CN108598378B

CN108598378B - Lithium/sodium ion battery negative electrode material Fe1-xPreparation method of S/C

Info

Publication number: CN108598378B
Application number: CN201810082311.5A
Authority: CN
Inventors: 何文; 闫珍珍; 张旭东
Original assignee: Qilu University of Technology
Current assignee: SUZHOU MAOKAI TECHNOLOGY Co.,Ltd.
Priority date: 2018-01-29
Filing date: 2018-01-29
Publication date: 2020-10-02
Anticipated expiration: 2038-01-29
Also published as: CN108598378A

Abstract

The invention provides a lithium/sodium ion battery cathode material Fe_1‑xThe preparation method of the S/C comprises the following steps: carrying out oxidation reaction on the sulfur-containing petroleum sewage and an oxidant to obtain pretreated sulfur-containing petroleum sewage; adding a ferric salt water solution and an additive into the pretreated sulfur-containing petroleum sewage to enable the pH value to be 2-5, and uniformly mixing; then carrying out hydrothermal treatment at the temperature of 150 ℃ and 220 ℃ for 10-48h, and obtaining a precursor through separation, washing, drying and grinding; the obtained precursor is calcined for 5-12h at the temperature of 300-400 ℃ and 800 ℃ under the protection of inert gas, thus obtaining the catalyst. The method of the invention uses the industrial waste sulfur-containing petroleum sewage as the main raw material, has simple method and low cost, and realizes the effective reuse of waste resources; the prepared cathode material has excellent electrochemical performance and high specific discharge capacity.

Description

Lithium/sodium ion battery negative electrode material Fe1-xPreparation method of S/C

Technical Field

The invention relates to a lithium/sodium ion battery cathode material Fe_1-xA preparation method of S/C belongs to the technical field of lithium/sodium ion battery cathode materials.

Background

The high capacity and environmental friendliness of iron-based materials makes them applicable to lithium-ion or sodium-ion batteries. The practical use of iron-based materials is still limited by the rapid capacity fade because the severe expansion of volume during ion intercalation/deintercalation causes the iron-based material structure to collapse, thereby shortening its cycle life. In order to solve the problem and improve the electrochemical performance, an iron-based material and carbon are compounded to form a nanoscale carbon composite material, for example: graphene/Fe₃O₄、Fe_1-xS/C, FeS/C and Fe₃O₄and/C, etc. These carbons can regulate Li⁺/Na⁺The volume expansion caused during the insertion/extraction process increases the electric conductivity thereof, thereby improving the electrochemical properties of the iron-based negative electrode material.

The pyrrhotite belongs to a hexagonal crystal system, the crystal form is in a hexagonal plate shape, and the pyrrhotite has conductivity and magnetism, and part of Fe²⁺Quilt Fe³⁺Instead, to maintain electrovalence balance, in Fe²⁺The occurrence of vacancies in the positions is known as the "absent" structure, so the general formula of pyrrhotite is often Fe_1-xS represents, wherein x represents the defect number (structure) of Fe atomVacancy), typically x is 0 to 0.223. Fe_1-xS is used as an electrode material, has the characteristics of high theoretical capacity, highly reversible redox property, abundant natural resources, environmental friendliness and the like, and is one of novel cathode materials with great potential. Currently, there are few reports on the research in the field of battery materials. Li et al (Large-scalesyntheses of highly unifomm Fe_1-xS nanostrucrures as a high-rate anode for sodium batteries, Nano energy, S2211-2855(2017)30284-7) by a vulcanization method, Fe is firstly synthesized₃O₄Mixing the precursor with thioacetamide and sulfurizing at high temp to obtain Fe_1-xS, at a current density of 0.1mA g^-1Specific discharge capacity of 563mAh g^-1But has the problems of lower specific capacity, low conductivity, fast capacity attenuation in the circulating process, large volume expansion rate, high raw material cost and the like. At present, the stability is improved and the volume expansion rate is reduced mainly by carbon coating or designing into an ideal nanometer structure. Wang et al (Fe)_1-xS/C nanocomposites from sugar cane for high-performance sugar bases Green Chemistry 2016,18,3029-_1-xS is compounded to obtain Fe_1-xS/C composite material in 0.3Ag^-1The specific capacity of the first discharge under the current density is 959mAh g^-1Decaying to 333mAh g after 40 times of circulation^-1Thus, it can be seen that the above-mentioned Fe_1-xThe electrochemical performance of the S/C composite material is still to be improved, the capacity of the electrode material is attenuated quickly, and the method has the advantages of complex preparation process, high raw material cost and serious pollution.

