Preparation of self-repairing polymer solid electrolyte containing zinc-imidazole coordination bond and lithium battery adopting electrolyte

Abstract

The invention belongs to the technical field of solid-state batteries, and particularly relates to preparation of a self-repairing polymer solid-state electrolyte containing a zinc-imidazole coordination bond and a lithium battery adopting the electrolyte. The preparation method comprises the following steps: reacting a reaction monomer containing a carbon-carbon double bond with a reaction monomer containing an imidazolyl group to prepare a comonomer A, and copolymerizing the comonomer A and a polyethylene glycol monomethyl ether acrylate monomer into a polymer containing a polyethylene glycol unit and a zinc ion-imidazolyl coordination network by using azodiisobutyronitrile as an initiator, and finally, mixing with zinc salt to prepare the self-repairing polymer solid electrolyte containing the zinc ion-imidazolyl coordinate bond. The prepared solid electrolyte has the advantages of simple synthesis, in-situ forming, high self-repairing efficiency and the like, can be self-adaptive to the surface of a lithium sheet in a cycle process after being applied to preparation of a high-performance polymer lithium battery, has super-strong self-repairing capability, prolongs the cycle life, and is expected to be widely applied to the field of intelligent lithium batteries.

Description

Technical Field

[0001] The present invention belongs to the technical field of solid-state batteries, and particularly relates to the preparation of a self-healing polymer solid electrolyte containing zinc-imidazole coordination bonds and a lithium battery using the electrolyte. Background Art

[0002] Polymer solid electrolytes (SPEs) have the advantages of being flexible, safe, and having good processability for large-scale roll-to-roll manufacturing processes, so they have become a highly anticipated approach to solving the safety problems of lithium-ion batteries. Among them, poly(ethylene oxide) (PEO)-based polymer electrolytes have been widely used due to their unique affinity for lithium ions. However, due to the strong crystallization ability of PEO at room temperature and its relatively high glass transition temperature (Tg), it has a low ionic conductivity and an unstable electrochemical window, which cannot meet the actual application requirements. Moreover, it will cause uneven deposition of lithium ions during operation, resulting in the generation of "dead lithium". Therefore, its effect on suppressing dendrite growth is limited. However, the irregular growth of dendrites will not only cause anode pulverization but also pierce the solid electrolyte, leading to internal short circuits in the battery, which will cause irreversible damage to the cycle life of LMBs.

[0003] In nature, when organisms are damaged, they will use their unique self-healing function to automatically heal wounds, thus avoiding secondary injuries. Inspired by this, at present, self-healing materials are classified into external and intrinsic types according to their sources. The external type refers to storing the repair liquid in microcapsules or microfibers and dispersing them in the material. When the material is damaged, the repair liquid flows out for repair. Intrinsic self-healing materials directly incorporate reversible bonds (such as DA bonds, Schiff bases, and disulfide bonds) into the molecular chain and utilize the "opening-reconnection" characteristics of the reversible bonds to complete the self-healing process. Among them, this type of solid self-healing polymer electrolyte based on intrinsic self-healing materials can only achieve self-healing under specific conditions, and these repair conditions are quite different from the operating environment of LMBs, resulting in the inability to repair the damaged electrolyte in a timely manner. This characteristic has hindered the further development of solid self-healing polymer electrolytes.

[0004] Compared with these exogenous solid self-healing polymer electrolytes that require external stimuli to achieve the repair function, the endogenous solid self-healing polymer electrolyte materials without external stimuli have more advantages. The dynamic covalent bonds (such as hydrogen bonds, ion-ion interactions, electrostatic interactions, ion-dipole interactions, etc.) relied on by such materials can be regarded as dynamic bonds that are constantly exchanging at room temperature, and have fast and efficient repair capabilities, thus ensuring that the SPE can be repaired in time when damaged during operation and inhibiting the uneven deposition of lithium ions. However, the ionic conductivity of these solid self-healing polymer electrolytes at room temperature is still low, and the operating temperature is still harsh. For the above reasons, developing a solid electrolyte with high ionic conductivity and self-healing conditions matching the battery operating conditions has broad application prospects. Summary of the Invention

