A purple phosphorene modified acrylic-based solid electrolyte membrane and a preparation method thereof
By modifying the acrylic-based solid electrolyte membrane with phosphorus phosphate, the problems of low ionic conductivity, insufficient lithium salt dissociation ability and poor interface stability in the existing technology have been solved, realizing a solid-state lithium battery with high safety and good electrochemical performance.
Patent Information
- Application Number
- CN202610858444.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-06-15
- Publication Date
- 2026-08-25
AI Technical Summary
Existing acrylic-based solid electrolytes suffer from low ionic conductivity, insufficient lithium salt dissociation capacity, poor interface stability, and are prone to inducing lithium dendrite growth, which affect the safety and lifespan of solid-state lithium batteries.
An acrylic-based solid electrolyte membrane modified with phosphorus phosphate was used. By introducing phosphorus phosphate, lithium salt, ionic liquid and thermal initiator, a fast ion transport channel was constructed, which improved the stability of the electrolyte/electrode interface, suppressed lithium dendrite growth and improved electrochemical performance and safety performance.
It improves the ion conduction performance of solid electrolytes, enhances the rate performance and cycle stability of batteries, optimizes the interfacial contact between electrolytes and electrodes, and improves the interfacial stability and safety of solid lithium batteries.
Smart Images
Figure CN122638573A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of solid-state lithium battery technology, and in particular to a phosphorus-modified acrylic-based solid electrolyte membrane and its preparation method. Background Technology
[0002] With the rapid development of portable electronic devices, electric vehicles, and large-scale energy storage systems, lithium batteries have been widely used due to their high energy density and good cycle performance. However, most traditional lithium batteries use organic liquid electrolytes, which have problems such as flammability, leakage, and poor thermal stability. They are prone to thermal runaway under overcharging, short circuit, or high temperature conditions, making it difficult to meet the development requirements of high-safety energy storage devices. Therefore, developing solid-state electrolytes with high safety and good electrochemical performance has become an important research direction in the field of solid-state lithium batteries.
[0003] Solid-state electrolytes typically include inorganic solid-state electrolytes, polymer solid-state electrolytes, and composite solid-state electrolytes. Among them, polymer solid-state electrolytes have attracted widespread attention due to their advantages such as good flexibility, ease of processing into films, and good contact with the electrode interface. In particular, acrylic polymer systems have good designability, polymerizability, and film-forming properties, showing promising application prospects in solid-state lithium batteries. However, existing acrylic-based solid-state electrolytes still generally suffer from problems such as low room-temperature ionic conductivity, limited lithium salt dissociation ability, and discontinuous lithium-ion migration channels, resulting in significant battery polarization, poor rate performance, and affecting cycle stability.
[0004] Furthermore, in lithium metal anode systems, the stability of the solid electrolyte-electrode interface significantly impacts battery performance. Existing polymer solid electrolytes are prone to localized current density concentrations during charge and discharge due to uneven ion transport, inducing lithium dendrite growth and subsequently causing interfacial instability or even internal short circuits, severely limiting the safety and lifespan of solid-state lithium batteries. To address these issues, current technologies typically modify polymer electrolytes by adding inorganic fillers, plasticizers, or ionic liquids. However, these methods still suffer from shortcomings such as insufficient filler dispersion, limited interfacial compatibility, and minimal overall performance improvement.
[0005] Therefore, how to provide a solid electrolyte material that has high ion conductivity, good interface stability, suppression of lithium dendrites, and excellent overall safety has become a technical problem that urgently needs to be solved in this field. To this end, a phosphorus-modified acrylic-based solid electrolyte membrane and its preparation method are designed to provide a technical solution to the above-mentioned technical problem. Summary of the Invention
[0006] Therefore, it is necessary to provide a phosphorus-modified acrylic-based solid electrolyte membrane and its preparation method to address the above-mentioned technical problems, thereby solving the technical problems of low ionic conductivity, insufficient lithium salt dissociation ability, poor interface stability, and easy induction of lithium dendrite growth in existing polymer solid electrolytes.
