Hydrogen-bonding network-based organic polymer crystal material, and preparation method and application thereof

Abstract

The application provides an organic polymer crystal material based on a hydrogen bond network and a preparation method and application thereof, and the material can be used in alkali metal ion batteries. The organic electrode material takes an unsaturated carbonyl group as a redox active site, takes a piperazine structure to connect a benzoquinone monomer to expand a conjugated structure, and can form intermolecular hydrogen bonds, connect polymer molecular chains to realize two-dimensional structure expansion, and finally form a graphite-like layered structure. Through the synergistic coordination of N and O in the structure and metal ions, reversible storage of the metal ions is realized. The organic polymer crystal positive electrode material has the advantages of easy scale production, high capacity, good rate performance, high cycle stability and the like, and has high application value.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of battery organic positive electrode materials, and particularly relates to an organic polymer crystal material based on a hydrogen bond network and a preparation method and application thereof. BACKGROUND

[0002] The rapid development of new energy electric vehicles, large-scale stationary energy storage devices and national smart grids puts forward higher requirements for the energy density, cycle life and resource reserves of rechargeable secondary batteries. Metal ion batteries have attracted widespread attention in recent years due to their high energy density. However, traditional metal ion batteries are often based on inorganic electrode materials such as transition metal oxides and graphite, which usually show low actual energy output or rely on scarce natural resources. In contrast, organic electrode materials have the advantages of abundant sources, high specific capacity, designable structure, green environmental protection, etc. In addition, organic materials are generally not limited by ion selection, and it is feasible to apply the same organic molecules in various metal ion batteries. This makes organic secondary batteries have broad application prospects in the field of large-scale energy storage.

[0003] However, organic electrode materials are usually dissolved in organic electrolyte, and the capacity decay is serious during the cycle process. In addition, their intrinsic conductivity is poor, which limits their rate performance. If the cycle stability and rate performance of organic electrode materials can be effectively improved, their high capacity will be expected to become a candidate material for metal ion batteries. In view of the solubility problem of organic molecules, the reported solutions include salting, polymerization, porous matrix loading, etc., but these methods still have some limitations. The ordinary polymerization strategy will introduce non-active components, reducing the specific capacity; at the same time, polymerization is easy to cause the entanglement of molecular chains, which is not conducive to the full exposure of active sites. From the perspective of molecular structure design, expanding the conjugated structure and improving the intermolecular interaction are also effective strategies to solve the problems of easy dissolution of organic electrode materials in organic electrolyte and poor conductivity. Therefore, it is of great significance to design and synthesize organic electrode materials suitable for reversible ion extraction and insertion through function-oriented molecular structure design strategy in view of the problems of easy solubility and poor conductivity of organic compounds. SUMMARY

[0004] In view of the defects of the prior art and the improvement needs, the application provides an organic polymer crystal material based on a hydrogen bond network, which is used in an alkali metal ion battery, and aims to solve the problems of poor conductivity, dissolution and low active site utilization rate of the existing polymer electrode material in the organic electrode material.

[0005] To achieve the above object, the first aspect of the present application provides an organic polymer crystal material based on hydrogen bond network, which is used as an electrode material of alkali metal ion battery, the organic electrode material takes unsaturated carbonyl as a redox active site, and forms a complex by using the synergistic coordination of carbonyl and N, O in piperazine with metal ions to realize the reversible storage of metal ions, characterized in that the conjugated structure is expanded by connecting the polymer monomer benzoquinone through the piperazine structure to realize rigid polymerization, the N-H bond on the piperazine unit and the C=O on the benzoquinone unit can form intermolecular hydrogen bond, the polymer molecular chain is connected to realize two-dimensional expansion, and finally a graphite-like layered structure is formed.

[0006] The second aspect of the present application provides a preparation method of the above-mentioned organic polymer crystal material based on hydrogen bond network, and the preparation method of the organic electrode material comprises the following steps: dispersing raw materials tetraamino-p-benzoquinone and tetrachloro-p-benzoquinone in a solvent N,N-dimethylformamide, refluxing under an argon atmosphere, and then performing suction filtration, washing and drying to obtain the organic polymer crystal material based on hydrogen bond network.

