A type of carbonyl-containing phenazine polymer and its preparation method and application

Abstract

The present invention belongs to the technical field of battery materials, and specifically discloses a class of carbonyl-containing phenazine polymers and a preparation method and application thereof. The carbonyl-containing phenazine polymers have multiple phenazine structures, increase the number of conjugated rings, and retain some carbonyl electroactive sites to achieve multi-charge storage, thereby obtaining excellent charge-discharge specific capacity and good cycle stability, and have good application prospects in the field of aqueous battery electrode materials.

Description

Technical Field

[0001] The invention belongs to the technical field of battery materials, and in particular relates to a type of carbonyl-containing phenazine polymer and a preparation method and application thereof. Background Art

[0002] As battery safety issues become increasingly prominent and environmental pollution becomes more serious, it is urgent to develop safe, reliable, and eco-friendly energy storage devices. Aqueous batteries constructed with water as the electrolyte solvent can fundamentally solve the safety and environmental problems caused by flammable organic electrolytes, while avoiding the strict manufacturing conditions and expensive electrolyte costs of organic systems. Therefore, they are widely considered to be the most promising energy storage devices for large-scale energy storage systems.

[0003] Organic materials containing only carbon, hydrogen, oxygen and other elements are one of the hot topics of global concern, especially in the field of battery energy storage, with great development potential. Compared with non-electrode materials, organic materials are widely available, low-cost, green and environmentally friendly, have good structural flexibility, and are easy to regulate their electrochemical properties. At the same time, the volume expansion and structural changes during charging and discharging are not obvious. However, the small number of redox active sites in organic materials limits the theoretical capacity of the battery to a certain extent. For example, the public patent document "Organic electrode materials, preparation methods and applications thereof" with publication number CN111261872A discloses compounds containing carbazole functional groups. In addition, organic materials are easily soluble in aqueous electrolytes, and the dissolved active substances lose contact with the electrodes, resulting in poor electrode cycle stability, such as "Research on carbonyl and imine organic compounds in new aqueous proton battery negative electrodes" Han Wenjuan, HowNet data platform, January 2022, Chapter 3 5,7,12,14-pentacene tetraketone organic materials. Summary of the invention

[0004] Purpose of the invention: In order to solve the above technical problems, the present invention aims to provide a type of carbonyl-containing phenazine polymer with multiple active sites, high capacity, not easily soluble in aqueous electrolytes and good cycle stability. The present invention also provides a preparation method and application of the polymer.

[0005] In a first aspect, the present invention provides a class of carbonyl-containing phenazine polymers, comprising the following structure:

[0006]

[0007] In the above chemical formulas (I), (II) and (III), the value of n ranges from 1 to 200.

[0008] In a second aspect, the present invention also provides a method for preparing the carbonyl-containing phenazine polymer, comprising the following steps: adding a polyketone compound, 3,3,4,4-tetraaminobenzophenone and an organic solvent to a reactor under the protection of an inert gas, reacting the reaction mixture under reflux and heating conditions while stirring, stopping heating after sufficient reaction, cooling to room temperature, taking out, centrifuging, washing, and purifying to obtain a solid product, namely, a carbonyl-containing phenazine polymer, wherein the final yield is calculated to be 70%-85%;

[0009] The polyketone compound is selected from any one of pyrene-4,5,9,10-tetraketone, cyclohexanehexaketone octahydrate, and triphenylene-2,3,6,7,10,11-hexaketone;

[0010] When the polyketone compound is pyrene-4,5,9,10-tetraketone, the reaction equation is as shown in the following formula (I):

[0011]

[0012] When the polyketone compound is cyclohexanone octahydrate, the reaction equation is as shown in the following formula (II):

[0013]

[0014] When the polyketone compound is triphenylene-2,3,6,7,10,11-hexaketone, the reaction equation is shown in the following formula (III):

[0015]

[0016] Preferably, in order to improve the utilization rate of raw materials, the molar ratio of the polyketone compound to 3,3,4,4-tetraaminobenzophenone is 1:1.

[0017] Further, the inert gas is one of nitrogen or argon;

[0018] Furthermore, the organic solvent is acetic acid, the reaction is carried out at an initial temperature of 60°C for 2 hours, the temperature is increased to 120°C at a rate of 5°C / min and the reaction is carried out at this temperature for 4-32 hours.

