A high energy density iron-based sulfide thin film electrode and a method of preparing the same
By growing iron-based sulfide thin film electrodes in situ on a porous iron substrate, the problems of insufficient conductivity and structural stability of existing iron-based oxide and hydroxide materials are solved, achieving high energy density and simplifying the preparation process, making it suitable for large-scale energy storage.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- YANSHAN UNIV
- Filing Date
- 2022-10-11
- Publication Date
- 2026-05-29
AI Technical Summary
Existing iron-based oxide and hydroxide materials have shortcomings in terms of conductivity and structural stability, resulting in poor rate performance and cycle performance. Furthermore, their preparation processes are complex and cannot meet the needs of large-scale energy storage.
A one-step hydrothermal method is used to grow iron-based sulfide thin film electrodes in situ on the surface of a porous iron substrate, which simplifies the preparation process, eliminates the need for binders, and directly uses the porous iron substrate as the iron source and current collector. The hydrothermal reaction is carried out by mixing water, metal alkali, alkali metal sulfide and citrate.
It achieves high areal specific capacity and low discharge plateau, and the electrode has high energy density, making it suitable for large-scale energy storage. Moreover, the preparation process is simple and low-cost.
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Figure CN116130585B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of electrode materials technology, and in particular to a high-energy-density iron-based sulfide thin film material and its preparation method. Background Technology
[0002] The massive burning of fossil fuels to supply energy globally has raised concerns about environmental degradation, prompting the utilization of clean and renewable energy sources. However, the availability of natural resources is constrained by various uncontrollable natural factors, thus, research on low-cost, large-scale energy storage systems has entered a phase of rapid development. Commercial carbon-based supercapacitors possess high power densities (5–10 kW / kg). -1 It features a long cycle life (greater than 100 cycles) but a limited energy density (less than 10 Wh / kg). -1 This makes it unsuitable for large-scale energy storage. The widely used lithium-ion battery (LIB) has a suitable energy density (30–400 Wh / kg). -1 However, issues such as the availability and cost of lithium metal on Earth, as well as the safety of organic electrolytes, have prompted people to seek other low-cost systems that can be applied to large-scale energy storage.
[0003] Alkaline aqueous batteries are considered a promising energy storage system due to their low cost, high safety, and environmental friendliness. A variety of cathode materials are available, with significant progress made in nickel-based cathodes. However, anode materials with comparable performance are still lacking. Iron-based species, with their abundant valence states and redox reactivity, possess excellent electrochemical properties. Furthermore, iron is abundant in nature, inexpensive, safe, and non-toxic. Rechargeable nickel-iron batteries exhibit an ultra-flat discharge plateau and excellent stability and safety, making them promising for large-scale energy storage. Extensively studied iron-based oxides and hydroxides possess high theoretical specific capacity and a wide and stable operating potential window within the negative potential range, thus improving the operating voltage and energy density of aqueous batteries. However, poor conductivity and structural instability lead to decreased rate performance and unstable cycle performance. Additionally, the low hydrogen evolution overpotential of iron-based materials results in decreased coulombic efficiency. Iron-based sulfides, on the other hand, have a smaller band gap and therefore better conductivity, potentially improving rate and cycle performance. Moreover, the introduction of sulfur has been shown to inhibit the hydrogen evolution reaction. In addition, most existing technologies involve preparing active material powders and then coating them with paste to form electrodes, which inevitably introduces non-active substances such as binders, and the preparation process is cumbersome and complicated. Alternatively, iron-based active materials can be synthesized in situ on non-ferrous conductive substrates such as carbon cloth or graphene, in which case iron salts and other iron sources must be added to the reaction solution. There is still room for further simplification of the preparation method.
[0004] Therefore, inventing a high-performance, low-cost, simple-process iron-based sulfide anode material suitable for large-scale energy storage has certain development prospects and application value. Its performance indicators are mainly reflected in the following aspects: (1) high areal specific capacity and high energy density. Most related studies have achieved high mass specific capacity under low mass load, while areal specific capacity is also an important parameter in commercial applications; (2) low discharge platform. For anode materials, a lower discharge platform allows the battery to obtain a higher operating voltage, thereby achieving a higher energy density; (3) simple preparation process, economical raw materials, and environmentally friendly. Summary of the Invention
[0005] The purpose of this invention is to provide an iron-based sulfide thin film electrode for alkaline aqueous systems, which is simple to produce, easy to operate, has low production costs, and high energy storage activity, and is suitable for large-scale energy storage, as well as its preparation method.
[0006] The specific technical solution of the present invention is as follows:
[0007] A high-energy-density iron-based sulfide thin film electrode is fabricated by in-situ growth reaction on the surface of a porous iron substrate using a one-step hydrothermal method.
[0008] Preferably, the area loading of the iron-based sulfide thin film electrode is 141 mg / cm². -2 .
