Preparation method and application of composite solid electrolyte film containing poly (ethyl acrylate-chloroethyl ether)
By adding LLZTO and ethyl chloroethyl ether polyacrylate to a PEO-LiTFSI solution, a composite solid electrolyte film was prepared, which solved the problems of filler agglomeration and poor interfacial compatibility, and improved the electrolyte's cycle performance and ionic conductivity, making it suitable for electric and new energy vehicles.
Patent Information
- Application Number
- CN202511911942.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-17
- Publication Date
- 2026-03-03
AI Technical Summary
Existing composite solid electrolytes using polyethylene oxide as the matrix and lithium lanthanum zirconium tantalum oxide as the filler have problems such as filler agglomeration and poor electrode/electrolyte interface compatibility.
A method for preparing composite solid electrolyte films containing ethyl ethyl acrylate (EYE) was adopted. By sequentially adding LLZTO and EYE to a PEO-LiTFSI solution, the films were prepared by heating, stirring, and solution casting. This method improves the compatibility between the LLZTO/PEO-LiTFSI composite solid electrolyte film and the electrode interface, and enhances the dispersibility of LLZTO particles in PEO.
It improves the cycling and rate performance of composite solid electrolyte films, increases ionic conductivity, and enhances electrochemical performance, making it suitable for applications in electrical and new energy vehicles.
Smart Images
Figure CN121601768A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of solid electrolyte technology. Background Technology
[0002] In recent years, the rapid development of the power and electrical industries has led to increasingly higher requirements for energy storage equipment. Compared to liquid electrolytes, solid electrolytes are favored by the lithium battery industry due to their advantages such as better safety and higher energy density. Lithium lanthanum zirconium tantalum oxide (LLZTO) oxide filler has become one of the most widely used materials in lithium metal batteries due to its wide electrochemical window and non-reaction with lithium metal. Meanwhile, researchers have noted the excellent high-temperature and mechanical properties of polyethylene oxide (PEO). However, its relatively poor electrochemical stability limits its application. Therefore, researchers are dedicated to solving this technical challenge by incorporating inorganic ceramic fillers into polymers to improve the electrochemical window of polymer electrolytes and reduce Li-energy density. + The migration activation energy and ionic conductivity are improved. However, composite solid electrolytes based on polyethylene oxide (PEO) and lithium lanthanum zirconium tantalum oxide (LLZTO) filler suffer from filler agglomeration and poor electrode / electrolyte interface compatibility. Summary of the Invention
[0003] This invention aims to address the problems of filler agglomeration and poor electrode / electrolyte interface compatibility in existing composite solid electrolytes using polyethylene oxide (PEO) as the matrix and lithium lanthanum zirconium tantalum oxide (LLZTO) as the filler. Furthermore, it provides a method for preparing and applying a composite solid electrolyte film containing ethyl polyacrylate chloroethyl ether.
[0004] A method for preparing a composite solid electrolyte film containing ethyl polyacrylate chloroethyl ether comprises the following steps:
[0005] I. Preparation of LLZTO / PEO-LiTFSI solution containing polyethyl acrylate chloroethyl ether:
[0006] ① Add polyethylene oxide and lithium bis(trifluoromethanesulfonyl)imide to an acetonitrile solution and heat and stir until the polyethylene oxide is completely dissolved to obtain a PEO-LiTFSI solution;
[0007] ② Add lithium lanthanum zirconium tantalum oxide to acetonitrile solution and sonicate at room temperature until uniformly dispersed to obtain LLZTO suspension;
[0008] ③ Add the LLZTO suspension to the PEO-LiTFSI solution and heat and stir to obtain the LLZTO / PEO-LiTFSI solution;
[0009] ④ Add ethyl acrylate chloroethyl ether to the LLZTO / PEO-LiTFSI solution and heat and stir until the ethyl acrylate chloroethyl ether is completely dissolved to obtain the DE / LLZTO / PEO-LiTFSI solution;
[0010] II. Preparation of composite solid electrolyte films containing polyethyl acrylate chloroethyl ether:
[0011] Inside the glove box, the DE / LLZTO / PEO-LiTFSI solution was cast into a film, then dried and hot-pressed to obtain a composite solid electrolyte film containing ethyl acrylate chloroethyl ether.
[0012] The mass percentage of polyethyl acrylate chloroethyl ether in the composite solid electrolyte film containing polyethyl acrylate chloroethyl ether is 2% to 8%.
[0013] Application of a composite solid electrolyte film containing ethyl acrylate chloroethyl ether in all-solid-state lithium metal batteries.
