Biological gel electrolyte composed of PAN and modified PLLA and preparation method thereof
阅读说明：本技术 一种pan与改性plla组成的生物凝胶电解质及其制备方法 (Biological gel electrolyte composed of PAN and modified PLLA and preparation method thereof ) 是由 潘安强 柴思敏 于 2020-12-21 设计创作，主要内容包括：本发明公开了一种PAN与改性PLLA组成的生物凝胶电解质及其制备方法。本发明这种PAN与改性PLLA组成的生物凝胶电解质的骨架膜为PAN和改性PLLA组成的纳米纤维膜,其中PAN与改性PLLA质量比为(2.5～4.5):1。本发明的原料采用了改性PLLA与PAN,利用两种材料利用两者之间的氢键作用,降低纯PAN产生的“钝化效应”,提高电化学性能,并对PLLA进行改性,进一步稳定聚合物的力学强度,从而保证本发明的PAN与改性PLLA组成的生物凝胶电解质具有力学性能和电化学性能的稳定性。(The invention discloses a biological gel electrolyte composed of PAN and modified PLLA and a preparation method thereof. The skeleton membrane of the biological gel electrolyte composed of the PAN and the modified PLLA is a nanofiber membrane composed of the PAN and the modified PLLA, wherein the mass ratio of the PAN to the modified PLLA is (2.5-4.5): 1. The raw materials of the invention adopt modified PLLA and PAN, the two materials are utilized to utilize the hydrogen bond effect between the two materials, reduce the passivation effect generated by pure PAN, improve the electrochemical performance, modify the PLLA and further stabilize the mechanical strength of the polymer, thereby ensuring that the biological gel electrolyte composed of the PAN and the modified PLLA has the stability of the mechanical property and the electrochemical property.)
1. The framework membrane of the biological gel electrolyte composed of PAN and modified PLLA is characterized in that the framework membrane is a nanofiber membrane composed of PAN and modified PLLA, wherein the mass ratio of PAN to modified PLLA is (2.5-4.5): 1.
2. The skeletal membrane of a biogel electrolyte composed of PAN and modified PLLA as claimed in claim 1, wherein the modified PLLA is a PLLA modified with ethylene glycol or co-modified with ethylene glycol and methacrylic acid, abbreviated as P (LLA-EG) and P (LLA-EG-MA), respectively; wherein n in P (LLA-EG)EG:nPLLA1 is (2-3.5); n in P (LLA-EG-MA)EG:nMA:nPLLA＝(2～3.5):(2～3.5):1。
3. The skeletal membrane of a biogel electrolyte composed of PAN and modified PLLA as claimed in claim 2, wherein the process for the preparation of P (LLA-EG) comprises the steps of:
1-1, dissolving PLLA in a mixed solution of dichloromethane and N, N-dimethylformamide, stirring until the PLLA is completely dissolved to obtain a PLLA solution, then adding ethylene glycol according to a set proportion, and uniformly stirring to obtain a PLLA-EG suspension solution;
1-2, adding stannous chloride into the PLLA-EG suspension solution in the step 1-1, then carrying out reflux reaction at a set temperature, and obtaining a P (LLA-EG) light yellow transparent solution after the reaction is finished;
1-3, adding absolute ethyl alcohol into the light yellow transparent solution of the P (LLA-EG) in the step 1-2, separating out a precipitate, and filtering, washing and drying the precipitate to obtain the P (LLA-EG).
4. The skeletal membrane of a biogel electrolyte consisting of PAN and modified PLLA according to claim 3, wherein in the step 1-1, the volume ratio of dichloromethane to N, N-dimethylformamide is (0.5-4.5) to 1, and the concentration of PLLA in the mixed solvent is 0.016-0.018 g/ml; in the step 1-2, the ratio of the mass of stannous chloride to the total mass of PLLA + EG is (0.05-0.10): 1, the set temperature is 100-180 ℃, the stirring speed is 200-300 r/min, and the reflux reaction time is 4-12 h; in the step 1-3, the drying is vacuum drying, the drying temperature is 50-70 ℃, and the drying time is 10-14 h.
5. The skeletal membrane of a biogel electrolyte consisting of PAN and modified PLLA as claimed in claim 2, wherein the process for the preparation of P (LLA-EG-MA) comprises the steps of:
2-1, dissolving PLLA in a mixed solution of dichloromethane and N, N-dimethylformamide, stirring until the PLLA is completely dissolved to obtain a PLLA solution, then adding ethylene glycol according to a set proportion, and uniformly stirring to obtain a PLLA-EG suspension solution;
2-2, adding stannous chloride into the PLLA-EG suspension solution in the step 2-1, then carrying out reflux reaction at a set temperature, and obtaining a P (LLA-EG) light yellow transparent solution after the reaction is finished;
2-3, adding methacrylic acid into the P (LLA-EG) light yellow transparent solution in the step 2-2 by using a separating funnel, then carrying out reflux reaction at a set temperature, and obtaining the P (LLA-EG-MA) light yellow transparent solution after the reaction is finished;
2-4, adding absolute ethyl alcohol into the light yellow transparent solution of the P (LLA-EG-MA) in the step 1-2, separating out a precipitate, and filtering, washing and drying the precipitate to obtain the P (LLA-EG-MA).
6. The skeletal membrane of a biogel electrolyte consisting of PAN and modified PLLA according to claim 5, wherein in the step 2-1, the volume ratio of dichloromethane to N, N-dimethylformamide is (0.5-4.5): 1, and the concentration of PLLA in the mixed solvent is 0.016-0.018 g/ml; in the step 2-2, the ratio of the mass of the stannous chloride to the total mass of the PLLA + EG + MA is (0.05-0.10): 1, the set temperature is 100-180 ℃, the stirring speed is 200-300 r/min, and the reflux reaction time is 4-12 h; in the step 2-3, the drying is vacuum drying, the drying temperature is 50-70 ℃, and the drying time is 10-14 h.
