阅读说明：本技术 泡沫钛基底上生长碳包覆铁氧化物纳米棒阵列材料及其制备方法 (Carbon-coated iron oxide nanorod array material grown on foamed titanium substrate and preparation method thereof ) 是由 李睿智 李荣聪 张灵 周盈科 于 2020-11-23 设计创作，主要内容包括：本发明涉及一种泡沫钛基底上生长碳包覆铁氧化物纳米棒阵列材料及其制备方法。其技术方案是：按浓度为0.05～0.10mol/L,将硫酸钠∶六水合氯化铁的摩尔比为1∶1混合后溶于去离子水,在160～170℃水热反应5～7h,洗涤,烘干,在430～480℃和氩气条件下退火2～3h,得到泡沫钛基底上生长铁氧化物纳米棒阵列材料。再浸入1.0～1.5mol/L的葡萄糖水溶液中12～36h,烘干,得到碳包覆铁氧化物前驱体；将碳包覆铁氧化物前驱体置于管式气氛炉中,在混合气氛中升温至630～680℃,保温,冷却,制得泡沫钛基底上生长碳包覆铁氧化物纳米棒阵列材料。本发明工艺简单、操作简便、环境友好和能实现工业化生产,所制制品比容量高、倍率性能好和循环稳定性优异。(The invention relates to a carbon-coated iron oxide nanorod array material growing on a foamed titanium substrate and a preparation method thereof. The technical scheme is as follows: mixing sodium sulfate and ferric chloride hexahydrate according to the molar ratio of 0.05-0.10 mol/L and dissolving in deionized water, carrying out hydrothermal reaction for 5-7 h at 160-170 ℃, washing, drying, and annealing for 2-3 h at 430-480 ℃ under the condition of argon gas to obtain the iron oxide nanorod array material grown on the foamed titanium substrate. Then immersing the carbon-coated iron oxide precursor into 1.0-1.5 mol/L glucose aqueous solution for 12-36 h, and drying to obtain a carbon-coated iron oxide precursor; and (3) placing the carbon-coated iron oxide precursor in a tubular atmosphere furnace, heating to 630-680 ℃ in mixed atmosphere, preserving heat, and cooling to obtain the carbon-coated iron oxide nanorod array material growing on the foamed titanium substrate. The method has the advantages of simple process, simple and convenient operation, environmental protection and capability of realizing industrial production, and the prepared product has high specific capacity, good rate capability and excellent cycle stability.)

1. A preparation method for growing a carbon-coated iron oxide nanorod array material on a titanium foam substrate is characterized by comprising the following steps:

(1) mixing the materials according to the molar ratio of sodium sulfate to ferric chloride hexahydrate of 1: 1 to obtain a mixture; dissolving the mixture into deionized water according to the concentration of 0.05-0.10 mol/L, and stirring at room temperature to obtain a mixed solution;

(2) ultrasonically cleaning titanium foam for 15-30 min by using a detergent, ultrasonically cleaning for 15-30 min by using ethanol and ultrasonically cleaning for 15-30 min by using deionized water in sequence, immersing the cleaned titanium foam into a reaction kettle containing the mixed solution, carrying out hydrothermal reaction for 5-7 h at 160-170 ℃, and naturally cooling to room temperature; washing with deionized water, drying at 60-80 ℃, and annealing for 2-3 h at 430-480 ℃ under the protection of argon gas to obtain the iron oxide nanorod array material grown on the foamed titanium substrate;

(3) immersing the iron oxide nanorod array material growing on the titanium foam substrate into 1.0-1.5 mol/L glucose aqueous solution for 12-36 h, and drying at 60-80 ℃ to obtain a carbon-coated iron oxide precursor;

(4) placing the carbon-coated iron oxide precursor in a tubular atmosphere furnace, heating to 630-680 ℃ at the speed of 5-10 ℃/min in mixed atmosphere, preserving heat for 2-3 h, and cooling to obtain a carbon-coated iron oxide nanorod array material growing on the foamed titanium substrate;

the iron oxide nanorods of the carbon-coated iron oxide nanorod array material grown on the foamed titanium substrate are combined with foamed titanium with a three-dimensional pore structure to form a three-dimensional structure with nested foamed titanium pores and closely-arranged nanorod arrays.

