Phosphonic acid-based metal organic framework solid electrolyte as well as preparation method and application thereof

Abstract

The invention discloses a phosphonic acid-based metal organic framework solid electrolyte as well as a preparation method and application thereof, and belongs to the technical field of solid electrolyte materials. The method comprises the following steps: mixing a metal salt, an organic phosphonic acid ligand and an organic solvent, carrying out a coordination reaction, and treating to obtain MOF powder; heating and activating the MOF powder to obtain activated MOF powder; the method comprises the following steps: mechanically grinding lithium salt and MOF powder to form a mixture, heating to enable the molten lithium salt to permeate and fill MOF channels, and cooling to obtain solid electrolyte powder. The ionic conductivity of the solid electrolyte at 30 DEG C reaches 1.01 * 10 <-4 > S cm <-1 >, and the solid electrolyte is kept stable in a 4.4 V high-voltage window. The symmetrical battery based on the phosphonic acid-based MOF solid electrolyte can stably operate, and shows excellent compatibility and stability of the electrolyte and a lithium metal negative electrode. The method has the advantages of simple operation, cheap and easily available components, and is expected to be suitable for large-scale preparation.

Description

Technical Field

[0001] The present invention belongs to the technical field of solid electrolyte materials, and in particular relates to a phosphonate-based metal organic framework solid electrolyte, a preparation method thereof, and an application thereof in a solid-state lithium battery. Background Art

[0002] With the development of energy storage technology, all-solid-state lithium batteries are considered one of the key technologies for future energy storage due to their high safety and long cycle life. Although traditional liquid electrolytes have high ion transport capabilities, they are flammable, volatile, and have unstable electrode interfaces, which seriously limit the long-term stability of lithium metal batteries.

[0003] Although inorganic solid electrolytes (such as LLZO and LATP) have high ionic conductivity and chemical stability, they are difficult to achieve a good match with electrodes due to their strong mechanical rigidity and high interfacial contact resistance. At the same time, their complex preparation process and high-temperature sintering process increase manufacturing costs.

[0004] While polymer solid electrolytes (such as PEO and PVDF) exhibit excellent interfacial compatibility, they suffer from low ionic conductivity at room temperature and limited electrochemical stability, making them difficult to adapt to high-voltage cathode materials. Furthermore, polymer-based electrolytes can experience structural aging and decreased mechanical stability during long-term cycling.

[0005] MOF-based solid electrolytes exhibit unique advantages in ion transport and interface engineering due to their high porosity, tunable pore environment, and abundant functionalized sites. However, most MOF-based solid electrolytes rely on liquid additives (such as organic solvents and ionic liquids) to enhance ionic conductivity, which not only reduces the solid-state properties of the material but also may trigger interfacial side reactions, affecting battery life.

[0006] The information disclosed in this background technology section is only intended to enhance understanding of the overall background of the invention and should not be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the Invention

[0007] In order to solve the problems of solvent volatilization, interface instability, increased anion migration and long-term battery cycle attenuation caused by the fact that MOF-based solid electrolytes mainly rely on liquid additives (such as organic solvents and ionic liquids) to improve ionic conductivity, a phosphonic acid-based metal-organic framework solid electrolyte, a preparation method thereof and its application in solid-state lithium batteries are provided.

[0008] In order to solve the above problems, the first aspect of the present invention provides a method for preparing a phosphonic acid-based metal organic framework solid electrolyte, which specifically comprises the following steps:

[0009] (1) After mixing a metal salt, an organic phosphonic acid ligand, and an organic solvent, a coordination reaction is carried out, and after the reaction is completed, MOF powder is obtained through post-treatment;

[0010] (2) heating and activating the MOF powder to remove the organic solvent in the MOF pores to obtain activated MOF powder;

[0011] (3) mechanically grinding the lithium salt and the activated MOF powder to form a mixture;

[0012] (4) The mixture of step (3) is heated to allow the molten lithium salt to penetrate and fill the MOF pores, and then cooled to obtain a solid electrolyte powder.

