A SiO x C y Coated integrated integrated carbonaceous honeycomb architecture materials, preparation and applications

Abstract

A SiO x C y Coated integrated integrated carbonaceous honeycomb architecture material, preparation and application, belong to the field of electrochemical energy storage and functional nanocomposite materials. The material is prepared by low temperature pyrolysis strategy of co-sacrifice template, through metal salt-gel microsphere template precursor preparation, precursor pressing and double temperature zone one step sintering. It has the characteristics of simple preparation process, regular and controllable macrostructure, adjustable chemical composition; graphene carbonaceous matrix and SiO x C y Nanoparticle three-dimensional interconnection, in-situ growth of carbon nanotubes and other characteristics. As the negative material of lithium ion battery, it does not need traditional conductive agent, binder and current collector, and shows high reversible capacity and excellent cycle stability, suitable for electric vehicles, energy storage power station, household energy storage and standby power supply and other fields.

Description

Technical Field

[0001] This invention relates to a SiO x C y The coated integrated carbon honeycomb structure material and its preparation and application belong to the field of high-performance electrochemical energy storage materials and nanocomposite materials. Background Technology

[0002] With the rapid growth in demand for high-energy-density lithium-ion batteries, the traditional multi-component electrode system of "active material-conductive agent-binder-current collector" is gradually revealing its bottlenecks in synergistically improving energy density and power density. Taking the negative electrode as an example, the theoretical capacity of graphite electrodes is nearing its limit, while the weight proportion of its copper metal current collector is as high as 10-15 wt.%, further limiting the improvement of battery energy density. In addition, if the proportion of inactive components is reduced by increasing the electrode thickness (>150 μm), i.e., the areal capacity, it will be limited by the lag in ion / electron transport dynamics, making it difficult to achieve a significant increase in energy density.

[0003] To overcome this bottleneck, in recent years, on the one hand, silicon-oxygen-carbon compounds (SiO2) have been developed. x C y Due to its high specific capacity (1000-2500 mAh / g) and moderate volume expansion rate (<120%), SiO₂ has become an ideal alternative material to graphite anodes. x C y The carbon-based buffer phase and oxygen-bridged network in the electrode can form chemical bonds with the conductive medium (such as carbon black, carbon nanotubes (CNTs), graphene, etc.), effectively suppressing volume expansion and constructing efficient electron transport channels. On the other hand, current collector-free self-supporting electrodes have emerged. By constructing a three-dimensional conductive network and in-situ combining the active material with the conductive framework, the proportion of inactive components can be significantly reduced, thereby increasing the overall energy density of the electrode by 15-20%. Therefore, combining these two material technologies holds promise for constructing novel high-performance lithium-ion battery anodes with significantly improved performance.

[0004] Despite this, the construction of thick electrodes still faces dual challenges in terms of mechanical strength and electrochemical stability. Under high areal loading, electrodes are prone to structural collapse, and the increased solid-solid interface contact resistance leads to intensified polarization. Therefore, innovative electrode microstructure design and composite systems are urgently needed to break through the limitations of traditional layered architectures and provide a new technological paradigm for high-energy fast-charging batteries. Highly crystalline nanoporous graphene-like carbon materials are widely used in electrochemical energy storage, catalysis, and adsorption due to their high specific surface area, excellent conductivity, well-developed pore structure, and tunable properties. Among them, honeycomb nanoporous carbon materials prepared by the template method can significantly improve mass transfer efficiency, increase reactive sites, and effectively mitigate volume changes due to their regular three-dimensional pore structure. For example, the inventors' team previously developed a graphene-like carbon material with a highly regular three-dimensional ordered macroporous structure (3DOM) (patent number: CN201610565108.4), which exhibits excellent performance whether used as a lithium-ion battery anode or as an electrocatalyst for hydrogen evolution reaction. Based on this technology, the inventors' team further developed an integrated carbon honeycomb structure material (patent number: CN202410323102.0), which has great application potential in many fields such as electrochemical energy storage, catalysis, gas separation, adsorption, and electromagnetic shielding.