2. The method of claim 1, wherein the sodium sulfate is analytically pure.

3. The method of claim 1, wherein the ferric chloride hexahydrate is analytically pure.

4. The method for preparing the carbon-coated iron oxide nanorod array material grown on the foamed titanium substrate according to claim 1, wherein the foamed titanium is in a strip shape and has a purity of 99.95% or more.

5. The method for preparing carbon-coated iron oxide nanorod array material grown on a titanium foam substrate according to claim 1, wherein the atmosphere is a mixed atmosphere of hydrogen and argon; wherein: 4-6 vol% of hydrogen and 94-96 vol% of argon.

6. A carbon-coated iron oxide nanorod array material grown on a titanium foam substrate, which is characterized in that the carbon-coated iron oxide nanorod array material grown on the titanium foam substrate is the carbon-coated iron oxide nanorod array material grown on the titanium foam substrate prepared by the preparation method of the carbon-coated iron oxide nanorod array material grown on the titanium foam substrate according to any one of claims 1-5.

Technical Field

The invention belongs to the technical field of carbon-coated iron oxide nanorod array composite materials. In particular to a carbon-coated iron oxide nanorod array material grown on a foamed titanium substrate and a preparation method thereof.

Background

The super capacitor is a novel energy storage device between a traditional capacitor and a storage battery, is considered as a renewable clean energy conversion and storage device with the greatest development prospect, has the advantages of high specific energy, wide working temperature range, long service life, good cycle performance, high power density, environmental protection and the like, and is widely applied to the fields of electronic products, the electric automobile industry, aerospace, power storage and the like. Currently, research on electrode materials of supercapacitors mainly includes carbon materials, metal oxides and conductive polymers, wherein the metal oxides are receiving much attention with their high specific capacities.

Iron oxide is currently a promising metal oxide anode material. Has the following advantages: 1. the valence state is multiple, the redox activity is high, and the theoretical capacity is high; 2. a stable and large negative working range is provided; 3. compared with other transition metal oxides, the iron oxide is safe, nontoxic and environment-friendly; 4. iron oxide is widely distributed and cheap (Fe)₂O₃<$1/kg), which is more easily put into commercial production, is just a suitable electrode material we are looking for. However, the activity of iron oxides is dependent on surface or near-surface redox reactions, and their performance is determined by charge transport kinetics, and theoretically predicted high capacitances are rarely obtained in practical experiments. Although the two-dimensional composite modifying method of iron oxide and carbon fiber and other materials has been developed at present, the two-dimensional composite modifying method is to a certain extentThe electrochemical performance of the iron oxide is improved, but the iron oxide is easily agglomerated due to the loading of materials such as carbon fiber and the like, so that the active specific surface is reduced, and the higher and higher performance requirements of the electrode material of the supercapacitor are difficult to meet.

The development of a simple, high specific capacity, and cost-effective method for synthesizing iron oxide materials remains one of the concerns of those skilled in the art.

Document D.B.Jiang, B.Y.ZHang, T.X.ZHENG, Y.X.ZHang, X.xu, One-pot synthesis of eta-Fe₂O₃nanospheres/catalyst compositions for electrochemical capacitor electrodes, mater. Lett.215(2018)23-26, reported that Fe was produced by hydrothermal reaction₂O₃The specific capacity of the nano-sphere negative electrode material is low, and the current density is 1A g^-1The specific capacity was 89.1F g^-1And cycle stability is not very good, at 1.5A g^-1The capacity retention ratio after 1000 cycles was 73.92% at the current density of (1).

' A kind of Fe₂O₃The patent technology of the nanometer rod array electrode in-situ sulfuration and carbon coating (CN 106848301B) uses a titanium sheet as a substrate, and prepares Fe through in-situ sulfuration and coating by a hydrothermal method₂O₃the-S @ C is poor in rate capability, and meanwhile, when carbon coating is carried out, methane is used as a carbon source, so that the environment is influenced.