[0007] Further, in the preparation method of the present application, the amount of the raw materials is that 1 mmol of tetrachloro-p-benzoquinone and 4 mmol of tetraamino-p-benzoquinone are added into 50 ml of N,N-dimethylformamide.

[0008] Further, in the preparation method of the present application, the refluxing reaction is performed under an argon atmosphere for 12 h.

[0009] Further, in the preparation method of the present application, after suction filtration, the filter cake is washed with N,N-dimethylformamide and methanol until colorless, and then vacuum dried to obtain the organic polymer crystal material.

[0010] The present application also provides an alkali metal ion battery, characterized in that the electrode material of one or more electrodes is the organic electrode material as described above.

[0011] Further, the alkali metal is lithium, sodium or potassium.

[0012] Overall, the above technical solutions conceived by the present application can achieve the following beneficial effects:

[0013] (1) The present application provides an organic polymer crystal material based on hydrogen bond network for alkali metal ion battery, which expands the conjugated structure by connecting polymeric monomer benzoquinone through piperazine structure to realize rigid polymerization, wherein the N-H bond on the piperazine unit and the C=O on the benzoquinone unit can form intermolecular hydrogen bond, and the polymer molecular chain is connected to realize two-dimensional expansion, and finally form a layered structure similar to graphite. It uses unsaturated carbonyl as the redox active site, utilizes the synergistic coordination of carbonyl and N, O in piperazine with metal ions to form a complex, and realizes the reversible storage of metal ions. The organic electrode material has flexible structure and can accommodate the insertion / extraction of ions with different radii, and is suitable for various alkali metal ion batteries.

[0014] (2) The organic polymer crystal material based on hydrogen bond network provided by the present application expands the pi conjugated structure through piperazine structure in the molecule, which is beneficial to the rapid transmission of electrons and has excellent conductivity; the intermolecular pi-pi interaction forms an ordered arrangement of graphite-like structure, which is beneficial to the rapid transfer of ions and has excellent rate performance.

[0015] (3) The organic electrode material provided by the present application utilizes piperazine as an active site connection unit and introduces intermolecular hydrogen bond interaction, which is beneficial to stabilizing the molecular structure, solving the problems of dissolution of the organic electrode material in the electrolyte and entanglement of the polymer molecular chain, and improving the cycle stability of the battery.

[0016] (4) The organic electrode material provided by the present application has low cost, simple experimental operation, short reaction time, mild preparation conditions, green environmental protection, recyclability and large-scale synthesis, which provides a new choice, a new direction for green and environmentally friendly, low-cost and large-scale production of organic materials in the energy storage field, and has good commercialization prospects. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 The molecular structure diagram of example 1 provided by the present application is shown in the figure;

[0018] Figure 2 The infrared spectrum of example 1 provided by the present application is shown in the figure;

[0019] Figure 3 The XRD spectrum of example 1 provided by the present application is shown in the figure;

[0020] Figure 4 The first ten cycles of sodium battery charge-discharge curves of example 2 provided by the present application are shown in the figure;

[0021] Figure 5 The cycle performance diagram of sodium battery of example 2 provided by the present application is shown in the figure;

[0022] Figure 6 a sodium battery rate performance graph of Example 2 provided for the present application;

[0023] Figure 7 a lithium battery charge-discharge curve of Example 2 provided for the present application;

[0024] Figure 8 electronic conductivity of Example 1 and Comparative Example 1 provided for the present application;

[0025] Figure 9 a sodium battery cycle performance graph of Comparative Example 1 provided for the present application. DETAILED DESCRIPTION

[0026] The present application will be further explained by the accompanying drawings and specific examples, which are only illustrative and should not be understood as limiting the scope of the present application, and the protection scope of the present application is not limited to the following examples.

