CN110943213B - MOF-derived porous carbon box loaded with Co 3 V 2 O 8 Composite negative electrode material and preparation method and application thereof - Google Patents

Abstract

The invention provides a composite material composed of one-dimensional rod-shaped Co ₃ V ₂ O ₈ loaded on a porous carbon box (Porous Carbon Box, PCB) obtained by pyrolysis of a Co-containing metal-organic framework compound (Metal-Organic Framework, MOF). Its preparation method and its application in lithium ion battery negative electrode material. The present invention prepares zeolitic imidazolate framework-67 (Zeolitic Imidazolate Frameworks-67, ZIF-67) with controllable morphology, and uses it as a template precursor to remove Co after high-temperature pyrolysis, and the obtained porous carbon box is Ultrasonic dispersion in the solution, followed by self-assembly with the porous carbon box as the internal skeleton, through a hydrothermal process, and Co ₃ V ₂ O ₈ was attached to the surface of the porous carbon box and embedded in the pores to form a composite material. The whole experimental process of the present invention does not generate toxic and dangerous substances, and the operation is simple and easy. Co ₃ V ₂ O ₈ @PCB has a high specific surface area and a porous structure, and through the synergistic effect of composite materials, the rate of lithium-ion batteries and It is an excellent negative electrode material for lithium-ion batteries.

Description

A MOF-derived porous carbon box loaded Co3V2O8 composite negative electrode material and its preparation method law and application

technical field

The invention relates to the technical field of preparation of lithium-ion battery electrode materials, in particular to a MOF-derived porous carbon box loaded Co ₃ V ₂ O ₈ composite negative electrode material and a preparation method and application thereof.

Background technique

In the face of increasingly severe environmental pollution and energy crisis, it is imperative to develop green, efficient and sustainable clean energy. Since the output energy of clean energy such as solar energy and wind energy requires a certain storage system to be practical, lithium-ion batteries, as secondary batteries with high-efficiency energy conversion and storage, have been continuously researched and developed, and applied to life and other fields. However, in the face of market requirements for high-energy energy storage systems and high capacity, the current electrochemical performance of lithium-ion batteries cannot be well met. Therefore, the development of a new generation of lithium ion battery electrode materials with high specific capacity, low price, safety and reliability has become the focus in the field of electrochemical research.

Metal oxide anode materials have been widely studied in lithium-ion batteries due to their abundant resources, low price, high charge-discharge specific capacity and better safety performance, but also because of their poor conductivity and easy pulverization and other defects. The cycle stability and rate performance of the material, so it is necessary to develop anode materials with better performance. The double metal oxide Co ₃ V ₂ O ₈ has a unique crystal structure, which has better synergistic electrochemical properties than single metal oxides, higher reversible capacity, and better stability. It is an ideal negative electrode material. There are good application prospects in ion batteries, but the cycle and rate performance need to be improved. MOF is an organic-inorganic hybrid material with adjustable porosity and large specific surface area. The present invention realizes the MOF-derived porous carbon box as the internal framework, and the one-dimensional rod-shaped Co ₃ V ₂ O ₈ is attached to the porous carbon box or embedded in its pores to form a composite material, which can significantly improve the cycle stability and rate performance of the battery , The charge-discharge reversible capacity has also been greatly improved, and it is an excellent anode material for lithium-ion batteries.

Contents of the invention

In view of the shortcomings of oxide materials such as poor conductivity, cycle stability and rate performance, the purpose of the present invention is to provide a composite material of a double transition metal oxide Co ₃ V ₂ O ₈ and a porous carbon box. The porous carbon box is obtained by pyrolysis of ZIF-67, and then the one-dimensional rod-like Co ₃ V ₂ O ₈ is attached to the porous carbon box or embedded in its pores to form a composite negative. Through this ingenious process design and shape control , to improve the electrochemical performance of the material.

In order to achieve the above-mentioned purpose of the invention, the present invention provides a MOF-derived porous carbon box loaded Co ₃ V ₂ O ₈ composite negative electrode material and a preparation method thereof. The preparation process includes the following steps:

Add the cobalt source and 2-methylimidazole to an appropriate amount of solvent and stir for 5-10 minutes to dissolve, then slowly add the 2-methylimidazole solution to the cobalt source solution and mix, keep stirring for 4-6 hours, then separate the precipitate and remove it with water and methanol After washing several times and drying, ZIF-67 was obtained; ZIF-67 was calcined and pyrolyzed at high temperature under a protective atmosphere, cooled to room temperature, washed with acid to extract Co, washed with water and ethanol several times, and dried to obtain a porous carbon box PCB.