[0014] The beneficial effects of this invention are:
[0015] (1) The present invention provides a method for preparing a composite solid electrolyte film (DE / LLZTO / PEO-LiTFSI film) containing ethyl acrylate chloroethyl ether. First, PEO and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) are added to an acetonitrile solution, followed by the sequential addition of LLZTO and ethyl acrylate chloroethyl ether (DE). Since PEO is difficult to dissolve, thorough stirring under heating conditions is necessary before the film is prepared using a solution casting method. Introducing ceramic fillers with high conductivity into the PEO polymer matrix usually affects other properties and can easily lead to defects and performance degradation. The DE used in this invention improves the compatibility between the LLZTO / PEO-LiTFSI composite solid electrolyte film and the electrode interface, enhancing the cycle and rate performance of the composite solid electrolyte film. Furthermore, DE improves the dispersion of LLZTO particles in PEO, increasing the ionic conductivity of the DE / LLZTO / PEO-LiTFSI film.
[0016] (2) The LLZTO / PEO-LiTFSI composite solid electrolyte film containing polyethyl acrylate chloroethyl ether prepared by the method of this invention has excellent electrochemical performance and can be widely used in advanced fields such as electrical and new energy vehicles. The preparation process of this invention is simple, economical and practical, effectively saving resources, and providing a good strategy for developing new solid electrolyte materials. Attached Figure Description
[0017] Figure 1 For comparison, the surface scanning electron microscope image of the LLZTO / PEO-LiTFSI film prepared in Experiment 3 is shown.
[0018] Figure 2 This is a scanning electron microscope (SEM) image of the DE / LLZTO / PEO-LiTFSI film prepared in Example 3.
[0019] Figure 3 The ionic conductivity diagram at 60°C is used to compare the LLZTO / PEO-LiTFSI membranes with different LLZTO addition amounts in Experiments 1 to 5 and the DE / LLZTO / PEO-LiTFSI membranes with different DE addition amounts in Examples 1 to 4.
[0020] Figure 4 Electrochemical impedance spectroscopy of stainless steel symmetric cells assembled using LLZTO / PEO-LiTFSI films with different LLZTO addition amounts in comparative experiments one through five at 60 °C.
[0021] Figure 5 Electrochemical impedance spectroscopy of stainless steel symmetric cells assembled using DE / LLZTO / PEO-LiTFSI films with different DE addition amounts in Examples 1 to 4 at 60°C.
[0022] Figure 6 The lithium-ion symmetric battery assembled using the LLZTO / PEO-LiTFSI film prepared in Comparative Experiment 3 and the lithium-ion symmetric battery assembled using the DE / LLZTO / PEO-LiTFSI film prepared in Example 3 both showed a current density of 0.1 mA / cm² at 60°C. 2 The constant current density long-cycle test graphs are shown. a is a Li|LLZTO / PEO-LiTFSI|Li symmetric cell, and b is a Li|DE / LLZTO / PEO-LiTFSI|Li symmetric cell.
[0023] Figure 7 The limiting current density test graphs at 60°C are shown for the lithium symmetric battery assembled using the LLZTO / PEO-LiTFSI film prepared in Comparative Experiment 3 and the lithium symmetric battery assembled using the DE / LLZTO / PEO-LiTFSI film prepared in Example 3. a is the Li|LLZTO / PEO-LiTFSI|Li symmetric battery, and b is the Li|DE / LLZTO / PEO-LiTFSI|Li symmetric battery.
