A method for modifying a lithium battery pole piece adhesive, the resulting product and its applications
By modifying the lithium battery electrode binder with octanoylthiopropyltriethoxysilane, the problem of insufficient compatibility between the lithium battery electrode binder and the active material and current collector was solved, the bonding strength and high temperature resistance were improved, and the high efficiency and safety of lithium batteries were achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHANDONG YANGGU HUATAI CHEM
- Filing Date
- 2026-03-13
- Publication Date
- 2026-06-05
AI Technical Summary
Existing lithium battery electrode binders have poor compatibility with active materials and current collectors, resulting in insufficient bonding strength. This leads to active material shedding and electrode cracking during long-term charge and discharge processes, high interfacial impedance, and limited high-temperature resistance, which affects the cycle performance and safety of lithium batteries.
The surface of lithium battery electrode binder was modified by using octanoylthiopropyltriethoxysilane. By forming stable chemical bonds with binder molecules, active materials and current collector surfaces, compatibility and bonding strength were improved, interfacial impedance was reduced and high-temperature resistance was improved.
It significantly improves the bonding strength, cycle performance and safety of lithium batteries, reduces AC internal resistance, avoids thermal runaway, and meets the high performance and safety requirements of new energy vehicles and energy storage batteries.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of lithium battery technology, specifically relating to a method for modifying a lithium battery electrode binder, and the application of the obtained modified binder in lithium battery electrodes and lithium batteries, especially suitable for scenarios such as power batteries for new energy vehicles and energy storage batteries. Background Technology
[0002] Lithium-ion batteries, due to their high energy density, long cycle life, and environmental friendliness, have been widely used in various fields such as new energy vehicles, energy storage systems, and portable electronic devices. The performance of the lithium-ion battery electrodes directly determines the overall electrochemical performance, safety, and lifespan of the battery. Lithium-ion battery electrodes mainly consist of current collectors, active materials, conductive agents, and binders. The binder, acting as the "skeleton" of the electrode, plays a crucial role in firmly bonding the active materials and conductive agents to the surface of the current collector, maintaining the structural integrity of the electrode, and ensuring good contact between the active materials and the current collector, reducing interfacial resistance, thereby improving the cycle stability and charge / discharge performance of the lithium-ion battery.
[0003] Currently, commonly used binders for lithium-ion battery electrodes mainly include polyvinylidene fluoride (PVDF) and sodium carboxymethyl cellulose (CMC). Among them, PVDF is the most widely used in positive electrode sheets of power lithium-ion batteries due to its good electrochemical stability and resistance to organic solvents. However, existing binders still have obvious technical defects in practical applications: On the one hand, the surface functional groups of binders such as PVDF and CMC are limited, resulting in poor compatibility with electrode active materials (such as lithium iron phosphate, ternary materials, etc.) and current collectors (such as copper foil, aluminum foil), leading to insufficient bonding strength. During long-term charge-discharge cycles of lithium-ion batteries, problems such as active material shedding and electrode cracking are prone to occur. On the other hand, the interfacial impedance between the binder and the components is relatively large, and the high-temperature resistance is limited. This not only leads to a decrease in the cycle performance of lithium-ion batteries and an increase in internal resistance, but may also cause thermal runaway under high-temperature environments, affecting the safety of lithium-ion batteries.
[0004] To address the aforementioned technical challenges, the industry has conducted extensive research on the modification of lithium battery binders, primarily employing methods such as graft copolymerization, crosslinking modification, and nanoparticle composites. However, these modification methods generally suffer from complex processes, high costs, and limited modification effects, and it is difficult to simultaneously achieve a synergistic improvement in bonding strength, cycle performance, and safety.
