A hollow aculeiform globular phosphorus-doped cobalt nine sulfide / foam nickel electrode material and a preparation method thereof

Abstract

The application provides a hollow thorn ball-like phosphorus-doped cobalt nonanethiolate / nickel foam electrode material and a preparation method thereof, and belongs to the technical field of supercapacitor electrode material preparation. The preparation method is as follows: taking nickel foam (NF) as a current collector, pretreating the NF, preparing a Co(OH)F-NF precursor through hydration, preparing Co9S8-NF through sulfuration, and finally preparing the hollow thorn ball-like P-Co9S8-NF electrode material through phosphorus doping. The preparation process is simple, easy to realize, and low in preparation cost, and can lay a technical support for the preparation of supercapacitor high-conductivity, high-structural-stability and high-energy-storage electrode materials, and has good application value and prospect in the field of supercapacitor electrode materials.

Description

Technical Field

[0001] This invention belongs to the field of supercapacitor electrode material preparation technology, specifically relating to a hollow spiky spherical phosphorus-doped cobalt octasulfide / nickel foam electrode material and its preparation method. Background Technology

[0002] Today, with increasingly severe energy shortages and environmental problems, there is an urgent need for high-performance energy storage and conversion devices. Among various storage and conversion devices, supercapacitors exhibit superior storage performance due to their unique electrochemical properties, such as rapid charge and discharge, long cycle life, and environmental friendliness. However, the low energy storage performance of supercapacitors has long limited their commercial application. Current research has found that the energy storage of supercapacitors depends on the electrode materials; therefore, designing and constructing appropriate supercapacitor electrode materials is an effective method to improve their storage performance.

[0003] Transition metal sulfides (Co9S8, MoS2, etc.) have attracted widespread attention as electrode materials for supercapacitors due to their high theoretical capacitance and abundant active sites. However, when used as electrode materials for supercapacitors, transition metal sulfides exhibit low electronic conductivity and poor structural stability. To improve the conductivity of transition metal sulfides, researchers have tried various methods, such as ion doping and composite carbon-based materials. Among these, ion-doped (P, N, B, etc.) transition metal sulfides exhibit high electronic conductivity, and using ion doping technology to improve the energy storage of transition metal sulfide electrode materials is an effective method. However, the poor structural stability of transition metal sulfides remains a key problem limiting the energy storage capacity of supercapacitors.

[0004] The structure of electrode materials is a key factor affecting the energy storage of supercapacitors. Currently, supercapacitor electrode materials include spherical, nanosheet, and rod-shaped structures. Hollow structures are considered highly promising electrode material structures due to their ability to mitigate volume and stress changes caused by electrochemical reactions. Furthermore, hollow structures can increase the contact area between the electrolyte and the electrode material, promoting electron transport during electrochemical reactions and facilitating energy storage and conversion in supercapacitors. However, in practice, the use of hollow structures as supercapacitor electrode materials is limited by stacking constraints, failing to fully utilize their large specific surface area and significantly weakening energy storage during electrochemical processes. Therefore, for transition metal sulfide electrode materials, how to improve electronic conductivity, ensure structural stability, and simultaneously increase their surface area is a pressing technical problem to be solved in this field. Summary of the Invention

[0005] The purpose of this invention is to provide a hollow, spiky, phosphorus-doped cobalt octasulfide / nickel foam electrode material and its preparation method. Using nickel foam (NF) as the current collector, a supercapacitor electrode material with high conductivity, high structural stability, high specific surface area and high energy density is prepared through a hydration-sulfidation-phosphorus doping treatment method.

[0006] This invention is achieved through the following technical solution:

[0007] A method for preparing a hollow, spiky, spherical phosphorus-doped cobalt octasulfide / nickel foam electrode material includes the following steps:

[0008] Step 1: Nickel foam pretreatment;

[0009] Cut the nickel foam, clean it to remove impurities, and dry it to obtain the nickel foam substrate, abbreviated as NF.

[0010] Step 2: Preparation of Co(OH)F-NF precursor by hydration

[0011] After stirring and dissolving the cobalt salt, fluorine source and promoter, the mixture was transferred to a reaction vessel and Co(OH)F was grown in situ on nickel foam through hydrothermal reaction. After the reaction was completed, the mixture was washed and dried to obtain the Co(OH)F-NF precursor.

[0012] Step 3: Preparation of Co9S8-NF by sulfidation

[0013] The sulfur source was dissolved by stirring and transferred to a reaction vessel. The Co(OH)F-NF precursor from step 2 was added. After the sulfidation reaction, the mixture was washed and dried to obtain Co9S8-NF.

[0014] Step 4: Phosphorus doping preparation of P-Co9S8-NF

[0015] In step 3, Co9S8-NF and a phosphorus source were co-calcined under an inert gas atmosphere to obtain P-Co9S8-NF.

