阅读说明：本技术 一种功能化金属-有机框架材料及其制备方法和应用 (Functionalized metal-organic framework material and preparation method and application thereof ) 是由 肖迎波 李琦 张琪 黄少铭 于 2020-11-18 设计创作，主要内容包括：本发明公开了一种功能化金属-有机框架材料及其制备方法和应用,本发明利用含巯基的有机配体和金属盐在较低的反应温度下先制得金属-有机框架材料,然后经过氧化处理,制得功能化金属-有机框架材料,所制得的功能化金属-有机框架材料结晶性好,结构均匀,尺寸较小,可用于制备固态电解质膜。将所制得的固态电解质膜用于组装固态锂金属电池,所获得的固态锂金属电池循环性能稳定,倍率性能好。(The invention discloses a functionalized metal-organic framework material and a preparation method and application thereof. The prepared solid electrolyte membrane is used for assembling a solid lithium metal battery, and the obtained solid lithium metal battery has stable cycle performance and good rate capability.)

1. A preparation method of a functionalized metal-organic framework material is characterized by comprising the following steps:

s1, dissolving a sulfydryl-containing organic ligand and metal salt in a solvent, reacting for 10-60 min at 100-150 ℃, washing, and drying to obtain a metal-organic framework material; the metal salt is a zirconium salt; wherein the molar ratio of the mercapto-containing organic ligand to the metal salt is 2-8: 1;

s2, oxidizing the metal-organic framework material prepared in the step S1 to prepare a functionalized metal-organic framework material.

2. The method according to claim 1, wherein the thiol-group-containing organic ligand in step S1 is one or more selected from mercaptosuccinic acid, 2, 5-dimercaptoterephthalic acid, 2, 5-bis (2- (methylthio) ethylthiol) terephthalic acid, tetramethylterephthalic acid, and benzylmercaptan.

3. The method according to claim 1 or 2, wherein the reaction temperature in step S1 is 110-140 ℃.

4. The method according to claim 1, wherein the molar ratio of the thiol-group-containing organic ligand to the metal salt in step S1 is 3-7: 1.

5. the functionalized metal-organic framework material prepared by the preparation method of any one of claims 1 to 4.

6. A solid electrolyte membrane made from the functionalized metal-organic framework material of claim 5.

7. The method for producing a solid electrolyte membrane according to claim 6, comprising the steps of:

dissolving a functionalized metal-organic framework material, poly (vinylidene fluoride-co-hexafluoropropylene), cellulose powder and metal salt in a solvent, uniformly mixing, coating on a mold, drying at 60-100 ℃, then immersing in a salt solution, taking out after 12-24 h, and drying to obtain the solid electrolyte membrane.

8. The preparation method according to claim 7, wherein the metal salt is one or more of lithium bis (trifluoromethyl) sulfonyl imide, lithium bis (fluoro) sulfonyl imide, lithium perchlorate, lithium chloride, lithium oxalate, lithium bromide and lithium hexafluorophosphate.

9. Use of the solid electrolyte membrane according to claim 6 for assembling a solid lithium metal battery.

10. The application of the lithium iron phosphate battery as claimed in claim 9, wherein lithium is used as a cathode material and lithium is used as an anode material, and the lithium iron phosphate battery and the solid electrolyte membrane are assembled into a button type solid lithium metal battery.

Technical Field

The invention relates to the technical field of solid electrolyte materials, in particular to a functionalized metal-organic framework material and a preparation method and application thereof.

Background

Energy storage devices are a key technology in modern human society. The lithium ion secondary battery has the advantages of high working voltage, long cycle life, small environmental pollution and the like, is widely applied to various portable digital products and becomes a green chemical power supply with very common application. However, at present, the energy density (<200Wh/kg) is still difficult to meet the use requirements of electric automobiles and the like. The new generation of high specific energy lithium battery is the development direction of future energy storage devices, and the development depends on the development of high capacity electrode materials and the solution of the safety problem of the battery. Lithium metal (Li) has a high theoretical specific capacity (3860mAh/g), low density and extremely low electrode potential, and is therefore considered an ideal battery negative electrode material. The metallic lithium negative electrode also eliminates the use of a current collector, and thus can significantly improve the energy density of the battery. Unfortunately, lithium metal negative electrodes are prone to safety problems caused by lithium dendrite growth due to non-uniform deposition in cyclic charge and discharge, application of lithium metal electrodes is hindered, and high-energy-density lithium batteries are prone to leakage, ignition, explosion and other potential safety hazards due to the use of organic electrolytes. One of the effective ways to improve the safety of the battery is to use a solid polymer electrolyte instead of a conventional organic electrolyte. For example, chinese patent CN103779597A discloses a solid electrolyte polymer membrane, which is prepared by performing a hydrothermal reaction on a precursor composition of graphene oxide and a metal organic framework at 180 ℃ to prepare a coexisting body, and then immersing the coexisting body in an organic solution of sulfochlorinated polyphenylene oxide to graft sulfonated polyphenylene oxide.

Disclosure of Invention

The invention aims to solve the technical problems of high reaction temperature, uneven structure and large size of the prepared solid electrolyte membrane in the existing method for preparing the solid electrolyte membrane, and provides a method for preparing a functionalized metal-organic framework material, which has low reaction temperature, uniform structure and small size of the prepared solid electrolyte membrane, and when the functionalized metal-organic framework material is used as a battery material, the rate capability and the cycling stability of the prepared battery are good.

It is yet another object of the present invention to provide a functionalized metal-organic framework material.

It is another object of the present invention to provide a use of the functionalized metal-organic framework material.

The above purpose of the invention is realized by the following technical scheme:

a preparation method of a functionalized metal-organic framework material comprises the following steps:

s1, dissolving a sulfydryl-containing organic ligand and metal salt in a solvent, reacting for 10-60 min at 100-150 ℃, washing, and drying to obtain a metal-organic framework material; the metal salt is a zirconium salt; wherein the molar ratio of the mercapto-containing organic ligand to the metal salt is 2-8: 1;

s2, oxidizing the metal-organic framework material prepared in the step S1 to prepare a functionalized metal-organic framework material.

The invention utilizes organic ligand containing sulfhydryl and metal salt to prepare metal-organic framework material (Zr-MOF-SH) at lower reaction temperature, and then prepares functional metal-organic framework material (Zr-MOF-SO) after oxidation treatment₃H) In that respect The preparation method can complete the reaction at a lower temperature, the reaction condition is mild, and the prepared functionalized metal-organic framework material has good crystallinity, uniform structure and small size; after oxidation treatment, under the premise of keeping the structure and the size, the sulfydryl on the Zr-MOF-SH can be oxidized into sulfonic group with stronger ion conducting capacity by adopting one-step reaction to obtain the functional metal-organic framework material Zr-MOF-SO₃H, small and uniform size Zr-MOF-SO for the preparation of solid electrolyte membranes₃H can optimize the conduction performance of metal ions between crystal interfaces, the interface impedance is small, and the ion conduction efficiency is high; the sulfonic acid group with strong ion conducting capability is beneficial to the migration of lithium ions, and inhibits the conduction of anions. The prepared solid electrolyte membrane can be better used for assembling a solid lithium metal battery, and the polarization inside the battery in the obtained solid lithium metal battery is reduced, the side reaction is less, the cycle performance is stable, and the rate capability is good.

Preferably, the mercapto-containing organic ligand is one or more of mercaptosuccinic acid, 2, 5-dimercaptoterephthalic acid, 2, 5-bis (2- (methylthio) ethylmercapto) terephthalic acid, tetramethylmercaptoterephthalic acid and benzylmercaptan.

More preferably, the thiol-group-containing organic ligand in step S1 is one or more of mercaptosuccinic acid, 2, 5-dimercaptoterephthalic acid and 2, 5-bis (2- (methylthio) ethylthiol) terephthalic acid.

Preferably, the reaction temperature in the step S1 is 110-140 ℃.

Preferably, the molar ratio of the mercapto-containing organic ligand to the metal salt in step S1 is 3-7: 1.

preferably, the oxidation treatment in the step S2 is hydrogen peroxide treatment for 1 to 3 hours.

The invention protects the functionalized metal-organic framework material prepared by the preparation method.

A solid electrolyte membrane is prepared by the functionalized metal-organic framework material.

The invention protects the preparation method of the solid electrolyte membrane, which comprises the following steps:

dissolving a functionalized metal-organic framework material, poly (vinylidene fluoride-co-hexafluoropropylene), cellulose powder and metal salt in a solvent, uniformly mixing, coating on a mold, drying at 60-100 ℃, then immersing in a salt solution, taking out after 12-24 h, and drying to obtain the solid electrolyte membrane.

Preferably, the metal salt is one or more of bis (trifluoromethyl) sulfonyl imide lithium, bis (fluoro) sulfonyl imide lithium, lithium perchlorate, lithium chloride, lithium oxalate, lithium bromide and lithium hexafluorophosphate.

The invention protects the application of the solid electrolyte membrane in assembling the solid lithium metal battery.

Specifically, lithium iron phosphate is used as a positive electrode material, lithium is used as a negative electrode material, and the lithium iron phosphate and a solid electrolyte membrane are assembled into a button type solid lithium metal battery.

Compared with the prior art, the invention has the beneficial effects that:

the invention utilizes the organic ligand containing sulfhydryl and metal salt to prepare firstly at lower reaction temperatureObtaining a metal-organic framework material (Zr-MOF-SH), and then preparing the functional metal-organic framework material (Zr-MOF-SO) after oxidation treatment₃H) In that respect The preparation method disclosed by the invention is low in reaction temperature and milder in conditions, the prepared functionalized metal-organic framework material is good in crystallinity, uniform in structure, small in size and good in ion conduction capability, can be used for preparing a solid electrolyte membrane, can optimize the conduction performance of metal ions between crystal interfaces, is small in interface impedance and high in ion conduction efficiency, is beneficial to migration of lithium ions and inhibition of conduction of anions, and further the prepared solid electrolyte membrane is used for a solid lithium metal battery, so that the inside of the battery in the obtained solid lithium metal battery is stable in cycle performance and good in rate performance.

Drawings

FIG. 1 is an infrared spectrum of a functionalized metal-organic framework material prepared in example 1 of the present invention.

FIG. 2 is an X-ray diffraction pattern of the functionalized metal-organic framework material prepared in example 1 of the present invention.

FIG. 3 is a scanning electron microscope image of the functionalized metal-organic framework material prepared in example 1 of the present invention.

FIG. 4 is a scanning electron microscope image of the metal-organic framework material prepared in comparative example 1 of the present invention.

FIG. 5 is a diagram of Zr-MOF-SO prepared in example 1 of the present invention₃H and MIL-101-SO prepared in comparative example 1₃H rate performance plot for solid state lithium metal batteries.

FIG. 6 shows Zr-MOF-SO prepared in example 1 of the present invention₃H and MIL-101-SO prepared in comparative example 1₃H cycle performance diagram for assembling solid state lithium metal batteries.

Detailed Description

The present invention will be further described with reference to specific embodiments, but the present invention is not limited to the examples in any way. The starting reagents employed in the examples of the present invention are, unless otherwise specified, those that are conventionally purchased.

Example 1

A preparation method of a functionalized metal-organic framework material comprises the following steps:

s1, weighing 0.75g of zirconium chloride and 2.4g of mercaptosuccinic acid, uniformly stirring in 3mL of deionized water, placing the solution in a 25mL round-bottom flask, thermally refluxing by adopting a solvent, keeping the temperature at 138 ℃ for 15min, washing by using absolute ethyl alcohol after the reaction is cooled, centrifuging, and drying in vacuum to obtain a metal-organic framework material Zr-MOF-SH;

s2, mixing and stirring 0.2g of Zr-MOF-SH and 30mL of hydrogen peroxide with the mass fraction of 30% for 2h, repeatedly washing with deionized water and ethanol, placing in a vacuum drying oven at 80 ℃, and drying for 4h to obtain Zr-MOF-SO₃H。

Example 2

The functionalized metal-organic framework material of this comparative example was prepared in the same manner as in example 1, except that the reaction temperature of step S1 was replaced with 110 ℃, and mercaptosuccinic acid was replaced with 2, 5-dimercaptoterephthalic acid.

Example 3

The functionalized metal-organic framework material of this comparative example was prepared in the same manner as in example 1, except that the reaction temperature of step S1 was replaced with 120 ℃, and mercaptosuccinic acid was replaced with 2, 5-bis (2- (methylthio) ethylmercapto) terephthalic acid.

Example 4

The functionalized metal-organic framework material of this comparative example was prepared in the same manner as in example 1, except that the reaction temperature of step S1 was replaced with 130 ℃.

Comparative example 1

The comparative example adopts a hydrothermal method to prepare the functionalized metal-organic framework material, and comprises the following steps:

weighing 0.2g of zirconium nitrate nonahydrate and 0.268g of 2-sulfoterephthalic acid monosodium salt, uniformly stirring in 3mL of deionized water, placing the solution in a 25mL reaction kettle, keeping the temperature at 190 ℃ for 24h, washing with absolute ethyl alcohol after the reaction is cooled, centrifuging, and drying in vacuum to obtain the metal-organic framework material MIL-101-SO₃H。

Comparative example 2

The comparative example adopts a hydrothermal method to prepare the functionalized metal-organic framework material, and comprises the following steps:

weighing 0.1g of zirconyl chloride octahydrate and 0.083g of monosodium 2-sulfophthalate in 3mL of DMF solution, uniformly stirring, placing the solution in a 25mL reaction kettle, keeping the temperature at 150 ℃ for 24h, washing with absolute ethyl alcohol after reaction and cooling, centrifuging, and drying in vacuum to obtain the metal-organic framework material UIO-66-SO₃H。

Comparative example 3

The comparative example adopts a hydrothermal method to prepare the functionalized metal-organic framework material, and comprises the following steps:

0.34g of copper nitrate trihydrate and 0.22g of disodium 1, 2-ethanedisulfonate are weighed and uniformly stirred in 10mL of deionized water solution, the solution is placed in a 25mL reaction kettle, the temperature is kept at 175 ℃ for 72 hours, after reaction cooling, absolute ethyl alcohol is used for washing and centrifuging, and vacuum drying is carried out to obtain the metal-organic framework material TMOF-SO₃H。

Applications of

1. Preparation of solid electrolyte membranes based on metal-organic framework materials

0.35g of the metal-organic framework material prepared in each of the above examples and comparative examples, 0.1g of poly (vinylidene fluoride-co-hexafluoropropylene), 0.05g of cellulose powder, and 0.574g of lithium bistrifluoromethylsulfonimide were weighed and mixed with 2mL of N, N-dimethylformamide, and stirred for 12 hours to obtain a uniform mixed slurry; coating the mixed slurry in a polytetrafluoroethylene die, then placing the polytetrafluoroethylene die in a baking oven at 80 ℃ for drying for 12 hours, and removing residual organic solvent; tearing the film from the mold by using tweezers, repeatedly washing the film by using deionized water and ethanol to remove unreacted organic matters, then placing the film in a vacuum drying oven at 80 ℃, drying the film for 4 hours, and removing residual organic solvent and water to obtain a flexible solid film; and soaking the flexible solid film in a propylene carbonate solution (1mol/L) of lithium bis (trifluoromethyl) sulfimide, taking out after 12 hours, and wiping to dry to obtain the solid electrolyte film.

2. Use of solid electrolyte membranes based on metal-organic framework materials in lithium metal batteries

The prepared solid electrolyte membrane is assembled into a solid lithium metal battery taking lithium iron phosphate as a positive electrode and lithium metal as a negative electrode.

Performance testing

1. Test method

(1) Zr-MOF-SO prepared in example 1₃H and MIL-101-SO prepared in comparative example 1₃And H, using an SU 8010-Hitachi novel high-resolution field emission scanning electron microscope to perform micro-morphology testing.

(2) Zr-MOF-SO prepared in example 1₃H, X-ray diffraction tests were carried out using Rigaku Smartlab 9kW, science.

(3) Zr-MOF-SO prepared in example 1₃H, infrared spectroscopy was performed using a BAM7-Spectrum 65 Fourier transform infrared spectrometer.

(4) And respectively carrying out rate performance test and cycle performance test on the solid lithium metal battery in the application in a Xinwei test cabinet. The rate performance test was performed by charging and discharging at rates of 0.2C, 0.5C, 1C, 2C, and 1C (1C ═ 170mAh/g) in this order. The cycle performance test was performed by constant current charging and discharging at 1C rate (1C 170 mAh/g).

2. Test results

As can be seen from the infrared spectrum of FIG. 1, the functionalized metal-organic framework material in example 1 shows obvious sulfonic infrared stretching vibration peak, which proves that Zr-MOF-SO₃H is successfully prepared. The functionalized metal-organic framework materials obtained in examples 2 to 4 were able to detect the peak of infrared stretching vibration of the sulfonic acid group.

As can be observed from the X-ray diffraction pattern of FIG. 2, Zr-MOF-SO obtained in example 1₃H has good crystallinity, and is beneficial to the conduction of metal ions in the crystal. The metal-organic framework materials synthesized in examples 2-4 all showed good crystallinity.

As seen from the SEM photograph of FIG. 3, Zr-MOF-SO obtained in example 1₃The H structure is uniform, the size is small, the conduction of metal ions between crystal interfaces is optimized, and the interface impedance is reduced.

As seen from the SEM photograph of FIG. 4, MIL-101-SO obtained in comparative example 1₃H, large and irregular in size, is not conducive to conduction of metal ions between crystal interfaces.

The data in fig. 5 show that when the metal-organic framework material of example 1 is applied to a solid lithium metal battery, the specific discharge capacity of the battery can reach 165mAh/g, 157mAh/g, 150mAh/g, 135mAh/g and 150mAh/g at 0.2C, 0.5C, 1C and 2C, and when the battery returns to 1C for charging and discharging, the capacity of the lithium sulfur battery is high, and the capacity of the battery returned to 1C is the same as the initial capacity at 1C, which shows excellent rate capability, and both the capacity and the rate capability are significantly better than those of the solid lithium metal battery based on the metal-organic framework material of comparative example 1.

From the data in fig. 6, it can be found that the solid-state lithium metal battery based on the functionalized metal-organic framework material of example 1 can reach 138mAh/g after 500 cycles of charge and discharge at the rate of 1C, and the single-cycle decay rate is only 0.016% after cycle at the high rate of 1C, thus proving that the assembled battery has good cycle stability, and the cycle stability is obviously better than that of the solid-state lithium metal battery based on the metal-organic framework material of comparative example 1.

The functionalized metal-organic framework materials prepared in the embodiments 2 to 4 have small size, uniform structure and good crystallinity, and the test result is equivalent to the experiment result of the embodiment 1.

The metal-organic framework material prepared by the hydrothermal reaction in the comparative examples 1-3 has high reaction temperature and difficult control of the reaction, and the obtained metal-organic framework material has large and irregular size and is not beneficial to the conduction of metal ions between crystal interfaces. The test result is equivalent to that of the experiment result of the comparative example 1 and is far lower than that of the solid lithium metal battery based on the functionalized metal-organic framework materials in the examples 1-4.

It should be understood that the above-described embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.