CN114628623B - KFESO (KFEESO) with carbon nano tube interpenetration 4 Preparation method and application of F material - Google Patents

KFESO (KFEESO) with carbon nano tube interpenetration 4 Preparation method and application of F material Download PDF

Info

Publication number
CN114628623B
CN114628623B CN202210141854.6A CN202210141854A CN114628623B CN 114628623 B CN114628623 B CN 114628623B CN 202210141854 A CN202210141854 A CN 202210141854A CN 114628623 B CN114628623 B CN 114628623B
Authority
CN
China
Prior art keywords
nano tube
carbon nano
kfsf
preparation
cnts
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN202210141854.6A
Other languages
Chinese (zh)
Other versions
CN114628623A (en
Inventor
周小四
廖家英
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nanjing Normal University
Original Assignee
Nanjing Normal University
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nanjing Normal University filed Critical Nanjing Normal University
Priority to CN202210141854.6A priority Critical patent/CN114628623B/en
Publication of CN114628623A publication Critical patent/CN114628623A/en
Application granted granted Critical
Publication of CN114628623B publication Critical patent/CN114628623B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/04—Processes of manufacture in general
    • H01M4/0471—Processes of manufacture in general involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/054—Accumulators with insertion or intercalation of metals other than lithium, e.g. with magnesium or aluminium
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/04—Processes of manufacture in general
    • H01M4/049—Manufacturing of an active layer by chemical means
    • H01M4/0497—Chemical precipitation
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—Composites
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/5825—Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H01M4/587—Carbonaceous material, e.g. graphite-intercalation compounds or CFx for inserting or intercalating light metals
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/624—Electric conductive fillers
    • H01M4/625—Carbon or graphite
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/028—Positive electrodes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Abstract

The invention discloses a KFESO (KFEESO) with carbon nano tube interpenetration 4 The preparation method and application of the F material are as follows: acidifying the carbon nano tube and dispersing the acidified carbon nano tube in a polyalcohol solvent to obtain a carbon nano tube dispersion liquid; stirring and dissolving an iron source and potassium fluoride in the carbon nano tube dispersion liquid to obtain a mixed liquid; carrying out solvothermal reaction on the mixed solution to generate precipitate; calcining the precipitate in a reducing atmosphere. The method disclosed by the invention is simple in process, the used raw materials are environment-friendly, and the prepared KFSF@CNTs material has excellent electrochemical performance, so that the KFSF@CNTs material is a promising positive electrode material of a potassium ion battery.

