A Co x P@N-C / CC flexible integrated lithium ion battery negative electrode material, preparation method and application thereof

Abstract

This invention discloses a Co x P@N-C / CC Flexible Integrated Lithium-ion Battery Anode Material, Its Preparation Method and Application, Cobalt Phosphate (Co) Formed on the Surface of a Flexible Carbon Material Matrix (CC) x The composite layer is doped with P and N-C, and has a line-sheet interwoven morphology; among which, cobalt phosphide Co x In P, 1 < x < 2. The method of this invention synthesizes a cobalt-containing precursor grown in situ on carbon cloth via hydrothermal synthesis. The dopamine-coated cobalt precursor on the carbon cloth undergoes low-temperature gas-phase phosphating. During the phosphating process, the outer dopamine coating is carbonized, thereby obtaining Co. x P@N-C / CC flexible integrated electrode. This invention, Co... x The P@N-C / CC self-supporting flexible electrode can be directly sliced ​​as a negative electrode for lithium-ion batteries and has a unique interwoven wire-sheet morphology structure. This structure can effectively enhance ion transport, and the nitrogen-doped carbon outer layer can improve the conductivity of the material and alleviate the volume expansion of the material during charging and discharging. Therefore, it achieves high capacity and high stability electrochemical performance.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of preparation high capacity and high stability performance with unique wire sheet interlaced morphology structure lithium ion battery negative material, its method and application, the present application belongs to Co x The preparation field of flexible negative electrode. BACKGROUND

[0002] With the rapid development of portable, flexible wearable electronic devices, flexible lithium ion batteries have attracted the attention of researchers. As one of the key components of flexible lithium ion batteries, the negative electrode material has higher requirements for its high capacity, cycle stability and flexibility.

[0003] Lithium ion battery negative materials are mainly divided into carbon-based materials, alloying reaction materials, metal oxides, metal sulfides and metal phosphides. Metal phosphides have relatively high theoretical capacity, electrical conductivity and lower polarization potential, and have attracted the attention of researchers in recent years. Among many metal phosphides, cobalt phosphide (CoP) has attracted much attention because of its multiple thermodynamically stable crystal structures, high theoretical capacity, suitable working voltage, low cost and other advantages. x P y ,x=1,2;y=1,2,3,4) because of its multiple thermodynamically stable crystal structures, high theoretical capacity, suitable working voltage, low cost and other advantages.

[0004] In recent years, several studies have reported the preparation of cobalt phosphide as a lithium ion battery negative material, but the poor electrical conductivity and large volume expansion limit its electrochemical performance, and the material obtained by preparation is mostly in the form of solid powder. The electrode prepared by coating the powder material on the current collector is easy to cause the electrode material to separate from the current collector when folded and bent, and is easy to powder during the charging and discharging process, resulting in serious capacity decay. The method of in-situ growth of active material on carbon cloth substrate can not only obtain an electrode with excellent flexibility to meet the needs of flexible lithium ion batteries, but also prevent material from separating and powdering. In addition, the wire sheet interlaced morphology structure and the nitrogen-doped carbon outer layer can effectively enhance ion transport, improve electrical conductivity and alleviate volume expansion, thereby further improving the electrochemical performance. SUMMARY

[0005] To solve the problems of the prior art, the purpose of the present application is to overcome the shortcomings of the prior art, and to provide a Co x P@N-C / CC flexible integrated lithium ion battery negative material, its preparation method and application, the material of the present application has a unique wire sheet interlaced morphology structure, has high capacity, high stability of lithium ion battery performance, the material of the present application as lithium ion battery negative electrode can enhance ion transport, improve electrical conductivity, effectively alleviate the volume expansion problem of the material during the cycle process, so that it has high capacity and high stability.

[0006] To achieve the above-mentioned purposes, the present application adopts the following technical solutions:

[0007] A Co x The P@N-C / CC flexible integrated lithium ion battery negative electrode material is formed on the surface of the tangible flexible carbon material matrix material CC x The P and N-C doped composite material layer has a wire piece interweaving morphology structure; wherein, the cobalt phosphide Co x 1 < x < 2 in P.

