Two-dimensional acetylene-rich carbon frame fast-charging negative electrode material and preparation method and application thereof

Abstract

The invention belongs to the technical field of electrochemistry, and relates to a two-dimensional acetylene-rich carbon frame fast-charging negative electrode material and a preparation method and application thereof. The negative electrode material is prepared by respectively dissolving two monomers in an upper layer and a lower layer of mutually insoluble solvents and carrying out Sonogashira coupling polymerization at an interface, the two monomers are bromine-containing organic lithium and 1, 4-diacetylene benzene. The two monomers can also be added into an organic solvent, and corresponding products can be obtained through an oil bath heating reaction. The highly ordered structure of the material can significantly improve the transmission kinetics of lithium ions. In addition, the introduction of the carboxyl lithium group can optimize the electronic structure of the material, so that the electrode interface desolvation process and SEI interface film components are regulated and controlled, and excellent fast charging performance is shown. The invention provides a high-performance electrode material and an innovative preparation method for the fast-charging lithium ion battery.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of electrochemistry, and relates to a two-dimensional acetylene-rich carbon framework fast-charging negative electrode material and a preparation method and application thereof. BACKGROUND

[0002] The increasing demand for portable electronic devices and electric vehicles has driven the rapid development of fast-charging battery technology. Traditional battery materials often face the problem of slow mass transfer kinetics due to insufficient porosity and ion channels, which limits the improvement of battery fast-charging performance. Two-dimensional (2D) conjugated carbon-based frameworks (CCFs) have an extended π-conjugated system and sp / sp 2 hybrid carbon structure, which exhibits excellent electronic conductivity, high specific surface area, and unique pore structure, making it a potential candidate for high-performance fast-charging electrode materials. In particular, two-dimensional porous conjugated carbon-based frameworks rich in acetylene groups have ideal channels perpendicular to the molecular plane, which can promote efficient charge transport and rapid ion diffusion, perfectly matching the key elements for achieving excellent fast-charging performance. For example, graphdiyne composed of sp and sp 2 hybrid carbon atoms has a large specific surface area, triangular pores, adjustable pore size, and highly ordered ion transport channels. These characteristics enable ions to diffuse through large triangular pores, significantly improving ion transport kinetics. Despite these advantages, it is still a challenge to prepare large-area, high-crystalline two-dimensional conjugated carbon-based frameworks and reproduce the excellent transport performance of individual channels in large-scale practical applications. This is mainly because it is difficult to achieve the ordered and uniform arrangement or stacking of such materials during thin film preparation, while maintaining their unique structure and performance.

[0003] Currently, researchers have used various strategies to prepare large-area two-dimensional carbon-based thin films, including chemical vapor deposition, interfacial synthesis, solution-phase synthesis, and mechanical exfoliation. However, these methods have limited ability to control material defects and crystallinity, which can lead to undefined framework structures. In particular, for synthesis methods based on solutions and interfaces, the random motion of molecules and the free rotation of chemical bonds cannot trigger in-plane coupling or polymerization reactions, which can cause the framework to grow randomly out of plane, ultimately forming a three-dimensional (3D) disordered structure rather than a two-dimensional ordered crystalline thin film. This disordered structure and defects can negatively affect the physical, chemical, and electronic properties of the material, significantly reducing the transport efficiency of charges and ions. In addition, from the perspective of molecular design, precise functionalization of two-dimensional conjugated carbon-based frameworks (CCFs) is expected to impart unexpected properties to the material and improve its performance in energy storage, catalysis, and separation. However, due to the lack of effective synthesis pathways, it is still extremely rare to achieve precise functionalization of large-area, high-quality two-dimensional conjugated carbon-based frameworks. SUMMARY

[0004] To solve the above problems, the application provides a two-dimensional acetylene-rich carbon framework fast-charging negative electrode material and a preparation method and application thereof. The application proposes a "molecular locking-weaving" strategy, which can inhibit the random movement of molecules and the free rotation of chemical bonds at a liquid / liquid interface that is not miscible with each other, thereby preparing a carboxyl lithium-modified two-dimensional crystalline acetylene-rich carbon framework fast-charging negative electrode material with a large area, high crystallinity and intrinsic mesoporous structure, constructing an ordered lithium ion transmission channel and significantly improving the diffusion rate of lithium ions.

[0005] The application provides the following technical scheme: a two-dimensional acetylene-rich carbon framework fast-charging negative electrode material, which is prepared by dissolving two monomers in two layers of mutually immiscible solvents from top to bottom and performing Sonogashira coupling polymerization at the interface; or adding the two monomers to an organic solvent and obtaining a corresponding product through oil bath heating reaction; the two monomers are bromine-containing organolithium and 1,4-diethynylbenzene.