Add metavanadate into deionized water, heat and stir for 5-10 minutes, add hydroxide to adjust pH, then add cobalt source and continue stirring for 10-20 minutes; then transfer the mixed solution to a stainless steel reaction kettle lined with polytetrafluoroethylene , cooling to room temperature after hydrothermal reaction; separating the precipitate, washing and drying to obtain the precursor; calcining the precursor in air atmosphere to obtain rod-shaped Co ₃ V ₂ O ₈ .

Thoroughly disperse the prepared porous carbon box PCB in water for 1~2h, add an appropriate amount of rod-shaped Co ₃ V ₂ O ₈ according to the ratio of PCB to Co and stir for 0.5~1h to make it evenly mixed; then transfer the mixture to polytetrafluoroethylene In an ethylene-lined stainless steel reactor, cool to room temperature after hydrothermal reaction; after precipitation and separation, wash with water and ethanol for 3 to 4 times and dry to obtain the Co ₃ V ₂ O ₈ @PCB composite material.

The Co ₃ V ₂ O ₈ @PCB composite material is a composite negative electrode material in which a porous carbon box is used as an internal skeleton, and one-dimensional rod-shaped Co ₃ V ₂ O ₈ is attached to the porous carbon box or embedded in its pores.

The preparation method of the porous carbon box loaded Co ₃ V ₂ O ₈ composite negative electrode material, the ratio of PCB to Co is 1:2~1:5 in molar ratio; the hydrothermal reaction temperature is 120~180°C, and the hydrothermal reaction time is 8~16h; precipitation separation method is one of filtration, suction filtration or centrifugal separation; drying is one of water bath heating evaporation, drying oven drying, vacuum drying, and the drying time is 6~10h.

The preparation method of the porous carbon box PCB, the cobalt source is one of cobalt chloride, cobalt nitrate, cobalt sulfate, cobalt acetate, cobalt oxalate or hydrate thereof; the solvent is one or more of water, ethanol, methanol The precipitation separation method is one of filtration, suction filtration or centrifugal separation; the protective atmosphere is one of nitrogen, argon, and helium; Insulate at 700~900°C for 1~2h; cooling to room temperature is one of program-controlled slow cooling, natural cooling, or quenching in liquid nitrogen; acid washing and leaching Co is hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, oxalic acid, acetic acid One or more of them are mixed; the drying method is one of water bath heating evaporation, drying oven drying, and vacuum drying, and the drying time is 6~10h.

The preparation method of the rod-shaped Co ₃ V ₂ O ₈ , the metavanadate is one of ammonium metavanadate, sodium metavanadate, potassium metavanadate; the hydroxide is sodium hydroxide, lithium hydroxide, hydrogen A kind of potassium oxide, adjust the pH to 10~11; the cobalt source is one of cobalt chloride, cobalt nitrate, cobalt sulfate, cobalt acetate, cobalt oxalate or its hydrate; the temperature of hydrothermal reaction is 160~200 ℃, time 12~24h; the precipitation separation method is one of filtration, suction filtration or centrifugal separation; the precursor is calcined in the air atmosphere at a heating rate of 3~5°C/min, rising to 450~550°C for 5 After ~8h, it was naturally cooled to room temperature.

The advantage of the present invention is that: after mixing and stirring Co ₃ V ₂ O ₈ and PCB in a certain proportion, the self-assembly of one-dimensional rod-shaped Co ₃ V ₂ O ₈ on the surface of the porous carbon box or its pores can be realized through the self-assembly of the hydrothermal process. The load inside, the experimental operation is simple, the price is low, the effect is obvious, and there is no toxic and harmful substances in the whole experimental process. Pickling ZIF-67 after pyrolytic carbonization not only increases the surface roughness and a large number of active sites, but also the cavities and vacancies left after pickling and stripping Co are more conducive to cobalt in terms of spatial size and bonding tendency. The oxide Co ₃ V ₂ O ₈ adheres closely to the surface or embeds in the interior of the porous carbon box structure through physical/chemical action. _On the one hand, the adhesion/embedding _of the Co ₃ V ₂ O ₈ nanorod particles _on the surface of the porous carbon box and in the pores is very tight. One-dimensional morphology characteristics are conducive to the rapid transport of ions and charges between particles and inside particles, thereby achieving excellent rate characteristics; Volume expansion and pulverization during charge-discharge cycles; thereby achieving better cycle performance; in addition, the composite material has a large specific surface area and a porous structure, with many active sites and is conducive to the infiltration of the electrolyte, which is conducive to Increase the reactivity of the material, reduce the internal resistance of the battery, and obtain a higher reversible capacity. In summary, the synergistic effect of the composite material makes it have excellent comprehensive electrochemical performance when applied to the anode material of lithium-ion batteries.