[0008] A Co x The preparation method of the P@N-C / CC flexible integrated lithium ion battery negative electrode material comprises the following steps:

[0009] a) a mixed solution of cobalt salt and precipitant CO(NH2)2 is prepared by using a solvent, and then carbon cloth is immersed in the mixed solution, and a cobalt-containing precursor in-situ grown on the carbon cloth is synthesized by a hydrothermal synthesis method;

[0010] b) the cobalt-containing precursor grown on the carbon cloth obtained is immersed in a Tris-HCl buffer solution of hydrochloric acid dopamine, and then stirred to obtain a dopamine-coated cobalt precursor with a black surface on the carbon cloth;

[0011] c) the dopamine-coated cobalt precursor obtained in the step b) is placed in a tube furnace, sodium hypophosphite is used as a phosphorus source for low-temperature gas phase phosphorization, and the outer layer of dopamine is carbonized at the same time at the temperature of the phosphorization treatment, and finally Co x P@N-C / CC flexible integrated lithium ion battery negative electrode material.

[0012] Preferably, in the step a), the molar concentration ratio of cobalt salt to precipitant in the mixed solution is 1:2-1:6; and the solvent used in the mixed solution is a mixed solution of deionized water and anhydrous ethanol, wherein the volume ratio of deionized water to anhydrous ethanol is 1:3-3:1.

[0013] Preferably, in the step a), the cobalt salt uses at least one of Co(NO3)2·6H2O, CoCl2·6H2O and CoSO4·7H2O.

[0014] Preferably, in the step a), the temperature of the hydrothermal reaction is 100-130℃, and the reaction time is 7-12h.

[0015] Preferably, in the step b), the mixing ratio of dopamine hydrochloride and Tris-HCl buffer solution is 20-50 mg: 40-100 mL, and the stirring time is 10-36 h; the Tris concentration of the Tris-HCl buffer solution is 2-5 mM.

[0016] Preferably, in the step c), the low-temperature gas-phase phosphorization is carried out according to the mass ratio of the dopamine-coated cobalt precursor in the step b) to the phosphorus source of 1:10-1:40, the phosphorus source is sodium hypophosphite, the temperature condition of phosphorization is 300-400 DEG C, the phosphorization time is 2-4 h, and the gas used is any one or a mixture of nitrogen and argon.

[0017] A Co x The application of the P@N-C / CC flexible integrated lithium ion battery negative electrode material is applied to the preparation of a lithium ion battery, which comprises a positive electrode, a negative electrode, a separator and an electrolyte, and the negative electrode is the Co x The P@N-C / CC flexible integrated lithium ion battery negative electrode material is prepared.

[0018] Preferably, the lithium ion battery is subjected to charge-discharge cycle test at a current density of 0.2 A / g, and the capacity is stably maintained at not less than 1018 mAh / g after 120 cycles.

[0019] Further preferably, the lithium ion battery is subjected to charge-discharge cycle test at a current density of 0.2 A / g, and the capacity is stably maintained at not less than 1169.1 mAh / g after 120 cycles.

[0020] Compared with the prior art, the application has the following obvious substantial characteristics and advantages:

[0021] 1. The self-supporting flexible integrated electrode obtained by growing active substances in situ with carbon cloth as a substrate has excellent flexibility, meets the needs of flexible batteries, and can prevent active substances from separating from the current collector during the electrochemical reaction process.

[0022] 2. The morphology structure of the wire sheet interweaving can effectively enhance ion transmission, and the outer layer of nitrogen-doped carbon can improve the conductivity of the material and relieve the volume expansion of the material during the charge-discharge process, thereby further realizing high capacity and high cycle stability.

[0023] Experiments show that, at a current density of 0.2 A / g, the capacity is stably maintained at 1169.1 mAh / g after 120 cycles of charge-discharge test;

[0024] 3. The method is simple, easy to implement and low in cost, and is suitable for popularization and use. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Of course, the drawings in the following description are only embodiments of the present application, and those skilled in the art can also obtain other drawings according to the provided drawings without creative labor.