7. The method for preparing the bio-gel electrolyte from the bio-gel electrolyte framework membrane consisting of PAN and modified PLLA according to any one of claims 1-6, comprising the following steps:
3-1, adding the modified PLLA into a solvent, uniformly stirring to obtain a modified PLLA suspension, adding PAN according to a set proportion, and stirring to completely dissolve at a set temperature to obtain PAN/modified PLLA spinning solution;
3-2, performing electrostatic spinning on the PAN/modified PLLA spinning solution obtained in the step 3-1, and drying after spinning is finished to obtain a skeleton membrane of the biogel electrolyte consisting of PAN and modified PLLA;
3-3, cutting the skeleton membrane of the bio-gel electrolyte composed of the PAN and the modified PLLA in the step 3-2 into a circular sheet with the diameter d being 19mm, adding a LiTFSI solution sucked by a dropper into a glove box filled with argon into a container for placing the PAN/P (LLA-EG-MA) skeleton membrane, soaking, swelling and plasticizing, completely sucking the redundant electrolyte on the surface of the PAN/P (LLA-EG-MA) polymer electrolyte by using filter paper to obtain the bio-gel electrolyte composed of the PAN and the modified PLLA, and assembling the bio-gel electrolyte into a battery.
8. The method for preparing the biogel electrolyte from the biogel electrolyte skeleton membrane consisting of the PAN and the modified PLLA as claimed in claim 7, wherein in the step 3-1, the solvent is DMF, the total concentration of the modified PLLA and the PAN in the solvent is 0.07-0.09 g/mL, the set temperature is 40-80 ℃, the stirring speed is 600-800 r/min, and the stirring time is 10-14 h.
9. The method for preparing the bio-gel electrolyte from the bio-gel electrolyte skeleton membrane consisting of PAN and modified PLLA according to claim 7, wherein in the step 3-2, a 10mL injector is adopted for electrostatic spinning, the low voltage strength is-0.1 kV, the high voltage strength is 14-16 kV, the injection speed is 0.06-0.08 mm/min, and the electrospinning time is 10-13 h; the thickness of the electrostatic spinning membrane is 50-80 μm.
10. The method for preparing the biogel electrolyte from the biogel electrolyte skeleton membrane consisting of the PAN and the modified PLLA as claimed in claim 7, wherein in the step 3-3, the concentration of the LiTFSI solution is 1M, 0.2-0.8 mL of the LiTFSI solution is dripped into each PAN/P (LLA-EG-MA) skeleton membrane, and the soaking, swelling and plasticizing time is 10-14 h.
Technical Field
The invention belongs to the field of material chemistry, and particularly relates to a biological gel electrolyte composed of PAN and modified PLLA and a preparation method thereof.
Background
Compared with inorganic solid electrolytes, gel polymer electrolytes not only have good mechanical properties of solid electrolytes, but also have high ionic conductivity of liquid electrolytes. Lithium ions can therefore be transported in gel polymer electrolytes by means of both the movement of the polymer chains and the swollen gel or liquid phase. Gel polymers are considered to be the best candidates for replacement of commercial liquid electrolytes.
Polyacrylonitrile (PAN) is widely used for the construction of polymer electrolyte matrix materials due to its high ionic conductivity and electrochemical oxidation resistance, while the ionic conductivity of the gel polymer electrolyte constructed therefrom is about 10 at 298K-3S cm-1. However, CN groups in pure PAN are liable to react with the Li anode, and a "passivation layer" is formed between the Li metal cathode and the PAN electrolyte, resulting in increased interface impedance, hindered ion transport, and deteriorated electrochemical performance. Mixing with other polymers or inorganic materials can alleviate this problem to some extent.
As a biodegradable high polymer material, the L-polylactic acid (PLLA) has good mechanical properties, flexible molecular chains and long degradable time, and becomes one of candidate materials of medical artificial frameworks. Meanwhile, PLLA is a high-polarity cellulose derivative, and has strong liquid electrolyte absorbability, and researches show that when polylactic acid is independently used as a matrix material of a polymer electrolyte framework, the electrochemical performance of the battery is poor due to the crystallization behavior of the polylactic acid. The hydroxyl of the electron-withdrawing group in the PLLA can form intermolecular hydrogen bonds with CN groups in the PAN, so that the passivation effect generated by pure PAN is reduced. However, the hydrogen bonding force is weak, so that the prepared polymer film has low mechanical strength, and therefore, covalent bonds are formed through monomer copolymerization crosslinking, and a chemical crosslinking network is formed in the polymer film to improve the mechanical strength and the structural stability of the polymer film.
The existing methods for preparing the polymer electrolyte membrane skeleton mainly comprise a solution pouring method, an extraction activation method, a phase separation/inversion method and the like, wherein the solution pouring method is to dissolve a polymer in a conventional solvent and then pour the polymer in a specific mould for forming, but due to the solvation effect of lithium salt, the solvent is difficult to be completely removed. The extraction activation method is that a plasticizer is added into a polymer solution system, after casting and film forming, the plasticizer is removed by solvent extraction to obtain a polymer porous film, and the polymer porous film obtained by the method has uneven pore distribution; the phase separation/inversion method avoids the extraction process of the plasticizer, and the obtained polymer gel electrolyte has good electrochemical and mechanical properties, but the residual solvent can influence the electrochemical stability and safety of the battery.
Disclosure of Invention
The invention aims to provide a biogel electrolyte composed of PAN and modified PLLA and having good electrochemical stability and good mechanical property and a preparation method thereof.
The skeleton membrane of the biological gel electrolyte composed of the PAN and the modified PLLA is a nanofiber membrane composed of the PAN and the modified PLLA, wherein the mass ratio of the PAN to the modified PLLA is (2.5-4.5): 1.
