阅读说明：本技术 石墨烯筛接枝超支化聚氨酯自修复粘结剂及其制备与应用 (Graphene sieve grafted hyperbranched polyurethane self-repairing binder and preparation and application thereof ) 是由 杨应奎 和启明 何承恩 张金龙 王相刚 于 2020-10-22 设计创作，主要内容包括：本发明提供了一种石墨烯筛接枝超支化聚氨酯自修复粘结剂及其制备与应用,能够提高电池的安全性和循环使用寿命,在加热、光照等刺激下加速自修复过程,并改善自修复效果。该自修复粘结剂的制备方法为：首先制备石墨烯筛GM,进而以氨基偶氮苯衍生物为功能化试剂,采用溶剂热法修饰GM,得到氨基功能化石墨烯筛NGM；然后共价接枝超支化聚氨酯HPU和自愈合功能基团SHG,得到石墨烯筛接枝超支化聚氨酯自修复复合材料NGM-HPU-SHG。NGM-HPU-SHG可用于超级电容器或锂/钠离子电池中,代替聚偏氟乙烯或聚四氟乙烯等传统粘结剂,获得更优异的电性能和自修复效果。(The invention provides a graphene sieve grafted hyperbranched polyurethane self-repairing binder, and preparation and application thereof, which can improve the safety and cycle service life of a battery, accelerate the self-repairing process under the stimulation of heating, illumination and the like, and improve the self-repairing effect. The preparation method of the self-repairing binder comprises the following steps: firstly, preparing a graphene sieve GM, and then modifying the GM by using an aminoazobenzene derivative as a functionalized reagent and adopting a solvothermal method to obtain an amino functionalized graphene sieve NGM; and then covalently grafting hyperbranched polyurethane HPU and a self-healing functional group SHG to obtain the graphene sieve grafted hyperbranched polyurethane self-healing composite material NGM-HPU-SHG. The NGM-HPU-SHG can be used in a super capacitor or a lithium/sodium ion battery to replace the traditional binders such as polyvinylidene fluoride or polytetrafluoroethylene and the like, and has more excellent electrical property and self-repairing effect.)

1. The preparation method of the graphene sieve grafted hyperbranched polyurethane self-repairing binder is characterized by comprising the following steps of:

firstly, preparing a graphene sieve GM, and then modifying the GM by using an aminoazobenzene derivative as a functionalized reagent and adopting a solvothermal method to obtain an amino functionalized graphene sieve NGM; and then covalently grafting hyperbranched polyurethane HPU and a self-healing functional group SHG to obtain the graphene sieve grafted hyperbranched polyurethane self-healing binder NGM-HPU-SHG.

2. The preparation method of the graphene sieve grafted hyperbranched polyurethane self-repairing binder according to claim 1, which is characterized by comprising the following steps:

the preparation method of the graphene sieve GM comprises the following steps: ultrasonically dispersing graphite oxide or graphene oxide into an aqueous solution to obtain a dispersion liquid with the concentration of 1-2 mg/mL, adding 0.1-10 mg/mL of a transition metal salt solution into the dispersion liquid, wherein the mass ratio of the transition metal salt to the graphene oxide is 0.2: 1-5: 1, carrying out ultrasonic reaction for 15-60 min at 50-80 ℃, carrying out hydrothermal reaction for 4-12 hours at 100-180 ℃, washing with deionized water, freeze-drying to obtain powder, carrying out heat treatment on the powder at 300-800 ℃ for 0.5-6 hours under the protection of inert gas, and finally soaking with dilute hydrochloric acid, washing, and freeze-drying to obtain the graphene oxide/graphene oxide composite material.

3. The preparation method of the graphene sieve grafted hyperbranched polyurethane self-repairing binder according to claim 2, which is characterized by comprising the following steps:

the concentration of the transition metal salt solution is 0.1-10 mg/mL, the transition metal is any one of ferric chloride, nickel sulfate and cobalt nitrate, and the mass ratio of the transition metal salt to the graphene oxide is 0.2: 1-5: 1.