[0013] In some embodiments, in step (1), the metal salt is one or more of a zirconium salt, a zinc salt, a cobalt salt, a magnesium salt, and a manganese salt; preferably, the metal salt is one or more of zirconium chloride, zinc chloride, cobalt chloride, magnesium chloride, and manganese chloride;

[0014] And / or, the organic phosphonic acid ligand is one or more of aminotrimethylenephosphonic acid (ATMP), hydroxyethylidene diphosphonic acid, ethylenediamine tetramethylenephosphonic acid, and diethylenetriamine penta (methylenephosphonic acid);

[0015] And / or, the molar ratio of the metal salt to the organic phosphonic acid ligand is 1:0.8 to 1:1.2.

[0016] In some embodiments, in step (1), the post-treatment includes filtering, washing, drying, and grinding into powder to obtain the MOF powder;

[0017] And / or, the solvent is DMF; the coordination reaction temperature is 120-150° C.; and the coordination reaction time is 12-15 hours.

[0018] In some embodiments, in step (2), the activation method includes: heating the MOF powder in a vacuum environment to remove the solvent in the MOF pores; vacuum environment activation is more conducive to removing residual solvent in the MOF.

[0019] Preferably, the heating temperature is 150-180° C., and the heating time is 12-24 hours.

[0020] In some embodiments, in step (3), the lithium salt is one or more of lithium perchlorate, lithium nitrate, lithium tetrafluoroborate, lithium hexafluorophosphate, lithium bis(oxalatoborate), lithium difluorooxalatoborate, lithium bis(difluorosulfonylimide), and lithium bis(trifluoromethylsulfonylimide); preferably, the lithium salt is lithium bis(trifluoromethylsulfonylimide);

[0021] And / or, the content of lithium salt loaded in the MOF is 20 wt% to 60 wt%, that is, the mass of the lithium salt accounts for the percentage of the total mass of the MOF and the lithium salt;

[0022] And / or, the mass ratio of the lithium salt to the MOF powder in step (3) is 0.25:1 to 1.5:1.

[0023] In some embodiments, in step (4), the heating temperature is 250-260° C. and the heating time is 15-30 minutes.

[0024] In some embodiments, the method further comprises: pressing the solid electrolyte powder into tablets to obtain a phosphonic acid-based MOF all-solid electrolyte;

[0025] The tabletting pressure is 3 to 5T and the tabletting time is 5 to 10 minutes.

[0026] A second aspect of the present invention provides a phosphonic acid-based MOF all-solid-state electrolyte prepared by the above method.

[0027] A third aspect of the present invention provides a solid-state electrode comprising the above-mentioned phosphonic acid-based MOF all-solid-state electrolyte.

[0028] A fourth aspect of the present invention provides a use of the above-mentioned phosphonic acid-based MOF all-solid-state electrolyte in a solid-state lithium battery.

[0029] Beneficial effects: Compared with the existing technology, the advantages of the present invention include:

[0030] (1) In the metal-organic framework (MOF) matrix, the oxygen atoms of the phosphonate group of the ligand molecule can act as effective coordination sites to interact with lithium ions due to the presence of lone pairs of electrons. Lithium ions, as central ions, can form coordination bonds with the oxygen atoms of multiple phosphonate groups in the MOF matrix, thereby constructing a continuous lithium ion transmission pathway. This unique coordination structure not only provides a stable transmission path for lithium ions, but also significantly reduces the transmission energy barrier of lithium ions, accelerating their diffusion in the MOF matrix. Since the phosphonate group also has self-extinguishing properties, that is, flame retardancy, its safety performance is further improved.

[0031] (2) The porous structure of MOF materials provides abundant transport channels for lithium ions, and its unsaturated metal sites can interact with anions (such as TFSI) - ) interact strongly, optimizing the transfer path of lithium ions. For example, TFSI - The sulfonyl oxygen atom in TFSI has a lone pair of electrons and can act as a ligand to coordinate with metal ions. - The anchoring effect further improves the ionic conductivity of the solid electrolyte.