[0016] Furthermore, the Co(OH)F-NF precursor has a spiky spherical structure, while Co9S8-NF and P-Co9S8-NF have hollow spiky spherical structures.

[0017] Furthermore, in step 1, the foamed nickel is cut into circular pieces, and then ultrasonically cleaned in acetone, anhydrous ethanol, and deionized water in sequence, and then dried in an oven.

[0018] Further, in step 2, the cobalt salt is Co(NO3)2·6H2O, the fluorine source is NH4F, the accelerator is CH4N2O, and the mass ratio of Co(NO3)2·6H2O, NH4F and CH4N2O is (2-4):1:(2-4);

[0019] In step 2, the hydrothermal reaction temperature is 110℃-130℃, and the reaction time is 6h-9h.

[0020] Furthermore, in step 3, the sulfur source is CH3CSNH2 or CH4N2S, and the solvent for dissolving the sulfur source is anhydrous ethanol or deionized water.

[0021] In step 3, the vulcanization reaction temperature is 105℃-135℃, and the reaction time is 4h-12h.

[0022] Furthermore, in step 4, the phosphorus source is NaH2PO2·H2O or (NH4)2HPO4;

[0023] In step 4, a tube furnace is used for calcination, with a heating rate of 2℃ / min-5℃ / min, heating to 300℃-350℃, and holding at that temperature for 0.5h-1.5h.

[0024] The present invention also provides a hollow spiky spherical phosphorus-doped cobalt octasulfide / nickel foam electrode material, which is prepared by the preparation method of the hollow spiky spherical phosphorus-doped cobalt octasulfide / nickel foam electrode material.

[0025] This invention provides an application of hollow, spiky, phosphorus-doped cobalt octasulfide / nickel foam electrode material in supercapacitors.

[0026] The application of the hollow spiky spherical phosphorus-doped cobalt octasulfide / nickel foam electrode material in supercapacitors was described. Electrochemical performance testing was performed using a three-electrode system: the working electrode was P-Co9S8-NF material, the counter electrode was a platinum sheet, the reference electrode was a calomel electrode, and the electrolyte was KOH.

[0027] Furthermore, the concentration of the electrolyte is 1 mol / L to 6 mol / L.

[0028] Advantages and effects of the present invention:

[0029] The hollow, spiky, spherical phosphorus-doped cobalt octasulfide / nickel foam electrode material prepared in this invention has promising application value and prospects in supercapacitor electrode materials. This invention uses NF as the current collector and employs a hydration-sulfidation-P doping method to prepare the hollow, spiky, spherical supercapacitor electrode material. Using NF as the current collector facilitates the dispersion of the electrode material, avoiding the problem of low ion transport efficiency caused by electrode material accumulation. The synthesis method of P-Co9S8-NF is simple and easy to implement. The hollow structure formed by P-Co9S8-NF can alleviate the volume and stress changes caused by electrochemical reactions, increase the contact area between the electrolyte and the electrode material, and improve the stability of the electrode material. The introduction of phosphorus improves the conductivity of the electrode material, facilitating electron transport. The effective synergy of the P-Co9S8-NF structure can effectively improve the energy storage performance of the supercapacitor. The preparation process of this P-doped hollow, spiky, spherical Co9S8 supercapacitor electrode material is simple, easy to implement, and low in cost, providing technical support for the preparation of high-conductivity, high-structural-stability, and high-energy-storage electrode materials for supercapacitors. Attached Figure Description

[0030] Figure 1 These are scanning electron microscope (SEM) images of the Co(OH)F-NF, Co9S8-NF, and P-Co9S8-NF materials prepared in Example 1, where a is the SEM image of Co(OH)F-NF, b is the SEM image of Co9S8-NF, c is a magnified SEM image of P-Co9S8-NF, and d is the SEM image of P-Co9S8-NF.

[0031] Figure 2 This is a transmission electron microscope (TEM) image of the P-Co9S8-NF material prepared in Example 1;

[0032] Figure 3 These are X-ray diffraction (XRD) patterns of the Co9S8-NF and P-Co9S8-NF materials prepared in Example 1;

[0033] Figure 4 The cyclic voltammetry (CV) curves of Co9S8-NF and P-Co9S8-NF at a scan rate of 3 mV / s are shown in Application Example 1.

[0034] Figure 5 In Example 1, Co9S8-NF and P-Co9S8-NF are used at a current density of 3 mA / cm². 2 The constant current charge-discharge (GCD) curves;

[0035] Figure 6 The cyclic voltammetry (CV) curves of P-Co9S8-NF in Application Example 1 at scan rates of 1 mV / s, 3 mV / s, and 5 mV / s are shown.