The petroleum sewage mainly comprises petroleum exploitation wastewater, oil refining wastewater and petrochemical wastewater. Wherein the wastewater discharged from the oil refinery is mainly divided into oil-containing petroleum wastewater, sulfur-containing petroleum wastewater and alkali-containing petroleum wastewater. The sulfur-containing petroleum sewage is purple red with strong odor, the main components of the sulfur-containing petroleum sewage are sulfide, ammonia, oil, volatile phenol and other substances, the pollution degree is high, and the wastewater treatment is difficult.

The present invention has been made to solve the above problems.

Disclosure of Invention

The invention provides a lithium/sodium ion battery cathode material Fe with good electrochemical performance_1-xThe preparation method of S/C, said method utilizes the industrial waste sulfur-containing petroleum sewage as the main raw material, the method is simple, with low costs, has realized the effective reuse of the waste resource; the prepared cathode material has excellent electrochemical performance and high specific discharge capacity.

Description of terms:

lithium/sodium ion battery negative electrode material Fe_1-xS/C: is Fe_1-xComposite of S and C, wherein Fe_1-xS is a general formula of pyrrhotite, wherein x represents the defect number (structure vacancy) of an Fe atom, and x is 0-0.223.

Sulfur-containing petroleum wastewater: the sulfur-containing petroleum wastewater produced by oil refining in petroleum refineries has the following main component contents as shown in table 1:

TABLE 1 content of major Components of Sulfur-containing Petroleum contaminated Water

Oil content mg/L	Sulfide mg/L	Volatile phenol mg/L	Cyanide mg/L	Ammonia nitrogen mg/L
					100-400	5000-15000	200-1000	2-20	2000-8000

The technical scheme of the invention is as follows:

lithium/sodium ion battery negative electrode material Fe_1-xThe preparation method of the S/C comprises the following steps:

(1) carrying out oxidation reaction on the sulfur-containing petroleum sewage and an oxidant to obtain pretreated sulfur-containing petroleum sewage;

(2) adding an iron salt aqueous solution and an additive into the pretreated sulfur-containing petroleum sewage obtained in the step (1) to enable the pH value to be 2-5, and uniformly mixing to obtain a mixed solution; then carrying out hydrothermal treatment at the temperature of 150 ℃ and 220 ℃ for 10-48h, and obtaining a precursor through separation, washing, drying and grinding;

(3) the precursor obtained in the step (2) is subjected to heat preservation at 400 ℃ for 1-3h under the protection of inert gas and calcination at 800 ℃ for 5-12h under the conditions of 300-_1-xS/C。

According to the invention, the sulfur-containing petroleum sewage in the step (1) comprises the following components: 100-400mg/L oil, 5000-15000mg/L sulfide, 200-1000mg/L volatile phenol, 2-20mg/L cyanide, 2000-8000mg/L ammonia nitrogen.

According to the invention, the oxidant in the step (1) is one of peroxyacetic acid, hydrogen peroxide or ammonium persulfate aqueous solution with the mass concentration of 10-20%; preferably, the oxidant in the step (1) is aqueous hydrogen peroxide with the mass concentration of 15% in percentage by mass; the volume ratio of the oxidant to the sulfur-containing petroleum sewage in the step (1) is 0.5-2: 10.

According to the invention, the addition of the oxidant in the step (1) can oxidize and decompose organic matters and other components in the oil wastewater containing sulfur and stone by the oxidant, which is beneficial to subsequent reaction and volatilization of some useless components, and has the effects of removing peculiar smell and the like.

According to the invention, the oxidation reaction temperature in the step (1) is preferably 40-60 ℃, and the oxidation reaction time is preferably 20-40 min.

According to the invention, preferably, the ferric salt aqueous solution in the step (2) is one of ferric chloride or ferric nitrate aqueous solution; preferably, the ferric salt aqueous solution in the step (2) is ferric chloride aqueous solution.