'growing iron oxide nano-rod array material on foamed titanium substrate and preparation method thereof' (202011261537.5) patent technology, Fe prepared by the technology₂O₃The nanorod array has excellent rate performance, but the capacity of the electrode is quickly attenuated in the circulating process.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and aims to provide a preparation method for growing carbon-coated iron oxide nanorod array material on a foamed titanium substrate, which has the advantages of simple process, convenient operation, environmental protection and easy industrial production.

In order to achieve the purpose, the technical scheme adopted by the invention comprises the following steps:

(1) mixing the materials according to the molar ratio of sodium sulfate to ferric chloride hexahydrate of 1: 1 to obtain a mixture; and dissolving the mixture into deionized water according to the concentration of 0.05-0.10 mol/L, and stirring at room temperature to obtain a mixed solution.

(2) Ultrasonically cleaning titanium foam for 15-30 min by using a detergent, ultrasonically cleaning for 15-30 min by using ethanol and ultrasonically cleaning for 15-30 min by using deionized water in sequence, immersing the cleaned titanium foam into a reaction kettle containing the mixed solution, carrying out hydrothermal reaction for 5-7 h at 160-170 ℃, and naturally cooling to room temperature; and washing with deionized water, drying at 60-80 ℃, and annealing for 2-3 hours at 430-480 ℃ under the protection of argon gas to obtain the iron oxide nanorod array material grown on the foamed titanium substrate.

(3) And (3) immersing the iron oxide nanorod array material grown on the foamed titanium substrate into 1.0-1.5 mol/L glucose aqueous solution for 12-36 h, and drying at 60-80 ℃ to obtain a carbon-coated iron oxide precursor.

(4) And (3) placing the carbon-coated iron oxide precursor in a tubular atmosphere furnace, heating to 630-680 ℃ at the speed of 5-10 ℃/min in mixed atmosphere, preserving heat for 2-3 h, and cooling to obtain the carbon-coated iron oxide nanorod array material growing on the foamed titanium substrate.

The iron oxide nanorods of the carbon-coated iron oxide nanorod array material grown on the foamed titanium substrate are combined with foamed titanium with a three-dimensional pore structure to form a three-dimensional structure with nested foamed titanium pores and closely-arranged nanorod arrays.

The sodium sulfate is analytically pure.

The ferric chloride hexahydrate is analytically pure.

The foamed titanium is in a strip shape, and the purity of the foamed titanium is more than 99.95%.

The atmosphere is a mixed atmosphere of hydrogen and argon; wherein: 4-6 vol% of hydrogen and 94-96 vol% of argon.

Due to the adoption of the technical scheme, compared with the prior art, the invention has the following beneficial effects:

(1) ultrasonically cleaning foamed titanium by using detergent, ethanol and deionized water in sequence, carrying out hydrothermal reaction for 5-7 h at 160-170 ℃, and carrying out argon heat treatment to obtain an iron oxide nanorod array material growing on a foamed titanium substrate; then the iron oxide nanorod array material growing on the titanium foam substrate is immersed in a glucose aqueous solution, dried and subjected to heat treatment to obtain the carbon-coated iron oxide nanorod array material growing on the titanium foam substrate, so that the process is simple.

(2) The invention has no toxic gas release in the reaction process, and the Na discharged after the reaction is finished₂SO₄And FeCl₃·6H₂The mixed waste liquid of O has little pollution to the environment and is green and environment-friendly. The iron source and the carbon source for preparing the carbon-coated iron oxide have low price, the equipment required by the production process is simple, and the production cost is low.

(3) The iron oxide nanorods in the carbon-coated iron oxide nanorod array material grown on the foamed titanium substrate prepared by the invention are closely arranged on the substrate. Firstly, the contact area of unit mass electrode/electrolyte can be increased by material nanocrystallization, so that more reaction sites are generated, secondly, the ordered nanorod array structure is most effective in the aspect of reaction kinetics, and the provided rapid and direct electron transport channel can shorten the transport path of electrolyte ions and electrons, so that larger capacitance and higher rate performance are obtained.