[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:
[0008] A phosphorus-modified acrylic-based solid electrolyte membrane, the raw materials of which include phosphorus, polymer matrix, lithium salt, ionic liquid and thermal initiator;
[0009] The polymer matrix is a fluorinated acrylate compound;
[0010] The lithium salt is lithium bis(trifluoromethanesulfonylimide);
[0011] The ionic liquid is 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt;
[0012] The thermal initiator is an azo compound.
[0013] Preferably, the phosphorus powder accounts for 0.1-0.5% of the acrylic solid electrolyte by mass; the lithium salt accounts for 30% of the acrylic solid electrolyte by mass; the ionic liquid accounts for 20% of the acrylic solid electrolyte by mass; and the thermal initiator accounts for 0.3-0.5% of the acrylic solid electrolyte by mass.
[0014] Preferably, the polymer matrix is butyl hexafluoroacrylate monomer solution, and the thermal initiator is azobisisobutyronitrile.
[0015] A method for preparing a phosphorus-modified acrylic-based solid electrolyte membrane, comprising the following steps:
[0016] A. Under an inert atmosphere, lithium salt and ionic liquid are first mixed to obtain a lithium salt solution;
[0017] B. The thermal initiator and butyl hexafluoroacrylate monomer solution are ultrasonically dispersed and then mixed in a second stage to obtain a polymer solution.
[0018] C. The lithium salt solution, polymer solution, and few-layer stabilized phosphane powder are mixed in a third step and heated in a first step to obtain a phosphane-based solid electrolyte precursor solution.
[0019] D. The phosphorus-based solid electrolyte precursor solution is coated onto the positive electrode layer and placed in a vacuum drying oven for a second heating and a third heating to obtain a phosphorus-modified acrylic solid electrolyte membrane.
[0020] Preferably, in step A, the first mixing time is 5-6 hours and the temperature is 50°C;
[0021] In step B, the second mixed ultrasonic power is 100W, the temperature is 15℃, and the time is 3min;
[0022] In step C, the third mixing time is 5-10 min, the rotation speed is 100 rpm, and the temperature is 30°C; the first heating rotation speed is 150 rpm, the temperature is 75°C, and the time is 5-8 min.
[0023] In step D, the second heating temperature is 75-85℃ and the time is 4 hours; the third heating temperature is 85℃ and the time is 8 hours.
[0024] Preferably, the thickness of the electrolyte membrane is 80-100 µm.
[0025] The preparation method of purple phosphorene powder includes the following steps:
[0026] Step 1) Grind the blocky purple phosphorus into micron-sized purple phosphorus powder in a glove box, and place the micron-sized purple phosphorus powder in N-methylpyrrolidone solvent to obtain a purple phosphorus dispersion;
[0027] Step 2) The purple phosphorus dispersion obtained in step 1) is subjected to cell disruption and ultrasonic exfoliation in an ice bath, followed by fractionation and centrifugation to obtain purple phosphorus precipitate;
[0028] Step 3) Freeze-dry the phosphane precipitate obtained in Step 2) to obtain few-layer stable phosphane powder.
[0029] Preferably, in step 2), the cell disruption time is 1 hour and the power is 250W; the ultrasonic ablation time is 5 hours and the power is 250W.
[0030] Step 2) involves fractionation centrifugation at a low speed of 3000 rpm for 10 min to obtain the supernatant of phosphane; followed by centrifugation at a high speed of 12000 rpm for 15 min.
[0031] The freeze-drying time for step 3) is 12 hours.
[0032] Application of phosphorus-modified acrylic-based solid electrolyte membrane in the preparation of solid-state lithium batteries.
[0033] Preferably, the solid-state lithium battery is assembled from a composite membrane obtained by combining a phosphorus-modified acrylic-based solid electrolyte membrane with a positive electrode layer and a lithium metal sheet.