[0005] In view of this, the present invention proposes a SiO x C y An integrated, monolithic carbonaceous honeycomb structure material and its preparation method are presented. This composite system, through multi-scale structural design and catalytic functional integration, holds promise for achieving synergistic optimization of energy density, rate performance, and cycle life, thus driving the technological development of next-generation high-energy-density, high-safety rechargeable batteries. Currently, there are no literature reports on such materials and their related preparation technologies. Specifically, SiO₂... x C y When combined with 3DOM-type graphene carbon matrix, the structural and functional advantages of the carbon skeleton can be fully utilized: (1) Metal particles (such as Zn, Fe, Ni) or metal compounds introduced in situ into the carbon matrix can significantly enhance the interfacial electronic conduction. Their catalytic activity can also induce the in situ growth of CNTs on the pore walls, forming a multi-level interconnected conductive network, effectively reducing charge transfer impedance; (2) The 3DOM structure of the carbon skeleton provides a fast ion transport channel and synergistically accommodates SiO with mesopores / micropores. x C y (3) The carbon matrix can replace the traditional copper current collector to improve the electrode energy density and power density, while increasing the overall thickness of the electrode and reducing the use of inactive components; (4) The synergistic effect of metal compounds and carbon matrix can regulate the composition of the surface solid electrolyte membrane (SEI) and enhance the interface stability. Summary of the Invention

[0006] The purpose of this invention is to provide a SiO x C y An integrated, monolithic carbonaceous honeycomb structure material with coating and its preparation method are presented. This method involves a simple preparation process, yielding samples with a regular and controllable macroscopic structure (e.g., shape, thickness) and a rich and tunable chemical composition, including SiO₂. x C y It is integrated with a graphene carbon matrix in three dimensions. Simultaneously, the pore walls used to construct the honeycomb microstructure are embedded with metals and / or metal compounds, and dense carbon nanotubes (CNTs) are grown in situ on the pore walls. When used as an electrode material for lithium-ion batteries, the material exhibits high energy storage capacity, rate performance, and long-term cycle stability. As a negative electrode material for lithium-ion batteries, it eliminates the need for traditional conductive agents, binders, and current collectors, exhibiting high reversible capacity and excellent cycle stability, making it suitable for electric vehicles, energy storage power stations, home energy storage, and backup power supplies.

[0007] A SiO x C y The encapsulated integrated carbon honeycomb structure material is characterized by a macroscopically three-dimensional porous honeycomb structure material, with pore walls comprising a graphene carbon matrix, carbon nanotubes (CNTs), metallic substances, and SiO₂. x C y Composition, and SiO x C y A three-dimensional porous structure is formed by coating the pore wall surface and the overall honeycomb structure material, wherein the metallic material includes zero-valent metals and / or metal compounds, and the metal compounds are metal silicides.

[0008] The metal mentioned is one or more of zinc, nickel, aluminum, iron, etc.

[0009] The SiO x C y It is a silicon-oxygen-carbon composite material, mostly existing in an amorphous state, with a controllable chemical composition, combining the high capacity properties of silicon with the buffering effect of carbon / oxygen; the metal compound is a metal silicide (such as Ni). 31 Si 12 (etc.); the graphene carbonaceous material is pure graphene-like carbon, graphene-like carbon with low graphitization degree, graphene-like carbon rich in defects, etc.; the CNT system is generated in situ during the preparation process.

[0010] This composite material has the following structural characteristics: large geometric dimensions, regular shape, and SiO₂ content. x C y The SiO2 material is densely and uniformly loaded onto the surface and pore walls of a three-dimensional porous honeycomb structure, resulting in a three-dimensional ordered conductive network with high porosity and large specific surface area. x Cy It is a silicon-oxygen-carbon composite material, mostly existing in an amorphous state. Its chemical composition can be controlled, combining the high lithium storage capacity of silicon with the buffering effect of carbon / oxygen.

[0011] This invention provides a SiO x C y A method for preparing an integrated, one-piece carbonaceous honeycomb structure material, characterized by comprising the following steps:

[0012] (1) Prepare a solution by mixing complexing agent (such as citric acid) and metal salt (such as zinc nitrate, nickel nitrate, aluminum nitrate, iron nitrate and other nitrates) in a certain proportion as a precursor impregnation solution;

[0013] (2) The organic colloidal microsphere template (such as polymethyl methacrylate microsphere template) with irregular block or small particle shape is fully impregnated in the above precursor solution, filtered and dried to obtain the primary precursor;

[0014] (3) Weigh the primary precursor from step (2) and place it in the mold cavity for tableting (in this embodiment of the invention, a commercial infrared tablet press is used, and the mold diameter is 15.4 mm). After holding it under a certain pressure for a period of time, a block precursor with a macroscopic mold cavity shape is obtained.

[0015] (4) Place the preform pressed into a block shape in step (3) in the high-temperature zone of a dual-temperature zone tube furnace, and weigh a certain amount of silane coupling agent and place it in the low-temperature zone of the dual-temperature zone tube furnace. Calcinate at a set temperature under a specific atmosphere for a period of time. The low-temperature zone provides carbon and silicon sources to the material in the high-temperature zone through a carrier gas. After calcination, cool to room temperature to obtain SiO2 with a mold shape. x C y The encapsulated integrated carbon honeycomb structure material results in a honeycomb structure with SiO₂ cells inlaid with metal or metal compounds. x C y The graphene-coated carbonaceous matrix has dense CNTs growing in situ on its pore walls.

[0016] Furthermore, the concentration of citric acid complexing agent in the precursor solution prepared in step (1) of the present invention is 0.5-2 mol / L, preferably 1 mol / L.

[0017] Furthermore, the concentration of the metal salt in the precursor solution prepared in step (1) of the present invention is 1-3 mol / L, preferably 2 mol / L.

[0018] Furthermore, the immersion conditions described in step (2) of the present invention are immersion at room temperature for 3-16 hours, preferably immersion at room temperature for 12 hours.

[0019] Furthermore, the pressure applied during tablet compression is 4-10 MPa, preferably 6 MPa; the pressure holding time is 10-60 s, preferably 30 s.

[0020] Furthermore, in step (4) of the present invention, the silane coupling agent is selected from KH-560 (3-glycidyloxypropyltrimethoxysilane), and its mass is 0.1-10 times that of the bulk precursor material, preferably 5 times.

[0021] Further, the calcination temperatures corresponding to the two different temperature zones in step (4) of the present invention are 350°C in the low-temperature zone and 450-1000°C in the high-temperature zone; the heating rate in the high-temperature zone is 1-30°C / min, preferably 10°C / min; the reaction atmosphere is nitrogen, argon or hydrogen-argon mixture; the gas flow rate is 1-500 sccm, preferably 5 sccm; the holding time is 0-2h, preferably 20min; and the distance between the low-temperature zone and the high-temperature zone is 10-80cm, preferably 20-30cm.

[0022] Furthermore, in step (4) of this invention, an inert carrier gas is introduced into the tubular furnace along its axial length. Along the gas flow direction, the low-temperature zone is located in front of the high-temperature zone, and both zones are heated separately. Both zones are heated from room temperature to their respective target temperatures in the same time and then held at that temperature. The silane coupling agent vaporized in the low-temperature zone is carried by the carrier gas to the high-temperature zone and deposited on the surface of the carbonaceous honeycomb structure, then naturally cools to room temperature.

[0023] Furthermore, if a cylindrical cavity mold is used in step (3) of the present invention, then the target material obtained in step (4) is SiO with a circular shape and uniform thickness. x C y The coating is an integrated carbon honeycomb structure material with a thickness of several hundred nanometers to millimeters, preferably 100-1000 micrometers; the mass of the precursor mentioned in step (3) is 60-200mg, preferably 120mg; the geometry and area of ​​the cavity are determined by the specific mold size and are in principle unlimited.

[0024] The preparation method provided by this invention has the following beneficial effects:

[0025] This invention provides a SiO x C yThe preparation method of the encapsulated integrated carbon honeycomb structure material, based on a low-temperature pyrolysis strategy using a co-sacrificial template, involves three main steps: preparation of a metal salt-colloidal microsphere template precursor, precursor pressing, and dual-temperature zone calcination in a tube furnace. This method yields a target material with a regular shape and uniform thickness. Specifically: (a) materials with different chemical compositions can be prepared by changing the types of metal salt, complexing agent, and microsphere template; (b) the geometry, area, and thickness of the material can be easily adjusted by changing the mold shape, precursor dosage, applied pressure, and holding time; and (c) the SiO₂ content can be adjusted by changing the amount of silane coupling agent and the calcination procedure. x C y The coating amount and CNT growth amount. The material prepared by this method is used as an electrode material for lithium-ion batteries, exhibiting high reversible capacity, rate performance and long cycle stability.

[0026] The chemical composition, crystal structure, morphology, and other physical properties of the obtained materials were determined using instruments such as a SmartLab X-ray diffractometer (XRD), an S4800 field emission scanning electron microscope (SEM), and a JEMF200 field emission transmission electron microscope (TEM). The lithium-ion battery performance of the prepared materials was tested using the Xinwei Battery Testing System.

[0027] For lithium-ion battery applications, 2032-type button cells were assembled in an argon-protected glove box (H2O < 0.5 ppm, O2 < 0.5 ppm), and the lithium-ion battery performance of the prepared materials was tested. The prepared composite material does not require a traditional copper current collector and can be directly used as an integrated electrode. Lithium foil was used as the counter electrode, Whatman glass fiber was used as the separator, and LiPF6 solution was used as the electrolyte (concentration of 1 mol / L, solvent is a mixture of dimethyl carbonate (DMC), diethyl carbonate (DEC), and ethylene carbonate (EC), with a volume ratio of 1:1:1). Button cells were assembled and their electrochemical performance was tested. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0029] Figure 1 The SiO prepared in Example 1 x C y Optical photograph of the encapsulated, integrated, monolithic carbon honeycomb structure material.

[0030] Figure 2X-ray diffraction patterns of (a) samples 1-3, (b) Fourier transform infrared spectrum of sample 1, and (c) Raman spectrum of sample 1 obtained in Example 1.

[0031] Figure 3 These are SEM images of the cross-sectional positions (high magnification and low magnification) of the material prepared in Example 1: Sample 1 (a, b), Sample 2 (c, d), and Sample 3 (e, f).

[0032] Figure 4 This is a TEM image of sample 1 obtained in Example 1.

[0033] Figure 5 This is a graph showing the rate and cycle performance of the lithium-ion battery assembled from sample 1 prepared in Example 2. Detailed Implementation

[0034] To further illustrate the present invention, the SiO provided by the present invention will be described below with reference to the accompanying drawings and embodiments. x C y The integrated, one-piece carbon honeycomb structure material used for coating is described in detail, but should not be construed as limiting the scope of protection of this invention. Any product identical or similar to this invention, derived from the teachings of this invention or by combining features of this invention with other prior art, should fall within the scope of protection of this invention.

[0035] The specific operating and testing methods used in this invention are all conventional methods in the field. Unless otherwise specified, conventional experimental operations or conditions described in the literature in this field can be followed. The reagents involved in this invention are all existing commercially available products.

[0036] All embodiments of this patent use a commercial infrared tablet press for precursor tableting. The shape and size of the mold and other physical parameters can be freely adjusted according to requirements. The present invention uses a cylindrical mold with a diameter of 15.4 mm to prepare samples for the following embodiments.

[0037] Example 1

[0038] This embodiment provides a SiO x C y The encapsulated, integrated, monolithic carbonaceous honeycomb structure material. (From...) Figure 1 and Figure 3 It can be seen that the obtained material is in the shape of a disc, with a geometric diameter of approximately 13.0 mm, and the thickness and load capacity show a gradient increasing trend; from Figure 2 It can be seen that the main component of this material is a silicon-oxygen-carbon composite material (SiO2). x C y ), elemental nickel, and nickel silicides (Ni 31 Si 12) and low-graphitization graphene-like carbon. Its preparation method includes the following steps:

[0039] (1) Prepare a solution of nickel nitrate and citric acid as a precursor impregnation solution; the concentration of citric acid in the precursor solution is 1 mol / L and the concentration of nickel nitrate is 2 mol / L;

[0040] (2) The irregular block or small particle-shaped PMMA microsphere template was immersed in the above precursor solution for 12 hours, filtered and dried to obtain the initial precursor.

[0041] (3) Weigh 120mg of the precursor from step (2), place it in a cylindrical mold with a diameter of 15.4mm for tableting, and hold it under a pressure of 6MPa for 30s to obtain a circular tablet precursor.

[0042] (4) Place the precursor pressed into a disc shape in step (3) in the high-temperature zone of a dual-temperature zone tube furnace (three samples are placed in a reaction device at the same time and arranged in a line along the gas flow direction, and heated at the same time, wherein the distances of sample 1, sample 2, and sample 3 from the low-temperature zone are 20cm, 25cm, and 30cm, respectively). Weigh 5 times the mass of the precursor silane coupling agent KH560 and place it in the low-temperature zone of the dual-temperature zone tube furnace. In a hydrogen-argon mixed atmosphere of 5 sccm, the high-temperature zone is heated to 1050℃ at a heating rate of 10℃ / min, and the low-temperature zone is heated to 350℃ at the same heating time. After holding at the same temperature for 20 min, cool to room temperature to obtain the product.

[0043] from Figure 2 It can be seen that the metal exists in the form of zero-valent metal and metal silicide.

[0044] Example 2

[0045] A 2032-type button cell was assembled in an argon-protected glove box (H₂O < 0.5 ppm, O₂ < 0.5 ppm). Sample 1 material prepared in Example 1 was used directly as the integrated electrode (without a traditional copper current collector). Lithium foil was used as the counter electrode, Whatman glass fiber as the separator, and LiPF₆ solution (1 mol / L concentration, a mixture of DMC, DEC, and EC in a 1:1:1 volume ratio) as the electrolyte. Electrochemical performance was then tested. The electrochemical performance tests were conducted at room temperature, with a voltage range of 2.0–0.01 V. Figure 5 The test results showed that when the current density was 0.67 mA / cm² 2 1.34 mA / cm 2 2.68 mA / cm 2 4.02mA / cm 2 and 5.36 mA / cm 2At that time, the average reversible specific capacity of the prepared material reached 4.81 mAh / cm³. 2 3.03mAh / cm 2 1.45mAh / cm 2 1.10mAh / cm 2 and 0.81mAh / cm 2 After completing the above rate performance tests, the current density returned to 0.67 mA / cm². 2 At that time, its specific capacity recovered to 3.77 mAh / cm³. 2 Further at 0.67 mA / cm 2 After undergoing long-cycle testing (80 cycles), its reversible specific capacity still reached 4.37 mAh / cm³. 2 The above results demonstrate that this material exhibits excellent rate performance and superior cycle stability.

Claims

1. A SiO x C y A method for preparing an integrated, one-piece carbonaceous honeycomb structure material with coating, characterized in that, The SiO x C y The encapsulated, integrated carbon honeycomb structure material is macroscopically a three-dimensional porous honeycomb structure material, with pore walls comprising a graphene carbon matrix, carbon nanotubes (CNTs), metallic substances, and SiO₂. x C y Meanwhile, SiO x C y A three-dimensional porous structure is formed by coating the surface of the pore walls and the overall honeycomb structure material, wherein the metallic material includes zero-valent metals and / or metal compounds, and the metal compounds are metal silicides; The metal mentioned is one or more of zinc, nickel, aluminum, and iron; The preparation method includes the following steps: (1) Prepare a solution by mixing the complexing agent and the metal salt in a certain proportion as a precursor impregnation solution; (2) The organic colloidal microsphere template with irregular block or small particle shape is fully impregnated in the above precursor impregnation solution, filtered and dried to obtain the primary precursor; (3) Weigh the primary precursor from step (2), place it in the mold cavity for tableting, and hold it under a certain pressure for a period of time to obtain a block precursor with the shape of the mold cavity. (4) Place the preform pressed into a block shape in step (3) in the high-temperature zone of a dual-temperature zone tube furnace, and weigh a certain amount of silane coupling agent and place it in the low-temperature zone of the dual-temperature zone tube furnace. Calcinate at a set temperature under a specific atmosphere for a period of time. The low-temperature zone provides carbon and silicon sources to the material in the high-temperature zone through a carrier gas. After calcination, cool to room temperature to obtain SiO with a mold shape. x C y The encapsulated integrated carbon honeycomb structure material results in a honeycomb structure with SiO₂ cells inlaid with metal or metal compounds. x C y The graphene-coated carbonaceous matrix has dense CNTs growing in situ on its pore walls. In step (4), the silane coupling agent is selected from KH-560 (3-glycidyloxypropyltrimethoxysilane), and its mass is 0.1-10 times that of the bulk precursor material; The two different temperature zones in step (4) correspond to calcination temperatures of 350 ℃ in the low-temperature zone and 450-1000 ℃ in the high-temperature zone, respectively; the heating rate in the high-temperature zone is 1-30 ℃ / min; the reaction atmosphere is nitrogen, argon, or a hydrogen-argon mixture; the gas flow rate is 1-500 sccm; the holding time is 0-2 h; and the distance between the low-temperature zone and the high-temperature zone is 10-80 cm. In step (4), an inert gas carrier gas is introduced into the tubular furnace along the axial length direction. Along the gas flow direction, the low-temperature zone is located in front of the high-temperature zone, and the low-temperature zone and the high-temperature zone are heated separately. The two temperature zones are heated from room temperature to their respective target temperatures in the same amount of time and then held at that temperature. The silane coupling agent vaporized in the low-temperature zone is carried by the carrier gas to the high-temperature zone and deposited on the surface of the carbon honeycomb structure, and then naturally cooled to room temperature.

2. The method according to claim 1, characterized in that, In step (1), the complexing agent is citric acid, and the concentration of citric acid complexing agent in the prepared precursor solution is 0.5–2 mol / L; The concentration of the metal salt in the precursor solution prepared in step (1) is 1–3 mol / L.

3. The method according to claim 2, characterized in that, The concentration of the citric acid complexing agent was 1 mol / L, and the concentration of the metal salt in the precursor solution was 2 mol / L.

4. The method according to claim 1, characterized in that, The immersion conditions described in step (2) are immersion at room temperature for 3–16 h.

5. The method according to claim 1, characterized in that, Step (3) When compressing tablets, apply a pressure of 4-10 MPa and maintain the pressure for 10-60 s.

6. The method according to claim 5, characterized in that, Step (3) Apply a pressure of 6 MPa during tablet compression; maintain the pressure for 30 s.

7. The method according to claim 1, characterized in that, In step (4), the mass of the silane coupling agent is 5 times that of the bulk precursor material; The heating rate in the high-temperature zone was 10 °C / min; the gas flow rate corresponding to the reaction atmosphere was 5 sccm; the holding time was 20 min; and the distance between the low-temperature zone and the high-temperature zone was 20-30 cm.

8. The method according to claim 1, characterized in that, If a cylindrical cavity mold is used in step (3), then the target material obtained in step (4) is SiO with a circular shape and uniform thickness. x C y The integrated carbon honeycomb structure material covering the cavity has a thickness of 100-1000 micrometers; the mass of the precursor weighed in step (3) is 60-200 mg; the geometry and area of ​​the cavity are determined by the specific mold size.

9. SiO prepared according to any one of claims 1-8 x C y The encapsulated, integrated carbon honeycomb structure material.

10. SiO prepared according to any one of claims 1-8 x C y The application of encapsulated, integrated carbon honeycomb structure material is directly used as an electrode in lithium-ion batteries.

11. The application according to claim 10, characterized in that, It can be used directly as a negative electrode material for lithium-ion batteries without conductive agents, binders, or current collectors.

Images