[0005] Octanoylthiopropyltriethoxysilane (CAS No.: 220727-26-4) is a sulfur-containing silane compound that is currently mainly used in the tire rubber industry, white / carbon black modification, rubber additives and other fields. However, there are no reports on its application in lithium battery electrode binder modification, and its application potential in the new energy field has not yet been explored. Summary of the Invention
[0006] To address the shortcomings of commonly used binders for lithium-ion battery electrodes, this invention provides a method for modifying lithium-ion battery electrode binders. This method is the first to use octanoylthiopropyltriethoxysilane for surface modification of lithium-ion battery electrode binders (such as PVDF and CMC), filling a technological gap in this field. It effectively solves the technical defects of existing binders, such as insufficient compatibility with active materials and current collectors, low bonding strength, poor cycle performance of lithium-ion batteries, and unsatisfactory safety, and has significant industrial application value.
[0007] This invention utilizes the thio groups and ethoxysilyl groups in the molecular structure of octanoylthiopropyltriethoxysilane to form stable chemical bonds with binder molecules, functional groups on the surface of active materials, and the surface of current collectors. Simultaneously, it improves the surface polarity of the binder, thereby enhancing the compatibility and bonding strength between the binder and the active materials and current collectors. Furthermore, the introduction of octanoylthiopropyltriethoxysilane can reduce the interfacial impedance of the electrode, improve the high-temperature resistance of lithium batteries, prevent thermal runaway, and achieve a synergistic improvement in the cycle performance, safety, and electrochemical performance of lithium batteries. It also expands the application of octanoylthiopropyltriethoxysilane in the new energy field.
[0008] The technical solution of this invention is as follows: A method for modifying a lithium battery electrode binder, the method comprising: Step 1: Add octanoylthiopropyltriethoxysilane to the lithium battery electrode binder solution, then heat to 70-90℃ and stir to react, to obtain the modified binder solution.
[0009] Further, optionally, the method may also include step 2: mixing the modified binder solution obtained in step 1 with water, stirring evenly, allowing it to stand and precipitate, drying the precipitate to obtain a solid modified binder. Depending on the actual application requirements, either a modified binder solution or a solid modified binder can be used. For example, if it is directly used to prepare lithium batteries, a modified binder solution can be used directly without extracting the modified binder.
[0010] Furthermore, in step 1, the lithium battery electrode binder solution is a mixture of lithium battery electrode binder and organic solvent. After the lithium battery electrode binder and organic solvent are mixed, they are stirred at room temperature until completely dissolved. The stirring speed is 300-500 r / min and the stirring time is 1-2 h to ensure that the binder is completely dissolved and to avoid the appearance of undissolved particles, which would affect the modification effect and electrode performance.
[0011] Furthermore, in step 1, the binder is a commonly used binder for lithium battery electrodes, such as one or a mixture of two of polyvinylidene fluoride (PVDF) and sodium carboxymethyl cellulose (CMC), preferably PVDF. The organic solvent is at least one of N-methylpyrrolidone (NMP), N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), and dimethyl sulfoxide (DMSO).
[0012] Furthermore, in step 1, the mass percentage concentration of the lithium battery electrode binder solution is 8-12%, for example, 8%, 9%, 10%, 11%, or 12%.
[0013] Furthermore, in step 1, the amount of octanoylthiopropyltriethoxysilane added is 2-5% of the mass of the lithium battery electrode binder, for example, 2%, 3%, 4%, or 5%. The purity of octanoylthiopropyltriethoxysilane is ≥95% to avoid impurities affecting the modification reaction and the electrochemical performance of the lithium battery.
[0014] Furthermore, in step 1, the modification temperature is 70-90℃, for example, 70℃, 75℃, 80℃, 85℃, 90℃, and the reaction time is 1-2h.
[0015] Furthermore, in step 1, the modification reaction is carried out under stirring at a speed of 400-600 r / min, using a constant temperature oil bath or water bath heating method to ensure uniform and stable reaction temperature and avoid excessively high local temperatures that could lead to binder degradation or decomposition of octanoylthiopropyltriethoxysilane.