[0024] Figure 8The graph shows the rate test results at 60°C for the full cell assembled using the LLZTO / PEO-LiTFSI film prepared in Comparative Experiment 3 and the full cell assembled using the DE / LLZTO / PEO-LiTFSI film prepared in Example 3. ■ represents the specific capacity of the Li|LLZTO / PEO-LiTFSI|LFP full cell, ● represents the specific capacity of the Li|DE / LLZTO / PEO-LiTFSI|LFP full cell, ▲ represents the coulombic efficiency of the Li|LLZTO / PEO-LiTFSI|LFP full cell, and ▼ represents the coulombic efficiency of the Li|DE / LLZTO / PEO-LiTFSI|LFP full cell. Detailed Implementation
[0025] Specific Implementation Method 1: This implementation method is a method for preparing a composite solid electrolyte film containing ethyl polyacrylate chloroethyl ether, which is carried out according to the following steps:
[0026] I. Preparation of LLZTO / PEO-LiTFSI solution containing polyethyl acrylate chloroethyl ether:
[0027] ① Add polyethylene oxide and lithium bis(trifluoromethanesulfonyl)imide to an acetonitrile solution and heat and stir until the polyethylene oxide is completely dissolved to obtain a PEO-LiTFSI solution;
[0028] ② Add lithium lanthanum zirconium tantalum oxide to acetonitrile solution and sonicate at room temperature until uniformly dispersed to obtain LLZTO suspension;
[0029] ③ Add the LLZTO suspension to the PEO-LiTFSI solution and heat and stir to obtain the LLZTO / PEO-LiTFSI solution;
[0030] ④ Add ethyl acrylate chloroethyl ether to the LLZTO / PEO-LiTFSI solution and heat and stir until the ethyl acrylate chloroethyl ether is completely dissolved to obtain the DE / LLZTO / PEO-LiTFSI solution;
[0031] II. Preparation of composite solid electrolyte films containing polyethyl acrylate chloroethyl ether:
[0032] Inside the glove box, the DE / LLZTO / PEO-LiTFSI solution was cast into a film, then dried and hot-pressed to obtain a composite solid electrolyte film containing ethyl acrylate chloroethyl ether.
[0033] The mass percentage of polyethyl acrylate chloroethyl ether in the composite solid electrolyte film containing polyethyl acrylate chloroethyl ether is 2% to 8%.
[0034] The beneficial effects of this embodiment are:
[0035] (1) This embodiment provides a method for preparing a composite solid electrolyte film (DE / LLZTO / PEO-LiTFSI film) containing ethyl acrylate chloroethyl ether. First, PEO and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) are added to an acetonitrile solution, followed by the sequential addition of LLZTO and ethyl acrylate chloroethyl ether (DE). Since PEO is difficult to dissolve, thorough stirring is required under heating conditions, and the film is then prepared using a solution casting method. Introducing ceramic fillers with high conductivity into the PEO polymer matrix usually affects other properties and can easily lead to other defects, resulting in performance degradation. However, the DE used in this embodiment improves the compatibility between the LLZTO / PEO-LiTFSI composite solid electrolyte film and the electrode interface, enhancing the cycle and rate performance of the composite solid electrolyte film. Furthermore, DE improves the dispersion of LLZTO particles in PEO, increasing the ionic conductivity of the DE / LLZTO / PEO-LiTFSI film.
[0036] (2) The LLZTO / PEO-LiTFSI composite solid electrolyte film containing ethyl chloroethyl acrylate prepared by the method of this embodiment exhibits excellent electrochemical performance and can be widely used in advanced fields such as electrical and new energy vehicles. The preparation process of this invention is simple, economical, and practical, effectively saving resources and providing a good strategy for developing new solid electrolyte materials.
[0037] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that: the total mass ratio of polyethylene oxide and lithium bis(trifluoromethanesulfonyl)imide to the volume ratio of the acetonitrile solution in step one ① is 1g:(10~12)mL; the polyethylene oxide in step one ① is pretreated polyethylene oxide, and the pretreatment specifically involves drying at a temperature of 50℃~60℃ for 5h~6h; in step one ①, polyethylene oxide and lithium bis(trifluoromethanesulfonyl)imide are added to the acetonitrile solution, and heated and stirred at a temperature of 50℃~60℃ and a stirring speed of 300r / min~450r / min for 6h~8h until the polyethylene oxide is completely dissolved. Everything else is the same as in Specific Implementation Method One.
[0038] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One or Two in that: the mass ratio of lithium lanthanum zirconium tantalum oxide to acetonitrile solution in step one ② is 1 g:(8~10) mL; the particle size of lithium lanthanum zirconium tantalum oxide in step one ② is 5 μm~8 μm; in step one ②, lithium lanthanum zirconium tantalum oxide is added to the acetonitrile solution and ultrasonically stirred for 30 min~45 min at room temperature and ultrasonic power of 10 W / L~20 W / L until uniformly dispersed. Everything else is the same as in Specific Implementation Method One or Two.
[0039] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that: the mass ratio of polyethylene oxide to lithium bis(trifluoromethanesulfonyl)imide in the LLZTO / PEO-LiTFSI solution in step one (③) is 1:(0.362~0.407); the mass ratio of polyethylene oxide to lithium lanthanum zirconium tantalum oxide in the LLZTO / PEO-LiTFSI solution in step one (③) is 1:(0.074~0.352); in step one (③), the LLZTO suspension is added to the PEO-LiTFSI solution, and the mixture is heated and stirred for 6 to 8 hours at a temperature of 50℃~60℃ and a stirring speed of 450 r / min~600 r / min. Everything else is the same as in Specific Implementation Methods One to Three.
