A polyol-polyester block copolymer, its mass production method and application

Abstract

This invention relates to a polyol-polyester block copolymer, its batch preparation method, and its applications. The method includes: vacuum drying of the polyol, recrystallization purification of the cyclic ester monomer in an organic solvent; reacting the pretreated polyol and cyclic ester monomer in a polymerization solvent under the action of a catalyst at 80–150°C for 12–48 hours; terminating the reaction by adding a terminator; removing the polymerization solvent by rotary evaporation; and obtaining the polyol-polyester block copolymer through dissolution-precipitation, filtration, and vacuum drying. This method can achieve a batch yield of 1 kg to 1000 kg, is suitable for combinations of various polyols and cyclic ester monomers, and is simple to operate and inexpensive. When used in solid-state batteries, the prepared polyol-polyester block copolymer can effectively inhibit polymer crystallization, improve ionic conductivity, and shield terminal hydroxyl oxidation reactions, making it suitable for high-voltage solid-state batteries operating at room temperature.

Description

Technical Field

[0001] This invention relates to the field of polymer synthesis and solid-state battery materials technology, and in particular to a polyol-polyester block copolymer and its mass production preparation method and application. Background Technology

[0002] All-solid-state batteries, by using non-flammable solid electrolytes instead of liquid electrolytes, fundamentally solve the safety issues of traditional lithium-ion batteries and have become a research hotspot for next-generation battery technology. Polymer solid electrolytes are considered one of the most promising solid electrolyte materials for practical application due to their excellent flexibility, processability, and interfacial compatibility.

[0003] Polyol-polyester block copolymers are an important class of amphiphilic biodegradable materials with broad application prospects in drug delivery, tissue engineering, and solid-state electrolytes. In the field of all-solid-state batteries, these block copolymers have been shown to effectively inhibit PEO crystallization, improve ionic conductivity, and shield terminal hydroxyl oxidation reactions, making them one of the key materials for realizing high-voltage all-solid-state batteries operating at room temperature. Representative block copolymers include methoxy polyethylene glycol-b-polylactide (mPEG-b-PLA), polyethylene glycol-b-polycaprolactone (PEG-b-PCL), and polypropylene glycol-b-polylactide (PPG-b-PLA).

[0004] Currently, the main method for synthesizing polyol-polyester block copolymers is ring-opening polymerization, using polyols as macromolecular initiators to initiate the ring-opening polymerization of cyclic ester monomers in the presence of a catalyst. However, existing preparation methods have the following technical drawbacks: (1) The catalyst selection is limited, mainly using stannous octate (Sn(Oct)2). Although the catalytic efficiency is high, tin catalysts have potential biotoxicity and are sensitive to moisture, requiring strict anhydrous conditions. (2) The reaction time is long, usually requiring 48-72 hours, resulting in low production efficiency; (3) There are many side reactions, and transesterification and racemization reactions are prone to occur, which affects the molecular weight distribution and stereoregularity of the product; (4) The purification process is complicated, and it is difficult to completely remove residual catalysts and unreacted monomers; (5) There is a lack of suitable mass production preparation schemes for industrial production, and existing research is mostly limited to small-batch synthesis in the laboratory; (6) Existing methods are mostly for single block copolymer systems and lack universal preparation methods applicable to a variety of polyols and a variety of cyclic ester monomers.

[0005] Therefore, developing a method for preparing polyol-polyester block copolymers with high catalytic efficiency, mild reaction conditions, few byproducts, suitability for mass production, and good system universality is of great significance for promoting the industrial application of this material in all-solid-state batteries. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of existing methods for preparing polyol-polyester block copolymers, such as low catalyst efficiency, long reaction time, numerous by-products, difficulty in mass production, and poor system universality, by providing a method for the mass production of polyol-polyester block copolymers and their applications.

[0007] This invention provides a method for the mass production of polyol-polyester block copolymers. Through systematic screening of various catalysts and comparison of their catalytic efficiency, suitable reaction temperature, yield, and byproduct characteristics, TBD was determined to be the optimal catalyst. Simultaneously, the reaction conditions, purification method, and drying process were optimized, enabling kilogram- to ton-scale mass production of polyol-polyester block copolymers. This method is applicable to combinations of various polyols and cyclic ester monomers, exhibiting good system versatility.

[0008] To achieve the above objectives, in a first aspect, the present invention provides a method for the mass production of polyol-polyester block copolymers, the mass production method comprising: Step S1, raw material pretreatment, includes: subjecting the polyol to a first vacuum drying to remove residual water and obtain a pretreated polyol; and recrystallizing and purifying the cyclic ester monomer in a first organic solvent, followed by a second vacuum drying to obtain the pretreated cyclic ester monomer. Step S2, polymerization reaction, includes: adding the pretreated polyol, the pretreated cyclic ester monomer and polymerization solvent into a reaction device, then adding a catalyst, and heating and stirring under inert gas protection to cause the pretreated polyol and the pretreated cyclic ester monomer to undergo a polymerization reaction; wherein the heating and stirring temperature is 80℃~150℃, and the heating and stirring time is 12 hours~48 hours; Step S3, terminating the reaction, includes: adding a terminator to the reaction vessel, continuing to stir, terminating the polymerization reaction, and obtaining a reaction solution; Step S4, purification, includes: placing the reaction solution in a rotary evaporator for rotary evaporation to remove the polymerization solvent, then placing it in a dissolution-precipitation apparatus for dissolution with a second organic solvent, then adding a precipitant for precipitation, filtering, and repeating the dissolution-precipitation process at least twice. Step S5, drying, includes: subjecting the product obtained in step S4 to a third vacuum drying to obtain a polyol-polyester block copolymer. The yield of a single batch of polyol-polyester block copolymer prepared by the mass production method is 1 kg to 1000 kg; the polyol-polyester block copolymer is used in solid-state batteries.

