Pore-forming injection type structure electrolyte, preparation method and application

Abstract

The invention provides a pore-forming injection-type structure electrolyte, a preparation method and application, and the preparation method comprises the following steps: dissolving a pore-forming agent in a first solvent to form a homogeneous solution, dropwise adding the homogeneous solution into a second solvent to precipitate the pore-forming agent, standing for aging, filtering, and drying to obtain a pore-forming precursor material; uniformly mixing the pore-forming precursor material, matrix resin and a curing agent, curing the matrix resin by adopting a gradient heating method, and removing the pore-forming precursor material to obtain a porous resin template; and injecting an electrolyte into the porous resin template by adopting a vacuum-gradient pressurization method, and obtaining the pore-forming injection type structure electrolyte after the electrolyte is fully infiltrated. The structural electrolyte prepared by the preparation method provided by the invention can realize synergistic enhancement of electrochemical performance (the conductivity can reach 2.67 * 10 <-3 > mS / cm) and mechanical performance, can efficiently cooperate with a structural energy storage material system, is suitable for the field of structural function integrated energy storage devices, and has a good industrial application prospect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of structural battery, in particular to a pore-forming injection type structural electrolyte, a preparation method and application thereof. BACKGROUND

[0002] In special equipment such as deep-sea exploration and polar scientific investigation, the structural battery needs to cope with harsh conditions such as high pressure and low temperature, and the environmental resistance and integration of the core components become the key bottleneck restricting the endurance and reliability of the equipment. The current structural battery electrolyte mostly uses a dense polymer matrix, which can provide certain mechanical support, but the ion transmission channel is limited, and the ion conductivity drops sharply at low temperature (-20℃, usually less than 10 -5 S / cm), which is difficult to meet the continuous power supply demand of the equipment; and the scheme of simply improving the ion conductivity by plasticizer will cause the mechanical properties of the matrix to decrease significantly, and cracks will easily occur under high pressure load, causing safety hazards such as electrolyte leakage.

[0003] The pore-forming injection type structural electrolyte is designed by pre-setting a porous skeleton and a functional ion conductor, which should be an ideal scheme to balance the mechanical properties and ion transmission, but the existing technology still has significant limitations. For example, the pore-forming process of the porous skeleton is difficult to accurately control the connectivity and gradient distribution of the pore channel, resulting in local aggregation or transmission blind area after the ion conductor is injected, and the mechanical properties and structural stability of the porous skeleton are also restricted due to the poor pore channel conditions. These problems make the mechanical bearing capacity and the decay rate of the electrochemical performance of the pore-forming injection type structural electrolyte in actual application much higher than the theoretical expectation, which cannot meet the demand of the special equipment for long-life and high-stability power supply system. SUMMARY

[0004] The purpose of the present application is to provide a pore-forming injection type structural electrolyte, a preparation method and application thereof to solve the problems in the background art.

[0005] The technical scheme adopted by the present application comprises: a preparation method of a pore-forming injection type structural electrolyte, which comprises:

[0006] Dissolve the pore-forming agent in the first solvent to form a homogeneous solution, drop the homogeneous solution into the second solvent to precipitate the pore-forming agent, and then stand, filter and dry to obtain a pore-forming precursor material;

[0007] Mix the pore-forming precursor material, the matrix resin and the curing agent uniformly, use the gradient heating method to cure the matrix resin, and then remove the pore-forming precursor material to obtain a porous resin template;

[0008] Use the vacuum-gradient pressurization method to inject electrolyte into the porous resin template, and after the electrolyte is fully infiltrated, a pore-forming injection type structural electrolyte is obtained.

[0009] Preferably, the pore-forming agent comprises at least one of sodium chloride, potassium chloride and sucrose, the first solvent is water, and the mass fraction of the solute in the homogeneous solution is 40-60 wt.%;

[0010] The second solvent is ethanol.

[0011] The volume ratio of the dropped homogeneous solution to the second solvent is (2-5):10.

[0012] Preferably, the preparation method further comprises the step of: performing ultrasonic dispersion treatment on the homogeneous solution, and the ultrasonic dispersion treatment is performed at a frequency of 30-100 kHz for 10-60 min.

[0013] When the homogeneous solution is dropped into the second solvent to precipitate the pore-forming agent: the homogeneous solution is added at a rate of 0.1-1 mL / min, and the second solvent is stirred at 200-1000 rpm for 10-60 min after the addition of the homogeneous solution is completed.

[0014] The standing and aging time is 6-48 h.

[0015] When the pore-forming precursor material is dried: the temperature is 40-80℃, and the time is 6-24 h.

[0016] Preferably, the matrix resin is an epoxy resin, and the curing agent comprises at least one of ethylenediamine, hexanediamine, diethylenetriamine, polyetheramine, m-phenylenediamine, triethylenetetramine, diethylaminopropylamine, 4,4'-diaminodiphenylmethane, maleic anhydride, phthalic anhydride, linoleic acid dimer and tung oil acid dimer.

[0017] Preferably, the mass ratio of the pore-forming precursor material, the matrix resin and the curing agent is (20-70):100:(5-30).

[0018] Preferably, when the matrix resin is cured by the gradient heating method: the temperature is raised at a rate of 1-5℃ / min, and the temperature is raised to 60-180℃ and then held for 2-12 h.