The modified PLLA is the PLLA modified by ethylene glycol or jointly modified by ethylene glycol and methacrylic acid, and is respectively abbreviated as P (LLA-EG) and P (LLA-EG-MA); wherein n in P (LLA-EG)EG:nPLLA1 is (2-3.5); n in P (LLA-EG-MA)EG:nMA:nPLLA＝(2～3.5):(2～3.5):1。
The preparation method of the P (LLA-EG) comprises the following steps:
1-1, dissolving PLLA in a mixed solution of dichloromethane and N, N-dimethylformamide, stirring until the PLLA is completely dissolved to obtain a PLLA solution, then adding ethylene glycol according to a set proportion, and uniformly stirring to obtain a PLLA-EG suspension solution;
1-2, adding stannous chloride into the PLLA-EG suspension solution in the step 1-1, then carrying out reflux reaction at a set temperature, and obtaining a P (LLA-EG) light yellow transparent solution after the reaction is finished;
1-3, adding absolute ethyl alcohol into the light yellow transparent solution of the P (LLA-EG) in the step 1-2, separating out a precipitate, filtering, washing, drying and grinding the precipitate to obtain P (LLA-EG) powder.
In the step 1-1, the volume ratio of dichloromethane to N, N-dimethylformamide is (0.5-4.5): 1, and the concentration of PLLA in the mixed solvent is 0.016-0.018 g/ml; the molar ratio of PLLA to EG added is nEG:nPLLA1, in the step 1-2, the ratio of the mass of stannous chloride to the total mass of PLLA + EG is (0.05-0.10): 1, the set temperature is 100-200 ℃, the stirring speed is 200-300 r/min, and the reflux reaction time is 4-12 h; in the step 1-3, the drying is vacuum drying, the drying temperature is 50-70 ℃, and the drying time is 10-14 h.
The preparation method of the P (LLA-EG-MA) comprises the following steps:
2-1, dissolving PLLA in a mixed solution of dichloromethane and N, N-dimethylformamide, stirring until the PLLA is completely dissolved to obtain a PLLA solution, then adding ethylene glycol according to a set proportion, and uniformly stirring to obtain a PLLA-EG suspension solution;
2-2, adding stannous chloride into the PLLA-EG suspension solution in the step 2-1, then carrying out reflux reaction at a set temperature, and obtaining a P (LLA-EG) light yellow transparent solution after the reaction is finished;
2-3, adding methacrylic acid into the P (LLA-EG) light yellow transparent solution in the step 2-2 by using a separating funnel, then carrying out reflux reaction at a set temperature, and obtaining the P (LLA-EG-MA) light yellow transparent solution after the reaction is finished;
2-4, adding absolute ethyl alcohol into the light yellow transparent solution of the P (LLA-EG-MA) in the step 2-3, separating out a precipitate, filtering, washing, drying and grinding the precipitate to obtain P (LLA-EG-MA) powder.
In the step 2-1, the volume ratio of dichloromethane to N, N-dimethylformamide is (0.5-4.5): 1, the molar ratio of PLLA to EG is 1, (2-3.5), and the concentration of P (LLA-EG) in the mixed solvent is 0.016-0.018 g/ml; in the step 2-2, the ratio of the mass of the stannous chloride to the total mass of the PLLA + EG + MA is (0.05-0.10): 1, the set temperature is 100-180 ℃, the stirring speed is 200-300 r/min, and the reflux reaction time is 4-12 h; in the step 2-3, the molar ratio (2-3.5) of the addition amount of the methacrylic acid MA to the PLLA is 1; in the step 2-4, the drying is vacuum drying, the drying temperature is 50-70 ℃, and the drying time is 10-14 h.
The preparation method of the bio-gel electrolyte composed of PAN and modified PLLA comprises the following steps:
3-1, adding the modified PLLA into a solvent, uniformly stirring to obtain a modified PLLA suspension, adding PAN according to a set proportion, and stirring to completely dissolve at a set temperature to obtain PAN/modified PLLA spinning solution;
3-2, performing electrostatic spinning on the PAN/modified PLLA spinning solution obtained in the step 3-1, and drying after spinning is finished to obtain a skeleton membrane of the biogel electrolyte consisting of PAN and modified PLLA;
3-3, cutting the skeleton membrane of the bio-gel electrolyte composed of the PAN and the modified PLLA in the step 3-2 into a circular sheet with the diameter d being 19mm, adding a LiTFSI solution sucked by a dropper into a glove box filled with argon into a container for placing the PAN/P (LLA-EG-MA) skeleton membrane, soaking, swelling and plasticizing, completely sucking the redundant electrolyte on the surface of the PAN/P (LLA-EG-MA) polymer electrolyte by using filter paper to obtain the bio-gel electrolyte composed of the PAN and the modified PLLA, and assembling the bio-gel electrolyte into a battery.
In the step 3-1, the solvent is DMF, the total concentration of the modified PLLA and the PAN in the solvent is 0.07-0.09 g/mL, the set temperature is 40-80 ℃, the stirring speed is 600-800 r/min, and the stirring time is 10-14 h.
In the step 3-2, a 10mL injector is adopted for electrostatic spinning, the low voltage intensity is-0.1 kV, the high voltage intensity is 14-16 kV, the injection speed is 0.06-0.08 mm/min, and the electrospinning time is 10-13 h; the thickness of the electrostatic spinning membrane is 50-80 μm.
In the step 3-3, the concentration of the LiTFSI solution is 1M, 0.2-0.8 mL of each PAN/P (LLA-EG-MA) skeleton film is dripped, and the infiltration swelling plasticizing time is 10-14 h.
The molecular weight of the PAN is 140000-160000 g/mol; the molecular weight of PLLA is 40000-60000 g/mol.
The principle of the invention is as follows: the hydroxyl of the electron-withdrawing group in the PLLA can form intermolecular hydrogen bonds with CN groups in the PAN, so that the passivation effect generated by pure PAN is reduced. But the acting force of the hydrogen bond is weaker, so that the mechanical strength of the prepared polymer film is lower; the invention modifies PLLA, modifies by introducing ethylene glycol and methacrylic acid, forms covalent bonds by monomer copolymerization crosslinking, and forms a chemical crosslinking network in a polymer film to improve the mechanical strength and the structural stability of the polymer film.