[0019] Furthermore, the washing solutions used in the washing step include hot acetic acid at 35-45°C, acetone, water at 25-30°C and ethanol in sequence, and each washing solution is used for 1-3 times to preliminarily remove the unreacted precursors remaining in the product.

[0020] Furthermore, the purification step is: the washed product is fully stirred in a hot nitric acid solution at 120-140°C, then washed with a solvent and vacuum dried at 85-90°C to further remove the unreacted precursors remaining in the product to obtain a high-purity carbonyl-containing phenazine polymer. Further preferably, the mass fraction of the hot nitric acid solution is 35wt%. Further preferably, the solvent is deionized water and ethanol.

[0021] In a third aspect, the present invention also provides the use of the carbonyl-containing phenazine polymer in the preparation of electrode materials for aqueous batteries.

[0022] Furthermore, the preparation method of the electrode material is: mixing and grinding a carbonyl-containing phenazine polymer, a conductive additive and an adhesive to obtain a slurry; evenly coating the slurry on the surface of a conductive carbon paper, drying and slicing to obtain the electrode material.

[0023] Furthermore, the mass ratio of the polyketone compound, the conductive additive and the adhesive is (6-8):(3-1):(1-1); further preferably, the conductive additive is acetylene black, the adhesive is polyvinylidene fluoride, and the mass ratio of the polyketone compound, the conductive additive and the adhesive is 7:2:1.

[0024] Principle of the invention: The present invention successfully synthesized carbonyl-containing phenazine polymers by designing the molecular structure to form a polyphenazine structure while retaining some carbonyl electroactive sites. The formed polyphenazine structure can increase the number of conjugated rings, thereby enhancing the cyclic stability of the electrode material, while providing more redox active sites and improving the charge-discharge specific capacity of the electrode material. In addition, the retained carbonyl group, as an electron-withdrawing group, can reduce the molecular energy gap and enhance the electron transmission capacity, thereby optimizing the performance of the electrode material.

[0025] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0026] (1) Compared with the compounds containing carbazole functional groups disclosed in the patent document "Organic electrode materials, preparation methods and applications thereof" described in the background art, the carbonyl-containing phenazine polymers provided by the present invention have the advantage of having more redox active sites: the carbonyl-containing phenazine polymers provided by the present invention not only retain part of the carbonyl electroactive sites, but also can effectively reduce the molecular energy gap; at the same time, the formed multi-phenazine structure provides more redox active sites, thereby improving the charge-discharge specific capacity of the electrode material, and showing good application prospects in the field of aqueous battery electrode materials;

[0027] (2) Compared with the 5,7,12,14-pentacenetetraone organic material disclosed in Chapter 3 of the public paper "Research on Carbonyl and Imine Organic Compounds in the Negative Electrode of Novel Aqueous Proton Batteries" described in the background technology, the carbonyl-containing phenazine polymer provided by the present invention has better cycle stability as an electrode material in aqueous batteries than other electrode materials. The carbonyl-containing phenazine polymer provided by the present invention increases the number of polymer conjugated rings through the polyphenazine structure, effectively inhibits the dissolution of the electrode material, ensures the cycle stability of the electrode material, and shows good application prospects in the field of aqueous battery electrode materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a scanning electron microscope image of the carbonyl-containing phenazine polymer prepared in Example 1 of the present invention;

[0029] Figure 2 This is an element distribution diagram of the carbonyl-containing phenazine polymer prepared in Example 1 of the present invention;

[0030] Figure 3 This is an infrared spectrum of the carbonyl-containing phenazine polymer prepared in Example 1 of the present invention;

[0031] Figure 4 This is the XPS C 1s spectrum of the carbonyl-containing phenazine polymer prepared in Example 1 of the present invention;

[0032] Figure 5 This is the XPS N 1s spectrum of the carbonyl-containing phenazine polymer prepared in Example 1 of the present invention;

[0033] Figure 6 This is the XPS O 1s spectrum of the carbonyl-containing phenazine polymer prepared in Example 1 of the present invention;

[0034] Figure 7 Graphs of cyclic voltammetry (CV) of the carbonyl-containing phenazine polymer prepared in Example 1 of the present invention at different scan rates;

[0035] Figure 8 The constant current charge-discharge curve (GCD) of the carbonyl-containing phenazine polymer prepared in Example 1 of the present invention at different current densities;

[0036] Fig. 9 The carbonyl-containing phenazine polymer prepared in Example 1 of the present invention was subjected to 20A g -1 The charge and discharge curve cycle diagram of 20,000 cycles under the current density;

[0037] Fig.10 For Examples 1-3 of the present invention at 1Ag -1 Comparison of mass specific capacity under current density.