Description

KFESO (KFEESO) with carbon nano tube interpenetration 4 Preparation method and application of F material
Technical Field
The invention relates to a preparation method and application of a positive electrode material of a potassium ion battery, in particular to KFESO (potassium ion exchange membrane) with carbon nano tubes inserted 4 F, preparing and applying the material.
Background
Lithium ion batteries have become a main power source in the fields of electric automobiles, portable electronic devices, and even stationary energy storage systems due to the advantages of high energy density, long cycle life, high operating voltage, and the like. However, the scarcity and high price of lithium resources is detrimental to its use in large-scale energy storage systems. In recent years, potassium ion batteries have attracted a great deal of interest as a promising alternative. Potassium and sodium are more abundant in nature and less expensive than lithium, and they are similar to the electrochemical mechanism of lithium ion batteries. In addition, oxidation-reduction potential of potassium (K/K) + : -2.93V) to sodium (Na/Na + : -2.71V) is lower, the solvated potassium ion radius is smaller, so that the potassium ion battery can have higher energy density, higher rate capability and greater potential in practical application.
KFeSO 4 F is an ideal positive electrode material of the potassium ion battery because the raw materials are low in cost and easy to obtain, and meanwhile, the F has three-dimensional ion channel, high theoretical specific capacity, high working voltage and high structural stability. KFESO, however 4 F belongs to polyanion compounds, and has poor electronic conductivity. However, KFESO is poor in thermal stability (decomposition at temperatures exceeding 450 ℃ C.) 4 F after synthesis ofIn the process, high-temperature calcination is difficult, and carbon coating cannot be performed by such a method. Thus KFESO 4 The development and application of the F material are limited by lower practical specific capacity and poorer cycle stability and multiplying power capability.
Traditional KFESO 4 F material is synthesized by mixing FeSO 4 Mixing with KF ball mill, and calcining at about 380 deg.C for 4 days. The reaction is time consuming and some impurity phases are often present in the product. In recent years, researchers have begun to attempt to synthesize kfeseo using solvothermal methods 4 F, by FeSO 4 ·7H 2 O and KF are obtained by solvothermal reaction in ethylene glycol solvent, and the reaction time is only 6 hours. KFESO is then processed by solid phase ball milling 4 F is mechanically mixed with graphene with high conductivity, and the obtained composite material has higher specific capacity compared with the initial material, but has limited improvement of cycle and rate performance.
Thus, in the conventional solid phase method, feSO 4 The reaction with KF takes a long time and the reaction product also has some electrochemically inactive impurity phases. Second, the mechanical mixing carbon-coated method can destroy KFESO 4 F original microstructure, and the tightness of the contact between the material and the carbon material still needs to be improved.
Disclosure of Invention
The invention aims to: the first object of the present invention is to provide KFESO with excellent cycle performance and rate performance of carbon nanotube interpenetration 4 F, preparing a material;
the second object of the present invention is to provide a KFESO with the carbon nanotubes inserted therein 4 KFESO (KFEESO) interpenetrated by carbon nano tube prepared by preparation method of F material 4 Application of F material.
The technical scheme is as follows: KFESO with carbon nanotubes inserted in the invention 4 The preparation method of the F material comprises the following steps:
(1) Acidifying the carbon nano tube and dispersing the acidified carbon nano tube in a polyalcohol solvent to obtain a carbon nano tube dispersion liquid;
(2) Stirring and dissolving an iron source and potassium fluoride in the carbon nano tube dispersion liquid to obtain a mixed liquid;
(3) Carrying out solvothermal reaction on the mixed solution in the step (2) to generate a precipitate;
(4) Calcining the precipitate in the step (3) in a reducing atmosphere to obtain KFESO (KFES O) with carbon nanotubes inserted therein 4 And F, material.
Wherein the polyol in the step (1) is one of ethylene glycol, diethylene glycol, triethylene glycol or glycerol; hereinafter, ethylene glycol, diethylene glycol, triethylene glycol, and glycerin are abbreviated as EG, DEG, TEG, gly, respectively.
In the step (2), the mass ratio of the iron source, the potassium fluoride and the carbon nano tube is 1:0.21 to 0.23:0.036 to 0.072.
Wherein the concentration of the carbon nanotube dispersion liquid in the step (1) is 1.0-2.0 g L -1 。
In the step (1), the carbon nanotubes are acidified by adopting a mixed solution of concentrated sulfuric acid/concentrated nitric acid, wherein the volume ratio of the concentrated sulfuric acid to the concentrated nitric acid is preferably 3:1.
Wherein the concentration of the iron source and the potassium fluoride in the step (2) is 0.1 to 0.2mol L -1 The method comprises the steps of carrying out a first treatment on the surface of the The iron source is FeSO 4 ·7H 2 O。
Wherein the reaction temperature in the step (3) is 150-180 ℃ and the reaction time is 2-6 h.
Wherein the solvothermal reaction in the step (3) is carried out under stirring; the stirring mode is magnetic stirring, and the speed is controlled to be 1000-2000 rpm.
Wherein, the diameter of the carbon nano tube in the step (1) is 10-50 nm, and the length is 10-30 mu m.
Wherein the reducing atmosphere in the step (4) is hydrogen-argon mixed gas, and the volume percentage of hydrogen in the hydrogen-argon mixed gas is 5-10%.
Wherein the calcining method in the step (4) comprises the following steps: drying the precipitate obtained in the step (3), and then placing the dried precipitate in a tube furnace for 3-5 ℃ for min -1 After the temperature is raised to 350-380 ℃, the temperature is kept for 2-6 h.
KFESO with the carbon nanotubes inserted therein 4 KFESO (KFEESO) with carbon nano tube interpenetration is prepared by a preparation method of F material 4 F material as potassium ion electricityApplication of cell positive electrode material.
The invention adopts low-cost polyol as solvent in the synthesis process to lead FeSO 4 ·7H 2 O and KF dissolve and form KFESO in solvothermal process 4 F precipitation grows on the carbon nano tube in situ, the reaction time is short, and the purity of the obtained product is high. The morphology of the product is controllably changed through the regulation and control of different solvents. In addition, the method uses carbon nano tube as nucleation additive, and can induce KFESO 4 F, uniformly nucleating and growing to form a unique shape, and the method is simple in process and environment-friendly in raw materials.