The invention has the beneficial effects that: 1) the invention adopts the electrostatic spinning method to prepare PAN/P (LLA-EG) and PAN/P (LLA-EG-MA) cross-linked polymer membranes, the porous polymer membranes are formed by overlapping nano fibers, the formed pores can provide good ion channels, and the nano fibers are also easily activated and gelatinized by liquid electrolyte, and meanwhile, the method can effectively regulate and control the fine structure of the fibers. The prepared PAN/P (LLA-EG-MA) crosslinked polymer membrane has chemical bonds and hydrogen bonds among molecules, has stronger structural stability, has uniform distribution of the thickness of a framework membrane and the diameter size of a fiber of the blended polymer electrolyte, has better non-crystallinity, is economic and environment-friendly, and has better stability, stronger practicability and better industrial prospect. 2) The raw materials of the invention adopt modified PLLA and PAN, the two materials are utilized to utilize the hydrogen bond effect between the two materials, reduce the passivation effect generated by pure PAN, improve the electrochemical performance, modify the PLLA and further stabilize the mechanical strength of the polymer, thereby ensuring that the biological gel electrolyte composed of the PAN and the modified PLLA has the stability of the mechanical property and the electrochemical property.
Drawings
FIG. 1 is an XRD pattern of P (LLA-EG) precursor prepared in example 1 of the present invention.
FIG. 2 is an XRD pattern of a PAN/P (LLA-EG) crosslinked polymer film prepared according to example 1 of the present invention.
FIG. 3 is an SEM image of a PAN/P (LLA-EG) crosslinked polymer membrane prepared in example 1 of the present invention.
FIG. 4 is an SEM image of a cross-linked polymer PAN/P (LLA-EG-MA) membrane prepared in example 6 of the present invention.
FIG. 5 is a LSV plot of a cross-linked polymer PAN/P (LLA-EG-MA) film prepared in example 6 of the present invention.
FIG. 6 is a graph of the interfacial resistance of a cross-linked polymer PAN/P (LLA-EG-MA) film prepared in example 6 of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments, and all other embodiments obtained by those skilled in the art without any creative work based on the embodiments of the present invention belong to the protection scope of the present invention.
In this example, unless otherwise specified, the chemical reagents used were analytical reagents, all of which were common commercial products or prepared by conventional means, and the equipment used was conventional in the art, and the following are some examples of the inventors in the experiment:
the molecular weight of the PAN is 150000 g/mol; the molecular weight of PLLA was 50000 g/mol.
Example 1
The invention provides a preparation method of PAN/P (LLA-EG) bio-based gel polymer electrolyte, which comprises the following steps:
(1) according to VCH3Cl2：VDMF0.5:1 volume ratio (total volume 60mL) the corresponding volume of dichloromethane (CH) was measured3Cl2) Adding N, N-Dimethylformamide (DMF) solvent into a beaker, stirring to obtain a mixed solvent, weighing 1g of PLLA powder, adding the PLLA powder into the mixed solvent, and stirring at normal temperature until the PLLA powder is completely dissolved to obtain a PLLA solution;
(2) according to nEG:nPLLAWeighing ethylene glycol solution with the corresponding volume according to the molar ratio of 2:1, and adding the ethylene glycol solution into the PLLA solution obtained in the step (1) under the condition of stirring to obtain a P (LLA-EG) mixed suspension;
(3) according to mSnCl2:mPLLA+EGWeighing stannous chloride with corresponding mass according to the ratio of 0.05:1, and adding the stannous chloride into the P (LLA-EG) mixed suspension obtained in the step (2);
(4) transferring the P (LLA-EG) mixed suspension obtained in the step (3) into a conical flask, putting the conical flask into an oil bath kettle, carrying out reflux reaction for 4h under the conditions of 100 ℃ and 250r/min, and cooling to room temperature to obtain a P (LLA-EG) light yellow transparent solution;
(5) adding absolute ethyl alcohol into the P (LLA-EG) light yellow transparent solution obtained in the step (4) intermittently until no white suspended matter is generated, continuing to perform suction filtration and washing for a plurality of times by using the absolute ethyl alcohol, and drying the suction filtration product in a vacuum drying oven at 60 ℃ for 12 hours to obtain a P (LLA-EG) micro-nano multi-level structure precursor;
(6) weighing a certain amount of PAN powder, adding into 10ml of DMF solvent, stirring at 50 ℃ and 700r/min until the PAN powder is completely dissolved to obtain a light yellow transparent solution, and mixing according to mPAN:mP(LLA-EG)Weighing the P (LLA-EG) precursor powder obtained in the step (5) according to the mass ratio of 3:1, adding the precursor powder into the PAN solution, stirring the mixture at the temperature of 50 ℃ and the speed of 700r/min till the precursor powder is completely dissolved, and continuously stirring the mixture for 12 hours to obtain the CPAN/P(LLA-EG)0.08g/mL yellow clear solution;
(7) and (4) adding the PAN/P (LLA-EG) solution obtained in the step (6) into a 10ml syringe, and performing electrostatic spinning under the conditions that the low voltage strength is-0.1 kV, the high voltage strength is 15kV, and the injection speed is 0.065 mm/min.
(8) And (3) drying the PAN/P (LLA-EG) polymer film obtained in the step (3) in vacuum at 60 ℃ for 12h, cutting the dried film into circular sheets with the diameter d being 19mm (the thickness of the film sheet is 50 mu M), sucking 0.3ml of 1M LiTFSI (DOL: DME,1:1, v: v) by a dropper in an argon-filled glove box, adding the circular sheets into a container in which the PAN/P (LLA-EG) polymer film is placed, soaking for 12h for swelling and plasticizing, sucking the redundant electrolyte on the surface of the PAN/P (LLA-EG) polymer electrolyte by using filter paper, and assembling the battery.