4. The preparation method of the graphene sieve grafted hyperbranched polyurethane self-repairing binder according to claim 1, which is characterized by comprising the following steps:

the preparation method of the graphene sieve GM comprises the following steps: ultrasonically dispersing graphite oxide or graphene oxide into an aqueous solution to obtain a dispersion liquid with the concentration of 1-2 mg/mL, adding a proper amount of hydrogen peroxide or potassium permanganate into the dispersion liquid, reacting for 0.5-6 hours at 30-80 ℃, centrifuging, washing with deionized water, dispersing in water, performing hydrothermal reaction for 4-12 hours at 100-180 ℃, and freeze-drying to obtain the graphene oxide/graphene composite material.

5. The preparation method of the graphene sieve grafted hyperbranched polyurethane self-repairing binder according to claim 4, which is characterized by comprising the following steps:

wherein, the ratio of graphite oxide or graphene oxide: the mass ratio of hydrogen peroxide or potassium permanganate is 0.1: 1-1: 1.

6. The preparation method of the graphene sieve grafted hyperbranched polyurethane self-repairing binder according to claim 1, which is characterized by comprising the following steps:

ultrasonically dispersing a graphene sieve GM into N, N-dimethylformamide DMF or N-methylpyrrolidone NMP to prepare graphene sieve GM dispersion liquid with the concentration of 1-2 mg/mL, dropwise adding an aminoazobenzene derivative, reacting at 120-180 ℃ for 6-24 hours to obtain an aminated graphene sieve NGM, cooling to 0-50 ℃, dropwise adding an appropriate amount of diisocyanate, continuing to react for 2-12 hours to react with amino on the surface of the NGM, so that covalent grafting is carried out on the surface of the NGM, then adding triol/amine and a self-repairing functional monomer, reacting for 6-12 hours, heating to 50-120 ℃ and continuing to react for 6-24 hours, and carrying out suction filtration, washing and vacuum drying to obtain a graphene sieve-grafted hyperbranched polyurethane self-repairing binder NGM-HPU-SHG;

the reaction equation is as follows:

7. the preparation method of the graphene sieve grafted hyperbranched polyurethane self-repairing binder according to claim 6, which is characterized by comprising the following steps:

wherein the diisocyanate comprises one or more of 1, 6-hexamethylene diisocyanate HDI, diphenylmethane diisocyanate MDI, toluene diisocyanate TDI, 4' -dicyclohexylmethane diisocyanate HMDI, 1, 5-naphthalene diisocyanate, trimethyl-1, 6-hexamethylene diisocyanate TMHDI and isophorone diisocyanate IPDI;

the aminoazobenzene derivative comprises one or more of 4,4' -diamino-azobenzene, 3' -diamino-4, 4' -dihydroxy-azobenzene and derivatives thereof, and the structural formula is as follows:

the triol/amine being AB₂A type compound comprising at least one of triethanolamine, diisopropanolamine, glycerol, melamine, diethanolamine DEA and its homologues DDEGA and DTEGA;

8. the preparation method of the graphene sieve grafted hyperbranched polyurethane self-repairing binder according to claim 6, which is characterized by comprising the following steps:

wherein, the self-repairing functional monomer comprises one or more of the following monomer molecules:

9. graphene sieve grafting hyperbranched polyurethane self-repairing binder is characterized in that:

the preparation method of any one of claims 1 to 8.

10. The graphene sieve grafted hyperbranched polyurethane self-healing binder of claim 9 is used in a supercapacitor or lithium/sodium ion battery.

Technical Field

The invention belongs to the technical field of electrochemical cells, and particularly relates to a graphene sieve grafted hyperbranched polyurethane self-repairing binder and preparation and application thereof.

