3D benzoquinoline-benzonitrile electrode material, preparation method and application thereof
By preparing a three-dimensional 3D quinoxaline-benzonitrile electrode material, the problems of structural instability and low electrochemical specific capacity of aqueous potassium-ion battery anode materials were solved, achieving high electrochemical specific capacity and good cycle stability, thus improving the electrochemical performance of the battery.
Patent Information
- Application Number
- CN202311095104.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-08-29
- Publication Date
- 2026-02-13
- Estimated Expiration
- 2043-08-29
AI Technical Summary
Existing aqueous potassium-ion battery anode materials suffer from structural instability and low electrochemical specific capacity, which limits their application range.
A 3D quinoxaline-benzonitrile electrode material with a three-dimensional structure was prepared by dehydration condensation of pteridine and 1,2-diaminopeptide nitrile in polyphosphoric acid and N-methyl-2-pyrrolidone, forming a π-conjugated system with C≡N and C=N groups. This material serves as the negative electrode material for aqueous potassium-ion batteries, ensuring the exposure of active sites and structural stability.
It improves the electrochemical specific capacity and cycle stability of aqueous potassium-ion batteries, ensures rapid electron and ion transport efficiency, and enhances the cycle life and electrochemical performance of the batteries.
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Figure CN117126165B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to a 3D quinoline-benzonitrile electrode material, and also relates to a preparation method of the 3D quinoline-benzonitrile electrode material and application thereof in a water-based potassium ion battery. BACKGROUND
[0002] Rechargeable metal lithium ion batteries have been widely used in portable electronic products and electric vehicles. However, metal lithium ion batteries still have a large number of problems, such as high cost, low safety, etc., which limit their application range. The rechargeable water-based battery using aqueous electrolyte can greatly reduce the above concerns. In the past few years, such batteries have undergone rapid development. As an ideal negative electrode of water-based batteries, metal potassium has a low redox potential (-2.93 V vs. S.H.E.), which is close to Li + / K (-2.93 V) is close to Li + / Li (-3.04 V compared with S.H.E.) is lower than Na + / Na (-2.71 V compared with S.H.E.), which indicates that potassium ion batteries can simultaneously obtain higher battery voltage and energy density. At present, the research on negative electrode materials of water-based potassium ion batteries mainly focuses on inorganic compounds such as metal oxides, prussian blue analogues, etc. However, such materials are scarce in natural resources. In contrast, organic electrode materials have the advantages of low cost, environmental friendliness and adjustable electrochemical performance. The existing organic electrode materials have the problems of poor cycle stability and low electrochemical specific capacity due to unstable structure. SUMMARY
[0003] The purpose of the present application is to provide a 3D quinoline-benzonitrile electrode material with stable structure and high electrochemical specific capacity, and another purpose of the present application is to provide a preparation method of the 3D quinoline-benzonitrile electrode material and application thereof in a water-based potassium ion battery.
[0004] Technical solution: The 3D quinoline-benzonitrile electrode material provided by the present application has the following structural formula:
[0005]
[0006] The molecular structure of the 3D quinoline-benzonitrile electrode material of the present application is a three-dimensional structure, which is beneficial to the embedding / extraction of K + in the reaction process on one hand, and can completely expose the active sites (C≡N and C=N groups), thereby effectively improving the electrochemical specific capacity of the electrode material; at the same time, the three-dimensional structure has a π conjugated system and a large molecular weight, which can effectively improve the cycle stability of the negative electrode material in the reaction process.