FIG. 1 is the XRD pattern of the P (LLA-EG) precursor product prepared in example 1, from which it can be seen that the product is a phase-pure P (LLA-EG) triblock cross-linked product with good crystallinity; FIG. 2 is an XRD pattern of the PAN/P (LLA-EG) polymer film prepared in example 1, from which it can be seen that the crystallinity of the obtained PAN/P (LLA-EG) polymer film is significantly reduced, which is beneficial to the movement of polymer chains and the transmission of lithium ions; FIG. 3 shows the Li// PAN/P (LLA-EG)// Li symmetrical cell assembled by PAN/P (LLA-EG) polymer film prepared in example 1 at 0.15mA cm-1，0.15mA h cm-1Cycle performance under the conditions shown in the figure, the obtained PAN/P (LLA-EG) batteryThe cycle under the test condition of 450h still can keep better cycle stability.
Example 2
The invention provides a structural design and preparation method of PAN/P (LLA-EG) bio-based gel polymer electrolyte, which comprises the following steps:
(1) according to VCH3Cl2:VDMFMethylene Chloride (CH) was measured in a volume ratio of 1:1 (60 mL in total) in a corresponding volume3Cl2) Adding N, N-Dimethylformamide (DMF) solvent into a beaker, stirring to obtain a mixed solvent, weighing 1g of PLLA powder, adding the PLLA powder into the mixed solvent, and stirring at normal temperature until the PLLA powder is completely dissolved to obtain a PLLA solution;
(2) according to nEG:nPLLAAdding ethylene glycol solution with the corresponding volume in a molar ratio of 2.5:1 into the PLLA solution obtained in the step (1) under stirring to obtain a P (LLA-EG) mixed suspension;
(3) according to mSnCl2:mPLLA+EGWeighing stannous chloride with corresponding mass according to the ratio of 0.05:1, and adding the stannous chloride into the P (LLA-EG) mixed suspension obtained in the step (2);
(4) transferring the P (LLA-EG) mixed suspension obtained in the step (3) into a conical flask, putting the conical flask into an oil bath kettle, carrying out reflux reaction for 6h at the temperature of 120 ℃ and at the speed of 250r/min, and cooling to room temperature to obtain a P (LLA-EG) light yellow transparent solution;
(5) adding absolute ethyl alcohol into the P (LLA-EG) light yellow transparent solution obtained in the step (4) intermittently until no white suspended matter is generated, continuing to perform suction filtration and washing for a plurality of times by using the absolute ethyl alcohol, and drying the suction filtration product in a vacuum drying oven at 60 ℃ for 12 hours to obtain a P (LLA-EG) micro-nano multi-level structure precursor;
(6) weighing a certain amount of PAN powder, adding into 10ml of DMF solvent, stirring at 50 ℃ and 700r/min until the PAN powder is completely dissolved to obtain a light yellow transparent solution, and mixing according to mPAN:mP(LLA-EG)Weighing the P (LLA-EG) precursor powder obtained in the step (5) according to the mass ratio of 3:1, adding the precursor powder into the PAN solution, stirring the mixture at the temperature of 50 ℃ and the speed of 700r/min till the precursor powder is completely dissolved, and continuously stirring the mixture for 12 hours to obtain the CPAN/P(LLA-EG)0.08g/mL yellow clear solution;
(7) adding the PAN/P (LLA-EG) solution obtained in the step (6) into a 10ml injector, and performing electrostatic spinning under the conditions that the low voltage strength is-0.1 kV, the high voltage strength is 15kV and the injection speed is 0.07 mm/min; the electrospinning time is 11 h;
(8) and (3) drying the PAN/P (LLA-EG) polymer film obtained in the step (3) in vacuum at 60 ℃ for 12h, cutting the dried film into circular slices (the thickness of the film is 60 mu M) with the diameter d being 19mm, sucking 0.5ml of 1M LiTFSI (DOL: DME,1:1, v: v) by a dropper in an argon-filled glove box, adding the circular slices into a container for placing the PAN/P (LLA-EG) polymer film, soaking for 12h for swelling and plasticizing, sucking the redundant electrolyte on the surface of the PAN/P (LLA-EG) polymer electrolyte by using filter paper, and assembling the battery.
Example 3
The invention provides a structural design and preparation method of PAN/P (LLA-EG) bio-based gel polymer electrolyte, which comprises the following steps:
(1) according to VCH3Cl2:VDMFMethylene Chloride (CH) was measured in a volume ratio of 3:1 (60 mL in total) in a corresponding volume3Cl2) Adding N, N-Dimethylformamide (DMF) solvent into a beaker, stirring to obtain a mixed solvent, weighing 1g of PLLA powder, adding the PLLA powder into the mixed solvent, and stirring at normal temperature until the PLLA powder is completely dissolved to obtain a PLLA solution;
(2) according to nEG:nPLLAWeighing ethylene glycol solution with the corresponding volume according to the molar ratio of 3:1, and adding the ethylene glycol solution into the PLLA solution obtained in the step (1) under the condition of stirring to obtain a P (LLA-EG) mixed suspension;
(3) according to mSnCl2:mPLLA+EGWeighing stannous chloride with corresponding mass according to the ratio of 0.08:1, and adding the stannous chloride into the P (LLA-EG) mixed suspension obtained in the step (2);
(4) transferring the P (LLA-EG) mixed suspension obtained in the step (3) into a conical flask, putting the conical flask into an oil bath kettle, carrying out reflux reaction for 8 hours at 140 ℃ under the condition of 250r/min, and cooling to room temperature to obtain a P (LLA-EG) light yellow transparent solution;
(5) adding absolute ethyl alcohol into the P (LLA-EG) light yellow transparent solution obtained in the step (4) intermittently until no white suspended matter is generated, continuing to perform suction filtration and washing for a plurality of times by using the absolute ethyl alcohol, and drying the suction filtration product in a vacuum drying oven at 60 ℃ for 12 hours to obtain a P (LLA-EG) micro-nano multi-level structure precursor;
(6) weighing a certain amount of PAN powder, adding into 10ml of DMF solvent, stirring at 50 ℃ and 700r/min until the PAN powder is completely dissolved to obtain a light yellow transparent solution, and mixing according to mPAN:mP(LLA-EG)Weighing the P (LLA-EG) precursor powder obtained in the step (5) according to the mass ratio of 3:1, adding the precursor powder into the PAN solution, stirring the mixture at the temperature of 50 ℃ and the speed of 700r/min till the precursor powder is completely dissolved, and continuously stirring the mixture for 12 hours to obtain the CPAN/P(LLA-EG)0.08g/mL yellow clear solution;
(7) adding the PAN/P (LLA-EG) solution obtained in the step (6) into a 10ml injector, and performing electrostatic spinning under the conditions that the low voltage strength is-0.1 kV, the high voltage strength is 15kV and the injection speed is 0.07 mm/min; the electrospinning time is 11 h;
(8) and (3) drying the PAN/P (LLA-EG) polymer film obtained in the step (3) in vacuum at 60 ℃ for 12h, cutting the dried film into circular slices (the thickness of the film is 60 mu M) with the diameter d being 19mm, sucking 0.5ml of 1M LiTFSI (DOL: DME,1:1, v: v) by a dropper in an argon-filled glove box, adding the circular slices into a container for placing the PAN/P (LLA-EG) polymer film, soaking for 12h for swelling and plasticizing, sucking the redundant electrolyte on the surface of the PAN/P (LLA-EG) polymer electrolyte by using filter paper, and assembling the battery.