[0009] Preferably, the polyol comprises one or more of the following: mPEG, polyethylene glycol (PEG), mPPG, polypropylene glycol (PPG), polytetrahydrofuran ether (PTMEG), polyglycerol (PG), polyvinyl alcohol (PVA), polycaprolactone diol (PCL-diol), and polylactic acid diol (PLA-diol); the number average molecular weight of the polyol is 200 g / mol to 20000 g / mol. The cyclic ester monomers include one or more of lactide (LA), glycolide (GA), caprolactone (ε-CL), valproic acid lactone (δ-VL), butyrolactone (γ-BL), trimethylene carbonate (TMC), ethylene carbonate (EC), and propylene carbonate (PC); wherein the lactide includes one or more of L-lactide, D-lactide, and DL-lactide. The molar ratio of the pretreated polyol to the pretreated cyclic ester monomer is 1:5 to 1:100.

[0010] Preferably, the catalyst comprises one or more of the following: 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), stannous octanoate (Sn(Oct)2), triethylamine, 4-dimethylaminopyridine (DMAP), stannous dichloride (SnCl2), zinc oxide (ZnO), scandium trifluoromethanesulfonate (Sc(OTf)3), and ytterbium trifluoromethanesulfonate (Yb(OTf)3); the amount of the catalyst used is 0.1% to 2.0% of the molar amount of the cyclic ester monomer.

[0011] Preferably, the polymerization solvent includes one or more of acetonitrile, toluene, xylene, trimethylbenzene, chlorobenzene, tetrahydrofuran, dioxane, diethylene glycol dimethyl ether, N,N-dimethylformamide, N,N-dimethylacetamide, and dimethyl sulfoxide; The polymerization solvent is 0.5 to 3 times the total mass of the pretreated polyol and the pretreated cyclic ester monomer.

[0012] Preferably, the terminator includes one or more of benzoic acid, acetic acid, citric acid, phosphoric acid, or hydrochloric acid; the amount of the terminator is 1 to 5 times the molar amount of the catalyst.

[0013] Preferably, the first organic solvent includes one or more of the following: dichloromethane, chloroform, ethyl acetate, tetrahydrofuran, acetone, and N,N-dimethylformamide; The second organic solvent includes one or more of the following: dichloromethane, chloroform, ethyl acetate, tetrahydrofuran, acetone, and N,N-dimethylformamide; The precipitant includes one or more of methanol, ethanol, isopropanol, diethyl ether, petroleum ether, and n-hexane.

[0014] Preferably, the heating and stirring temperature is 100℃~120℃, and the heating and stirring time is 20 hours~28 hours.

[0015] Preferably, the temperature of the first vacuum drying is 80℃~100℃, and the vacuum drying time is 4 hours~6 hours; The second vacuum drying temperature is 40℃~50℃, and the vacuum drying time is 12 hours~24 hours; The temperature of the third vacuum drying is 40℃~60℃, and the vacuum drying time is 24 hours~48 hours; The reaction equipment includes a reaction vessel; the rotary evaporation equipment includes a rotary evaporator or a thin-film evaporator; the dissolution and precipitation equipment includes one or more of a dissolution vessel, a filtration device, a vacuum filtration device, a plate and frame filter press, or a centrifugal filter.

[0016] In a second aspect, the present invention provides a polyol-polyester block copolymer prepared by the batch preparation method described in the first aspect, wherein the polyol-polyester block copolymer comprises: methoxy polyethylene glycol-b-polylactide (mPEG-b-PLA), methoxy polyethylene glycol-b-polyglycolic acid (mPEG-b-PGA), methoxy polyethylene glycol-b-polycaprolactone (mPEG-b-PCL), methoxy polyethylene glycol-b-polytrimethylene carbonate (mPEG-b-PTMC), and poly... One or more of the following: ethylene glycol-b-polylactide (PEG-b-PLA), polyethylene glycol-b-polycaprolactone (PEG-b-PCL), polyethylene glycol-b-polyglycolic acid (PEG-b-PGA), polypropylene glycol-b-polylactide (PPG-b-PLA), polytetrahydrofuran ether-b-polylactide (PTMEG-b-PLA), polyvinyl alcohol-g-polylactide (PVA-g-PLA), and methoxy polypropylene glycol-b-polylactide (mPPG-b-PLA).

[0017] Thirdly, the present invention provides a solid-state battery, the solid-state battery comprising a positive electrode, a negative electrode and a solid electrolyte layer disposed between the positive electrode and the negative electrode, the solid electrolyte layer comprising the polyol-polyester block copolymer described in the second aspect.

[0018] The present invention provides a polyol-polyester block copolymer, its mass production preparation method and application, which has the following technical effects.

[0019] (1) The present invention provides a method for the mass production of polyol-polyester block copolymers, which employs ring-opening polymerization, using polyol as a macromolecular initiator to initiate the polymerization of cyclic ester monomers under the action of a catalyst, followed by termination, purification, and drying to obtain polyol-polyester block copolymers. This mass production method is applicable to combinations of various polyols and various cyclic ester monomers, and can prepare a series of block copolymers with different structures, exhibiting good system versatility. This mass production method uses conventional polymerization equipment, has a simple process flow, mild operating conditions, and convenient post-processing, enabling mass production from 1 kg to 1000 kg per batch, with high yield, meeting the needs of industrial production.

[0020] (2) The polyol-polyester block copolymer prepared by the batch preparation method provided by the invention has a molecular chain composed of polyol segments and polyester segments, with a clear structure and good uniformity. The introduction of polyester segments into the block copolymer can effectively suppress the crystallization behavior of polyol segments, increase the proportion of amorphous regions in the polymer, and provide more channels for ion transport. At the same time, the polyester segments shield the terminal hydroxyl groups of the polyol, reducing the oxidation side reactions of the terminal hydroxyl groups under high pressure. The copolymer has good film-forming properties and processing performance, and can be prepared into a uniform and dense self-supporting film.