[0007] The preparation method of the 3D quinoxaline-benzonitrile electrode material comprises the following steps:
[0008] (1) In an argon-filled glove box, N-methyl-2-pyrrolidone (as a reaction solvent) is mixed with polyphosphoric acid (as a reaction catalyst) to obtain a mixed solution; then, the mixture is stirred uniformly, and butterfly ketone and 1,2-diamino peptide nitrile are added to the mixed solution, and the mixture is refluxed at 100-105 DEG C for 10-12 hours;
[0009] (2) The mixture obtained in step (1) is centrifugally washed with methanol and deionized water in sequence, and the obtained solid product is freeze-dried;
[0010] (3) The freeze-dried solid is treated with a hydrochloric acid solution, and then centrifugally washed with deionized water, and vacuum freeze-dried to obtain the target product, i.e., the 3D quinoxaline-benzonitrile electrode material.
[0011] In step (1), the volume ratio of N-methyl-2-pyrrolidone to polyphosphoric acid is 25:1.
[0012] In step (1), the mass ratio of butterfly ketone to 1,2-diamino peptide nitrile is 166-169:627-629.
[0013] In step (2), the freeze-drying temperature is -97 DEG C, and the freeze-drying time is 5.5-6 hours.
[0014] In step (3), the concentration of the hydrochloric acid solution is 0.1 M, and the purpose of the hydrochloric acid solution treatment is to remove impurities and to perform an antioxidant treatment.
[0015] In step (3), the vacuum degree of the vacuum freeze-drying is 40-50 P, the temperature is -97 DEG C, and the vacuum freeze-drying time is 9.5-10 hours. The two-time freeze-drying is performed to improve the drying quality, and the two-time freeze-drying can better eliminate the possibility of residual moisture and ice crystals, thereby improving the drying quality and helping to reduce or avoid the occurrence of structure collapse and deformation during the drying process.
[0016] The 3D quinoxaline-benzonitrile electrode material is obtained by dehydration condensation of butterfly ketone and 1,2-diamino peptide nitrile in polyphosphoric acid and N-methyl-2-pyrrolidone. The 3D quinoxaline-benzonitrile electrode material is used as a negative electrode material of a water-based potassium ion battery, the fully exposed C≡N and C=N groups in the 3D quinoxaline-benzonitrile electrode material serve as redox active sites to realize reversible storage of K + , improve the electrochemical specific capacity of the electrode material, and have excellent structural stability; the π conjugated system formed in the molecule can effectively inhibit the dissolution of the electrode material, and the electrode material still has fast electron transfer and ion transport efficiency in the electrochemical reaction, thereby having excellent electrochemical performance.
[0017] The application of the above 3D quinoline-benzonitrile electrode material in a water-based potassium ion battery is as follows: 3D quinoline-benzonitrile organic electrode material, conductive carbon material, crosslinking agent and organic solvent are ground into a well-dispersed slurry in a marver, the slurry is uniformly coated on carbon paper, vacuum drying is performed at 60-70 DEG C, the drying time is 22-26 h, and an electrode sheet is prepared; and the electrode sheet is used as the anode of the water-based potassium ion battery.
[0018] The conductive carbon material is carbon nanotubes; the crosslinking agent is polyvinylidene fluoride (PVDF); the organic solvent is N-methyl-2-pyrrolidone (NMP); and the mass ratio of the 3D quinoline-benzonitrile organic electrode material, the carbon nanotubes and the polyvinylidene fluoride is 70:20:10.
[0019] The 3D quinoline-benzonitrile compound is used as the anode material of the water-based potassium ion battery, the C≡N and C=N groups in the 3D quinoline-benzonitrile compound can improve the K + reaction kinetics and redox potential, and the two active sites can simultaneously store and coordinate K + , thereby improving the electrochemical capacity and structural stability of the electrode material (avoiding structural collapse). Since the ionic radius of K + is large, structural distortion of the electrode material is easily caused in the reaction process, thereby affecting the cycle life of the electrode. The pi conjugated system in the 3D quinoline-benzonitrile compound provides a stable composite structure, and the three-dimensional structure (expanded conjugation and molecular weight) can effectively inhibit the dissolution of the active material in the reaction process, and can ensure fast electron transfer and ion transmission in the electrochemical reaction, thereby being beneficial to improving the rate and cycle life of the water-based potassium ion battery.