[0034] It is clear without a doubt that the technical problems to be solved by the present invention can be solved by the above-described technical solutions of the present invention.
[0035] Meanwhile, through the above technical solutions, the present invention has at least the following beneficial effects:
[0036] 1. The present invention provides a phosphorus-modified acrylic-based solid electrolyte membrane and its preparation method. By introducing phosphorus, the structure and surface electronic properties of phosphorus are used to promote the dissociation of lithium salt, construct a fast ion transport channel, and improve the stability of the electrolyte / electrode interface, thereby improving the electrochemical performance and safety performance of the solid electrolyte.
[0037] 2. This invention introduces purple phosphorus into a butyl hexafluoroacrylate-based solid electrolyte. By utilizing its surface lone pair electrons, it enhances the interaction with lithium salt, promotes lithium salt dissociation, and increases the content of free lithium ions in the system, thereby improving the ion conduction performance of the solid electrolyte.
[0038] 3. The purple phosphorusene of the present invention has a two-dimensional layered structure, which can construct relatively continuous lithium-ion migration channels inside the electrolyte, shorten the ion transport path, reduce ion migration resistance, and thus improve the rate performance and cycle stability of the battery.
[0039] 4. The phosphorus-modified solid electrolyte prepared by this invention can optimize the interfacial contact between the electrolyte and the electrode, alleviate interfacial side reactions, and inhibit the formation and growth of lithium dendrites to a certain extent, which helps to improve the interfacial stability and safety of solid lithium batteries.
[0040] 5. This invention uses fluorinated acrylate compounds as polymer matrix and combines lithium salt, ionic liquid and thermal initiator to construct a composite system. The resulting composite solid electrolyte has good film-forming properties, flexibility, electrochemical stability and thermal safety, and is suitable for widespread application in high-safety solid lithium batteries. Attached Figure Description
[0041] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0042] Figure 1 This is a TEM image of phosphane provided in Example 3 of the present invention;
[0043] Figure 2 These are mechanical property diagrams for Embodiments 3-5 and Comparative Example 1 of the present invention;
[0044] Figure 3 The electrochemical impedance spectroscopy diagrams for Examples 3-5 and Comparative Example 1 of this invention are shown below.
[0045] Figure 4 The diagram shows the cycle performance of Embodiments 3-5 and Comparative Example 1 of the present invention;
[0046] Figure 5 This is a schematic diagram of the raw materials for the phosphorus-modified acrylic-based solid electrolyte membrane of the present invention. Detailed Implementation
[0047] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.
[0048] To enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.
[0049] It should be noted that, unless otherwise specified, the embodiments and features and technical solutions in the present invention can be combined with each other.
[0050] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.
[0051] Example 1
[0052] refer to Figure 5 A phosphorus-modified acrylic-based solid electrolyte membrane, the raw materials of which include phosphorus, polymer matrix, lithium salt, ionic liquid and thermal initiator;
[0053] The mass percentage of phosphorus phosphate in the acrylic solid electrolyte is 0.1-0.5%; the mass percentage of lithium salt in the acrylic solid electrolyte is 30%; the mass percentage of ionic liquid in the acrylic solid electrolyte is 20%; and the mass percentage of thermal initiator in the acrylic solid electrolyte is 0.3-0.5%.
[0054] The polymer matrix is a fluorinated acrylate compound, specifically a butyl hexafluoroacrylate monomer solution;
[0055] The lithium salt is lithium bis(trifluoromethanesulfonyl)imide;
[0056] The ionic liquid is 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt;
[0057] The thermal initiator is an azo compound, specifically azobisisobutyronitrile.
[0058] Example 2
[0059] Based on Example 1 above, a method for preparing a phosphorus-modified acrylic-based solid electrolyte membrane is disclosed, the steps of which are as follows:
[0060] A. Under an inert atmosphere, lithium salt and ionic liquid are first mixed to obtain a lithium salt solution;
[0061] Preferably, in step A, the mass ratio of lithium salt and ionic liquid to polymer matrix is 30% and 20%, respectively; the first mixing time is 5-6 hours, and the temperature is 50°C.