[0021] (3) When the polyol-polyester block copolymer prepared by this invention is used as the matrix material of the solid electrolyte layer in a solid-state battery, it can provide ion conduction function at room temperature. In the polyol-polyester block copolymer, the polyol segments are responsible for the dissociation of lithium salt and the chain segment movement and transport of lithium ions, while the polyester segments enhance the chain segment movement ability by reducing crystallinity. The synergistic effect of the two enables the electrolyte to have ion conduction energy at room temperature. The shielding effect of the polyester segments on the terminal hydroxyl groups reduces the tendency of the electrolyte to oxidize and decompose under high voltage, and widens the working voltage window of the electrolyte, making it suitable for solid-state battery systems that match high-voltage cathode materials. The polyol-polyester block copolymer prepared by the batch preparation method provided by this invention meets the application requirements in solid-state batteries. Attached Figure Description

[0022] Figure 1 This is a flowchart of a method for the mass production of polyol-polyester block copolymers provided in this embodiment of the invention.

[0023] Figure 2 This is an example of an apparatus diagram for preparing polyol-polyester block copolymers provided in an embodiment of the present invention.

[0024] Figure 3 The molecular structure of the catalyst for ring-opening polymerization provided in the embodiments of the present invention is shown below.

[0025] Figure 4The image shows the 1H NMR spectrum of the mPEG-b-PLA block copolymer prepared in Example 1 of this invention.

[0026] Figure 5 The image shows the Fourier Transform Infrared (FTIR) spectrum of the mPEG-b-PLA block copolymer prepared in Example 1 of this invention. Detailed Implementation

[0027] 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. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0028] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0029] This invention provides a method for the mass production of polyol-polyester block copolymers for solid-state batteries, such as... Figure 1 As shown, the batch preparation method specifically includes the following steps.

[0030] Step S1 involves pretreating the polyol and cyclic ester monomer raw materials.

[0031] Specifically, the polyol is subjected to a first vacuum drying process to remove residual moisture, resulting in a pretreated polyol. The temperature of the first vacuum drying process is 80℃~100℃, and the vacuum drying time is 4 hours~6 hours.

[0032] The cyclic ester monomer was purified by recrystallization in a first organic solvent, followed by a second vacuum drying to obtain a pretreated cyclic ester monomer. The first organic solvent included one or more of dichloromethane, trichloromethane, ethyl acetate, tetrahydrofuran, acetone, and N,N-dimethylformamide. The second vacuum drying was carried out at a temperature of 40°C to 50°C for 12 to 24 hours.

[0033] The polyols include one or more of the following: mPEG, polyethylene glycol (PEG), mPPG, polypropylene glycol (PPG), polytetrahydrofuran ether (PTMEG), polyglycerol (PG), polyvinyl alcohol (PVA), polycaprolactone diol (PCL-diol), and polylactic acid diol (PLA-diol); the number average molecular weight of the polyols is 200 g / mol to 20000 g / mol.

[0034] Cyclic ester monomers include one or more of lactide (LA), glycolide (GA), caprolactone (ε-CL), valproic acid lactone (δ-VL), butyrolactone (γ-BL), trimethylene carbonate (TMC), ethylene carbonate (EC), and propylene carbonate (PC); wherein lactide includes one or more of L-lactide, D-lactide, and DL-lactide.

[0035] Step S2: The pretreated polyol and pretreated cyclic ester monomer are added to the catalyst to carry out the polymerization reaction.

[0036] Specifically, the process involves adding a pretreated polyol, a pretreated cyclic ester monomer, and a polymerization solvent into a reaction apparatus, then adding a catalyst, and heating and stirring under an inert gas atmosphere to induce a polymerization reaction between the pretreated polyol and the pretreated cyclic ester monomer. The heating and stirring temperature is 80°C–150°C, and the heating and stirring time is 12–48 hours. Preferably, the heating and stirring temperature is 100°C–120°C, and the heating and stirring time is 20–28 hours.

[0037] The molar ratio of pretreated polyol to pretreated cyclic ester monomer is 1:5 to 1:100.

[0038] The polymerization solvents include one or more of toluene, xylene, chlorobenzene, tetrahydrofuran, and dioxane; The polymerization solvent is 0.5 to 3 times the total mass of the pretreated polyol and the pretreated cyclic ester monomer.

[0039] The catalyst includes one or more of the following: 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), stannous octanoate (Sn(Oct)2), triethylamine, 4-dimethylaminopyridine (DMAP), stannous dichloride (SnCl2), zinc oxide (ZnO), scandium trifluoromethanesulfonate (Sc(OTf)3), and ytterbium trifluoromethanesulfonate (Yb(OTf)3); preferably TBD.

[0040] The amount of catalyst used is 0.1% to 2.0% of the molar amount of the cyclic ester monomer.

[0041] Step S3, terminating the reaction, includes: adding a terminator to the reactor, continuing stirring, terminating the polymerization reaction, and obtaining the reaction solution.

[0042] The terminator includes one or more of benzoic acid, acetic acid, citric acid, phosphoric acid, or hydrochloric acid; the amount of terminator used is 1 to 5 times the molar amount of the catalyst.

[0043] Continue stirring for 10 to 30 minutes.

[0044] Step S4, purification, includes: placing the reaction solution in a rotary evaporator for rotary evaporation to remove the polymerization solvent, then placing it in a dissolution-precipitation apparatus for dissolution with a second organic solvent, then adding a precipitant for precipitation, filtering, and repeating the dissolution-precipitation process at least twice.

[0045] The second organic solvent includes one or more of the following: dichloromethane, chloroform, ethyl acetate, tetrahydrofuran, acetone, and N,N-dimethylformamide.

[0046] Precipitating agents include one or more of the following: methanol, ethanol, isopropanol, diethyl ether, petroleum ether, and n-hexane.

[0047] Step S5, drying, includes: subjecting the product obtained in step S4 to a third vacuum drying to obtain a polyol-polyester block copolymer. The temperature of the third vacuum drying process is 40℃~60℃, and the vacuum drying time is 24 hours~48 hours.

