A two-dimensional rich-alkyne carbon framework fast-charging negative electrode material, a preparation method therefor, and an application thereof

Abstract

This invention belongs to the field of electrochemical technology and relates to a two-dimensional alkyne-rich carbon framework fast-charging anode material, its preparation method, and its applications. This anode material is prepared by dissolving two monomers separately in two immiscible solvents and then performing Sonogashira coupling polymerization at the interface; the two monomers are bromine-containing organolithium and 1,4-diethynylbenzene. Alternatively, the two monomers can be added to an organic solvent and reacted via an oil bath to obtain the corresponding products. The highly ordered structure of this material significantly enhances lithium-ion transport kinetics. Furthermore, the introduction of carboxyl lithium groups optimizes the electronic structure of the material, thereby regulating the desolvation process at the electrode interface and the SEI interface film composition, thus exhibiting excellent fast-charging performance. This invention provides a high-performance electrode material and an innovative preparation method for fast-charging lithium-ion batteries.

Description

Technical Field

[0001] This invention belongs to the field of electrochemical technology and relates to a two-dimensional alkyne-rich carbon framework fast-charging anode material, its preparation method, and its application. Background Technology

[0002] The growing demand for portable electronic devices and electric vehicles has driven the rapid development of fast-charging battery technology. Traditional battery materials often suffer from slow mass transfer kinetics due to insufficient porosity and ion channels, limiting the improvement of fast-charging performance. Two-dimensional (2D) conjugated carbon frameworks (CCFs) possess extended π-conjugated systems and sp / sp... 2 Hybridized carbon structures exhibit excellent electronic conductivity, high specific surface area, and unique pore structure, making them potential candidates for high-performance fast-charging electrode materials. In particular, two-dimensional porous conjugated carbon-based frameworks rich in acetylene groups possess ideal channels perpendicular to the molecular plane, which promote efficient charge transport and rapid ion diffusion, perfectly matching the key elements for achieving excellent fast-charging performance. For example, sp and sp... 2 Graphdiyne, composed of hybrid carbon atoms, possesses a large specific surface area, triangular pores, tunable pore size, and highly ordered ion transport channels. These properties allow ions to diffuse out-of-plane through large triangular pores, significantly enhancing ion transport dynamics. Despite these advantages, fabricating large-area, highly crystalline two-dimensional conjugated carbon-based frameworks and reproducing the superior transport performance of individual channels in large-scale practical applications remains a challenge. This is mainly because achieving an ordered and uniform arrangement or stacking of these materials during thin film fabrication while maintaining their unique structure and properties is difficult.

[0003] Currently, researchers have employed 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, easily leading to unclear framework structures. Especially for solution- and interface-based synthesis methods, the random motion of molecules and the free rotation of chemical bonds cannot trigger in-plane coupling or polymerization reactions, resulting in out-of-plane random growth of the framework and ultimately forming a three-dimensional (3D) disordered structure rather than a two-dimensional ordered crystalline film. This disordered structure and defects negatively impact the physical, chemical, and electronic properties of the material, significantly reducing charge and ion transport efficiency. Furthermore, from a molecular design perspective, the precise introduction of conjugated functional groups into two-dimensional conjugated carbon frameworks (CCFs) holds promise for endowing materials with unexpected properties and improving their performance in energy storage, catalysis, and separation. However, due to the lack of effective synthetic pathways, the precise functionalization of large-area, high-quality two-dimensional conjugated carbon frameworks remains extremely rare. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a two-dimensional alkyne-rich carbon framework fast-charging anode material, its preparation method, and its applications. This invention proposes a "molecular locking-weaving" strategy, which can suppress random molecular movement and free rotation of chemical bonds at immiscible liquid / liquid interfaces. This allows for the preparation of a large-area, highly crystalline, intrinsically mesoporous two-dimensional crystalline alkyne-rich carbon framework fast-charging anode material modified with carboxyl lithium, constructing ordered lithium-ion transport channels and significantly improving the lithium-ion diffusion rate.

[0005] The present invention provides the following technical solution: a two-dimensional alkyne-rich carbon framework fast-charging anode material, which is formed by dissolving two monomers in two immiscible solvents and performing Sonogashira coupling polymerization at the interface; or by adding the two monomers to an organic solvent and reacting them by heating in an oil bath to obtain the corresponding product; wherein the two monomers are bromine-containing organolithium and 1,4-diethynylbenzene.