According to the invention, the mass concentration of the ferric salt aqueous solution in the step (2) is preferably 0.05-0.15mol L^-1。

According to the invention, the additive in the step (2) is preferably one of the aqueous solution of ethylene diammonium tetraacetic acid, citric acid or glycine with the mass concentration of 1-3%; preferably, the additive in the step (2) is an aqueous solution of ethylene diamine tetraacetic acid with the mass concentration of 2% and a low percentage; the volume ratio of the additive to the ferric salt aqueous solution in the step (2) is 1-3: 30. the additive acts to promote the complexation reaction.

According to the invention, the molar concentration of the ferric salt in the mixed solution in the step (2) is preferably 0.04-0.11mol L^-1。

Preferably, according to the invention, the pH in step (2) is 4.

According to the invention, the hydrothermal reaction temperature in the step (2) is 180 ℃, and the hydrothermal treatment time is 24 h.

According to the present invention, preferably, the inert gas in the step (3) is one of nitrogen, argon or helium.

Preferably, in the step (3), the precursor is subjected to heat preservation at 350 ℃ for 2h and calcination at 700 ℃ for 8h under the protection of nitrogen to obtain the negative electrode material Fe_1-xS/C。

According to the invention, the preferable lithium/sodium ion battery negative electrode material is Fe_1-xIn S/C, Fe_1-x75-85% of S, 15-25% of C and Fe serving as the negative electrode material of the lithium/sodium ion battery_1-xThe specific surface area of S/C is 120-²The pore size distribution is 50-300 nm.

The cathode material Fe prepared by the invention_1-xThe application of the S/C as the negative electrode material of the lithium/sodium ion battery comprises the following application methods:

(1) mixing the cathode material Fe_1-xFully grinding and uniformly mixing the S/C, the conductive agent and the binder, adding an N-methyl pyrrolidone solvent, and uniformly stirring to obtain a precoated refined slurry;

(2) and uniformly coating the pre-coated refined slurry on a copper foil, and drying to obtain the negative electrode plate of the lithium/sodium ion battery, wherein the obtained negative electrode plate of the lithium/sodium ion battery is used for a button type lithium/sodium ion battery.

The invention has the following beneficial effects:

1. the invention adopts industrial waste sulfur-containing petroleum sewage as a carbon source and a sulfur source to synthesize the porous composite material Fe_1-xS/C; the invention not only can remove the peculiar smell of the petroleum sewage, but also more importantly, iron and sulfur are easy to react to form stable Fe with good electrochemical performance by key process technologies such as sulfur-containing petroleum sewage pretreatment, additive addition, hydrothermal treatment, sectional calcination and the like_1-xThe S/C composite material has the advantages of simple preparation method, high synthesis efficiency and low synthesis cost, realizes effective reutilization of waste resources, reduces environmental pollution, and has good economic and social benefits.

2. The battery composite cathode material Fe prepared by the method of the invention_1-xThe S/C is a porous structure and has excellent electrochemical performance; as the negative electrode material of the sodium ion battery, the charge-discharge voltage is 0.01-3.0V and 0.5Ag^-1The first discharge specific capacity under the current density reaches 1542.1mAh g^-1And the discharge capacity after 50 times of circulation is 512.5mAh g^-1And the electrochemical performance is excellent.

Drawings

FIG. 1 shows Fe as an anode material synthesized in example 1 of the present invention_1-xXRD pattern of S/C with diffraction intensity on the ordinate and diffraction angle (2 theta) on the abscissa.

FIG. 2 shows Fe as an anode material synthesized in example 1 of the present invention_1-xAn energy spectrum of S/C; wherein (a) is a negative electrode material Fe_1-xScanning electron microscope image of S/C, and (b) is energy spectrum of C.

FIG. 3 shows Fe as the anode material synthesized in example 1 of the present invention_1-xAnd (3) an electrochemical cycle performance diagram of S/C.

Detailed Description

The present invention will be further described with reference to the following detailed description of embodiments thereof, but not limited thereto, in conjunction with the accompanying drawings.

The starting materials used in the examples are conventional and the processes described are known in the art unless otherwise specified.