[0026] Figure 1 The XRD pattern of the negative electrode material in Example 1 of the present application.

[0027] Figure 2 The SEM pattern of the negative electrode material in Example 1 of the present application.

[0028] Figure 3 The flexibility display diagram of the negative electrode material in Example 1 of the present application.

[0029] Figure 4 The Raman spectrum of the negative electrode material in Example 1 of the present application.

[0030] Figure 5 The charge-discharge cycle test of the lithium ion battery in Example 1 of the present application at a current density of 0.2 A / g.

[0031] Figure 6 The charge-discharge cycle test of the lithium ion battery in Example 2 of the present application at a current density of 0.2 A / g.

[0032] Figure 7 The charge-discharge cycle test of the lithium ion battery in Example 3 of the present application at a current density of 0.2 A / g. DETAILED DESCRIPTION

[0033] The above solutions will be further described in combination with specific examples. The preferred embodiments of the present application are described in detail as follows: The present application provides a method for preparing Co x The method for preparing P@N-C / CC (1 < x < 2) flexible integrated negative electrode and the high-capacity and high-stability lithium ion battery performance. It comprises the following steps:

[0034] a) configuring a mixed solution of a certain molar concentration ratio of cobalt salt (Co (NO3) 2·6H2O, CoCl2·6H2O, CoSO4·7H2O, etc.) and precipitating agent CO (NH2) 2, immersing carbon cloth into the mixed solution, and then synthesizing cobalt-containing precursor in-situ grown on carbon cloth through hydrothermal synthesis method; the cobalt salt in the mixed solution includes all the above-mentioned cobalt salts.

[0035] b) the obtained cobalt-containing precursor grown on carbon cloth is immersed in a Tris-HCl buffer solution of a certain mass of dopamine hydrochloride, and then stirred for a certain time to obtain a dopamine-coated cobalt precursor with a black surface on the carbon cloth.

[0036] c) the dopamine-coated cobalt precursor obtained in step b) is placed in a tube furnace, and low-temperature gas phosphating is performed using sodium hypophosphite as a phosphorus source at a certain mass ratio, and at the same time, the outer layer of coated dopamine is carbonized at the temperature of the phosphating treatment, and finally Co x P@N-C / CC (1 < x < 2) flexible integrated lithium ion battery negative electrode.

[0037] The present application provides a kind of Co x P@N-C / CC (1 < x < 2) flexible integrated negative electrode method and high capacity, high stability lithium ion battery performance.

[0038] The self-supporting flexible integrated electrode prepared by the present application has excellent flexibility, meets the needs of flexible batteries, and can prevent active materials from separating from the current collector. In addition, the morphology structure of the wire sheet interweaving can effectively enhance ion transport, and the outer layer of the nitrogen-doped carbon coating can improve the electrical conductivity of the material and alleviate the volume expansion of the material during charging and discharging, thereby further realizing high capacity and high cycle stability.

[0039] The present application provides a kind of lithium ion battery, including positive electrode, negative electrode, diaphragm and electrolyte, the negative electrode includes the self-supporting flexible lithium ion battery negative electrode material of the application.

[0040] The present application does not have special restrictions on the types of electrode, diaphragm and electrolyte. Specifically: the positive electrode can use lithium sheet; the negative electrode directly uses the synthesized self-supporting flexible integrated electrode; the diaphragm can use polypropylene microporous membrane; the electrolyte can use a mixture of 1M LiPF6 three-component mixed solvent EC: DMC: EMC = 1: 1: 1 and 1% FEC, and assemble into CR2016 simulation battery.

[0041] The present application uses 0.2A / g current for constant current charge and discharge experiment, tests the cycle performance of the lithium ion battery, and the charge and discharge voltage range is 0.01~3V. The CT2001A battery test system of Wuhan Blue Light Electronics Co., Ltd. is used to test the electrochemical performance of the battery, and the test is carried out at room temperature. The results show that the lithium ion battery in the present application has ultra-high capacity and excellent stability, and the capacity is stably maintained at 1169.1mAh / g after 120 cycles at a current density of 0.2A / g.