[0006] Furthermore, the present invention provides a method for preparing a two-dimensional ytylene-rich carbon framework fast-charging anode material, comprising the following steps:

[0007] (1) Dissolve the bromine-containing monomer in ethanol, add excess LiOH·H2O, mix and stir, wash and dry to obtain bromine-containing organolithium powder;

[0008] (2) The bromine-containing organolithium powder obtained in step (1) is mixed with a catalyst, wherein the catalyst is Pd(PPh3)4 and CuI, and the amounts of Pd(PPh3)4 and CuI are 5-10% and 10-15% of the mass of the bromine-containing organolithium, respectively;

[0009] (3) React 1,4-diethynylbenzene with the mixture from step (2), wherein the molar ratio of 1,4-diethynylbenzene to bromine-containing organolithium is (2.4-10):1; the reaction is carried out by one of the following two schemes:

[0010] Option A: Dissolve bromine-containing organolithium powder and catalyst in water to form an aqueous phase, dissolve 1,4-diethynylbenzene in an organic solvent to form an organic phase, add the aqueous phase to the top of the organic phase, and allow it to stand for 2-5 days to react at the interface; or

[0011] Option B: Dissolve the bromine-containing organolithium powder and catalyst in a mixed organic solvent, then dissolve 1,4-diethynylbenzene in the same mixed organic solvent, heat in an oil bath and let stand for 2-5 days at a temperature of 90-100℃;

[0012] (4) The material obtained from the reaction is washed and purified to obtain the final product.

[0013] Preferably, in step (1), the bromine-containing monomer is selected from any one of tetrabromoterephthalic acid, tetrabromobenzene, tetrabromophenol, and tribromophenol.

[0014] Preferably, in step (3), the organic solvent is selected from one or more of dichloromethane, tetrahydrofuran, N,N-dimethylformamide, and toluene.

[0015] 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, and acetone.

[0016] Furthermore, the present invention also provides the application of the two-dimensional alkyne-rich carbon framework fast-charging anode material in the preparation of alkali metal ion batteries.

[0017] Furthermore, the present invention also provides an alkali metal ion battery, wherein the alkali metal ion battery comprises the two-dimensional alkyne-rich carbon framework fast-charging negative electrode material, electrolyte, lithium metal and positive electrode material.

[0018] Preferably, the lithium metal is provided by any one of the following lithium salts: lithium hexafluorophosphate, lithium perchlorate, lithium bis(fluorosulfonyl)imide, and lithium bis(trifluoromethylsulfonyl)imide.

[0019] Preferably, the electrolyte is selected from one or more of ethylene carbonate, dimethyl carbonate, fluoroethylene carbonate, propylene carbonate, and diethyl carbonate.

[0020] Preferably, the cathode material is selected from any one of ternary lithium-ion battery cathode materials, lithium cobalt oxide, lithium iron phosphate, and lithium-rich manganese-based materials.

[0021] The advantages of this invention over the prior art are:

[0022] (1) In this invention, a two-dimensional alkyne-rich carbon framework fast-charging anode material is prepared by interfacial synthesis. Two monomers are dissolved in two immiscible solvents and coupled polymerized at the interface. Alternatively, the two monomers can be added to an organic solvent and reacted by heating in an oil bath to obtain the corresponding product. The prepared two-dimensional alkyne-rich carbon framework fast-charging anode material has the characteristics of high crystallinity and large-area preparation. The preparation method is simple and efficient.

[0023] (2) The prepared two-dimensional alkyne-rich carbon framework fast-charging anode material can simultaneously regulate the ion transport channels inside the active material, the desolvation process at the electrode interface, and the composition of the SEI interface film, thus exhibiting excellent fast-charging performance. The material has the following characteristics: (a) High crystallinity ensures the orderliness of the internal structure of the material; (b) Large interlayer spacing and AB stacking structure promote the ion transport dynamics inside the material; (c) The carboxyl lithium groups on the material framework can promote electron delocalization and improve conductivity. Their abundant electrons can improve the surface potential of the material, enhance the adsorption of lithium ions, and promote the desolvation of lithium ions; (d) The strong polarity of the carboxyl lithium groups can transfer more electrons from the substrate to the electrolyte, thereby promoting PF6 - The decomposition of LiF generates an SEI film with LiF as the main component.

[0024] (3) The prepared carboxyl lithium-modified two-dimensional alkyne-rich carbon framework fast-charging anode material has excellent fast-charging performance in the field of lithium-ion batteries. Attached Figure Description

[0025] Figure 1 A schematic diagram illustrating the principle of the preparation method of the two-dimensional ytylene-rich carbon framework fast-charging anode material provided by the present invention;

[0026] Figure 2 Transmission electron microscope image of the two-dimensional ytylene-rich carbon framework fast-charging anode material prepared in this invention;

[0027] Figure 3 An atomic force microscope image of the two-dimensional ytylene-rich carbon framework fast-charging anode material prepared in this invention;

[0028] Figure 4 The X-ray photoelectron spectrum of C1s of the two-dimensional ytylene-rich carbon framework fast-charging anode material prepared in this invention.

[0029] Figure 5 The Raman spectrum of the two-dimensional ytylene-rich carbon framework fast-charging anode material prepared in this invention;

[0030] Figure 6 Nitrogen adsorption-desorption pore size distribution and pore size distribution diagram of the two-dimensional alkyne-rich carbon framework fast-charging anode material prepared in this invention.