[0005] In order to overcome the deficiencies of the above-mentioned prior art, the present invention proposes a self-healing polymer solid electrolyte containing zinc ion-imidazole-based coordination bonds. This self-healing polymer electrolyte has the advantages of simple synthesis, in-situ forming, high self-healing efficiency, etc. After being applied to the preparation of high-performance polymer lithium batteries, it can adapt to the surface of the lithium sheet during cycling and extend the cycle life, and is expected to be widely used in the field of intelligent lithium batteries.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] The first aspect of the present invention provides a preparation method of a self-healing polymer solid electrolyte containing zinc-imidazole coordination bonds, and this method includes the following steps:

[0008] S1. React a reaction monomer containing a carbon-carbon double bond and a reaction monomer containing an imidazole group in N,N-dimethylformamide to prepare a copolymer monomer A;

[0009] S2. Add the copolymer monomer A (providing a coordination receptor), a polyethylene glycol monomethyl ether acrylate monomer (copolymer monomer B, providing a lithium ion transport channel) into N,N-dimethylformamide, and then add azobisisobutyronitrile (AIBN) as an initiator, and prepare a polymer containing a polyethylene glycol unit and a zinc ion-imidazole-based coordination network through copolymerization reaction;

[0010] S3. Add a zinc salt (providing a coordination center) and a lithium salt (assisting lithium ion transport) to the polymer containing a polyethylene glycol unit and a zinc ion-imidazole-based coordination network, mix evenly and then dry to obtain a self-healing polymer solid electrolyte containing zinc-imidazole coordination bonds.

[0011] Preferably, the reaction monomer containing a carbon-carbon double bond is one or more of the following compounds:

[0012]

[0013] Preferably, the reaction monomer containing an imidazole group is one or two of the following compounds:

[0014]

[0015] Preferably, the reaction temperature of S1 is 50 - 60 °C, the time is 5 - 7 h, and after the reaction, dialysis and drying treatments are carried out.

[0016] Preferably, the polyethylene glycol monomethyl ether acrylate monomer is selected from polyethylene glycol monomethyl ether acrylate, and the molecular weight is 200 - 100000. More preferably, the molecular weight is 200 - 1000.

[0017] Preferably, S2 is carried out in an argon atmosphere, the reaction temperature is 65 - 75 °C, the time is 10 - 15 h, and after the reaction, rotary evaporation, dialysis, and drying treatments are carried out.

[0018] Preferably, the zinc salt is one or several of zinc nitrate hexahydrate, zinc sulfate, zinc oxalate, and zinc chloride.

[0019] Preferably, the lithium salt is LiClO 4 , LiPF 6 , LiCF 3 SO 3 , LiBF 4 , LiAsF 6 , LiSbF 6 , LiN(CF 3 SO 2 ) 2 , LiCF 3 CF 2 SO 3 , lithium bis(trifluoromethanesulfonyl)imide, lithium difluoro(oxalato)borate, or lithium (propane - 1,2 - diolate)borate, or one or several of them.

[0020] In the second aspect of the present invention, a self - healing polymer solid electrolyte containing a zinc - imidazole coordination bond prepared by the preparation method described in the first aspect is provided.

[0021] In the third aspect of the present invention, the application of the self - healing polymer solid electrolyte containing a zinc - imidazole coordination bond described in the second aspect in a lithium battery is provided.

[0022] In the fourth aspect of the present invention, a lithium battery is provided. The lithium battery includes the self - healing polymer solid electrolyte containing a zinc - imidazole coordination bond described in the second aspect. Its preparation method is as follows: first, dissolve the self - healing polymer solid electrolyte containing a zinc - imidazole coordination bond described in the second aspect in dimethyl carbonate, then drop the solution onto a lithium sheet, and after the solvent volatilizes, in - situ forming is achieved on the lithium sheet and then the battery is assembled.