[0019] The method for removing the pore-forming precursor material is water washing, acid washing or heat treatment.

[0020] Preferably, the electrolyte comprises:

[0021] A base solution composed of a lithium salt and a third solvent, the third solvent is an organic solvent, and the concentration of the lithium salt in the base solution is 0.8-1.2 mol / L.

[0022] A functional additive, and the mass ratio of the functional additive to the base solution is (0.5-15):100.

[0023] Preferably, when the electrolyte is injected into the porous resin template by the vacuum-gradient pressurization method, the first gradient pressure is 0.1-0.5 MPa, the second gradient pressure is 1-3 MPa, and the third gradient pressure is 3-5 MPa, and the first gradient pressure, the second gradient pressure and the third gradient pressure are maintained for 5-30 min, respectively.

[0024] The technical scheme of the present application also includes a pore-forming injection type structure electrolyte prepared by the preparation method of the pore-forming injection type structure electrolyte.

[0025] The technical scheme of the present application also includes application of the pore-forming injection type structure electrolyte in a structure battery.

[0026] The present application has the following beneficial effects:

[0027] The present application can precisely control the morphology and particle size of the pore-forming precursor material by regulating the selection and ratio of the pore-forming agent, the first solvent and the second solvent, and by designing the dispersion process and precipitation process of the pore-forming agent, and by using the solvent replacement principle to dissolve and then precipitate the pore-forming agent; the present application can precisely control the distribution of the pore-forming precursor material in the matrix resin, and precisely control the diameter and distribution of the pores in the porous resin template and the connectivity state of the pores, by regulating the selection and ratio of the pore-forming precursor material, the matrix resin and the curing agent, and by designing the gradient temperature process; the present application can improve the distribution and flow of the electrolyte in the porous resin template, and improve the mechanical properties of the structure electrolyte; the present application can ensure the ion transport performance of the structure electrolyte by injecting the electrolyte by the vacuum-gradient pressurization method.

[0028] The preparation method is simple to operate, environmentally friendly and safe, has good process compatibility, and the prepared structure electrolyte can realize the synergistic enhancement of the electrochemical performance (the electrical conductivity can reach 2.67*10 -3 mS / cm) and the mechanical properties, can efficiently cooperate with the structure energy storage material system, is suitable for the field of structure and function integrated energy storage devices, and has good industrial application prospects. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 is an SEM image of the porous resin template prepared in Example 1 of the present application;

[0030] Figure 2 is an N2 adsorption-desorption isotherm curve of the porous resin template prepared in Example 1 of the present application;

[0031] Figure 3 is a pore size distribution graph of the porous resin template prepared in Example 1 of the present application;

[0032] Figure 4is a graph of electrochemical impedance spectrum test results of the pore injection type structure electrolyte manufactured in Example 1 of the present application;

[0033] Figure 5 is a graph of electrochemical impedance spectrum test results of the structure electrolyte manufactured in the comparative example of the present application. DETAILED DESCRIPTION

[0034] Embodiments of the present application are described in detail below.

[0035] The present application provides a pore injection type structure electrolyte, a preparation method and application thereof in a structure battery, the pore injection type structure electrolyte has a porous resin template with gradient changes in pore diameter and pore number, so that after electrolyte injection, the ion transmission efficiency of the structure electrolyte is stable, the mechanical property is good, and the structure stability is strong.

[0036] The preparation method of the pore injection type structure electrolyte provided by the embodiments of the present application comprises the following steps:

[0037] (1) dissolving the pore-forming agent in the first solvent to form a homogeneous solution, dropping the homogeneous solution into the second solvent to precipitate the pore-forming agent, standing and aging, filtering and drying to obtain a pore-forming precursor material;

[0038] (2) uniformly mixing the pore-forming precursor material, the matrix resin and the curing agent, using the gradient temperature rising method to cure the matrix resin, and then removing the pore-forming precursor material to obtain a porous resin template;

[0039] (3) injecting electrolyte into the porous resin template by vacuum-gradient pressure method, and obtaining a pore injection type structure electrolyte after the electrolyte is fully infiltrated.

[0040] In the technical solution, step (1) can precisely control the morphology and particle size of the pore-forming precursor material by controlling the selection and ratio of the pore-forming agent, the first solvent and the second solvent, and designing the dispersion process and precipitation process of the pore-forming agent; step (2) can precisely control the distribution of the pore-forming precursor material in the matrix resin, precisely control the diameter and distribution of the holes in the porous resin template, and improve the mechanical property of the structure electrolyte by controlling the selection and ratio of the pore-forming precursor material, the matrix resin and the curing agent, and designing the gradient temperature rising process; and step (3) can ensure the ion transmission performance of the structure electrolyte by injecting electrolyte by vacuum-gradient pressure method to make the electrolyte fully infiltrate.

[0041] In step (1), the pore-forming agent can be any one or more of sodium chloride, potassium chloride and sucrose, the first solvent is water, and the solute mass fraction of the homogeneous solution prepared from the pore-forming agent and the first solvent is preferably 40-60 wt%; after the preparation of the homogeneous solution, it needs to be subjected to ultrasonic dispersion treatment, and through the cavitation effect of ultrasonic waves, local high pressure and micro-jet are generated to strongly disperse the pore-forming agent agglomerates, so that they are uniformly dispersed in water and form a kinetic stable suspension system, providing uniform nucleation sites for the subsequent precipitation of the pore-forming agent.