(4) Iron oxide nanorods in the carbon-coated iron oxide nanorod array material grown on the foamed titanium substrate prepared by the invention are combined with three-dimensional hole foamed titanium to form a three-dimensional material formed by nesting and growing the iron oxide nanorod array and the foamed titanium substrate. The three-dimensional porous structure can greatly improve the loading capacity of active substances in unit area, improve the specific capacity of the carbon-coated iron oxide nanorod array material grown on the titanium foam substrate, and meanwhile, the porous structure can accelerate the permeation of electrolyte and shorten an ion transmission channel, so that the active surface area of the active material in contact with the electrolyte is increased. However, in alkaline electrolytes, binderless iron oxide matricesComplete redox reaction (Fe) in the course of a cycle³⁺→Fe²⁺→Fe⁰) It is more fragile and results in rapid structural failure. Therefore, the carbon coating is adopted for coating, the carbon layer not only improves the conductivity of the electrode, but also can effectively buffer the volume expansion caused by the deformation of the structure and reduce the agglomeration and stacking of the iron oxide nanorod array in the electrochemical process, and is beneficial to keeping the integration of the nanorod array, thereby further improving the specific capacity, the multiplying power and the cycle performance of the iron oxide.

(5) The carbon-coated iron oxide nanorod array material grown on the foamed titanium substrate prepared by the invention is detected as follows: the aperture of the titanium foam is 20-25 mu m, and the iron oxide nanorods are uniformly distributed on the surface layer and in the holes of the titanium foam.

The carbon-coated iron oxide nanorod array material grown on the foamed titanium substrate prepared by the invention is tested by electrochemical performance: at a sweep rate of 1mVs^-1The specific capacity is 4.997-7.017 Fcm^-2(ii) a At a sweep rate of 5mVs^-1The specific capacity is 2.061-4.259 Fcm^-2(ii) a At a sweep rate of 100mVs^-1The specific capacity is 0.694-1.230 Fcm^-2；50mVs^-1After 5000 cycles, the capacity value retention rate reaches 88-92%.

Therefore, the method has the characteristics of simple process, simple and convenient operation, environmental friendliness and capability of realizing industrial production, and the prepared carbon-coated iron oxide nanorod array material grown on the foamed titanium substrate has high specific capacity, good rate capability, excellent conductivity and remarkably improved cycling stability.

Drawings

FIG. 1 is an XRD pattern of a carbon-coated iron oxide nanorod array material grown on a titanium foam substrate prepared by the present invention;

FIG. 2 is an SEM image of a carbon-coated iron oxide nanorod array material grown on the titanium foam substrate shown in FIG. 1;

FIG. 3 is a TEM image of the carbon-coated iron oxide nanorod array material grown on the titanium foam substrate shown in FIG. 1;

FIG. 4 is a graph of the electrochemical performance of three electrodes of the carbon-coated iron oxide nanorod array material grown on the titanium foam substrate shown in FIG. 1;

FIG. 5 is a graph of the cycling performance of the growth of carbon-coated iron oxide nanorod array material on the titanium foam substrate of FIG. 1;

Detailed Description

The invention is further described with reference to the following drawings and detailed description, but the invention is not limited to the scope of the claims.

A carbon-coated iron oxide nanorod array material growing on a titanium foam substrate and a preparation method thereof. The preparation method of the specific embodiment comprises the following steps:

(1) mixing the materials according to the molar ratio of sodium sulfate to ferric chloride hexahydrate of 1: 1 to obtain a mixture; and dissolving the mixture into deionized water according to the concentration of 0.05-0.10 mol/L, and stirring at room temperature to obtain a mixed solution.

(2) Ultrasonically cleaning titanium foam for 15-30 min by using a detergent, ultrasonically cleaning for 15-30 min by using ethanol and ultrasonically cleaning for 15-30 min by using deionized water in sequence, immersing the cleaned titanium foam into a reaction kettle containing the mixed solution, carrying out hydrothermal reaction for 5-7 h at 160-170 ℃, and naturally cooling to room temperature; and washing with deionized water, drying at 60-80 ℃, and annealing for 2-3 hours at 430-480 ℃ under the protection of argon gas to obtain the iron oxide nanorod array material grown on the foamed titanium substrate.