[0016] Furthermore, in step 2, the precipitate is dried at 80-100℃, preferably under vacuum, for 2-4 hours.
[0017] This invention also provides a modified binder solution or solid modified binder obtained according to the above method. This modified binder retains the electrochemical stability and processing performance of the original binders (PVDF, CMC), while the surface polarity is improved due to the introduction of octanoylthiopropyltriethoxysilane. It contains functional groups that can form chemical bonds with active materials and current collectors, significantly improving compatibility with active materials such as lithium iron phosphate and current collectors such as copper / aluminum foil. The bonding strength is significantly improved compared to the unmodified binder; and it can improve the problems of poor cycle performance and low safety of lithium batteries caused by the binder.
[0018] The present invention also provides the application of the above-mentioned modified binder solution or solid modified binder in the preparation of lithium batteries and lithium battery electrodes.
[0019] The present invention also provides a lithium battery electrode sheet, which includes a current collector and an active layer disposed on both sides of the current collector, wherein the active layer includes an active material, a conductive agent and the modified binder described above.
[0020] Furthermore, the active material is one or two of lithium iron phosphate and ternary materials (NCM, NCA), preferably lithium iron phosphate; the conductive agent is one or more of conductive carbon black, graphene, and carbon nanotubes; and the current collector is copper foil (for the negative electrode) or aluminum foil (for the positive electrode).
[0021] Further, the active layer is mixed with an organic solvent to form a slurry, which is then coated onto the surface of the current collector. The organic solvent is N-methylpyrrolidone (NMP), N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO), etc. Alternatively, the modified binder solution obtained in step 1 can be used directly, and then the modified binder solution is mixed with the active material and conductive agent to form an active layer slurry. The active layer slurry is coated onto the surface of the current collector, and then dried and rolled to obtain the electrode sheet. The drying temperature is 110-130℃, and the drying time is 1-2 hours; the rolling pressure is 5-10 MPa to ensure a tight bond between the active layer and the current collector, and to maintain the integrity of the electrode sheet structure.
[0022] The present invention also provides a lithium battery, the lithium battery comprising the above-described lithium battery electrode.
[0023] Furthermore, the lithium battery also includes an electrolyte, a separator, and a casing, with the lithium battery electrodes, electrolyte, and separator all encapsulated within the casing.
[0024] Furthermore, the lithium battery uses electrodes prepared with the modified binder of this invention, which reduces the AC internal resistance of the battery by 12.8-23%, maintains a capacity retention rate of ≥85% after 1000 cycles, and significantly improves high-temperature resistance, effectively avoiding thermal runaway under high-temperature conditions, greatly improving safety, and making it suitable for scenarios with high performance and safety requirements such as power batteries for new energy vehicles and energy storage batteries.
[0025] Compared with the prior art, the present invention has the following significant advantages: 1. Outstanding technological innovation: For the first time, octanoylthiopropyltriethoxysilane is applied to the modification of lithium battery electrode binders. The process is simple, the cost is controllable, and the modification effect is significant, filling the technological gap in this field. It breaks the limitation of octanoylthiopropyltriethoxysilane being used only in traditional fields such as rubber and silica modification, and expands its application scope in the new energy field.
[0026] 2. Significant modification effect, solving core technical defects: This invention achieves surface modification of the binder through a simple liquid-phase stirring reaction. The compatibility of the modified binder with electrode active materials (such as lithium iron phosphate) and current collectors is significantly improved, and the bonding strength is increased by more than 25%. At the same time, it reduces the battery AC internal resistance by 12.8-23%, and the capacity retention rate of the lithium battery is ≥85% after 1000 cycles, effectively solving the problems of low bonding strength and poor cycle performance of existing binders.