[0048] The batch production of polyol-polyester block copolymers provided in the embodiments of the present invention is 1 kg to 1000 kg per batch. The batch preparation method provided by the embodiments of the present invention is applicable to the kilogram-scale preparation of various block copolymers, including: methoxy polyethylene glycol-b-polylactide (mPEG-b-PLA), methoxy polyethylene glycol-b-polyglycolic acid (mPEG-b-PGA), methoxy polyethylene glycol-b-polycaprolactone (mPEG-b-PCL), methoxy polyethylene glycol-b-polytrimethylene carbonate (mPEG-b-PTMC), and polyethylene glycol-b-polylactide. One or more of the following: (PEG-b-PLA), polyethylene glycol-b-polycaprolactone (PEG-b-PCL), polyethylene glycol-b-polyglycolic acid (PEG-b-PGA), polypropylene glycol-b-polylactide (PPG-b-PLA), polytetrahydrofuran ether-b-polylactide (PTMEG-b-PLA), polyvinyl alcohol-g-polylactide (PVA-g-PLA), and methoxy polypropylene glycol-b-polylactide (mPPG-b-PLA). Among these, polyvinyl alcohol-g-polylactide (PVA-g-PLA) is a graft copolymer.

[0049] In this invention, TBD is preferably used as the catalyst because the effects of different reaction temperatures on the polymerization reaction were tested. Within a set reaction time, as the reaction temperature gradually increased from 90℃ to 110℃, the yield increased, the molecular weight gradually increased, and the molecular weight distribution gradually narrowed. When the temperature continued to rise to 120℃, the yield no longer increased, the molecular weight distribution widened, and the product color deepened. These results indicate that the polymerization reaction is incomplete at too low a temperature, while too high a temperature easily triggers side reactions such as transesterification and racemization, affecting product quality. Considering all indicators, the optimal reaction temperature was determined to be 110℃.

[0050] After determining the optimal reaction temperature, this invention further investigated the effect of different reaction times on the polymerization reaction. At 110°C, as the reaction time increased from 12 hours to 24 hours, the yield and monomer conversion gradually increased, the molecular weight increased, and the molecular weight distribution gradually narrowed. Further extending the reaction time to 36 hours, the yield and conversion essentially ceased to increase, while the molecular weight distribution actually widened. These results indicate that insufficient reaction time leads to incomplete polymerization, while excessively long reaction times may trigger side reactions. Considering all indicators, the optimal reaction time was determined to be 24 hours.

[0051] The batch preparation method of the present invention is applicable to batch production from kilogram to ton level. The reaction equipment includes a reaction vessel; the rotary evaporation equipment includes a rotary evaporator or a thin film evaporator; the dissolution and precipitation equipment includes one or more combinations of a dissolution vessel, a filtration device, a vacuum filtration device, a plate and frame filter press, or a centrifugal filter.

[0052] This invention provides an example of equipment combinations used in a method for the mass production of polyol-polyester block copolymers, such as... Figure 2 As shown, the apparatus includes a reaction vessel, a rotary evaporator, and a filtration device. The dissolution, precipitation, and filtration processes are all carried out within the filtration device.

[0053] The equipment volume needs to be adjusted accordingly depending on the production scale. For kilogram-level production, such as a single batch output of 1kg-10kg, the reactor volume is 50L-100L, the rotary evaporator volume is 20L-50L, and the filtration device volume is 100L-200L. For hundred-kilogram-level production, such as a single batch output of 50kg-200kg, the reactor volume is 500L-1000L, the rotary evaporator volume is 200L-500L, and the filtration device volume is 1000L-2000L. For ton-level production, such as a single batch output of 500kg-1000kg, the reactor volume is 2000L-5000L, the rotary evaporator volume is 1000L-2000L, and the filtration device volume is 5000L-10000L. Under the same reaction conditions, high yields and narrow molecular weight distributions of the products can be obtained, indicating that the method can maintain good process stability even after being scaled up to the kilogram scale, and has good applicability to large-scale production.

[0054] In the mass production method of this invention, the catalyst used includes one or more of the following: 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), stannous octanoate (Sn(Oct)2), triethylamine, 4-dimethylaminopyridine (DMAP), stannous dichloride (SnCl2), zinc oxide (ZnO), scandium trifluoromethanesulfonate (Sc(OTf)3), and ytterbium trifluoromethanesulfonate (Yb(OTf)3). The specific structural formula of the catalyst is shown below. Figure 3 As shown.

[0055] 1,5,7-Triazabicyclo[4.4.0]dec-5-ene (TBD) is a bicyclic guanidine-based strong base catalyst. Its molecular structure contains two nitrogen heterocycles and a guanidine functional group, with a pKa of approximately 26, exhibiting strong basicity. The mechanism of TBD-catalyzed ring-opening polymerization is as follows: TBD activates the carbonyl group of the cyclic ester monomer through hydrogen bonding and acid-base synergistic effects, while simultaneously activating the terminal hydroxyl groups of the polyol, promoting nucleophilic attack and achieving efficient ring-opening polymerization. As an organic catalyst, TBD does not contain metal ions, has low biotoxicity, and is easily removed by precipitation.

[0056] Stannous octanoate (Sn(Oct)2) is currently the most commonly used ring-opening polymerization catalyst in industry. It is a light yellow oily liquid, readily soluble in organic solvents. Its catalytic mechanism is a coordination-insertion mechanism, where Sn(Oct)2 coordinates with the carbonyl group of the cyclic ester monomer, and then the terminal hydroxyl group of the polyol attacks, achieving ring-opening insertion. The advantages of Sn(Oct)2 are high catalytic efficiency and few side reactions; the disadvantage is that the tin residue has a certain degree of toxicity.

[0057] Triethylamine is a tertiary amine organic base catalyst, a colorless liquid with strong basicity. It has low catalytic efficiency, requires a long reaction time, and is prone to initiating transesterification side reactions.