Technical Field

In recent years, with the rapid development of portable flexible electronic technologies such as wearable devices, flexible displays, health monitoring sensors, and the like, research and development of flexible energy storage devices bearing energy supplies, especially electrochemical energy storage devices, are receiving much attention. Currently, flexible electrochemical energy storage devices face mainly two problems: 1) in the process of charging and discharging, along with the embedding and the de-embedding of ions, the electrode material can expand and contract, electrode pulverization and de-bonding are easily caused, the utilization rate is reduced, and further capacity reduction and service life attenuation are caused. 2) The traditional lithium ion battery, super capacitor and the like usually use fragile inorganic materials as electrodes, and the stability of devices is poor in mechanical deformation processes such as bending and folding, so that the electrode materials and current collectors are easily separated, or mechanical damage is generated, the electrochemical performance of the devices is weakened, and even the safety problem caused by electrolyte leakage and the like is solved.

The electrode of the electrochemical energy storage device is composed of an electrode active material, a conductive agent, a binder and a current collector, wherein the binder is one of important auxiliary functional materials in the electrode, has no capacity and small specific gravity in the battery, but is a main source of mechanical properties of the whole electrode, and has important influence on the electrochemical properties of the battery. Polyvinylidene fluoride (PVDF), Polytetrafluoroethylene (PTFE), Styrene Butadiene Rubber (SBR) emulsion, and carboxymethyl cellulose (CMC) are currently common binders. Among them, PVDF has good cohesiveness, excellent mechanical properties, and strong electrochemical corrosion resistance, and has been widely used in lithium ion battery electrodes at present. However, PVDF is a crystalline polymer, and the degree of crystallinity is as high as about 50%, which is difficult to adapt to the huge volume expansion of the electrode material with high specific capacity during charging and discharging, and at the same time, it can seriously hinder the diffusion and circulation of electrolyte ions, and limit the rate capability of the battery. In addition, as charging and discharging are carried out, the PVDF binder undergoes side reactions, destroys C-C and C-H bonds, decreases stability, and consumes active Li, resulting in detachment of an electrode active material from a current collector, capacity fading, and a significant decrease in cycle performance of a battery.

Therefore, it is desired to develop a binder having a self-repairing function, which has good viscoelasticity and high ionic conductivity, and can improve the rate capability, safety and stability of an electrode. The treximin (the influence of the self-repairing polysiloxane on the energy storage characteristic of the lithium sulfur battery, a master academic paper of Harbin university, 2018, Chapter IV) uses the self-repairing polysiloxane (PDMS-DFB) as a binder of the lithium sulfur battery electrode to replace the traditional PVDF, so that the volume change of an electrode active material can be self-adapted, the damage in the charging and discharging process can be self-repaired, the falling of the active material is avoided, and the cycling stability of the electrode is improved. However, the mass ratio of PDMS-DFB in the system is as high as 50%, and the electrode active material is only 25%, which limits the improvement of the whole energy storage capacity of the energy storage device. Li juan reports "research on polyacrylic acid-based lithium ion battery silicon negative electrode binder" (master academic paper of university of south china, 2019), by compounding polyacrylic acid (PAA) with a flexible polymer, the resilience and toughness of the binder are increased to some extent, so that huge volume expansion of silicon particles can be more effectively coped with, and the cycle stability is improved. However, PAA mainly utilizes double hydrogen bonds, has low self-repairing efficiency, poor mechanical properties of the polymer, cracks in the electrode after 500 cycles, and low capacity retention rate.

Disclosure of Invention

The invention is made to solve the above problems, and aims to provide a graphene sieve grafted hyperbranched polyurethane self-repairing binder, and a preparation method and an application thereof, which can improve the safety and the cycle service life of a battery, accelerate the self-repairing process under the stimulation of heating, illumination and the like, and improve the self-repairing effect.