Description of drawings

FIG. 1 is an X-ray diffraction pattern of the Co ₃ V ₂ O ₈ @PCB composite material obtained in Example 1.

FIG. 2 is a scanning electron micrograph of rod-shaped Co ₃ V ₂ O ₈ particles obtained in Example 1.

3 is a scanning electron microscope image of ZIF-67 obtained in Example 1.

FIG. 4 is a scanning electron microscope image of the Co ₃ V ₂ O ₈ @PCB composite material obtained in Example 1.

Fig. 5 is the first charge and discharge curve of the Co ₃ V ₂ O ₈ @PCB composite material obtained in Example 2.

FIG. 6 is the cycle performance curve of the Co ₃ V ₂ O ₈ @PCB composite material obtained in Example 2.

FIG. 7 is a rate performance diagram of the Co ₃ V ₂ O ₈ @PCB composite material obtained in Example 2 at different current densities.

Detailed ways

In order to facilitate understanding of the present invention, the present invention will be further described in detail below in conjunction with specific embodiments and accompanying drawings. Apparently, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiment of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Example 1

This embodiment provides a MOF-derived porous carbon box loaded Co ₃ V ₂ O ₈ composite negative electrode material and its preparation method, including the following steps:

(1) Add cobalt nitrate hexahydrate and 2-methylimidazole to methanol and stir for 10 minutes to dissolve, then slowly add 2-methylimidazole solution to cobalt nitrate hexahydrate solution and mix, continue stirring for 6 hours, centrifuge to separate the precipitate and use After washing with ionized water and methanol for several times, ZIF-67 was obtained after drying in a drying oven at 60°C for 6 hours. Raise ZIF-67 to 800°C at a rate of 1°C/min under N ₂ and keep it warm for 2 hours. After cooling down to room temperature naturally, wash and extract Co with hydrochloric acid, wash with deionized water and ethanol several times, and place in a dry box. After drying at 60°C for 6 hours, a porous carbon box PCB was obtained;

(2) Add ammonium metavanadate to 50ml deionized water, heat and stir for 10 minutes, add sodium hydroxide to adjust the pH to 11, then add cobalt chloride hexahydrate and continue stirring for 20 minutes; then transfer the mixed solution to the polytetrafluoroethylene lining In a stainless steel reaction kettle, it was hydrothermally reacted at 200°C for 12 hours and cooled to room temperature naturally; the precipitate was separated by suction filtration and washed with deionized water, and then dried in a drying oven at 60°C for 8 hours to obtain the precursor, and then the precursor was placed in the air atmosphere Raise the temperature to 550°C at a rate of 5°C/min and hold it for 5 hours to obtain rod-shaped Co ₃ V ₂ O ₈ ;

(3) Thoroughly disperse the porous carbon box PCB obtained in step (1) in water for 1 h, and add Co ₃ V ₂ O ₈ obtained in step (2) according to the ratio of PCB to Co of 1:3 and stir for 0.5 h to make it uniform After mixing, the mixture was transferred to a polytetrafluoroethylene-lined stainless steel reactor, hydrothermally reacted at 160 °C for 12 h, and then cooled to room temperature naturally; the precipitate was separated by centrifugation and washed several times with deionized water and ethanol, and then placed in a drying oven Co ₃ V ₂ O ₈ @PCB composites were obtained after drying at 60℃ for 6h.