[0062] B. The thermal initiator and butyl hexafluoroacrylate monomer solution are ultrasonically dispersed and then mixed in a second stage to obtain a polymer solution.
[0063] Preferably, in step B, the mass ratio of the thermal initiator, which is azobisisobutyronitrile, to the polymer matrix, which is butyl hexafluoroacrylate monomer solution, is 0.3-0.5%; the ultrasonic power of the second mixture is 100W, the temperature is 15℃, and the time is 3min.
[0064] C performs a third mixing and a first heating of lithium salt solution, polymer solution and few-layer stabilized phosphane powder to obtain a phosphane-based solid electrolyte precursor solution.
[0065] Preferably, in step C, the mass ratio of phosphane powder and lithium salt solution to butyl hexafluoroacrylate monomer solution is 0.1-0.5%; the third mixing time is 5-10 min, the rotation speed is 100 rpm, and the temperature is 30°C; the first heating speed is 150 rpm, the temperature is 75°C, and the time is 5-8 min.
[0066] D. The precursor solution of phosphorus-based solid electrolyte was coated onto the positive electrode layer and placed in a vacuum drying oven for a second and a third heating to obtain a phosphorus-modified acrylic solid electrolyte membrane.
[0067] Preferably, the electrolyte membrane thickness is 80-100 µm.
[0068] Preferably, in step D, the second heating temperature is 75-85℃ and the time is 4 hours; the third heating temperature is 85℃ and the time is 8 hours.
[0069] Specifically, the second heating temperature is 75℃, and the time is 4 hours.
[0070] In this embodiment, the preparation method of purple phosphorene powder includes the following steps:
[0071] 1) Grind the blocky purple phosphorus into micron-sized powder in a glove box, and place the micron-sized purple phosphorus powder in N-methylpyrrolidone solvent to obtain a purple phosphorus dispersion;
[0072] Preferably, the concentration of the purple phosphorus dispersion in step 1) is 0.1-0.5 g / mL.
[0073] 2) The purple phosphorus dispersion obtained in step 1) was subjected to cell disruption and ultrasonic exfoliation in an ice bath, followed by fractionation and centrifugation to obtain purple phosphorus precipitate;
[0074] Preferably, in step 2), the cell pulverization time is 1 hour and the power is 250W; the ultrasonic peeling time is 5 hours and the power is 250W; the fractionation centrifugation in step 2) is performed at a low speed of 3000 rpm for 10 minutes to obtain the supernatant of phosphatidylcholine; and at a high speed of 12000 rpm for 15 minutes.
[0075] 3) Freeze-dry the phosphane precipitate obtained in step 2) above to obtain few-layer stable phosphane powder.
[0076] Preferably, the freeze-drying time in step 3) is 12 hours.
[0077] Example 3
[0078] Based on Example 1 above, a method for preparing a phosphorus-modified acrylic-based solid electrolyte membrane is disclosed, comprising the following steps:
[0079] 1) In a glove box, weigh lithium bis(trifluoromethanesulfonyl)imide and 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, add them to the reaction vessel at a ratio of 30% and 20% relative to the mass ratio of butyl hexafluoroacrylate monomer solution, and stir and mix at 50°C for 5 hours to obtain a lithium salt solution.
[0080] 2) Take butyl hexafluoroacrylate monomer solution as the polymer matrix monomer, add azobisisobutyronitrile to it, the mass ratio of azobisisobutyronitrile to butyl hexafluoroacrylate monomer solution is 0.4%; place it under ultrasonic conditions for dispersion treatment, ultrasonic power is 100W, time is 3min, to obtain polymer solution.