(3) And (3) immersing the iron oxide nanorod array material grown on the foamed titanium substrate into 1.0-1.5 mol/L glucose aqueous solution for 12-36 h, and drying at 60-80 ℃ to obtain a carbon-coated iron oxide precursor.

(4) And (3) placing the carbon-coated iron oxide precursor in a tubular atmosphere furnace, heating to 630-680 ℃ at the speed of 5-10 ℃/min in mixed atmosphere, preserving heat for 2-3 h, and cooling to obtain the carbon-coated iron oxide nanorod array material growing on the foamed titanium substrate.

The atmosphere is a mixed atmosphere of hydrogen and argon; wherein: 4-6 vol% of hydrogen and 94-96 vol% of argon.

In this embodiment:

the carbon-coated iron oxide nanorod array material grown on the titanium foam substrate prepared by the specific embodiment is detected as follows: the aperture of the titanium foam is 20-25 μm, and the iron oxide nanorods are uniformly distributed on the surface layer and in the holes of the titanium foam.

The iron oxide nanorods of the carbon-coated iron oxide nanorod array material grown on the foamed titanium substrate are combined with foamed titanium with a three-dimensional pore structure to form a three-dimensional structure with nested foamed titanium pores and closely-arranged nanorod arrays.

The sodium sulfate is analytically pure.

The ferric chloride hexahydrate is analytically pure.

The foamed titanium is in a strip shape, and the purity of the foamed titanium is more than 99.95%.

The detailed description is omitted in the embodiments.

Example 1

A carbon-coated iron oxide nanorod array material growing on a titanium foam substrate and a preparation method thereof. The preparation method of the embodiment comprises the following specific steps:

(1) mixing the materials according to the molar ratio of sodium sulfate to ferric chloride hexahydrate of 1: 1 to obtain a mixture; and dissolving the mixture into deionized water according to the concentration of 0.075mol/L, and stirring at room temperature to obtain a mixed solution.

(2) Ultrasonically cleaning titanium foam for 15min by using detergent, ultrasonically cleaning for 20min by using ethanol and ultrasonically cleaning for 25min by using deionized water in sequence, immersing the cleaned titanium foam into a reaction kettle containing the mixed solution, carrying out hydrothermal reaction for 6h at 165 ℃, and naturally cooling to room temperature; and washing with deionized water, drying at 80 ℃, and annealing for 2 hours at 450 ℃ under the protection of argon gas to obtain the iron oxide nanorod array material growing on the foamed titanium substrate.

(3) And (3) immersing the iron oxide nanorod array material grown on the foamed titanium substrate into 1.2mol/L glucose aqueous solution for 24h, and drying at 80 ℃ to obtain a carbon-coated iron oxide precursor.

(4) And (3) placing the carbon-coated iron oxide precursor in a tubular atmosphere furnace, heating to 650 ℃ at the speed of 5 ℃/min in mixed atmosphere, preserving heat for 2h, and cooling to obtain the carbon-coated iron oxide nanorod array material growing on the foamed titanium substrate.

The atmosphere is a mixed atmosphere of hydrogen and argon; wherein: hydrogen was 4 vol% and argon was 96 vol%.

The carbon-coated iron oxide nanorod array material grown on the foamed titanium substrate prepared by the experiment is detected as follows: the aperture of the titanium foam is 20 μm, and the iron oxide nanorods are uniformly distributed on the surface layer and in the holes of the titanium foam.

The carbon-coated iron oxide nanorod array material grown on the titanium foam substrate prepared in the embodiment is shown in fig. 4 after being subjected to electrochemical performance tests: at a sweep rate of 1mVs^-1Specific capacity of 7.017Fcm^-2(ii) a At a sweep rate of 5mVs^-1Specific capacity of 4.259Fcm^-2(ii) a At a sweep rate of 100mVs^-1Specific capacity of 1.230Fcm^-2；50mVs^-1After 5000 cycles, the capacity value retention rate reaches 92%.

Example 2

A carbon-coated iron oxide nanorod array material growing on a titanium foam substrate and a preparation method thereof. The preparation method of the embodiment comprises the following specific steps:

(1) mixing the materials according to the molar ratio of sodium sulfate to ferric chloride hexahydrate of 1: 1 to obtain a mixture; and dissolving the mixture into deionized water according to the concentration of 0.05mol/L, and stirring at room temperature to obtain a mixed solution.