[0023] The present invention grafts and composites a monomer containing polyethylene glycol and a zinc ion-imidazole-based coordination network by means of radical polymerization. On the one hand, the addition of the dynamic network not only destroys the ordered structure of PEG, reduces the crystallinity inside PEG, and due to the repulsive interaction between Zn 2+ and Li + , it accelerates the conduction rate of Li + in the composite polymer network, greatly improving the ionic conductivity of the solid electrolyte. On the other hand, the coordination bond formed by zinc ions and imidazole groups can be regarded as a continuously exchanging dynamic bond at room temperature. The excellent fluidity endows the composite polymer network with the characteristics of rapid self-adaptive coating of irregular lithium dendrites and rapid wound healing. Finally, using the characteristics of the coordination bond, it is in-situ formed on the surface of the electrode, enhancing the adhesion between the electrolyte and the electrode, protecting the lithium anode and the solid electrolyte, thereby achieving dual repair and extending the battery cycle life.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] The present invention discloses a preparation method of a self-healing polymer solid electrolyte containing zinc ion-imidazole-based coordination bonds. First, a copolymer monomer A is prepared by reacting a reaction monomer containing a carbon-carbon double bond and a reaction monomer containing an imidazole group. Then, using azobisisobutyronitrile (AIBN) as an initiator, copolymer monomer A and a polyethylene glycol monomethyl ether acrylate monomer (copolymer monomer B) are copolymerized into a polymer containing a polyethylene glycol unit and a zinc ion-imidazole-based coordination network. Finally, it is mixed with a zinc salt to obtain a solid electrolyte. The obtained solid electrolyte has the advantages of simple synthesis, in-situ forming, high self-healing efficiency, etc. After being applied to the preparation of high-performance polymer lithium batteries, it can be self-adaptive to the surface of the lithium sheet during the cycling process and has super strong self-healing ability at room temperature, thereby extending the cycle life and is expected to be widely used in the field of intelligent lithium batteries. Specifically, the present invention has the following advantages:

[0026] (1) The cross-linking points of the coordination bonds introduced in the present invention (the coordination bonds formed by zinc ions and imidazole groups), on the one hand, break the disordered structure inside the polymer, inhibit the crystallization of PEG segments, increase the segment flexibility, reduce the glass transition temperature, and accelerate the transport of lithium ions in the segments. On the other hand, the introduction of inorganic metal ions further enhances the transport rate of lithium ions, thereby providing a more stable electrochemical window.

[0027] (2) The coordination bond composed of zinc ions and imidazole groups is a continuously exchanging dynamic bond at room temperature. Introducing such dynamic bonds into the polymer solid electrolyte endows the polymer solid electrolyte with super strong self-healing ability at room temperature, which is more compatible with the operating conditions of the battery, thereby extending the service life of the battery.

[0028] (3) According to the characteristics of the coordination bond, that is, the coordination center can selectively coordinate according to the binding energy with each ligand. During the introduction of the lithium salt into the polymer, by utilizing the characteristic that Zn 2+ has a stronger coordination ability with small molecules of the lithium salt solvent, the re - shaping of the electrolyte on the electrode surface is realized, and then the in - situ shaping effect is achieved. Thus, not only the interfacial impedance between the electrolyte and the electrode sheet is reduced, but also the adhesion between the electrolyte and the electrode sheet is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a reaction flow chart for preparing a self - healing polymer solid electrolyte containing zinc ion - imidazole - based coordination bonds.

[0030] Figure 2 It is the nuclear magnetic resonance hydrogen spectrum of glycerol methacrylate, comonomer A and the final product used in Example 1.

[0031] Figure 3 It is the X - ray photoelectron spectrum of carbon atoms in the polymer before cross - linking in Example 1.

[0032] Figure 4 It is the linear sweep voltammogram of the product in Example 1 before and after adding zinc ions.

[0033] Figure 5 It is the optical picture of the product in Example 1 being repaired under external force damage.

[0034] Figure 6 It is the impedance spectrum of the lithium batteries assembled in Examples 1, 2, 3, and 4.

[0035] Figure 7 It is the impedance spectrum of the lithium batteries assembled in Example 1 and Comparative Example 1.

[0036] Figure 8 It is the galvanostatic charge - discharge cycle diagram of the lithium batteries assembled in Example 1 and Comparative Example 1 after constant - current charge - discharge at a current density of 0.1 mA / cm 2 of.

[0037] Figure 9 It is the impedance spectrum of the lithium batteries assembled in Example 1 and Comparative Example 2. DETAILED DESCRIPTION OF THE INVENTION

[0038] The following further describes the specific embodiments of the present invention. It should be noted here that the description of these embodiments is for helping to understand the present invention, but does not constitute a limitation to the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0039] In the experimental methods of the following examples, unless otherwise specified, they are all conventional methods. Unless otherwise specified, the test materials used in the following examples can all be obtained through conventional commercial channels.