[0042] The preferred cobalt salt of the present application is Co(NO3)2·H2O, the substance playing the role of precipitant is CO(NH2)2, the molar concentration ratio is preferably 1:4, the ratio of the solvents deionized water and anhydrous ethanol is preferably 1:1, the temperature condition of the hydrothermal reaction is preferably 100 DEG C, and the time condition is preferably 6h. The molar concentration of the Tris-HCl buffer solution is preferably 2.5mM, the volume is 50mL, the mass of dopamine hydrochloride is 25mg, and the stirring time is 14h. The ratio of the dopamine-coated cobalt precursor to the phosphorus source is preferably 1:20, the temperature condition is preferably 350 DEG C, the time condition is 3h, and the gas is preferably nitrogen.

[0043] In order to further illustrate the present application, the following examples provide a method for preparing a Co x The method for preparing a P@N-C / CC (1

[0044] Example 1

[0045] In this embodiment, a Co x The P@N-C / CC flexible integrated lithium ion battery negative material is formed on the surface of the tangible flexible carbon material matrix material CC, and the cobalt phosphide Co x The P and N-C doped composite layer has a wire sheet interlaced morphology structure; wherein the cobalt phosphide Co x 1

[0046] A Co x The preparation method of the P@N-C / CC flexible integrated lithium ion battery negative material comprises the following steps:

[0047] a) a mixed solution of Co(NO3)2·H2O and CO(NH2)2 with a molar concentration ratio of 1:4 is prepared, the solvent is deionized water and anhydrous ethanol with a volume ratio of 1:1, and after stirring uniformly, it is transferred to the inner liner of a reaction kettle, and the pretreated carbon cloth is inclinedly placed therein, and then a hydrothermal synthesis method is used to synthesize a cobalt-containing precursor in situ grown on the carbon cloth at 100 DEG C for 8h;

[0048] b) 25mg of dopamine hydrochloride is weighed and dispersed into a prepared 50mL Tris-HCl buffer solution with a Tris concentration of 2.5mM, the obtained cobalt-containing precursor grown on the carbon cloth is immersed in the dopamine hydrochloride Tris-HCl buffer solution, and then stirring is carried out for 14h to obtain a dopamine-coated cobalt precursor with a black surface on the carbon cloth;

[0049] c) taking out the product, dopamine-coated cobalt precursor, obtained after the above treatment in step b), repeatedly washing the dopamine-coated cobalt precursor with deionized water and drying, and then placing the dopamine-coated cobalt precursor in a tube furnace, reacting at 350°C for 3h in a nitrogen atmosphere, using sodium hypophosphite as a phosphorus source, at a mass ratio of dopamine-coated cobalt precursor to phosphorus source of 1:20, to perform low-temperature gas-phase phosphorization, and at the same time, carbonizing the outer layer coated dopamine at the temperature of the phosphorization treatment, to finally obtain Co x P@N-C / CC self-supporting flexible integrated electrode material.

[0050] Experimental test analysis:

[0051] The XRD of the final product of the present embodiment is shown in Figure 1 The characteristic peaks correspond to CoP (JCPDS: 29-0497) and Co2P (JCPDS: 32-0306). The scanning electron microscope image is shown in Figure 2 The field presents a structure of interwoven wire sheets. The self-supporting flexible electrode prepared is subjected to bending test, as shown in Figure 3 It is found that the material has good flexibility. The product prepared is subjected to Raman test, and it can be seen from Figure 4 It can be seen that A D / A G = 3.34, indicating that there are many defects in the material. The product is subjected to charge and discharge cycle test, and the results are shown in Figure 5 After 120 cycles at 0.2A / g, the capacity is maintained at 1169.1 mAh / g, showing ultra-high capacity and excellent cycle stability.

[0052] The self-supporting flexible integrated electrode obtained by in-situ growth of active material using carbon cloth as substrate in the present embodiment has excellent flexibility, meets the needs of flexible batteries, and can prevent the active material from separating from the current collector during the electrochemical reaction. In addition, the morphology structure of interwoven wire sheets in the present embodiment can effectively enhance ion transmission, and the outer layer of nitrogen-doped carbon can improve the conductivity of the material and relieve the volume expansion of the material during charge and discharge, thereby further realizing high capacity and high cycle stability.