In order to achieve the purpose, the invention adopts the following scheme:

< preparation method >

The invention provides a preparation method of a graphene sieve grafted hyperbranched polyurethane self-repairing binder, which is characterized by comprising the following steps: firstly, preparing a graphene sieve GM, and then modifying the GM by using an aminoazobenzene derivative as a functionalized reagent and adopting a solvothermal method to obtain an amino functionalized graphene sieve NGM; and then covalently grafting hyperbranched polyurethane HPU and self-healing functional groups to obtain the graphene sieve grafted hyperbranched polyurethane self-healing composite material NGM-HPU-SHG.

Preferably, the preparation method of the graphene sieve grafted hyperbranched polyurethane self-repair binder provided by the invention can also have the following characteristics: the preparation method of the graphene sieve GM comprises the following steps: ultrasonically dispersing graphite oxide or graphene oxide into an aqueous solution to obtain a dispersion liquid with the concentration of 1-2 mg/mL, adding 0.1-10 mg/mL of a transition metal salt solution into the dispersion liquid, wherein the mass ratio of the transition metal salt to the graphene oxide is 0.2: 1-5: 1, carrying out ultrasonic reaction for 15-60 min at 50-80 ℃, carrying out hydrothermal reaction for 4-12 hours at 100-180 ℃, washing with deionized water, freeze-drying to obtain powder, carrying out heat treatment on the powder at 300-800 ℃ for 0.5-6 hours under the protection of inert gas, and finally soaking with dilute hydrochloric acid, washing, and freeze-drying to obtain the graphene oxide/graphene oxide composite material.

Preferably, the preparation method of the graphene sieve grafted hyperbranched polyurethane self-repair binder provided by the invention can also have the following characteristics: the concentration of the transition metal salt solution is 0.1-10 mg/mL, the transition metal is any one of ferric chloride, nickel sulfate and cobalt nitrate, and the mass ratio of the transition metal salt to the graphene oxide is 0.2: 1-5: 1.

Preferably, the preparation method of the graphene sieve grafted hyperbranched polyurethane self-repair binder provided by the invention can also have the following characteristics: the preparation method of the graphene sieve GM comprises the following steps: ultrasonically dispersing graphite oxide or graphene oxide into an aqueous solution to obtain a dispersion liquid with the concentration of 1-2 mg/mL, adding a proper amount of hydrogen peroxide or potassium permanganate into the dispersion liquid, reacting for 0.5-6 hours at 30-80 ℃, centrifuging, washing with deionized water, dispersing in water, performing hydrothermal reaction for 4-12 hours at 100-180 ℃, and freeze-drying to obtain the graphene oxide/graphene composite material.

Preferably, the preparation method of the graphene sieve grafted hyperbranched polyurethane self-repair binder provided by the invention can also have the following characteristics: graphite oxide or graphene oxide: the mass ratio of hydrogen peroxide or potassium permanganate is 0.1: 1-1: 1.

Preferably, the preparation method of the graphene sieve grafted hyperbranched polyurethane self-repair binder provided by the invention can also have the following characteristics: ultrasonically dispersing a graphene sieve GM into N, N-dimethylformamide DMF or N-methylpyrrolidone NMP to prepare graphene sieve GM dispersion liquid with the concentration of 1-2 mg/mL, dropwise adding an aminoazobenzene derivative, reacting for 6-24 hours at 120-180 ℃ to obtain an aminated graphene sieve NGM, cooling to 0-50 ℃, dropwise adding an appropriate amount of diisocyanate, continuing to react for 2-12 hours to react with amino on the surface of the NGM, so that the diisocyanate is covalently grafted to the surface of the NGM, then adding trihydric alcohol/amine and a self-repairing functional monomer, reacting for 6-12 hours, heating to 50-120 ℃, continuing to react for 6-24 hours, and performing suction filtration, washing and vacuum drying to obtain a graphene sieve grafted hyperbranched polyurethane self-repairing composite material NGM-HPU-SHG;

the reaction equation is as follows:

preferably, the preparation method of the graphene sieve grafted hyperbranched polyurethane self-repair binder provided by the invention can also have the following characteristics: the diisocyanate comprises one or more of 1, 6-hexamethylene diisocyanate HDI, diphenylmethane diisocyanate MDI, toluene diisocyanate TDI, 4' -dicyclohexylmethane diisocyanate HMDI, 1, 5-naphthalene diisocyanate, trimethyl-1, 6-hexamethylene diisocyanate TMHDI and isophorone diisocyanate IPDI;

the aminoazobenzene derivative comprises one or more of 4,4' -diamino-azobenzene, 3' -diamino-4, 4' -dihydroxy-azobenzene and derivatives thereof, and the structural formula is as follows:

the triol/amine being AB₂A type compound comprising at least one of triethanolamine, diisopropanolamine, glycerol, melamine, diethanolamine DEA and its homologues DDEGA and DTEGA;

preferably, in the preparation method of the graphene sieve grafted hyperbranched polyurethane self-repair binder provided by the invention, the self-repair functional monomer comprises one or more of the following monomer molecules:

among them, the reversible self-healing reaction of a typical di-a reactive group and multiple hydrogen bonding groups is as follows:

< Binder >

Further, the invention also provides a graphene sieve grafted hyperbranched polyurethane self-repairing binder, which is characterized in that: prepared by the method described in < preparation methods > in the text.

< application >

Furthermore, the graphene sieve grafted hyperbranched polyurethane self-repairing binder described by the binder is also used in a super capacitor or a lithium/sodium ion battery. Specifically, the graphene sieve grafted hyperbranched polyurethane self-repairing binder is used as a binder of a super capacitor or a lithium/sodium ion battery to replace traditional binders such as polyvinylidene fluoride or polytetrafluoroethylene, an electrode active material, a conductive agent, a graphene sieve grafted hyperbranched polyurethane self-repairing composite material and N-methyl pyrrolidone are mixed according to a certain mass ratio, wherein the solid content of the graphene sieve grafted hyperbranched polyurethane self-repairing binder in electrode slurry is 2-20%, and the mixture is ground, ball-milled or ultrasonically processed to obtain electrode slurry, so that a super capacitor or lithium/sodium ion battery electrode is prepared.

Action and Effect of the invention

In the graphene sieve grafted hyperbranched polyurethane self-repairing binder provided by the invention, the graphene sieve is of a flaky porous structure and has a large specific surface area, so that the graphene sieve grafted hyperbranched polyurethane self-repairing binder has better surface coating and protecting effects on an electrode active material, can effectively prevent electrode pulverization, and improves the mechanical property and the cycling stability of an energy storage device; the in-plane hole structure of the graphene sieve and the hyperbranched structure of the HPU are beneficial to ion diffusion, the electrochemical reaction of the electrode is promoted, and the rate performance and the charging and discharging speed are improved; the HPU and the self-healing functional groups can generate a synergistic effect, damage inside the electrode can be timely repaired through multiple hydrogen bonds, reversible chemical bonds and the like, meanwhile, the self-healing groups inside the binder material can realize reversible reaction under the environment of heat and light (including visible light and ultraviolet light), therefore, the conditions of light, heat and the like can be used for promoting the flexible energy storage device to realize self-healing, the graphene grafted hyperbranched polyurethane self-healing composite material can be applied to a super capacitor and serves as a binder in a lithium/sodium ion battery, the safety and the cycle service life of flexible wearable equipment can be further improved, the self-healing process is accelerated under the stimulation of heating, illumination and the like, and the self-healing effect is improved.

Drawings

Fig. 1 is a TEM image of graphene sieve GM grafted hyperbranched polyurethane self-healing binder prepared in example;

FIG. 2 is an SEM image of a lithium ion battery electrode prepared in the example and using a GM grafted hyperbranched polyurethane self-repairing binder as a binder after repeated bending-self-repairing;

FIG. 3 is a graph showing the charge-discharge cycle stability of the GM grafted hyperbranched polyurethane self-healing binder prepared in the example;

FIG. 4 is a graph of the cycle stability of a lithium ion battery using a conventional PVDF binder;

fig. 5 is a rate performance curve for a battery using GM-grafted hyperbranched polyurethane self-healing binder in an example.