Example 2

This embodiment provides a MOF-derived porous carbon box loaded Co ₃ V ₂ O ₈ composite negative electrode material and its preparation method and application, including the following steps:

(1) Add cobalt acetate tetrahydrate and 2-methylimidazole respectively to a solution mixed with deionized water and methanol at a ratio of 1:1 and stir for 5 minutes to dissolve, then slowly add the 2-methylimidazole solution to cobalt nitrate hexahydrate Mixed in the solution, stirred continuously for 5 hours, centrifuged to separate the precipitate, washed several times with deionized water and methanol, and then dried under vacuum at 80°C for 4 hours to obtain ZIF-67. Raise ZIF-67 to 900°C under Ar with a heating rate of 2°C/min, then keep it warm for 1h, then slowly cool down to room temperature under program control, wash with nitric acid to extract Co, wash with water and ethanol for several times, and store in a drying oven at 80°C After drying for 6 hours, a porous carbon box PCB was obtained;

(2) Add sodium metavanadate to 50ml deionized water, heat and stir for 10 minutes, add sodium hydroxide to adjust the pH to 10, then add cobalt acetate tetrahydrate and continue stirring for 10 minutes, then transfer the mixed solution to the Teflon-lined In a stainless steel reaction kettle, after a hydrothermal reaction at 180°C for 14 hours, it was naturally cooled to room temperature, the precipitate was separated by suction filtration and washed several times with deionized water and ethanol, and then dried in a drying oven at 60°C for 8 hours to obtain a precursor, which was then placed in air In the atmosphere, the temperature was raised to 500°C at a rate of 5°C/min and kept for 6 hours to obtain rod-shaped Co ₃ V ₂ O ₈ ;

(3) Thoroughly disperse the PCB obtained in step (1) in water for 1 hour by ultrasonication, and add the Co ₃ V ₂ O ₈ obtained in step (2) according to the ratio of PCB to Co of 1:2 and stir for 0.5 hours to make it evenly mixed, and then The mixture was transferred to a polytetrafluoroethylene-lined stainless steel reactor, hydrothermally reacted at 180 °C for 12 h, cooled to room temperature, centrifuged to separate the precipitate and washed several times with deionized water and ethanol, and then dried in a drying oven at 60 °C After 6h, Co ₃ V ₂ O ₈ @PCB composite material was obtained;

(4) The above-mentioned Co ₃ V ₂ O ₈ @PCB composite material, acetylene black, and PVDF were completely mixed in N-methylpyrrolidone at a mass ratio of 7:2:1, and stirred for 2 hours until a slurry was formed. The stirred slurry was coated on the copper foil current collector with a surface density of 2 mg/cm ² , punched with a punching machine with a diameter of 16 mm, and dried in a vacuum oven for 12 hours. Then assemble the battery in the glove box. The battery case is 2032, the electrolyte is 1M LiPF6, and the solvent is a mixture of EC and DMC with a volume ratio of 1:1. After the assembly is completed, the battery is left to stand for more than 12 hours, and then the battery performance is tested using the Xinwei battery test system, and the cycle performance and the rate performance at different current densities are tested in the voltage range of 0.02~3V.

Example 3

This embodiment provides a MOF-derived porous carbon box loaded Co ₃ V ₂ O ₈ composite negative electrode material and its preparation method, including the following steps:

(1) Add cobalt chloride hexahydrate and 2-methylimidazole to ethanol and stir for 5 minutes to dissolve, then slowly add the 2-methylimidazole solution to the cobalt nitrate hexahydrate solution and mix, continue stirring for 5 hours, then centrifuge to separate the precipitate It was washed several times with deionized water and methanol, and then heated in a water bath at 60°C for 4 hours to obtain ZIF-67. The ZIF-67 was heated to 700°C at a rate of 2°C/min under Ar, then kept at 700°C for 2 hours, cooled naturally to room temperature, washed with phosphoric acid to extract Co, washed with deionized water and ethanol several times, and then placed in a dry box for 60 After drying at ℃ for 8 hours, the PCB was obtained;

(2) Add ammonium metavanadate to 50ml of deionized water, heat and stir for 15 minutes, add sodium hydroxide to adjust the pH to 11, then add cobalt nitrate hexahydrate and continue stirring for 20 minutes, then transfer the mixed solution to the polytetrafluoroethylene-lined In a stainless steel reaction kettle, after hydrothermal reaction at 180°C for 18 hours, cool to room temperature; the precipitate was separated by suction filtration and washed several times with deionized water and ethanol, and then dried in a drying oven at 60°C for 8 hours to obtain a precursor, and then the precursor was placed in the air In the atmosphere, the temperature was raised to 500°C at a rate of 3°C/min and kept for 6 hours to obtain rod-shaped Co ₃ V ₂ O ₈ ;