[0031] Figure 7 The refined X-ray diffraction pattern of the two-dimensional ytylene-rich carbon framework fast-charging anode material prepared in this invention;

[0032] Figure 8 High-resolution transmission electron microscope image of the two-dimensional ytylene-rich carbon framework fast-charging anode material prepared in this invention.

[0033] Figure 9The rate performance of the two-dimensional ytylene-rich carbon framework fast-charging anode material prepared in this invention in lithium-ion batteries.

[0034] Figure 10 The two-dimensional acetylene-rich carbon framework fast-charging anode material prepared according to this invention was used in a lithium-ion battery at 5 A g. -1 Cyclic performance under certain conditions;

[0035] Figure 11 The two-dimensional ytylene-rich carbon framework fast-charging anode material prepared for this invention uses LiNi 0.8 Co 0.1 Mn 0.1 The fast charging performance of O2 (NCM811) ternary material as positive electrode in lithium-ion full battery under 6C conditions;

[0036] Figure 12 The two-dimensional ytylene-rich carbon framework fast-charging anode material prepared in this invention demonstrates the lithium-ion battery cycle performance under a monomer molar ratio of 4:1.

[0037] Figure 13 Transmission electron microscope image of the two-dimensional alkyne-rich carbon framework fast-charging anode material prepared for this invention, using tetrabromophenol as a bromine-containing monomer.

[0038] 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.

[0039] 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;

[0040] 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.

[0041] 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

[0042] 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.

[0043] Example 1: The two-dimensional ytylene-rich carbon framework fast-charging anode material of this example was prepared using the following method:

[0044] 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.

[0045] 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.

[0046] 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. LiNi00.8 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] Example 6: In this example, the negative electrode material prepared in Example 1 is used as the negative electrode, and NCM811 ternary material is used 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.

[0053] 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 pouch 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.

[0054] 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.

[0055] 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 method for preparing a two-dimensional hyperacetylenic carbon framework fast-charging negative electrode material, characterized in that, Includes the following steps: (1) Dissolve the bromine-containing monomer in ethanol, add excess LiOH·H2O, mix and stir, wash and dry to obtain bromine-containing organolithium powder; wherein, the bromine-containing monomer is selected from any one of tetrabromoterephthalic acid, tetrabromobenzene, tetrabromophenol, and tribromophenol; (2) The bromine-containing organolithium powder obtained in step (1) is mixed with a catalyst, wherein the catalyst is Pd(PPh3)4 and CuI, and the amounts of Pd(PPh3)4 and CuI are 5-10% and 10-15% of the mass of the bromine-containing organolithium, respectively; (3) React 1,4-diethynylbenzene with the mixture from step (2), wherein the molar ratio of 1,4-diethynylbenzene to bromine-containing organolithium is (2.4-10):1; the reaction is carried out by one of the following two schemes: Option A: Dissolve bromine-containing organolithium powder and catalyst in water to form an aqueous phase, dissolve 1,4-diethynylbenzene in an organic solvent to form an organic phase, add the aqueous phase to the top of the organic phase, and allow it to stand for 2-5 days to react at the interface; or Option B: Dissolve the bromine-containing organolithium powder and catalyst in a mixed organic solvent, then dissolve 1,4-diethynylbenzene in the same mixed organic solvent, heat in an oil bath and let stand for 2-5 days at a temperature of 90-100℃; (4) The material obtained from the reaction is washed and purified to obtain the final product.

2. The method of claim 1, wherein: In step (3), the organic solvent is selected from one or more of dichloromethane, tetrahydrofuran, N,N-dimethylformamide, and toluene.

3. The method of claim 1, 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.

4. A two-dimensional ytylene-rich carbon framework fast-charging anode material prepared by the method described in any one of claims 1-3.

5. The application of the two-dimensional acetylene-rich carbon framework fast-charging anode material according to claim 4 in the preparation of lithium-ion batteries.

6. An alkali metal battery characterized by: The battery comprises the two-dimensional acetylene-rich carbon framework fast-charging negative electrode material as described in claim 4, an electrolyte, lithium metal, and a positive electrode material.

7. The alkali metal battery according to claim 6, characterized in that: The lithium metal is provided by any of the following lithium salts: lithium hexafluorophosphate, lithium perchlorate, lithium bisfluorosulfonylimide, and lithium bistrifluoromethylsulfonylimide.

8. The alkali metal battery according to claim 6, characterized in that: The electrolyte is selected from one or more of ethylene carbonate, dimethyl carbonate, fluoroethylene carbonate, propylene carbonate, and diethyl carbonate.

9. The alkali metal battery according to claim 6, characterized in that: The cathode material is selected from any one of the following: ternary lithium-ion battery cathode materials, lithium cobalt oxide, lithium iron phosphate, and lithium-rich manganese-based materials.

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