[0020] Advantages: Compared with the prior art, the method of the application can prepare the 3D quinoline-benzonitrile compound with a three-dimensional structure, and the compound shows good cycle stability and high cycle specific capacity when applied to the water-based potassium ion battery as the anode material, and the electrochemical performance is excellent. BRIEF DESCRIPTION OF DRAWINGS
[0021] Figure 1 X-ray diffraction patterns of quinoline-benzonitrile compounds obtained at synthesis temperatures of 80 DEG C, 100 DEG C and 120 DEG C, respectively;
[0022] Figure 2 NMR charts of quinoline-benzonitrile compounds obtained at synthesis temperatures of 80 DEG C, 100 DEG C and 120 DEG C, respectively;
[0023] Figure 3Electrochemical performance chart of quinoxaline-benzonitrile compound obtained at synthesis temperature 80℃, 100℃, 120℃, respectively;
[0024] Figure 4 Constant current charge-discharge curve chart of water-based potassium ion battery of 3D quinoxaline-benzonitrile electrode material obtained in Example 1 under 70%, 60% and 50% active material coating;
[0025] Figure 5 Electrochemical performance chart of water-based potassium ion battery of 3D quinoxaline-benzonitrile electrode material obtained in Example 1 at 2, 4, 8 Ag -1 Current density at room temperature. DETAILED DESCRIPTION
[0026] Example 1
[0027] The preparation method of the 3D quinoxaline-benzonitrile electrode material of the application comprises the following steps:
[0028] (1) In an argon-filled glove box, 25 mL of N-methyl-2-pyrrolidone is mixed with 1 mL of polyphosphoric acid and stirred for 25 minutes to obtain a mixed solution, 166 mg of chrysin (purchased from Jilin Zhongke Research Technology Co., Ltd.) and 627 mg of 1,2-diaminophthalonitrile are weighed and added to the mixed solution and stirred uniformly, and then stirred and refluxed at 100℃ for 12 hours;
[0029] The 1,2-diaminophthalonitrile is prepared by the following method: 87.1 mMol of 4,5-dibromo-1,2-diaminobenzene, 262.5 mMol of CuCN and 240 mL of anhydrous DMF (dimethylformamide) are heated to 130℃ under N2 atmosphere for 48 hours, and then the reaction mixture is dispersed in a mixture of dichloromethane (1 liter) and acetic acid (100 mL); extracted with EDTA-2Na solution (300 mL of dichloromethane containing 8 g of EDTA-2Na), and extracted twice to remove residual Cu 2+ ; the aqueous phase is separated and extracted with 500 mL of dichloromethane, and the organic phases are combined and filtered through a fine fritted funnel; the organic solution is collected and evaporated to obtain a white solid;
[0030] (2) The mixture obtained in step (1) is washed with methanol and deionized water by centrifugation in sequence until the washing liquid is colorless, and the obtained solid product is freeze-dried at -97℃ for 6 hours; the obtained solid is treated with 0.1 M hydrochloric acid solution for 30 minutes, and then washed with deionized water by centrifugation, and vacuum freeze-dried at a vacuum degree of 40-50 P for 10 hours, with the freeze-drying temperature being -97℃, to obtain the target product with stable structure, i.e. the 3D quinoxaline-benzonitrile compound.
[0031] Figure 1XRD patterns of quinoxaline-benzonitrile compounds obtained at synthesis temperatures of 80℃, 100℃ and 120℃, respectively; through Figure 1 It can be seen that the quinoxaline-benzonitrile synthesized at 80℃ and 120℃ has poor crystallinity, which may be due to the excessively high or low Gibbs free energy during the reaction, affecting the reaction rate, while the 3D quinoxaline-benzonitrile synthesized at 100℃ has better crystallinity, and the (001) and (110) crystal planes are clearly visible.