(3) Thoroughly disperse the PCB obtained in step (1) in water for 1 hour by ultrasonication, and add the Co ₃ V ₂ O ₈ obtained in step (2) according to the ratio of PCB to Co of 1:5 and stir for 0.5 hours to make it evenly mixed, and then The mixture was transferred to a polytetrafluoroethylene-lined stainless steel reactor, hydrothermally reacted at 140 °C for 12 h, cooled to room temperature, centrifuged to separate the precipitate and washed several times with deionized water and ethanol, and then dried in a drying oven at 60 °C After 6h, the Co ₃ V ₂ O ₈ @PCB composite material was obtained.

Example 4

This embodiment provides a MOF-derived porous carbon box loaded Co ₃ V ₂ O ₈ composite negative electrode material and its preparation method, including the following steps:

(1) Add cobalt sulfate heptahydrate and 2-methylimidazole to a solution mixed with methanol and deionized water at a ratio of 1:1 and stir for 10 minutes to dissolve, then slowly add the 2-methylimidazole solution to cobalt nitrate hexahydrate Mix in the solution, keep stirring for 5 hours, centrifuge the precipitate, wash with water and methanol for several times, and then vacuum dry at 80°C for 4 hours to obtain ZIF-67. Raise ZIF-67 to 800°C at a rate of 1°C/min under N ₂ and keep it warm for 1 hour. Slowly cool down to room temperature under program control, wash with oxalic acid to extract Co, wash with deionized water and ethanol for several times, and store After drying at 60°C for 8 hours, the PCB was obtained;

(2) Add sodium metavanadate to 50ml deionized water, heat and stir for 10 minutes, add lithium hydroxide to adjust the pH to 10, then add cobalt acetate tetrahydrate and continue stirring for 10 minutes, then transfer the mixed solution to the polytetrafluoroethylene-lined In a stainless steel reaction kettle, after a hydrothermal reaction at 180°C for 14 hours, it was naturally cooled to room temperature, the precipitate was separated by suction filtration and washed several times with deionized water and ethanol, and then dried in a drying oven at 60°C for 8 hours to obtain a precursor. In the air atmosphere, the temperature was raised to 500°C at a rate of 5°C/min and kept for 6 hours to obtain rod-shaped Co ₃ V ₂ O ₈ ;

(3) Ultrasonically disperse the PCB obtained in step (1) in water for 1 hour, add the Co ₃ V ₂ O ₈ obtained in step (2) according to the ratio of PCB to Co of 1:4 and stir for 0.5 hours to make it evenly mixed, and then The mixture was transferred to a polytetrafluoroethylene-lined stainless steel reaction kettle, hydrothermally reacted at 180 °C for 12 h, cooled to room temperature naturally, and the precipitate was centrifuged and washed several times with deionized water and ethanol, and then placed in a drying oven at 60 °C Co ₃ V ₂ O ₈ @PCB composites were obtained after drying for 6 hours.

Claims (3)