(2) Ultrasonically cleaning titanium foam for 30min by using a detergent, ultrasonically cleaning for 15min by using ethanol and ultrasonically cleaning for 20min by using deionized water in sequence, immersing the cleaned titanium foam into a reaction kettle containing the mixed solution, carrying out hydrothermal reaction for 5h at 170 ℃, and naturally cooling to room temperature; and washing with deionized water, drying at 60 ℃, and annealing for 3 hours under the protection of argon at 430 ℃ to obtain the iron oxide nanorod array material grown on the foamed titanium substrate.

(3) And (3) immersing the iron oxide nanorod array material grown on the foamed titanium substrate into 1.0mol/L glucose aqueous solution for 36h, and drying at 60 ℃ to obtain a carbon-coated iron oxide precursor.

(4) And (3) placing the carbon-coated iron oxide precursor in a tubular atmosphere furnace, heating to 630 ℃ at the speed of 8 ℃/min in mixed atmosphere, preserving heat for 3h, and cooling to obtain the carbon-coated iron oxide nanorod array material growing on the foamed titanium substrate.

The atmosphere is a mixed atmosphere of hydrogen and argon; wherein: hydrogen was 5 vol% and argon was 95 vol%.

The carbon-coated iron oxide nanorod array material grown on the foamed titanium substrate prepared by the experiment is detected as follows: the aperture of the titanium foam is 22 μm, and the iron oxide nanorods are uniformly distributed on the surface layer and in the holes of the titanium foam.

The carbon-coated iron oxide nanorod array material grown on the foamed titanium substrate prepared in the embodiment is tested for electrochemical performance: at a sweep rate of 1mVs^-1Specific capacity of 4.997Fcm^-2(ii) a At a sweep rate of 5mVs^-1Specific capacity of 2.061Fcm^-2(ii) a At a sweep rate of 100mVs^-1Specific capacity of 0.694Fcm^-2；50mVs^-1After 5000 cycles, the capacity value retention rate reaches 89%.

Example 3

A carbon-coated iron oxide nanorod array material grown on a titanium foam substrate. The preparation method of the embodiment comprises the following specific steps:

(1) mixing the materials according to the molar ratio of sodium sulfate to ferric chloride hexahydrate of 1: 1 to obtain a mixture; and dissolving the mixture into deionized water according to the concentration of 0.06mol/L, and stirring at room temperature to obtain a mixed solution.

(2) Ultrasonically cleaning titanium foam for 20min by using detergent, ultrasonically cleaning for 25min by using ethanol and ultrasonically cleaning for 30min by using deionized water in sequence, immersing the cleaned titanium foam into a reaction kettle containing the mixed solution, carrying out hydrothermal reaction for 6h at 160 ℃, and naturally cooling to room temperature; and washing with deionized water, drying at 70 ℃, and annealing for 2 hours at 460 ℃ under the protection of argon gas to obtain the iron oxide nanorod array material growing on the foamed titanium substrate.

(3) And (3) immersing the iron oxide nanorod array material grown on the foamed titanium substrate into 1.2mol/L glucose aqueous solution for 36h, and drying at 70 ℃ to obtain a carbon-coated iron oxide precursor.

(4) And (3) placing the carbon-coated iron oxide precursor in a tubular atmosphere furnace, heating to 640 ℃ at the speed of 7 ℃/min in mixed atmosphere, preserving heat for 3h, and cooling to obtain the carbon-coated iron oxide nanorod array material growing on the foamed titanium substrate.

The atmosphere is a mixed atmosphere of hydrogen and argon; wherein: 6 vol% of hydrogen and 94 vol% of argon.

The carbon-coated iron oxide nanorod array material grown on the foamed titanium substrate prepared by the experiment is detected as follows: the aperture of the titanium foam is 25 μm, and the iron oxide nanorods are uniformly distributed on the surface layer and in the holes of the titanium foam.