[0006] Further, the application provides a preparation method of the two-dimensional acetylene-rich carbon framework fast-charging negative electrode material, which comprises the following steps: (1) dissolving a bromine-containing monomer in ethanol, adding excessive LiOH·H2O and mixing and stirring, and then washing, drying and obtaining a bromine-containing organolithium powder; (2) mixing the bromine-containing organolithium powder obtained in step (1) with a catalyst, wherein the catalyst is Pd(PPh3)4 and CuI, and the amount of Pd(PPh3)4 and CuI is 5-10% and 10-15% of the mass of the bromine-containing organolithium, respectively; (3) reacting 1,4-diethynylbenzene with the mixture in step (2), wherein the molar ratio of 1,4-diethynylbenzene to the bromine-containing organolithium is (2.4-10):1; the reaction is performed by one of the following two schemes: Scheme A: dissolving the bromine-containing organolithium powder and the catalyst in water to form an aqueous phase, dissolving 1,4-diethynylbenzene in an organic solvent to form an organic phase, adding the aqueous phase to the upper layer of the organic phase, and reacting at the interface for 2-5 days; or Scheme B: dissolving the bromine-containing organolithium powder and the catalyst in a mixed organic solvent, then dissolving 1,4-diethynylbenzene in the same mixed organic solvent, and heating in an oil bath for 2-5 days, and the heating temperature is 90-100℃; (4) washing and purifying the material obtained by reaction to obtain the final product.

[0007] Preferably, in step (1), the bromine-containing monomer is selected from any one of tetrabromophthalic acid, tetrabromobenzene, tetrabromophenol and tribromophenol.

[0008] Preferably, in step (3), the organic solvent is selected from any one or several of dichloromethane, tetrahydrofuran, N,N-dimethylformamide and toluene.

[0009] Preferably, in step (4), the washing reagent is selected from one or more of deionized water, anhydrous ethanol, dichloromethane, methanol, tetrahydrofuran, N,N-dimethylformamide, chloroform, acetone.

[0010] Further, the application also provides application of the two-dimensional alkyne-rich carbon framework fast-charging negative electrode material in preparation of an alkali metal ion battery.

[0011] Further, the application also provides an alkali metal ion battery, which comprises the two-dimensional alkyne-rich carbon framework fast-charging negative electrode material, an electrolyte, lithium metal and a positive electrode material.

[0012] Preferably, the lithium metal is provided by any one of the following lithium salts: lithium hexafluorophosphate, lithium perchlorate, lithium bisfluorosulfonylimide, lithium bis-trifluoromethylsulfonylimide.

[0013] Preferably, the electrolyte is selected from one or more of ethylene carbonate, dimethyl carbonate, fluoroethylene carbonate, propylene carbonate, diethyl carbonate.

[0014] Preferably, the positive electrode material is selected from any one of ternary lithium ion battery positive electrode materials, lithium cobaltate, lithium iron phosphate, lithium-rich manganese-based materials.

