In-situ growth of a foamed iron wrinkle-shaped ferrous sulfide positive electrode material and a preparation method and application thereof

Abstract

This invention discloses an in-situ grown wrinkled iron sulfide cathode material from foamed iron, its preparation method, and its applications, relating to the fields of electrochemistry and novel battery energy storage technologies. This invention utilizes a one-step hydrothermal method to grow wrinkled iron sulfide nanosheets in situ on the surface of foamed iron. The preparation process is simple, and the material can be directly used as a battery cathode without the need for additional binders and conductive agents. This material has a large specific surface area, abundant active sites, low interfacial impedance, and excellent catalytic performance. When applied to lithium-carbon dioxide batteries, it can significantly optimize the battery's electrochemical performance and improve cycle and rate characteristics. The process of this invention is easy to scale up for production and also provides new ideas for carbon capture and utilization technologies, showing broad application prospects in clean energy storage and other fields.

Description

Technical Field

[0001] This invention relates to the fields of electrochemistry and novel battery energy storage technology, and in particular to a foamed iron-grown wrinkled iron sulfide cathode material, its preparation method, and its application. Background Technology

[0002] The overexploitation and consumption of fossil fuels has not only triggered a global energy storage crisis, but also led to the emission of large amounts of greenhouse gases such as carbon dioxide, exacerbating climate warming and seriously restricting the sustainable development of human society. Developing efficient and clean new energy storage systems has become a key research focus in the energy field.

[0003] Lithium-carbon dioxide batteries are an advanced electrochemical technology that captures carbon dioxide and converts it into electrical energy. They boast a specific energy density of up to 1876 Wh / kg, far exceeding that of traditional lithium-ion batteries, and also exhibit a high discharge voltage (E0). Φ =2.80Vvs Li / Li + The battery reaction is 4Li + +3CO2 + 4e - ↔2Li2CO3+C is one of the important research directions for novel energy storage and CO2 conversion systems. It has broad application prospects in fields such as global warming control and Mars exploration, and has become one of the core research directions for novel energy storage and CO2 conversion systems. In recent years, it has received widespread attention and in-depth research from the scientific community.

[0004] However, the practical industrial application of lithium-carbon dioxide batteries still faces many key technological bottlenecks, among which the performance defects of cathode materials are the core factor restricting their development. Existing lithium-carbon dioxide battery cathodes generally suffer from slow reaction kinetics and large overpotential differences during charging and discharging. Most reported cathode materials have actual discharge voltages lower than the theoretical value of 2.81 V, while charging voltages exceed 4 V. Since the actual performance of the battery is positively correlated with the discharge potential and negatively correlated with the charging potential, excessively high overpotentials directly lead to a significant reduction in battery energy efficiency. Furthermore, traditional cathode material preparation often employs a process of coating powdered catalysts with binders and conductive agents. This process is not only cumbersome and costly, but also prone to catalyst particle agglomeration, leading to increased contact resistance at the electrode interface, reduced electron transport and CO2 diffusion efficiency, and further exacerbating polarization during battery charging and discharging. Moreover, coated electrodes are prone to active material detachment and structural collapse during cyclic charging and discharging, severely affecting the battery's cycle stability and lifespan.

[0005] As the core site of the reversible CO2 reduction / oxidation reaction in lithium-carbon dioxide batteries, the cathode material's catalytic activity, electron transport efficiency, and structural stability directly determine the battery's overall performance. Therefore, developing a cathode material with high catalytic activity, low interfacial impedance, and structural stability, while simplifying its preparation process and reducing production costs, is crucial to overcoming the technological bottlenecks of lithium-carbon dioxide batteries and promoting their practical application. Against this backdrop, developing binder-free and agent-free in-situ grown cathode materials, allowing the active catalytic material to be directly loaded onto the conductive substrate surface, achieves a strong bond between the active material and the substrate. This reduces interfacial contact resistance, improves electron and mass transport efficiency, and avoids catalyst agglomeration and active material detachment. This has significant practical implications and research value for improving the overall performance of lithium-carbon dioxide batteries and accelerating their industrialization. Summary of the Invention

[0006] The purpose of this invention is to provide an in-situ grown wrinkled iron sulfide cathode material with foamed iron, its preparation method and application, so as to solve the problems existing in the prior art.