The carbon-coated iron oxide nanorod array material grown on the foamed titanium substrate prepared in the embodiment is tested for electrochemical performance: at a sweep rate of 1mVs^-1Specific capacity of 5.748Fcm^-2(ii) a At a sweep rate of 5mVs^-1Specific capacity of 3.48Fcm^-2(ii) a At a sweep rate of 100mVs^-1Specific capacity of 1.007Fcm^-2；50mVs^-1After 5000 cycles, the capacity value retention rate reaches 90%.

Example 4

A carbon-coated iron oxide nanorod array material grown on a titanium foam substrate. The preparation method of the embodiment comprises the following specific steps:

(1) mixing the materials according to the molar ratio of sodium sulfate to ferric chloride hexahydrate of 1: 1 to obtain a mixture; and dissolving the mixture into deionized water according to the concentration of 0.10mol/L, and stirring at room temperature to obtain a mixed solution.

(2) Ultrasonically cleaning titanium foam for 25min by using detergent, ultrasonically cleaning for 30min by using ethanol and ultrasonically cleaning for 15min by using deionized water in sequence, immersing the cleaned titanium foam into a reaction kettle containing the mixed solution, carrying out hydrothermal reaction for 7h at 165 ℃, and naturally cooling to room temperature; and washing with deionized water, drying at 80 ℃, and annealing for 2 hours at 480 ℃ under the protection of argon gas to obtain the iron oxide nanorod array material growing on the foamed titanium substrate.

(3) And (3) immersing the iron oxide nanorod array material grown on the foamed titanium substrate into 1.5mol/L glucose aqueous solution for 12h, and drying at 80 ℃ to obtain a carbon-coated iron oxide precursor.

(4) And (3) placing the carbon-coated iron oxide precursor in a tubular atmosphere furnace, heating to 680 ℃ at the speed of 10 ℃/min in mixed atmosphere, preserving heat for 2h, and cooling to obtain the carbon-coated iron oxide nanorod array material growing on the foamed titanium substrate.

The atmosphere is a mixed atmosphere of hydrogen and argon; wherein: hydrogen was 5 vol% and argon was 95 vol%.

The carbon-coated iron oxide nanorod array material grown on the foamed titanium substrate prepared by the experiment is detected as follows: the aperture of the titanium foam is 23 μm, and the iron oxide nanorods are uniformly distributed on the surface layer and in the holes of the titanium foam.

The carbon-coated iron oxide nanorod array material grown on the foamed titanium substrate prepared in the embodiment is tested for electrochemical performance: at a sweep rate of 1mVs^-1Specific capacity of 6.895Fcm^-2(ii) a At a sweep rate of 5mVs^-1Specific capacity of 3.674Fcm^-2(ii) a At a sweep rate of 100mVs^-1Specific capacity of 1.190Fcm^-2；50mVs^-1After 5000 cycles, the capacity value retention rate reaches 88%.

Compared with the prior art, the beneficial effects of the specific implementation mode are as follows:

(1) the method comprises the following steps of ultrasonically cleaning foamed titanium by using detergent, ethanol and deionized water in sequence, carrying out hydrothermal reaction for 5-7 h at 160-170 ℃, and carrying out argon heat treatment to obtain an iron oxide nanorod array material growing on a foamed titanium substrate; then the iron oxide nanorod array material growing on the titanium foam substrate is immersed in a glucose aqueous solution, dried and subjected to heat treatment to obtain the carbon-coated iron oxide nanorod array material growing on the titanium foam substrate, so that the process is simple.

(2) The specific embodiment has no toxic gas release in the reaction process, and the Na discharged after the reaction is finished₂SO₄And FeCl₃·6H₂The mixed waste liquid of O has little pollution to the environment and is green and environment-friendly. Iron source for producing carbon-coated iron oxide andthe carbon source has low price, the equipment required by the production process is simple, and the production cost is low.

(3) The iron oxide nanorods in the carbon-coated iron oxide nanorod array material grown on the titanium foam substrate prepared by the specific embodiment are closely arranged on the substrate. Firstly, the contact area of unit mass electrode/electrolyte can be increased by material nanocrystallization, so that more reaction sites are generated, secondly, the ordered nanorod array structure is most effective in the aspect of reaction kinetics, and the provided rapid and direct electron transport channel can shorten the transport path of electrolyte ions and electrons, so that larger capacitance and higher rate performance are obtained.