[0081] 3) Mix the lithium salt solution with the polymer solution, and then add the few-layer stabilized phosphane powder. The mass ratio of the phosphane powder to the butyl hexafluoroacrylate monomer solution is 0.3%. Stir the mixture at 100 rpm for 5 min to ensure thorough mixing. Then, perform a first heat treatment at 75°C to obtain the phosphane-based solid electrolyte precursor solution.
[0082] 4) The above-mentioned phosphorus-based solid electrolyte precursor solution was uniformly coated on the surface of the positive electrode layer, and then placed in a vacuum drying oven for heating and curing treatment. The second heating temperature was 75℃ and the time was 4h, and the third heating temperature was 85℃ and the time was 8h. Finally, a phosphorus-modified acrylic solid electrolyte membrane with a thickness of 90μm was obtained.
[0083] The composite membrane, which was prepared by assembling the phosphorus-modified acrylic-based solid electrolyte membrane with the positive electrode layer, was then assembled with a lithium metal sheet to obtain a solid-state lithium battery. Constant current cycling tests were conducted at a current density of 0.5C (1C = 170mAh / g), the charge / discharge cutoff voltage window was set to 2.5-4.0V, and the test temperature was 30℃.
[0084] In this embodiment, a method for preparing purple phosphorene powder includes the following steps:
[0085] 1) In an argon-atmospheric glove box, grind the lumpy purple phosphorus into micron-sized purple phosphorus powder. Weigh 0.1 g of the micron-sized purple phosphorus powder and add it to N-methylpyrrolidone solvent to prepare a purple phosphorus dispersion with a concentration of 0.1 g / mL;
[0086] 2) The purple phosphorus dispersion was placed in an ice bath and subjected to cell disruption treatment for 1 hour at a power of 250W; then subjected to ultrasonic exfoliation for 5 hours at a power of 250W to promote the exfoliation and dispersion of purple phosphorus, thus obtaining a purple phosphorus dispersion.
[0087] 3) The phosphorus dispersion after cell disruption and ultrasonic exfoliation was subjected to fractional centrifugation: First, centrifuge at 3000 rpm for 10 min and take the supernatant; then centrifuge the supernatant at 12000 rpm for 15 min to obtain phosphorus precipitate.
[0088] 4) Wash the phosphorus precipitate with anhydrous ethanol 3-4 times to remove solvent residue;
[0089] 5) Freeze-dry the phosphane precipitate for 12 hours to obtain few-layer stable phosphane powder.
[0090] In this embodiment, the TEM image of the specifically prepared purple phosphorene is as follows: Figure 1 .
[0091] Example 4
[0092] Based on Example 1 above, a method for preparing a phosphorus-modified acrylic-based solid electrolyte membrane is disclosed, comprising the following steps:
[0093] 1) In a glove box, weigh lithium bis(trifluoromethanesulfonyl)imide and 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, add them to the reaction vessel at a ratio of 30% and 20% relative to the mass ratio of butyl hexafluoroacrylate monomer solution, and stir and mix at 50°C for 5 hours to obtain a lithium salt solution.
[0094] 2) Take butyl hexafluoroacrylate monomer solution as the polymer matrix monomer, add azobisisobutyronitrile to it, the mass ratio of azobisisobutyronitrile to butyl hexafluoroacrylate monomer solution is 0.4%; place it under ultrasonic conditions for dispersion treatment, ultrasonic power is 100W, time is 3min, to obtain polymer solution.
[0095] 3) Mix the lithium salt solution with the polymer solution, and then add the few-layer stabilized phosphane powder. The mass ratio of phosphane to butyl hexafluoroacrylate monomer solution is 0.3%. Stir the mixture at 100 rpm for 5 min to ensure thorough mixing; then perform a first heat treatment at 75 °C to obtain the phosphane-based solid electrolyte precursor solution.
[0096] 4) The above-mentioned phosphorus-based solid electrolyte precursor solution was uniformly coated on the surface of the positive electrode layer, and then placed in a vacuum drying oven for heating and curing treatment. The second heating temperature was 75℃ and the time was 4h, and the third heating temperature was 85℃ and the time was 8h. Finally, a phosphorus-modified acrylic solid electrolyte membrane with a thickness of 90μm was obtained.
