CN-122025785-A - Preparation method of composite gel polymer electrolyte with reinforced concrete multi-scale structure

CN122025785ACN 122025785 ACN122025785 ACN 122025785ACN-122025785-A

Abstract

The invention discloses a preparation method of a composite gel polymer electrolyte with a reinforced concrete multi-scale structure, which adopts a double-nozzle electrostatic spinning technology to respectively prepare a polymer with high mechanical strength and high thermal stability and a polymer with high ionic conductivity and low glass transition temperature into coarse and fine fiber spinning solutions, and synchronously spin under the set temperature and humidity conditions to obtain a multi-scale composite fiber membrane with coarse and fine fiber interweaving. The reinforced concrete network is structurally introduced with micro-nano heterogeneous porous channels and multiple fiber crosslinking points, so that the wettability, mechanical elasticity and interface compatibility of the electrolyte are greatly improved. The electrolyte has high mechanical strength, high thermal stability and excellent ion conduction capacity, and effectively improves the safety performance and the cycle life of the battery. The flame retardant and dendrite growth inhibition agent is applied to lithium metal batteries, so that the flame retardant and dendrite growth inhibition agent can be obviously enhanced, and the development requirements of high-safety and high-energy-density lithium batteries can be met.

Inventors

ZUO PENGJIAN
YANG HAIXIA
XU SHILIN
CHENG GUANGYU
YAN JIAXIN
WANG YUANHENG
LI YIFAN
CHEN XIN

Assignees

哈尔滨工业大学

Dates

Publication Date: 20260512
Application Date: 20260309

Claims (10)

1. A method for preparing a composite gel polymer electrolyte with a 'reinforced concrete' multi-scale structure, which is characterized by comprising the following steps: step one, selecting a polymer with high mechanical strength and high thermal stability, dissolving the polymer in a low-volatility organic solvent, and stirring the solvent to obtain uniform and high-viscosity crude fiber spinning solution; step two, selecting a polymer with high ionic conductivity and low glass transition temperature to dissolve in a high-volatility organic solvent and stirring to obtain a uniform and moderate-viscosity fine fiber spinning solution; Step three, respectively injecting the crude fiber spinning solution and the fine fiber spinning solution into two injectors; Preparing a multi-scale fiber membrane with coarse and fine fiber interweaving through a double-nozzle electrostatic spinning technology; fifthly, after the electrostatic spinning is finished, performing heat treatment on the obtained multi-scale fiber film to remove residual solvent; And step six, in an inert atmosphere glove box, dropwise adding a liquid electrolyte into the composite membrane, and obtaining the composite gel polymer electrolyte with the reinforced concrete multi-scale structure after the liquid electrolyte swells.
2. The method for preparing the composite gel polymer electrolyte with the multi-scale structure of reinforced concrete according to claim 1, wherein in the first step, the polymer with high mechanical strength and high thermal stability is one or more of polytetrafluoroethylene-hexafluoropropylene, aramid, polyimide, polyetherimide, poly-p-phenylene benzobisoxazole, polyamide and polyether ether ketone, and the low-volatility organic solvent is one or more of N, N-dimethylformamide, N-methylpyrrolidone, dimethyl sulfoxide and N, N-dimethylacetamide.
3. The method for preparing the composite gel polymer electrolyte with the 'reinforced concrete' multi-scale structure according to claim 1, wherein in the first step, the concentration of the polymer in the crude fiber spinning solution is 0.05-1.2 g/mL, the temperature is 25-80 ℃, and the stirring time is 10-15 h.
4. The method for preparing the composite gel polymer electrolyte with the multi-scale structure of reinforced concrete according to claim 1, wherein in the second step, the polymer with high ion conductivity and low glass transition temperature is one or more of polyethylene oxide, polyacrylonitrile, polymethyl methacrylate, polyvinyl alcohol, polyvinylpyrrolidone, polyvinyl butyl ether, polyvinyl carboxylate and polypropylene carbonate, and the high-volatility organic solvent is one or more of dichloromethane, tetrahydrofuran, acetone, ethanol and ethyl acetate.
5. The method for preparing the composite gel polymer electrolyte with the 'reinforced concrete' multi-scale structure according to claim 1, wherein in the second step, the concentration of the polymer in the fine fiber spinning solution is 0.02-0.7 g/mL, the temperature is 25-80 ℃, and the stirring time is 10-15 h.
6. The method for preparing a composite gel polymer electrolyte with a multi-scale structure of 'reinforced concrete' according to claim 1, wherein in the fourth step, the spinning process is performed in a constant temperature and humidity chamber, the temperature in the chamber is set to 40 ℃, and the relative humidity is maintained to 40%.
7. The preparation method of the composite gel polymer electrolyte with the reinforced concrete multi-scale structure is characterized in that in the fourth step, the spray head propulsion rate of the fine fiber spinning solution is 0.1-1.2 mL/h, the working voltage applied by the spray head is 14-25 kV, the distance from the tip of the spray head needle to the surface of the rotary receiving cylinder is 10-30 cm, the spray head propulsion rate of the coarse fiber spinning solution is 0.3-1.8 mL/h, the working voltage applied by the spray head is 8-20 kV, and the distance from the tip of the spray head needle to the surface of the rotary receiving cylinder is 14-25 cm.
8. The method for preparing the composite gel polymer electrolyte with the 'reinforced concrete' multi-scale structure according to claim 1, wherein in the fifth step, the heat treatment temperature is 50-120 ℃ and the time is 1-12 h.
9. The method for preparing a composite gel polymer electrolyte with a reinforced concrete multi-scale structure according to claim 1, wherein in the fifth step, the diameter of coarse fibers in the multi-scale fiber membrane is 0.5-5 μm, the diameter of fine fibers is 0.01-0.5 μm, and the thickness of the membrane after the multi-scale fiber membrane is dried is 10-100 μm.
10. The method for preparing a composite gel polymer electrolyte with a multi-scale structure of steel bar-concrete according to claim 1, wherein in the step six, the liquid electrolyte comprises one of a liquid ether electrolyte and a liquid ester electrolyte.