[0042] The conditions for the above ultrasonic dispersion treatment are preferably as follows: the frequency is 30-100 kHz, and the time length is 10-60 min.

[0043] In step (1), the second solvent is ethanol, and when the homogeneous solution is dropped into the second solvent to precipitate the pore-forming agent: the homogeneous solution is added at a speed of 0.1-1 mL / min, and the volume ratio of the dropped homogeneous solution to the second solvent is preferably (2-5):10; the second solvent is stirred at 200-1000 rpm for 10-60 min after the addition of the homogeneous solution is completed. In the above scheme, the solubility difference of the pore-forming agent in water and ethanol is utilized, the homogeneous solution (i.e. the aqueous solution of the pore-forming agent) is slowly added to the vigorously stirred ethanol to induce the change of solvent polarity / dielectric constant, so that the pore-forming agent is precipitated under controllable supersaturation, in addition, ethanol can also induce the formation of spherical structure by changing the crystal growth habit (inhibiting specific crystal face) or reducing the interfacial tension.

[0044] After the addition of the homogeneous solution is completed, the mixture of the homogeneous solution and the second solvent should be left to stand for a period of time, and the standing time is preferably 6-48 h to allow the particles of the pore-forming precursor material to grow and stabilize fully.

[0045] The above ultrasonic dispersion treatment, the addition speed of the homogeneous solution, the stirring speed of the second solvent, the ratio of the homogeneous solution to the second solvent, and the standing time are controlled to realize the precise control of the growth rate, morphology and particle size of the pore-forming precursor material.

[0046] After the pore-forming precursor material grows and stabilizes fully, it is collected by filtration and dried, the filtration method is preferably vacuum filtration, and the drying method is preferably vacuum drying, the temperature during drying should be controlled at 40-80℃, and the time length should be controlled at 6-24 h.

[0047] In step (2), the base resin can be an epoxy resin, specifically any one or more of the following materials with different epoxy equivalent weights and viscosities: EP-301, EP-360, EP-365, E-44, E-51, E-54, E-57, E-58, EP-1001, YD-128, ER2221 and EP828AB; the curing agent can be any one or more of ethylenediamine, hexanediamine, diethylenetriamine, polyetheramine, m-phenylenediamine, triethylenetetramine, diethylaminopropylamine, 4,4'-diaminodiphenylmethane, maleic anhydride, phthalic anhydride, linoleic acid dimer and tung oil acid dimer; and the mass ratio of the pore-forming precursor material, the base resin and the curing agent is preferably (20-70): 100: (5-30).

[0048] Before curing the base resin by the gradient temperature method, the pore-forming precursor material should be uniformly dispersed in the base resin to avoid agglomeration of the pore-forming precursor material or stratification of the base resin, and ensure the stability of the mixed system. To this end, the mixture is stirred by a high-speed disperser, preferably at a stirring speed of 500-2000 rpm for 10-60 min until uniform mixing.

[0049] The material mixed by the high-speed disperser contains a large number of bubbles. To avoid bubbles hindering the uniform combination of the pore-forming precursor material and the base resin, and thus affecting the distribution of the pores in the final porous resin template, the material containing bubbles should be subjected to vacuum degassing before curing the base resin by the gradient temperature method. The method is as follows: vacuum is drawn at a pressure of -0.08 to -0.1 MPa with auxiliary low-speed stirring at 100-500 rpm for 10-60 min until no obvious bubbles are present in the material.

[0050] When curing the base resin by the gradient temperature method: the degassed material is poured into a pre-prepared mold, and the system is heated to 60-180°C at a heating rate of 1-5°C / min, and then held for 2-12 h to cure the base resin. During operation, adaptive adjustments should be made within the range of the above process parameters according to different base resin and curing agent formulations.

[0051] The gradient temperature process can improve the compactness of the internal structure of the base resin, and a differential phase separation process is induced by the temperature gradient: in the process of gradient temperature, the low temperature of 40-80°C can promote the resin system to quickly undergo thermal-induced phase separation, thereby forming a slightly smaller pore size. In this temperature range, the resin system and the pore-forming precursor material will separate into resin-rich and resin-poor phases due to the difference in compatibility, forming an initial phase separation structure that determines the primary pore (nano / micron) morphology of the material. The slower the heating rate in this process, the more complete the phase separation, and the more uniform the microporous structure formed. Subsequently, the temperature is raised to the curing reaction temperature range of the base resin, and the medium temperature of 80-120°C makes the curing reaction start and accelerate comprehensively, the polymer chains crosslink to form a three-dimensional network, locking the phase separation structure formed at the low temperature stage, and realizing the gradient transition of the pore size through continuous temperature change. By adjusting the heating rate at this stage, the curing rate can be adjusted to control the compactness and mechanical strength of the pore wall. Finally, continue to raise the temperature to 150°C and above, the material forms a slightly larger pore size due to the rapid movement of molecular chains and slow phase separation speed, and prepares for the subsequent pore-forming precursor material dissolution and elution step. After the base resin is completely cured, the pore-forming precursor material embedded in it is removed by water washing, acid washing or heat treatment, thereby forming a three-dimensional interconnected pore structure with gradient change in pore size in the base resin. Finally, a porous resin template with excellent porosity and mechanical properties is obtained, which can meet the dual demands of power supply performance and load bearing performance of structural batteries after injecting electrolyte.