[0032] Figure 2 NMR patterns of quinoxaline-benzonitrile compounds obtained at synthesis temperatures of 80℃, 100℃ and 120℃, respectively. The peak at 54ppm is a characteristic peak of the carbon atom of triptycene, and the peak at 67ppm is a carbon atom of benzonitrile. From Figure 2 It can be seen that the quinoxaline-benzonitrile synthesized at 80℃ and 120℃ lacks a characteristic peak around 54ppm, while only the quinoxaline-benzonitrile synthesized at 100℃ has a characteristic peak of the carbon atom of triptycene, indicating that only the quinoxaline-benzonitrile synthesized at this condition can maintain the original triptycene structure, and further form a three-dimensional quinoxaline-benzonitrile structure.
[0033] Figure 3 CV patterns of quinoxaline-benzonitrile compounds obtained at synthesis temperatures of 80℃, 100℃ and 120℃, respectively, through Figure 3 It can be seen that the integral area of the CV curve of the quinoxaline-benzonitrile synthesized at 80℃ and 120℃ is significantly smaller than that of the 3D quinoxaline-benzonitrile synthesized at 100℃, indicating that the crystallinity and three-dimensional structure of the quinoxaline-benzonitrile affect its electrochemical performance. Through experiments, it is found that the 3D quinoxaline-benzonitrile synthesized at 100℃ has good crystallinity and a three-dimensional structure, thus having good electrochemical performance.
[0034] Example 2
[0035] The 3D quinoxaline-benzonitrile electrode material obtained in Example 1, carbon nanotubes and polyvinylidene fluoride were mixed in a mass ratio of 70:20:10 (70mg, 20mg and 10mg, respectively) with N-methyl pyrrolidone (NMP, 1mL) added, and ground into a well-dispersed slurry in a marquis mortar. The slurry was evenly coated on carbon paper, and vacuum dried at 70℃ for 24h to obtain a working electrode (polar piece).
[0036] The prepared polar piece was used as the negative electrode, Ni(OH)2 was used as the positive electrode, a glass fiber separator was used to separate the two electrodes, and a 10M KOH solution was used as the electrolyte to prepare and assemble a soft pack battery. The test voltage range was 0V-1.5V.
[0037] Figure 4 The graph shows the constant current charge-discharge curves of an aqueous potassium-ion battery using the 3D quinoxaline-benzonitrile electrode material obtained in Example 1 at different active material ratios of 70%, 60%, and 50%. Figure 4 As the proportion of active material increases, the electrode capacity further expands, indicating that the capacity of a single electrode is mainly provided by the active material quinoxaline-benzonitrile. Furthermore, given sufficient space, the three-dimensional structure of quinoxaline-benzonitrile can expose more active sites to interact with K+. + This combination increases the capacity of the electrode.
[0038] 3D quinoxaline-benzonitrile exhibits high redox activity and a wide plateau voltage. This suggests that the fully exposed C≡N and C=N active groups in the 3D quinoxaline-benzonitrile electrode material improve the electrochemical specific capacity and structural stability of the electrode material. Moreover, under certain conditions, the electrode capacity increases with the increase of the active material mass.
[0039] Figure 5 The 3D quinoxaline-benzonitrile electrode material obtained in Example 1 was used in 2, 4, and 8 Ag... -1 Constant current charge-discharge curves of a room-temperature aqueous potassium-ion battery (the battery prepared in Example 2) at current density. Figure 5 As can be observed, the constant current charge-discharge curve of this battery exhibits charge-discharge characteristics within the adopted voltage window, and a distinct voltage plateau is evident. This analysis indicates that at 2Ag... -1 At the specified current density, the specific capacity of the 3D quinoxaline-benzonitrile electrode material is approximately 132 mAh g after 100 cycles. -1 Its excellent capacity performance demonstrates the high redox activity of the fully exposed C≡N and C=N groups. Furthermore, the battery exhibits a distinct voltage plateau during constant current charge-discharge, showcasing excellent charge storage performance. This is due to the high current density (4Ag) at which it can effectively store charge. -1 8Ag -1 The battery has a slow redox rate, which does not have enough time for pseudocapacitive behavior to occur, resulting in a large number of ions accumulating at the solid-liquid interface to form an SEI film, thereby hindering further redox reactions.