[0027] 3. Improve lithium battery safety: The introduction of octanoylthiopropyltriethoxysilane can significantly improve the high-temperature resistance of binders and electrodes, effectively preventing thermal runaway of lithium batteries under extreme conditions such as high-temperature charging and discharging and short circuits. This greatly improves the safety of lithium batteries and enhances their overall performance, meeting the needs of high-performance and safety requirements in scenarios such as power batteries for new energy vehicles and energy storage batteries.
[0028] 4. Simple process, controllable cost, and easy to industrialize: The modification method of this invention does not require complex equipment or harsh reaction conditions. It can be completed simply by dissolving, heating and stirring. The reaction time is short (1-2 hours) and the operation is simple. The amount of octanoylthiopropyltriethoxysilane added is small (2-5% of the binder mass), the raw material cost is low, and it is compatible with the existing lithium battery electrode and lithium battery production processes. There is no need to make large-scale modifications to the existing production line, and it is easy to achieve industrial mass production. Detailed Implementation
[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only a part of the embodiments of this invention, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention. The scope of protection of this invention is not limited by the following embodiments.
[0030] It should be noted that the raw materials used in the following examples are all commercially available conventional raw materials, of which octanoylthiopropyltriethoxysilane has a purity of ≥95%, PVDF is lithium battery grade, and N-methylpyrrolidone is analytical grade; the equipment used is all conventional lithium battery production equipment.
[0031] Example 1 A method for modifying a lithium battery electrode binder, the specific steps of which are as follows: ① Preparation of adhesive solution: Weigh 10g PVDF and add it to 90g N-methylpyrrolidone (NMP). Stir at 400r / min for 1.5h at room temperature until PVDF is completely dissolved to form a PVDF solution with a mass concentration of 10%.
[0032] ② Modification reaction: Add 0.3g of octanoylthiopropyltriethoxysilane (3% of the mass of PVDF) to the above PVDF solution, stir evenly, place the mixed solution in a constant temperature oil bath, heat to 80℃, stir at a constant temperature of 500r / min for 1.5h, and after the reaction is completed, cool naturally to room temperature to obtain the modified PVDF binder solution.
[0033] The specific steps for preparing lithium batteries using the modified PVDF binder solution described above are as follows: 1. Preparation of lithium battery electrode sheet: Weigh 85g of lithium iron phosphate (active material), 5g of conductive carbon black (conductive agent), and 10g of the above modified PVDF binder solution. After mixing evenly, coat the aluminum foil (current collector) with a coating machine to a thickness of 100μm. Then place the coated aluminum foil in an oven at 120℃ and dry it for 1.5h. Finally, roll it with a pressure of 8MPa to obtain the positive electrode sheet of lithium battery.
[0034] 2. Preparation of lithium batteries: The above positive electrode sheet is assembled with conventional negative electrode sheet (graphite negative electrode), separator (polyolefin separator) and electrolyte (lithium hexafluorophosphate electrolyte), and packaged in an aluminum-plastic film shell. After standing, formation and aging, the finished lithium battery is obtained.
[0035] Example 2 A method for modifying a lithium battery electrode binder, the specific steps of which are as follows: ① Preparation of adhesive solution: Weigh 8g of PVDF and add it to 92g of N-methylpyrrolidone (NMP). Stir at 300r / min for 2h at room temperature until the PVDF is completely dissolved to form a PVDF solution with a mass concentration of 8%.
[0036] ② Modification reaction: Add 0.16g of octanoylthiopropyltriethoxysilane (2% of the mass of PVDF) to the above PVDF solution, stir evenly, place the mixed solution in a constant temperature water bath, heat to 70℃, stir at a constant temperature of 400r / min for 2h, and after the reaction is completed, cool naturally to room temperature to obtain the modified PVDF adhesive solution.
[0037] The specific steps for preparing lithium batteries using the modified PVDF binder solution described above are as follows: 1. Preparation of lithium battery electrode sheet: Weigh 80g lithium iron phosphate, 8g conductive carbon black, and 12g of the above modified PVDF binder solution, mix them evenly, and coat them on the surface of aluminum foil with a coating thickness of 110μm; dry in an oven at 110℃ for 2h, and roll under a pressure of 5MPa to obtain the positive electrode sheet of lithium battery.