[0038] Fig.11 For example 1, example 4, and example 5 of the present invention, at 1Ag -1 Comparison of mass specific capacity under current density.

[0039] Fig.12 It is a comparison chart of mass specific capacity of Example 1, Example 6 and Example 7 at different current densities. Specific implementation methods

[0040] The present invention is further described below in conjunction with specific embodiments and drawings.

[0041] The sources of raw materials, reagents and test equipment in the following examples and tests are as follows:

[0042] 3,3,4,4-Tetraaminobenzophenone, also known as bis(3,4-diaminophenyl)ketone, Picasso, purity 97%;

[0043] Pyrene-4,5,9,10-tetraone, Yanshen Technology, purity 97%;

[0044] Scanning electron microscope, Zeiss, Germany, Merlin Compact;

[0045] Fourier transform infrared spectroscopy, Agilent, USA, FTS2000;

[0046] X-ray radiometer, Shimadzu Corporation, Japan, XRD-6000KE1207.

[0047] Example 1

[0048] The preparation method of the carbonyl-containing phenazine polymer (I) of Example 1 is as follows: 0.262 g (1 mmol) of pyrene-4,5,9,10-tetraketone (Yanshen Technology, purity 97%) and 0.242 (1 mmol) of 3,3,4,4-tetraaminobenzophenone (Picasso, purity 97%) were added to a ball mill and ground for 2 hours to ensure that the drugs were finely ground and mixed evenly. The ground drugs were added to a reactor under nitrogen protection and dissolved in 40 ml of acetic acid. The reaction mixture was stirred and reacted under reflux. After reacting at 60°C for 2 hours, the temperature was raised to 120°C at a rate of 5°C / min and reacted at this temperature for 8 hours. After the reaction was completed, the heating was stopped, the mixture was cooled to room temperature, and the solid product was washed by centrifugation. The product obtained after centrifugation was washed with hot acetic acid, acetone, water and ethanol at 35-45°C and then in 50 ml of 35wt% HNO 3 The mixture was stirred at 140° C. for 3 hours, washed with deionized water and ethanol, and dried in vacuo at 90° C. to obtain a carbonyl-containing phenazine polymer (I).

[0049] Figure 1The scanning electron micrograph of the phenazine polymer containing carbonyl group (scanning electron microscope, Zeiss, Germany, Merlin Compact);

[0050] Figure 2 From left to right are the distribution diagrams of C, N, and O elements. Figure 2 It can be seen that the distribution of C, N, and O elements is relatively uniform, indicating that the polyketone compounds react fully with 3,3,4,4-tetraaminobenzophenone and the generated multiple phenazine structures are evenly distributed.

[0051] Figure 3 The infrared spectrum of the carbonyl-containing phenazine polymer powder (Fourier transform infrared spectroscopy, Agilent, USA, FTS2000), where 1634, 1529 and 1408 cm -1 The peaks at are attributed to C=O, C=N and CN bonds, respectively.

[0052] Figure 4 This is the XPS C 1s spectrum of the carbonyl-containing phenazine polymer (X-ray spectrometer, Shimadzu Corporation, Japan, XRD-6000KE1207), the peaks at 284.8, 285.47 and 286.89 correspond to the CC / C=C, CN / C=N and C=O bonds in the polymer, respectively. In addition, a clear peak can be observed at 289.7 eV, which is the π-π interaction between the carbonyl-containing phenazine polymers.

[0053] Figure 5 This is the XPS N 1s spectrum of a carbonyl-containing phenazine polymer. The peaks at 398.7 and 400.3 eV correspond to the polymer C=N and CN bonds, respectively. Figure 2 Infrared spectra and Figure 4 XPS C 1s spectrum analysis showed that the C=N and CN bonds originated from the phenazine structure, proving that the carbonyl-containing phenazine polymers successfully formed multiple phenazine structures through molecular structure design.