Example 4
The invention provides a structural design and preparation method of PAN/P (LLA-EG) bio-based gel polymer electrolyte, which comprises the following steps:
(1) according to VCH3Cl2:VDMFMethylene Chloride (CH) was measured in a volume ratio of 3.5:1 (60 mL in total)3Cl2) Adding N, N-Dimethylformamide (DMF) solvent into a beaker, stirring to obtain a mixed solvent, weighing 1g of PLLA powder, adding the PLLA powder into the mixed solvent, and stirring at normal temperature until the PLLA powder is completely dissolved to obtain a PLLA solution;
(2) according to nEG:nPLLAAdding a glycol solution in a molar ratio of 3.5:1 into the PLLA solution obtained in the step (1) under stirring to obtain a P (LLA-EG) mixed suspension;
(3) according to mSnCl2:mPLLA+EGWeighing stannous chloride at a ratio of 0.08:1, and adding the stannous chloride into the mixed suspension of the P (LLA-EG) obtained in the step (2);
(4) transferring the P (LLA-EG) mixed suspension obtained in the step (3) into a conical flask, putting the conical flask into an oil bath kettle, carrying out reflux reaction for 10 hours at the temperature of 100 ℃ and at the speed of 250r/min, and cooling to room temperature to obtain a P (LLA-EG) light yellow transparent solution;
(5) adding absolute ethyl alcohol into the P (LLA-EG) light yellow transparent solution obtained in the step (4) intermittently until no white suspended matter is generated, continuing to perform suction filtration and washing for a plurality of times by using the absolute ethyl alcohol, and drying the suction filtration product in a vacuum drying oven at 60 ℃ for 12 hours to obtain a P (LLA-EG) micro-nano multi-level structure precursor;
(6) weighing a certain amount of PAN powder, adding into 10ml of DMF solvent, stirring at 50 ℃ and 700r/min until the PAN powder is completely dissolved to obtain a light yellow transparent solution, and mixing according to mPAN:mPLLAWeighing the P (LLA-EG) precursor powder obtained in the step (5) according to the mass ratio of 3:1, adding the precursor powder into the PAN solution, stirring the mixture at the temperature of 50 ℃ and the speed of 700r/min till the precursor powder is completely dissolved, and continuously stirring the mixture for 12 hours to obtain the CPAN/P(LLA-EG)0.08g/mL yellow clear solution;
(7) adding the PAN/P (LLA-EG) solution obtained in the step (6) into a 10ml injector, and performing electrostatic spinning under the conditions that the low voltage strength is-0.1 kV, the high voltage strength is 15kV and the injection speed is 0.08mm/min, wherein the electrospinning time is 12 h;
(8) and (3) drying the PAN/P (LLA-EG) polymer film obtained in the step (3) in vacuum at 60 ℃ for 12h, cutting the dried film into circular slices (the thickness of the film is 70 mu M) with the diameter d being 19mm, sucking 0.7ml of 1M LiTFSI (DOL: DME,1:1, v: v) by a dropper in an argon-filled glove box, adding the circular slices into a container for placing the PAN/P (LLA-EG) polymer film, soaking for 12h for swelling and plasticizing, sucking the redundant electrolyte on the surface of the PAN/P (LLA-EG) polymer electrolyte by using filter paper, and assembling the battery.
Example 5
The invention provides a structural design and preparation method of PAN/P (LLA-EG) bio-based gel polymer electrolyte, which comprises the following steps:
(1) according to VCH3Cl2：VDMF4.5:1 volume ratio (60 mL in total), the corresponding volume of methylene Chloride (CH) was measured3Cl2) Adding N, N-Dimethylformamide (DMF) solvent into a beaker, stirring to obtain a mixed solvent, and weighing 1gAdding PLLA powder into the mixed solvent and stirring at normal temperature until the PLLA powder is completely dissolved to obtain a PLLA solution;
(2) according to nEG:nPLLAAdding ethylene glycol solution with corresponding volume in a molar ratio of 3.5:1 into the PLLA solution obtained in the step (1) under stirring to obtain a P (LLA-EG) mixed suspension;
(3) according to mSnCl2:mPLLA+EGWeighing stannous chloride with corresponding mass according to the ratio of 0.10:1, and adding the stannous chloride into the P (LLA-EG) mixed suspension obtained in the step (2);
(4) transferring the P (LLA-EG) mixed suspension obtained in the step (3) into a conical flask, putting the conical flask into an oil bath kettle, carrying out reflux reaction for 12 hours at 180 ℃ and 250r/min, and cooling to room temperature to obtain a P (LLA-EG) light yellow transparent solution;
(5) adding absolute ethyl alcohol into the P (LLA-EG) light yellow transparent solution obtained in the step (4) intermittently until no white suspended matter is generated, continuing to perform suction filtration and washing for a plurality of times by using the absolute ethyl alcohol, and drying the suction filtration product in a vacuum drying oven at 60 ℃ for 12 hours to obtain a P (LLA-EG) micro-nano multi-level structure precursor;
(6) weighing a certain amount of PAN powder, adding into 10ml of DMF solvent, stirring at 50 ℃ and 700r/min until the PAN powder is completely dissolved to obtain a light yellow transparent solution, and mixing according to mPAN:mPLLAWeighing the P (LLA-EG) precursor powder obtained in the step (5) according to the mass ratio of 3:1, adding the precursor powder into the PAN solution, stirring the mixture at the temperature of 50 ℃ and the speed of 700r/min till the precursor powder is completely dissolved, and continuously stirring the mixture for 12 hours to obtain the CPAN/P(LLA-EG)0.08g/mL yellow clear solution;
(7) adding the PAN/P (LLA-EG) solution obtained in the step (6) into a 10ml syringe, and performing electrostatic spinning under the conditions that the low voltage strength is-0.1 kV, the high voltage strength is 15kV and the injection speed is 0.085mm/min, wherein the electrospinning time is 13 h;
(8) and (3) drying the PAN/P (LLA-EG) polymer film obtained in the step (3) in vacuum at 60 ℃ for 12h, cutting the dried film into circular sheets (the thickness of the film sheet is 80 mu M) with the diameter d being 19mm, adding 0.3-0.8 ml of 1M LiTFSI (DOL: DME,1:1, v: v) into a container in which the PAN/P (LLA-EG) polymer film is placed in an argon-filled glove box by using a dropper, infiltrating for 12h, swelling and plasticizing, completely absorbing the redundant electrolyte on the surface of the PAN/P (LLA-EG) polymer film by using filter paper, and assembling the battery.