In the examples, the sour oil is from an oil refinery, and the main components of the sour oil are shown in table 2:

TABLE 2 Main component content of Sulfur-containing Petroleum Sewage

Oil content mg/L	Sulfide mg/L	Volatile phenol mg/L	Cyanide mg/L	Ammonia nitrogen mg/L
					255.34	9875.46	615.09	15.36	5323.78

Example 1

taking 10mL of sulfur-containing petroleum sewage into a three-neck flask, adding 1.5mL of 15 wt% aqueous hydrogen peroxide, and stirring for 30min at 50 ℃ to obtain pretreated sulfur-containing petroleum sewage; then 30mL of 0.1mol L^-1Slowly dripping the ferric chloride aqueous solution into the pretreated sulfur-containing petroleum sewage, continuously stirring, adding 2ml of 2 wt% ethylene diammonium tetraacetic acid aqueous solution to enable the pH value to be 4, and stirring for 2 hours at normal temperature to obtain a uniform mixed solution; the mixed solution is put into a reaction kettleCarrying out hydrothermal treatment at 180 ℃ for 24h, naturally cooling to room temperature, carrying out centrifugal separation to obtain a precipitate, and drying at 60 ℃ to obtain black powder; washing the black powder twice with water, then washing the black powder once with ethanol, drying the black powder for 2 hours at 100 ℃, and then fully grinding the black powder to obtain a precursor; keeping the precursor at 350 ℃ for 2h and calcining at 700 ℃ for 8h under the protection of nitrogen atmosphere, and naturally cooling to room temperature to obtain Fe_1-xAnd (3) an S/C porous negative electrode material.

The negative electrode material Fe prepared in this example_1-xThe XRD pattern and energy spectrum of S/C are shown in FIGS. 1 and 2, and it can be seen from FIGS. 1 and 2(b) that the material prepared in this example is Fe_1-xA composite of S and C.

The negative electrode material Fe prepared in this example_1-xFig. 2(a) shows a scanning electron micrograph of S/C, and as can be seen from fig. 2(a), the material prepared in this example was a porous material. The specific surface area of the anode material prepared in this example was 169.8m²The pore size distribution of the particles is 50-300 nm.

Electrochemical performance test

The negative electrode material Fe prepared in the embodiment_1-xThe S/C is used as a sodium ion battery, and an electrode is prepared by adopting a coating method. The negative electrode material Fe of the sodium-ion battery prepared in the embodiment_1-xFully grinding and mixing S/C, acetylene black and polyvinylidene fluoride (PVDF) according to the mass ratio of 8:1:1, adding an N-methyl pyrrolidone solvent, and uniformly stirring to obtain a precoated refined slurry; and uniformly coating the pre-coated refined slurry on a copper foil, drying at 60 ℃ for 6h and vacuum drying at 120 ℃ for 12h, naturally cooling, and cutting into a wafer with the diameter of 15cm by using a sheet punching machine to obtain the negative electrode plate of the sodium-ion battery. Sequentially assembling the positive electrode shell, the electrode plate, the electrolyte, the diaphragm, the electrolyte, the lithium plate, the gasket and the negative electrode shell, and sealing the battery by using a sealing machine to obtain the CR2032 type button half-battery; the electrolyte used is LiPF₆Dissolving in mixed solvent of DMC and EC, and LiPF in electrolyte₆The concentration of (A) is 1mL/L, and the mass ratio of DMC to EC is 1: 1. and finally, performing constant-current charge and discharge test on the battery by an A713-2008S-3TGF-A type high-precision charge and discharge instrument.

The charge-discharge voltage of the negative electrode material prepared in this example is 001 to 3.00V and 0.5A g^-1The first discharge specific capacity under the current density is 1542.14mAh g^-1And the discharge capacity after 50 times of circulation is 512.5mAh g^-1The electrochemical cycling performance is shown in fig. 3. As can be seen from FIG. 3, the negative electrode material prepared by the invention has excellent electrochemical performance when applied to a sodium ion battery.