[0053] Example 2

[0054] The present embodiment is basically the same as Example 1, and the particularity lies in that:

[0055] In the present embodiment, a Co x P@N-C / CC flexible integrated lithium ion battery negative electrode material preparation method, comprising the following steps:

[0056] a) A mixed solution of Co(NO3)2·H2O and CO(NH2)2 with a molar concentration ratio of 1:5 is prepared, the solvent is deionized water and anhydrous ethanol with a volume ratio of 1:1, and after stirring uniformly, it is transferred into the inner liner of the reaction kettle, and the pretreated carbon cloth is placed obliquely therein, and then a cobalt-containing precursor in-situ grown on the carbon cloth is synthesized by a hydrothermal synthesis method at 110℃ for 9h;

[0057] b) 20mg of dopamine hydrochloride is weighed and dispersed in the prepared 40mL Tris-HCl buffer solution with a Tris concentration of 2.0mM, the cobalt-containing precursor grown on the carbon cloth is immersed in the dopamine hydrochloride Tris-HCl buffer solution, and then stirring is carried out for 16h to obtain a dopamine-coated cobalt precursor with a black surface on the carbon cloth;

[0058] c) The dopamine-coated cobalt precursor obtained after the above treatment in step b) is taken out, and the dopamine-coated cobalt precursor is repeatedly washed with deionized water and dried, and then the dopamine-coated cobalt precursor is placed in a tube furnace, sodium hypophosphite is used as a phosphorus source, the mass ratio of the dopamine-coated cobalt precursor to the phosphorus source is 1:15, and the reaction is carried out at 400℃ for 2h in a nitrogen atmosphere to perform low-temperature gas-phase phosphorization, and at the same time, the outer layer coated dopamine is carbonized at the phosphorization temperature, and finally a Co x P@N-C / CC self-supporting flexible integrated electrode material.

[0059] Experiments show that, as shown in Figure 6 the capacity is stably maintained at 1088mAh / g after 120 cycles at a current density of 0.2A / g. The self-supporting flexible integrated electrode obtained by using carbon cloth as a substrate to in-situ grow active substances in this embodiment has excellent flexibility, meets the needs of flexible batteries, and can prevent active substances from separating from the current collector during the electrochemical reaction. In addition, the morphology structure of the wire sheet interweaving in this embodiment can effectively enhance ion transmission, and the outer layer of nitrogen-doped carbon can improve the conductivity of the material and relieve the volume expansion of the material during the charging and discharging process, thereby further realizing high capacity and high cycle stability.

[0060] Embodiment 3

[0061] This embodiment is basically the same as the above-mentioned embodiments, and the particularity lies in that:

[0062] In this embodiment, a Co x The preparation method of the P@N-C / CC flexible integrated lithium ion battery negative electrode material comprises the following steps:

[0063] a) a mixed solution of Co(NO3)2.H2O and CO(NH2)2 with a molar concentration ratio of 1:3 is prepared, the solvent is deionized water and anhydrous ethanol with a volume ratio of 1.5:1, and after stirring uniformly, the mixed solution is transferred into the inner liner of a reaction kettle, and the pretreated carbon cloth is placed obliquely in the inner liner, and then a cobalt-containing precursor in-situ grown on the carbon cloth is synthesized by a hydrothermal synthesis method at 120 DEG C for 10 hours of hydrothermal reaction;

[0064] b) 30mg of dopamine hydrochloride is weighed and dispersed in the prepared 80mL Tris-HCl buffer solution with a Tris concentration of 3.0mM, the cobalt-containing precursor grown on the carbon cloth is immersed in the Tris-HCl buffer solution of dopamine hydrochloride, and then stirring is carried out for 18 hours to obtain a dopamine-coated cobalt precursor with a black surface on the carbon cloth;

[0065] c) the dopamine-coated cobalt precursor obtained after the above treatment in the step b) is taken out, the dopamine-coated cobalt precursor is repeatedly washed with deionized water and dried, and then the dopamine-coated cobalt precursor is placed in a tube furnace, sodium hypophosphite is used as a phosphorus source, the mass ratio of the dopamine-coated cobalt precursor to the phosphorus source is 1:25, and the reaction is carried out at 300 DEG C for 4 hours in a nitrogen atmosphere to perform low-temperature gas-phase phosphorization, and at the same time, the outer coated dopamine is carbonized at the phosphorization temperature, and finally the Co x P@N-C / CC self-supporting flexible integrated electrode material is obtained.

[0066] Experiments show that, as shown in Figure 7 the capacity is stably maintained at 1018mAh / g after 120 cycles of charge and discharge tests at a current density of 0.2A / g. The self-supporting flexible integrated electrode obtained by in-situ growth of active substances on the carbon cloth in the embodiment has excellent flexibility, meets the needs of flexible batteries, and can prevent the active substances from separating from the current collector during the electrochemical reaction. In addition, the morphology structure of the line sheet interweaving in the embodiment can effectively enhance the ion transmission, and the outer layer of the nitrogen-doped carbon can improve the conductivity of the material and relieve the volume expansion of the material during the charge and discharge process, thereby further realizing high capacity and high cycle stability.

[0067] The Co xThe P@N-C / CC flexible integrated negative electrode has high capacity and high stable lithium ion battery performance. The above-mentioned embodiment method comprises the following steps: preparing a mixed solution of a certain molar concentration ratio of a cobalt salt and a precipitant CO(NH2)2, then immersing carbon cloth into the mixed solution, and then synthesizing a cobalt-containing precursor in-situ grown on the carbon cloth by a hydrothermal synthesis method. The cobalt salt comprises all the above-mentioned cobalt compounds; then immersing the obtained cobalt-containing precursor grown on the carbon cloth into a Tris-HCl buffer solution of a certain mass of hydrochloric acid dopamine, stirring for a certain time, obtaining dopamine-coated cobalt precursor on the carbon cloth; then performing low-temperature gas phase phosphorization on the obtained dopamine-coated cobalt precursor on the carbon cloth by using sodium hypophosphite as a phosphorus source, and the outer coated dopamine is carbonized at the same time of the phosphorization treatment, and then Co x The P@N-C / CC flexible integrated electrode is used for a lithium ion electrode negative electrode. The Co x The P@N-C / CC self-supporting flexible electrode can be directly sliced as a lithium ion battery negative electrode, and has a unique wire piece interlaced morphology structure, which can effectively enhance ion transmission, and the outer nitrogen-doped carbon layer can improve the conductivity of the material and relieve the volume expansion of the material in the charging and discharging process, so that high capacity and high stability of the electrochemical performance are realized. Experiments show that the Co x The lithium ion battery assembled by the P@N-C / CC flexible integrated electrode has high capacity and good stability. Compared with the prior art, the preparation operation of the present application is simple and the cost is low, and the obtained Co x The P@N-C / CC flexible integrated electrode has excellent electrochemical performance and good flexibility, and meets the needs of flexible batteries and can be expanded for application in other flexible electronic devices.

[0068] The above describes the embodiments of the present application in combination with the drawings, but the present application is not limited to the above-mentioned embodiments, and can be changed in various ways according to the purpose of the present application. Any change, modification, replacement, combination or simplification made according to the spirit and principles of the present application shall be an equivalent replacement mode, as long as it meets the purpose of the present application, as long as it does not deviate from the technical principles and inventive concept of the present application.

Claims

1. A Co x P@NC / CC flexible integrated lithium-ion battery anode material, characterized in that: Cobalt phosphide (Co) is formed on the surface of a tangible, flexible carbon material matrix (CC). x The composite layer is doped with P and NC, and has a line-sheet interwoven morphology; among which, cobalt phosphide Co x In P, 1 < x < 2, and Co x The P@NC / CC flexible integrated lithium-ion battery anode material is prepared using the following method: First, a mixed solution of cobalt salt and precipitant CO(NH2)2 is prepared. Then, carbon cloth is immersed in this mixed solution, and a cobalt-containing precursor grown in situ on the carbon cloth is synthesized via hydrothermal synthesis. Next, the cobalt-containing precursor grown on the carbon cloth is immersed in a Tris-HCl buffer solution of dopamine hydrochloride and stirred to obtain a dopamine-coated cobalt precursor on the carbon cloth. Then, the dopamine-coated cobalt precursor on the carbon cloth is subjected to low-temperature gas-phase phosphating using sodium hypophosphite as the phosphorus source. During the phosphating process, the outer dopamine coating is carbonized, thereby obtaining Co. x P@NC / CC flexible integrated electrode material, used in lithium-ion electrode anodes.