[0054] Figure 6 This is the XPS O 1s spectrum of a carbonyl-containing phenazine polymer. The peak at 531.6 eV corresponds to the C=O bond of the polymer. Figure 2 Infrared spectrum analysis showed that there was a C=O bond in the polymer, which originated from the carbonyl group in the precursor 3,3,4,4-tetraaminobenzophenone, indicating that the prepared polymer successfully retained some carbonyl groups.

[0055] In addition to the above Example 1, the following examples were prepared in a similar manner by changing some of the raw materials, reaction parameters or conditions;

[0056] Example 2: The difference from Example 1 is that after reacting at 60°C for 2 hours, the temperature is raised to 120°C at a rate of 5°C / min and reacted at this temperature for 4 hours.

[0057] Example 3: The difference from Example 1 is that after reacting at 60°C for 2 hours, the temperature is raised to 120°C at a rate of 5°C / min and reacted at this temperature for 32 hours.

[0058] Example 4: The difference from Example 1 is that during the purification process, vacuum drying at 60°C for 12 hours is adopted.

[0059] Example 5: The difference from Example 1 is that during the purification process, vacuum drying at 120°C for 12 hours is adopted.

[0060] Example 6: The difference from Example 1 is that the polyketone compound is changed to cyclohexanone octahydrate, and the molar ratio of cyclohexanone octahydrate to 3,3,4,4-tetraaminobenzophenone is 1:1.

[0061] Example 7: The difference from Example 1 is that the polyketone compound is changed to triphenylene-2,3,6,7,10,11-hexaone, and the molar ratio of triphenylene-2,3,6,7,10,11-hexaone to 3,3,4,4-tetraaminobenzophenone is 1:1.

[0062] Electrochemical performance test of the carbonyl-containing phenazine polymers prepared in Examples 1-7

[0063] First, a carbonyl-containing phenazine polymer electrode sheet is prepared. The preparation method includes: before the electrode is prepared, the dried carbonyl-containing phenazine polymer is ground in a mortar to ensure uniform mixing. The carbonyl-containing phenazine polymer, acetylene black (TIMCAL, Switzerland, analytical grade) and a binder, namely polyvinylidene fluoride (Arkema, France, analytical grade) are dispersed in 1-methyl-2-pyrrolidone (NMP) (National Pharmaceutical Group, analytical grade) at a weight ratio of 7:2:1, and the mixture is stirred in a high-speed stirrer for 30 minutes to form a uniform slurry. The slurry is then evenly hung on a conductive carbon paper and vacuum dried at 60°C for 12 hours to obtain a carbonyl-containing phenazine polymer electrode sheet for a working electrode.

[0064] The carbonyl-containing phenazine polymer electrode was prepared by a three-electrode system using an electrochemical workstation (Wuhan Cost Instrument Co., Ltd., CS350H) at 1 M H 2 SO 4 Electrochemical tests were carried out in electrolyte and the results showed that it had good electrochemical performance.

[0065] Figure 7This is the cyclic voltammetry (CV) curve of the carbonyl-containing phenazine polymer (I) organic electrode prepared in Example 1 of the present invention at different scanning rates. A pair of obvious redox peaks can be observed from the CV curve.

[0066] Figure 8 This is the galvanostatic charge-discharge curve (GCD) of the carbonyl-containing phenazine polymer (I) organic electrode prepared in Example 1 of the present invention at different current densities. The GCD curve shows obvious charge-discharge plateaus, which are consistent with the redox peaks in the CV curve. It can also be seen from the figure that when the current density is 1 Ag -1 , the specific capacity of the carbonyl-containing phenazine polymer electrode is as high as 215 mAh g -1 .

[0067] Fig. 9 This is the charge-discharge curve of the carbonyl-containing phenazine polymer (I) prepared in Example 1 of the present invention at a current density of 20 A g -1 for 20,000 cycles. After 20,000 cycles, the discharge specific capacity decays from 135.74 mAh to 128.47 mAh, and the capacity retention rate is as high as 94.6%. It can be seen that this material has good cycle stability.