[0040] Example 1: Preparation of a self-healing polymer solid electrolyte containing zinc-imidazole coordination bonds and a lithium battery using this electrolyte

[0041] 1. Preparation of a self-healing polymer solid electrolyte containing zinc ion-imidazole group coordination bonds

[0042] The polymer electrolyte is composed of comonomer A, comonomer B, initiator, zinc salt, and lithium salt. Its preparation process is as Figure 1 shown, and its preparation method includes the following steps:

[0043] (1) Synthesis of comonomer A containing a carbon-carbon double bond and an imidazole group:

[0044] Weigh 2.48 g (20 mmol) of glycidyl methacrylate (GMA) and 2.5 g (20 mmol) of 1-(3-aminopropyl)imidazole (N3AIM), dissolve them in 10 mL of DMF, stir magnetically at 50 °C for 6 h, rotary evaporate to remove most of the DMF, and then dialyze in an ethanol solution for 48 h. After drying, comonomer A: GMA-N3AIM is obtained.

[0045] (2) Synthesis of a polymer containing PEG and an imidazole group:

[0046] Based on the above product, add an appropriate amount of methoxypolyethylene glycol acrylate (PEGMEA, molecular weight 480) to step (1) at a molar ratio of PEG:IM = 2:1 (i.e., the molar ratio of PEGMEA to GMA-N3AIM), continue to add 70 mL of DMF, and then pour them all into a three-necked flask. Separately weigh azobisisobutyronitrile (AIBN) (1 wt.%) and dissolve it in 20 mL of DMF, and add it to a separatory funnel. Then insert the separatory funnel onto the three-necked flask, heat it to 70 °C with an oil bath, and purge the air in the reaction vessel with Ar. After 20 min, open the separatory funnel to slowly drip the AIBN solution into the flask, and react for 12 h. After the reaction, rotary evaporate to remove most of the solvent, add 50 mL of anhydrous ethanol to dissolve, then add the ethanol solution containing the product into a dialysis bag (molecular weight 3500), and dialyze in an ethanol solution for 48 h to remove unreacted small molecules. Finally, dry it in a vacuum oven at 60 °C to obtain the product PEG-g-(GMA-N3AIM).

[0047] (3) Synthesis of a cross-linked polymer:

[0048] With imidazole group:Zn 2+Weigh Zn(NO 3 ) 2 ·6H 2 O in 120 mL of DMF solution, then add an ethanol solution containing the PEG-g-(GMA-N3AIM) polymer in the corresponding ratio. After completely drying the solution in a blast drying oven at 60 °C, transfer it to a vacuum drying oven at 50 °C and dry for 12 h to obtain the final product: PEG-g-(GMA-N3AIM)-Zn 2+ .

[0049] 2. Preparation of lithium battery

[0050] Weigh and dissolve the above-mentioned cross-linked product and lithium hexafluorophosphate in a solution of dimethyl carbonate (DMC) according to the molar ratio of EO:Li+ = 10:1 (just completely dissolve). Use a pipette to drop the solution on the lithium sheet, heat it in a glove box to volatilize the solvent, and in-situ generate a solid electrolyte on the surface of the lithium sheet to assemble the Li||SPE||Li battery.

[0051] From Figure 2 , it can be seen that in the raw material, GMA shows a stretching vibration peak of H on the epoxy group at the position of 3.4 ppm. After reacting with -NH2 in N3AIM, the peak shown by H on the epoxy basically disappears, and at the same time, a stretching vibration peak of H on the imidazole group appears at 7 - 8 ppm, proving that GMA and N3AIM have basically completely reacted. In addition, XPS testing of the C1s orbital in the free radical reaction product shows ( Figure 3 ): In addition to the C-C, C-O, and C=O peaks of itself, the presence of the COO- group peak is also detected, which proves that the free radical polymerization reaction between PEG and GMA-N3AIM has occurred successfully.

[0052] From Figure 4 , it can be seen that after forming the Li||SPE||S battery with the polymer before and after cross-linking, when measuring the electrochemical window, compared with PEG-g-(GMA-N3AIM)-Zn 2+ , PEG-g-(GMA-N3AIM) shows a large fluctuation at 4.7 V, proving that the addition of the cross-linking agent is more conducive to the electrochemical stability of the solid electrolyte.