[0040] The C≡N and C=N active groups in 3D quinoxaline-benzonitrile compounds can simultaneously store and coordinate K. + Furthermore, the three-dimensional molecular structure allows for full exposure of active groups, improving the utilization rate of active groups and thus increasing the electrochemical specific capacity of the electrode material. At the same time, the π-conjugated system in the 3D quinoxaline-benzonitrile compound can bring higher cycle stability (structural stability) and conductivity, making it a good electrochemical material for aqueous potassium-ion batteries.
Claims
1. A 3D quinoxaline-benzonitrile electrode material, characterized in that, Its structural formula is:
2. The method for preparing the 3D quinoxaline-benzonitrile electrode material according to claim 1, characterized in that, Includes the following steps: (1) In a glove box filled with argon, N-methyl-2-pyrrolidone and polyphosphoric acid were mixed to obtain a mixed solution; pteridone and 1,2-diaminopeptide nitrile were added to the above mixed solution and stirred evenly, and refluxed at 100-105°C for 10-12 h. (2) The mixture obtained in step (1) was washed by centrifugation with methanol and deionized water in sequence, and the resulting solid product was freeze-dried. (3) Treat the freeze-dried solid with hydrochloric acid solution, then wash it with deionized water by centrifugation, and freeze-dry it under vacuum to obtain the target product.
3. The method for preparing the 3D quinoxaline-benzonitrile electrode material according to claim 2, characterized in that: In step (1), the volume ratio of N-methyl-2-pyrrolidone and polyphosphoric acid is 25-28:
1.
4. The method for preparing the 3D quinoxaline-benzonitrile electrode material according to claim 2, characterized in that: In step (1), the mass ratio of pteridone to 1,2-diaminopeptide nitrile is 166-169:627-629.
5. The method for preparing the 3D quinoxaline-benzonitrile electrode material according to claim 2, characterized in that: In step (2), the freeze-drying temperature is -97℃ and the time is 5.5 to 6 hours.
6. The method for preparing the 3D quinoxaline-benzonitrile electrode material according to claim 2, characterized in that: In step (3), the concentration of the hydrochloric acid solution is 0.1–0.12 M.
7. The method for preparing the 3D quinoxaline-benzonitrile electrode material according to claim 2, characterized in that: In step (3), the vacuum degree of vacuum freeze drying is 40-50P, the temperature is -97℃, and the time is 9.5-10 hours.
8. The application of the 3D quinoxaline-benzonitrile electrode material according to claim 1 in an aqueous potassium-ion battery, characterized in that, Specifically, the process involves mixing 3D quinoxaline-benzonitrile organic electrode material, conductive carbon material, crosslinking agent, and organic solvent to obtain a slurry. The slurry is then uniformly coated onto carbon paper and vacuum-dried at 60–70°C to produce an electrode sheet. The fabricated electrode is used as the negative electrode in an aqueous potassium-ion battery.
9. The application of the 3D quinoxaline-benzonitrile electrode material according to claim 8 in an aqueous potassium-ion battery, characterized in that: The conductive carbon material is carbon nanotubes; the crosslinking agent is polyvinylidene fluoride; and the organic solvent is N-methyl-2-pyrrolidone.
10. The application of the 3D quinoxaline-benzonitrile electrode material according to claim 8 in an aqueous potassium-ion battery, characterized in that: The mass ratio of 3D quinoxaline-benzonitrile organic electrode material, carbon nanotubes, and polyvinylidene fluoride is 50–70:20:10.