[0027] Example 1

[0028] A design and preparation method of an organic polymer crystal material based on a hydrogen bond network, the chemical formula of the positive electrode material is (C6H2N2O2) n The organic electrode material uses unsaturated carbonyl as a redox active site, uses the synergistic coordination of carbonyl and N, O in piperazine with metal ions to form a complex, and realizes reversible storage of metal ions, Figure 1 A molecular structure diagram of Example 1. The organic polymer crystal material of the present application expands the conjugated structure by connecting the polymer monomer benzoquinone through the piperazine structure, realizes rigid polymerization, wherein the N-H bond on the piperazine unit and the C=O on the benzoquinone unit can form intermolecular hydrogen bonds, connect the polymer molecular chain to realize two-dimensional expansion, and finally form a graphite-like layered structure.

[0029] The organic electrode material described above, the preparation method thereof comprises the following steps:

[0030] Take 1 mmol of tetrachlorobenzoquinone and 4 mmol of tetraaminobenzoquinone, add 50 ml of N,N-dimethylformamide, and then reflux under inert atmosphere for 12 h. After cooling to room temperature, suction filtration, and washing the filter cake with N,N-dimethylformamide and methanol until colorless, vacuum drying, an ink green solid PTABQ is obtained. Figure 2 and Figure 3 The infrared spectrum and XRD spectrum of Example 1, respectively.

[0031] Example 2

[0032] The application further provides application of the electrode material. The organic polymer crystal material has an extended pi conjugated structure through a piperazine structure in the molecule, is beneficial to fast transmission of electrons, and has excellent conductivity; the organic polymer crystal material forms an ordered arrangement of a graphite-like structure through pi-pi interaction between molecules, is beneficial to fast transfer of ions, and has excellent rate performance. The organic electrode material has structural flexibility, can accommodate embedding and extraction of ions with different radii, can be used as an electrode material of an alkali metal ion battery, and is suitable for various alkali metal ion batteries.

[0033] Based on the above description, the application further provides an alkali metal ion battery containing the electrode material.

[0034] The preparation method of the alkali metal ion battery in the embodiment is as follows: the PTABQ in Example 1, conductive carbon (SuperP) and a binder (PVDF) are ground and mixed uniformly at a mass ratio of 5:4:1, and then transferred into a homogenizing box, and an appropriate amount of N-methyl pyrrolidone is added. After being mixed uniformly in a homogenizer, the slurry is coated on an aluminum foil by using a doctor blade, and then dried in a 60°C air oven for 6 hours and then dried in a 100°C vacuum oven for 12 hours. A punching machine is used to obtain a round sheet with a diameter of 10 mm.

[0035] In an argon glove box, a PTABQ positive electrode and a metal sodium negative electrode are assembled into a button cell by using 1.0M NaPF6DEGDME as an electrolyte and Celgard 2400 as a separator, and used for testing of sodium battery electrochemical performance.

[0036] In an argon glove box, a PTABQ positive electrode and a metal lithium negative electrode are assembled into a button cell by using 1.0M LiTFSIDOL / DME as an electrolyte and Celgard 2400 as a separator, and used for testing of lithium battery electrochemical performance.

[0037] Figure 1 shows a schematic diagram of a button cell. Figure 4 Description: The PTABQ material has a specific capacity as high as 350 mAh g -1 , a discharge average voltage of about 2V, good cycle reversibility and stability, almost no capacity attenuation in the first ten cycles, and reversible sodium ion storage capacity.

[0038] Figure 2 shows a schematic diagram of a button cell. Figure 5 Description: The PTABQ material has excellent cycle stability, and the capacity retention rate is still 94.6% after 200 cycles at a current density of 500 mAg -1 . This is due to the structural characteristics of the PTABQ, which has good dissolution inertness and good stability in the charging and discharging cycle process.

[0039] Figure 3 shows a schematic diagram of a button cell. Figure 6Note: PTABQ exhibits excellent rate capability up to 5 Ag. -1 It can still perform at a current density of nearly 200mAh g -1 The capacity is attributed to the enhanced conductivity of the material due to the extended conjugated structure, which provides a fast ion transport channel.

[0040] Appendix Figure 7 Note: PTABQ material also exhibits reversible lithium-ion storage capacity in lithium batteries, with a capacity of 350 mAh / g. -1 The specific capacity of around 2.4V and the discharge voltage of around 2.4V indicate that the PTABQ cathode is suitable for various alkali metal ion batteries.