(4) The carbon-coated iron oxide nanorod array material grown on the titanium foam substrate prepared in the present embodiment is shown in the attached drawing, and fig. 1 is an XRD pattern of the carbon-coated iron oxide nanorod array material grown on the titanium foam substrate prepared in example 1; FIG. 2 is an SEM image of a carbon-coated iron oxide nanorod array material grown on the titanium foam substrate shown in FIG. 1; FIG. 3 is a TEM image of the carbon-coated iron oxide nanorod array material grown on the titanium foam substrate shown in FIG. 1; FIG. 4 is a graph of the electrochemical performance of three electrodes of the carbon-coated iron oxide nanorod array material grown on the titanium foam substrate shown in FIG. 1; FIG. 5 is a graph of the cycling performance of the carbon-coated iron oxide nanorod array material grown on the titanium foam substrate of FIG. 1. As can be seen from FIG. 1, the product is Fe₂O₃Successful coating of the material (PDF #39-0238) and carbon element; as can be seen from FIGS. 2 and 3, the iron oxide nanorod arrays in the product are grown on the titanium foam substrate in a closely ordered manner, and the carbon material is uniformly coated on the surface of the nanorod arrays. As can be seen from FIG. 4, as the sweep rate increases, the distance between the oxidation peak and the reduction peak gradually increases, but the shape of the curve is basically maintained, which indicates that the electrode redox reaction process has higher coulombic efficiency and good reversibility; as can be seen from FIG. 5, 50mVs^-1After 5000 cycles, the capacity value retention rate reaches 92%, and the cycle stability is obviously improved.

The iron oxide nanorods in the carbon-coated iron oxide nanorod array material grow on the titanium foam substrate prepared by the specific embodimentAnd combining with the three-dimensional hole titanium foam to form the three-dimensional material formed by nesting and growing the iron oxide nanorod array and the titanium foam substrate. The three-dimensional porous structure can greatly improve the loading capacity of active substances in unit area, improve the specific capacity of the carbon-coated iron oxide nanorod array material grown on the titanium foam substrate, and meanwhile, the porous structure can accelerate the permeation of electrolyte and shorten an ion transmission channel, so that the active surface area of the active material in contact with the electrolyte is increased. However, in alkaline electrolytes, binderless iron oxide arrays undergo complete redox reactions (Fe) during cycling³⁺→Fe²⁺→Fe⁰) It is more fragile and results in rapid structural failure. Therefore, the carbon coating is adopted for coating, the carbon layer not only improves the conductivity of the electrode, but also can effectively buffer the volume expansion caused by the deformation of the structure and reduce the agglomeration and stacking of the iron oxide nanorod array in the electrochemical process, and is beneficial to keeping the integration of the nanorod array, thereby further improving the specific capacity, the multiplying power and the cycle performance of the iron oxide.

(5) The carbon-coated iron oxide nanorod array material grown on the titanium foam substrate prepared by the specific embodiment is detected as follows: the aperture of the titanium foam is 20-25 mu m, and the iron oxide nanorods are uniformly distributed on the surface layer and in the holes of the titanium foam.

The carbon-coated iron oxide nanorod array material grown on the titanium foam substrate prepared by the specific embodiment is tested by electrochemical performance: at a sweep rate of 1mVs^-1The specific capacity is 4.997-7.017 Fcm^-2(ii) a At a sweep rate of 5mVs^-1The specific capacity is 2.061-4.259 Fcm^-2(ii) a At a sweep rate of 100mVs^-1The specific capacity is 0.694-1.230 Fcm^-2；50mVs^-1After 5000 cycles, the capacity value retention rate reaches 88-92%.

Therefore, the specific implementation mode has the characteristics of simple process, simple and convenient operation, environmental friendliness and capability of realizing industrial production, and the prepared carbon-coated iron oxide nanorod array material grown on the foamed titanium substrate has high specific capacity, good rate capability, excellent conductivity and remarkably improved cycling stability.