[0009] Preferably, the working mechanism of the iron-based sulfide thin film electrode in an alkaline system is as follows:
[0010] The present invention also provides the application of the iron-based sulfide thin film electrode in an aqueous battery, wherein the iron-based sulfide thin film electrode serves as the anode material of the aqueous battery.
[0011] The present invention also provides a method for preparing the iron-based sulfide thin film electrode, comprising the following steps:
[0012] (1) The surface of the porous iron matrix was ultrasonically pretreated with acetone, hydrochloric acid and anhydrous ethanol and then dried to remove impurities.
[0013] (2) A reaction solution is obtained by mixing water, metal alkali, alkali metal sulfide and citrate, with the mass ratio of metal alkali, alkali metal sulfide and citrate being (30-100):(30-270):(5-30);
[0014] (3) Immerse the porous iron matrix in the reaction solution and heat it to carry out a hydrothermal reaction, so that the porous iron matrix surface undergoes an in-situ growth reaction.
[0015] (4) Take out the porous iron substrate after hydrothermal treatment, wash it alternately with water and anhydrous ethanol and dry it to obtain the iron-based sulfide thin film electrode material.
[0016] Preferably, in step (2), the metal alkali is 30-100 g / L, and the metal alkali is selected from at least one of KOH and NaOH.
[0017] Preferably, in step (2), the alkali metal sulfide is 30-270 g / L, and the alkali metal sulfide is selected from sodium sulfide and potassium sulfide.
[0018] Preferably, in step (2), the citrate concentration is 5–30 g / L, and the citrate is selected from C6H5Na3O7, C6H5K3O7, and C6H 17 One or more of N3O7, C6H5O7(NH4)3, and C6H7NaO7.
[0019] Preferably, in step (3), the temperature of the hydrothermal reaction is 150-250°C and the time of the hydrothermal reaction is 12-24h.
[0020] Preferably, in step (3), the in-situ growth reaction uses a porous iron substrate as the iron source and current collector, and an in-situ electrochemical preparation is carried out on its surface to form an active material film, which serves as a self-supporting electrode without binder.
[0021] Compared with the prior art, the present invention has the following advantages:
[0022] 1. The production process is simple and easy to operate. Electrodes can be prepared in just one step using a hydrothermal method, eliminating cumbersome processes and using low-cost raw materials.
[0023] 2. This invention directly uses a porous iron matrix as the iron source and current collector, eliminating the need for the addition of iron salts during the synthesis process and eliminating the need for non-active substances such as binders during electrode preparation.
[0024] 3. This electrode has a high loading capacity of 141 mg cm⁻¹ -2 The discharge platform is as low as -0.8V (vs. Ag / AgCl), and the highest areal specific capacity is 31.74mAh cm⁻¹. -2 (Current density 50mA cm) -2 ).
[0025] 4. This electrode has high energy density and is suitable for large-scale energy storage. Attached Figure Description
[0026] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention, wherein:
[0027] Figure 1 The X-ray diffraction pattern of the electrode obtained in Embodiment 1 of the present invention;
[0028] Figure 2 This is a scanning electron microscope (SEM) image of the electrode obtained in Example 1 of the present invention.
[0029] Figure 3 The charging and discharging curves of the electrode obtained in Example 1 of the present invention under different current densities are shown.
[0030] Figure 4 This is a diagram showing the discharge area-to-capacity ratio of the electrode obtained in Embodiment 1 of the present invention under different current densities. Detailed Implementation
[0031] The following disclosure provides many different embodiments or examples for implementing different structures of the invention. To simplify the disclosure, specific examples of components and arrangements are described below. Of course, these are merely examples and are not intended to limit the invention. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed.
[0032] Example 1
[0033] First, the surface of the porous iron substrate is pretreated with acetone, hydrochloric acid, and anhydrous ethanol and then dried to obtain a bare porous iron substrate. Second, a reaction solution is prepared, consisting of 15 ml of deionized water, 40 g / L NaOH, 80 g / L sodium sulfide, and 5 g / L sodium citrate. Then, the reaction solution is placed in a reaction vessel, and the clean porous iron substrate is immersed in the reaction solution, and the reaction vessel is sealed. Next, the reaction vessel is placed in an oven and subjected to a hydrothermal reaction at 180°C for 24 hours to allow in-situ growth of the porous iron substrate surface. Finally, the hydrothermally treated porous iron substrate is removed, cleaned alternately with deionized water and ethanol, and then dried to obtain a high-energy-density iron-based sulfide thin-film electrode material.
