solution was added as a catalyst and stirred until homogeneous. The first COF monomer and the second COF monomer were heated to 110℃ and reacted for 1h under the action of the acetic acid solution as a catalyst. After precipitation and separation, COF particles grafted with trialkylsilane were formed.
[0035] S3: The COF particles obtained in step S2 are mixed with polydimethylsiloxane (PDMS), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), and propylene carbonate by high-energy ball milling, and then coated on a substrate. After curing, the polysiloxane-based solid electrolyte is obtained. The mass ratio of the COF particles to the polysiloxane, lithium salt, and solvent is 7:100:13:80.
[0036] Example 3
[0037] The method for preparing a polysiloxane-based solid electrolyte with enhanced interface compatibility in this embodiment comprises the following steps:
[0038] S1: 2,3,7,8-phenazinetetramine hydrochloride was subjected to an amino protection reaction. Specifically, 2,3,7,8-phenazinetetramine hydrochloride (0.25 mol) and dichloromethane were added to a 1L flask, triethylamine (0.5 mol) was added dropwise, and then BOC anhydride (1.05 mol) was added dropwise while controlling the temperature below 10°C. After the addition was completed, the temperature was naturally raised to room temperature for an amino protection reaction for 5 hours. The reaction product was separated and used in the next step. Then, in a 500ml round-bottom flask protected by nitrogen, 0.2 mol of the reaction product after the above amino protection reaction was added to 150ml anhydrous tetrahydrofuran (THF), and 120 ml of a cyclohexane-ether solution containing 20% isopropyl lithium (cyclohexane and ether are prepared in a volume ratio of 7:3), the reaction temperature is controlled at -24°C (ice-salt bath), and the substitution reaction time is 2 hours; at room temperature, 140g of 3-bromopropyltrimethoxysilane is added dropwise to the reaction flask, and after the addition is complete, the temperature is raised to 45°C, and the substitution reaction is continued for 10 hours. After separation, it is used in the next step; finally, the reaction product (0.15mol) of the above substitution reaction and dichloromethane are added to a three-necked flask, and hydrochloric acid is added at 10°C to carry out a Boc protecting group removal reaction. The reaction system gradually becomes turbid. After the reaction is completed, it is filtered and dried to obtain a phenazine tetramine derivative.
[0039] S2: In a 45°C warm water bath, 0.15 mol of the phenazine tetramine derivative obtained in step S1 as a first COF monomer and 150 ml of glutaraldehyde, a second COF monomer containing an aldehyde group, were added to a flask. An appropriate amount of acetic acid solution as a catalyst was then added and stirred to mix evenly. The first COF monomer and the second COF monomer were heated to 110°C in the presence of the acetic acid solution as a catalyst and reacted for 1 hour. COF particles grafted with trialkylsilane were formed after precipitation and separation.
[0040] S3: The COF particles obtained in step S2 are uniformly mixed with polydimethylsiloxane (PDMS), lithium perchlorate (LiClO4), and propylene carbonate by high-energy ball milling, and then coated on a substrate. After curing, the polysiloxane-based solid electrolyte is obtained. The mass ratio of the COF particles to the polysiloxane, lithium salt, and solvent is 9:100:11:80.
[0041] Comparative Example 1
[0042] The raw material composition and preparation steps of the polysiloxane-based solid electrolyte with enhanced interface compatibility in this comparative example are basically the same as those in Example 1, except that, in the preparation method of this comparative example, 2,3,7,8-phenazinetetramine hydrochloride is not subjected to the chemical structure modification reaction of step S1.
[0043] Comparative Example 2
[0044] The preparation method of the polysiloxane solid electrolyte with enhanced interfacial compatibility in this comparative example is basically the same as that in Example 1 in terms of raw material composition and preparation steps. The difference is that step S2 is not included in the preparation method of this comparative example.
[0045] The polysiloxane-based solid electrolytes with enhanced interface compatibility prepared in Examples 1 to 3 and Comparative Examples 1 to 2 were subjected to performance tests, and the performance results are shown in Table 1:
[0046] Among them, the mechanical strength performance test method is as follows: the sample is cut into strips with a length of 120 mm and a width of 15 mm. The mechanical strength of the solid electrolyte is evaluated by tensile testing on a universal testing machine, with tensile strength and elongation at break as the evaluation indicators.
[0047] The ionic conductivity performance was tested by connecting the prepared solid electrolyte sample to an AC impedance spectroscopy instrument and measuring the ionic conductivity of the solid electrolyte through AC impedance spectroscopy.
[0048] Interfacial impedance performance testing was conducted by sandwiching a solid electrolyte sample between positive and negative electrode materials (lithium manganese oxide for positive electrode and lithium titanate for negative electrode) to form a complete coin cell structure. The interfacial impedance between the solid electrolyte and the positive and negative electrode materials was tested using an electrochemical workstation via electrochemical impedance spectroscopy.
[0049] Thermal stability testing method: The thermal stability of the sample material is evaluated by thermogravimetric analysis (TGA), specifically by heating from room temperature to 250°C at a heating rate of 5°C / min, and the thermal stability is evaluated by the mass loss rate of the sample.
[0050] Electrochemical stability window testing method: The electrochemical stability window of an electrolyte is determined by cyclic voltammetry (CV), which measures the maximum voltage range that the electrolyte can withstand without decomposition. Table 1
[0051] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions only describe the principles of the present invention. Various changes and improvements are possible without departing from the spirit and scope of the present invention, and such changes and improvements fall within the scope of the invention as claimed.
Claims
1. A method for preparing a polysiloxane-based solid electrolyte with enhanced interface compatibility, characterized in that: The preparation method comprises the following steps: S1: subjecting 2,3,7,8-phenazinetetramine hydrochloride to an amine protection reaction, then subjecting the reaction product to a substitution reaction with trialkylsilane bromide and alkyllithium, and finally subjecting the reaction product of the substitution reaction to a Boc protection group removal reaction to obtain a phenazinetetramine derivative shown in structural formula I; In the formula, R1 is an alkane group with 2 to 5 carbon atoms; R2 is an alkane group with 3 or 4 carbon atoms; R3 is a methyl group or an ethyl group; S2: using the phenazine tetramine derivative obtained in step S1 as a first COF monomer and a second COF monomer containing an aldehyde group under the action of a catalyst, heating and reacting, and forming COF particles grafted with trialkylsilane after precipitation and separation; S3: The COF particles obtained in step S2 are mixed evenly with polysiloxane, lithium salt and solvent by high-energy ball milling, and then coated on a substrate, and cured to obtain the polysiloxane-based solid electrolyte.
2. The method for preparing a polysiloxane-based solid electrolyte with enhanced interface compatibility as claimed in claim 1, characterized in that: The amine protection reaction is that the 2,3,7,8-phenazinetetramine hydrochloride reacts with BOC anhydride in the presence of an alkaline substance to obtain an N-Boc phenazinetetramine reaction product.
3. The method for preparing a polysiloxane-based solid electrolyte with enhanced interface compatibility as claimed in claim 1, characterized in that: The alkaline substance is at least one of triethylamine, diisopropylethylamine, potassium bicarbonate, sodium bicarbonate and sodium hydroxide.
4. The method for preparing a polysiloxane-based solid electrolyte with enhanced interface compatibility as claimed in claim 1, characterized in that: The brominated trialkylsilane is at least one of (3-bromopropyl)triethoxysilane, 4-bromobutyltrimethoxysilane and 3-bromopropyltrimethoxysilane.
5. The method for preparing a polysiloxane-based solid electrolyte with enhanced interface compatibility as claimed in claim 1, characterized in that: The alkyl lithium is at least one of n-butyl lithium, sec-butyl lithium, tert-butyl lithium, isopropyl lithium and ethyl lithium.
6. The method for preparing a polysiloxane-based solid electrolyte with enhanced interface compatibility as claimed in claim 1, characterized in that: The deprotection reaction of the Boc protecting group is carried out under acidic conditions.
7. The method for preparing a polysiloxane-based solid electrolyte with enhanced interface compatibility as claimed in claim 1, characterized in that: The acidic substance in the acidic condition is hydrochloric acid or trifluoroacetic acid.
8. The method for preparing a polysiloxane-based solid electrolyte with enhanced interface compatibility as claimed in claim 1, characterized in that: The second COF monomer containing an aldehyde group is at least one of glyoxal, succinaldehyde, terephthalaldehyde, furan dicarboxaldehyde, and glutaraldehyde.
9. The method for preparing a polysiloxane-based solid electrolyte with enhanced interface compatibility as claimed in claim 1, characterized in that: The present invention is at least one of LiClO4, LiPF6, LiBF4, LiTaF6, LiCF3SO3, LiN(SO2CF3)2, LiTFSI and LiTf.
10. A polysiloxane-based solid electrolyte with enhanced interface compatibility, characterized in that: The polysiloxane-based solid electrolyte is prepared by the method for preparing a polysiloxane-based solid electrolyte with enhanced interface compatibility as claimed in any one of claims 1 to 9.