[0052] Based on full consideration of the migration behavior and kinetic characteristics of ions in different regions of structural batteries or composite electrolyte systems, the porous resin template obtained by the above technical solution has a pore structure with a gradient change in pore size from the surface layer to the inside, with the number of pores gradually increasing. On the one hand, this pore structure builds a continuous and unobstructed ion transport path, with small ion migration resistance and stable transmission efficiency, which can adapt to the demand for rapid ion transmission after injecting electrolyte. Specifically, the pore structure with gradient change in pore size can precisely control the surface energy distribution by making the large pore end hydrophobic and the small pore end hydrophilic. The large pore end realizes spontaneous directional rapid infiltration and liquid locking of the electrolyte, ensuring complete filling of the pore channel, and the small pore end prevents drying through capillary action, which can well adapt to the volume change of the electrode and improve the cycle stability. The large pore end provides a low tortuosity channel to accelerate ion diffusion, which can quickly transfer reactants to active sites to improve material transport efficiency. The small pore end enhances interfacial charge exchange through high specific surface area, which not only reduces concentration polarization and impedance, but also inhibits dendrite growth, provides high-density active sites, and promotes complete reaction, thereby significantly improving reaction efficiency. In addition, the optimized gradient pore design can uniformly distribute ion flow, reduce local current density, significantly inhibit side reactions, and improve the electrochemical stability of the structural electrolyte.

[0053] On the other hand, the pore structure can significantly improve the mechanical properties of the structural electrolyte in combination with a special matrix resin material. Specifically, the structural transition zone formed by the gradient change of the pore size can effectively reduce local stress concentration and enhance the overall structural stability of the structural electrolyte. The large pore side of the pore can withstand initial impact and buffer the volume change of the electrolyte, while the small pore side provides stable support to maintain the mechanical strength of the structural electrolyte, achieving stress self-adaptive distribution and effectively preventing local stress concentration and uneven stress distribution from causing resin cracking and failure, thereby significantly improving the compression resistance of the material. In combination with the special matrix resin material that can resist chemical corrosion of both aqueous and organic electrolytes, the compatibility of the porous resin template with the electrolyte is improved, i.e., both aqueous and organic systems can be stably combined, reducing the dissolution or degradation of the matrix resin, effectively avoiding solidification failure caused by poor material matching between the electrolyte and the matrix resin, and enabling the structural electrolyte to have excellent mechanical strength, effectively resisting deformation under external load, reducing the performance degradation risk caused by battery structure deformation, enhancing the structural durability of the battery during long-term cycling, alleviating the volume expansion and contraction effect caused by repeated charging and discharging, further maintaining good contact between internal components, reducing the possibility of interface failure, and improving the stability and reliability of the overall electrochemical system.

[0054] More specifically, the water washing process for removing the pore-forming precursor material is as follows: water washing 2-5 times, with water changed every 4 hours. The acid washing process for removing the pore-forming precursor material is as follows: acid washing concentration is 0.1-2 mol / L, and the acid washing solution can be 5%-10% dilute sulfuric acid, dilute hydrochloric acid, or dilute acetic acid. The heat treatment process for removing the pore-forming precursor material is as follows: temperature 200-600°C, time 1-6 hours.

[0055] In step (3), the electrolyte should be prepared in an argon-protected glove box (water and oxygen content <0.1 ppm). The electrolyte specifically includes a base solution and functional additives. The base solution is composed of a lithium salt and a third solvent, preferably an organic solvent. The concentration of the lithium salt in the base solution is 0.8-1.2 mol / L. The mass ratio of the functional additives to the base solution is (0.5-15):100.

[0056] The lithium salt can be any one of lithium hexafluorophosphate, lithium bis(trifluoromethanesulfonyl)imide, lithium tetrafluoroborate, lithium bis(oxalato)borate, lithium fluoroethylene carbonate, lithium bisfluorosulfonylimide, lithium trifluoromethylsulfonate, lithium chloride, lithium bromide, lithium difluoro(oxalato)borate, and lithium difluorophosphate.

[0057] The third solvent is preferably an organic solvent, and can specifically be any one or more of vinyl carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, ethyl acetate, methyl propionate, methyl butyrate, 1,3-dioxolane, dimethoxyethane, sulfolane, acetonitrile, and fluorinated carbonate (such as FEC, DFEC). The third solvent should be degassed before use. The molecular sieve is dehydrated for 48 h, and the moisture content is ≤20 ppm.

[0058] The functional additives can include any one or more of the following: film-forming additives - fluorinated vinyl carbonate, vinylene carbonate, overcharge protection additives - biphenyl, dimethoxybenzene, flame retardant additives - trimethyl phosphate, triphenyl phosphate, antioxidant additives - butanedinitrile, hexanedinitrile, additives for improving low-temperature performance - 1,3-propane sulfolane, additives for improving high-temperature stability - ethylene sulfate, polyethylene glycol dimethyl ether (PEGDME, Mn = 500) for improving the wettability between the electrolyte and the porous resin template, and silane coupling agents [such as γ-(methacryloyloxy)propyltrimethoxysilane] for enhancing the interfacial bonding force between the electrolyte and the porous resin template.

[0059] When preparing the base solution, the lithium salt should be slowly added to the third solvent, and magnetic stirring or ultrasonic treatment should be performed to quickly and uniformly disperse the lithium salt. The stirring speed can be controlled at 500 rpm, the ultrasonic power can be controlled at 200 W, and the intermittent working mode of 5 min of ultrasonic treatment and 2 min of stopping should be adopted for 30 min until the lithium salt is completely dissolved.

[0060] In step (3), the specific operation of injecting electrolyte into the porous resin template by vacuum-gradient pressurization method includes: (3.1) placing the porous resin template in a vacuum drying box, drying at 80℃ for 12h to completely remove the residual moisture and impurities in the pores, avoiding the adverse effects on the chemical stability and ion transport performance of the electrolyte, then placing it correctly in a special mold and ensuring good sealing to avoid leakage in subsequent operations, then connecting the injection port and exhaust port; (3.2) filtering the prepared electrolyte through a 0.22μm filter membrane to remove small particles and avoid blocking the pores of the porous resin template or becoming an interference site for electrochemical reaction, then using ultrasonic-vacuum cooperation to degas to prevent bubbles from being left in the pores to form ion transport blind area in the subsequent injection process, and using it after ensuring that there are no bubbles in the electrolyte; (3.3) starting the vacuum pump to vacuum the mold and pipeline to completely remove the air in the porous resin template, slowly injecting the electrolyte at the first gradient pressure under the condition of maintaining vacuum, gradually increasing the injection pressure to the second gradient pressure as the electrolyte gradually fills the porous resin template, promoting the electrolyte to overcome the capillary resistance and deeply fill the small gap area, when it is close to complete filling, further increasing the injection pressure to the third gradient pressure and keeping it for a certain period of time, ensuring that the electrolyte is fully infiltrated and compacted, then stopping the pressurization and closing the vacuum pump and injection pump, and standing for 12-24h to make the electrolyte fully infiltrate, and the pore-forming injection type structure electrolyte is obtained.

[0061] The purpose of injecting electrolyte into the porous resin template by vacuum-gradient pressurization method is to promote the electrolyte to fully compact the pores, eliminate local vacancies, realize the close combination of the electrolyte and the porous resin template, and ensure the formation of a continuous and uninterrupted ion transport network, providing protection for the structural electrolyte to have high mechanical support and excellent electrochemical performance. Preferably, the first gradient pressure is 0.1-0.5MPa, the second gradient pressure is 1-3MPa, and the third gradient pressure is 3-5MPa, and the first gradient pressure, the second gradient pressure and the third gradient pressure are kept for 5-30min respectively.

[0062] The preparation method of the above-mentioned pore-forming injection type structure electrolyte is simple, green and safe in process, has good process compatibility, and the prepared structure electrolyte can realize the synergistic enhancement of electrochemical performance (the conductivity can reach 2.67×10 -3 mS / cm) and mechanical performance, can efficiently synergize with the structure energy storage material system, is suitable for the field of structural and functional integrated energy storage devices, and has good industrial application prospect.

[0063] The following are specific examples and comparative examples of the present application.

[0064] Example 1

[0065] (1) Dissolve sodium chloride (pore-forming agent) in deionized water (first solvent) to form a 50 wt% homogeneous solution, and place the homogeneous solution in an ultrasonic cleaner for ultrasonic dispersion treatment at a frequency of 100 Hz for 30 min.

[0066] Stir anhydrous ethanol (second solvent) at 1000 rpm, and drop the treated homogeneous solution into the anhydrous ethanol at a rate of 0.1-1 mL / min until the volume ratio of the dropped homogeneous solution to the anhydrous ethanol is 2:10. Continue stirring the mixture for 30 min after the homogeneous solution is completely dropped, and then let it stand for aging for 24 h to allow the sodium chloride particles to grow and stabilize. Finally, vacuum filtration is performed, and the filter cake is vacuum dried at 60°C for 24 h to obtain the pore-forming precursor material.

[0067] (2) Take the pore-forming precursor material, E-51 (matrix resin), and ethylenediamine (curing agent) in a mass ratio of 50:100:30, and stir them in a high-speed disperser at a speed of 1000 rpm for 30 min until the materials are uniformly mixed.

[0068] Perform vacuum degassing treatment on the uniformly mixed materials: vacuumize at a pressure of -0.1 MPa with low-speed stirring at 100 rpm for 60 min until no obvious bubbles are present in the materials.

[0069] Pour the degassed materials into a pre-prepared mold, and use the gradient temperature rising method to cure the matrix resin. Specifically, raise the temperature of the system to 100°C at a rate of 3°C / min, and then keep the temperature for 12 h.

[0070] After the matrix resin is cured and formed, remove the pore-forming precursor material embedded in the matrix resin by water washing. The water washing is performed 5 times, and the water is changed every 4 h. Finally, a porous resin template is obtained.

[0071] (3) In an argon glove box (both the water and oxygen contents are <0.1 ppm), slowly add lithium bis(trifluoromethanesulfonyl)imide (lithium salt) into the third solvent to prepare a basic solution with a lithium salt concentration of 0.8 mol / L, using magnetic stirring at a speed of 500 rpm in combination with ultrasonic treatment. The third solvent includes ethylene carbonate, dimethyl carbonate, and methyl ethyl carbonate in a volume ratio of 1:1:1, and the third solvent should be dehydrated by molecular sieves for 48 h before use until the water content is ≤20 ppm. The ultrasonic power is controlled at 200 W, and the ultrasonic treatment is performed in an intermittent mode of 5 min on and 2 min off for 30 min until the lithium salt is completely dissolved.

[0072] Mix the functional additive, polyethylene glycol dimethyl ether (PEGDME, Mn=500), and the basic solution in a mass ratio of 1:100 to obtain an electrolyte. ​

[0073] The porous resin template is placed in a vacuum drying oven, dried at 80°C for 12h to completely remove the residual moisture and impurities in the channel, correctly placed in a special mold, and ensure good sealing to avoid leakage in subsequent operations, then connect the injection port and exhaust port; The prepared electrolyte is filtered through a 0.22μm filter membrane to remove small particles, then degassed by ultrasonic-vacuum to ensure that there are no bubbles in the electrolyte; Start the vacuum pump, vacuumize the mold and pipeline to completely exhaust the air in the porous resin template, slowly inject the electrolyte with the first gradient pressure using the injection pump, gradually increase the injection pressure to the second gradient pressure as the electrolyte gradually fills the porous resin template, promote the electrolyte to overcome the capillary resistance and deeply fill the small gap area, when it is close to complete filling, further increase the injection pressure to the third gradient pressure and keep it for a certain time, ensure that the electrolyte is fully infiltrated and compacted, stop the pressure and close the vacuum pump and injection pump, stand for 24h, so that the electrolyte is completely infiltrated, and the pore-forming injection structure electrolyte is obtained.

[0074] The first gradient pressure is 0.2MPa, the second gradient pressure is 2MPa, and the third gradient pressure is 3MPa. The first gradient pressure, the second gradient pressure, and the third gradient pressure are kept for 30min respectively.

[0075] Example 2

[0076] (1) Dissolve sucrose (pore-forming agent) in deionized water (first solvent) to form a homogeneous solution of 40wt%, and place the homogeneous solution in an ultrasonic cleaner for ultrasonic dispersion treatment at a frequency of 50Hz for 60min.

[0077] Stir the absolute ethanol (second solvent) at 700rpm, and drop the treated homogeneous solution into the absolute ethanol at a speed of 0.1-1mL / min, until the volume ratio of the dropped homogeneous solution to the absolute ethanol is 3:10. After the homogeneous solution is added, continue to stir the mixture for 60min, then stand for 12h to allow the sucrose particles to grow and stabilize. Finally, vacuum filter the filter cake, and vacuum dry the filter cake at 80°C for 20h to obtain the pore-forming precursor material.

[0078] (2) Take the pore-forming precursor material, E-51 (matrix resin), and polyetheramine (curing agent) in a mass ratio of 70:100:30, and stir in a high-speed disperser at a speed of 700rpm for 60min until the materials are uniformly mixed.

[0079] Vacuum degassing treatment is performed on the uniformly mixed materials: vacuumize at a pressure of-0.08MPa and assist with low-speed stirring at 100rpm for 60min until there are no obvious bubbles in the materials.

[0080] The defoamed material is poured into a pre-prepared mold, and the matrix resin is cured by using a gradient heating method. The specific process is as follows: after the system is heated to 80℃ at a heating rate of 5℃ / min, it is kept for 2h.

[0081] After the matrix resin is cured and formed, the pore-forming precursor material embedded in the matrix resin is removed by water washing. The water washing is performed 5 times, and the water is changed every 4h. Finally, a porous resin template is obtained.

[0082] (3) In an argon glove box (water and oxygen content <0.1 ppm), lithium bisfluorosulfonylimide (lithium salt) is slowly added to the third solvent, and a 1 mol / L lithium salt base solution is prepared by using 500 rpm magnetic stirring combined with ultrasonic. The third solvent includes ethylene carbonate, dimethyl carbonate and methyl ethyl carbonate in a volume ratio of 1:2:2, and the third solvent should be dehydrated by molecular sieves before use. The molecular sieves are dehydrated for 48h until the water content is ≤20ppm. The ultrasonic power is controlled at 200W and the intermittent working mode of ultrasonic for 5min and stop for 2min is used for 30min until the lithium salt is completely dissolved.

[0083] The functional additive γ-(methacryloyloxy)propyl trimethoxysilane and the base solution are mixed in a mass ratio of 0.5:100 to obtain an electrolyte.

[0084] The porous resin template is placed in a vacuum drying oven and dried at 80℃ for 12h to completely remove the residual water and impurities in the pores. It is correctly placed in a special mold and sealed well to avoid leakage in subsequent operations. Then the injection port and exhaust port are connected. The prepared electrolyte is filtered through a 0.22μm filter membrane to remove small particles, and then ultrasonic-vacuum synergistic defoaming is used to ensure that there are no bubbles in the electrolyte. Start the vacuum pump to vacuum the mold and pipeline to completely exhaust the air in the porous resin template. Under the condition of maintaining vacuum, use the injection pump to start slowly injecting the electrolyte at the first gradient pressure. As the electrolyte gradually fills the porous resin template, gradually increase the injection pressure to the second gradient pressure to promote the electrolyte to overcome the capillary resistance and deeply fill the small gap area. When it is close to complete filling, further increase the injection pressure to the third gradient pressure and keep it for a certain time. After ensuring that the electrolyte is fully infiltrated and compacted, stop the pressure and turn off the vacuum pump and injection pump. Let it stand for 24h to make the electrolyte completely infiltrate, and a pore-forming injection structure electrolyte is obtained.

[0085] The first gradient pressure is 0.5MPa, the second gradient pressure is 3MPa, and the third gradient pressure is 5MPa. The first gradient pressure, the second gradient pressure and the third gradient pressure are kept for 20min respectively.

[0086] Example 3

[0087] (1) Dissolve sucrose (pore-forming agent) in deionized water (first solvent) to form a 50wt% homogeneous solution. Place the homogeneous solution in an ultrasonic cleaner and ultrasonically disperse it at a frequency of 30Hz for 60min.

[0088] Anhydrous ethanol (second solvent) was stirred at 1000 rpm. The prepared homogeneous solution was added dropwise to the anhydrous ethanol at a rate of 0.1-1 mL / min until the volume ratio of the added homogeneous solution to anhydrous ethanol was 4:10. After the homogeneous solution was added, the mixture was stirred for 60 min and then allowed to stand for 48 h to allow the sucrose particles to grow fully and stabilize. Finally, the mixture was vacuum filtered and the filter cake was vacuum dried at 80 °C for 24 h to obtain the pore-forming precursor material.

[0089] (2) Take the pore-forming precursor material, E-51 (matrix resin) and polyetheramine (curing agent) in a mass ratio of 20:100:30, and stir them in a high-speed disperser at a speed of 1000 rpm for 60 minutes until the materials are evenly mixed.

[0090] Vacuum degassing treatment is performed on the uniformly mixed material: vacuum is drawn under a pressure of -0.1MPa and low-speed stirring at 200rpm is performed for 60min until there are no obvious bubbles in the material.

[0091] The degassed material is poured into a pre-prepared mold, and the matrix resin is cured using a gradient heating method. The specific process is as follows: the system is heated to 60°C at a heating rate of 3°C / min, and then kept at that temperature for 12 hours.

[0092] After the matrix resin is cured and molded, the pore-forming precursor material embedded in the matrix resin is removed by water washing. The water washing is performed 5 times, and the water is changed every 4 hours to finally obtain a porous resin template.

[0093] (3) In an argon-protected glove box (water and oxygen content < 0.1 ppm), lithium hexafluorophosphate (lithium salt) is slowly added to the third solvent, and a basic solution with a lithium salt concentration of 1 mol / L is prepared by magnetic stirring at 500 rpm combined with ultrasound; wherein, the third solvent includes ethylene carbonate, dimethyl carbonate and ethyl methyl carbonate in a volume ratio of 3:4:3, and the third solvent should be tested before use. Molecular sieve dewatering for 48 hours until moisture content ≤20ppm; ultrasonic power controlled at 200W and using an intermittent working mode of 5 minutes of ultrasonication followed by 2 minutes of rest, for 30 minutes, until lithium salt is completely dissolved.

[0094] The functional additive, γ-(methacryloyloxy)propyltrimethoxysilane, and the base solution were mixed at a mass ratio of 0.5:100 to obtain the electrolyte.

[0095] The porous resin template is placed in a vacuum drying oven and dried at 80°C for 12 hours to thoroughly remove residual moisture and impurities from the pores. It is then correctly placed in a special mold, ensuring a good seal to prevent leakage during subsequent operations. The injection port and vent are then connected. The prepared electrolyte is filtered through a 0.22μm filter membrane to remove microparticles, followed by ultrasonic-vacuum degassing to ensure the electrolyte is free of air bubbles before use. The vacuum pump is started to evacuate the mold and pipes to completely remove air from the porous resin template. While maintaining the vacuum, the electrolyte is slowly injected using an injection pump at the first gradient pressure. As the electrolyte gradually fills the porous resin template, the injection pressure is gradually increased to the second gradient pressure to help the electrolyte overcome capillary resistance and deeply fill the micro-gaps. When it is nearly completely filled, the injection pressure is further increased to the third gradient pressure and maintained for a certain period of time to ensure that the electrolyte is fully penetrated and compacted. After that, the pressurization is stopped and the vacuum pump and injection pump are turned off. The template is left to stand for 24 hours to allow the electrolyte to fully impregnate it, thus obtaining a porous injection-type electrolyte.

[0096] Wherein: the first gradient pressure is 0.1 MPa, the second gradient pressure is 1 MPa, and the third gradient pressure is 3 MPa. The first gradient pressure, the second gradient pressure, and the third gradient pressure are maintained for 10 min each.

[0097] Comparative Example

[0098] Compared with Example 1, the only difference is that in step (2) of the comparative example, the matrix resin is cured by standing at room temperature for 48 hours.