Example 6
The invention provides a preparation method of the PAN/P (LLA-EG-MA) biological gel polymer electrolyte, which comprises the following steps:
(1) according to VCH3Cl2:VDMFMethylene Chloride (CH) was measured in a volume ratio of 0.5:1 (60 mL in total) in a corresponding volume3Cl2) Adding N, N-Dimethylformamide (DMF) solvent into a conical flask, stirring to obtain a mixed solvent, weighing 1g of PLLA powder, adding into the mixed solvent, and stirring at normal temperature until the PLLA powder is completely dissolved to obtain a PLLA solution;
(2) according to nEG:nPLLAEthylene Glycol (EG) was metered in a volume corresponding to a molar ratio of 2:1, mSnCl2:mPLLA+EG+MA0.05:1, weighing stannous chloride, adding the stannous chloride into the mixed suspension obtained in the step (1), and carrying out condensation reflux reaction for 4 hours at the temperature of 100 ℃ and at the speed of 250r/min to obtain a P (LLA-EG) light yellow transparent solution;
(3) according to nMA:nPLLAAdding a Methacrylic Acid (MA) solution into the P (LLA-EG) light yellow transparent solution obtained in the step (2) with a separating funnel while the solution is hot, and carrying out condensation reflux reaction for 4h at the temperature of 100 ℃ and the speed of 250r/min to obtain a P (LLA-EG-MA) light yellow transparent oily solution;
(4) adding absolute ethyl alcohol into the P (LLA-EG-MA) oily solution obtained in the step (3), precipitating, washing for a plurality of times, filtering, and vacuum drying at 60 ℃ for 12 hours to obtain a P (LLA-EG-MA) cross-linked product;
(5) weighing 0.2g P (LLA-EG-MA) powder, adding into 10ml DMF solvent, stirring to obtain P (LLA-EG-MA) suspension, and mixing according to mPAN:mP(LLA-EG-MA)Weighing PAN according to the mass ratio of 2.5:1, adding the PAN into the P (LLA-EG-MA) suspension, stirring the mixture at the temperature of 50 ℃ at 700r/min until the PAN is completely dissolved, and continuing stirring the mixture for 12 hours;
(6) adding the PAN/P (LLA-EG-MA) solution obtained in the step (5) into a 10ml syringe, and performing electrostatic spinning under the conditions that the low voltage strength is-0.1 kV, the high voltage strength is 15kV and the injection speed is 0.065 mm/min; the electrospinning time is 10 h;
(7) and (3) drying the PAN/P (LLA-EG-MA) polymer film obtained in the step (6) in vacuum at 60 ℃ for 12h, cutting the dried film into circular slices (the thickness of the film is 50 mu M) with the diameter d being 19mm, sucking 0.3ml of 1M LiTFSI (DOL: DME,1:1, v: v) by a dropper in an argon-filled glove box, adding the circular slices into a container in which the PAN/P (LLA-EG-MA) polymer film is placed, infiltrating for 12h, swelling and plasticizing, and sucking off the redundant electrolyte on the surface of the PAN/P (LLA-EG-MA) polymer electrolyte by using filter paper to assemble the battery.
FIG. 4 is an SEM image of the cross-linked polymer PAN/P (LLA-EG-MA) membrane prepared in example 6, wherein the cross-linked polymer PAN/P (LLA-EG-MA) membrane is composed of overlapping nanofibers, the diameter of the nanofibers is about 100-500 nm, and the pores formed by the fibers are more favorable for the polymer membrane to absorb the electrolyte; FIG. 5 is a LSV plot of PAN/P (LLA-EG-MA) gel polymer electrolyte prepared in example 6, from which it can be seen that the electrochemical stability window of the gel polymer electrolyte is about 4.89V, which is higher than that of the current commercial lithium iron phosphate, indicating the high voltage positive electrode material of the polymer electrolyte; FIG. 6 is a graph of the interfacial resistance of PAN/P (LLA-EG-MA) gel polymer electrolyte prepared in example 6, from which it can be obtained that the interfacial resistance of the gel electrolyte is only 2.3. omega.