[0032] (3) Metal-organic frameworks (MOFs) are typical organic-inorganic hybrid systems, and their unique structural properties stem from the synergistic effect of organic ligands and metal-oxygen cluster nodes. The MOF solid electrolyte disclosed in this invention has high mechanical strength and can effectively inhibit the growth of lithium dendrites, significantly improving the safety and cycle stability of batteries.

[0033] (4) MOF-based solid electrolytes have high porosity, adjustable structure, and abundant lithium ion transport sites, which can significantly improve ionic conductivity. Taking Zr-ATMP as an example, the abundant phosphonic acid groups serve as lithium ion transport sites, and high-valent zirconium ions can anchor lithium salt anions. The ionic conductivity can reach 1.01×10 -4 Scm -1 .

[0034] (5) The present invention adopts a solvent-free dry process for the MOF loading of LiTFSI. The loading of lithium salt can be completed only by mechanical grinding and heated melt infiltration, avoiding the dependence on organic solvents (such as DMF, PC, DME, etc.) in the preparation of traditional MOF electrolytes. The safety hazards brought by flammable and volatile solvents are eliminated from the source, while reducing environmental pollution, which is in line with the concept of green manufacturing. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is an appearance diagram of the MOF solid electrolyte sheet prepared in Example 1 of the present invention;

[0036] Figure 2 Schematic diagram of the electrochemical impedance spectroscopy (a) and Arrhenius curve (b) test results of a stainless steel-stainless steel symmetrical button cell constructed with the MOF solid electrolyte prepared in Example 1 of the present invention;

[0037] Figure 3 1 is a linear sweep voltammetry (LSV) curve of the MOF solid electrolyte sheet prepared in Example 1 of the present invention;

[0038] Figure 4 This is a schematic diagram of the results of lithium-lithium symmetric battery cycle testing of the MOF solid electrolyte prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0039] The technical solutions of the present invention are described below by means of specific embodiments in conjunction with the accompanying drawings. It should be understood that one or more steps mentioned in the present invention do not exclude the existence of other methods and steps before and after the combined steps, or other methods and steps may be inserted between these explicitly mentioned steps. It should also be understood that these examples are only used to illustrate the present invention and are not used to limit the scope of the present invention. Unless otherwise specified, the numbering of each method step is only for the purpose of identifying each method step, and does not limit the order of arrangement of each method or limit the scope of implementation of the present invention. Changes or adjustments in their relative relationships can also be regarded as the scope of implementation of the present invention without substantial changes in the technical content.

[0040] The sources of the raw materials and instruments used in the examples are not particularly limited and can be purchased from the market or prepared according to conventional methods known to those skilled in the art.

[0041] A method for preparing a phosphonic acid-based metal organic framework solid electrolyte comprises the following steps:

[0042] (1) After mixing a metal salt, an organic phosphonic acid ligand, and an organic solvent, a coordination reaction is carried out, wherein the coordination reaction temperature is 120-150° C., the coordination reaction time is 12-15 hours, and the molar ratio of the metal salt to the organic phosphonic acid ligand is 1:0.8-1:1.2;

[0043] (2) filtering the product obtained in step (1), washing, drying, and grinding into powder to obtain MOF powder;

[0044] (3) The MOF powder is placed in a vacuum environment and heated at a temperature of 150-180°C for 12-24 hours to completely remove the solvent in the pores and activate it;

[0045] (4) Under inert gas protection, mechanically grinding the lithium salt and MOF powder to form a mixture, wherein the mass ratio of lithium salt to MOF powder is 0.25:1 to 1.5:1;

[0046] (5) heating the mixture of step (4) at a high temperature of 250-260° C. for 15-30 min to allow the molten lithium salt to penetrate and fill the MOF pores, and cooling to obtain a solid electrolyte powder;

[0047] (6) The solid electrolyte powder is evenly spread in a mold and cold pressed at a pressure of 3 to 5T for 5 to 10 minutes to obtain a phosphonic acid-based MOF all-solid electrolyte.