[0058] 4-Dimethylaminopyridine (DMAP) is a nucleophilic catalyst. The dimethylamino group on its pyridine ring has a strong electron-donating effect, which gives it high nucleophilic catalytic activity.

[0059] Tin dichloride (SnCl2) is a Lewis acid catalyst with high catalytic efficiency, but the reaction conditions are quite harsh and require strict control of anhydrous conditions.

[0060] Zinc oxide (ZnO) is a solid base catalyst with relatively low catalytic efficiency, but it is easy to separate and recover, and has good industrial application potential. Scandium trifluoromethanesulfonate (Sc(OTf)3) and ytterbium trifluoromethanesulfonate (Yb(OTf)3) are Lewis acid catalysts with good catalytic activity and selectivity, but their high price limits their industrial application.

[0061] In the batch preparation method provided by this invention, the following types of byproducts may be generated during the polymerization process.

[0062] The first type is hydroxy acids, which are generated by residual moisture in cyclic ester monomers, which triggers the hydrolysis and ring-opening of the monomers to generate segments with hydroxyl and carboxyl groups. To address this byproduct, this invention strictly controls the moisture content of the raw materials to be below 0.01%, thereby inhibiting the hydrolysis reaction from the source.

[0063] The second category is oligomers, which are mainly produced by transesterification reactions during polymerization, resulting in a wider molecular weight distribution. By controlling the reaction temperature below 115℃ and appropriately shortening the reaction time, the transesterification reaction can be effectively suppressed, reducing the formation of oligomers.

[0064] The third category is racemic products. When the reaction temperature is too high, the lactide unit is prone to racemization, which affects the stereoregularity of the product. Controlling the reaction temperature below 115℃ can avoid the generation of this byproduct.

[0065] The fourth category consists of residual monomers, resulting from incomplete polymerization. This invention extends the reaction time to 24 hours to ensure complete monomer conversion, and then removes them through dissolution-precipitation in subsequent purification steps. Through the synergistic effect of these control measures, the formation of various byproducts can be effectively reduced, ensuring the purity and quality of the product.

[0066] The embodiments of the present invention provide a method for preparing polyol-polyester block copolymers in batches, which can be used as solid electrolyte layers and assembled together with positive and negative electrodes to form solid-state batteries.

[0067] To better understand the technical solution provided by the present invention, the following uses several specific examples to illustrate the batch preparation process and characteristics of the polyol-polyester block copolymer of the present invention.

[0068] Example 1 This embodiment provides a 100-kilogram-scale batch preparation process for polyol-polyester block copolymer (mPEG-b-PLA), as detailed below.

[0069] (1) Raw material pretreatment.

[0070] Methoxylated polyethylene glycol (mPEG2000) was added to a vacuum drying oven and vacuum dried at 80°C for 4 hours until the moisture content dropped to 0.008%. The amount of mPEG2000 used was 100 kg (50 mol).

[0071] L-lactide (L-LA) was dissolved in 200 L of ethyl acetate at 50 °C, cooled, recrystallized, filtered, and recrystallized once more. The purified L-lactide was then vacuum dried at 45 °C for 12 hours until the moisture content was reduced to 0.005%. The amount of L-LA used was 72 kg (500 mol), and the molar ratio of mPEG to LA was 1:10.

[0072] (2) Polymerization reaction.

[0073] Pretreated mPEG2000 and L-lactide were added to a 2000 L stainless steel reactor, along with 500 L of anhydrous toluene. Stirring was initiated. Nitrogen gas was purged three times to replace the air in the reactor, maintaining a positive nitrogen pressure. 1,5,7-Triazabicyclo[4.4.0]dec-5-ene (TBD) was added. The temperature was raised to 110 °C, and the reaction was stirred for 24 hours. The amount of TBD used was 348 g (2.5 mol), which is 0.5% of the molar amount of L-lactide.

[0074] (3) Terminate the reaction.

[0075] After the polymerization reaction is complete, add 305g of a toluene solution of benzoic acid with an equimolar amount of TBD, and continue stirring for 15 minutes to terminate the reaction.

[0076] (4) Purification.

[0077] The reaction solution was transferred to a rotary evaporator and toluene was removed by rotary evaporation at 60°C. Approximately 460 L of toluene was recovered and reused. The product after rotary evaporation was placed in a vacuum filtration apparatus, dissolved in 300 L of dichloromethane, and slowly added dropwise with 1200 L of cold diethyl ether to precipitate. The precipitate was collected by vacuum filtration. The precipitate was dissolved again in 200 L of dichloromethane, and 800 L of cold diethyl ether was added dropwise to precipitate. The precipitate was then collected by vacuum filtration. The above dissolution-precipitation purification steps were repeated twice.

[0078] (5) Drying.

[0079] The purified product was placed in a vacuum drying oven and dried under vacuum at 45°C for 48 hours to obtain 142 kg of white powdered mPEG-b-PLA block copolymer, with a yield of 88%.

[0080] (6) Product characterization.

[0081] The 1H NMR spectrum (¹H NMR) of the mPEG-b-PLA block copolymer prepared in this embodiment is as follows: Figure 4 As shown, the characteristic peaks for methylene protons (-CH2CH2O-) in the mPEG segment are observed at δ=3.5-3.7 ppm; the characteristic peak for methine protons (-CH(CH3)O-) in the PLA segment is at δ=5.1 ppm; and the characteristic peak for methyl protons (-CH3) in the PLA segment is at δ=1.6 ppm. The calculated integral area ratio of each characteristic peak yields a mPEG to LA segment ratio of 1:9.8, which is basically consistent with the feed ratio.