[0053] From Figure 5 , it can be seen that the cross-linked polymer can basically repair the wound within 5 min and completely repair it within 15 min. The strong self-healing ability ensures that when the SPE is pierced by lithium dendrites during operation, it can quickly heal to enable the battery to operate stably and extend the service life of the battery.

[0054] Example 2: Preparation of a Self-healing Polymer Solid Electrolyte Containing Zinc-Imidazole Coordination Bonds and a Lithium Battery Using the Electrolyte

[0055] 1. Preparation of a Self-healing Polymer Solid Electrolyte Containing Zinc Ion-Imidazole Group Coordination Bonds

[0056] (1) Synthesis of copolymer monomer A containing carbon-carbon double bonds and imidazole groups:

[0057] Same as step (1) of Example 1.

[0058] (2) Synthesis of a polymer containing PEG and imidazole groups:

[0059] Based on the above product, add an appropriate amount of methoxypolyethylene glycol acrylate (PEGMEA) to step (1) at a molar ratio of PEG:IM = 1:1. Then continue to add 50 mL of DMF, and pour them into a three-necked flask together. Additionally, weigh azobisisobutyronitrile (AIBN) (1 wt.%) and dissolve it in 20 mL of DMF, and add it to a separatory funnel. Then insert the separatory funnel onto the three-necked flask, and heat it to 70 °C in an oil bath. Pass Ar to remove the air in the reaction vessel. After 20 min, open the separatory funnel to slowly drip the AIBN solution into the flask, and react for 12 h. After the reaction, perform rotary evaporation to remove most of the solvent, add anhydrous ethanol to dissolve it, then add the ethanol solution containing the product to a dialysis bag (molecular weight 3500), and dialyze in the ethanol solution for 48 h to remove unreacted small molecules. Finally, dry it in a vacuum oven at 60 °C to obtain the product PEG-g-(GMA-N3AIM).

[0060] (3) Synthesis of cross-linked polymer:

[0061] Same as step (3) of Example 1.

[0062] 2. Preparation of a lithium battery

[0063] Same as Example 1.

[0064] Example 3: Preparation of a Self-healing Polymer Solid Electrolyte Containing Zinc-Imidazole Coordination Bonds and a Lithium Battery Using the Electrolyte

[0065] 1. Preparation of a Self-healing Polymer Solid Electrolyte Containing Zinc Ion-Imidazole Group Coordination Bonds

[0066] (1) Synthesis of copolymer monomer A containing carbon-carbon double bonds and imidazole groups:

[0067] Same as step (1) of Example 1.

[0068] (2) Synthesis of a polymer containing PEG and imidazole groups:

[0069] Based on the above product, polyethylene glycol monomethyl ether acrylate (PEGMEA) was added to step (1) in a molar ratio of PEG:IM = 1.5:1, and then 60 mL of DMF was added continuously. Then, they were poured into a three-necked flask together. Additionally, azobisisobutyronitrile (AIBN) (1 wt.%) was weighed and dissolved in 20 mL of DMF, and this solution was added to a separatory funnel. Subsequently, the separatory funnel was inserted onto the three-necked flask, and the oil bath was heated to 70 °C. Ar was introduced to remove all the air in the reaction vessel. After 20 min, the separatory funnel was opened to slowly drip the AIBN solution into the flask, and the reaction was carried out for 12 h. After the reaction ended, rotary evaporation was performed to remove most of the solvent, and then anhydrous ethanol was added for dissolution. The ethanol solution containing the product was added to a dialysis bag (molecular weight 3500) and dialyzed in the ethanol solution for 48 h to remove the unreacted small molecules. Finally, it was dried in a vacuum oven at 60 °C to obtain the product PEG-g-(GMA-N3AIM).

[0070] (3) Synthesis of crosslinked polymer:

[0071] Same as step (3) of Example 1.

[0072] 2. Preparation of lithium battery

[0073] Same as Example 1.

[0074] Example 4: Preparation of a self-healing polymer solid electrolyte containing zinc-imidazole coordination bonds and a lithium battery using this electrolyte

[0075] 1. Preparation of a self-healing polymer solid electrolyte containing zinc ion-imidazole group coordination bonds

[0076] (1) Synthesis of copolymer monomer A containing carbon-carbon double bond and imidazole group:

[0077] Same as step (1) of Example 1.