Example 2

taking 10mL of sulfur-containing petroleum sewage into a three-neck flask, adding 0.5mL of 15 wt% peracetic acid aqueous solution, and stirring at 40 ℃ for 40min to obtain pretreated sulfur-containing petroleum sewage; then 40mL of 0.1mol L^-1Slowly dripping an iron nitrate aqueous solution into the pretreated sulfur-containing petroleum sewage, continuously stirring, adding 2ml of 2 wt% citric acid aqueous solution to adjust the pH value to 2, and stirring at normal temperature for 2 hours to obtain a uniform mixed solution; putting the mixed solution into a reaction kettle, carrying out hydrothermal treatment at 150 ℃ for 48h, naturally cooling to room temperature, carrying out centrifugal separation to obtain a precipitate, and drying at 60 ℃ to obtain black powder; washing the black powder twice with water, then washing the black powder once with ethanol, drying the black powder for 2 hours at 100 ℃, and then fully grinding the black powder to obtain a precursor; the precursor is subjected to heat preservation at 400 ℃ for 1h and calcination at 600 ℃ for 12h under the protection of nitrogen atmosphere, and then is naturally cooled to room temperature, so that Fe can be obtained_1-xAnd (3) an S/C porous negative electrode material.

The negative electrode material Fe prepared in the embodiment_1-xS/C was used as a sodium ion battery, and a CR2032 type coin half cell was prepared and subjected to electrochemical performance test in the same manner as in example 1. The negative electrode material Fe prepared in this example_1-xThe charging and discharging voltage of S/C is 0.01-3.00V and 0.1A g^-1The specific capacity of the first discharge is 1250.7mAh g under the current density^-1And the specific discharge capacity after 50 times of charge-discharge circulation is 233.1mAh g^-1。

Example 3

10mL of sulfur-containing petroleum wastewater is taken and added into a three-neck flask with 2mLStirring the ammonium persulfate aqueous solution with the concentration of 15 wt% at 60 ℃ for 20min to obtain pretreated sulfur-containing petroleum sewage; then 25mL of 0.1mol L^-1Slowly dripping the ferric chloride aqueous solution into the pretreated sulfur-containing petroleum sewage, continuously stirring, adding 2ml of 2 wt% aminoacetic acid aqueous solution to enable the pH value to be 5, and stirring for 2 hours at normal temperature to obtain a uniform mixed solution; putting the mixed solution into a reaction kettle, carrying out hydrothermal treatment at 220 ℃ for 10h, naturally cooling to room temperature, carrying out centrifugal separation to obtain a precipitate, and drying at 60 ℃ to obtain black powder; washing the black powder twice with water, then washing the black powder once with ethanol, drying the black powder for 2 hours at 100 ℃, and then fully grinding the black powder to obtain a precursor; keeping the precursor at 300 ℃ for 3h and calcining at 800 ℃ for 5h under the protection of nitrogen atmosphere, and naturally cooling to room temperature to obtain Fe_1-xAnd (3) an S/C porous negative electrode material.

The negative electrode material Fe prepared in the embodiment_1-xS/C was used as a sodium ion battery, and a CR2032 type coin half cell was prepared and subjected to electrochemical performance test in the same manner as in example 1. The charging and discharging voltage is 0.01-3.00V and 0.1A g^-1The specific capacity of the first discharge is 965.4mAh g under the current density^-1And the specific discharge capacity after 50 times of charge-discharge circulation is 402.4mAhg^-1。

Comparative example 1

Fe_1-xThe preparation method of the S/C composite material is different from the embodiment 1 in that no oxidant and additive are added, and the specific steps are as follows:

10mL of sulfur-containing petroleum sewage is taken and put in a three-neck flask, and stirred for 30min at 50 ℃; then 30mL of 0.1mol L^-1Slowly dripping the ferric chloride aqueous solution into the sulfur-containing petroleum sewage, and stirring for 2 hours at normal temperature to obtain a uniform mixed solution; putting the mixed solution into a reaction kettle, carrying out hydrothermal treatment at 180 ℃ for 24h, naturally cooling to room temperature, carrying out centrifugal separation to obtain a precipitate, and drying at 60 ℃ to obtain black powder; washing the black powder twice with water, then washing the black powder once with ethanol, drying the black powder for 2 hours at 100 ℃, and then fully grinding the black powder to obtain a precursor; keeping the precursor at 350 ℃ for 2h and calcining at 700 ℃ for 8h under the protection of nitrogen atmosphere, and naturally cooling to room temperature to obtain Fe_1-xAn S/C composite material.