The method can prepare the KFSF@CNTs material interspersed with the micron-sized carbon nanotubes, is favorable for electrons to be transmitted among particles along the carbon nanotubes, greatly promotes the exertion of material capacity, and improves the cycle stability and the multiplying power performance of the KFSF@CNTs material. The micron-sized particles also facilitate the stacking of materials, achieving higher tap densities, corresponding to higher volumetric energy densities. In addition, KFESO obtained by the method 4 F is KTiOPO 4 The structure has three-dimensional ion channels, can accelerate ion conduction and reduce the energy barrier of the potassium ion battery in the charge and discharge process.
The beneficial effects are that: compared with the prior art, the invention has the following remarkable effects: the KFSF@CNTs material prepared by the method has excellent electrochemical performance, and is used as a positive electrode material of a potassium ion battery, wherein KFSF@CNTs is at 0.2C multiplying power (1 C=128 mA g) -1 ) When 110.9mAh g was provided -1 Reversible capacity, average operating voltage reaches 3.73V. Can still provide 69.6mAh g under 20C high magnification -1 Reversible capacity, shows good cycle stability at 1000 cycles at 1C rate, and capacity retention is 88.9%. In addition, the KFSF@CNTs// graphite potassium ion full cell shows a reversible capacity of 110.1mAh g at 0.2C rate -1 The energy density reaches 370Wh kg -1 The capacity retention after 300 cycles was 81.1%. Therefore, the carbon nanotube interpenetrated material has good application potential as a high-performance low-cost anode material.
Drawings
FIG. 1 is a schematic view of XRD refinement and crystal structure of KFSF@CNTs/DEG material of example 1 of the present invention;
FIG. 2 is an XPS survey spectrum of KFSF@CNTs/DEG material of example 1 of the present invention;
FIG. 3 is a Mossburger spectrum of KFSF@CNTs/DEG material according to example 1 of the present invention;
FIG. 4 is an SEM image of KFSF@CNTs/DEG material according to example 1 of the present invention;
FIG. 5 is a TEM image and HRTEM image of KFSF@CNTs/DEG material of example 1 of the present invention;
FIG. 6 is a cyclic voltammogram of KFSF@CNTs/DEG electrode of example 1 of the present invention;
FIG. 7 is a graph of the charge/discharge curve and dQ/dV for KFSF@CNTs/DEG electrode of example 1 of the present invention;
FIG. 8 is a graph of the rate performance and charge-discharge curves of the KFSF@CNTs/DEG of example 1 and the materials of comparative examples 1 and 2 of the present invention at different current densities;
FIG. 9 is a graph of charge and discharge curves and cycle performance at 0.2C rate for KFSF@CNTs/DEG for example 1 and comparative examples 1, 2 according to the present invention;
FIG. 10 is a graph of the cycle performance of KFSF@CNTs/DEG at 1C magnification for example 1 of the present invention;
FIG. 11 is an SEM image of KFSF@CNTs/EG material according to example 4 of the present invention;
FIG. 12 is an SEM image of KFSF@CNTs/TEG material according to example 5 of the invention;
FIG. 13 is an SEM image of KFSF@CNTs/Gly material according to example 6 of the present invention;
FIG. 14 is an SEM image of KFSF/DEG of comparative example 1 of the present invention;
FIG. 15 is an XRD spectrum of comparative example 3 of the present invention;
fig. 16 is an XRD spectrum of comparative example 4 of the present invention.
Detailed Description
The present invention is described in further detail below.
Example 1
Preparation of KFSF@CNTs material:
(1) 1g of carbon nano tube with the diameter of 10-30 nm and the length of 20-30 mu m is added into a mixed solvent of 20mL of concentrated nitric acid and 60mL of concentrated sulfuric acid, heated and stirred for 8h at the temperature of 70 ℃. Cooling, diluting with 400mL of deionized water, and separating by suction filtration;
(2) 50mg of acidified carbon nanotubes are added into 50mL of diethylene glycol solvent, and the mixture is subjected to ultrasonic treatment for 1h to obtain a concentration of 1g L -1 Is a uniform carbon nanotube dispersion of (a);
(3) 1.39g FeSO 4 ·7H 2 Adding O and 0.29g KF into the carbon nanotube dispersion, stirring for 0.5h to dissolve thoroughly, wherein the concentration of both is 0.1mol L -1 ；
(4) The dispersion obtained in step (3) was added to a 100mL hydrothermal kettle, placed in an oil bath, heated to 160℃and kept at constant temperature for 6 hours while maintaining a magnetic stirring speed of 1500rpm. After cooling to room temperature, the obtained precipitate is separated by centrifugation, washed 3 times with acetone, and finally dried in vacuum at 80 ℃;
(5) Placing the precipitate obtained in the step (4) in a hydrogen-argon mixed gas tube furnace containing 5vol% of hydrogen at 3 ℃ for min -1 And (3) heating to 350 ℃ for calcining for 2 hours, and cooling to obtain the product. Since the reaction solvent diethylene glycol was DEG, the sample was labeled KFSF@CNTs/DEG.
Characterization of KFSF@CNTs/DEG materials:
FIG. 1 is a schematic representation of XRD structure refinement and corresponding crystal structure of a KFSF@CNTs/DEG material showing that the material is a pure phase compound having a KTP structure; FIG. 2 is an XPS survey spectrum of KFSF@CNTs/DEG showing the presence of K, fe, S, O, F and C elements; FIG. 3 is a Mossburger spectrum of KFSF@CNTs/DEG, which demonstrates that the valence state of Fe is +2.
And analyzing the size, morphology and microstructure of the obtained KFSF@CNTs/DEG material by using SEM, TEM and HRTEM. FIGS. 4a and 4b are SEM images of KFSF@CNTs/DEG material, and FIG. 4a shows that the secondary particles of KFSF@CNTs/DEG are of uniform football-shaped structure and have a particle size of about 2 μm; FIG. 4b shows KFSF@CNTs/DEG stacked by diamond-shaped primary particles of about 200nm, interspersed with carbon nanotubes. FIGS. 5a and 5b are TEM diagrams of KFSF@CNTs/DEG, which also show carbon nanotubes interspersed in primary particles of KFSF; FIG. 5c is a HRTEM image of KFSF@CNTs/DEG showing that the lattice spacing of the (201) and (011) crystal planes in KFSF@CNTs/DEG is 0.562nm and the angle between the two crystal planes is 74.5 DEG.
Electrochemical performance test:
the KFSF@CNTs/DEG prepared in the embodiment is ground and mixed uniformly with carbon black and polyvinylidene fluoride in a mass ratio of 70:20:10 by taking 1-methyl-2-pyrrolidone as a solvent, and the obtained uniform slurry is smeared on an Al foil and dried in vacuum for 12 hours at 80 ℃. Using 1mol L -1 KPF 6 Ethylene Carbonate (EC) and Propylene Carbonate (PC) (volume ratio is 1:1) are used as electrolyte of potassium ion battery, and glass fiber and metallic potassium are respectively used as diaphragm and counter electrode of potassium ion battery. Electrochemical performance was tested using a CR2032 cell. The battery assembly was performed in a glove box filled with an argon atmosphere, with both water and oxygen concentrations of less than 0.1ppm. Constant current charge and discharge test of the battery at room temperature using a blue CT2001A multichannel battery test system at 2.0-4.5V (vs. K + K) in a fixed voltage range. The specific properties are shown in fig. 6 to 10.
FIG. 6 is a graph of KFSF@CNTs/DEG electrode at 2.0-4.5V (vs. K + K) voltage interval, scan rate of 0.1mV s -1 The cyclic voltammograms of the first three circles are basically coincident, which shows that the material has good reversibility of potassium removal; FIG. 7 is a graph of KFSF@CNTs/DEG at 2.0-4.5V (vs.K + Charge/discharge curve diagram of/K) voltage interval, current density of 0.2C, reversible specific capacity of 110.9mAh g -1 The average operating voltage is 3.73V, where 1c=128 mA g -1 Wherein the dQ/dV curve shows four pairs of redox peaks corresponding to four voltage platforms of the charge-discharge curve; FIG. 8a is a graph showing the rate performance of KFSF@CNTs/DEG with KFSF/DEG without carbon nanotube interpenetration in comparative example 1 and KFSF/DEG+5wt% CNTs of mechanically ball-milled mixed carbon nanotubes in comparative example 2 at different current densities, wherein it can be seen that the KFSF@CNTs/DEG has a capacity of 69.6mAh g even at a high current density of 20C -1 FIG. 8b is a graph showing the charge and discharge curves of KFSF@CNTs/DEG at different current densities; FIGS. 9a and 9b are graphs of charge and discharge curves and cycle performance at 0.2C current density for KFSF@CNTs/DEG and comparative example 1, respectively, showing that the KFSF@CNTs/DEG is higher in capacity; FIG. 10 is KFSF@CNTsCycling performance plot of/DEG at 1C current density, showing that after 1000 cycles of KFSF@CNTs/DEG, the capacity retention rate reached 88.9%.
Example 2
(1) 1g of carbon nano tube with the diameter of 10-30 nm and the length of 20-30 mu m is added into a mixed solvent of 20mL of concentrated nitric acid and 60mL of concentrated sulfuric acid, heated and stirred for 8h at the temperature of 70 ℃. Cooling, diluting with 400mL of deionized water, and separating by suction filtration;
(2) Adding 100mg of acidified carbon nano tube into 50mL of diethylene glycol solvent, and performing ultrasonic treatment for 1h to obtain a concentration of 2g L -1 Is a uniform carbon nanotube dispersion of (a).
(3) 2.78g FeSO 4 ·7H 2 Adding O and 0.58g KF into the carbon nanotube dispersion, stirring for 0.5h to dissolve thoroughly, wherein the concentration of both is 0.2mol L -1 ；
(4) The dispersion obtained in step (3) was added to a 100mL hydrothermal kettle, placed in an oil bath, heated to 160℃and kept at constant temperature for 6 hours while maintaining a magnetic stirring speed of 1500rpm. After cooling to room temperature, the obtained precipitate is separated by centrifugation, washed 3 times with acetone, and finally dried in vacuum at 80 ℃;
(5) Placing the precipitate obtained in the step (4) in a hydrogen-argon mixed gas tube furnace containing 5vol% of hydrogen at 3 ℃ for min -1 And (3) heating to 350 ℃ for calcining for 2 hours, and cooling to obtain the product.
The prepared KFSF@CNTs material was subjected to structural characterization and electrochemical performance test in the same manner as in example 1, and the results of the structural characterization are basically the same as in example 1, and the results of the electrochemical performance test are shown in Table 1.
Example 3
(1) 1g of carbon nano tube with the diameter of 10-30 nm and the length of 20-30 mu m is added into a mixed solvent of 20mL of concentrated nitric acid and 60mL of concentrated sulfuric acid, heated and stirred for 8h at the temperature of 70 ℃. Cooling, diluting with 400mL of deionized water, and separating by suction filtration;
(2) Adding 100mg of acidified carbon nano tube into 50mL of diethylene glycol solvent, and performing ultrasonic treatment for 1h to obtain a concentration of 2g L -1 Is a uniform carbon nanotube dispersion of (a).
(3) 1.39g FeSO 4 ·7H 2 Adding O and 0.32g KF into the carbon nanotube dispersion, stirring for 0.5h to dissolve thoroughly, wherein the concentrations of the O and KF are 0.1mol L and 0.11mol L respectively -1 ；
(4) The dispersion obtained in step (3) was added to a 100mL hydrothermal kettle, placed in an oil bath, heated to 160℃and kept at constant temperature for 6 hours while maintaining a magnetic stirring speed of 1500rpm. After cooling to room temperature, the obtained precipitate is separated by centrifugation, washed 3 times with acetone, and finally dried in vacuum at 80 ℃;
(5) Placing the precipitate obtained in the step (4) in a hydrogen-argon mixed gas tube furnace containing 5vol% of hydrogen at 3 ℃ for min -1 And (3) heating to 350 ℃ for calcining for 2 hours, and cooling to obtain the product.
The prepared KFSF@CNTs material was subjected to structural characterization and electrochemical performance test in the same manner as in example 1, and the results of the structural characterization are basically the same as in example 1, and the results of the electrochemical performance test are shown in Table 1.
Example 4
(1) 1g of carbon nano tube with the diameter of 10-30 nm and the length of 20-30 mu m is added into a mixed solvent of 20mL of concentrated nitric acid and 60mL of concentrated sulfuric acid, heated and stirred for 8h at the temperature of 70 ℃. Cooling, diluting with 400mL of deionized water, and separating by suction filtration;
(2) Adding 50mg of acidified carbon nano tube into 50mL of glycol solvent, and performing ultrasonic treatment for 1h to obtain a concentration of 1g L -1 Is a uniform carbon nanotube dispersion of (a).
(3) 1.39g FeSO 4 ·7H 2 Adding O and 0.29g KF into the carbon nanotube dispersion, stirring for 0.5h to dissolve thoroughly, wherein the concentration of both is 0.1mol L -1 ；
(4) The dispersion obtained in step (3) was added to a 100mL hydrothermal kettle, placed in an oil bath, heated to 160℃and kept at constant temperature for 6 hours while maintaining a magnetic stirring speed of 1500rpm. After cooling to room temperature, the obtained precipitate is separated by centrifugation, washed 3 times with acetone, and finally dried in vacuum at 80 ℃;