[0099] The porous resin template prepared in step (2) of Example 1 was characterized by SEM, subjected to N2 adsorption-desorption isotherm testing, and tested for the pore size distribution of the Bio-Rad-Joyner-Halenda resin. The results showed that the porous resin template was subjected to SEM characterization, N2 adsorption-desorption isotherm testing, and Bio-Rad-Joyner-Halenda pore size distribution. Figures 1-3 The result. (By) Figure 2 It can be determined that the specific surface area of ​​the porous resin template is 85.3 m². 2 g -1 Corresponding to Type IV isotherms in the IUPAC classification, the hysteresis loop indicates the presence of numerous mesoporous structures in the material. Figure 1 as well as Figure 3 It can be observed that the pore size is mainly mesopores distributed between 4-10 nm, and the pore size gradually decreases and the number of pores gradually increases from the surface of the porous resin template inward.

[0100] The symmetrical blocked electrode batteries assembled with the structural electrolytes prepared in Example 1 and the comparative example were subjected to electrochemical impedance spectroscopy tests using an electrochemical workstation, and the results were obtained.Figures 4-5 The results are shown in Table 1. Figure 4 The ionic conductivity of the structure electrolyte prepared in Example 1 was 2.67 x 10 -3 mS / cm, Figure 5 The ionic conductivity of the structure electrolyte prepared in Comparative Example 1 was 2.9 x 10 -4 mS / cm.

[0101] It should be understood that the above detailed description and specific examples, which are presented only by way of illustration and not of limitation, are merely exemplary and explanatory and are not intended to limit the application. Any modification, equivalent replacement, improvement, etc. made without departing from the spirit and scope of the present application should be included in the scope of the present application. In addition, the appended claims of the present application are intended to cover all changes and modifications falling within the scope and boundary of the claims, or equivalents of such scope and boundary.

Claims

1. A method for preparing a porous injection-molded structure electrolyte, characterized by, The method comprises the following steps: The pore-forming agent is dissolved in a first solvent to form a homogeneous solution, the homogeneous solution is dropped into a second solvent to precipitate the pore-forming agent, and the pore-forming agent is removed by aging, filtering and drying to obtain a pore-forming precursor material; The pore-forming precursor material, a matrix resin and a curing agent are uniformly mixed, the matrix resin is cured by using a gradient temperature rising method, and then the pore-forming precursor material is removed to obtain a porous resin template; An electrolyte is injected into the porous resin template by using a vacuum-gradient pressure method, and the electrolyte is fully infiltrated to obtain a pore-forming injection type structure electrolyte.

2. The method of claim 1, wherein, The pore-forming agent comprises at least one of sodium chloride, potassium chloride and sucrose, the first solvent is water, and the mass fraction of the solute in the homogeneous solution is 40-60 wt%. The second solvent is ethanol. The volume ratio of the dropped homogeneous solution to the second solvent is (2-5):

10.

3. The method of claim 2, wherein the pore-generating injection of the structure electrolyte is performed by a method comprising: The homogeneous solution is subjected to ultrasonic dispersion treatment, and the ultrasonic dispersion treatment is performed at a frequency of 30-100 kHz for 10-60 min. When the homogeneous solution is dropped into the second solvent to precipitate the pore-forming agent, the homogeneous solution is added at a speed of 0.1-1 mL / min, and the second solvent is stirred at 200-1000 rpm for 10-60 min after the addition of the homogeneous solution is completed. The aging time is 6-48 h. When the pore-forming precursor material is dried, the temperature is 40-80 ℃, and the time is 6-24 h.

4. The method of claim 1-3, wherein, The matrix resin is an epoxy resin, and the curing agent comprises at least one of ethylenediamine, hexanediamine, diethylenetriamine, polyetheramine, m-phenylenediamine, triethylenetetramine, diethylaminopropylamine, 4,4'-diaminodiphenylmethane, maleic anhydride, phthalic anhydride, linoleic acid dimer and tung oil acid dimer.

5. The method of claim 4, wherein the pore-generating injection of the structure electrolyte is performed by a method comprising: The mass ratio of the pore-forming precursor material, the matrix resin and the curing agent is (20-70):100:(5-30).

6. The method of claim 4, wherein the pore-generating injection of the structure electrolyte is performed by a method comprising: When the matrix resin is cured by using the gradient temperature rising method, the temperature is raised at a speed of 1-5 ℃ / min, the temperature is raised to 60-180 ℃, and then the temperature is kept for 2-12 h. The pore-forming precursor material is removed by water washing, acid washing or heat treatment.

7. The method of claim 1-3, 5-6, wherein the electrolyte solution is characterized by a pH of 2-5. The method comprises the following steps: A base solution is prepared from a lithium salt and a third solvent, the third solvent is an organic solvent, and the concentration of the lithium salt in the base solution is 0.8-1.2 mol / L; A functional additive, and the mass ratio of the functional additive to the base solution is (0.5-15):

100.

8. The method of claim 7, wherein the pore-generating injection of the structure electrolyte is performed by a method comprising: When the electrolyte is injected into the porous resin template by using the vacuum-gradient pressure method, the first gradient pressure is 0.1-0.5 MPa, the second gradient pressure is 1-3 MPa, and the third gradient pressure is 3-5 MPa, and the first gradient pressure, the second gradient pressure and the third gradient pressure are kept for 5-30 min, respectively.

9. A pore-generating, injection-molded structure electrolyte, characterized by The pore-forming injection type structure electrolyte is prepared by using the method of any one of claims 1-8.

10. The pore-forming injection type structure electrolyte of claim 9 is applied to a structural battery.

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