[0040] Specific Implementation Method Five: This implementation method differs from Specific Implementation Methods One to Four in that: in step one, ④, polyethyl acrylate chloroethyl ether is added to the LLZTO / PEO-LiTFSI solution, and heated and stirred for 24 to 48 hours at a temperature of 50℃~60℃ and a stirring speed of 450 r / min~600 r / min until the polyethyl acrylate chloroethyl ether is completely dissolved. Everything else is the same as in Specific Implementation Methods One to Four.
[0041] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in that: in step two, the DE / LLZTO / PEO-LiTFSI solution is placed in the transition chamber of a glove box and evacuated for 10-20 minutes. Then, it is transferred to the glove box and uniformly poured onto a polytetrafluoroethylene mold. It is dried at room temperature in the glove box for 12-24 hours. Afterward, it is removed from the glove box and first dried in a forced-air oven at 50-60°C for 12-24 hours, then dried in a vacuum oven at 50-60°C for 12-24 hours. After drying, the film is hot-pressed in a hot rolling mill at 45-55°C. The water and oxygen content in the glove box is <0.01 ppm. Everything else is the same as in Specific Implementation Methods One to Five.
[0042] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods One to Six in that: a layer of plastic sheet is provided inside the polytetrafluoroethylene mold; during hot pressing in the hot rolling mill, the film is sandwiched between the two plastic sheets. Everything else is the same as Specific Implementation Methods One to Six.
[0043] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Methods One to Seven in that the polytetrafluoroethylene mold and plastic sheet are pre-treated, and the pretreatment is carried out according to the following steps: first, wash with deionized water 1 to 3 times, then rinse with anhydrous ethanol 1 to 2 times, then wipe clean with non-woven cloth, and finally dry at 50℃ to 60℃ for 20 to 30 minutes. Everything else is the same as in Specific Implementation Methods One to Seven.
[0044] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Methods One to Eight in that the thickness of the composite solid electrolyte film containing ethyl polyacrylate chloroethyl ether prepared in step two is 100 μm to 200 μm. Everything else is the same as in Specific Implementation Methods One to Eight.
[0045] Specific Implementation Method 10: This implementation method describes the application of a composite solid electrolyte film containing ethyl acrylate chloroethyl ether, which is used in all-solid-state lithium metal batteries.
[0046] The beneficial effects of the present invention are verified using the following embodiments:
[0047] Example 1:
[0048] A method for preparing a composite solid electrolyte film containing ethyl polyacrylate chloroethyl ether comprises the following steps:
[0049] I. Preparation of LLZTO / PEO-LiTFSI solution containing polyethyl acrylate chloroethyl ether:
[0050] ① Add 1g of polyethylene oxide and 0.407g of lithium bis(trifluoromethanesulfonyl)imide to 14mL of acetonitrile solution, and heat and stir for 8h at a temperature of 50℃ and a stirring speed of 450r / min until the polyethylene oxide is completely dissolved to obtain a PEO-LiTFSI solution.
[0051] The polyethylene oxide mentioned is pretreated polyethylene oxide, and the pretreatment specifically involves drying at a temperature of 50°C for 6 hours.
[0052] ② Add 0.248g of lithium lanthanum zirconium tantalum oxide to 2mL of acetonitrile solution, and sonicate for 2h at room temperature and ultrasonic power of 15W / L until uniformly dispersed to obtain LLZTO suspension.
[0053] The particle size of the lithium lanthanum zirconium tantalum oxide is 5μm~8μm;
[0054] ③ Add the LLZTO suspension to the PEO-LiTFSI solution and heat and stir for 8 hours at a temperature of 50℃ and a stirring speed of 540r / min to obtain the LLZTO / PEO-LiTFSI solution.
[0055] ④ Add 0.034 g of ethyl acrylate chloroethyl ether to the LLZTO / PEO-LiTFSI solution, and heat and stir for 48 h at a temperature of 50℃ and a stirring speed of 500 r / min until the ethyl acrylate chloroethyl ether is completely dissolved to obtain the DE / LLZTO / PEO-LiTFSI solution.