(5) Placing the precipitate obtained in the step (4) in a hydrogen-argon mixed gas tube furnace containing 5vol% of hydrogen at 3 ℃ for min -1 And (3) heating to 350 ℃ for calcining for 2 hours, and cooling to obtain the product. Because the reaction solvent is EG,the sample was labeled KFSF@CNTs/EG.
The resulting KFSF@CNTs/EG material was subjected to structural characterization and electrochemical performance testing in the same manner as in example 1. The morphology is shown in FIG. 11, the secondary particles of KFSF@CNTs/EG are also uniform football-shaped structures, the particle size is about 2 μm, but the primary particles are irregular particles, and a small amount of carbon nanotubes are attached to the surface. The results of the electrochemical performance test are shown in Table 1.
Example 5
(1) 1g of carbon nano tube with the diameter of 10-30 nm and the length of 20-30 mu m is added into a mixed solvent of 20mL of concentrated nitric acid and 60mL of concentrated sulfuric acid, heated and stirred for 8h at the temperature of 70 ℃. Cooling, diluting with 400mL of deionized water, and separating by suction filtration;
(2) Adding 50mg of acidified carbon nano tube into 50mL of triethylene glycol solvent, and performing ultrasonic treatment for 1h to obtain the concentration of 1g L -1 Is a uniform carbon nanotube dispersion of (a).
(3) 1.39g FeSO 4 ·7H 2 Adding O and 0.29g KF into the carbon nanotube dispersion, stirring for 0.5h to dissolve thoroughly, wherein the concentration of both is 0.1mol L -1 ；
(4) The dispersion obtained in step (3) was added to a 100mL hydrothermal kettle, placed in an oil bath, heated to 160℃and kept at constant temperature for 6 hours while maintaining a magnetic stirring speed of 1500rpm. After cooling to room temperature, the obtained precipitate is separated by centrifugation, washed 3 times with acetone, and finally dried in vacuum at 80 ℃;
(5) Placing the precipitate obtained in the step (4) in a hydrogen-argon mixed gas tube furnace containing 5vol% of hydrogen at 3 ℃ for min -1 And (3) heating to 350 ℃ for calcining for 2 hours, and cooling to obtain the product. Since the reaction solvent was TEG, the sample was labeled KFSF@CNTs/TEG.
The resulting KFSF@CNTs/TEG material was subjected to structural characterization and electrochemical performance testing in the same manner as in example 1. The morphology is shown in figure 12, KFSF@CNTs/TEG is a micron-sized diamond particle, and carbon nanotubes are inserted into the particle. The results of the electrochemical performance test are shown in Table 1.
Example 6
(1) 1g of carbon nano tube with the diameter of 10-30 nm and the length of 20-30 mu m is added into a mixed solvent of 20mL of concentrated nitric acid and 60mL of concentrated sulfuric acid, heated and stirred for 8h at the temperature of 70 ℃. Cooling, diluting with 400mL of deionized water, and separating by suction filtration;
(2) Adding 50mg of acidified carbon nano tube into 50mL of glycerin solvent, and performing ultrasonic treatment for 1h to obtain a concentration of 1g L -1 Is a uniform carbon nanotube dispersion of (a).
(3) 1.39g FeSO 4 ·7H 2 Adding O and 0.29g KF into the carbon nanotube dispersion, stirring for 0.5h to dissolve thoroughly, wherein the concentration of both is 0.1mol L -1 ；
(4) The dispersion obtained in step (3) was added to a 100mL hydrothermal kettle, placed in an oil bath, heated to 160℃and kept at constant temperature for 6 hours while maintaining a magnetic stirring speed of 1500rpm. After cooling to room temperature, the obtained precipitate is separated by centrifugation, washed 3 times with acetone, and finally dried in vacuum at 80 ℃;
(5) Placing the precipitate obtained in the step (4) in a hydrogen-argon mixed gas tube furnace containing 5vol% of hydrogen at 3 ℃ for min -1 And (3) heating to 350 ℃ for calcining for 2 hours, and cooling to obtain the product. Since the reaction solvent was Gly, the sample was labeled KFSF@CNTs/Gly.
The prepared KFSF@CNTs/Gly material was subjected to structural characterization and electrochemical performance test in the same manner as in example 1. The morphology is shown in figure 13, the secondary particles of KFSF@CNTs/Gly are of a rugby structure with larger length-diameter ratio, the length is about 4 mu m, the diameter is about 1 mu m, the primary particles are bar-shaped particles, and a small amount of carbon nanotubes are attached to the surface. The results of the electrochemical performance test are shown in Table 1.
The electrochemical properties of comparative examples 1,4,5, and 6 show that the KFSF sample prepared in diethylene glycol in example 1 has superior properties. Although the mass ratio of the initial iron source, the potassium fluoride and the carbon nano tube is the same, the mass ratio is 1:0.21:0.036. however, the carbon nanotube content of the samples of examples 1,4,5 and 6 was 4.6%,1.5%,2.1% and 2.5%, respectively, by the carbon content test. This indicates that KFSF is more likely to attach to carbon nanotubes in diethylene glycol solvent, allowing more carbon nanotubes to precipitate. The closer contact of KFSF with carbon nanotubes also makes the final electrochemical performance of the sample better. From the graph4. 11 are also known to be football-shaped, but kfeseo 4 F nucleates and grows faster in ethylene glycol and is less likely to grow along the carbon nanotubes, so that the carbon nanotube content in the sample of example 4 is less than that in the sample of example 1. From this, the higher the carbon nanotube content in the final sample, the more tightly the KFSF is bound to the carbon nanotubes, which is more advantageous for obtaining more excellent electrochemical properties. Compared with the diamond shape of the sample of the example 5 and the rod shape of the sample of the example 6, the rugby shape of the samples of the examples 1-4 is easier to closely stack materials and is more beneficial to improving the volume energy density.
Comparative example 1
Preparation of KFSF/DEG without carbon nanotube interpenetration:
(1) 1.39g FeSO 4 ·7H 2 O and 0.29g KF are added into 50mL of diethylene glycol, stirred for 0.5h to be fully dissolved, and the concentration of the O and the KF is 0.1mol L -1 ；
(2) The dispersion obtained in step (1) was added to a 100mL hydrothermal kettle, placed in an oil bath, heated to 160℃and kept at constant temperature for 6 hours while maintaining a magnetic stirring speed of 1500rpm. After cooling to room temperature, the obtained precipitate is separated by centrifugation, washed 3 times with acetone, and finally dried in vacuum at 80 ℃;