[0048] Example 1

[0049] Step 1: Zirconium chloride (0.668 g) was added to 50 mL of N,N-dimethylformamide (DMF) and stirred vigorously at room temperature; after the zirconium chloride was completely dissolved, aminotrimethylenephosphonic acid (1.12 mL) was added (the molar ratio of zirconium chloride to aminotrimethylenephosphonic acid was 1:1.2); the resulting suspension was then transferred to a polytetrafluoroethylene reactor and hydrothermally reacted at 120°C for 12 hours;

[0050] Step 2: Isolate the product by vacuum filtration, wash the residual reactant with DMF first, and then wash with deionized water to eliminate the remaining DMF. The reaction product is then dried at 100 ° C overnight to obtain the phosphonic acid MOF.

[0051] Step 3: Transfer the phosphonic acid-based MOF to a vacuum oven and activate it at 150°C for 24 hours to ensure that there is no residual solvent in the pores;

[0052] Step 4: Take 0.5g of LiTFSI and mechanically grind it with the same mass of phosphonic acid-based MOF for 30 minutes to form a uniform composite powder;

[0053] Step 5: Treat at 250°C for 15 minutes to promote the infiltration of molten LiTFSI into the MOF pores, and then cool to prepare MOF solid electrolyte powder;

[0054] Step 6: Spread the solid electrolyte powder evenly in the mold and cold press it at 3T for 7 minutes to obtain a phosphonic acid-based MOF all-solid electrolyte.

[0055] Figure 1 This is an appearance diagram of the MOF solid electrolyte sheet prepared in Example 1 of the present invention; Figure 1 It shows that the cold pressing method can be used to prepare solid electrolytes with certain mechanical strength, which is different from the traditional methods such as sintering of oxide and sulfide solid electrolytes and film processing of polymer electrolytes.

[0056] Ionic conductivity test

[0057] The ionic conductivity of the MOF-based solid electrolyte prepared in Example 1 was tested by electrochemical impedance spectroscopy (EIS). The test device was a stainless steel||MOF electrolyte||stainless steel symmetrical cell. The test frequency range was 1000 kHz. -1 Hz, and the ionic conductivity is calculated according to the formula σ=L / (R×S), where: σ is the ionic conductivity, L is the thickness of the electrolyte membrane, R is the impedance fitting value, and S is the electrode contact area.

[0058] Figure 2In the figure a and b are the impedance spectra and Arrhenius curves of the MOF solid electrolyte prepared in Example 1 at different temperatures. The calculated ionic conductivity of the MOF-based solid electrolyte at 30°C is 1.01×10 -4 S cm -1 .

[0059] Electrochemical stability test

[0060] Using Li||MOF|| stainless steel system, at 10mV s -1 The electrochemical window was tested at the scan rate, and the results were as follows Figure 3 As shown, the decomposition voltage of MOF solid electrolyte can reach 4.4V, showing good electrochemical stability.

[0061] Lithium-lithium symmetric battery cycle test

[0062] At 0.05 mA cm -2 The interfacial stability of the MOF solid electrolyte was tested at a current density of 1000 nm. The test results showed that the battery cycle life exceeded 600 hours without significant increase in polarization ( Figure 4 ).

[0063] The preparation method of the present invention does not require complex synthesis equipment or high-temperature sintering. Simply by increasing the temperature appropriately, the lithium salt can be evenly distributed throughout the MOF pores in a short period of time. This low-energy, low-cost, and easy-to-operate process helps improve the feasibility of large-scale production while ensuring the stability of product performance.

