A composite gel electrolyte based on calixarene filler and its in-situ preparation method

Abstract

This invention relates to a calixarene-based composite gel electrolyte and its in-situ preparation method, comprising the following steps: S1, reacting polyethylene glycol with isocyanate methacrylate under a catalyst to undergo a carbamate addition reaction to obtain polyethylene glycol-isocyanate methacrylate; S2, mixing polyethylene glycol-isocyanate methacrylate, acrylate, calixarene, and electrolyte, adding an initiator to initiate a free radical polymerization crosslinking reaction between polyethylene glycol-isocyanate methacrylate and acrylate, forming a three-dimensional crosslinked network encapsulating the electrolyte and calixarene, thus obtaining the calixarene-based composite gel electrolyte. This invention can significantly improve the lithium-ion transference number and ionic conductivity of the composite gel electrolyte, enabling the electrolyte to maintain excellent long-term cycle stability under high-load battery systems, providing a reliable electrolyte solution for the industrialization of high-safety, high-energy-density lithium metal batteries.

Description

Technical Field

[0001] This invention relates to the field of energy storage technology, and more specifically to a composite gel electrolyte based on calixarene filler and its in-situ preparation method. Background Technology

[0002] With the rapid development of the global new energy industry, lithium-ion batteries, with their high energy density, excellent cycle performance and environmental friendliness, have become the core energy storage device in portable electronic devices (such as smartphones and laptops), electric vehicles and large-scale energy storage systems, playing a key supporting role in promoting the transformation of the energy structure.

[0003] However, the liquid electrolytes (mainly composed of lithium salts, organic solvents, and additives) commonly used in current commercial lithium-ion batteries pose significant safety hazards: organic solvents are highly volatile and flammable, and are prone to leakage, combustion, or even explosion under overcharge, over-discharge, or high-temperature conditions, severely limiting the further application of lithium-ion batteries in scenarios requiring high energy density and high safety (such as long-range electric vehicles and large-scale energy storage power stations). Therefore, developing solid-state electrolytes that combine high safety and high electrochemical performance has become a research hotspot and core breakthrough direction in the field of lithium-ion batteries in recent years.

[0004] In the research branch of solid-state electrolytes, gel electrolytes (GPEs) have become a preferred solution for balancing battery safety and electrochemical performance due to their combination of the high ionic conductivity of liquid electrolytes and the low leakage risk and high structural stability of solid-state electrolytes. This has made them an important technological path in the industrialization of solid-state electrolytes. To further improve the lithium-ion transport efficiency in gel electrolytes and address issues such as low ionic conductivity and insufficient lithium-ion transference number, researchers generally modify the electrolyte system by introducing functional fillers, utilizing the interaction between the filler and electrolyte components to regulate ion migration behavior. Among these, calixarenes (CAs) exhibit significant potential in selectively conducting lithium ions and inhibiting anion migration due to their unique hollow cage-like cavity structure and excellent host-guest recognition ability. Theoretically, they can effectively increase the lithium-ion transference number and optimize the electrochemical performance of the electrolyte.

[0005] Although calixarenes have theoretical advantages in ion regulation, their feasibility as a gel electrolyte filler in practical lithium metal battery systems has not been fully verified and still faces multiple technical challenges. On the one hand, existing research is mostly at the stage of basic performance characterization, lacking long-term cycle stability data of calixarene-based composite electrolytes under high current density and high load electrode conditions, which cannot support their practical application requirements. On the other hand, even if functional molecules (including calixarenes) are introduced into polymer matrices (such as polyethylene glycol) to construct composite electrolytes, it is still difficult to simultaneously achieve the three major goals of "increasing lithium ion transference number, constructing a stable electrolyte-lithium metal interface, and inhibiting lithium dendrite growth". Although some solutions can improve ion conduction efficiency, they are prone to low-temperature performance degradation due to excessively high crystallinity of the polymer matrix, or lithium dendrite puncture due to poor interface compatibility, ultimately shortening the battery cycle life. Summary of the Invention

[0006] To address the safety hazards of leakage and combustion in existing liquid electrolytes, as well as the low ion conduction efficiency, unstable interface, and short cycle life of gel electrolytes, this invention aims to provide a composite gel electrolyte based on calixarene filler and its in-situ preparation method.

[0007] The in-situ preparation method of the calixarene-based composite gel electrolyte according to the present invention includes the following steps: S1, polyethylene glycol and isocyanate methacrylate undergo a carbamate addition reaction under the action of a catalyst to obtain polyethylene glycol-isocyanate methacrylate; S2, polyethylene glycol-isocyanate methacrylate, acrylate, calixarene and electrolyte are mixed, and an initiator is added to initiate a free radical polymerization crosslinking reaction between polyethylene glycol-isocyanate methacrylate and acrylate to form a three-dimensional crosslinked network encapsulating electrolyte and calixarene, thereby obtaining the calixarene-based composite gel electrolyte.

[0008] In a preferred embodiment, in step S1, the molar ratio of polyethylene glycol to isocyanate methacrylate is 1:2.1~2.4.

[0009] In a preferred embodiment, in step S1, the catalyst is at least one of dibutyltin dilaurate (DBTDL), stannous octoate, and polyurethane organotin catalyst T9.

[0010] In a preferred embodiment, in step S1, the amount of catalyst used is 3-12 mol%, for example 6-10 mol%, based on the amount of polyethylene glycol.

[0011] In a preferred embodiment, in step S1, the addition reaction is carried out at 60-80°C.

[0012] In a preferred embodiment, in step S2, the acrylate is one of polyethylene glycol diacrylate, ethylene glycol dimethacrylate, polyethylene glycol methacrylate, ethoxylated trimethylolpropane triacrylate, and ethoxylated pentaerythritol tetraacrylate.

[0013] In a preferred embodiment, in step S2, the calixarene is one of calix-4 aromatics, calix-6 aromatics, calix-8 aromatics, tert-butylcalix-4 aromatics, tert-butylcalix-5 aromatics, tert-butylcalix-6 aromatics, tert-butylcalix-8 aromatics, 4-sulfonic acid calixarene, 4-tert-butylthiacalix-4 aromatics, 4-tert-butylthiacalix-6 aromatics, and 4-tert-butylthiacalix-8 aromatics.

[0014] In a preferred embodiment, in step S2, the solvent in the electrolyte is one of propylene carbonate, diethyl carbonate, dimethyl carbonate, ethylene carbonate, fluoroethylene carbonate, dioxolane, and dimethyl ether.

[0015] In a preferred embodiment, in step S2, the solid content in the free radical polymerization crosslinking reaction system is 8-20%.

[0016] The present invention also relates to a calixarene-based composite gel electrolyte obtained by the above-described in-situ preparation method.

[0017] The in-situ preparation method of this invention obtains a polyethylene glycol-isocyanate prepolymer containing polymerizable double bonds through a carbamate addition reaction of polyethylene glycol and isocyanate methacrylate. Then, an initiator induces free radical polymerization and crosslinking with multifunctional acrylates, forming a three-dimensional crosslinked network in situ encapsulating the electrolyte and calixarenes. This effectively avoids the safety hazards of leakage and combustion associated with traditional liquid electrolytes. Furthermore, the size sieving effect of calixarenes repels anions and promotes selective lithium-ion transport, while multiple hydrogen bonds disrupt the crystallinity of the polyethylene glycol matrix. It promotes lithium salt dissociation, significantly improving lithium ion transference number and ionic conductivity compared to existing gel electrolytes. At the same time, the three-dimensional cross-linked network not only solves the phase separation problem of each component, but also forms a stable and compatible interface with the electrode. With its mechanical strength, it inhibits lithium dendrite growth, enabling the electrolyte to maintain excellent long-term cycle stability under high-load battery systems. It provides a reliable electrolyte solution for the industrialization of high-safety, high-energy-density lithium metal batteries, and comprehensively overcomes the core technical pain points of traditional gel electrolytes, such as low ion conduction efficiency, unstable interface, and short cycle life. Attached Figure Description

[0018] Figure 1 The lithium-ion transference number test curve of the calixarene-based composite gel electrolyte prepared according to Example 1 of the present invention is shown.

[0019] Figure 2The Arrhenius curves of the calixarene-based composite gel electrolyte prepared according to Example 1 of the present invention are shown.

[0020] Figure 3 The diagram shows a cycle diagram of a high-load lithium iron phosphate (LFP) electrolyte prepared using Example 1 of the present invention, based on a calixarene-filled composite gel electrolyte assembly. Detailed Implementation

[0021] The technical solution of the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not intended to limit the present invention. The raw materials and reagents used in this embodiment are all conventional commercially available products, and unless otherwise specified, they can be used directly without additional purification; the equipment used are all conventional laboratory equipment, and the operating procedures are all conventional operations, and unless otherwise specified, no special condition control is required.

[0022] The method according to the present invention first comprises reacting polyethylene glycol with isocyanate methacrylate in the presence of a catalyst to undergo a carbamate addition reaction to obtain polyethylene glycol-isocyanate methacrylate. In a preferred embodiment, the molar ratio of polyethylene glycol to isocyanate methacrylate is 1:2.1 to 2.4. In a preferred embodiment, the relative molecular mass of polyethylene glycol is 1000-50000. In a preferred embodiment, the catalyst is at least one selected from dibutyltin dilaurate (DBTDL), stannous octoate, and polyurethane organotin catalyst T9. In a preferred embodiment, the amount of catalyst used is 3-12 mol%, for example 6-10 mol%, based on the molar amount of polyethylene glycol. In a preferred embodiment, the addition reaction is carried out at 60-80°C. In a preferred embodiment, the addition reaction time is 4-6 h. In a preferred embodiment, the addition reaction is carried out in an organic solvent. In a preferred embodiment, the organic solvent is chloroform. In a preferred embodiment, the organic solvent is ultra-dry grade chloroform with a moisture content ≤5 ppm. In a preferred embodiment, the addition reaction is carried out under a first protective atmosphere (e.g., argon atmosphere) where the O2 content is less than 0.01 ppm and the H2O content is less than 0.01 ppm.

[0023] The method according to the present invention further includes mixing polyethylene glycol-isocyanoethyl methacrylate, acrylate, calixarene, and an electrolyte; adding an initiator to initiate a free radical polymerization crosslinking reaction between polyethylene glycol-isocyanoethyl methacrylate and the acrylate, forming a three-dimensional crosslinked network encapsulating the electrolyte and calixarene, thereby obtaining a calixarene-based filler composite gel electrolyte. In a preferred embodiment, the acrylate is one of polyethylene glycol diacrylate (PEGDA), ethylene glycol dimethacrylate, polyethylene glycol methacrylate, ethoxylated trimethylolpropane triacrylate (ETPTA), and ethoxylated pentaerythritol tetraacrylate. In a preferred embodiment, the calixarene is one of calix-4 aromatics, calix-6 aromatics, calix-8 aromatics, tert-butylcalix-4 aromatics, tert-butylcalix-5 aromatics, tert-butylcalix-6 aromatics, tert-butylcalix-8 aromatics, 4-sulfonic acid calixarene, 4-tert-butylthiacalix-4 aromatics, 4-tert-butylthiacalix-6 aromatics, and 4-tert-butylthiacalix-8 aromatics. In a preferred embodiment, the initiator is azobisisobutyronitrile (AIBN). In a preferred embodiment, the electrolyte is a conventional commercial lithium metal battery electrolyte, comprising lithium salt and solvent. In a preferred embodiment, the solvent is one of propylene carbonate, diethyl carbonate, dimethyl carbonate, ethylene carbonate, fluoroethylene carbonate, dioxolane, and dimethyl ether. In a preferred embodiment, the free radical polymerization crosslinking reaction is carried out at 50-70°C. In a preferred embodiment, the free radical polymerization crosslinking reaction time is 1-6 hours. In a preferred embodiment, the solid content in the free radical polymerization crosslinking reaction system is 8-20%, where the solid content = total mass of solid components (i.e., the total mass of polyethylene glycol-isocyanoethyl methacrylate, acrylate, and calixarene) / total mass of the system × 100%). In a preferred embodiment, the solid content is 10-15%. In a preferred embodiment, the free radical polymerization crosslinking reaction is carried out under a second protective atmosphere (e.g., argon atmosphere), where the O2 content is less than 0.01 ppm and the H2O content is less than 0.01 ppm.

[0024] In the calixarene-based composite gel electrolyte obtained by the above method according to the present invention, calixarene is uniformly dispersed in the pores of a three-dimensional cross-linked network, including a large number of urethane bonds (-NH-CO-O-) and methacrylate cross-linked structures. The lithium-ion transference number obtained by DC polarization method is ≥0.7 (e.g., between 0.7 and 0.8), and the ionic conductivity obtained by AC impedance method is ≥0.8 mS / cm (e.g., between 0.8 and 1.0). The high-load lithium iron phosphate (LFP) lithium metal full cell assembled using this composite gel electrolyte retains ≥80% of its capacity after 700 cycles at 2C rate.

[0025] Example 1: Preparation of a composite gel electrolyte system of calix 6 aromatic hydrocarbons + ETPTA

[0026] The operation was carried out in a glove box, with the O2 content controlled to be <0.01ppm and the H2O content <0.01ppm. Polyethylene glycol and isocyanate methacrylate were added to the reaction vessel at a molar ratio of 1:2.1, followed by the addition of ultra-dry chloroform as a solvent. The mixture was stirred until the polyethylene glycol and isocyanate methacrylate were completely dissolved. The catalyst DBTDL was added to the mixture at a concentration of 10 mol% of the polyethylene glycol mass, and stirring continued until the catalyst was completely dispersed. The reaction vessel was placed on a heating device, the temperature was set to 80°C, and magnetic stirring was activated. This temperature and stirring were maintained for 5 hours. After the reaction, the product was transferred to a rotary evaporator to remove the chloroform solvent. The product, after solvent removal, was dried in a dry environment to obtain a white, waxy solid, polyethylene glycol-isocyanate methacrylate, which was then sealed and stored for later use.

[0027] The operation was carried out under an argon protective atmosphere, with the O2 content controlled to be <0.01ppm and the H2O content <0.01ppm. 0.12g of the synthesized polyethylene glycol-isocyanate, 0.12g of ETPTA, 0.04g of calix-6 aromatics, and 0.003g of initiator AIBN were added sequentially to a clean mixing container, followed by commercial electrolyte. The mixture was stirred until all solids were completely dissolved and the system was homogeneous, at which point the solid content was approximately 10% (the solid content was calculated as the ratio of the total mass of polyethylene glycol-isocyanate, ETPTA, and calix-6 aromatics to the total mass of the system). The homogenized mixture was placed in a curing device at 60°C and cured for 4 hours. After curing, the mixture was allowed to cool naturally to room temperature to obtain the target product.

[0028] Figure 1 The figure shows the lithium-ion transference number test curves of the composite gel electrolyte prepared in this embodiment. The figure includes two curves: "Initial" and "Steady". The calculation shows that the lithium-ion transference number of the composite gel electrolyte prepared in this embodiment is as high as 0.76. This indicates that the composite gel electrolyte of the present invention can effectively promote the selective transport of lithium ions, reduce the interference of anions on ion conduction, significantly improve the migration efficiency of lithium ions in the electrolyte, reduce the polarization phenomenon during battery charging and discharging, and provide support for the high-rate performance of the battery.

[0029] Figure 2The Arrhenius curve of the composite gel electrolyte prepared in this embodiment was obtained by linear fitting calculation, and the ion conduction activation energy of the composite gel electrolyte was calculated to be 4.44 kJ / mol. Under room temperature conditions, the ionic conductivity of the composite gel electrolyte reached 0.89 mS / cm, which is much higher than the ionic conductivity of existing conventional gel electrolytes (usually <0.5 mS / cm), proving that the composite gel electrolyte of the present invention has excellent ion conduction ability and can meet the requirement of high electrolyte conductivity for lithium metal batteries.

[0030] Figure 3 The composite gel electrolyte prepared in this embodiment contains highly loaded lithium iron phosphate (LFP) with a loading of 10.5 mg·cm³. -2 The image shows the cycle performance curves of a full battery assembled with lithium metal as the negative electrode and a positive electrode (C) as the positive electrode, at a 2C rate. The upper light gray curve represents the coulombic efficiency, which remains almost 100%, indicating that the charge and discharge are almost identical at a 2C rate, with minimal side reactions and excellent electrochemical reversibility. The lower black curve represents the specific capacity retention rate. After 700 cycles at a 2C rate, the full battery retains 80.6% of its capacity, and the capacity decay trend is gradual during cycling. This demonstrates that the composite gel electrolyte of this invention not only possesses high ionic conductivity and high lithium-ion transference number but also constructs a stable electrolyte-electrode interface, effectively suppressing lithium dendrite growth and significantly improving the long-term cycle stability of lithium metal batteries. It is particularly suitable for lithium metal battery systems with high-load positive electrodes and has potential for industrial application.

[0031] Example 2: Preparation of a composite gel electrolyte system of calix 6 aromatics + ETPTA

[0032] The synthesis steps of polyethylene glycol-isocyanate in this embodiment are exactly the same as those in Example 1, yielding white waxy solid polyethylene glycol-isocyanate, which is then sealed and stored for later use.

[0033] The operation was carried out under an argon protective atmosphere, with the O2 content controlled to be <0.01ppm and the H2O content <0.01ppm. 0.08g of the synthesized polyethylene glycol-isocyanate (PEG-isocyanate content reduced compared to Example 1), 0.12g of ETPTA, 0.04g of calix-6 aromatics, and 0.003g of initiator AIBN were added sequentially to a clean mixing container, followed by commercial electrolyte. The mixture was stirred until all solids were completely dissolved and the system was homogeneous, at which point the solid content was approximately 10% (the amount of commercial electrolyte was reduced compared to Example 1 to ensure the solid content remained approximately 10%). The homogeneous mixture was placed in a curing device at 60°C and cured for 4 hours. After curing, the mixture was allowed to cool naturally to room temperature to obtain the target product.

[0034] Example 3: Preparation of a composite gel electrolyte based on a calix-6 aromatic hydrocarbon + PEGDA system

[0035] The synthesis steps of polyethylene glycol-isocyanate in this embodiment are exactly the same as those in Example 1, yielding white waxy solid polyethylene glycol-isocyanate, which is then sealed and stored for later use.

[0036] The operation was carried out under an argon protective atmosphere, with the O2 content controlled to be <0.01ppm and the H2O content <0.01ppm. 0.12g of the synthesized polyethylene glycol-isocyanoethyl methacrylate, 0.12g of PEGDA (replacing ETPTA in Example 1), 0.04g of calix-6 aromatic hydrocarbon, and 0.003g of initiator AIBN were added sequentially to a clean mixing container, followed by commercial electrolyte. The mixture was stirred until all solids were completely dissolved and the system was homogeneous, at which point the solid content was approximately 10%. The homogeneous mixture was placed in a curing device at 60°C and cured at this temperature for 4 hours. After curing, the mixture was allowed to cool naturally to room temperature to obtain the target product.

[0037] Example 4: Preparation of a composite gel electrolyte based on tert-butylcalix 8-aromatic hydrocarbon + PEGDA system

[0038] The synthesis steps of polyethylene glycol-isocyanate in this embodiment are exactly the same as those in Example 1, yielding white waxy solid polyethylene glycol-isocyanate, which is then sealed and stored for later use.

[0039] The operation was carried out under an argon protective atmosphere, with the O2 content controlled to be <0.01ppm and the H2O content <0.01ppm. 0.12g of the synthesized polyethylene glycol-isocyanate, 0.12g of PEGDA, 0.04g of tert-butylcalix-8 aromatic hydrocarbon (replacing calix-6 aromatic hydrocarbon in Example 3), and 0.003g of initiator AIBN were added sequentially to a clean mixing container, followed by commercial electrolyte. The mixture was stirred until all solid materials were completely dissolved and the system was homogeneous, at which point the solid content was approximately 10%. The homogeneous mixture was placed in a curing device at 60°C and cured at this temperature for 4 hours. After curing, the mixture was allowed to cool naturally to room temperature to obtain the target product.

[0040] Example 5: Preparation of a composite gel electrolyte based on tert-butylcalix 8-aromatic hydrocarbon + PEGDA system

[0041] The synthesis steps of polyethylene glycol-isocyanate in this embodiment are exactly the same as those in Example 1, yielding white waxy solid polyethylene glycol-isocyanate, which is then sealed and stored for later use.

[0042] The operation was carried out under an argon protective atmosphere, with the O2 content controlled to be <0.01ppm and the H2O content <0.01ppm. 0.12g of the synthesized polyethylene glycol-isocyanate, 0.12g of PEGDA, 0.04g of tert-butylcalix-8 aromatic hydrocarbon, and 0.003g of initiator AIBN were added sequentially to a clean mixing container, followed by commercial electrolyte. The mixture was stirred until all solids were completely dissolved and the system was homogeneous, at which point the solid content was approximately 15% (the amount of commercial electrolyte used was reduced compared to Example 4 to increase the relative solid content). The homogenized mixture was placed in a curing device at 60°C and cured for 2 hours (the curing time was shortened compared to Example 4). After curing, the mixture was allowed to cool naturally to room temperature to obtain the target product.

[0043] Example 6: Preparation of a composite gel electrolyte based on a 4-tert-butylthiacalix 8-aromatic hydrocarbon + ETPTA system

[0044] The synthesis steps of polyethylene glycol-isocyanate in this embodiment are exactly the same as those in Example 1, yielding white waxy solid polyethylene glycol-isocyanate, which is then sealed and stored for later use.

[0045] The operation was carried out under an argon protective atmosphere, with the O2 content controlled to be <0.01ppm and the H2O content <0.01ppm. 0.12g of the synthesized polyethylene glycol-isocyanate, 0.12g of ETPTA (replacing PEGDA in Example 5), 0.04g of 4-tert-butylthiacalix-8 aromatic hydrocarbon (replacing tert-butylcalix-8 aromatic hydrocarbon in Example 5), and 0.003g of initiator AIBN were added sequentially to a clean mixing container, followed by commercial electrolyte. The mixture was stirred until all solid materials were completely dissolved and the system was homogeneous, at which point the solid content was approximately 15%. The homogeneous mixture was placed in a curing device at 60°C and cured at this temperature for 2 hours. After curing, the mixture was allowed to cool naturally to room temperature to obtain the target product.

[0046] Traditional polyethylene glycol (PEG)-based gel electrolytes suffer from two major drawbacks: first, PEG molecular chains tend to form regular crystalline regions, and the dense crystalline structure hinders lithium-ion migration; second, lithium salts (such as LiTFSI and LiPF6) readily form stable Li+ ions within the PEG matrix. + -TFSI - Ion pairs, electrostatic interactions bind Li +The free movement of lithium leads to low ion conduction efficiency. This invention, through the modification of polyethylene glycol-isocyanoethyl methacrylate and the introduction of calixarene, first utilizes intermolecular hydrogen bonds to overcome this limitation. Specifically, the urethane bonds (-NHCOO-) on the polyethylene glycol-isocyanoethyl methacrylate molecular chain, containing hydrogen bond donors (NH bonds), can form multiple hydrogen bond interactions with the phenolic hydroxyl groups (-OH, hydrogen bond acceptors) on the calixarene molecule. This hydrogen bonding significantly disrupts the regular arrangement of the polyethylene glycol molecular chain, destroys its crystalline structure, and causes the polyethylene glycol matrix to form loose amorphous regions. Simultaneously, the loose matrix environment provides ample space for lithium salt dissociation, effectively weakening the lithium dissociation. + -TFSI - The electrostatic interaction between ion pairs promotes ion pair separation, generating more freely mobile Li. + This lays the foundation for lithium-ion conduction.

[0047] Building upon this, the functional structure of calixarene further enables selective lithium-ion transport. Calcineurenes possess cage-like cavities of controllable size (diameter < 7.9 Å), the size of which is precisely smaller than the TFSI anion in the battery system. - The dynamic diameter (7.9 Å), based on the size displacement effect, TFSI - Lithium ions (Li⁺ with a kinetic diameter of only 0.76 Å) cannot pass through the calixarene cavity, while lithium ions can pass through the cavity smoothly; this screening effect can directly reduce TFSI. - Interference with Li⁺ migration can further weaken the interaction between Li⁺ and TFSI. - The electrostatic bonding significantly increases the proportion of free Li⁺, ultimately achieving a high lithium-ion transference number (such as 0.76 in Example 1).

[0048] Furthermore, the chemical crosslinking design of polyethylene glycol-isocyanate (PEG) and acrylate provides a stable macroscopic structural support. The methacrylate double bonds branched into the PEG-PEG molecule can undergo free radical polymerization crosslinking with the acrylate double bonds of multifunctional acrylates (such as ETPTA and PEGDA) under the action of an initiator, forming an interconnected three-dimensional ion-conducting network in situ. This three-dimensional network, on the one hand, firmly binds the PEG-PEG matrix, calixarene filler, and electrolyte within the network structure, effectively avoiding phase separation problems among the components; on the other hand, the three-dimensional network can form a tight and stable interfacial contact with the electrode surface (lithium metal anode, lithium iron phosphate cathode), reducing interfacial impedance. Simultaneously, its mechanical strength can inhibit the growth and puncture of lithium dendrites in the lithium metal anode during cycling, maintaining the overall stability of the lithium-ion battery during cycling.

[0049] In summary, through the synergistic effect of hydrogen bond breaking crystallization to promote dissociation, calixarene screening to improve ion efficiency, and three-dimensional network stabilization to ensure cycle stability, the composite gel electrolyte of this invention can simultaneously achieve high ionic conductivity (up to 0.89 mS / cm at room temperature), high lithium-ion transference number, and excellent cycle stability (such as the high-load LFP battery in Example 1, which maintained a capacity retention of 80.6% after 700 cycles at 2C rate). This effectively solves the core technical pain points of traditional gel electrolytes and meets the practical application requirements of high-safety and high-energy-density lithium-ion batteries.

[0050] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the invention. Various variations can be made to the above embodiments of the present invention. That is, all simple and equivalent changes and modifications made based on the claims and description of this invention fall within the protection scope of the claims. All aspects not described in detail in this invention are conventional technical content.

Claims

1. An in-situ preparation method of a calixarene filler composite gel electrolyte, characterized in that, The in-situ preparation method comprises the following steps: S1, polyethylene glycol and isocyanatoethyl methacrylate are subjected to urethane addition reaction under the action of a catalyst to obtain polyethylene glycol-isocyanatoethyl methacrylate; S2, polyethylene glycol-isocyanatoethyl methacrylate, an acrylate, a calixarene and an electrolyte are mixed, and an initiator is added to initiate free radical polymerization crosslinking reaction between polyethylene glycol-isocyanatoethyl methacrylate and the acrylate, so as to form a three-dimensional crosslinked network wrapping the electrolyte and the calixarene, thereby obtaining a calixarene filler composite gel electrolyte.

2. The in-situ preparation method according to claim 1, characterized in that, In step S1, the molar ratio of polyethylene glycol and isocyanatoethyl methacrylate is 1:2.1-2.

4.

3. The in-situ preparation method according to claim 1, characterized in that, In step S1, the catalyst is at least one of DBTDL, stannous octoate, and polyurethane organotin catalyst T9.

4. The in-situ preparation method according to claim 1, characterized in that, In step S1, the amount of catalyst is 3-10 mol% based on the amount of substance of polyethylene glycol.

5. The in-situ method of claim 1, wherein, In step S1, the addition reaction is carried out at 60-80℃.

6. The in-situ method of claim 1, wherein, In step S2, the acrylate is one of polyethylene glycol diacrylate, ethylene glycol dimethacrylate, polyethylene glycol methacrylate, ethoxylated trimethylolpropane triacrylate, and ethoxylated pentaerythritol tetraacrylate.

7. The in-situ method of claim 1, wherein, In step S2, the calixarene is one of calix4arene, calix6arene, calix8arene, t-butyl calix4arene, t-butyl calix5arene, t-butyl calix6arene, t-butyl calix8arene, 4-sulfonic acid calixarene, 4-t-butylthiacalix4arene, 4-t-butylthiacalix6arene, and 4-t-butylthiacalix8arene.

8. The in-situ method of claim 1, wherein, In step S2, the solvent in the electrolyte is one of propylene carbonate, diethyl carbonate, dimethyl carbonate, ethylene carbonate, fluoroethylene carbonate, dioxolane, and dimethyl ether.

9. The in-situ method of claim 1, wherein, In step S2, the solid content in the free radical polymerization crosslinking reaction system is 8-20%.

10. The calixarene filler composite gel electrolyte obtained by the in-situ preparation method according to any one of claims 1-9.

Images