[0056] II. Preparation of composite solid electrolyte films containing polyethyl acrylate chloroethyl ether:
[0057] The DE / LLZTO / PEO-LiTFSI solution was placed in the transition chamber of a glove box and evacuated for 20 minutes. Then it was transferred to the glove box and uniformly poured onto a polytetrafluoroethylene mold. It was dried at room temperature in the glove box for 24 hours. Then it was removed from the glove box and dried in a forced-air oven at 55°C for 12 hours, and then dried in a vacuum oven at 60°C for 12 hours. After drying, the film was hot-pressed in a hot roll mill at 45°C to obtain a composite solid electrolyte film containing ethyl acrylate chloroethyl ether.
[0058] The mass percentage of polyethyl acrylate chloroethyl ether in the composite solid electrolyte membrane (DE / LLZTO / PEO-LiTFSI membrane) is 2%.
[0059] The oxygen content in the glove box is <0.01 ppm.
[0060] The polytetrafluoroethylene mold has a layer of plastic plate inside, and the mold is covered with aluminum foil to prevent liquid from overflowing; during hot pressing in the hot roll mill, the film is sandwiched between the two plastic plates.
[0061] The polytetrafluoroethylene mold and plastic sheet are pre-treated, and the pretreatment is carried out in the following steps: first, wash with deionized water twice, then rinse with anhydrous ethanol twice, then wipe clean with non-woven cloth, and finally dry at 60°C for 30 minutes.
[0062] The thickness of the composite solid electrolyte film containing ethyl acrylate chloroethyl ether prepared in step two is 150 μm.
[0063] The polyethyl acrylate chloroethyl ether mentioned in step 1, ④, was purchased from Zeon Corporation of Japan, model Nipol@AR71, with the structural formula (CHCH2COOR). m (CH2CHX) n In the formula: R can be a main monomer such as alkyl or ethyl, X can be -COOH, -OCOCH2Cl, OCH2CH2Cl, etc., and the average degree of polymerization of the monomer unit is represented by m and n.
[0064] Example 2: This example differs from Example 1 in that: in step 1, 0.069g of polyethyl acrylate chloroethyl ether is added to the LLZTO / PEO-LiTFSI solution; the mass percentage of polyethyl acrylate chloroethyl ether in the composite solid electrolyte membrane containing polyethyl acrylate chloroethyl ether is 4%. Everything else is the same as in Example 1.
[0065] Example 3: This example differs from Example 1 in that: in step 1, 0.106g of polyethyl acrylate chloroethyl ether is added to the LLZTO / PEO-LiTFSI solution; the mass percentage of polyethyl acrylate chloroethyl ether in the composite solid electrolyte membrane containing polyethyl acrylate chloroethyl ether is 6%. Everything else is the same as in Example 1.
[0066] Example 4: This example differs from Example 1 in that: in step 1, 0.144g of polyethyl acrylate chloroethyl ether is added to the LLZTO / PEO-LiTFSI solution; the mass percentage of polyethyl acrylate chloroethyl ether in the composite solid electrolyte membrane containing polyethyl acrylate chloroethyl ether is 8%. Everything else is the same as in Example 1.
[0067] Comparative Experiment 1: The difference between this comparative experiment and Example 1 is that in step 1, ① 1g of polyethylene oxide and 0.407g of lithium bis(trifluoromethanesulfonyl)imide were added to 14mL of acetonitrile solution, and heated and stirred for 8h at a temperature of 50℃ and a stirring speed of 450r / min until the polyethylene oxide was completely dissolved, thus obtaining a PEO-LiTFSI solution.
[0068] The polyethylene oxide mentioned is pretreated polyethylene oxide, and the pretreatment specifically involves drying at a temperature of 50°C for 6 hours.
[0069] ② Add 0.074 g of lithium lanthanum zirconium tantalum oxide to 2 mL of acetonitrile solution, and sonicate for 2 h at room temperature and ultrasonic power of 15 W / L until uniformly dispersed to obtain LLZTO suspension.
[0070] The particle size of the lithium lanthanum zirconium tantalum oxide is 5μm~8μm;
[0071] ③ The LLZTO suspension was added to the PEO-LiTFSI solution, and the mixture was heated and stirred for 8 hours at 50°C and a stirring speed of 540 r / min to obtain the LLZTO / PEO-LiTFSI solution; Step 2 prepared the LLZTO / PEO-LiTFSI composite solid electrolyte film (LLZTO / PEO-LiTFSI film), and the mass percentage of LLZTO in the LLZTO / PEO-LiTFSI composite solid electrolyte film was 5%. Other steps were the same as in Example 1.