[0041] Comparative Example 1

[0042] A small molecule organic cathode material, PTABQ material, is a polymer monomer of 1,2,4,5-tetraaminop-benzoquinone (TABQ).

[0043] TABQ was prepared into a positive electrode as described in Example 2. In an argon glove box, using 1.0 M NaPF6DEGDME as the electrolyte and Celgard 2400 as the separator, the TABQ positive electrode and the sodium metal negative electrode were assembled into a button cell, and the electrochemical performance was tested.

[0044] Figure 8 The electronic conductivity of the material in Example 1 is compared with that of the material in Comparative Example 1. The conductivity of the material in Example 1 is two orders of magnitude higher than that of the material in Comparative Example 1, indicating that the proposed method of using piperazine as an active site linker to extend the conjugated structure improves the conductivity of the material. Figure 9 The graph shows the long-cycle performance of Comparative Example 1, at a cycle length of 500 mA g. -1 After 100 cycles at a current density, the capacity retention rate of Example 2 was only 74%, while at 500 mA g -1 The capacity retention rate was 94.6% after 200 cycles at the current density. This is attributed to the use of piperazine as an active site linker proposed in this invention, which introduces intermolecular hydrogen bonding interactions, stabilizes the molecular structure, solves the problem of organic electrode materials dissolving in the electrolyte, and thus improves the cycle stability of the battery.

[0045] The organic electrode material provided by the application utilizes piperazine as an active site connecting unit, introduces intermolecular hydrogen bond interaction, is conducive to stabilizing the molecular structure, solves the problems of dissolution of the organic electrode material in an electrolyte and entanglement of polymer molecular chains, and improves the cycle stability of the battery. Meanwhile, the organic electrode material has the advantages of low cost, simple experimental operation, short reaction time, mild preparation conditions, green environmental protection, recyclability and large-scale synthesis, which provides a new choice, a new direction for the organic material used in the energy storage field, and has good commercialization prospects.

Claims

1. An organic polymer crystalline material based on a hydrogen-bonding network, characterized in that, The raw material tetraaminoparabenzoquinone and tetrachloroparabenzoquinone are dispersed in solvent N,N-dimethylformamide, refluxed under argon atmosphere, filtered, washed and dried to obtain an organic polymer crystal material based on hydrogen bond network; the chemical formula of the organic polymer crystal material is (C6H2N2O2) n The material is widely used in alkali metal ion batteries, and the organic electrode material takes the unsaturated carbonyl as a redox active site, utilizes the synergistic coordination of the carbonyl and N and O in the piperazine with metal ions to form a complex, and realizes reversible storage of metal ions.

2. The organic polymer crystalline material according to claim 1, characterized by The conjugated structure is extended by connecting polymeric monomer benzoquinone through piperazine structure, realizing rigid polymerization, wherein N-H bond on piperazine unit and C=O on benzoquinone unit can form intermolecular hydrogen bond, connecting polymer molecular chain to realize two-dimensional extension, and finally forming graphite-like layered structure.

3. The method for producing a hydrogen-bond network-based organic polymer crystal material according to claim 1 or 2, characterized by The method comprises the following steps: dispersing raw materials tetraamino-p-benzoquinone and tetrachloro-p-benzoquinone in a solvent N,N-dimethylformamide, refluxing and reacting under an argon atmosphere, and then performing suction filtration, washing and drying to obtain the organic polymer crystal material based on hydrogen bond network. The amount of the raw materials is as follows: 1 mmol of tetrachloro-p-benzoquinone and 4 mmol of tetraamino-p-benzoquinone are added into 50 ml of N,N-dimethylformamide.

4. The production method according to claim 3, characterized by, The reaction is performed under an argon atmosphere for 12 h.

5. The preparation method according to claim 3, characterized in that, After suction filtration, the filter cake is washed with N,N-dimethylformamide and methanol until colorless, and then vacuum dried to obtain the organic polymer crystal material.

6. An alkali metal ion battery characterized in that, The electrode material of one electrode or multiple electrodes is the organic polymer crystal material according to claim 1 or 2.

7. An alkali metal-ion battery according to claim 6, wherein, The alkali metal is lithium, sodium or potassium.

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