Detailed Description

The following describes specific embodiments of the graphene sieve-loaded hyperbranched polyurethane self-repair binder and preparation and application thereof in detail with reference to the accompanying drawings.

< example >

The preparation method of the graphene sieve grafted hyperbranched polyurea-urethane self-repair binder provided by the embodiment comprises the following steps:

firstly, weighing 1g of graphite oxide, dispersing the graphite oxide into 500mL of water, carrying out water bath ultrasound for 2 hours to obtain uniform dispersion liquid, adding 2g of ferric chloride, carrying out ultrasound for 60min at 50 ℃, transferring the mixture to a hydrothermal reaction kettle, carrying out hydrothermal reaction for 8 hours at 120 ℃, washing the mixture with deionized water, carrying out freeze drying, carrying out heat treatment on the powder for 4 hours at 500 ℃ under the protection of inert gas, and finally soaking the powder for 12 hours with dilute hydrochloric acid, washing, and carrying out freeze drying to obtain the graphene sieve (GM).

As shown in fig. 1, square holes with the diameter of 20-50 nm are uniformly distributed on the surface of the GM two-dimensional sheet layer, and the holes with uniform structure are beneficial to the diffusion of ions in the electrochemical reaction process, so that the power density of the battery is improved; meanwhile, the edge of the hole contains more reactive sites, so that covalent grafting reaction can be carried out on the hole and aminoazobenzene, the grafting density of the self-healing group is improved, and the self-healing efficiency of the binder is improved; in addition, the regular square holes are also beneficial to improving the utilization rate of the electrode active material, thereby improving the energy density of the electrode.

It should be noted that the size and density of the square holes can be conveniently controlled by changing the concentration of the transition metal salt (0.2-10 mg/mL) and the mass ratio of the transition metal salt to the graphite oxide (0.2: 1-5: 1). The shape of holes of the traditional graphene sieve is difficult to regulate, and the holes are different in size and uneven in distribution, so that the average diffusion rate of ions is influenced, and the improvement of the multiplying power performance of the energy storage device is limited; meanwhile, the stability of the GM sheet structure is poor, the mechanical strength is obviously reduced, and the improvement of the flexibility and the mechanical stability of the energy storage device is not facilitated.

Then, 400mg of the GM was weighed and ultrasonically dispersed in 100mL of N, N-Dimethylformamide (DMF), 200mg of 4,4' -diamino-azobenzene was weighed and dissolved in 20mL of DMF, and added to the GM dispersion to react at 150 ℃ for 12 hours to obtain amino functionalized graphene sieve (NGM), and then cooled to room temperature, 300mg of Toluene Diisocyanate (TDI) was weighed and dissolved in 20mL of DMF, and the TDI solution was added dropwise to the NGM dispersion to ultrasonically disperse for 20 minutes and react at 20 ℃ for 12 hours.

Then, 105mg of Diethanolamine (DEOA) and 100mg of bis (4-hydroxyphenyl) disulfide (DPDS) were weighed out and dissolved in 40mL of DMF, and then added dropwise to the above NGM/TDI solution, and reacted at 20 ℃ for 12 hours with mechanical stirring, and then heated to 60 ℃ for continuous reaction for 24 hours, and the whole reaction was carried out under a nitrogen or argon atmosphere. And after the reaction is finished, directly pouring the reaction mixed solution into a beaker filled with a large amount of water for precipitation, filtering the precipitate, and then performing vacuum drying in a vacuum drying oven at the temperature of 80 ℃ to obtain the graphene sieve grafted hyperbranched polyurea-urethane composite material (NGM-HPU-SHG).