Fe obtained by the comparative example_1-xThe S/C composite material is used as a sodium ion battery, and a CR2032 type button half-cell is prepared according to the method of the embodiment 1 and is subjected to electrochemical performance test. Fe prepared in this comparative example_1-xThe charge-discharge voltage of the S/C composite material is 0.01-3.00V and 0.1A g^-1The specific capacity of the first discharge is 750.6mAh g under the current density^-1The specific discharge capacity after 50 times of charge-discharge circulation is 210.1mAh g^-1It can be seen that the addition of oxidants and additives has an important role in the preparation of the final product, the Fe prepared by the invention_1-xThe S/C composite material has more excellent electrochemical performance.

Comparative example 2

Fe_1-xThe preparation method of the S/C composite material is different from the embodiment 1 in that the hydrothermal reaction is replaced by a water bath reaction at 100 ℃ under normal pressure, and the preparation method comprises the following specific steps:

taking 10mL of sulfur-containing petroleum sewage into a three-neck flask, adding 1.5mL of 15 wt% aqueous hydrogen peroxide, and stirring for 30min at 50 ℃ to obtain pretreated sulfur-containing petroleum sewage; then 30mL of 0.1mol L^-1Slowly dripping the ferric chloride aqueous solution into the pretreated sulfur-containing petroleum sewage, continuously stirring, adding 2ml of 2 wt% ethylene diammonium tetraacetic acid aqueous solution to enable the pH value to be 4, and stirring for 2 hours at normal temperature to obtain a uniform mixed solution; carrying out water bath reaction treatment on the mixed solution at 100 ℃ for 24h, naturally cooling to room temperature, carrying out centrifugal separation to obtain a precipitate, and drying at 60 ℃ to obtain black powder; washing the black powder twice with water, then washing the black powder once with ethanol, drying the black powder for 2 hours at 100 ℃, and then fully grinding the black powder to obtain a precursor; keeping the precursor at 350 ℃ for 2h and calcining at 700 ℃ for 8h under the protection of nitrogen atmosphere, and naturally cooling to room temperature to obtain Fe_1-xAn S/C composite material.

Fe obtained by the comparative example_1-xThe S/C composite material is used as a sodium ion battery, and a CR2032 type button half-cell is prepared according to the method of the embodiment 1 and is subjected to electrochemical performance test. Fe prepared in this comparative example_1-xThe charge-discharge voltage of the S/C composite material is 0.01-3.00V and 0.1A g^-1First discharge specific capacity at current density830.4mAh g^-1And the specific discharge capacity after 50 times of charge-discharge circulation is 270.2mAh g^-1. Therefore, the hydrothermal reaction treatment plays an important role in the preparation of the final product, and the Fe prepared by the method is_1-xThe S/C composite material has more excellent electrochemical performance.

Comparative example 3

Fe_1-xThe preparation method of the S/C composite material is different from the embodiment 1 in that a one-step calcination method is adopted, and the preparation method comprises the following specific steps:

taking 10mL of sulfur-containing petroleum sewage into a three-neck flask, adding 1.5mL of 15 wt% aqueous hydrogen peroxide, and stirring for 30min at 50 ℃ to obtain pretreated sulfur-containing petroleum sewage; then 30mL of 0.1mol L^-1Slowly dripping the ferric chloride aqueous solution into the pretreated sulfur-containing petroleum sewage, continuously stirring, adding 2ml of 2 wt% ethylene diammonium tetraacetic acid aqueous solution to enable the pH value to be 4, and stirring for 2 hours at normal temperature to obtain a uniform mixed solution; putting the mixed solution into a reaction kettle, carrying out hydrothermal treatment at 180 ℃ for 24h, naturally cooling to room temperature, carrying out centrifugal separation to obtain a precipitate, and drying at 60 ℃ to obtain black powder; washing the black powder twice with water, then washing the black powder once with ethanol, drying the black powder for 2 hours at 100 ℃, and then fully grinding the black powder to obtain a precursor; calcining the precursor at 700 ℃ for 8h under the protection of nitrogen atmosphere, and naturally cooling to room temperature to obtain Fe_1-xAn S/C composite material.