(3) Placing the precipitate obtained in the step (2) in a hydrogen-argon mixed gas tube furnace containing 5vol% of hydrogen at 3 ℃ for min -1 And (3) heating to 350 ℃ for calcining for 2 hours, and cooling to obtain the product. Since the reaction solvent was DEG and no carbon nanotubes, the sample was labeled as KFSF/DEG.
The resulting KFSF/DEG material was subjected to structural characterization and electrochemical performance testing in the same manner as in example 1. The morphology of the carbon nano tube is shown in fig. 14, KFSF/DEG is a micron-sized diamond particle, and compared with the morphology of KFSF@CNT/DEG, the carbon nano tube can be used as a nucleating agent, so that KFSF grows into smaller grains along the nucleation of the carbon nano tube. FIG. 9a is a graph of the rate performance of KFSF/DEG and KFSF@CNT/DEG at different current densities, the reversible capacity of KFSF@CNT/DEG being higher than KFSF/DEG; FIG. 8b is a graph comparing the cycle performance of KFSF@CNTs/DEG and KFSF/DEG at a current density of 0.2C, showing that the cycle stability of KFSF/DEG is far behind KFSF@CNTs/DEG; from the above test, the electrochemical performance of KFSF/DEG is far inferior to KFSF@CNTs/DEG.
Comparative example 2
Preparation of a carbon nanotube mechanically mixed KFSF sample:
(1) 1.39g FeSO 4 ·7H 2 O and 0.29g KF are added into 50mL of diethylene glycol, stirred for 0.5h to be fully dissolved, and the concentration of the O and the KF is 0.1mol L -1 ；
(2) The dispersion obtained in step (1) was added to a 100mL hydrothermal kettle, placed in an oil bath, heated to 160℃and kept at constant temperature for 6 hours while maintaining a magnetic stirring speed of 1500rpm. After cooling to room temperature, the obtained precipitate is separated by centrifugation, washed 3 times with acetone, and finally dried in vacuum at 80 ℃;
(3) Placing the precipitate obtained in the step (2) in a hydrogen-argon mixed gas tube furnace containing 5vol% of hydrogen at 3 ℃ for min -1 Is heated to 350 ℃ for calcination for 2 hours, and is then cooled to room temperature;
(4) The product from step (3) was ball-milled with 5wt% carbon nanotubes in a planetary ball mill at 500rpm for 12 hours, and the resulting sample was labeled KFSF/deg+5wt% cnts.
The electrochemical performance of the prepared KFSF/DEG +5wt% CNTs material was tested in the same manner as in example 1, and the results are shown in Table 1, and as shown in FIGS. 8 and 9, the electrochemical performance was significantly inferior to that of KFSF@CNTs/DEG samples interspersed with carbon nanotubes although the electrochemical performance was improved compared with those of KFSF/DEG samples without carbon nanotubes.
Comparative example 3
Preparation of KFSF samples using monohydric alcohol:
(1) 1g of carbon nano tube with the diameter of 10-30 nm and the length of 20-30 mu m is added into a mixed solvent of 20mL of concentrated nitric acid and 60mL of concentrated sulfuric acid, heated and stirred for 8h at the temperature of 70 ℃. Cooling, diluting with 400mL of deionized water, and separating by suction filtration;
(2) Adding 50mg of acidified carbon nano tube into 50mL of ethylene glycol monomethyl ether solvent, and performing ultrasonic treatment for 1h to obtain a concentration of 1g L -1 Is a uniform carbon nanotube dispersion of (a).
(3) 1.39g FeSO 4 ·7H 2 O and 0.29g KF were added to the carbon nanotube dispersion,stirring for 0.5h to dissolve completely, wherein the concentration of the two is 0.1mol L -1 ；
(4) The dispersion obtained in step (3) was added to a 100mL hydrothermal kettle, placed in an oil bath, heated to 160℃and kept at constant temperature for 6 hours while maintaining a magnetic stirring speed of 1500rpm. After cooling to room temperature, the obtained precipitate is separated by centrifugation, washed 3 times with acetone, and finally dried in vacuum at 80 ℃;
(5) Placing the precipitate obtained in the step (4) in a hydrogen-argon mixed gas tube furnace containing 5vol% of hydrogen at 3 ℃ for min -1 And (3) heating to 350 ℃ for calcining for 2 hours, and cooling to obtain the product.
The resulting material was subjected to structural characterization and electrochemical performance testing in the same manner as in example 1. The XRD structure characterization is shown in FIG. 15, and it can be found that K is obviously present in the product 2 SO 4 Mainly due to the low solubility of the potassium salt in monohydric alcohols. The results of the electrochemical performance test are shown in Table 1, which are clearly inferior to the samples made in other polyols. Thus, the preparation of polyols is necessary.
Comparative example 4
KFSF@CNTs prepared under high raw material concentration:
(1) 1g of carbon nano tube with the diameter of 10-30 nm and the length of 20-30 mu m is added into a mixed solvent of 20mL of concentrated nitric acid and 60mL of concentrated sulfuric acid, heated and stirred for 8h at the temperature of 70 ℃. Cooling, diluting with 400mL of deionized water, and separating by suction filtration;
(2) 200mg of acidified carbon nanotubes are added into 50mL of diethylene glycol solvent, and the mixture is subjected to ultrasonic treatment for 1h to obtain the carbon nanotube with the concentration of 4g L -1 Is a uniform carbon nanotube dispersion of (a).
(3) 5.56g FeSO 4 ·7H 2 O and 1.16g KF were added to the carbon nanotube dispersion, and the solution was stirred for 0.5h without sufficient dissolution, the theoretical concentration of both was 0.4mol L -1 ；
(4) The dispersion obtained in step (3) was added to a 100mL hydrothermal kettle, placed in an oil bath, heated to 160℃and kept at constant temperature for 6 hours while maintaining a magnetic stirring speed of 1500rpm. After cooling to room temperature, the obtained precipitate is separated by centrifugation, washed 3 times with acetone, and finally dried in vacuum at 80 ℃;
(5) Placing the precipitate obtained in the step (4) in a hydrogen-argon mixed gas tube furnace containing 5vol% of hydrogen at 3 ℃ for min -1 And (3) heating to 350 ℃ for calcining for 2 hours, and cooling to obtain the product.
The resulting KFSF@CNTs material was subjected to structural characterization and electrochemical performance testing in the same manner as in example 1. The XRD structure characterization is shown in FIG. 16, and it can be found that FeSO exists in the product 4 ·H 2 The impurity phase of O is mainly FeSO 4 ·7H 2 O does not dissolve sufficiently at high concentrations and is subsequently dehydrated during solvothermal processes. The results of the electrochemical performance test are shown in Table 1, which are clearly inferior to other samples prepared in the given concentration ranges.
TABLE 1 electrochemical performance data
Figure BDA0003506679640000121
/>