The hyperbranched polyurea-urethane composite material grafted by the graphene screen is used as a self-repairing binder to be applied to a lithium ion battery:

mixing cobaltosic oxide nanoparticles, acetylene black and the graphene sieve grafted hyperbranched polyurea-urethane composite material according to the mass ratio of 7:2:1, grinding, and performing ultrasonic treatment to obtain electrode slurry, thereby preparing the flexible electrode. Scratches are introduced into the surface of the flexible electrode, the electrode material can repair the wound quickly after illumination, and no obvious cracks are generated on the surface after 1000 times of repeated bending, as shown in figure 2, the flexible electrode material has good self-repairing capability and mechanical toughness.

Further, 1M LiPF using lithium plate as a comparative electrode₆And (FEC: DMC 1:1, V/V) is used as an electrolyte, and Celgard 3501 is used as a diaphragm to assemble the half-cell. The assembled lithium ion half-cell was tested for charge and discharge performance using a LAND-CT2001A tester with a set current density of 1000mAg^-1The setting voltage range is 0.01V-3.0V. As shown in FIG. 3, the assembled half cell was at 1000mAg^-1The first discharge capacity of the lithium secondary battery can reach 2476mAhg under the current density^-1Reversible capacity of 1104mAhg^-1，

Reversible capacity after 200 and 500 cycles was 1079 and 783mAhg, respectively^-1The capacity retention rates are 97.7% and 70.9%, respectively; while the first reversible capacity of the control sample, 2138mAhg, using conventional PVDF as the binder^-1Reversible capacity drop after 100 cycles of 431mAhg^-1The capacity retention was only 43.5%, as shown in fig. 4. The comparison shows that after the self-repairing binder is used, the specific capacity and the cycling stability of the battery are obviously improved.

FIG. 5 is a graph of battery rate performance using self-healing binders at 20 and 1000mA g current densities^-1The specific charging capacity is 1210 mAh g and 950mAh g respectively^-1The capacity retention rate after the current density is increased by 50 times is up to 78%, and the excellent rate performance of the capacity retention rate is derived from the nano structure of the electrode active material on one hand, and is attributed to the in-plane porous structure and the highly branched three-dimensional structure of the self-repairing binder on the other hand, so that the diffusion dynamic property of electrolyte ions is favorably improved, and the rate performance of the electrode material is improved.

Compared with the literature: pan et al (ACS appl. energy Mater.2018,1,6919-6926) use a self-repairing binder containing trisulfur carbon, carboxylic acid and amino functional groups to improve the cycle stability of the lithium-sulfur battery, the capacity retention rate of the lithium-sulfur battery after 100 cycles is 90.1%, the reversible capacities at 0.2C and 2.0C are 773.3 and 488mAh g < -1 >, and the capacity retention rate after 10 times of current density improvement is 63.1%.

Zhang et al prepared a silicon-sodium alginate-polyaniline composite by in situ polymerizationThe material has hydrogen bond self-healing effect on sodium alginate-polyaniline during the process of lithium insertion and lithium removal of silicon, and improves the cycling stability of the electrode, and the material is used at 200mA g^-1Lower initial capacity of about 1750mAh g^-1The capacity after 200 cycles of circulation is reduced to 1217.2mAh g^-1The retention rate is about 70%; at the same time, it is between 0.2 and 4A g^-1Capacity at current density 1897.5 and 373.8mAh g, respectively^-1The capacity retention rate after the current density is increased by 20 times is only 20%.

The comparison shows that the cycling stability and the rate capability of the self-repairing battery reported in the literature are obviously lower than those of the battery adopting the self-repairing binder NGM-HPU-SHG.

The above embodiments are merely illustrative of the technical solutions of the present invention. The graphene sieve grafted hyperbranched polyurethane self-repairing binder and the preparation and application thereof are not limited to the contents described in the above embodiments, but are subject to the scope defined by the claims. Any modification or supplement or equivalent replacement made by a person skilled in the art on the basis of this embodiment is within the scope of the invention as claimed in the claims.