Fe obtained by the comparative example_1-xThe S/C composite material is used as a sodium ion battery, and a CR2032 type button half-cell is prepared according to the method of the embodiment 1 and is subjected to electrochemical performance test. Fe prepared in this comparative example_1-xThe charge-discharge voltage of the S/C composite material is 0.01-3.00V and 0.1A g^-1The first discharge specific capacity is 921.8mAh g under the current density^-1And the specific discharge capacity after 50 times of charge-discharge circulation is 314.5mAh g^-1. It can be seen that the calcination process has an important role in the preparation of the final product, Fe prepared according to the invention_1-xThe S/C composite material has more excellent electrochemical performance.

Claims

1. Lithium/sodium ion battery cathodeMaterial Fe_1-xThe preparation method of the S/C comprises the following steps:

(1) carrying out oxidation reaction on the sulfur-containing petroleum sewage and an oxidant to obtain pretreated sulfur-containing petroleum sewage; the oxidant is one of peroxyacetic acid, hydrogen peroxide or aqueous solution of ammonium persulfate with the mass concentration of 10-20%; the volume ratio of the oxidant to the sulfur-containing petroleum sewage is 0.5-2: 10;

(2) adding an iron salt aqueous solution and an additive into the pretreated sulfur-containing petroleum sewage obtained in the step (1) to enable the pH value to be 2-5, and uniformly mixing to obtain a mixed solution; then carrying out hydrothermal treatment at the temperature of 150 ℃ and 220 ℃ for 10-48h, and obtaining a precursor through separation, washing, drying and grinding; the additive is one of ethylene diammonium tetraacetic acid, citric acid or aminoacetic acid water solution with the mass concentration of 1-3%; the volume ratio of the additive to the ferric salt aqueous solution is 1-3: 30, of a nitrogen-containing gas; the molar concentration of the ferric salt in the mixed solution is 0.04-0.11mol L^-1；

2. The negative electrode material Fe for lithium/sodium ion battery according to claim 1_1-xThe preparation method of S/C is characterized in that the oxidizing agent in the step (1) is aqueous hydrogen peroxide with the mass concentration of 15% h.

3. The negative electrode material Fe for lithium/sodium ion battery according to claim 1_1-xThe preparation method of S/C is characterized in that the oxidation reaction temperature in the step (1) is 40-60 ℃, and the oxidation reaction time is 20-40 min.

4. The negative electrode material Fe for lithium/sodium ion battery according to claim 1_1-xThe preparation method of S/C is characterized in that the ferric salt aqueous solution in the step (2) is one of ferric chloride aqueous solution or ferric nitrate aqueous solution; the molarity of the ferric salt water solution in the step (2) is 0.05-0.15mol L^-1。

5. The negative electrode material Fe for lithium/sodium ion battery according to claim 1_1-xThe preparation method of S/C is characterized in that the additive in the step (2) is an aqueous solution of ethylene diamine tetraacetic acid with mass concentration of 2%.

6. The negative electrode material Fe for lithium/sodium ion battery according to claim 1_1-xThe preparation method of S/C is characterized in that the pH value in the step (2) is 4.

7. The negative electrode material Fe for lithium/sodium ion battery according to claim 1_1-xThe preparation method of S/C is characterized in that the hydrothermal reaction temperature in the step (2) is 180 ℃, and the hydrothermal treatment time is 24 h.

8. The negative electrode material Fe for lithium/sodium ion battery according to claim 1_1-xThe preparation method of S/C is characterized in that in the step (3), the precursor is subjected to heat preservation at 350 ℃ for 2h and calcination at 700 ℃ for 8h under the protection of nitrogen to obtain the cathode material Fe_1-xS/C。

9. The negative electrode material Fe for lithium/sodium ion battery according to claim 1_1-xThe preparation method of S/C is characterized in that the lithium/sodium ion battery negative electrode material Fe_1-xIn S/C, Fe_1-x75-85% of S, 15-25% of C and Fe serving as the negative electrode material of the lithium/sodium ion battery_1-xThe specific surface area of S/C is 120-²The pore size distribution is 50-300 nm.