[0007] To achieve the above objectives, the present invention provides the following solution: One technical solution of the present invention provides an in-situ grown wrinkled iron sulfide cathode material, comprising an iron foam substrate and wrinkled iron sulfide nanosheets grown in situ on the surface of the iron foam substrate, and without containing any added binders or conductive agents; the chemical formula of the wrinkled iron sulfide nanosheets is Fe. 1-x S, where 0 <x<1。

[0008] This invention also provides a method for preparing the above-mentioned foamed iron in situ grown wrinkled iron sulfide cathode material, comprising the following steps: Foamed iron is immersed in a mixed solvent containing a sulfur source and a reducing agent, and a cationic surfactant is added to carry out a hydrothermal reaction to obtain the foamed iron in situ grown wrinkled iron sulfide cathode material.

[0009] Cationic surfactants can be directionally adsorbed onto the sulfur source / iron interface through electrostatic adsorption, precisely inducing the in-situ growth of iron sulfide on the substrate surface to form a wrinkled nanosheet structure. Simultaneously, cationic surfactants can also disperse the sulfur source, ensuring a complete reaction and regulating the morphology of iron sulfide. The dosage must be precisely controlled; too low a dosage will result in an indistinct wrinkled morphology of the iron sulfide, while too high a dosage can easily lead to impurities and affect product performance.

[0010] The molar ratio of the cationic surfactant to the sulfur source is 0.05:1 to 0.4:1.

[0011] Furthermore, the sulfur source is sulfur powder, and the reducing agent is hydrazine hydrate.

[0012] Furthermore, the hydrothermal reaction is carried out at a temperature of 150-170 °C for a duration of 10-14 h.

[0013] Furthermore, the cationic surfactant is hexadecyltrimethylammonium bromide (CTAB).

[0014] The second technical solution of this invention provides the application of the above-mentioned foamed iron in situ grown wrinkled iron sulfide cathode material in lithium-carbon dioxide batteries.

[0015] The third technical solution of the present invention provides a lithium-carbon dioxide battery, wherein the positive electrode material is the above-mentioned foamed iron in situ grown wrinkled iron sulfide positive electrode material.

[0016] Furthermore, the negative electrode of the lithium-carbon dioxide battery is a metallic lithium sheet, the separator is a glass fiber separator, and the electrolyte is an organic ether solution containing lithium salt.

[0017] The present invention discloses the following technical effects: This invention provides an in-situ grown wrinkled iron sulfide cathode material on foamed iron. It uses a one-step hydrothermal method to achieve in-situ growth of wrinkled iron sulfide on a foamed iron substrate. The entire process does not require complex production equipment, has a simple operation process, good process repeatability, and has the practical conditions for industrial mass production, effectively reducing the preparation cost of lithium-carbon dioxide battery cathode materials.

[0018] The wrinkled iron sulfide prepared by this invention has a nanosheet structure with a large specific surface area and abundant catalytic active sites, which can significantly increase the contact area for CO2 reduction / oxidation reactions. Moreover, the material is tightly bonded to the foamed iron substrate through in-situ growth, without the need for additional binders and conductive agents, effectively reducing the contact resistance at the electrode interface, accelerating electron transport and the diffusion rate of CO2 inside the electrode, and ensuring the excellent conductivity and mass transfer performance of the material.

[0019] Applying the material of this invention to the cathode of a lithium-carbon dioxide battery can reduce the overpotential of the battery charge and discharge to below 0.3 V, significantly improving the battery reaction kinetic efficiency. The battery discharge platform breaks through the theoretical value and is raised to above 2.9 V, exhibiting excellent cycle stability and rate characteristics over a wide current density range. It can achieve stable cycling for over 700 hours while maintaining 100% coulombic efficiency, greatly improving the problems of slow reaction kinetics and short cycle life of existing lithium-carbon dioxide batteries.

[0020] This invention not only provides a high-performance, low-cost cathode material solution for the development of lithium-carbon dioxide batteries, promoting the practical application of lithium-carbon dioxide batteries; but also, based on the battery's CO2 capture and electrochemical conversion characteristics, it provides a new approach to the development of carbon capture and utilization technology, with broad application prospects in multiple fields such as clean energy storage, global warming control, and deep space exploration, possessing both outstanding technical and social value. Attached Figure Description

[0021] 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 introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a scanning electron microscope (SEM) image of the in-situ grown wrinkled iron sulfide cathode material obtained in Example 1.

[0023] Figure 2 The image shows the X-ray diffraction (XRD) pattern of the in-situ grown wrinkled iron sulfide cathode material obtained in Example 1.

[0024] Figure 3 The lithium-carbon dioxide battery assembled using the cathode material obtained in Example 1 operates at 20 μA•cm. -2 Full charge-discharge curves at current density.

[0025] Figure 4 The lithium-carbon dioxide battery assembled using the cathode material obtained in Example 1 operates at 20~100 μA•cm. -2 At current density of 100 μAh•cm -2 Rate performance curve of cutoff capacity.

[0026] Figure 5 The lithium-carbon dioxide battery assembled using the cathode material obtained in Example 1 operates at 20 μA•cm. -2 At current density of 100 μAh•cm -2 Cyclic performance curves for cutoff capacity.

[0027] Figure 6 This is a scanning electron microscope (SEM) image of the in-situ grown wrinkled iron sulfide cathode material obtained in Example 2.

[0028] Figure 7The graph shows the cycle performance of the lithium-carbon dioxide battery assembled with the cathode material obtained in Example 2 at a current density of 20 μA•cm-2 and a cutoff capacity of 100 μAh•cm-2.

[0029] Figure 8 This is a scanning electron microscope (SEM) image of the in-situ grown wrinkled iron sulfide cathode material obtained in Example 3.

[0030] Figure 9 The graph shows the cycle performance of the lithium-carbon dioxide battery assembled with the cathode material obtained in Example 3 at a current density of 20 μA•cm-2 and a cutoff capacity of 100 μAh•cm-2.

[0031] Figure 10 This is a scanning electron microscope (SEM) image of the in-situ grown wrinkled iron sulfide cathode material obtained in Example 4. Figure 11 The lithium-carbon dioxide battery assembled using the cathode material obtained in Example 4 operates at 20 μA•cm. -2 At current density of 100 μAh•cm -2 Cyclic performance curves for cutoff capacity. Detailed Implementation

[0032] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0033] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0034] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0035] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be readily apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0036] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0037] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.

[0038] In a first aspect, the present invention provides a foamed iron in situ grown wrinkled iron sulfide cathode material, comprising a foamed iron substrate and wrinkled iron sulfide nanosheets grown in situ on the surface of the foamed iron substrate, and without containing any external binder or conductive agent. The chemical formula of the wrinkled iron sulfide nanosheets is Fe. 1-x S, where 0 <x<1。

[0039] A second aspect of this invention provides a method for preparing an in-situ grown, wrinkled iron sulfide cathode material, comprising the following steps: Foamed iron is immersed in a mixed solvent containing a sulfur source and a reducing agent, and a surfactant is added to carry out a hydrothermal reaction to obtain the foamed iron in situ grown wrinkled iron sulfide cathode material.

[0040] Furthermore, the preferred preparation steps for the in-situ growth of the wrinkled iron sulfide cathode material in the present invention are as follows: (1) Pretreatment of foamed iron: The foamed iron is cut into the preset size, immersed in the prepared dilute hydrochloric acid solution and ultrasonically cleaned to remove the surface oxide layer. Then it is repeatedly washed with ultrapure water and dried in a vacuum oven to obtain the treated foamed iron. (2) Preparation of reaction system: Add sulfur powder to a mixed solution of deionized water and hydrazine hydrate, stir until uniformly mixed, and obtain a homogeneous reaction solution; (3) In-situ growth reaction: The pretreated foamed iron is placed in a high-pressure reactor, the reaction solution prepared in step (2) is poured in, and then the surfactant (CTAB) is added. After sealing, it is placed in an environment of 150~170 ℃ for hydrothermal reaction for 10~14 h. (4) Post-processing: After the reaction is completed, the foamed iron is taken out and washed repeatedly with ultrapure water and ethanol in turn. Then it is dried in a vacuum oven to obtain the cathode material loaded with wrinkled iron sulfide.

[0041] In a preferred embodiment of the present invention, the thickness of the foamed iron is 0.3 mm and the porosity is 110 ppi.

[0042] In a preferred embodiment of the present invention, the foam iron pickling time is 15-30 min.

[0043] In a preferred embodiment of the present invention, the vacuum drying time is 6 to 12 hours.

[0044] In a preferred embodiment of the present invention, the temperature is increased from room temperature to the hydrothermal reaction temperature at a heating rate of 1~5°C / min.

[0045] In a preferred embodiment of the present invention, the ultrasonic cleaning power is 100~150 W; continuous stirring can also be performed during the cleaning process to improve the effect of removing the oxide layer.

[0046] A third aspect of the present invention also provides a lithium-carbon dioxide battery, wherein the positive electrode material is the above-mentioned foamed iron in situ grown wrinkled iron sulfide positive electrode material.

[0047] Furthermore, the negative electrode of the lithium-carbon dioxide battery is a metallic lithium sheet, the separator is a glass fiber separator, and the electrolyte is an organic ether solution containing lithium salt.

[0048] In the following embodiments of the present invention, the materials and reagents used can be purchased commercially unless otherwise specified; the "room temperature" is 25°C.

[0049] In the following embodiments of the present invention, the experimental testing instruments and battery assembly process are as follows: 1. Materials characterization and electrochemical testing instruments Microscopic morphology characterization: The morphology of the material was characterized using a scanning electron microscope (SEM) with a Hitachi S4800 instrument (Hitachi High-Tech (Shanghai) International Trading Co., Ltd.).

[0050] Crystal structure characterization: The phase composition of the material was analyzed using an X-ray diffractometer (XRD) model Bruker D8 (USA).

[0051] Electrochemical performance testing: The battery's full charge-discharge performance and long-cycle stability were tested using the Land Battery Testing System (Wuhan, China). The set current density for both rate performance and cycle life tests was 20 μA cm⁻¹. -2 .

[0052] 2. Preparation of positive electrode sheet for lithium-carbon dioxide batteries The foamed iron substrate loaded with active material prepared by the above method was cut into square electrode sheets with a side length of 1 cm and used directly as the positive electrode of lithium-carbon dioxide battery; electrochemical tests were carried out in a CO2 atmosphere.

[0053] The design of the positive electrode material in this invention does not require the addition of additional binders and conductive agents.

[0054] 3. Assembly of button-type lithium-carbon dioxide batteries All battery assembly was conducted in a strictly controlled inert atmosphere glove box, with an argon atmosphere and water and oxygen content both below 0.01 ppm. The specific assembly steps are as follows: a. Negative electrode preparation: Inside the negative electrode casing of the CR2032 button cell, place the spring, gasket, lithium metal sheet (negative electrode), and glass fiber separator (model: GF / D) in sequence.

[0055] b. Electrolyte injection: Add 50 μL of electrolyte to the diaphragm surface to ensure full wetting. The electrolyte used is a solution of 1 M lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) dissolved in tetraethylene glycol dimethyl ether (TEGDME).

[0056] c. Positive electrode installation and packaging: Place the cut positive electrode sheet on top of the separator and cover it with the positive electrode shell.

[0057] d. Sealing: The battery is pressed and sealed using an electric sealing machine to finally obtain a complete CR2032 coin cell lithium-carbon dioxide battery.

[0058] Example 1 This embodiment provides an in-situ grown wrinkled iron sulfide cathode material using foamed iron. The preparation steps are as follows: (1) Pretreatment of foamed iron: The foamed iron (thickness 0.3 mm, porosity 110 ppi) was cut into 1×2 cm, immersed in dilute hydrochloric acid solution and ultrasonically cleaned (150W) to remove the surface oxide layer, then repeatedly cleaned with ultrapure water and dried in a vacuum oven to obtain the treated foamed iron. (2) Preparation of reaction solution: Weigh 3 mmol of sulfur powder, add 14.03 mL of deionized water, and then add 0.93 mL of 80% hydrazine hydrate solution. Stir thoroughly at 200 rpm at room temperature until a uniform yellow clear homogeneous reaction solution is formed. (3) Hydrothermal in-situ growth: The above homogeneous reaction solution was transferred to a 25 mL high-pressure reactor, 0.2 g of surfactant CTAB was weighed and added to the reactor, and one piece of pretreated foamed iron was placed in it. After sealing the high-pressure reactor, it was placed in a forced-air drying oven and heated from room temperature to 160°C at a heating rate of 5°C / min. The temperature was kept constant for 12 h. After the reaction was completed, it was naturally cooled to room temperature. (4) Post-processing: The reacted iron foam material was taken out and rinsed repeatedly with ultrapure water and ethanol to remove residual impurities on the surface. Then it was placed in a vacuum oven and dried for 6 h to obtain the in-situ grown wrinkled iron sulfide cathode material (defect-state wrinkled iron sulfide (Fe)). 1-x S).

[0059] The cathode material obtained in this embodiment was characterized. Figure 1 The image shows a scanning electron microscope (SEM) image of the in-situ grown wrinkled iron sulfide cathode material obtained in Example 1. Figure 2 The image shows the X-ray diffraction (XRD) pattern of the in-situ grown wrinkled iron sulfide cathode material obtained in Example 1. It can be seen that the SEM image shows the material as a regular wrinkled nanosheet structure, and the characteristic peaks of the XRD pattern are consistent with those of Fe. 1-x The PDF#29-0725 standard card of S is a perfect match.

[0060] The lithium-carbon dioxide battery obtained in this embodiment operates at 20 μA•cm. -2 At a current density of [value missing], the initial discharge capacity reached 4.81532 mAh, which translates to an area discharge capacity of 4815.32 μAh•cm². -2 The relevant test results are shown in Figure 3; within the range of 20~100 μA•cm -2 At different current densities, at 100 μAh•cm -2 Testing was conducted to determine the cutoff capacity. The battery exhibited excellent rate performance with good stability and low charge / discharge overpotential. The relevant test results are shown in Figure 4. At 20 μA•cm -2 Current density, 100 μAh•cm -2 Under the cutoff capacity condition, the battery can achieve 75 stable cycles, and the relevant test results are shown in Figure 5.

[0061] Example 2 This embodiment provides an in-situ grown wrinkled iron sulfide cathode material using foamed iron. The preparation steps are as follows: (1) Pretreatment of foamed iron: The foamed iron (thickness 0.3 mm, porosity 110 ppi) was cut into 1×2 cm, immersed in dilute hydrochloric acid solution and ultrasonically cleaned (150W) to remove the surface oxide layer, then repeatedly cleaned with ultrapure water and dried in a vacuum oven to obtain the treated foamed iron. (2) Preparation of reaction solution: Weigh 3 mmol of sulfur powder, add 14.03 mL of deionized water, and then add 0.93 mL of 80% hydrazine hydrate solution. Stir thoroughly at 200 rpm at room temperature until a uniform yellow clear homogeneous reaction solution is formed. (3) Hydrothermal in-situ growth: The above reaction solution was transferred to a 25 mL high-pressure reactor, 0.1 g of surfactant CTAB was weighed and added into the reactor and dispersed evenly, one piece of pretreated foam iron was placed in the reactor, the high-pressure reactor was sealed and placed in a forced-air drying oven, the temperature was raised to 160℃ at a heating rate of 5℃ / min, and the reaction was kept at a constant temperature for 12 h. After the reaction was completed, it was naturally cooled to room temperature. (4) Post-processing: Take out the foamed iron material after the reaction, rinse it repeatedly with ultrapure water and anhydrous ethanol to remove residual impurities on the surface, and then dry it in a vacuum oven for 6 hours to obtain the positive electrode material of in-situ grown wrinkled iron sulfide foamed iron.

[0062] The cathode material obtained in Example 2 was characterized. Figure 6 The scanning electron microscope image shows the in-situ grown wrinkled iron sulfide cathode material obtained in Example 2. This in-situ grown wrinkled iron sulfide cathode material was used as a lithium-carbon dioxide battery cathode at 20 μA•cm. -2 Current density, 100 μAh•cm -2 Under the cutoff capacity condition, the battery can achieve 25 stable cycles, and the relevant test results are shown in Figure 7.

[0063] Example 3 This embodiment provides an in-situ grown wrinkled iron sulfide cathode material using foamed iron. The preparation steps are as follows: (1) Pretreatment of foamed iron: The foamed iron (thickness 0.3 mm, porosity 110 ppi) was cut into 1×2 cm, immersed in dilute hydrochloric acid solution and ultrasonically cleaned (150W) to remove the surface oxide layer, then repeatedly cleaned with ultrapure water and dried in a vacuum oven to obtain the treated foamed iron. (2) Preparation of reaction solution: Weigh 3 mmol of sulfur powder, add 14.03 mL of deionized water, and then add 0.93 mL of 80% hydrazine hydrate solution. Stir continuously at 200 rpm at room temperature to obtain a uniform yellow clear homogeneous reaction solution. (3) Hydrothermal in-situ growth: Transfer the prepared reaction solution to a 25 mL high-pressure reactor, weigh 0.2 g of surfactant CTAB and add it into the reactor and disperse it fully, put in a piece of pretreated foam iron, seal the high-pressure reactor and place it in a forced-air drying oven, raise the temperature from room temperature to 160℃ at a heating rate of 5℃ / min, keep the temperature constant for 16 h, and allow the reactor to cool naturally to room temperature after the reaction is completed; (4) Post-processing: Take out the foamed iron material in the reactor and rinse it repeatedly with ultrapure water and anhydrous ethanol to completely remove the unreacted raw materials and by-products remaining on the surface. Then place it in a vacuum oven to dry for 6 hours to obtain the positive electrode material of foamed iron substrate loaded with wrinkled iron sulfide.

[0064] The cathode material obtained in Example 3 was characterized. Figure 8 The scanning electron microscope image shows the in-situ grown wrinkled iron sulfide cathode material obtained in Example 3. This in-situ grown wrinkled iron sulfide cathode material, used as a lithium-carbon dioxide battery cathode, was analyzed at 20 μA•cm. -2 Current density, 100 μAh•cm -2 Under the cutoff capacity condition, the battery can achieve 40 stable cycles, and the relevant test results are shown in Figure 9.

[0065] Example 4 This embodiment provides an in-situ grown wrinkled iron sulfide cathode material using foamed iron. The preparation steps are as follows: (1) Pretreatment of foamed iron: The foamed iron (thickness 0.3 mm, porosity 110 ppi) was cut into 1×2 cm, immersed in dilute hydrochloric acid solution and ultrasonically cleaned (150W) to remove the surface oxide layer, then repeatedly cleaned with ultrapure water and dried in a vacuum oven to obtain the treated foamed iron. (2) Preparation of reaction solution: Weigh 3 mmol of sulfur powder, add 14.03 mL of deionized water, and then add 0.93 mL of 80% hydrazine hydrate solution. Stir continuously at 200 rpm at room temperature to obtain a uniform yellow clear homogeneous reaction solution. (3) Hydrothermal in-situ growth: Transfer the prepared reaction solution to a 25 mL high-pressure reactor, weigh 0.4 g of surfactant CTAB and add it into the reactor and disperse it fully, put in a piece of pretreated foam iron, seal the high-pressure reactor and place it in a forced-air drying oven, raise the temperature from room temperature to 160℃ at a heating rate of 5℃ / min, keep the temperature constant for 16 h, and allow the reactor to cool naturally to room temperature after the reaction is completed; (4) Post-processing: Take out the foamed iron material in the reactor and rinse it repeatedly with ultrapure water and anhydrous ethanol to completely remove the unreacted raw materials and by-products remaining on the surface. Then place it in a vacuum oven to dry for 6 hours to obtain the positive electrode material of foamed iron substrate loaded with wrinkled iron sulfide.

[0066] The cathode material obtained in Example 3 was characterized. Figure 10The scanning electron microscope image shows the in-situ grown wrinkled iron sulfide cathode material obtained in Example 4. This in-situ grown wrinkled iron sulfide cathode material was used as a lithium-carbon dioxide battery cathode at 20 μA•cm. -2 Current density, 100 μAh•cm -2 Under the cutoff capacity condition, the battery can achieve 40 stable cycles, and the relevant test results are shown in Figure 11.

[0067] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A foamed iron in-situ grown wrinkled iron sulfide positive electrode material, characterized by, It includes a foamed iron substrate and wrinkled iron sulfide nanosheets grown in situ on the surface of the foamed iron substrate, and does not contain any added binders or conductive agents. The chemical formula of the corrugated iron sulfide nanosheet is Fe 1-x S, wherein 0 < x < 1.

2. The method of claim 1, wherein the method is characterized by: Includes the following steps: Foamed iron is immersed in a mixed solvent containing a sulfur source and a reducing agent, and a cationic surfactant is added to carry out a hydrothermal reaction to obtain the foamed iron in situ grown wrinkled iron sulfide cathode material.

3. The production method according to claim 2, characterized by, The sulfur source is sulfur powder, and the reducing agent is hydrazine hydrate.

4. The preparation method according to claim 2, characterized in that, The hydrothermal reaction is carried out at a temperature of 150-170 °C for 10-14 h.

5. The preparation method according to claim 2, characterized in that, The cationic surfactant is hexadecyltrimethylammonium bromide.

6. The application of the foamed iron in-situ grown wrinkled iron sulfide cathode material as described in claim 1 in lithium-carbon dioxide batteries.

7. A lithium-carbon dioxide battery, characterized in that, The positive electrode material is the foamed iron in situ grown wrinkled iron sulfide positive electrode material as described in claim 1.

8. The lithium-carbon dioxide battery according to claim 7, characterized in that, The negative electrode of the lithium-carbon dioxide battery is a metallic lithium sheet, the separator is a glass fiber separator, and the electrolyte is an organic ether solution containing lithium salt.

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