[0082] FTIR (Full-Time Infrared Spectroscopy), such as Figure 5 As shown: at approximately 3500 cm -1 The hydroxyl absorption peak at 1750 cm⁻¹ is significantly weakened, indicating that most of the terminal hydroxyl groups of mPEG participate in the polymerization reaction; -1 The characteristic absorption peak of the ester carbonyl group (C=O) appears at 1100 cm⁻¹; -1 The characteristic absorption peak of COC appears at 1750 cm⁻¹. Compared with pure mPEG, mPEG-b-PLA shows a peak at 1750 cm⁻¹. - The new peak at ¹ confirms the successful introduction of the PLA segment, while the weakening of the hydroxyl peak indicates the successful synthesis of the block copolymer.

[0083] Gel permeation chromatography (GPC) analysis showed a unimodal symmetrical distribution in the curve, with a number-average molecular weight (Mn) of 6600 g / mol, indicating that the mPEG-b-PLA prepared in this example has high purity and a narrow molecular weight distribution. Dispersion =1.18, This reflects the uniformity of molecular chain length in the polymer sample. The mPEG-b-PCL prepared in this example... The value of 1.20, close to 1.0, indicates that the chain lengths of all mPEG-b-PCL block copolymer molecules are relatively uniform, with no obvious chain transfer or transesterification side reactions. The polymerization process is well controllable, and the TBD catalyst plays an efficient and selective catalytic role. As a result, the mPEG-b-PCL prepared in this example has excellent quality and stable performance.

[0084] The preparation of a solid electrolyte membrane using the mPEG-b-PLA block copolymer prepared in this embodiment includes: reacting lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) with EO:Li + Anhydrous acetonitrile was added at a molar ratio of 10:1 and stirred at room temperature for 12 hours to obtain a homogeneous and transparent polymer electrolyte solution. This polymer electrolyte solution was uniformly cast into a polytetrafluoroethylene (PTFE) mold and allowed to stand at room temperature for 24 hours to evaporate the solvent. Then, it was transferred to a vacuum drying oven and vacuum dried at 60°C for 24 hours to obtain a solid electrolyte membrane (AEA-ASSPE-Li) with a thickness of approximately 100 μm. The membrane was cut into circular pieces with a diameter of 16 mm and placed in an argon glove box for later use.

[0085] The AEA-ASSPE-Li solid electrolyte membrane prepared in Example 1 was cut into 16 mm diameter discs and assembled with a monocrystalline NCM622 positive electrode and a 12 mm diameter lithium metal negative electrode in an argon glove box to form a CR2032 coin-type all-solid-state battery. The monocrystalline NCM622 positive electrode has a diameter of 12 mm and an active material loading of approximately 2.0 mg / cm³. 2 The Blue Battery testing system was used to conduct constant current charge-discharge tests at 30℃, with a charge-discharge rate of 0.1C and a voltage range of 2.8V to 4.3V. The test results showed that the initial discharge capacity was 152.3 mAh / g, the initial coulombic efficiency was 85.2%, the reversible capacity after 450 cycles was 105.7 mAh / g, and the capacity retention rate was 69.4%.

[0086] Example 2 This embodiment provides a kilogram-scale batch preparation process for polyol-polyester block copolymer mPEG-b-PCL, as detailed below.

[0087] (1) Raw material pretreatment.

[0088] 2.0 kg of methoxy polyethylene glycol (mPEG2000, 1.0 mol) was vacuum dried at 80 °C for 4 hours. ε-caprolactone (ε-CL) was dried overnight in anhydrous sodium sulfate and filtered. The amount of ε-CL used was 2.28 kg (20 mol), and the molar ratio of mPEG to CL was 1:20.

[0089] (2) Polymerization reaction.

[0090] Pretreated mPEG2000 and ε-CL were added to a 50 L reactor, along with 10 L of anhydrous toluene, and the mixture was purged with nitrogen for protection. TBD was then added. The mixture was heated to 110 °C and stirred for 24 hours. The amount of TBD used was 13.9 g (0.1 mol), which is 0.5% of the molar amount of ε-CL.

[0091] (3) Terminate the reaction.

[0092] Add 12.2g of benzoic acid (0.1mol) in toluene solution and stir for 15 minutes.

[0093] (4) Purification.

[0094] Toluene was removed by rotary evaporation of the reaction solution, dissolved in 6 L of dichloromethane, and precipitated by adding dropwise to 24 L of cold methanol. The precipitate was then filtered and purified twice.

[0095] (5) Drying.

[0096] The purified product was placed in a vacuum drying oven and dried under vacuum at 45°C for 48 hours to obtain 3.6 kg of white powdered mPEG-b-PCL block copolymer, with a yield of 86%.

[0097] GPC test: Mn = 14800 g / mol; =1.20, with a very narrow molecular weight distribution, and good controllability of the polymerization process.

[0098] Example 3 This embodiment provides a kilogram-scale batch preparation process for polyol-polyester block copolymer (PEG-b-PLA), as detailed below.

[0099] (1) Raw material pretreatment.

[0100] Polyethylene glycol (PEG2000) was vacuum dried at 80°C for 4 hours. L-lactide (L-LA) was then recrystallized and purified. The amount of PEG2000 used was 2.0 kg (1.0 mol), and the amount of L-LA used was 1.44 kg (10 mol), with a PEG to LA molar ratio of 1:10.

[0101] (2) Polymerization reaction.

[0102] Pretreated PEG2000 and L-lactide were added to a 50 L reactor, along with 10 L of anhydrous toluene, and the mixture was purged with nitrogen for protection. TBD was then added. The mixture was heated to 110 °C and stirred for 24 hours. The amount of TBD used was 6.96 g (0.05 mol), which is 0.5% of the molar amount of L-lactide.

[0103] (3) The termination of the reaction, purification and drying process were the same as in Example 1. 3.0 kg of white powdery PEG-b-PLA block copolymer was obtained, with a yield of 88%.

[0104] GPC test: Mn = 7800 g / mol =1.19, with a very narrow molecular weight distribution, and good controllability of the polymerization process.

[0105] Solid electrolyte membranes were prepared using the PEG-b-PLA block copolymer prepared in this example, following the same method as in Example 1.