Description

Preparation method of composite gel polymer electrolyte with reinforced concrete multi-scale structure Technical Field The invention belongs to the technical field of polymer electrolytes of lithium batteries, relates to a preparation method of a polymer electrolyte, and in particular relates to a preparation method of a composite gel polymer electrolyte with a reinforced bar-concrete multi-scale structure. Background With the rapid development of new energy automobiles and energy storage industry, higher requirements are put on the energy density and the safety of lithium batteries. The traditional liquid electrolyte has the risks of inflammability and easy leakage, and is easy to cause thermal runaway when overcharged and overheated, and the traditional liquid electrolyte becomes a bottleneck of the battery towards high specific energy. Therefore, quasi-solid polymer electrolytes that can fundamentally eliminate leakage and combustion hazards are considered as key materials for next-generation high-safety lithium batteries. However, practical applications of quasi-solid electrolytes face fundamental contradictions that "mechanical strength-ionic conductivity" is difficult to coordinate. While polymers with high modulus and excellent thermal stability (such as aramid, polyimide, etc.) generally have extremely low ionic conductivity, polymers with high ionic conductivity potential (such as polyethylene oxide PEO) have weak mechanical strength, cannot effectively inhibit lithium dendrite penetration, and have high risk of battery short circuit. This opposition makes it difficult for a single component system to compromise safety and performance requirements. In addition, in the preparation process, although the electrostatic spinning technology can construct a porous fiber membrane, the membrane prepared by the traditional method still has obvious limitations that the fiber diameter and the pore diameter are single in distribution, the infiltration and ion transmission efficiency are affected, the fibers are stacked in a 'point contact' mode, so that the interface resistance is high, the mechanical stability is poor, most polymers are thermally shrunk at high temperature, the membrane pores are easily closed or shrunk in size, and the short circuit in the battery is induced, so that serious potential safety hazards are brought. Therefore, how to break the performance of the existing material system through innovative structural design, and to construct a composite polymer electrolyte with high mechanical strength, high ionic conductivity, excellent thermal stability and good interface compatibility has become a key subject for promoting the development of high-safety and high-energy-density solid/quasi-solid batteries. Disclosure of Invention The invention provides a preparation method of a composite gel polymer electrolyte with a reinforced concrete multi-scale structure, which aims to overcome the technical defect that the existing gel polymer electrolyte is difficult to simultaneously realize high ionic conductivity, high mechanical strength, excellent thermal stability and good interface compatibility. The invention imitates the synergistic action principle of steel bars and concrete in constructional engineering, and aims to construct a multi-scale and multi-component composite fiber network through electrostatic spinning to realize the synergistic improvement and complementary advantages of various performances of electrolyte, wherein polymer membrane coarse fibers adopt high-strength and high-thermal-stability polymers to form a rigid framework, extremely high modulus and puncture resistance strength are provided, lithium dendrites are physically blocked, the dimensional integrity of a battery at high temperature is ensured, the diaphragm is prevented from shrinking, flexible matrixes are formed by polymer with high ion conductivity to form continuous ion conducting phases, and soft fine fibers can better wrap the coarse fibers and attach to the surface of an electrode, so that excellent interface contact is ensured. The invention aims at realizing the following technical scheme: A preparation method of a composite gel polymer electrolyte with a 'reinforced concrete' multi-scale structure comprises the following steps: step one, selecting a polymer with high mechanical strength and high thermal stability, dissolving the polymer in a low-volatility organic solvent, and stirring the solvent to obtain uniform and high-viscosity crude fiber spinning solution; step two, selecting a polymer with high ionic conductivity and low glass transition temperature to dissolve in a high-volatility organic solvent and stirring to obtain a uniform and moderate-viscosity fine fiber spinning solution; Step three, respectively injecting the crude fiber spinning solution and the fine fiber spinning solution into two injectors; Preparing a multi-scale fiber membrane with coarse and fine fiber interweaving through a double-n