[0034] The material is inexpensive, simple to synthesize, and its X-ray diffraction pattern is as follows. Figure 1 As shown, the iron-based sulfide thin film electrode material has been successfully synthesized; the scanning electron microscope morphology image is shown below. Figure 2 As shown, the microstructure of the prepared iron-based sulfide thin film electrode material is a nanosheet structure that is upright on the surface of a porous iron substrate and cross-linked with each other. Figure 3 and Figure 4 The figures show the charge-discharge curves and specific capacity of the electrode material in a 6 mol / L KOH electrolyte solution at different current densities. Clearly, within the range of 50–250 mA / cm², the specific capacity is [not specified]. -2 At current densities, this electrode material exhibits high specific area capacity and high energy density.
[0035] Example 2
[0036] First, the surface of the porous iron substrate is pretreated with acetone, hydrochloric acid, and anhydrous ethanol to clean it, and then dried to obtain a bare porous iron substrate. Second, a reaction solution is prepared, consisting of 15 ml deionized water, 50 g / L KOH, 120 g / L sodium sulfide, and 8 g / L potassium citrate. Then, the reaction solution is placed in a reaction vessel, and the clean porous iron substrate is immersed in the reaction solution, and the reaction vessel is sealed. Next, the reaction vessel is placed in an oven at 220°C for hydrothermal reaction for 12 hours to allow in-situ growth of the porous iron substrate surface. Finally, the hydrothermally treated porous iron substrate is removed, cleaned alternately with deionized water and ethanol, and dried to obtain a high-energy-density iron-based sulfide thin-film electrode material.
[0037] Example 3
[0038] First, the surface of the porous iron substrate is pretreated with acetone, hydrochloric acid, and anhydrous ethanol and then dried to obtain a bare porous iron substrate. Second, a reaction solution is prepared, consisting of 15 ml of deionized water, 60 g / L NaOH, 160 g / L sodium sulfide, and 10 g / L potassium citrate. Then, the reaction solution is placed in a reaction vessel, and the clean porous iron substrate is immersed in the reaction solution, and the reaction vessel is sealed. Next, the reaction vessel is placed in an oven and subjected to a hydrothermal reaction at 150°C for 18 hours to allow in-situ growth of the porous iron substrate surface. Finally, the hydrothermally treated porous iron substrate is removed, cleaned alternately with deionized water and ethanol, and then dried to obtain a high-energy-density iron-based sulfide thin-film electrode material.
[0039] Example 4
[0040] First, the surface of the porous iron substrate is pretreated with acetone, hydrochloric acid, and anhydrous ethanol and then dried to obtain a bare porous iron substrate. Second, a reaction solution is prepared, consisting of 15 ml deionized water, 70 g / L KOH, 200 g / L sodium sulfide, and 12 g / L ammonium citrate. Then, the reaction solution is placed in a reaction vessel, and the clean porous iron substrate is immersed in the reaction solution, and the reaction vessel is sealed. Next, the reaction vessel is placed in an oven and subjected to a hydrothermal reaction at 150°C for 12 hours to allow in-situ growth of the porous iron substrate surface. Finally, the hydrothermally treated porous iron substrate is removed, cleaned alternately with deionized water and ethanol, and then dried to obtain a high-energy-density iron-based sulfide thin-film electrode material.
[0041] Example 5
[0042] First, the surface of the porous iron substrate is pretreated with acetone, hydrochloric acid, and anhydrous ethanol and then dried to obtain a bare porous iron substrate. Second, a reaction solution is prepared, consisting of 15 ml deionized water, 90 g / L KOH, 250 g / L sodium sulfide, and 15 g / L potassium citrate. Then, the reaction solution is placed in a reaction vessel, and the clean porous iron substrate is immersed in the reaction solution, and the reaction vessel is sealed. Next, the reaction vessel is placed in an oven and subjected to a hydrothermal reaction at 180°C for 24 hours to allow in-situ growth of the porous iron substrate surface. Finally, the hydrothermally heated porous iron substrate is removed, cleaned alternately with deionized water and ethanol, and then dried to obtain a high-energy-density iron-based sulfide thin-film electrode material.
[0043] Example 6
[0044] First, the surface of the porous iron substrate is pretreated with acetone, hydrochloric acid, and anhydrous ethanol and then dried to obtain a bare porous iron substrate. Second, a reaction solution is prepared using 15 ml of deionized water, 30 g / L KOH, 30 g / L sodium sulfide, and 10 g / L sodium citrate. Then, the reaction solution is placed in a reaction vessel, and the clean porous iron substrate is immersed in the reaction solution, and the reaction vessel is sealed. Next, the reaction vessel is placed in an oven at 250°C for hydrothermal reaction for 20 hours to allow in-situ growth of the porous iron substrate surface. Finally, the hydrothermally treated porous iron substrate is removed, cleaned alternately with deionized water and ethanol, and dried to obtain a high-energy-density iron-based sulfide thin-film electrode material.
