阅读说明：本技术 一种氧化铁纳米管材料及其制备方法 (Iron oxide nanotube material and preparation method thereof ) 是由 赵卫民 林红 刘永 孙建勇 闫福东 于 2020-03-31 设计创作，主要内容包括：本发明涉及纳米复合材料制备领域,特别公开了一种氧化铁纳米管材料及其制备方法。该氧化铁纳米管材料,其特征在于：以β-FeOOH纳米棒为原料,通过多酸刻蚀得到β-FeOOH纳米管,β-FeOOH纳米管再经加热转化得到形貌稳定的氧化铁纳米管,该氧化铁纳米管表面呈中空管状。本发明的氧化铁纳米管材料是纳米级管状材料,具有容量高、循环性能良好的特地,其制备方法具有成本低、工艺流程简单、反应条件温和以及利用大规模生产的特点。(The invention relates to the field of nano composite material preparation, and particularly discloses an iron oxide nanotube material and a preparation method thereof.)

1. An iron oxide nanotube material is characterized in that β -FeOOH nanorods are used as raw materials, a β -FeOOH nanotube is obtained through polyacid etching, the β -FeOOH nanotube is heated and transformed to obtain the iron oxide nanotube with stable appearance, and the surface of the iron oxide nanotube is in a hollow tubular shape.

2. The method for preparing the iron oxide nanotube material of claim 1, wherein β -FeOOH nanorods are first etched by phosphotungstic acid to form β -FeOOH nanotubes, and then β -FeOOH nanotubes are heated in air at 250 ℃ for 2 hours by controlling the heating temperature to form pure phase iron oxide nanotubes.

3. The method for producing an iron oxide nanotube material according to claim 2, characterized in that: the etching reaction temperature of the phosphotungstic acid is 80 ℃, the reaction time is 1h, and the reaction temperature rise rate is 2 ℃/min.

4. The method for preparing an iron oxide nanotube material of claim 2, wherein the heating rate of the β -FeOOH nanotube is 1-5 ℃/min.

5. The method for preparing an iron oxide nanotube material of claim 2, wherein 1.622g of ferric chloride is added into 25m L distilled water, concentrated hydrochloric acid of 100 μ L is added, 43mg of phosphotungstic acid is added and stirred uniformly, the mixture is placed in a reaction kettle for heating, after cooling and centrifugation, the mixture is repeatedly washed by ultrapure water and ethanol, and dried to obtain β -FeOOH nanotube solid.

6. The method for preparing an iron oxide nanotube material of claim 2, wherein 50mg of β -FeOOH nanotubes are placed in a muffle furnace for heating, and after cooling, the black product is obtained by repeatedly washing with distilled water and ethanol and filtering.

(I) technical field

The invention relates to the field of preparation of nano composite materials, in particular to an iron oxide nano tube material and a preparation method thereof.

(II) background of the invention

With the increasing environmental problems, people are eagerly looking for sustainable energy sources to meet the increasing economic requirements. Lithium ion batteries have attracted much attention because of their advantages of long cycle life, high energy density, low self-discharge, and environmental friendliness. The negative electrode material in the lithium ion battery is mainly commercial graphite, but in recent years, the graphite negative electrode is continuously improved, so that the capacity of storing lithium ions is closer to the theoretical capacity of 372 mAh/g. Since improvement of the graphite negative electrode material is difficult to make a breakthrough, people are looking at transition metal oxides with high specific capacity and excellent safety performance.

In order to improve the electrochemical performance of the materials, ① negative pole materials are compounded, namely the electrochemical performance of the electrodes is improved by introducing substances with good conductivity and small volume effect, ② active materials are nanocrystallized, namely the volume structure change of the materials in the charging and discharging process is effectively relieved due to the fact that the micro size of the nano materials is small, the high specific surface area not only enhances the lithium ion intercalation activity, but also can obtain high rate capacity.

Fe in transition metal oxides₂O₃As a cathode material, the material has the theoretical capacity of 1005mAh/g, rich raw materials and low cost, and can be used for Fe₂O₃The modification and improvement of the method have wide research prospects.

Disclosure of the invention

In order to make up for the defects of the prior art, the invention provides the iron oxide nanotube material which is simple and feasible in reaction, low in cost and suitable for industrial production and the preparation method thereof.

The invention is realized by the following technical scheme:

an iron oxide nanotube material is characterized in that β -FeOOH nanorods are used as raw materials, a β -FeOOH nanotube is obtained through polyacid etching, the β -FeOOH nanotube is heated and transformed to obtain the iron oxide nanotube with stable appearance, and the surface of the iron oxide nanotube is in a hollow tubular shape.