[0068] Fig.10 These are the electrodes made of the carbonyl-containing phenazine polymers prepared in Examples 1-3, acetylene black, and polyvinylidene fluoride in a mass ratio of 7:2:1. Their mass specific capacity comparison at a current density of 1 Ag -1 is shown. It can be seen from the figure that when the reaction time is 10 h, the mass specific capacity of the obtained carbonyl-containing phenazine polymer electrode is relatively high. When the reaction time is 10 h and there is a protective gas, the mass specific capacity electrochemical performance is the best, and the electrochemical performance is the best.

[0069] Fig.11 These are the electrodes made of the carbonyl-containing phenazine polymers prepared in Examples 1, 4, and 5, acetylene black, and polyvinylidene fluoride in a mass ratio of 7:2:1. Their mass specific capacity comparison at a current density of 1 Ag -1 is shown. It can be seen from the figure that when the product drying temperature is 90 °C, the mass specific capacity of the obtained carbonyl-containing phenazine polymer electrode is the best, and the electrochemical performance is the best.

[0070] Fig.12 These are the electrodes made of three different-structured carbonyl-containing phenazine polymers prepared in Examples 1, 6, and 7, acetylene black, and polyvinylidene fluoride in a mass ratio of 7:2:1. Their mass specific capacity comparison at different current densities is shown. It can be seen from the figure that when the selected polyketone compound is pyrene-4,5,9,10-tetrone, the mass specific capacity of the prepared electrode is the highest, and the electrochemical performance is the best.

Claims

1. A class of carbonyl-containing phenazine polymers, It is characterized in that The carbonyl-containing phenazine polymer comprises the following structure: In the above chemical formulas (I), (II) and (III), the value of n ranges from 1 to 200.

2. The method for preparing the carbonyl-containing phenazine polymer according to claim 1, It is characterized in that The preparation method comprises the following steps: under the protection of inert gas, adding a polyketone compound, 3,3,4,4-tetraaminobenzophenone and an organic solvent into a reactor, reacting the reaction mixture under reflux and heating conditions while stirring, stopping heating after sufficient reaction, cooling to room temperature, taking out, centrifuging, washing, and purifying to obtain a solid product, namely, a carbonyl-containing phenazine polymer; The polyketone compound is selected from any one of pyrene-4,5,9,10-tetraketone, cyclohexanehexaketone octahydrate, and triphenylene-2,3,6,7,10,11-hexaketone; When the polyketone compound is pyrene-4,5,9,10-tetraketone, the reaction equation is as follows: When the polyketone compound is cyclohexanone octahydrate, the reaction equation is as shown below: When the polyketone compound is triphenylene-2,3,6,7,10,11-hexaketone, the reaction equation is as shown below:

3. The preparation method according to claim 2, It is characterized in that The molar ratio of the polyketone compound to 3,3,4,4-tetraaminobenzophenone is 1:

1.

4. The preparation method according to claim 2, It is characterized in that The inert gas is nitrogen or argon.

5. The preparation method according to claim 2, It is characterized in that The organic solvent is acetic acid, the reaction is carried out at an initial temperature of 60° C. for 2 hours, the temperature is raised to 120° C. at a rate of 5° C. / min and the reaction is carried out at this temperature for 4-32 hours.

6. The preparation method according to claim 2, It is characterized in that The washing liquid used in the washing step includes hot acetic acid at 35-45°C, acetone, water at 25-30°C and ethanol in sequence.

7. The preparation method according to claim 2, It is characterized in that The purification step is: fully stirring the washed product in a hot nitric acid solution at 120-140° C., then washing with a solvent and vacuum drying at 90° C.

8. Use of the carbonyl-containing phenazine polymer according to claim 1 in preparing electrode materials for aqueous batteries.

9. The use according to claim 8, It is characterized in that The application method of the electrode material is: mixing and grinding a carbonyl-containing phenazine polymer, a conductive additive and an adhesive to obtain a slurry; coating the slurry evenly on the surface of a conductive carbon paper, drying and slicing, and obtaining the electrode material.

10. The use according to claim 8, It is characterized in that The mass ratio of the carbonyl-containing phenazine polymer, the conductive additive and the adhesive is (6-8): (3-1): (1-1).

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