2. The Co as described in claim 1 x The method for preparing P@NC / CC flexible integrated lithium-ion battery anode material is characterized by... Includes the following steps: a) A mixed solution of cobalt salt and precipitant CO(NH2)2 was prepared using a solvent. Then, carbon cloth was immersed in this mixed solution, and a cobalt-containing precursor grown in situ on the carbon cloth was synthesized by a hydrothermal synthesis method. b) The cobalt-containing precursor grown on carbon cloth was immersed in a Tris-HCl buffer solution of dopamine hydrochloride and then stirred to obtain a cobalt precursor with a black dopamine coating on the surface of the carbon cloth. c) The dopamine-coated cobalt precursor obtained in step b) is placed in a tube furnace, and low-temperature gas-phase phosphating is performed using sodium hypophosphite as the phosphorus source. Simultaneously, the outer dopamine coating is carbonized at the phosphating temperature to obtain Co. x P@NC / CC flexible integrated lithium-ion battery anode material.

3. The Co according to claim 2 x The method for preparing P@NC / CC flexible integrated lithium-ion battery anode material is characterized by... In step a), the molar ratio of cobalt salt to precipitant in the mixed solution is 1:2 to 1:6; the solvent used in the mixed solution is a mixture of deionized water and anhydrous ethanol, wherein the volume ratio of deionized water to anhydrous ethanol is 1:3 to 3:

1.

4. The Co according to claim 2 x The method for preparing P@NC / CC flexible integrated lithium-ion battery anode material is characterized by... In step a), the cobalt salt is at least one of Co(NO3)2·6H2O, CoCl2·6H2O, and CoSO4·7H2O.

5. The Co according to claim 2 x The method for preparing P@NC / CC flexible integrated lithium-ion battery anode material is characterized by... In step a), the temperature of the hydrothermal reaction is 100~130 ℃ and the reaction time is 7~12 h.

6. The Co according to claim 2 x The method for preparing P@NC / CC flexible integrated lithium-ion battery anode material is characterized by... In step b), the mixing ratio of dopamine hydrochloride and Tris-HCl buffer solution is 20-50 mg: 40-100 mL, and the stirring time is 10-36 h; the Tris concentration of the Tris-HCl buffer solution is 2-5 mM.

7. The Co according to claim 2 x The method for preparing P@NC / CC flexible integrated lithium-ion battery anode material is characterized by... In step c), low-temperature gas-phase phosphating is performed with a mass ratio of dopamine-coated cobalt precursor to phosphorus source of 1:10 to 1:40 obtained in step b). Sodium hypophosphite is used as the phosphorus source. The phosphating temperature is 300 to 400°C and the phosphating time is 2 to 4 hours. The gas used is any one of nitrogen and argon or a mixture of both.

8. The Co as described in claim 1 x The application of P@NC / CC flexible integrated lithium-ion battery anode material, used in the fabrication of lithium-ion batteries, including positive electrode, negative electrode, separator, and electrolyte, is characterized by: The negative electrode uses the Co as described in claim 1. x P@NC / CC flexible integrated lithium-ion battery anode material is used.

9. The application according to claim 8, characterized in that: The lithium-ion battery was subjected to charge-discharge cycle testing at a current density of 0.2 A / g, and after 120 cycles, its capacity remained stable at no less than 1018 mAh / g.

10. The application according to claim 9, characterized in that: The lithium-ion battery was subjected to charge-discharge cycle testing at a current density of 0.2 A / g, and after 120 cycles, the capacity remained stable at no less than 1169.1 mAh / g.

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