[0106] The solid electrolyte membrane prepared in Example 3 was assembled into a CR2032 coin-type all-solid-state battery using the same method as in Example 1, along with an NCM622 positive electrode and a lithium metal negative electrode. Constant current charge-discharge tests were conducted at 30°C and a 0.1C rate, with a voltage range of 2.8V to 4.3V. The test results showed that the initial discharge capacity was 148.5 mAh / g, and the capacity retention rate after 200 cycles was 76.3%.

[0107] Example 4 This embodiment provides a kilogram-scale batch preparation process for polyol-polyester block copolymer (PPG-b-PLA), as detailed below.

[0108] (1) Raw material pretreatment.

[0109] Polypropylene glycol (PPG2000) was dried under vacuum at 80 °C for 4 hours. DL-lactide (DL-LA) was then recrystallized and purified. The amount of PPG2000 used was 2.0 kg (1.0 mol), and the amount of DL-LA used was 1.44 kg (10 mol), with a PPG to LA molar ratio of 1:10.

[0110] (2) Polymerization reaction.

[0111] Pretreated PPG2000 and DL-lactide were added to a 50L reactor, along with 10L of anhydrous toluene, and the mixture was purged with nitrogen. TBD was then added. The mixture was heated to 110℃ and stirred for 24 hours.

[0112] (3) The reaction termination, purification and drying process were the same as in Example 1, and 2.9 kg of white powdered PPG-b-PLA block copolymer was obtained, with a yield of 85%. The amount of TBD used was 6.96 g, 0.05 mol, which is 0.5% of the molar amount of DL-lactide.

[0113] GPC test: Mn = 7600 g / mol =1.21, with a very narrow molecular weight distribution, and good controllability of the polymerization process.

[0114] Example 5 This embodiment provides a 100 kg-scale batch preparation process for polyol-polyester block copolymer (mPEG-b-PLA). The difference from Example 1 is that the catalyst used in step (2) of the polymerization reaction is different, Sn(Oct)2 is used, and the temperature of the polymerization reaction is 130°C and the reaction time is 48 hours. The other preparation processes are the same as in Example 1, and white to slightly yellow mPEG-b-PLA is obtained with a yield of 85%.

[0115] GPC test: Mn = 7600 g / mol; =1.28, with a narrow molecular weight distribution and good controllability of the polymerization process.

[0116] Example 6 This embodiment provides a 100 kg-scale batch preparation process for polyol-polyester block copolymer (mPEG-b-PLA). The difference from Example 1 is that the catalyst used in step (2) of the polymerization reaction is different. DMAP is used, and the amount of DMAP is 1.0% of the molar amount of L-lactide. The polymerization reaction temperature is 120°C and the reaction time is 48 hours. The other preparation processes are the same as in Example 1, and white mPEG-b-PLA is obtained with a yield of 62%.

[0117] GPC test: Mn = 7600 g / mol; =1.42, indicating that DMAP was used as a catalyst with a moderate molecular weight distribution.

[0118] Example 7 This embodiment provides a 100 kg-scale batch preparation process for polyol-polyester block copolymer (mPEG-b-PLA). The difference from Example 1 is that the catalyst used in step (2) of the polymerization reaction is different. Triethylamine is used, and the amount of triethylamine is 1.0% of the molar amount of L-lactide. The temperature of the polymerization reaction is 110°C and the reaction time is 72 hours. The other preparation processes are the same as in Example 1, and white mPEG-b-PLA is obtained with a yield of 45%.

[0119] GPC test: Mn = 7600 g / mol; =1.55, indicating that triethylamine was used as a catalyst with a moderate molecular weight distribution.

[0120] Examples 1, 5, 6 and 7 were compared using different catalysts, and the results are summarized in Table 1 below.

[0121] Table 1 The test results in Table 1 show that the TBD catalyst has the best overall performance.

[0122] To better illustrate the effects of the embodiments of the present invention, the following comparative examples are compared with the embodiments described above.

[0123] Comparative Example 1 This comparative example differs from Example 1 in that it does not use a catalyst. After 24 hours of reaction, lactide hardly polymerized, and the resulting mPEG-ASSPE-Li polymer had a yield of <5% and a molecular weight of <2500 g / mol. This indicates that a catalyst is essential for the ring-opening polymerization reaction.

[0124] Solid electrolyte membranes (referred to as mPEG-ASSPE-Li) were prepared using the mPEG-ASSPE-Li polymer prepared in this comparative example.

[0125] The above-mentioned mPEG-ASSPE-Li solid electrolyte membrane was used to assemble a CR2032 coin cell all-solid-state battery using the same method as in Example 1. Constant current charge-discharge tests were conducted at 30°C and a 0.1C rate. The battery assembled in this comparative example exhibited overcharging during the first charge cycle and could not be charged and discharged normally. After several cycles, a significant short circuit appeared.

[0126] Comparative Example 2 This comparative example differs from Example 1 in that it uses unpurified lactide. Following the method in Example 1, unrecrystallized lactide with a water content of 0.05% was used. After 24 hours of reaction, the yield was only 52%. =1.48, the molecular weight distribution is broader than in Example 1, and the product is pale yellow. This indicates that the purity of the cyclic ester monomer is crucial to the polymerization reaction.

[0127] Comparative Example 3 (Reaction temperature too high) This comparative example differs from Example 1 in that the polymerization reaction temperature was raised too high. Following the method in Example 1, the reaction temperature was increased to 130°C, and after 24 hours of reaction, the yield was 72%. =1.45, the molecular weight distribution is broader than in Example 1, the product is light yellow, and there are obvious racemic byproducts. This indicates that excessively high reaction temperature will lead to an increase in side reactions.