The invention is formed by etching with heated polyacidβ -FeOOH porous nanotube to obtain Fe keeping nanotube morphology₂O₃The nanotube material solves the problems of low specific capacity and poor cycling stability of the traditional anode material and is Fe₂O₃The popularization and the application of the nanotube negative electrode material lay a foundation.

Based on the inventive concept, the preparation method of the iron oxide nanotube material comprises the steps of firstly etching β -FeOOH nanorods by utilizing phosphotungstic acid to form β -FeOOH nanotubes, and secondly heating the β -FeOOH nanotubes in the air at the temperature of 250 ℃ and under the condition of heat preservation for 2 hours by controlling the heating temperature to form the pure-phase iron oxide nanotubes.

The more preferable technical scheme of the invention is as follows:

the etching reaction temperature of the phosphotungstic acid is 80 ℃, the reaction time is 1h, and the reaction temperature rise rate is 2 ℃/min.

The heating rate of the β -FeOOH nanotube is 1-5 ℃/min, the heating reaction temperature is too high, the nanotube framework is easy to collapse, and the temperature is too low, so that the β -FeOOH nanotube cannot be fully converted into an iron oxide nanotube material.

Further, the more specific reaction steps of the invention are:

adding 1.622g of ferric chloride into 25m L distilled water, adding 100 mu L of concentrated hydrochloric acid to prevent hydrolysis, adding 43mg of phosphotungstic acid, uniformly stirring, placing in a reaction kettle, heating, cooling, centrifuging, repeatedly washing with ultrapure water and ethanol, and drying to obtain a β -FeOOH nanotube solid;

and (3) putting 50mg of β -FeOOH nanotube into a muffle furnace for heating, cooling, repeatedly cleaning with distilled water and ethanol, and filtering to obtain a black product.

The method has the advantages that the iron-based nanotube can be controllably generated by adjusting the polyacid, the framework supporting the iron ions can still keep the stability of the morphology after aerobic combustion, and the obtained iron oxide nanotube has good uniformity and stability and is beneficial to the improvement of the electrochemical performance; the iron oxide nanotube material is a nano-scale tubular material, has the characteristics of high capacity and good cycle performance, and the preparation method has the characteristics of low cost, simple process flow, mild reaction conditions and large-scale production.

(IV) description of the drawings

The invention will be further described with reference to the accompanying drawings.

FIG. 1 is a thermogravimetric plot of β -FeOOH nanotubes of the present invention;

FIG. 2 is a single crystal X-ray diffraction pattern of an iron oxide nanotube material of the present invention;

FIG. 3 is a conventional scanning electron microscope map of an iron oxide nanotube material of the present invention;

FIG. 4 is an elemental analysis spectrum of an iron oxide nanotube material according to the present invention;

FIG. 5 is a graph of rate capability of iron oxide nanotube material of the present invention.

(V) detailed description of the preferred embodiments

For a better understanding and practice, the invention is described in detail below with reference to the accompanying drawings.

The inventor finds that the development of the capacity of the carbon negative electrode material with wide application is in a bottleneck period when researching the negative electrode material of the lithium ion battery, and needs to further develop a novel negative electrode material. Thus, the applicant conducted experiments on Fe₂O₃The research shows that the lithium ion material has very high theoretical lithium storage capacity, but the excessive volume change in the reaction process causes the lithium ion material to be easily cracked and pulverized, which greatly influences the application of the lithium ion material in electrochemistry. Researches show that the volume structure change of the material in the charging and discharging processes is effectively relieved due to the small microscopic size of the nano material.

Furthermore, the inventor utilizes the acidity of phosphotungstic acid to controllably regulate and generate β -FeOOH nano-tubes, and heats β -FeOOH nano-tubes in an aerobic manner to convert the nano-tubes into Fe by controlling the temperature₂O₃A nanotube. The preparation method of the nano material has the characteristics of low cost, simple process flow, mild reaction conditions and contribution to large-scale popularization.

The invention provides Fe₂O₃Nanotube material based on Fe₂O₃The structure of the nanotube material is further researched to obtain the Fe of the invention₂O₃A method for preparing a nanotube material. The following examples are further illustrative in detail. The preparation method of the iron oxide nanotube material comprises the following steps:

(1) preparing β -FeOOH porous nano-tube induced by phosphotungstic acid by mixing 1.622g FeCl₃Adding 25m L distilled water, adding 100 mu L of HCl to prevent hydrolysis, adding 43mg of phosphotungstic acid, uniformly stirring, putting into a reaction kettle, heating, cooling, centrifuging, repeatedly cleaning with ultrapure water and ethanol, and drying to obtain a solid;

(2) preparation of Fe₂O₃Nanotube material: taking 50mg of the sample prepared in the S1 step, putting the sample into a muffle furnace for heating, cooling, repeatedly washing with distilled water and ethanol, and filtering to obtain a black sample.