[0064] Example 2

[0065] In the LiTFSI loading experiment at different temperatures, a mixed powder of 1 g MOF and 1.5 g LiTFSI was treated at 260° C. for 15 minutes to promote the complete infiltration of LiTFSI in the MOF pores. Other preparations were the same as in Example 1.

[0066] Example 3

[0067] Cobalt chloride (0.372 g) was selected as the metal ion (the molar ratio of cobalt chloride to aminotrimethylenephosphonic acid was 1:1.2), and the other procedures were the same as in Example 1.

[0068] Example 4

[0069] Step 1: Zirconium chloride (0.668 g) was added to 50 mL of N,N-dimethylformamide (DMF) and stirred vigorously at room temperature; after the zirconium chloride was completely dissolved, aminotrimethylenephosphonic acid (0.747 mL) was added (the molar ratio of zirconium chloride to aminotrimethylenephosphonic acid was 1:0.8); the resulting suspension was then transferred to a polytetrafluoroethylene reactor and hydrothermally reacted at 150°C for 15 hours;

[0070] Step 2: Isolate the product by vacuum filtration, wash the residual reactant with DMF first, and then wash with deionized water to eliminate the remaining DMF. The reaction product is then dried at 100 ° C overnight to obtain the phosphonic acid MOF.

[0071] Step 3: Transfer the phosphonic acid-based MOF to a vacuum oven at 180°C for 12 hours to ensure that there is no residual solvent in the pores;

[0072] Step 4: Take 0.5g LiTFSI and mechanically grind it with 1.5g phosphonic acid-based MOF for 30 minutes to form a uniform composite powder;

[0073] Step 5: Treat at 260°C for 30 minutes to promote the infiltration of molten LiTFSI into the MOF pores, and then cool to prepare MOF solid electrolyte powder;

[0074] Step 6: Spread the solid electrolyte powder evenly in the mold and cold press it at 5T for 10 minutes to obtain a phosphonic acid-based MOF all-solid electrolyte.

[0075] The performance test of the phosphonic acid MOF solid electrolyte prepared in Examples 2-4 showed that the ionic conductivity was within the range of 10 -4 Scm -1 The room temperature ionic conductivity is of the order of magnitude, and the room temperature lithium-lithium symmetric battery cycle test is excellent, which is consistent with Example 1.

[0076] Example 5

[0077] A method for preparing a solid electrode having a solid electrolyte prepared in Example 1, comprising:

[0078] LiFePO4 cathode material, MOF electrolyte powder, conductive agent Super P and binder PVDF were mixed in a mass ratio of 7:1:1:1 and ball milled for 24 h to obtain a uniform MOF-modified cathode composite material;

[0079] The MOF-modified positive electrode composite material is spread on the surface of the MOF electrolyte sheet; secondary cold pressing is performed under a pressure of 5T to form an integrated structure with a seamless interface between the solid electrolyte and the electrode.

[0080] Example 6

[0081] A lithium metal battery comprises a positive electrode, a negative electrode and the MOF solid electrolyte prepared in Example 1.

[0082] Specifically, the solid electrolyte and electrode seamless interface integrated structure prepared in Example 5 is laminated to the surface of lithium metal, and then packaged to obtain an all-solid-state lithium battery.

[0083] The foregoing descriptions of specific exemplary embodiments of the present invention are for purposes of illustration and description. These descriptions are not intended to limit the invention to the precise forms disclosed, and it is apparent that many modifications and variations are possible in light of the foregoing teachings. The exemplary embodiments have been selected and described to explain the specific principles of the invention and their practical application, thereby enabling those skilled in the art to realize and utilize various exemplary embodiments of the invention, as well as various alternatives and variations. It is intended that the scope of the invention be defined by the claims and their equivalents.

[0084] Comparative Example 1

[0085] The reaction ratios of different metal ions and ligand molecules were the same as those in Example 1. The amount of aminotrimethylenephosphonic acid added was 0.373 mL (molar ratio 1:0.4).