[0072] Comparative Experiment 2: This comparative experiment differs from Comparative Experiment 1 in that: in step 1, ②, 0.156g of lithium lanthanum zirconium tantalum oxide was added to 2mL of acetonitrile solution; and in step 2, the mass percentage of LLZTO in the LLZTO / PEO-LiTFSI composite solid electrolyte film was 10%. Everything else was the same as in Example 1.
[0073] Comparative Experiment 3: This comparative experiment differs from Comparative Experiment 1 in that: in step 1, ②, 0.248g of lithium lanthanum zirconium tantalum oxide was added to 2mL of acetonitrile solution; and the mass percentage of LLZTO in the LLZTO / PEO-LiTFSI composite solid electrolyte film prepared in step 2 was 15%. All other steps were the same as in Example 1.
[0074] Comparative Experiment 4: This comparative experiment differs from Comparative Experiment 1 in that: in step 1, ②, 0.352g of lithium lanthanum zirconium tantalum oxide was added to 2mL of acetonitrile solution; and the mass percentage of LLZTO in the LLZTO / PEO-LiTFSI composite solid electrolyte film prepared in step 2 was 20%. All other aspects are the same as in Example 1.
[0075] Comparative Experiment 5: This comparative experiment differs from Comparative Experiment 1 in that steps ② and ③ of step 1 are omitted; the mass percentage of LLZTO in the LLZTO / PEO-LiTFSI composite solid electrolyte film prepared in step 2 is 0%. Everything else is the same as in Example 1.
[0076] Figure 1 The surface scanning electron microscope (SEM) image of the LLZTO / PEO-LiTFSI film prepared in Experiment 3 is shown in the figure for comparison. As can be seen, there is severe agglomeration of ceramic particles.
[0077] Figure 2 The image shows a scanning electron microscope (SEM) image of the DE / LLZTO / PEO-LiTFSI film prepared in Example 3. As shown in the figure, the agglomeration of ceramic particles has been significantly eliminated and the particles are uniformly distributed on the surface of the film, indicating that DE improves the dispersion of LLZTO particles in PEO.
[0078] Figure 3To compare the ionic conductivity of LLZTO / PEO-LiTFSI membranes with different LLZTO additions in Experiments 1-5 and DE / LLZTO / PEO-LiTFSI membranes with different DE additions in Examples 1-4 at 60°C, the figure shows that the ionic conductivity is 0.197 mS / cm when the mass fraction of LLZTO is 0%. As the mass fraction of LLZTO increases, the ionic conductivity of the LLZTO / PEO-LiTFSI electrolyte membrane shows a trend of first increasing and then decreasing, reaching a maximum of 0.375 mS / cm when the mass fraction of LLZTO is 15%. Similarly, as the mass fraction of DE increases, the ionic conductivity of the DE / LLZTO / PEO-LiTFSI membrane shows a trend of first increasing and then decreasing, reaching a maximum of 0.765 mS / cm when the mass fraction of DE is 4%, and a maximum of 0.810 mS / cm when the mass fraction of DE is 6%. Compared to LLZTO / PEO-LiTFSI membranes, electrolyte membranes with 4%~6% by mass of ethyl chloroethyl acrylate have at least 100% higher ionic conductivity.
[0079] Figure 4 The figure shows the electrochemical impedance spectroscopy of stainless steel symmetric cells assembled using LLZTO / PEO-LiTFSI membranes with different LLZTO addition amounts in comparative experiments one through five at 60 °C. As shown in the figure, with the increase of LLZTO mass fraction, the bulk resistance of the electrolyte membrane first decreases and then increases, reaching a minimum of 16 Ω when the LLZTO mass fraction is 15%.
[0080] Figure 5 The electrochemical impedance spectroscopy (EIS) spectra of stainless steel symmetric cells assembled using DE / LLZTO / PEO-LiTFSI membranes with different DE addition amounts from Examples 1 to 4 are shown at 60°C. As the mass fraction of DE increases, the bulk resistance of the electrolyte membrane first decreases and then increases, reaching a minimum of 2.2 Ω when the mass fraction of DE is 6%. Compared to the LLZTO / PEO-LiTFSI membrane, the electrolyte membrane with added ethyl chloroethylene acrylate (ECE) showed a reduction in bulk resistance of at least 50% at different DE addition amounts.
[0081] Figure 6 The lithium-ion symmetric battery assembled using the LLZTO / PEO-LiTFSI film prepared in Comparative Experiment 3 and the lithium-ion symmetric battery assembled using the DE / LLZTO / PEO-LiTFSI film prepared in Example 3 both showed a current density of 0.1 mA / cm² at 60°C. 2The constant current density long-cycle test results are shown in the figures. Figure a shows a Li|LLZTO / PEO-LiTFSI|Li symmetric cell, and figure b shows a Li|DE / LLZTO / PEO-LiTFSI|Li symmetric cell. As shown, due to the addition of DE, the polarization voltage of the electrolyte membrane decreased from 0.11V to 0.08V, and the cycle life of the electrolyte membrane increased from 686 h to 2522 h. This indicates that DE can reduce the interfacial resistance of the electrolyte, improve the interfacial compatibility between the electrolyte membrane and lithium metal, and make it more compatible with the lithium anode. + Deposition and stripping are more stable. In addition, compared with LLZTO / PEO-LiTFSI membranes, the electrolyte membrane with added ethyl chloroethylene acrylate has a cycle life that is at least 3.5 times longer, which can significantly extend the cycle performance of the electrolyte membrane.
[0082] Figure 7 The figures show the limiting current density tests at 60°C for a lithium-ion symmetric battery assembled using the LLZTO / PEO-LiTFSI film prepared in Comparative Experiment 3 and a lithium-ion symmetric battery assembled using the DE / LLZTO / PEO-LiTFSI film prepared in Example 3. Figure a shows the Li|LLZTO / PEO-LiTFSI|Li symmetric battery, and figure b shows the Li|DE / LLZTO / PEO-LiTFSI|Li symmetric battery. As shown in the figures, due to the addition of DE, the maximum current density that the electrolyte membrane can withstand increases from 0.55 mA / cm². 2 Increased to 1.50 mA / cm 2 This indicates that DE can increase the limiting current density of the electrolyte, enabling it to operate under higher current density conditions.
[0083] Figure 8The graphs show the rate performance of the full cells assembled using the LLZTO / PEO-LiTFSI film prepared in Comparative Experiment 3 and the full cells assembled using the DE / LLZTO / PEO-LiTFSI film prepared in Example 3 at 60°C. ■ represents the specific capacity of the Li|LLZTO / PEO-LiTFSI|LFP full cell, ● represents the specific capacity of the Li|DE / LLZTO / PEO-LiTFSI|LFP full cell, ▲ represents the coulombic efficiency of the Li|LLZTO / PEO-LiTFSI|LFP full cell, and ▼ represents the coulombic efficiency of the Li|DE / LLZTO / PEO-LiTFSI|LFP full cell. In the assembly of the full cells, the positive electrode slurry was prepared by weighing dried lithium iron phosphate (LFP), carbon black, and polyvinylidene fluoride (PVDF) in a mass ratio of 8:1:1, grinding for 30 min to mix the components evenly, and then adding the black mixture to N-methyl-2-pyrrolidone (NMP) solvent and stirring magnetically for 6 h. As shown in the figure, due to the addition of DE, the discharge specific capacity of the electrolyte membrane at 1C rate increased from 46.27 mAh / g to 137.94 mAh / g, and the coulombic efficiency increased from 93.71% to 98.28%. This indicates that DE can improve the charge and discharge performance of the electrolyte at high rates, enabling it to operate under higher rate conditions.
Claims
1. A method for preparing a composite solid electrolyte film containing ethyl polyacrylate chloroethyl ether, characterized in that... It is done in the following steps: I. Preparation of LLZTO / PEO-LiTFSI solution containing polyethyl acrylate chloroethyl ether: ① Add polyethylene oxide and lithium bis(trifluoromethanesulfonyl)imide to an acetonitrile solution and heat and stir until the polyethylene oxide is completely dissolved to obtain a PEO-LiTFSI solution; ② Add lithium lanthanum zirconium tantalum oxide to acetonitrile solution and sonicate at room temperature until uniformly dispersed to obtain LLZTO suspension; ③ Add the LLZTO suspension to the PEO-LiTFSI solution and heat and stir to obtain the LLZTO / PEO-LiTFSI solution; ④ Add ethyl acrylate chloroethyl ether to the LLZTO / PEO-LiTFSI solution and heat and stir until the ethyl acrylate chloroethyl ether is completely dissolved to obtain the DE / LLZTO / PEO-LiTFSI solution; II. Preparation of composite solid electrolyte films containing polyethyl acrylate chloroethyl ether: Inside the glove box, the DE / LLZTO / PEO-LiTFSI solution was cast into a film, then dried and hot-pressed to obtain a composite solid electrolyte film containing ethyl acrylate chloroethyl ether. The mass percentage of polyethyl acrylate chloroethyl ether in the composite solid electrolyte film containing polyethyl acrylate chloroethyl ether is 2% to 8%.
2. The method for preparing a composite solid electrolyte film containing ethyl polyacrylate chloroethyl ether according to claim 1, characterized in that... In step 1①, the total mass ratio of polyethylene oxide and lithium bis(trifluoromethanesulfonyl)imide to the volume ratio of the acetonitrile solution is 1 g:(10~12) mL; the polyethylene oxide mentioned in step 1① is pretreated polyethylene oxide, and the pretreatment specifically involves drying at a temperature of 50℃~60℃ for 5h~6h; in step 1①, polyethylene oxide and lithium bis(trifluoromethanesulfonyl)imide are added to the acetonitrile solution, and heated and stirred at a temperature of 50℃~60℃ and a stirring speed of 300r / min~450r / min for 6h~8h until the polyethylene oxide is completely dissolved.
3. The method for preparing a composite solid electrolyte film containing ethyl polyacrylate chloroethyl ether according to claim 1, characterized in that... The mass ratio of lithium lanthanum zirconium tantalum oxide to acetonitrile solution in step 1 and 2 is 1 g: (8~10) mL; the particle size of lithium lanthanum zirconium tantalum oxide in step 1 and 2 is 5 μm~8 μm; in step 1 and 2, lithium lanthanum zirconium tantalum oxide is added to acetonitrile solution and ultrasonically stirred for 30 min~45 min until uniformly dispersed at room temperature and ultrasonic power of 10 W / L~20 W / L.
4. The method for preparing a composite solid electrolyte film containing ethyl polyacrylate chloroethyl ether according to claim 1, characterized in that... In step 1, the mass ratio of polyethylene oxide to lithium bis(trifluoromethanesulfonyl)imide in the LLZTO / PEO-LiTFSI solution is 1:(0.362~0.407); the mass ratio of polyethylene oxide to lithium lanthanum zirconium tantalum oxide in the LLZTO / PEO-LiTFSI solution is 1:(0.074~0.352); in step 1, the LLZTO suspension is added to the PEO-LiTFSI solution, and the mixture is heated and stirred for 6h~8h at a temperature of 50℃~60℃ and a stirring speed of 450r / min~600r / min.
5. The method for preparing a composite solid electrolyte film containing ethyl polyacrylate chloroethyl ether according to claim 1, characterized in that... In step 1, ④, polyethyl acrylate chloroethyl ether is added to the LLZTO / PEO-LiTFSI solution and heated and stirred for 24h to 48h at a temperature of 50℃~60℃ and a stirring speed of 450r / min~600r / min until the polyethyl acrylate chloroethyl ether is completely dissolved.
6. The method for preparing a composite solid electrolyte film containing ethyl polyacrylate chloroethyl ether according to claim 1, characterized in that... In step two, the DE / LLZTO / PEO-LiTFSI solution is placed in the transition chamber of a glove box and evacuated for 10-20 minutes. Then, it is transferred to the glove box and uniformly poured onto a polytetrafluoroethylene mold. It is dried at room temperature in the glove box for 12-24 hours. After that, it is removed from the glove box and first placed in a forced-air oven at 50-60°C for 12-24 hours, and then placed in a vacuum oven at 50-60°C for 12-24 hours. After drying, the film is hot-pressed in a hot rolling mill at 45-55°C. The water and oxygen content in the glove box is <0.01 ppm.
7. The method for preparing a composite solid electrolyte film containing ethyl polyacrylate chloroethyl ether according to claim 6, characterized in that... The polytetrafluoroethylene mold contains a layer of plastic sheet; during hot pressing in the hot roll mill, the film is sandwiched between the two plastic sheets.
8. The method for preparing a composite solid electrolyte film containing ethyl polyacrylate chloroethyl ether according to claim 7, characterized in that... The polytetrafluoroethylene mold and plastic sheet are pre-treated, and the pretreatment is carried out in the following steps: first, wash with deionized water 1 to 3 times, then rinse with anhydrous ethanol 1 to 2 times, then wipe clean with non-woven cloth, and finally dry at 50℃ to 60℃ for 20 min to 30 min.
9. The method for preparing a composite solid electrolyte film containing ethyl polyacrylate chloroethyl ether according to claim 1, characterized in that... The thickness of the composite solid electrolyte film containing ethyl acrylate chloroethyl ether prepared in step two is 100 μm to 200 μm.
10. The application of a composite solid electrolyte film containing polyethyl acrylate chloroethyl ether prepared according to claim 1, characterized in that... It is used in all-solid-state lithium metal batteries.