[0128] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for the mass production of polyol-polyester block copolymers, characterized in that, The batch preparation method includes: Step S1, raw material pretreatment, includes: subjecting the polyol to a first vacuum drying to remove residual water and obtain a pretreated polyol; and recrystallizing and purifying the cyclic ester monomer in a first organic solvent, followed by a second vacuum drying to obtain the pretreated cyclic ester monomer. Step S2, polymerization reaction, includes: adding the pretreated polyol, the pretreated cyclic ester monomer and polymerization solvent into a reaction vessel, then adding a catalyst, and heating and stirring under inert gas protection to cause the pretreated polyol and the pretreated cyclic ester monomer to undergo a polymerization reaction; wherein the heating and stirring temperature is 80℃~150℃, and the heating and stirring time is 12 hours~48 hours; Step S3, terminating the reaction, includes: adding a terminator to the reaction vessel, continuing stirring, terminating the polymerization reaction, and obtaining a reaction solution; Step S4, purification, includes: placing the reaction solution in a rotary evaporator for rotary evaporation to remove the polymerization solvent, then placing it in a dissolution-precipitation apparatus for dissolution with a second organic solvent, then adding a precipitant for precipitation, filtering, and repeating the dissolution-precipitation process at least twice. Step S5, drying, includes: subjecting the product obtained in step S4 to a third vacuum drying to obtain a polyol-polyester block copolymer. The yield of a single batch of polyol-polyester block copolymer prepared by the mass production method is 1 kg to 1000 kg; the polyol-polyester block copolymer is used in solid-state batteries.

2. The mass production method according to claim 1, characterized in that, The polyols include one or more of the following: mPEG, polyethylene glycol (PEG), mPPG, polypropylene glycol (PPG), polytetrahydrofuran ether (PTMEG), polyglycerol (PG), polyvinyl alcohol (PVA), polycaprolactone diol (PCL-diol), and polylactic acid diol (PLA-diol); the number average molecular weight of the polyols is 200 g / mol to 20000 g / mol. The cyclic ester monomers include one or more of lactide (LA), glycolide (GA), caprolactone (ε-CL), valproic acid lactone (δ-VL), butyrolactone (γ-BL), trimethylene carbonate (TMC), ethylene carbonate (EC), and propylene carbonate (PC); wherein the lactide includes one or more of L-lactide, D-lactide, and DL-lactide. The molar ratio of the pretreated polyol to the pretreated cyclic ester monomer is 1:5 to 1:

100.

3. The mass production method according to claim 1, characterized in that, The catalyst comprises one or more of the following: 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), stannous octanoate (Sn(Oct)2), triethylamine, 4-dimethylaminopyridine (DMAP), stannous dichloride (SnCl2), zinc oxide (ZnO), scandium trifluoromethanesulfonate (Sc(OTf)3), and ytterbium trifluoromethanesulfonate (Yb(OTf)3); the amount of the catalyst used is 0.1% to 2.0% of the molar amount of the cyclic ester monomer.

4. The mass production method according to claim 1, characterized in that, The polymerization solvent includes one or more of acetonitrile, toluene, xylene, trimethylbenzene, chlorobenzene, tetrahydrofuran, dioxane, diethylene glycol dimethyl ether, N,N-dimethylformamide, N,N-dimethylacetamide, and dimethyl sulfoxide; The polymerization solvent is 0.5 to 3 times the total mass of the pretreated polyol and the pretreated cyclic ester monomer.

5. The mass production method according to claim 1, characterized in that, The terminator includes one or more of benzoic acid, acetic acid, citric acid, phosphoric acid, or hydrochloric acid; the amount of the terminator is 1 to 5 times the molar amount of the catalyst.

6. The mass production method according to claim 1, characterized in that, The first organic solvent includes one or more of the following: dichloromethane, chloroform, ethyl acetate, tetrahydrofuran, acetone, and N,N-dimethylformamide; The second organic solvent includes one or more of the following: dichloromethane, chloroform, ethyl acetate, tetrahydrofuran, acetone, and N,N-dimethylformamide; The precipitant includes one or more of methanol, ethanol, isopropanol, diethyl ether, petroleum ether, and n-hexane.

7. The mass production method according to claim 1, characterized in that, The heating and stirring temperature is 100℃~120℃, and the heating and stirring time is 20 hours~28 hours.

8. The mass production method according to claim 1, characterized in that, The temperature of the first vacuum drying is 80℃~100℃, and the vacuum drying time is 4 hours~6 hours; The second vacuum drying temperature is 40℃~50℃, and the vacuum drying time is 12 hours~24 hours; The temperature of the third vacuum drying is 40℃~60℃, and the vacuum drying time is 24 hours~48 hours; The reaction equipment includes a reaction vessel; the rotary evaporation equipment includes a rotary evaporator or a thin-film evaporator; the dissolution and precipitation equipment includes one or more of a dissolution vessel, a filtration device, a vacuum filtration device, a plate and frame filter press, or a centrifugal filter.

9. A polyol-polyester block copolymer prepared by any one of the mass production methods according to claims 1-8, characterized in that, The polyol-polyester block copolymer includes one or more of the following: methoxy polyethylene glycol-b-polylactide (mPEG-b-PLA), methoxy polyethylene glycol-b-polylactide (mPEG-b-PGA), methoxy polyethylene glycol-b-polycaprolactone (mPEG-b-PCL), methoxy polyethylene glycol-b-polytrimethylene carbonate (mPEG-b-PTMC), polyethylene glycol-b-polylactide (PEG-b-PLA), polyethylene glycol-b-polycaprolactone (PEG-b-PCL), polyethylene glycol-b-polylactide (PEG-b-PGA), polypropylene glycol-b-polylactide (PPG-b-PLA), polytetrahydrofuran ether-b-polylactide (PTMEG-b-PLA), polyvinyl alcohol-g-polylactide (PVA-g-PLA), and methoxy polyethylene glycol-b-polylactide (mPPG-b-PLA).

10. A solid-state battery, characterized in that, The solid-state battery includes a positive electrode, a negative electrode, and a solid electrolyte layer disposed between the positive electrode and the negative electrode, wherein the solid electrolyte layer includes the polyol-polyester block copolymer as described in claim 9.

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