1. A method for preparing a MOF-derived porous carbon box loaded Co ₃ V ₂ O ₈ composite negative electrode material, characterized in that the prepared Co ₃ V ₂ O ₈ @PCB uses a porous carbon box as the internal skeleton, and is one-dimensional rod-shaped A composite negative electrode material in which Co ₃ V ₂ O ₈ is attached to a porous carbon box or embedded in its pores, and the preparation of the composite material includes the following steps: 1) Ultrasonically disperse the prepared porous carbon box PCB in water for 1~2h, add an appropriate amount of rod-shaped Co ₃ V ₂ O ₈ according to the ratio of PCB to Co, and stir for 0.5~1h to make it evenly mixed; 2) Transfer the mixed solution obtained in step 1) to a polytetrafluoroethylene-lined stainless steel reactor, and cool to room temperature after hydrothermal reaction; 3) Separate the precipitate obtained in step 2), wash it with water and ethanol for 3 to 4 times, and obtain the Co ₃ V ₂ O ₈ @PCB composite material after drying; The ratio of PCB to Co in step 1) is a molar ratio of 1:2~1:5; the hydrothermal reaction temperature in step 2) is 120~180°C, and the hydrothermal reaction time is 8~16h ; The precipitation separation method described in step 3) is one of filtration, suction filtration or centrifugal separation; the drying is one of water bath heating evaporation, drying oven drying, and vacuum drying, and the drying time is 6~10h; The preparation method of the porous carbon box PCB described in step 1), the steps are as follows: 4) Add the cobalt source and 2-methylimidazole to an appropriate amount of solvent and stir for 5-10 minutes to dissolve, then slowly add the 2-methylimidazole solution to the cobalt source solution and mix, and continue stirring for 4-6 hours; 5) Separate the precipitate precipitated from the mixed solution obtained in step 4), wash with deionized water and methanol several times, and obtain ZIF-67 after drying; 6) The ZIF-67 obtained in step 5) was calcined and pyrolyzed at high temperature under a protective atmosphere, cooled to room temperature, washed with acid to extract Co, washed with deionized water and ethanol several times, and dried to obtain PCB; The cobalt source in step 4) is one of cobalt chloride, cobalt nitrate, cobalt sulfate, cobalt acetate, cobalt oxalate or their hydrates; the solvent is one or more of water, ethanol, methanol mixed ; The precipitation separation method described in step 5) is one of filtration, suction filtration or centrifugal separation; the protective atmosphere described in step 6) is one of nitrogen, argon, and helium; the high-temperature calcination pyrolysis The condition is that the heating rate is 1~5°C/min, and the temperature is kept at 700~900°C for 1~2h; the cooling to room temperature is one of program controlled slow cooling, natural cooling or quenching in liquid nitrogen; the washing with acid The acid for leaching Co is one or more mixtures of hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, oxalic acid, and acetic acid; the drying method is one of water bath heating evaporation, drying oven drying, and vacuum drying, and the drying time is 6 ~10h; The preparation method of rod-shaped Co ₃ V ₂ O ₈ described in step 1), the steps are as follows: 7) Add metavanadate into deionized water, heat and stir for 5~10min, add hydroxide to adjust pH, then add cobalt source and continue stirring for 10~20min; 8) Transfer the mixed solution obtained in step 7) to a polytetrafluoroethylene-lined stainless steel reactor, and cool to room temperature after hydrothermal reaction; 9) The precipitate obtained in step 8) is separated, washed and dried to obtain a precursor, and the obtained precursor is calcined in an air atmosphere to obtain rod-shaped Co ₃ V ₂ O ₈ ; The metavanadate described in step 7) is one of ammonium metavanadate, sodium metavanadate and potassium metavanadate; the hydroxide is one of sodium hydroxide, lithium hydroxide and potassium hydroxide species; adjust the pH to 10~11; the cobalt source is one of cobalt chloride, cobalt nitrate, cobalt sulfate, cobalt acetate, cobalt oxalate or hydrate thereof; the hydrothermal reaction temperature described in step 8) is 160 ~200°C, the time is 12~24h; the precipitation separation method described in step 9) is one of filtration, suction filtration or centrifugal separation; the calcination condition of the precursor in the air atmosphere is that the heating rate is 3~5°C /min, rise to 450~550℃ and keep warm for 5~8h, then cool down to room temperature naturally. 2. A MOF derived porous carbon box loaded Co ₃ V ₂ O ₈ composite material obtained by the preparation method according to claim 1. 3. The application of a MOF derived porous carbon box as claimed in claim 1 supporting Co ₃ V ₂ O ₈ composite material as a lithium ion battery negative electrode material, characterized in that: Co ₃ V ₂ O ₈ @PCB composite material is used as an active The substance, the conductive agent and the binder are mixed in the N-methylpyrrolidone dispersant in a certain proportion, fully stirred to form a slurry, coated on the surface of the copper foil current collector, dried and cut into a certain shape of the pole piece; the prepared The pole piece is used as a negative electrode, and a lithium-ion battery is assembled with a positive electrode, an electrolyte, and a diaphragm, or the pole piece is used as a positive electrode, and an experimental half-cell is assembled with a counter electrode metal lithium, an electrolyte, and a diaphragm; the battery is assembled at a current density of Charge and discharge at a constant current of 0.5 A/g, based on the reversible mass specific capacity of the active material can reach more than 1000 mAh/g.

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