[0097] The composite membrane, which was prepared by assembling the phosphorus-modified acrylic-based solid electrolyte membrane with the positive electrode layer, was then assembled with a lithium metal sheet to obtain a solid-state lithium battery. Constant current cycling tests were conducted at a current density of 0.5C (1C = 170mAh / g), the charge / discharge cutoff voltage window was set to 2.5-4.0V, and the test temperature was 30℃.
[0098] In this embodiment, a method for preparing purple phosphorene powder includes the following steps:
[0099] 1) In an argon-atmospheric glove box, grind the lumpy purple phosphorus into micron-sized purple phosphorus powder. Weigh 0.3g of the micron-sized purple phosphorus powder and add it to N-methylpyrrolidone solvent to prepare a purple phosphorus dispersion with a concentration of 0.3g / mL;
[0100] 2) The purple phosphorus dispersion was placed in an ice bath and subjected to cell disruption treatment for 1 hour at a power of 250W; then subjected to ultrasonic exfoliation for 5 hours at a power of 250W to promote the exfoliation and dispersion of purple phosphorus, thus obtaining a purple phosphorus dispersion.
[0101] 3) The phosphorus dispersion after cell disruption and ultrasonic exfoliation was subjected to fractional centrifugation: First, centrifuge at 3000 rpm for 10 min and take the supernatant; then centrifuge the supernatant at 12000 rpm for 15 min to obtain phosphorus precipitate.
[0102] 4) Wash the phosphorus precipitate with anhydrous ethanol 3-4 times to remove solvent residue;
[0103] 5) Freeze-dry the phosphane precipitate for 12 hours to obtain few-layer stable phosphane powder.
[0104] Example 5
[0105] Based on Example 1 above, a method for preparing a phosphorus-modified acrylic-based solid electrolyte membrane is disclosed, comprising the following steps:
[0106] 1) In a glove box, weigh lithium bis(trifluoromethanesulfonyl)imide and 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, add them to the reaction vessel at a ratio of 30% and 20% relative to the mass ratio of butyl hexafluoroacrylate monomer solution, and stir and mix at 50°C for 5 hours to obtain a lithium salt solution.
[0107] 2) Take butyl hexafluoroacrylate monomer solution as the polymer matrix monomer, add azobisisobutyronitrile to it, the mass ratio of azobisisobutyronitrile to butyl hexafluoroacrylate monomer solution is 0.4%; place it under ultrasonic conditions for dispersion treatment, ultrasonic power is 100W, time is 3min, to obtain polymer solution.
[0108] 3) Mix the lithium salt solution with the polymer solution, and then add the few-layer stabilized phosphane powder. The mass ratio of phosphane to butyl hexafluoroacrylate monomer solution is 0.3%. Stir the mixture at 100 rpm for 5 min to ensure thorough mixing; then perform a first heat treatment at 75 °C to obtain the phosphane-based solid electrolyte precursor solution.
[0109] 4) The above-mentioned phosphorus-based solid electrolyte precursor solution was uniformly coated on the surface of the positive electrode layer, and then placed in a vacuum drying oven for heating and curing treatment. The second heating temperature was 75℃ and the time was 4h, and the third heating temperature was 85℃ and the time was 8h. Finally, a phosphorus-modified acrylic solid electrolyte membrane with a thickness of 90μm was obtained.
[0110] The composite membrane, which was prepared by assembling the phosphorus-modified acrylic-based solid electrolyte membrane with the positive electrode layer, was then assembled with a lithium metal sheet to obtain a solid-state lithium battery. Constant current cycling tests were conducted at a current density of 0.5C (1C = 170mAh / g), the charge / discharge cutoff voltage window was set to 2.5-4.0V, and the test temperature was 30℃.
[0111] In this embodiment, a method for preparing purple phosphorene powder includes the following steps:
[0112] 1) In an argon-atmospheric glove box, grind the lumpy purple phosphorus into micron-sized purple phosphorus powder. Weigh 0.5g of the micron-sized purple phosphorus powder and add it to N-methylpyrrolidone solvent to prepare a purple phosphorus dispersion with a concentration of 0.5g / mL;
[0113] 2) The purple phosphorus dispersion was placed in an ice bath and subjected to cell disruption treatment for 1 hour at a power of 250W; then subjected to ultrasonic exfoliation for 5 hours at a power of 250W to promote the exfoliation and dispersion of purple phosphorus, thus obtaining a purple phosphorus dispersion.
[0114] 3) The phosphorus dispersion after cell disruption and ultrasonic exfoliation was subjected to fractional centrifugation: First, centrifuge at 3000 rpm for 10 min and take the supernatant; then centrifuge the supernatant at 12000 rpm for 15 min to obtain phosphorus precipitate.
[0115] 4) Wash the phosphorus precipitate with anhydrous ethanol 3-4 times to remove solvent residue;
[0116] 5) Freeze-dry the phosphane precipitate for 12 hours to obtain few-layer stable phosphane powder.
[0117] Comparative Example 1
[0118] The difference from Example 3 is that no purple phosphorus powder is added, as shown in Table 1.
[0119] Table 1: Electrochemical and battery performance of Examples 3-5 and Comparative Example 1
[0120] test sample EIS (Ω) Initial discharge specific capacity (mAh / g) Ionic conductivity (mS / cm) Example 3 7.75 142.7 0.578 Example 4 4.09 158.9 1.094 Example 5 4.99 152.6 0.896 Comparative Example 1 12.40 138.5 0.361
[0121] The mechanical property diagrams of Embodiments 3-5 and Comparative Example 1 of the present invention are shown below. Figure 2 The electrochemical impedance spectroscopy diagrams of Examples 3-5 and Comparative Example 1 of the present invention are as follows: Figure 3 The cycle performance diagrams of Embodiments 3-5 and Comparative Example 1 of the present invention are shown below. Figure 4 .
[0122] In summary, this invention utilizes phosphorus as a functional additive to prepare a phosphorus-modified acrylic-based solid electrolyte membrane. The introduction of phosphorus effectively inhibits the formation and propagation of lithium dendrites, stabilizes the SEI interface, and significantly improves the coulombic efficiency and cycle stability of solid-state lithium batteries. Cycling tests of solid-state lithium batteries show that at 0.5C, the initial discharge specific capacity of the solid-state lithium battery without phosphorus is 138.5 mAh / g, and the specific capacity rapidly decays after 67 cycles; while the solid-state lithium battery using the phosphorus-modified acrylic-based electrolyte achieves an initial discharge specific capacity of 158.9 mAh / g, accounting for 93.4% of the theoretical specific capacity, and can stably cycle for 200 cycles with a capacity retention rate of 91.2% and an average coulombic efficiency greater than 99%.
[0123] In this invention, the introduced phosphane is a few-layer two-dimensional sheet material with abundant lone pairs of electrons on its surface, which can react with Li in lithium salts. + Interaction occurs, weakening Li + Association with anions promotes lithium salt dissociation and increases the free Li + Concentration. Simultaneously, phosphorene is uniformly dispersed within the butyl hexafluoroacrylate matrix, enabling the construction of two-dimensional continuous ion migration channels within the electrolyte and the formation of a low-barrier conduction region at the phosphorene / polymer interface, thereby reducing Li... +It reduces migration resistance and improves ionic conductivity. Furthermore, phosphane can improve the mechanical properties and interfacial uniformity of electrolyte membranes, homogenizing Li. + Deposition behavior inhibits lithium dendrite growth, improving the cycle stability and safety of solid-state lithium batteries.
[0124] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.
Claims
1. A phosphorus-modified acrylic-based solid electrolyte membrane, characterized in that, The raw materials include phosphorus phosphate, polymer matrix, lithium salt, ionic liquid, and thermal initiator; The polymer matrix is a fluorinated acrylate compound; The lithium salt is lithium bis(trifluoromethanesulfonylimide); The ionic liquid is 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt; The thermal initiator is an azo compound.
2. The phosphorus-modified acrylic-based solid electrolyte membrane according to claim 1, characterized in that, The phosphorus powder accounts for 0.1-0.5% of the acrylic solid electrolyte by mass; the lithium salt accounts for 30% of the acrylic solid electrolyte by mass; the ionic liquid accounts for 20% of the acrylic solid electrolyte by mass; and the thermal initiator accounts for 0.3-0.5% of the acrylic solid electrolyte by mass.
3. The phosphorus-modified acrylic-based solid electrolyte membrane according to claim 1, characterized in that, The polymer matrix is butyl hexafluoroacrylate monomer liquid, and the thermal initiator is azobisisobutyronitrile.
4. A method for preparing a phosphorus-modified acrylic-based solid electrolyte membrane, characterized in that, The steps are as follows: A. Under an inert atmosphere, lithium salt and ionic liquid are first mixed to obtain a lithium salt solution; B. The thermal initiator and butyl hexafluoroacrylate monomer solution are ultrasonically dispersed and then mixed in a second stage to obtain a polymer solution. C. The lithium salt solution, polymer solution, and few-layer stabilized phosphane powder are mixed in a third step and heated in a first step to obtain a phosphane-based solid electrolyte precursor solution. D. The phosphorus-based solid electrolyte precursor solution is coated onto the positive electrode layer and placed in a vacuum drying oven for a second heating and a third heating to obtain a phosphorus-modified acrylic solid electrolyte membrane.
5. The method for preparing a phosphorus-modified acrylic-based solid electrolyte membrane according to claim 4, characterized in that, In step A, the first mixing time is 5-6 hours and the temperature is 50°C; In step B, the second mixed ultrasonic power is 100W, the temperature is 15℃, and the time is 3min; In step C, the third mixing time is 5-10 min, the rotation speed is 100 rpm, and the temperature is 30°C; the first heating rotation speed is 150 rpm, the temperature is 75°C, and the time is 5-8 min. In step D, the second heating temperature is 75-85℃ and the time is 4 hours; the third heating temperature is 85℃ and the time is 8 hours.
6. The method for preparing a phosphorus-modified acrylic-based solid electrolyte membrane according to claim 4, characterized in that, The thickness of the electrolyte membrane is 80-100 µm.
7. A method for preparing purple phosphorene powder, characterized in that, The steps are as follows: Step 1) Grind the blocky purple phosphorus into micron-sized purple phosphorus powder in a glove box, and place the micron-sized purple phosphorus powder in N-methylpyrrolidone solvent to obtain a purple phosphorus dispersion; Step 2) The purple phosphorus dispersion obtained in step 1) is subjected to cell disruption and ultrasonic exfoliation in an ice bath, followed by fractionation and centrifugation to obtain purple phosphorus precipitate; Step 3) Freeze-dry the phosphane precipitate obtained in Step 2) to obtain few-layer stable phosphane powder.
8. The method for preparing phosphane powder according to claim 7, characterized in that, Step 2) involves cell disruption for 1 hour at a power of 250W; ultrasonic ablation for 5 hours at a power of 250W. Step 2) involves fractionation centrifugation at a low speed of 3000 rpm for 10 min to obtain the supernatant of phosphane; followed by centrifugation at a high speed of 12000 rpm for 15 min. The freeze-drying time for step 3) is 12 hours.
9. Application of phosphorus-modified acrylic-based solid electrolyte membrane in the preparation of solid-state lithium batteries.
10. The application according to claim 9, characterized in that, The solid-state lithium battery is assembled from a composite membrane obtained by combining a phosphorus-modified acrylic-based solid electrolyte membrane with a positive electrode layer and a lithium metal sheet.