[0015] The beneficial effects of the application relative to the prior art are: (1) In the application, the two-dimensional alkyne-rich carbon framework fast-charging negative electrode material is prepared by using an interfacial synthesis method, two monomers are dissolved in two layers of mutually insoluble solvents respectively, and coupling polymerization is carried out at the interface. Alternatively, the two monomers can be added to an organic solvent, and the corresponding product can be obtained by oil bath heating reaction. The prepared two-dimensional alkyne-rich carbon framework fast-charging negative electrode material has high crystallinity and can be prepared in a large area, and the preparation method is simple and efficient; (2) The prepared two-dimensional alkyne-rich carbon framework fast-charging negative electrode material can simultaneously control the ion transmission channel inside the active material, the electrode interface desolvation process and the SEI interface film composition, thereby exhibiting excellent fast-charging performance. The material has the following characteristics: (a) high crystallinity ensures the order of the internal structure of the material; (b) the large interlayer spacing and the AB stacking structure promote the ion transmission dynamics inside the material; (c) the carboxyl lithium groups on the material skeleton can promote the delocalization of electrons to improve the electrical conductivity, and the abundant electrons can improve the surface potential of the material and strengthen the adsorption of lithium ions, promoting the desolvation of lithium ions; (d) the strong polarity of the carboxyl lithium group can transfer more electrons from the substrate to the electrolyte, thereby promoting the decomposition of PF6 - to generate an SEI film mainly composed of LiF; (3) The prepared carboxyl lithium modified two-dimensional rich-alkyne carbon framework fast-charging negative electrode material has excellent fast-charging performance in the field of lithium ion batteries. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 A preparation method principle schematic diagram of the two-dimensional rich-alkyne carbon framework fast-charging negative electrode material is provided in the present application. Figure 2 A transmission electron microscope graph of the two-dimensional rich-alkyne carbon framework fast-charging negative electrode material prepared in the present application is provided. Figure 3 An atomic force microscope graph of the two-dimensional rich-alkyne carbon framework fast-charging negative electrode material prepared in the present application is provided. Figure 4 An X-ray photoelectron spectrograph of C 1s of the two-dimensional rich-alkyne carbon framework fast-charging negative electrode material prepared in the present application is provided. Figure 5 A Raman spectrograph of the two-dimensional rich-alkyne carbon framework fast-charging negative electrode material prepared in the present application is provided. Figure 6 Nitrogen adsorption-desorption isotherm and pore size distribution graph of the two-dimensional rich-alkyne carbon framework fast-charging negative electrode material prepared in the present application is provided. Figure 7 A fine X-ray diffraction graph of the two-dimensional rich-alkyne carbon framework fast-charging negative electrode material prepared in the present application is provided. Figure 8 A high-resolution transmission electron microscope graph of the two-dimensional rich-alkyne carbon framework fast-charging negative electrode material prepared in the present application is provided. Figure 9 Rate performance of the two-dimensional rich-alkyne carbon framework fast-charging negative electrode material prepared in the present application in a lithium ion battery is provided. Figure 10 Cycle performance of the two-dimensional rich-alkyne carbon framework fast-charging negative electrode material prepared in the present application in a lithium ion battery under the condition of 5 A g -1 Figure 11 Fast-charging performance of the two-dimensional rich-alkyne carbon framework fast-charging negative electrode material prepared in the present application in a lithium ion full battery under the condition of 6C with LiNi 0.8 Co 0.1 Mn 0.1 O2(NCM811) ternary material as a positive electrode is provided. Figure 12 Cycle performance of the two-dimensional rich-alkyne carbon framework fast-charging negative electrode material prepared in the present application in a lithium ion battery under the condition of a single-mole ratio of 4:1 is provided. Figure 13 A transmission electron microscope graph of the material obtained by using tetrabromophenol as a bromine-containing monomer for the two-dimensional rich-alkyne carbon framework fast-charging negative electrode material prepared in the present application is provided. Figure 14 ​The two-dimensional acetylene-rich carbon framework fast-charging anode material prepared for this invention is obtained by oil bath method, and the S-scanning electron microscope image of the material is shown. Figure 15 The two-dimensional acetylene-rich carbon framework fast-charging anode material prepared in this invention was used in a lithium-ion battery at 20 A g. -1 Cyclic performance under certain conditions; Figure 16 The fast-charging performance of the two-dimensional acetylene-rich carbon framework fast-charging anode material prepared by this invention, with NCM811 ternary material as the cathode, under 20C conditions in a lithium-ion full battery. Figure 17 The fast-charging performance of the two-dimensional acetylene-rich carbon framework anode material prepared by this invention, with NCM811 ternary material as the cathode, under 4C conditions in lithium-ion soft-pack batteries. Detailed Implementation

[0017] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments, but it is not limited thereto. Any modifications or equivalent substitutions to the technical solution of the present invention that do not depart from the spirit and scope of the technical solution of the present invention should be covered within the protection scope of the present invention.

[0018] Example 1: The two-dimensional ytylene-rich carbon framework fast-charging anode material of this example was prepared using the following method: 1 g of tetrabromoterephthalic acid was dissolved in anhydrous ethanol, and 240 mg of lithium hydroxide was added. The mixture was stirred for 24 h. The resulting white powder was centrifuged, washed, and dried to obtain lithium tetrabromoterephthalate. 10 ml of a 0.06 mM solution of 1,4-diethynylbenzene in dichloromethane was placed in a glass bottle. Then, 5 ml of deionized water was slowly added to form a two-phase interface. 10 ml of a 0.025 mM aqueous solution of lithium tetrabromoterephthalate was taken, and 3.5 mg of Pd(PPh3)4 and 1 mg of CuI were added. After mixing and stirring thoroughly, the solution was added to the aqueous phase. After standing at room temperature for 48 h, a brown film was obtained at the two-phase interface. The upper aqueous phase was washed three times with 1 M dilute hydrochloric acid and deionized water, and the lower organic phase was washed three times with dichloromethane. Finally, the liquids of both phases were removed, and the film was placed in anhydrous ethanol. Figure 1 As shown.

[0019] In this embodiment, the prepared film exhibits an ultrathin state, such as... Figure 2 and Figure 3 As shown, the thickness is only about 3.3 nm. From Figure 4 The X-ray photoelectron spectrum shown indicates that the bonding mechanism in its structure is highly consistent with its chemical structure. For example... Figure 5 As shown, Raman spectroscopy characterization revealed a low D / G peak ratio in the thin film, indicating fewer internal defects.Figure 6 As shown, its pore structure was characterized by nitrogen adsorption-desorption curves, revealing that its internal mesoporous structure facilitates rapid lithium-ion transport. Figure 7 As shown, X-ray diffraction results indicate that the carboxyl-lithium-modified two-dimensional crystalline alkyne-rich carbon framework fast-charging anode material possesses high crystallinity, which helps ensure the orderliness of its internal structure, thus further enhancing its fast-charging chemical performance. Figure 8 As shown, its structure was further characterized by high-resolution transmission electron microscopy, which further proved its high degree of crystallinity.

[0020] Active material, Super P (conductive carbon black), and PVDF (polyvinylidene fluoride) were mixed in a mass ratio of 8:1:1 to form a slurry, and electrodes were prepared. A CR 2032 coin cell was fabricated using 1 M LiPF6+EC / DEC / DMC (1:1:1) as the electrolyte and lithium metal as the negative electrode. Electrochemical performance was tested and compared with that of a two-dimensional alkyne-rich carbon frame material (ACF) without carboxyl-modified lithium. Its rate performance and high-rate long-cycle performance are as follows: Figure 9 and Figure 10 As shown, the prepared two-dimensional crystalline alkyne-rich carbon framework fast-charging anode material exhibits excellent fast-charging chemical performance in lithium-ion half-cells. LiNi0 0.8 Co 0.1 Mn 0.1 The full battery assembled with an O2 ternary cathode and a two-dimensional crystalline alkyne-rich carbon framework fast-charging anode exhibits excellent fast-charging performance, such as... Figure 11 As shown.

[0021] Example 2: In this example, by changing the monomer feed ratio, a series of carboxyl-modified two-dimensional crystalline alkyne-rich carbon framework fast-charging anode materials with a 1,4-diethynylbenzene / lithium tetrabromoterephthalate molar ratio of 4:1, 6:1, 8:1, and 10:1 were prepared, and the electrochemical performance of the lithium-ion battery was tested. Other processing methods are similar to those in Example 1. For example, a two-dimensional alkyne-rich carbon framework fast-charging anode material with a 1,4-diethynylbenzene / lithium tetrabromoterephthalate molar ratio of 4:1 was prepared, and the electrochemical performance of the lithium-ion battery was tested. The test results are as follows: Figure 12 As shown, the assembled half-cell operates at 5 A g. -1 It exhibits excellent cycling stability at current densities.

[0022] Example 3: This example changes the type of bromine-containing monomer, using tetrabromobenzene, tetrabromophenol, tribromophenol, etc., to prepare fast-charging negative electrode materials containing different types of groups. For example, tetrabromophenol is used as the bromine-containing monomer, and other processing methods are the same as in Example 1. The transmission electron microscope image of the prepared fast-charging negative electrode material is shown below. Figure 13 As shown.

[0023] In other embodiments of the present invention, tetrabromobenzene and tribromophenol are used as monomers. The preparation method is consistent with that in Example 1 in principle, which is carried out by the Sonogashira coupling reaction, and can also prepare corresponding products containing different groups.

[0024] Example 4: This example uses the oil bath method (Scheme B) to prepare a carboxyl lithium-modified two-dimensional crystalline acetylene-rich carbon framework fast-charging anode material, with the monomer feed ratio being the same as in Example 1. The scanning electron microscope image of the prepared fast-charging anode material is shown below. Figure 14 As shown.

[0025] Example 5: This example utilizes the negative electrode material prepared in Example 1, assembling a battery with the battery composition unchanged, and varying the battery's test rate to study the electrochemical performance of the carboxyl lithium-modified two-dimensional crystalline alkyne-rich carbon framework fast-charging negative electrode material at high current densities. For example, the battery performance at 20 A g was studied. -1 Cyclic stability under high current density, test results are as follows: Figure 15 As shown, the assembled battery at 20 A g -1 It exhibits excellent cycling stability at high current densities.

[0026] Example 6: This example uses the negative electrode material prepared in Example 1 as the negative electrode and NCM811 ternary material as the positive electrode. A full cell is assembled with the battery composition kept constant. The test rate of the full cell is varied to study the electrochemical performance of the carboxyl lithium-modified two-dimensional crystalline alkyne-rich carbon framework fast-charging negative electrode material at high rates. For example, the cycle stability of the full cell at a high rate of 20 C is studied, and the test results are as follows: Figure 16 As shown, the assembled full cell exhibits excellent cycle stability at a high rate of 20C.

[0027] Example 7: This example uses the negative electrode material prepared in Example 1 as the negative electrode and NCM811 as the positive electrode, changing the type of assembled battery to study the electrochemical performance of the two-dimensional crystalline alkyne-rich carbon framework fast-charging negative electrode material in different types of batteries. For example, an NCM811 soft-pack lithium-ion battery was assembled, and the electrochemical performance of the lithium-ion battery was tested. Figure 17 As shown, the assembled pouch battery exhibits excellent fast charging performance.

[0028] The two-dimensional acetylene-rich carbon framework fast-charging anode material provided by this invention has excellent fast-charging performance and ultra-long cycle life, and is suitable for high energy density and high power density lithium-ion batteries, with broad market application prospects.

[0029] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A two-dimensional hyperacetylenic carbon framework fast-charging negative electrode material, characterized in that: The negative electrode material is prepared by dissolving two monomers in two layers of mutually insoluble solvents respectively, and performing Sonogashira coupling polymerization at the interface; or by adding the two monomers into an organic solvent, and performing oil bath heating reaction to obtain the corresponding product; the two monomers are bromine-containing organolithium and 1,4-diethynylbenzene.

2. A method for preparing the two-dimensional hyperacetylenic carbon framework fast-charging negative electrode material of claim 1, characterized in that, The method comprises the following steps: (1) dissolving the bromine-containing monomer in ethanol, adding excess LiOH·H2O, mixing and stirring, washing, drying to obtain bromine-containing organolithium powder; (2) mixing the bromine-containing organolithium powder obtained in step (1) with a catalyst, wherein the catalyst is Pd(PPh3)4 and CuI, and the amount of Pd(PPh3)4 and CuI is 5-10% and 10-15% of the mass of the bromine-containing organolithium respectively; (3) reacting 1,4-diethynylbenzene with the mixture of step (2), wherein the molar ratio of 1,4-diethynylbenzene to bromine-containing organolithium is (2.4-10):1; the reaction is performed by one of the following two schemes: Scheme A: dissolving the bromine-containing organolithium powder and the catalyst in water to form an aqueous phase, dissolving 1,4-diethynylbenzene in an organic solvent to form an organic phase, adding the aqueous phase to the upper layer of the organic phase, and reacting at the interface for 2-5 days; or Scheme B: dissolving the bromine-containing organolithium powder and the catalyst in a mixed organic solvent, then dissolving 1,4-diethynylbenzene in the same mixed organic solvent, heating in an oil bath for 2-5 days, and the heating temperature is 90-100°C; (4) washing and purifying the material obtained by reaction to obtain the final product.

3. The method of claim 2, wherein: In step (1), the bromine-containing monomer is selected from any one of tetrabromophthalic acid, tetrabromobenzene, tetrabromophenol, and tribromophenol.

4. The method of claim 2, wherein: In step (3), the organic solvent is selected from any one or several of dichloromethane, tetrahydrofuran, N,N-dimethylformamide, and toluene.

5. The method of claim 2, wherein: In step (4), the washing reagent is selected from one or more of deionized water, anhydrous ethanol, dichloromethane, methanol, tetrahydrofuran, N,N-dimethylformamide, chloroform, and acetone.

6. Use of the two-dimensional rich-alkyne carbon framework fast-charging negative electrode material of claim 1 in the preparation of a lithium ion battery.

7. An alkali metal battery characterized by: The battery comprises the two-dimensional rich-alkyne carbon framework fast-charging negative electrode material of claim 1, an electrolyte, lithium metal, and a positive electrode material.

8. The alkali metal battery of claim 7, wherein: The lithium metal is provided by any one of the following lithium salts: lithium hexafluorophosphate, lithium perchlorate, lithium bisfluorosulfonylimide, and lithium bis(trifluoromethylsulfonyl)imide.

9. The alkali metal battery of claim 7, wherein: The electrolyte is selected from one or more of ethylene carbonate, dimethyl carbonate, fluoroethylene carbonate, propylene carbonate, and diethyl carbonate.

10. The alkali metal battery of claim 7, wherein: The positive electrode material is selected from any one of ternary lithium ion battery positive electrode materials, lithium cobaltate, lithium iron phosphate, and lithium-rich manganese-based materials.

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