Claims (7)

1. KFESO (KFEESO) with carbon nano tube interpenetration 4 The preparation method of the F material is characterized by comprising the following steps:
(1) Acidifying the carbon nano tube and dispersing the acidified carbon nano tube in a polyalcohol solvent to obtain a carbon nano tube dispersion liquid; the polyol is diethylene glycol;
(2) Stirring and dissolving an iron source and potassium fluoride in the carbon nano tube dispersion liquid to obtain a mixed liquid; the iron source is FeSO 4 ·7H 2 O；
(3) Carrying out solvothermal reaction on the mixed solution in the step (2) to generate a precipitate; the solvothermal reaction temperature in the step (3) is 150-180 ℃ and the reaction time is 2-6 hours; the solvothermal reaction in the step (3) is carried out under the condition of stirring;
(4) Calcining the precipitate in the step (3) in a reducing atmosphere to obtain KFESO (KFES O) with carbon nanotubes inserted therein 4 F material; the calcination temperature is 350-380 ℃.
2. The carbon nanotube interpenetration of claim 1KFeSO 4 The preparation method of the F material is characterized in that in the step (2), the mass ratio of an iron source to potassium fluoride to carbon nano tubes is 1: 0.21-0.23: 0.036 to 0.072.
3. The carbon nanotube-interspersed kfeseo as claimed in claim 1 4 The preparation method of the F material is characterized in that the concentration of the carbon nano tube dispersion liquid in the step (1) is 1.0-2.0 g L −1 。
4. The carbon nanotube-interspersed kfeseo as claimed in claim 1 4 The preparation method of the F material is characterized in that the concentration of the iron source and the concentration of the potassium fluoride in the step (2) are both 0.1-0.2 mol L −1 。
5. The carbon nanotube-interspersed kfeseo as claimed in claim 1 4 The preparation method of the F material is characterized in that the diameter of the carbon nano tube in the step (1) is 10-50 nm, and the length of the carbon nano tube is 10-30 mu m.
6. The carbon nanotube-interspersed kfeseo as claimed in claim 1 4 The preparation method of the F material is characterized in that the reducing atmosphere in the step (4) is hydrogen-argon mixed gas, and the volume percentage of hydrogen in the hydrogen-argon mixed gas is 5-10%.
7. A carbon nanotube-interspersed kfeseo as claimed in any one of claims 1 to 6 4 KFESO (KFEESO) interspersed with carbon nanotubes prepared by preparation method of F material 4 The F material is applied as a positive electrode material of a potassium ion battery.
CN202210141854.6A 2022-02-16 2022-02-16 KFESO (KFEESO) with carbon nano tube interpenetration 4 Preparation method and application of F material Active CN114628623B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202210141854.6A CN114628623B (en) 2022-02-16 2022-02-16 KFESO (KFEESO) with carbon nano tube interpenetration 4 Preparation method and application of F material