[0086] Comparative Example 1 and Example 1 both have the performance of conducting lithium ions. The difference is mainly reflected in the level of ionic conductivity. The ionic conductivity of the electrolyte obtained in Comparative Example 1 is between 10 -5 ~10 -6 S cm -1 Order of magnitude. Since the organic phosphonic acid ligand used in Comparative Example 1 is relatively small, the number of phosphate coordination sites in the prepared MOF is limited, and its ability to fix and transport lithium ions is restricted, resulting in limited migration of lithium ions within the framework. This discontinuity of the local lithium ion transport path weakens the effectiveness of ion transitions, thereby reducing the overall ionic conductivity. In addition, the limited coordination sites may not be able to effectively dissociate LiTFSI, making lithium ions mainly rely on the accompanying migration of anions, thereby further inhibiting the independent transport ability of lithium ions.

[0087] Comparative Example 2

[0088] The difference between this comparative example and Example 1 is that the molar ratio of zirconium chloride to aminotrimethylenephosphonic acid is 1:2, and the other contents are the same as those in Example 1.

[0089] Excess ATMP cannot participate in coordination and is in the protonated form (H4ATMP + ) are adsorbed in the pores, occupying the MOF pores, hindering the coordination of lithium ions with the phosphonic acid groups in the pores, making it impossible to form a continuous ion conduction pathway and making the ion conductivity unmeasurable.

[0090] Comparative Example 3

[0091] The difference between this comparative example and Example 1 is that the mass of the phosphonic acid group MOF in step 4 is 2.5 g, and the mass ratio of the phosphonic acid group MOF to LiTFSI is 5:1. The other aspects are the same as those in Example 1.

[0092] The LiTFSI loading is too low, resulting in insufficient number of mobile Li+, making efficient ion transport difficult and ionic conductivity unmeasurable.

[0093] Comparative Example 4

[0094] The difference between this comparative example and Example 1 is that the activation temperature in step 3 is 100° C., and the rest is the same as Example 1.

[0095] Since the coordination solvent (such as DMF) is not completely removed due to low-temperature activation, it occupies the open metal sites (OMS) of MOF, reducing the anchoring effect of TFSI anions; at the same time, the solvent molecules compete with LiTFSI for adsorption, resulting in the inability of the molten salt to effectively infiltrate the pores, blocking the Li + Coordination site, ionic conductivity is unmeasurable.

[0096] Comparative Example 5

[0097] The difference between this comparative example and Example 1 is that the melting temperature in step 5 is 300° C., and the rest is the same as Example 1.

[0098] Because the melting temperature is too high, the high temperature environment will destroy the structural stability of the phosphonic acid-based MOF; at the same time, LiTFSI will decompose at high temperatures, the electrolyte function will fail, and the ionic conductivity will be unmeasurable.

[0099] Comparative Example 6

[0100] Using UiO-66 as a lithium salt carrier, the ligand used for UiO-66 was terephthalic acid. The specific steps were as follows: 0.53g ZrCl4 (2.28mmol) and 0.38g terephthalic acid (BDC) (2.28mmol) were dissolved in 50mL DMF, 8mL acetic acid was added, and the mixture was solvothermally reacted at 120°C for 24h. The mixture was washed with DMF and methanol in sequence, and vacuum activated at 150°C for 12h. Subsequently, the UiO-66 powder was mixed with LiTFSI in a mass ratio of 1:1 and mechanically ball-milled for 7h. The mixture was heated at 250°C for 30 minutes. The resulting electrolyte powder was cold-pressed at 3T to form an electrolyte sheet.

[0101] The solid electrolyte based on UiO-66 prepared in Comparative Example 6 failed to measure the ionic conductivity at room temperature. The main reason is that although the porous structure of UiO-66 provides a certain migration space for lithium ions, the carboxylate groups (-COO - ) has a lower charge density than the phosphonate group, and its coordination ability with lithium ions is weak, making it unable to effectively transport lithium ions. In the absence of phosphate functional groups, UiO-66 cannot take advantage of the advantages of the Zr-ATMP structure. The lack of phosphate means that lithium ions lack the necessary "jump point", which greatly hinders the migration of lithium ions in the UiO-66 matrix.

[0102] The foregoing descriptions of specific exemplary embodiments of the present invention are for purposes of illustration and description. These descriptions are not intended to limit the invention to the precise forms disclosed, and it is apparent that many variations and modifications are possible in light of the foregoing teachings. The exemplary embodiments have been selected and described for the purpose of explaining the specific principles of the invention and their practical application, thereby enabling those skilled in the art to realize and utilize a variety of exemplary embodiments of the invention and various options and modifications. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A method for preparing a phosphonic acid-based metal organic framework solid electrolyte, characterized in that: The specific steps include: (1) After mixing a metal salt, an organic phosphonic acid ligand, and an organic solvent, a coordination reaction is carried out, and after the reaction is completed, MOF powder is obtained through post-treatment; (2) heating and activating the MOF powder to remove the organic solvent in the MOF pores to obtain activated MOF powder; (3) mechanically grinding the lithium salt and the activated MOF powder to form a mixture; (4) The mixture of step (3) is heated to allow the molten lithium salt to penetrate and fill the MOF pores, and then cooled to obtain a solid electrolyte powder.

2. The preparation method according to claim 1, characterized in that In step (1), the metal salt is one or more of zirconium salt, zinc salt, cobalt salt, magnesium salt, and manganese salt; preferably, the metal salt is one or more of zirconium chloride, zinc chloride, cobalt chloride, magnesium chloride, and manganese chloride; And / or, the organic phosphonic acid ligand is one or more of aminotrimethylenephosphonic acid, hydroxyethylidene diphosphonic acid, ethylenediamine tetramethylenephosphonic acid, and diethylenetriamine pentamethylidenephosphonic acid; And / or, the molar ratio of the metal salt to the organic phosphonic acid ligand is 1:0.8 to 1:1.

2.

3. The preparation method according to claim 1, characterized in that In step (1), the post-treatment includes filtering, washing, drying, and grinding into powder to obtain the MOF powder; And / or, the solvent is DMF; the coordination reaction temperature is 120-150° C.; and the coordination reaction time is 12-15 hours.

4. The preparation method according to claim 1, characterized in that In step (2), the activation method includes: placing the MOF powder in a vacuum environment and heating it to remove the solvent in the MOF pores; Preferably, the heating temperature is 150-180° C., and the heating time is 12-24 hours.

5. The preparation method according to claim 1, characterized in that In step (3), the lithium salt is one or more of lithium perchlorate, lithium nitrate, lithium tetrafluoroborate, lithium hexafluorophosphate, lithium bis(oxalatoborate), lithium difluorooxalatoborate, lithium bis(difluorosulfonylimide), and lithium bis(trifluoromethylsulfonylimide); preferably, the lithium salt is lithium bis(trifluoromethylsulfonylimide); And / or, the content of lithium salt loaded in the MOF is 20 wt% to 60 wt%; And / or, the mass ratio of the lithium salt to the MOF powder in step (3) is 0.25:1 to 1.5:

1.

6. The preparation method according to claim 1, characterized in that In step (4), the heating temperature is 250-260° C. and the heating time is 15-30 minutes.

7. The preparation method according to claim 1, wherein: The invention also includes: pressing the solid electrolyte powder into tablets to obtain a phosphonic acid-based MOF all-solid electrolyte; The tabletting pressure is 3 to 5T and the tabletting time is 5 to 10 minutes.

8. A phosphonic acid-based MOF all-solid-state electrolyte prepared according to the method according to any one of claims 1 to 7.

9. A solid-state electrode comprising the phosphonic acid-based MOF all-solid-state electrolyte according to claim 8.

10. Use of the phosphonic acid-based MOF all-solid electrolyte according to claim 8 in a solid-state lithium battery.

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