[0038] 2. Preparation of lithium batteries: Same as in Example 1.
[0039] Example 3 A method for modifying a lithium battery electrode binder, the specific steps of which are as follows: ① Preparation of adhesive solution: Weigh 12g PVDF and add it to 88g N-methylpyrrolidone (NMP). Stir at 500r / min for 1h at room temperature until PVDF is completely dissolved to form a PVDF solution with a mass concentration of 12%.
[0040] ② Modification reaction: Add 0.6g of octanoylthiopropyltriethoxysilane (5% of the mass of PVDF) to the above PVDF solution, stir evenly, place the mixed solution in a constant temperature oil bath, heat to 90℃, stir at a constant temperature of 600r / min for 1h, and after the reaction is completed, cool naturally to room temperature to obtain the modified PVDF binder solution.
[0041] The specific steps for preparing lithium batteries using the modified PVDF binder solution described above are as follows: 1. Preparation of lithium battery electrode sheet: Weigh 90g of lithium iron phosphate, 3g of conductive carbon black, and 7g of the above modified PVDF binder solution, mix them evenly, and coat them on the surface of aluminum foil with a coating thickness of 90μm; dry them in an oven at 130℃ for 1h, and roll them under a pressure of 10MPa to obtain the positive electrode sheet of lithium battery.
[0042] 2. Preparation of lithium batteries: Same as in Example 1.
[0043] Comparative Example 1 1. Weigh 10g of PVDF and add it to 90g of N-methylpyrrolidone (NMP). Stir at 400r / min for 1.5h at room temperature until the PVDF is completely dissolved to form an unmodified PVDF solution with a mass concentration of 10%.
[0044] 2. A lithium battery was prepared according to the method of Example 1, except that the modified PVDF binder solution was replaced with an unmodified PVDF solution.
[0045] Comparative Example 2 1. Weigh 8g of PVDF and add it to 92g of N-methylpyrrolidone (NMP). Stir at 300r / min for 2 hours at room temperature until the PVDF is completely dissolved to form an unmodified PVDF solution with a mass concentration of 8%.
[0046] 2. A lithium battery was prepared according to the method of Example 2, except that the modified PVDF binder solution was replaced with an unmodified PVDF solution.
[0047] Comparative Example 3 1. Weigh 12g of PVDF and add it to 88g of N-methylpyrrolidone (NMP). Stir at 500r / min for 1h at room temperature until the PVDF is completely dissolved to form an unmodified PVDF solution with a mass concentration of 12%.
[0048] 2. A lithium battery was prepared according to the method of Example 3, except that the modified PVDF binder solution was replaced with an unmodified PVDF solution.
[0049] Comparative Example 4 1. Weigh 10g PVDF and 0.3g octanoylthiopropyltriethoxysilane, add them to 90g N-methylpyrrolidone (NMP), and stir at 400r / min for 1.5h at room temperature until PVDF and octanoylthiopropyltriethoxysilane are completely dissolved to obtain an adhesive solution.
[0050] 2. Prepare lithium batteries according to the method of Example 1, except that the modified PVDF binder solution used is replaced with the binder solution in step 1 above.
[0051] Comparative Example 5 1. Weigh 8g PVDF and 2g octanoylthiopropyltriethoxysilane, add them to 90g N-methylpyrrolidone (NMP), and stir at 400r / min for 1.5h at room temperature until PVDF and octanoylthiopropyltriethoxysilane are completely dissolved to obtain an adhesive solution.
[0052] 2. Prepare lithium batteries according to the method of Example 1, except that the modified PVDF binder solution used is replaced with the binder solution in step 1 above.
[0053] Comparative Example 6 A method for modifying a lithium battery electrode binder, the specific steps of which are as follows: ① Preparation of adhesive solution: Weigh 10g PVDF and add it to 90g N-methylpyrrolidone (NMP). Stir at 400r / min for 1.5h at room temperature until PVDF is completely dissolved to form a PVDF solution with a mass concentration of 10%.
[0054] ② Modification reaction: Add 0.3g KH-550 (3% of the mass of PVDF) to the above PVDF solution, stir evenly, place the mixed solution in a constant temperature oil bath, heat to 80℃, stir at a constant temperature of 500r / min for 1.5h, and after the reaction is completed, cool naturally to room temperature to obtain the modified PVDF binder solution.
[0055] The modified PVDF binder solution obtained above was used to prepare a lithium battery according to the method in Example 1.
[0056] Comparative Example 7 A method for modifying a lithium battery electrode binder, the specific steps of which are as follows: ① Preparation of adhesive solution: Weigh 10g PVDF and add it to 90g N-methylpyrrolidone (NMP). Stir at 400r / min for 1.5h at room temperature until PVDF is completely dissolved to form a PVDF solution with a mass concentration of 10%.
[0057] ② Modification reaction: Add 0.3g of 3-mercaptopropyltriethoxysilane (3% of the mass of PVDF) to the above PVDF solution, stir evenly, place the mixed solution in a constant temperature oil bath, heat to 80℃, stir at a constant temperature of 500r / min for 1.5h, and after the reaction is completed, cool naturally to room temperature to obtain the modified PVDF binder solution.
[0058] The modified PVDF binder solution obtained above was used to prepare a lithium battery according to the method in Example 1.
[0059] Performance verification The performance of the electrodes and lithium batteries prepared in the above embodiments and comparative examples was tested using the following methods: 1. Testing method: Compatibility test of adhesive with lithium iron phosphate and aluminum foil: The adhesive or modified adhesive solution is dropped onto the surface of the lithium iron phosphate sheet and aluminum foil. The static contact angle of the droplet on the substrate surface is measured using a contact angle meter. The smaller the contact angle, the better the wettability and the better the compatibility.
[0060] Electrode peel strength test: According to GB / T 2792-2014 standard, a universal tensile testing machine was used to conduct a 180° peel test at a tensile speed of 50 mm / min, and the peel strength was recorded.
[0061] Lithium battery cycle performance test: According to GB / T 31484-2015 standard, the battery is charged and discharged at 0.5C for 1000 cycles at 25℃, and the capacity retention rate is calculated.
[0062] Internal resistance test: The AC internal resistance of the battery was measured using a 1kHz AC internal resistance tester.
[0063] High-temperature safety performance test: According to GB / T 31485-2015 standard, place the fully charged battery in a 150℃ oven for 1-2 hours and observe whether there are any phenomena such as bulging, leakage, or thermal runaway.
[0064] 2. The experimental results are shown in Table 1 below: Table 1 As can be seen from the table above: 1. Interface compatibility and bonding strength: The modified binders prepared in Examples 1-3 of this invention have contact angles of 42-50° and 38-46° on the lithium iron phosphate sheet and aluminum foil surface, respectively, which are significantly smaller than those of Comparative Examples 1-3 (72° and 68°), indicating that the modified binders have significantly improved wettability and interface compatibility with the active material and current collector; the corresponding electrode peel strength reaches 2.5-3.2 N / cm, which is 25%-60% higher than that of the unmodified Comparative Examples 1-3 (2.0 N / cm), and the interfacial bonding strength is significantly enhanced, effectively solving the technical defect of insufficient bonding strength of existing binders.
[0065] 2. Cyclic performance: After 1000 cycles, the lithium batteries in Examples 1-3 retained 85%-90% of their capacity, which is much higher than the 65% of Comparative Examples 1-3. This shows that the modified binder of the present invention can effectively maintain the integrity of the electrode structure, reduce problems such as active material shedding and electrode cracking during cycling, significantly improve the cycle stability of lithium batteries, and meet the long-term use requirements of power batteries and energy storage batteries for new energy vehicles.
[0066] 3. Internal Resistance Performance: The internal resistance of the batteries in Examples 1-3 was 30-34 mΩ, which was 12.8%-23% lower than that of Comparative Examples 1-3 (39 mΩ), demonstrating a significant reduction in internal resistance. In contrast, the internal resistance reduction rate of Comparative Examples 4-7 was only 5%-10% compared to Comparative Examples 1-3, far lower than that of this invention. This indicates that the modification with octanoylthiopropyltriethoxysilane in this invention can effectively improve the electrode interface contact state, reduce charge transfer impedance, and enhance the electrochemical transport efficiency of the battery.
[0067] 4. High-temperature safety performance: After being placed at 150°C, Examples 1-3 showed no bulging, leakage, or thermal runaway, demonstrating excellent high-temperature stability. In contrast, the unmodified Comparative Examples 1-3 all exhibited significant bulging and leakage, posing serious safety hazards. Comparative Examples 4-7 also showed varying degrees of bulging, further proving that the modified binder of this invention can significantly improve the high-temperature safety of lithium batteries and effectively suppress the risk of thermal runaway.
[0068] 5. Modification Method and Advantages of Modifier: Comparative Examples 4 and 5 involved direct physical blending of octanoylthiopropyltriethoxysilane with PVDF without constant temperature stirring at 70–90°C. Their peel strength, cycle capacity retention, internal resistance reduction rate, and high-temperature safety were significantly inferior to Examples 1–3, indicating that chemical reaction modification at a specific temperature is key to achieving a significant improvement in adhesive performance. Comparative Examples 6 (using KH-550) and 7 (using 3-mercaptopropyltriethoxysilane) underwent modification, but the improvement in all performance aspects was far lower than that of this invention. This demonstrates that the octanoylthiopropyltriethoxysilane selected in this invention has unique advantages in improving adhesive strength, cycle life, internal resistance performance, and high-temperature safety, exhibiting outstanding non-obviousness.
Claims
1. A method for modifying a lithium battery electrode binder, characterized in that: Octanoylthiopropyltriethoxysilane was added to the lithium battery electrode binder solution, and then the temperature was raised to 70-90℃ and stirred to react, thus obtaining the modified binder solution. Alternatively, the modified binder solution can be further mixed with water, stirred until homogeneous, allowed to stand and precipitate, and the resulting precipitate dried to obtain a solid modified binder.
2. The modification method according to claim 1, characterized in that: The binder is one or both of polyvinylidene fluoride and sodium carboxymethyl cellulose.
3. The modification method according to claim 1 or 2, characterized in that: The mass percentage concentration of the lithium battery electrode binder solution is 8-12%; preferably, the solvent of the lithium battery electrode binder solution is at least one of N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, and dimethyl sulfoxide.
4. The modification method according to claim 1, characterized in that: The amount of octanoylthiopropyltriethoxysilane added is 2-5% of the mass of the lithium battery electrode binder.
5. The modification method according to claim 1, characterized in that: The modification reaction was carried out under stirring at a speed of 400-600 r / min.
6. The modification method according to claim 1, characterized in that: The modification reaction time is 1-2 hours.
7. A modified adhesive solution or solid modified adhesive, characterized in that: Obtained by the modification method according to any one of claims 1-6.
8. The application of the modified binder solution or solid modified binder according to claim 7 in the preparation of lithium batteries and lithium battery electrodes.
9. A lithium battery electrode, characterized in that: It includes a current collector and an active layer disposed on both sides of the current collector. The active layer includes an active material, a conductive agent, and a modified binder. The modified binder is obtained by the modification method according to any one of claims 1-6.
10. A lithium battery, characterized in that: Including the lithium battery electrode as described in claim 9.