[0045] Example 7
[0046] First, the surface of the porous iron substrate is pretreated with acetone, hydrochloric acid, and anhydrous ethanol and then dried to obtain a bare porous iron substrate. Second, a reaction solution is prepared, consisting of 15 ml deionized water, 100 g / L KOH, 270 g / L sodium sulfide, and 30 g / L ammonium citrate. Then, the reaction solution is placed in a reaction vessel, and the clean porous iron substrate is immersed in the reaction solution, and the reaction vessel is sealed. Next, the reaction vessel is placed in an oven at 200°C for a hydrothermal reaction for 15 hours to allow in-situ growth of the porous iron substrate surface. Finally, the hydrothermally heated porous iron substrate is removed, cleaned alternately with deionized water and ethanol, and then dried to obtain a high-energy-density iron-based sulfide thin-film electrode material.
[0047] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention herein. This invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art. The specification and examples are to be considered exemplary only, and the true scope and spirit of the invention are indicated by the claims.
[0048] It should be understood that the present invention is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.
Claims
1. A high-energy-density iron-based sulfide thin-film electrode, characterized in that, The iron-based sulfide thin film electrode is fabricated by in-situ growth reaction on the surface of a porous iron substrate using a one-step hydrothermal method. The method for preparing the iron-based sulfide thin film electrode includes the following steps: (1) The surface of the porous iron matrix is ultrasonically pretreated with acetone, hydrochloric acid and anhydrous ethanol and then dried to remove impurities; (2) A reaction solution is obtained by mixing deionized water, alkali metal hydroxide, alkali metal sulfide and citrate, wherein the mass ratio of the alkali metal hydroxide, the alkali metal sulfide and the citrate is (30~100): (30~270): (5~30); (3) Immerse the porous iron substrate in the reaction solution and heat it to carry out a hydrothermal reaction, so that the in-situ growth reaction occurs on the surface of the porous iron substrate. (4) Take out the porous iron substrate after hydrothermal treatment, wash it alternately with water and anhydrous ethanol and dry it to obtain the iron-based sulfide thin film electrode material.
2. The iron-based sulfide thin film electrode according to claim 1, characterized in that, The iron-based sulfide thin film electrode has a surface loading of 141 mg / cm². -2 .
3. The iron-based sulfide thin film electrode according to claim 1, characterized in that, The working mechanism of the iron-based sulfide thin film electrode in the alkaline system is 4FeS + 6OH. - 2FeS2 + Fe2O3 + 3H2O + 6e - .
4. The application of the iron-based sulfide thin-film electrode according to any one of claims 1 to 3 in an aqueous battery, characterized in that, The iron-based sulfide thin film electrode serves as the anode material of the aqueous battery.
5. The method for preparing an iron-based sulfide thin film electrode according to any one of claims 1 to 3, characterized in that, Includes the following steps: (1) The surface of the porous iron matrix is ultrasonically pretreated with acetone, hydrochloric acid and anhydrous ethanol and then dried to remove impurities; (2) A reaction solution is obtained by mixing deionized water, alkali metal hydroxide, alkali metal sulfide and citrate, wherein the mass ratio of the alkali metal hydroxide, the alkali metal sulfide and the citrate is (30~100): (30~270): (5~30); (3) Immerse the porous iron substrate in the reaction solution and heat it to carry out a hydrothermal reaction, so that the in-situ growth reaction occurs on the surface of the porous iron substrate. (4) Take out the porous iron substrate after hydrothermal treatment, wash it alternately with water and anhydrous ethanol and dry it to obtain the iron-based sulfide thin film electrode material.
6. The method for preparing an iron-based sulfide thin film electrode according to claim 5, characterized in that, In step (2), the alkali metal hydroxide in the reaction solution is 30~100 g / L, and the alkali metal hydroxide is selected from at least one of KOH and NaOH.
7. The method for preparing an iron-based sulfide thin film electrode according to claim 5, characterized in that, In step (2), the alkali metal sulfide in the reaction solution is 30~270 g / L, and the alkali metal sulfide is selected from sodium sulfide and potassium sulfide.
8. The method for preparing an iron-based sulfide thin film electrode according to claim 5, characterized in that, In step (2), the citrate concentration in the reaction solution is 5-30 g / L, and the citrate is selected from C6H5Na3O7, C6H5K3O7, and C6H 17 One or more of N3O7, C6H5O7(NH4)3, and C6H7NaO7.
9. The method for preparing an iron-based sulfide thin film electrode according to claim 5, characterized in that, In step (3), the temperature of the hydrothermal reaction is 150~250℃ and the time of the hydrothermal reaction is 12~24 h.
10. The method for preparing an iron-based sulfide thin film electrode according to claim 5, characterized in that, In step (3), the in-situ growth reaction uses the porous iron substrate as the iron source and current collector, and the surface of the substrate undergoes in-situ electrochemical preparation to form an active material film, which serves as a self-supporting electrode without binder.