[0078] (2) Synthesis of polymer containing PEG and imidazole group:

[0079] Based on the above product, polyethylene glycol monomethyl ether acrylate (PEGMEA) was added to step (1) at a molar ratio of PEG:IM = 2.5:1. An appropriate amount of PEGMEA was added, and then 80 mL of DMF was added continuously. Then, the mixture was poured into a three-necked flask. Additionally, azobisisobutyronitrile (AIBN) (1 wt.%) was weighed and dissolved in 20 mL of DMF, and this solution was added to a separatory funnel. After that, the separatory funnel was inserted into the three-necked flask, and the temperature was raised to 70 °C using an oil bath. Ar was introduced to remove all the air in the reaction vessel. After 20 min, the separatory funnel was opened to slowly drip the AIBN solution into the flask, and the reaction was carried out for 12 h. After the reaction ended, rotary evaporation was performed to remove most of the solvent. Then, anhydrous ethanol was added for dissolution. The ethanol solution containing the product was added to a dialysis bag (molecular weight 3500), and dialysis was carried out in the ethanol solution for 48 h to remove unreacted small molecules. Finally, it was dried in a vacuum oven at 60 °C to obtain the product PEG-g-(GMA-N3AIM).

[0080] (3) Synthesis of crosslinked polymer:

[0081] Same as step (3) of Example 1.

[0082] 2. Preparation of lithium battery

[0083] Same as Example 1.

[0084] From Figure 6 it can be seen that as the molar ratio of GMA:N 3 IM increases, the mechanical properties of the polymer decrease, the content of PEO increases, which makes the flexibility of the SPE increase and the number of Li + transport channels increase, and the interfacial impedance of the SPE gradually decreases. When the ratio increases to 2.5, it is found that the interfacial impedance of the monomer ratio in the SPE from 2 to 2.5 does not decrease regularly, but increases from 350 Ohm to 480 Ohm, an increase of 120 Ohm. This is because it is not only PEO that transports lithium ions inside the SPE. The ion channels composed of Zn 2+ also contribute to the Li + transport process. It is precisely because of the decrease in the Zn 2+ content that the interfacial impedance of 2.5:1 is higher than that of 2:1.

[0085] Comparative Example 1: Preparation of a self-healing polymer solid electrolyte containing zinc-imidazole coordination bonds and a lithium battery using this electrolyte

[0086] 1. Preparation of a self-healing polymer solid electrolyte containing zinc ion-imidazole group coordination bonds

[0087] Same as Example 1.

[0088] 2. Preparation of lithium battery

[0089] After the polymer electrolyte was in-situ formed on the surface of the lithium sheet according to the method of Example 1, a wound with a certain thickness was cut with a knife to simulate the working conditions of the SPE. After placing it in an anhydrous and oxygen-free environment for 2 h, the Li||SPE||Li battery was assembled.

[0090] In Figure 7 in order to prove the strong self-healing performance of the SPE, after a wound with a certain thickness was cut in the polymer with a knife, the working conditions of the SPE were simulated and placed in an anhydrous and oxygen-free environment. After 2 h, the interfacial impedance was measured, and it was found that the interfacial impedance between the self-healed SPE and Li increased by only 310 Ohm compared with that before repair, which was still within an acceptable range.

[0091] In Figure 8 in, the overpotential of the self-healed sample at the beginning (24 h - 32 h) was 0.4 V. However, as the continuous transfer of lithium ions occurred, when the working time was 743 - 751 h, the polarization voltage had decreased to 0.27 V. When the battery was cycled for a long time to about 1300 h, the overpotential decreased to 0.21 V. This proved that this cross-linked polymer had unique advantages in the process of fitting with the Li interface. While maintaining high self-healing performance, it could continuously improve the interfacial performance between the SPE and Li during the operation of the battery. And the self-healed SPE showed stronger mechanical properties, making the cycle time after repair much longer than that of the sample before repair, up to 1400 h. This was because the high-efficiency self-healing of the sample played a timely repair role in the process of lithium plating - delithiation, which was conducive to the timely repair after the irregular lithium dendrites pierced the SPE, thus preventing the further growth of lithium dendrites.

[0092] Comparative Example 2: Preparation of a self-healing polymer solid electrolyte containing zinc-imidazole coordination bonds and a lithium battery using the electrolyte

[0093] 1. Preparation of a self-healing polymer solid electrolyte containing a coordination bond of zinc ions - imidazole groups

[0094] Same as Example 1.

[0095] 2. Preparation of a lithium battery

[0096] The polymer electrolyte obtained in step (1) was mixed with lithium hexafluorophosphate and then cut into circular pieces the size of lithium sheets, which were directly assembled with lithium sheets into lithium batteries and compared with the battery constructed in Example 1, and impedance spectrogram tests were carried out together.

[0097] Figure 9 It was shown that after assembling the Li||SPE||Li batteries by two methods respectively, the interfacial impedance of the non-in-situ forming was 900 Ohm, which was much higher than 350 Ohm of the in-situ forming, proving that in-situ forming played an irreplaceable role in reducing the interfacial impedance.

[0098] The above has described the embodiments of the present invention in detail, but the present invention is not limited to the described embodiments. For those skilled in the art, without departing from the principles and spirit of the present invention, various changes, modifications, substitutions, and variations to these embodiments still fall within the protection scope of the present invention.

Claims

1. A method for preparing a self-healing polymer solid electrolyte containing a zinc-imidazole coordination bond, characterized in that: The following steps are involved: S1, reacting a reactive monomer containing a carbon-carbon double bond and a reactive monomer containing an imidazole group in N,N-dimethylformamide to prepare a comonomer A; S2, adding comonomer A and polyethylene glycol monomethyl ether acrylate monomer to N,N-dimethylformamide, and then adding azobisisobutyronitrile as an initiator, and obtaining a polymer containing polyethylene glycol units and a zinc ion-imidazole coordination network after copolymerization; S3. Add zinc salt and lithium salt to the polymer containing polyethylene glycol units and zinc ion-imidazole coordination network, mix well and dry to obtain a self-healing polymer solid electrolyte containing zinc-imidazole coordination bonds.

2. The method for preparing a self-healing polymer solid electrolyte containing zinc-imidazole coordination bonds according to claim 1, characterized in that: The reactive monomer containing a carbon-carbon double bond is one or more of the following compounds:

3. The method for preparing a self-healing polymer solid electrolyte containing zinc-imidazole coordination bonds according to claim 1, characterized in that: The reactive monomer containing imidazole group is one or two of the following compounds:

4. The method for preparing a self-healing polymer solid electrolyte containing zinc-imidazole coordination bonds according to claim 1, characterized in that: The reaction temperature of S1 is 50-60°C, the reaction time is 5-7h, and the reaction is followed by dialysis and drying.

5. The method for preparing a self-healing polymer solid electrolyte containing zinc-imidazole coordination bonds according to claim 1, characterized in that: The polyethylene glycol monomethyl ether acrylate monomer is selected from polyethylene glycol monomethyl ether acrylate and has a molecular weight of 200 to 100,000.

6. The method for preparing a self-healing polymer solid electrolyte containing zinc-imidazole coordination bonds according to claim 1, characterized in that: S2 is carried out under an argon environment, with a reaction temperature of 65-75°C and a reaction time of 10-15 hours. After the reaction, rotary evaporation, dialysis and drying are performed.

7. The method for preparing a self-healing polymer solid electrolyte containing zinc-imidazole coordination bonds according to claim 1, characterized in that: The zinc salt is one or more of zinc nitrate hexahydrate, zinc sulfate, zinc oxalate, and zinc chloride; the lithium salt is one or more of LiClO4, LiPF6, LiCF3SO3, LiBF4, LiAsF6, LiSbF6, LiN(CF3SO2)2, LiCF3CF2SO3, lithium bis(trifluoromethanesulfonyl)imide, lithium difluoro(oxalate)borate, or lithium (malonic acid)borate.

8. A self-healing polymer solid electrolyte containing zinc-imidazole coordination bonds prepared by the preparation method according to any one of claims 1 to 7.

9. Use of the self-healing polymer solid electrolyte containing zinc-imidazole coordination bonds as claimed in claim 8 in lithium batteries.

10. A lithium battery, characterized in that: The lithium battery comprises the self-healing polymer solid electrolyte containing zinc-imidazole coordination bonds as claimed in claim 8, and its preparation method is: first dissolving the self-healing polymer solid electrolyte containing zinc-imidazole coordination bonds as claimed in claim 8 in dimethyl carbonate, then dripping the solution on a lithium sheet, and after the solvent evaporates, in-situ molding is performed on the lithium sheet and then the battery is assembled.

Images