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202210141854.6A CN114628623B (en) 2022-02-16 2022-02-16 KFESO (KFEESO) with carbon nano tube interpenetration 4 Preparation method and application of F material

Publications (2)

Publication Number Publication Date
CN114628623A CN114628623A (en) 2022-06-14
CN114628623B true CN114628623B (en) 2023-05-23

Family

ID=81898823

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202210141854.6A Active CN114628623B (en) 2022-02-16 2022-02-16 KFESO (KFEESO) with carbon nano tube interpenetration 4 Preparation method and application of F material

Country Status (1)

Country Link
CN (1) CN114628623B (en)

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113046768A (en) * 2021-03-15 2021-06-29 东北师范大学 Potassium vanadyl fluorophosphate, preparation method and application thereof, and potassium ion battery

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102282098B (en) * 2008-10-23 2014-12-10 国立科学研究中心 Method for producing inorganic compounds
WO2012111681A1 (en) * 2011-02-15 2012-08-23 住友化学株式会社 Sodium secondary battery electrode and sodium secondary battery
CN102332580B (en) * 2011-03-15 2013-11-27 中国科学院物理研究所 Fluorinated ferric sulfate salt compound as well as preparation method and application thereof
FR2997076B1 (en) * 2012-10-19 2014-12-26 Commissariat Energie Atomique COMPOSITE MATERIAL COMPRISING NANO-OBJECTS, IN PARTICULAR CARBON NANO-OBJECTS, PROCESS FOR PREPARING THE SAME, AND INK AND ELECTRODE COMPRISING THE MATERIAL
US20170373306A1 (en) * 2016-06-22 2017-12-28 Sharp Kabushiki Kaisha Carbon-metal/alloy composite material, synthesis method, and electrode including same
CN105958029B (en) * 2016-06-24 2018-06-05 合肥国轩高科动力能源有限公司 A kind of preparation method of composite cathode material of lithium ion battery lithium vanadate/carbon nanotubes/carbon
CN106602008B (en) * 2016-12-06 2019-08-23 广州汽车集团股份有限公司 The self-assembly preparation method thereof and manganese-lithium phosphate anode material of manganese-lithium phosphate anode material
CN107230779B (en) * 2017-05-03 2021-02-19 武汉理工大学 Preparation method of high-temperature stable phase-change type lithium iron fluorosulfate battery material, electrode plate and use method of lithium ion battery
CN109167047A (en) * 2018-09-19 2019-01-08 哈尔滨工业大学 Self-supporting three-dimensional grapheme/tin composite lithium ion battery cathode material preparation method
JP7281100B2 (en) * 2019-03-06 2023-05-25 学校法人東京理科大学 Electrolyte for potassium ion battery, potassium ion battery, electrolyte for potassium ion capacitor, and potassium ion capacitor

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113046768A (en) * 2021-03-15 2021-06-29 东北师范大学 Potassium vanadyl fluorophosphate, preparation method and application thereof, and potassium ion battery

Also Published As

Publication number Publication date
CN114628623A (en) 2022-06-14

Similar Documents

Publication Publication Date Title
CN110299516B (en) Preparation method of carbon nanotube array loaded lithium titanate flexible electrode material
CN102208631B (en) Ultra-long single crystal V2O5 nano wire/graphene anode material and preparation method
Bai et al. A large-scale, green route to synthesize of leaf-like mesoporous CuO as high-performance anode materials for lithium ion batteries
WO2022032743A1 (en) Cote2/mxene composite material and preparation method therefor
Su et al. Preparation and electrochemical Li storage performance of MnO@ C nanorods consisting of ultra small MnO nanocrystals
Liu et al. Preparing micro/nano dumbbell-shaped CeO2 for high performance electrode materials
Zhang et al. Self-assembled Co3O4 nanostructure with controllable morphology towards high performance anode for lithium ion batteries
WO2022032745A1 (en) Vo2/mxene composite material, preparation method therefor and use thereof
CN114335681B (en) Inorganic halide solid electrolyte, preparation method thereof, lithium ion battery and application
CN111769272A (en) Bi @ C hollow nanosphere composite material and preparation method and application thereof
Zhou et al. Sulfur-doped reduced graphene oxide/Sb2S3 composite for superior lithium and sodium storage
CN108550824B (en) Preparation method of high-capacity battery negative electrode material
CN112357956B (en) Carbon/titanium dioxide coated tin oxide nanoparticle/carbon assembled mesoporous sphere material and preparation and application thereof
Wang et al. Enhanced cyclic performance of Cu2V2O7/reduced Graphene Oxide mesoporous microspheres assembled by nanoparticles as anode for Li-ion battery
Fu et al. Graphene boosted Cu 2 GeS 3 for advanced lithium-ion batteries
Shi et al. Recycled silicon-based anodes with three-dimensional hierarchical porous carbon framework synthesized by a self-assembly CaCO3 template method for lithium ion battery
Zhang et al. Synthesis and Lithium Storage Performance of Mesoporous Co3O4 Microrods Derived From Co-Based Metal-Organic Framework
CN112928246A (en) Composite material, preparation method and application thereof
CN107959024B (en) Flaky Sb for sodium ion battery cathode2Se3Method for preparing nanocrystalline
CN108448085A (en) Lithium titanate-carbon nano tube compound material and preparation method thereof, lithium ion battery
Li et al. A ZnO/rice husk-based hollow carbonaceous nanosphere composite as an anode for high-performance lithium-ion batteries
CN114628623B (en) KFESO (KFEESO) with carbon nano tube interpenetration 4 Preparation method and application of F material
CN109103432B (en) Pyrovanadate/nitrogen-doped graphene composite material and preparation method and application thereof
CN115036505B (en) Carbon-coated germanium composite anode material for lithium ion battery and preparation method and application thereof
CN113782713B (en) MoS 2 Nano-sheet vertically embedded biological carbon nano composite material and preparation method and application thereof

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant