An ethanol aluminum composite polymer electrolyte membrane, a preparation method thereof, and application of the same in a battery and an assembling process of the battery

Abstract

The application relates to the technical field of chemical batteries, in particular to an ethanol-aluminum composite polymer electrolyte film, a preparation method thereof, application of the ethanol-aluminum composite polymer electrolyte film in batteries and a battery assembling process. The ethanol-aluminum composite polymer electrolyte film comprises a polymer and ethanol aluminum; the polymer is a polymer containing an ester group or / and an ether bond in a structure; the polymer is a polyethylene oxide or a polyethylene oxide derivative; and the polyethylene oxide derivative is obtained by photopolymerization of small-molecule monomers. The ethanol-aluminum composite polymer electrolyte film is applied to a battery, the interface compatibility is enhanced, fast and orderly transmission can be realized, and the cycle stability is good.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of chemical batteries, in particular to an ethanol aluminum composite polymer electrolyte membrane, a preparation method thereof, application of the ethanol aluminum composite polymer electrolyte membrane in a battery, and a battery assembly process. BACKGROUND

[0002] Lithium metal batteries (LMB) are considered as the ideal choice for the next generation of energy storage systems due to their ultra-high energy density. However, the practical application of LMB is severely limited by safety issues due to the uncontrollable growth of lithium dendrites when cycled in organic liquid electrolytes (LE). To solve this problem, solid (such as ceramic and solid polymer) and quasi-solid (such as gel polymer) electrolytes are considered as promising alternatives to improve the safety and performance of LMB. Although ceramic electrolytes are considered to be able to prevent lithium dendrites from penetrating due to their mechanical rigidity, studies have shown that lithium dendrites can grow along the grain boundaries of ceramic electrolytes. In addition, there is a high and unstable interfacial resistance between the solid electrode and the ceramic electrolyte, which leads to the problem of slow interfacial charge transfer. In contrast, solid polymer electrolytes can be used to improve their interfacial compatibility with solid electrodes.

[0003] Among various polymer materials, polyethylene oxide (PEO)-based solid-state polymer electrolytes (SPE) have been the focus of long-term research. However, its low ionic conductivity, low mechanical strength and insufficient oxidation resistance at room temperature limit its application in LMB. Currently, in order to improve the performance of PEO-based SPE at room temperature, a plasticizer, i.e. a small molecule liquid solvent, is usually added to the polymer matrix to prepare a PEO-based gel polymer electrolyte (GPE) with high ionic conductivity. However, the addition of plasticizers will weaken the mechanical strength of GPE and make it difficult to inhibit the growth of lithium dendrites. Therefore, a common method to improve the ionic conductivity and stability of polymer electrolytes is to add ceramic fillers to the PEO matrix to form a composite SPE. However, due to the differences in structure and performance between inorganic fillers and organic polymers, the interfacial compatibility between the two is poor, which not only increases the internal interfacial impedance, but also easily leads to the aggregation of fillers, hindering the construction of lithium ion conduction channels, and ultimately leading to uneven deposition of lithium ions on the negative electrode.

[0004] To improve the interfacial compatibility between organic matrix and fillers, current research mainly forms effective connections through chemical bonds. For example, the team of Academician Zhang Suojing of the Chinese Academy of Sciences uses silane coupling agent (3-chloropropyl) trimethoxysilane (CTMS) as a “bridge” to connect ceramic filler LGPS and polyethylene glycol (PEG) through chemical bonds, to build a “high-speed channel” for lithium ion transmission, and to be compounded with PEO and lithium bis (trifluoromethyl sulfonyl) imide (LiTFSI) to prepare a composite solid electrolyte with excellent performance [1] . Archer et al. achieved covalent connection of PEO with SiO2 inorganic nanoparticles by amino functionalization of PEO, to prepare a soft colloidal glass composite solid electrolyte [2] . In addition, Professor Robert K. Y. Li introduced vinyl carbonate and generated ion-conducting ether oxygen oligomers through ring-opening polymerization reaction by using LiOH / Li2CO3 contaminants on the surface of LLZTO as initiators, to improve the compatibility of particles and PEO matrix [3] . Although the above research improves the interfacial compatibility by adding small organic molecules or organic functional groups as “bridges”, the operation is complex and the conditions are harsh, and direct combination of fillers and organic matrix cannot be achieved.

[0005] For example, Chinese Patent CN117467164A discloses a polymer solution, gel electrolyte, sodium ion battery, gel polymer separator, and preparation method, which has the advantages of improving the ionic conductivity and interfacial compatibility of the gel polymer electrolyte by introducing nano Si / Ti oxide compounds through in-situ hydrolysis and polycondensation method. However, the method of increasing compatibility is complex, and other metal impurities are introduced.

[0006] In addition, due to the low oxidative decomposition potential and disordered lithium ion transport path of PEO-based SPE, it is difficult to be compatible with high-voltage cathodes such as LiNi 0.6 Co 0.2 Mn 0.2 O2 (NCM622), which is a major obstacle to commercial application. Although direct contact between NCM cathode and PEO can be avoided by adding a coating on the surface of the cathode or by compounding PEO with polyacrylonitrile (PAN), or the intrinsic structural stability of PEO can be enhanced through molecular structure design to adapt to NCM cathode, it is still a major challenge to simultaneously enhance the stability of electrode / electrolyte interface and adjust the ionic conduction behavior of the composite polymer electrolyte through molecular structure engineering design.

[0007] Therefore, it is urgent to provide an electrolyte membrane which has a simple preparation method, direct combination between fillers and organic matrix, high interfacial compatibility, and can match high voltage and significantly inhibit the formation of dendrites, and to apply it to a battery.

[0008] Reference:

[0009] [1]Pan K, Zhang L, Qian W, et al. A Flexible Ceramic / Polymer Hybrid Solid Electrolyte for Solid-State Lithium Metal Batteries. 2020, 32(17): e2000399.

[0010] [2]Choudhury S, Stalin S, Deng Y, et al. Soft colloidal glasses as solid-state electrolytes. 2018, 30(17): 5996-6004.

[0011] [3]He K, Cheng S.H, Hu J, et al. In-Situ Intermolecular Interaction in Composite Polymer Electrolyte for Ultralong Life Quasi-Solid-State Lithium Metal Batteries. 2021, 133: 12223-12230. SUMMARY

[0012] Based on the deficiencies of the prior art, the present application aims to provide an electrolyte membrane with a simple preparation method, direct combination between fillers and organic matrix, high interfacial compatibility, and the ability to match high voltage and significantly inhibit dendrite formation, and its application in batteries.

[0013] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0014] On the one hand, the present application provides an ethanol aluminum composite polymer electrolyte membrane, which comprises a polymer and ethanol aluminum.

[0015] The polymer is a polymer containing an ester group or / and an ether bond in its structure; the polymer is a polyethylene oxide or a polyethylene oxide derivative; the ethanol aluminum can be obtained by commercial purchase or self-preparation; the polyethylene oxide derivative is obtained by photopolymerization of small molecule monomers.

[0016] Preferably, the small molecule monomer is selected from one or more of polyethylene glycol diacrylate, triethylene glycol diacrylate, polytetraethylene glycol diacrylate, tetraethylene glycol diacrylate, 1,3-dioxolane, polyethylene glycol dimethyl ether, ε-caprolactone and ethoxylated trimethylolpropane triacrylate.

[0017] Preferably, the polymer of polyethylene oxide is PEO.

[0018] More preferably, the small molecule monomer is selected from PEGDA, TEGDA, TEPTA and ε-CL.

[0019] In another aspect, the application also provides a preparation method of the aluminum ethoxide composite polymer electrolyte membrane, comprising the following steps:

[0020] A. Synthesis of aluminum ethoxide membrane

[0021] (1) mixing aluminum powder and metal powder to melt, obtaining alloy sheet in molten state;

[0022] (2) cooling the alloy sheet in step (1), and then reacting with anhydrous ethanol to obtain an aluminum ethoxide gel;

[0023] (3) washing by-products and filtering the aluminum ethoxide gel obtained in step (2) to obtain an aluminum ethoxide membrane;

[0024] B. Synthesis of aluminum ethoxide composite polymer electrolyte membrane

[0025] S1. mixing polymer monomers and a photoinitiator to obtain a mixed solution under an inert atmosphere, and then mixing and stirring the mixed solution and a base electrolyte to obtain a light-cured precursor solution;

[0026] S2. placing the aluminum ethoxide membrane obtained in step A on a negative electrode, adding the light-cured precursor solution obtained in S1, and performing ultraviolet irradiation or drying, thereby obtaining the aluminum ethoxide composite polymer electrolyte membrane.

[0027] Preferably, the mixing ratio of the aluminum powder and lithium powder in step (1) of A is 2.5-3.5:0.85; the melting temperature is 750-850°C, and the time is 15-25 min.

[0028] More preferably, the mixing ratio of the aluminum powder and lithium powder in step (1) of A is 3:0.85; the melting temperature is 800°C, and the time is 20 min.

[0029] Preferably, the mass-volume ratio of the alloy sheet and anhydrous ethanol in step (2) of A is 0.11-0.12 g:15-25 mL; and the reaction time is 25-35 h.

[0030] More preferably, the mass-volume ratio of the alloy sheet and anhydrous ethanol in step (2) of A is 0.115 g:20 mL; and the reaction time is 30 h.

[0031] Preferably, the photoinitiator in step (1) of B is phenyl bis(2,4,6-trimethylbenzoyl) phosphine oxide (BAPO).

[0032] Preferably, the mass fraction of the phenyl bis(2,4,6-trimethylbenzoyl) phosphine oxide in the above-mentioned monomer is 1wt%.

[0033] Preferably, the base electrolyte in step S1 in B comprises an electrolyte salt and a solvent.

[0034] Preferably, the weight ratio of the above-mentioned mixed solution to the base electrolyte is 1-10:10.

[0035] Preferably, the time of the ultraviolet irradiation in step S1 in B is 20s.

[0036] Preferably, the drying in step S2 in B is incubated at 50℃ for 4h.

[0037] Preferably, the dropwise amount of the photo-driven precursor in step S2 in B is 20-30μL.

[0038] In still another aspect, the application further provides a use of the above-mentioned aluminum ethoxide composite polymer electrolyte membrane in the preparation of a battery.

[0039] Preferably, the battery is a lithium battery or a sodium battery.

[0040] Preferably, the battery is composed of a negative electrode, the aluminum ethoxide composite polymer electrolyte membrane and a positive electrode.

[0041] In still another aspect, the application further provides an assembling process of the above-mentioned battery, characterized in that it comprises the following steps:

[0042] (1) combining the prepared aluminum ethoxide composite polymer electrolyte membrane with a negative electrode;

[0043] (2) using a commercial positive electrode as the positive electrode material;

[0044] (3) assembling to obtain a battery.

[0045] Compared with the prior art, the application has the following beneficial effects:

[0046] (1) The aluminum ethoxide of the application contains abundant unsaturated coordination sites of aluminum atoms, which can act as Lewis acid sites to coordinate with the oxygen atoms in O-C=O and C-O-C in the PEO and PEO-based derivative polymer matrix, while the O-C=O and C-O-C in the PEO and PEO-based derivative polymer matrix can coordinate with Li+, and the oxygen atoms in the aluminum ethoxide can also coordinate with Li+. This double coordination mechanism greatly enhances the ordered conduction of lithium ions on the Al(EtO)3-PEO interface, improves the lithium ion conductivity, and realizes fast and ordered transmission.

[0047] (2) The nanowire filler used in the present application is not a traditional ceramic nanowire, but an amphoteric metal alkoxide. The aluminum ethoxide nanowires used in the present application are prepared by selective dealloying, and have aluminum atoms with abundant unsaturated coordination sites. These sites can effectively coordinate with PEO polymer chains, directly enhancing interfacial compatibility without the need for coupling agents. This method is different from the reported methods of other PEO-based composite electrolyte systems.

[0048] (3) The battery technology of the present application exhibits stable cycle performance in a wide temperature range of -20°C to 60°C. This feature has a significant advantage in low temperature applications, expanding the application scenarios of the battery.

[0049] (4) The aluminum ethoxide composite polymer electrolyte film prepared by the present application can match high-voltage positive electrode materials and support high-voltage commercial positive electrodes to maintain long cycle stability. This feature has important application potential in improving battery capacity and energy density, and is suitable for the development of high-energy density batteries. The aluminum ethoxide composite polymer electrolyte film prepared by the present application can be applied to all positive electrode materials of lithium / sodium batteries, such as nickel-iron-manganese sodium phosphate, sodium vanadium phosphate, etc.

[0050] (5) The Al(EtO)3-PEO system of the present application can generate an aluminum-containing-based electrolyte interface in situ on the surface of the positive and negative electrodes, which includes aluminum and its derivatives with high mechanical strength and ionic conductivity, effectively inhibiting the interface side reactions. The aluminum-containing-based electrolyte interface layer not only improves the stability of the electrode / electrolyte interface, but also prevents the phase transformation and stress cracking of high-nickel layered positive electrode materials, thereby achieving excellent cycle stability and high-rate performance. BRIEF DESCRIPTION OF DRAWINGS

[0051] Figure 1 is the cycle test graph of the battery of application example 1 and application comparative example 1;

[0052] Among them, the unfilled square and triangle are coulomb efficiency graphs;

[0053] Figure 2 is the cycle test graph of the battery of application example 2 and application comparative example 2;

[0054] Among them, the unfilled square and triangle are coulomb efficiency graphs;

[0055] Figure 3 is the cycle test graph of the battery of application example 3 and application comparative example 3;

[0056] Among them, the unfilled square and triangle are coulomb efficiency graphs;

[0057] Figure 4 is the cycle test graph of the battery of application example 4;

[0058] wherein the unfilled squares are coulombic efficiency plots;

[0059] Figure 5 for the cycling test plots of the batteries of application example 5 and application comparative example 4;

[0060] wherein the unfilled squares and triangles are coulombic efficiency plots. DETAILED DESCRIPTION

[0061] The application will be further described in conjunction with specific examples.

[0062] Example 1

[0063] A. A method for preparing an Al(EtO)3 film

[0064] (1) Weigh 0.3 g of aluminum powder and 0.085 g of lithium powder, and uniformly mix them in a graphite crucible to obtain a mixture; place the mixture in a muffle furnace, heat at 800°C for 20 min, then quickly take it out and flatten it with a graphite column, and cool to obtain a LiAl alloy.

[0065] (2) Synthesis of Al(EtO)3: react 0.115 g of LiAl alloy with 20 mL of anhydrous ethanol for 30 h to obtain a uniform Al(EtO)3 gel.

[0066] (3) Wash the gel obtained in step (2) with 10 mL of anhydrous ethanol three times to remove soluble lithium ethoxide, take 2 mL of the gel, filter to obtain a smooth Al(EtO)3 film, and cut it into small round pieces with a diameter of 16 mm.

[0067] B. A method for preparing an aluminum ethoxide composite polymer electrolyte film

[0068] S1. Under an inert atmosphere, mix PEGDA (mixed with 1 wt% of photoinitiator BAPO) and a basic lithium battery electrolyte (1 mol LiPF6 in a mixed solution of EC, DMC and EMC (volume ratio of EC: DMC: EMC is 1:1:1) at 1.5:10 (w / w), stir overnight to form a uniform solution to obtain a photocuring precursor solution.

[0069] wherein the mass ratio of PEGDA (mixed with 1 wt% of photoinitiator BAPO) to the basic electrolyte is 1.5:10.

[0070] S2. Inject 20 μL of the photocuring precursor solution onto the Al(EtO)3 film, and cure it under ultraviolet radiation for 20 s to obtain a composite polymer electrolyte (Al(EtO)3-PEGDA).

[0071] Example 2

[0072] A, Commercial ethanol aluminum powder grinding treatment:

[0073] Weigh 1 g of ethanol aluminum powder purchased from Maclin Reagent Network (item number: A831038) in a mortar and grind for half an hour.

[0074] B, A method for preparing an ethanol aluminum composite polymer electrolyte film

[0075] S1, Under an inert atmosphere, TEPTA (mixed with 1wt% of photoinitiator BAPO) and the base lithium battery electrolyte (1mol LiPF6 in a mixed solution of EC, DMC and EMC (volume ratio of EC: DMC: EMC is 1:1:1.2) and ethanol aluminum powder were mixed at 1.5:10:0.3 (w / w / w), stirred overnight to form a uniform solution, to form a photocured precursor solution.

[0076] The mass ratio of TEPTA (mixed with 1wt% of photoinitiator BAPO) to the base electrolyte is 1.5:10.

[0077] S2, 30μL of the photocured precursor solution was added dropwise to the lithium metal anode, and cured for 20s under ultraviolet radiation to obtain a composite gel polymer electrolyte (Al(EtO)3-TEPTA).

[0078] Example 3

[0079] A, A method for preparing an Al(EtO)3 film

[0080] (1) Weigh 0.3g of aluminum powder and 0.085g of lithium powder, and mix them uniformly in a graphite crucible to obtain a mixture; place the mixture in a muffle furnace and heat at 800℃ for 20min, then quickly take it out and flatten it with a graphite column, and cool it to obtain a LiAl alloy.

[0081] (2) Synthesis of Al(EtO)3: 0.115g of LiAl alloy was reacted with 20mL of anhydrous ethanol for 30h to obtain a uniform Al(EtO)3.

[0082] (3) The obtained gel was washed with 10mL of anhydrous ethanol for 3 times to remove soluble lithium alcohol, 2mL of the gel was taken out, filtered to obtain a smooth Al(EtO)3 film, and cut into small round pieces with a diameter of 16mm.

[0083] B, A method for preparing an ethanol aluminum composite polymer electrolyte film

[0084] S1, under inert atmosphere, mix TEGDA (mixed with 1wt% photoinitiator BAPO) and base lithium battery electrolyte (1mol LiPF6 in a mixed solution of EC, DMC and EMC (volume ratio of EC:DMC:EMC is 1:1:1) at 1.5:10 (w / w), stir overnight to form a uniform solution to obtain a photocured precursor solution.

[0085] wherein the mass ratio of TEGDA (mixed with 1wt% photoinitiator BAPO) to base electrolyte is 1.3:10.

[0086] S2, inject 30μL of the photocured precursor solution onto the Al(EtO)3 film, and cure for 20s under UV irradiation to obtain a composite polymer electrolyte (Al(EtO)3-TEGDA).

[0087] Example 4

[0088] A, a method for preparing an Al(EtO)3 film

[0089] (1) Weigh 0.3g of aluminum powder and 0.085g of lithium powder, and mix them uniformly in a graphite crucible to obtain a mixture; place the mixture in a muffle furnace and heat at 800°C for 20min, then quickly take it out and flatten it with a graphite column, and cool it to obtain a LiAl alloy.

[0090] (2) Synthesis of Al(EtO)3: react 0.115g of LiAl alloy with 20mL of anhydrous ethanol for 30h to obtain a uniform Al(EtO)3 gel.

[0091] (3) Wash the obtained gel with 10mL of anhydrous ethanol for 3 times to remove soluble lithium ethoxide, take 2mL of the gel, filter to obtain a smooth Al(EtO)3 film, and cut it into small round pieces with a diameter of 16mm.

[0092] B, a method for preparing an ethanol aluminum composite polymer electrolyte film

[0093] S1, under inert atmosphere, mix ε-CL with base lithium battery electrolyte (1mol LiTFSI in a mixed solution of EC, DEC (volume ratio of EC:DEC is 1:1) at 1:1 (w / w), stir overnight to form a uniform solution to obtain a photocured precursor solution.

[0094] wherein the mass ratio of ε-CL to base electrolyte is 1:1.

[0095] S2, inject 20μL of the photocured precursor solution onto the Al(EtO)3 film, and incubate in a 50°C incubator for 4h to obtain a composite polymer electrolyte (AN-PCL).

[0096] Example 5

[0097] A, Commercial ethanol aluminum powder grinding treatment:

[0098] Weighed 1 g of ethanol aluminum powder purchased from Maclin Reagent Network (item number: A831038) in a mortar and ground for half an hour.

[0099] B, A method for preparing an ethanol aluminum composite polymer electrolyte film

[0100] S1, Under an inert atmosphere, TEPTA (mixed with 1wt% photoinitiator BAPO) and the base sodium battery electrolyte (1 mol NaPF6 in a mixed solution of Diglyme and ethanol aluminum powder mixed at 1.5:10:0.3 (w / w / w), stirred overnight to form a uniform solution, to form a photocuring precursor solution.

[0101] The mass ratio of TEPTA (mixed with 1wt% photoinitiator BAPO) to the base electrolyte is 1.5:10.

[0102] S2, 30μL of the photocuring precursor solution was added dropwise to the sodium metal anode, and cured under ultraviolet radiation for 20 seconds to obtain a composite polymer electrolyte (Al(EtO)3-TEPTA-Na).

[0103] Comparative Example 1

[0104] The difference from Step A of Example 1 is that a step is added, specifically: the Al(EtO)3 film prepared in Example 1 is calcined at 800℃ for 2h to obtain an aluminum oxide film (diameter 16mm).

[0105] Step B, A method for preparing an ethanol aluminum composite polymer electrolyte film

[0106] S1, Under an inert atmosphere, PEGDA (mixed with 1wt% photoinitiator BAPO) and the base lithium battery electrolyte (1 mol LiPF6 in a mixed solution of EC, DMC and EMC (volume ratio of EC: DMC: EMC is 1:1:1)) were mixed at 1.5:10 (w / w), stirred overnight to form a uniform solution, to form a photocuring precursor solution.

[0107] S2, 20μL of the photocuring precursor solution was injected onto the aluminum oxide film, and cured under ultraviolet radiation for 20s to obtain a composite polymer electrolyte (Al2O3-PEGDA).

[0108] Comparative Example 2

[0109] Step B, A method for preparing an ethanol aluminum composite polymer electrolyte film

[0110] S1, TEPTA mixed with 1wt% photoinitiator BAPO and base lithium battery electrolyte (1 mol LiPF6in a mixed solution of EC, DMC and EMC (volume ratio of EC: DMC: EMC is 1:1:1) were mixed at 1.5:10 (w / w) under inert atmosphere, stirred overnight to form a uniform solution, to obtain a photocured precursor solution.

[0111] The mass ratio of TEPTA (mixed with 1wt% photoinitiator BAPO) to base electrolyte is 1.3:10.

[0112] S2, 30μL of the photocured precursor solution was dropped onto the lithium metal negative electrode, and cured for 20s under ultraviolet radiation to obtain a polymer electrolyte (GPE-TEPTA).

[0113] Comparative Example 3

[0114] Step B, a preparation method of an aluminum ethoxide composite polymer electrolyte film

[0115] S1, TEGDA mixed with 1wt% photoinitiator BAPO and base lithium battery electrolyte (1 mol LiPF6in a mixed solution of EC, DMC and EMC (volume ratio of EC: DMC: EMC is 1:1:1) were mixed at 1.5:10 (w / w) under inert atmosphere, stirred overnight to form a uniform solution, to obtain a photocured precursor solution.

[0116] The mass ratio of TEGDA (mixed with 1wt% photoinitiator BAPO) to base electrolyte is 1.3:10.

[0117] S2, 30μL of the photocured precursor solution was dropped onto the lithium metal negative electrode, and cured for 20s under ultraviolet radiation to obtain a polymer electrolyte (GPE-TEGDA).

[0118] Comparative Example 4

[0119] Step B, a preparation method of an aluminum ethoxide composite polymer electrolyte film

[0120] S1, TEPTA mixed with 1wt% photoinitiator BAPO and base sodium battery electrolyte (1 mol NaPF6in a mixed solution of Diglyme) were mixed at 1.5:10 (w / w) under inert atmosphere, stirred overnight to form a uniform solution.

[0121] The mass ratio of TEPTA (mixed with 1wt% photoinitiator BAPO) to base electrolyte is 1.5:10.

[0122] S2, 30 μL of the photocured precursor was added to the sodium metal negative electrode, and cured for 20 seconds under UV irradiation to obtain a polymer electrolyte (GPE-TEPTA-Na).

[0123] Application Examples

[0124] The ethanol aluminum composite polymer electrolyte membranes prepared in Examples 1-5 and Comparative Examples 1-4 were used to assemble batteries, obtaining Application Examples 1-5 and Application Comparative Examples 1-4.

[0125] Method for assembling a battery:

[0126] (1) combining the prepared ethanol aluminum composite polymer electrolyte membrane with a metal negative electrode;

[0127] (2) using a commercial positive electrode as the positive electrode material;

[0128] (3) assembling to obtain a full battery.

[0129] Among them, the positive electrode of Examples 1-3 and Comparative Example 1-3 uses a commercial NCM622, the positive electrode of Example 4 uses a commercial LFP, and the positive electrode of Examples 5 and Comparative Example 4 uses a commercial NVP.

[0130] The preparation method of LiFePO4(LFP) positive electrode sheet is as follows:

[0131] (1) Mixing: LFP powder, acetylene black powder, and PVDF powder were weighed according to a ratio of 7:2:1 in a mortar, and manually ground for 30 min to mix the three powders uniformly. The powders were then transferred to a glass bottle with a magnet, and N-methyl pyrrolidone (NMP) was added for high-speed stirring for 4 h to form a slurry;

[0132] (2) Coating: After the slurry was uniformly stirred, it was coated on a coating machine. The positive electrode current collector used a flat aluminum foil, and a doctor blade was used during the coating process to ensure the uniform thickness and quality of the electrode sheet. Finally, the coated electrode sheet was placed in a vacuum drying oven at 80°C for 24 h to remove the solvent. The dried electrode sheet was cut into 10 mm round pieces, and the active material loading was about 2 mg cm -2 .

[0133] The preparation method of NCM622 positive electrode sheet is as follows:

[0134] (1) Mixing: NCM622 powder, acetylene black powder, and PVDF powder were weighed according to a ratio of 8:1:1 in a mortar, and manually ground for 30 min to mix the three powders uniformly. The powders were then transferred to a glass bottle with a magnet, and N-methyl pyrrolidone (NMP) was added for high-speed stirring for 4 h to form a slurry;

[0135] (2) Coating: After the slurry is stirred evenly, it can be coated on the coating machine. The positive current collector uses flat aluminum foil. A doctor blade is used during the coating process to ensure that the thickness and quality of the electrode sheet are uniform. Finally, the coated electrode sheet is placed in a vacuum drying oven at 80°C for 24h to remove the solvent. The dried electrode sheet is cut into 10mm discs, and the active material loading is about 2mg cm -2 .

[0136] The method for preparing the Na3V2(PO4)3(NVP) positive electrode sheet is as follows:

[0137] (1) Mixing: NVP powder, acetylene black powder, and PVDF powder are weighed according to a ratio of 7:2:1 in a mortar, and manually ground for thirty minutes to mix the three powders evenly. The powders are then transferred to a glass bottle with a magnet, and N-methyl pyrrolidone (NMP) is added for high-speed stirring for four hours to form a slurry.

[0138] (2) Coating: After the slurry is stirred evenly, it can be coated on the coating machine. The positive current collector uses flat aluminum foil. A doctor blade is used during the coating process to ensure that the thickness and quality of the electrode sheet are uniform. Finally, the coated electrode sheet is placed in a vacuum drying oven at 80°C for 24h to remove the solvent. The dried electrode sheet is cut into 10mm discs, and the active material loading is about 2mg cm -2 .

[0139] The method for assembling the battery is as follows: The battery shell (model CR2032) is composed of a negative shell, a positive shell, a spring, and a gasket. From bottom to top, they are the positive shell, the positive material, the ethanol aluminum composite polymer electrolyte, the negative material, the stainless steel gasket, the spring, and the negative shell. Finally, the battery is moved to the sealing machine using an insulating tweezer to seal the battery.

[0140] Effect experiment

[0141] The stability of the assembled battery is tested:

[0142] Experimental method

[0143] Battery constant current charge and discharge test: The LAND CT2001A battery test system is used to apply a specific current to the assembled button cell, and the voltage change with time is monitored and recorded. The capacity, long cycle stability, rate, and coulombic efficiency of the battery can be obtained. The batteries of the application examples and the application comparative examples are tested at 30°C.

[0144] Analysis of experimental results

[0145] As can be seen from Figure 1 , Example 1 uses the Li|Al(EtO)3-PEGDA|NCM622 battery for cycle test, and the capacity is 127mAh g after 150 cycles-1 The capacity retention rate was 89%.

[0146] As can be seen from Figure 2 Example 2, the Li|Al(EtO)3-TEPTA|NCM622 battery was subjected to cycle test, and the capacity was 158 mAh g -1 after 100 cycles, with a capacity retention rate of 80%.

[0147] As can be seen from Figure 3 Example 3, the Li|Al(EtO)3-TEGDA|NCM622 battery was subjected to cycle test, and the capacity was 122 mAh g -1 after 90 cycles, with a capacity retention rate of 98%.

[0148] As can be seen from Figure 4 Example 4, the Li|AN-PCL|LFP battery was subjected to cycle test, and the capacity was 98 mAh g -1 after 75 cycles.

[0149] As can be seen from Figure 5 Example 5, the Na|Al(EtO)3-TEPTA-Na|NVP battery was subjected to cycle test, and the capacity retention rate was as high as 92% after 500 high-rate 25C cycles.

[0150] Comparative Example 1 used a Li|Al2O3-PEGDA|NCM622 battery for cycle test, and the battery failed to normally charge and discharge after 3 cycles. Figure 1

[0151] Comparative Example 2 used a Li|GPE-TEPTA|NCM622 battery for cycle test, and the capacity decayed to 61 mAh g -1 after 100 cycles, with a capacity retention rate of only 69%. Figure 2

[0152] Comparative Example 3 used a Li|GPE-TEGDA|NCM622 battery for cycle test, and the capacity decayed to 119 mAh g -1 after 90 cycles, with a capacity retention rate of only 92%. Figure 3

[0153] Comparative Example 4 used a Na|GPE-TEPTA-Na|NVP battery for cycle test, and the battery failed to normally charge and discharge after 355 cycles. Figure 5

[0154] ​​​​From the above, according to application examples 2-4, compared with the simple composite polymer electrolyte membrane, the composite polymer needs to be combined with aluminum ethoxide to obtain an electrolyte membrane, so that the cycle stability of the battery is better; according to application example 1, the electrolyte membrane obtained by combining aluminum ethoxide with the composite polymer has better cycle stability than the electrolyte membrane obtained by combining Al2O3 with the composite polymer.

[0155] The above examples are only used to illustrate the technical solutions of the present application, but not limit the present application; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that the technical solutions recorded in the foregoing examples can be modified, or some technical features can be replaced by equivalent features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. An ethanol aluminum composite polymer electrolyte membrane, characterized by, The ethanol aluminum composite polymer electrolyte film comprises a polymer and ethanol aluminum; The polymer is a polymer containing an ester group or / and an ether bond in the structure; the polymer is a polyethylene oxide or a polyethylene oxide derivative; the polyethylene oxide derivative is obtained by photopolymerization of small molecule monomers; The preparation method of the ethanol aluminum composite polymer electrolyte film comprises the following steps: A. Synthesis of ethanol aluminum film (1) Aluminum powder is mixed with metal powder to obtain an alloy sheet in a molten state; (2) The alloy sheet in step (1) is cooled and then reacted with anhydrous ethanol to obtain an ethanol aluminum gel; (3) The by-product is washed and the ethanol aluminum gel obtained in step (2) is filtered to obtain an ethanol aluminum film; B. Synthesis of ethanol aluminum composite polymer electrolyte film S1. Under an inert atmosphere, polymer monomers and a photoinitiator are mixed to obtain a mixed solution, and then the mixed solution and a base electrolyte or an electrolyte salt are mixed and stirred to obtain a light-cured precursor solution; S2. The ethanol aluminum film obtained in step A is placed on a negative electrode, the light-cured precursor solution obtained in S1 is added dropwise, and ultraviolet light irradiation or drying is performed, thereby obtaining the ethanol aluminum composite polymer electrolyte film.

2. The ethanol aluminum composite polymer electrolyte membrane according to claim 1, characterized by The small molecule monomers are selected from one or more of polyethylene glycol diacrylate, triethylene glycol diacrylate, polytetraethylene glycol diacrylate, tetraglycol diacrylate, 1,3-dioxolane, polyethylene glycol dimethyl ether, ε-caprolactone, and ethoxylated trimethylolpropane triacrylate.

3. The ethanol aluminum composite polymer electrolyte membrane according to claim 1, characterized by, The mass fraction of the photoinitiator in the monomers in S1 of step B is 1-10 wt%.

4. The ethanol aluminum composite polymer electrolyte membrane according to claim 1, characterized by, The base electrolyte in S1 of step B comprises an electrolyte salt and a solvent; the weight ratio of the mixed solution to the base electrolyte is 1-10:

10.

5. Use of the ethanol aluminum composite polymer electrolyte film according to any one of claims 1-4 in the preparation of a battery.

6. A battery, characterized by The battery comprises the ethanol aluminum composite polymer electrolyte film according to any one of claims 1-4.

7. The battery of claim 6, wherein, The battery is a lithium battery or a sodium battery.

8. The battery of claim 6, wherein, The battery comprises a negative electrode, an ethanol aluminum composite polymer electrolyte film, and a positive electrode.

9. The process for assembling a battery according to any one of claims 6 to 8, characterized in that, The battery comprises the following steps: (1) combining the prepared ethanol aluminum composite polymer electrolyte film with a negative electrode; (2) using a commercial positive electrode as a positive electrode material; (3) assembling to obtain a battery.

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