Example 7
The invention provides a preparation method of the PAN/P (LLA-EG-MA) biological gel polymer electrolyte, which comprises the following steps:
(1) according to VCH3Cl2:VDMFMethylene Chloride (CH) was measured in a volume ratio of 2.5:1 (60 mL in total) in a corresponding volume3Cl2) Adding N, N-Dimethylformamide (DMF) solvent into a conical flask, stirring to obtain a mixed solvent, weighing 1g of PLLA powder, adding into the mixed solvent, and stirring at normal temperature until the PLLA powder is completely dissolved to obtain a PLLA solution;
(2) according to nEG:nPLLAEthylene Glycol (EG) was metered in a volume corresponding to a molar ratio of 2.5:1, and the molar ratio was mSnCl2:mPLLA+EG+MA0.07: 1, weighing stannous chloride, adding the stannous chloride into the mixed suspension obtained in the step (1), and carrying out condensation reflux reaction for 6 hours at the temperature of 140 ℃ under the condition of 250r/min to obtain a P (LLA-EG) light yellow transparent solution;
(3) according to nMA:nPLLAAdding a Methacrylic Acid (MA) solution into the P (LLA-EG) light yellow transparent solution obtained in the step (2) at a molar ratio of 3:1 while the solution is hot by using a separating funnel, and carrying out condensation reflux reaction for 4h at 140 ℃ under the condition of 250r/min to obtain a P (LLA-EG-MA) light yellow transparent oily solution;
(4) adding absolute ethyl alcohol into the P (LLA-EG-MA) oily solution obtained in the step (3), precipitating, washing for a plurality of times, filtering, and vacuum drying at 60 ℃ for 12 hours to obtain a P (LLA-EG-MA) cross-linked product;
(5) weighing 0.2g P (LLA-EG-MA) powder, adding into 10ml DMF solvent, stirring to obtain P (LLA-EG-MA) suspension, and mixing according to mPAN:mP(LLA-EG-MA)Weighing PAN according to the mass ratio of 3:1, adding the PAN into the P (LLA-EG-MA) suspension, stirring the mixture at 70 ℃ at 700r/min until the PAN is completely dissolved, and continuing stirring the mixture for 12 hours;
(6) adding the PAN/P (LLA-EG-MA) solution obtained in the step (5) into a 10ml injector, and performing electrostatic spinning under the conditions that the low voltage strength is-0.1 kV, the high voltage strength is 15kV and the injection speed is 0.07mm/min, wherein the electrospinning time is 12 h;
(7) and (3) drying the PAN/P (LLA-EG-MA) polymer film obtained in the step (6) in vacuum at 60 ℃ for 12h, cutting the dried film into circular slices (the thickness of the film is 60 mu M) with the diameter d being 19mm, sucking 0.5ml of 1M LiTFSI (DOL: DME,1:1, v: v) by a dropper in an argon-filled glove box, adding the circular slices into a container in which the PAN/P (LLA-EG-MA) polymer film is placed, infiltrating for 12h, swelling and plasticizing, and sucking off the redundant electrolyte on the surface of the PAN/P (LLA-EG-MA) polymer electrolyte by using filter paper to assemble the battery.
Example 8
The invention provides a preparation method of the PAN/P (LLA-EG-MA) biological gel polymer electrolyte, which comprises the following steps:
(1) according to VCH3Cl2:VDMFMethylene Chloride (CH) was measured in a volume ratio of 4.5:1 (60 mL in total) in a corresponding volume3Cl2) Adding N, N-Dimethylformamide (DMF) solvent into a conical flask, stirring to obtain a mixed solvent, weighing 1g of PLLA powder, adding into the mixed solvent, and stirring at normal temperature until the PLLA powder is completely dissolved to obtain a PLLA solution;
(2) according to nEG:nPLLAThe molar ratio of 3:1 being measured in a corresponding volumeEthylene Glycol (EG) in terms of mSnCl2:mPLLA+EG+MA0.1: 1, weighing stannous chloride, adding the stannous chloride into the mixed suspension obtained in the step (1), and carrying out condensation reflux reaction for 8 hours at 180 ℃ under the condition of 250r/min to obtain a P (LLA-EG) light yellow transparent solution;
(3) according to nMA:nPLLAAdding a Methacrylic Acid (MA) solution into the P (LLA-EG) light yellow transparent solution obtained in the step (2) by using a separating funnel while the solution is hot, and carrying out condensation reflux reaction for 6h at 180 ℃ and 250r/min to obtain a P (LLA-EG-MA) light yellow transparent oily solution;
(4) adding absolute ethyl alcohol into the P (LLA-EG-MA) oily solution obtained in the step (3), precipitating, washing for a plurality of times, filtering, and vacuum drying at 60 ℃ for 12 hours to obtain a P (LLA-EG-MA) cross-linked product;
(5) weighing 0.2g P (LLA-EG-MA) powder, adding into 10ml DMF solvent, stirring to obtain P (LLA-EG-MA) suspension, and mixing according to mPAN:mP(LLA-EG-MA)Weighing PAN according to the mass ratio of 4.5:1, adding the PAN into the P (LLA-EG-MA) suspension, stirring the mixture at 80 ℃ at 700r/min until the PAN is completely dissolved, and continuing stirring the mixture for 12 hours;
(6) adding the PAN/P (LLA-EG-MA) solution obtained in the step (5) into a 10ml syringe, and performing electrostatic spinning under the conditions that the low voltage strength is-0.1 kV, the high voltage strength is 15kV and the injection speed is 0.085mm/min, wherein the electrospinning time is 13 h;
(7) and (3) drying the PAN/P (LLA-EG-MA) polymer film obtained in the step (6) in vacuum at 60 ℃ for 12h, cutting the dried film into circular slices (the thickness of the film is 80 mu M) with the diameter d being 19mm, sucking 0.8ml of 1M LiTFSI (DOL: DME,1:1, v: v) by a dropper in an argon-filled glove box, adding the circular slices into a container in which the PAN/P (LLA-EG-MA) polymer film is placed, infiltrating for 12h, swelling and plasticizing, and sucking off the redundant electrolyte on the surface of the PAN/P (LLA-EG-MA) polymer electrolyte by using filter paper to assemble the battery.
The above description is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above-described embodiments. Modifications and variations that may occur to those skilled in the art without departing from the spirit and scope of the invention are to be considered as within the scope of the invention.
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