[0036] Figure 7 The P-Co9S8-NF electrode material in Example 1 is used at a current density of 3 mA / cm². 2 5mA / cm 2 and 10mA / cm 2 Constant current charge-discharge (GCD) curves under these conditions;

[0037] Figure 8 This is a scanning electron microscope (SEM) image of the P-Co9S8-NF material prepared in Example 2;

[0038] Figure 9 This is a scanning electron microscope (SEM) image of the P-Co9S8-NF material prepared in Example 3;

[0039] Figure 10 This is a scanning electron microscope (SEM) image of the P-Co9S8-NF material prepared in Example 4;

[0040] Figure 11 This is a scanning electron microscope (SEM) image of the P-Co9S8-NF material prepared in Example 5;

[0041] Figure 12 This is a scanning electron microscope (SEM) image of the P-Co9S8-NF material prepared in Example 6;

[0042] Figure 13 This is a scanning electron microscope (SEM) image of the P-Co9S8-NF material prepared in Example 7;

[0043] Figure 14 This is a scanning electron microscope (SEM) image of the P-Co9S8-NF material prepared in Example 8. Detailed Implementation

[0044] The present invention will now be described in detail with reference to the embodiments.

[0045] Example 1

[0046] A method for preparing a hollow, spiky, spherical phosphorus-doped cobalt octasulfide / nickel foam electrode material includes the following steps:

[0047] Step 1: NF Preprocessing

[0048] NF was cut into 0.5cm round pieces and then placed in 20mL of acetone, anhydrous ethanol and deionized water for ultrasonic treatment to remove impurities on the surface of NF. The pieces were then dried in an oven at 60℃ for 6h.

[0049] Step 2: Preparation of Co(OH)F-NF precursor by hydration

[0050] Co(NO3)2·6H2O (0.3g), NH4F (0.15g), and CH4N2O (0.30g) were dissolved in 20mL of deionized water under stirring at room temperature, resulting in a pink solution. The solution was poured into a 100mL reaction vessel, and NF was placed at the bottom of the vessel. The vessel was then placed in an oven at 120℃ for 9 hours for hydrothermal reaction. After the temperature of the reaction vessel dropped to room temperature, NF was removed, washed several times with deionized water, and dried in an oven at 60℃ for 6 hours to obtain the spiky Co(OH)F-NF precursor.

[0051] Step 3: Preparation of Co9S8-NF by sulfidation

[0052] Measure 30 mL of anhydrous ethanol, dissolve CH3CSNH2 (0.030 g) in anhydrous ethanol at room temperature, and stir until dissolved; then, transfer the above solution into a 100 mL reaction vessel, and put the Co(OH)F-NF precursor prepared in step 2 into the reaction vessel for sulfidation reaction, keep it in an oven at 120℃ for 8 h, cool to room temperature, wash several times with anhydrous ethanol, and dry in an oven at 60℃ for 6 h to obtain black hollow spiky spherical Co9S8-NF.

[0053] Step 4: P-doping preparation of P-Co9S8-NF

[0054] 0.02 g of NaH2PO2·H2O and one piece of Co9S8-NF prepared in step 3 were placed in a ceramic boat. NaH2PO2·H2O was placed upstream of the tube furnace (i.e., in the direction of Ar flow into the tube furnace), and Co9S8-NF was placed downstream (i.e., in the direction of Ar flow out of the tube furnace). Under Ar protection, the temperature was raised to 300°C at a rate of 2°C / min and held for 1 h to obtain the target product, hollow spiky spherical P-Co9S8-NF.

[0055] Example 2

[0056] A method for preparing a hollow, spiky, spherical phosphorus-doped cobalt octasulfide / nickel foam electrode material includes the following steps:

[0057] Step 1: NF Preprocessing

[0058] NF was cut into 0.5cm round pieces and then placed in 20mL of acetone, anhydrous ethanol and deionized water for ultrasonic treatment to remove impurities on the surface of NF. The pieces were then dried in an oven at 60℃ for 6h.

[0059] Step 2: Preparation of Co(OH)F-NF precursor by hydration

[0060] Co(NO3)2·6H2O (0.6g), NH4F (0.15g), and CH4N2O (0.6g) were dissolved in 20mL of deionized water under stirring at room temperature, and the solution turned pink. The solution was poured into a 100mL reaction vessel, and NF was placed at the bottom of the reaction vessel. The reaction was carried out at 130℃ for 6h for hydrothermal reaction. The mixture was washed several times with deionized water and dried in an oven at 60℃ for 6h to obtain the precursor spiky Co(OH)F-NF precursor.

[0061] Step 3: Preparation of Co9S8-NF by sulfidation

[0062] Measure 30 mL of anhydrous ethanol, dissolve CH3CSNH2 (0.030 g) in anhydrous ethanol at room temperature, and stir until dissolved; then, transfer the above solution into a 100 mL reaction vessel, and put the Co(OH)F-NF precursor prepared in step 2 into the reaction vessel for sulfidation reaction, keep it in an oven at 120℃ for 8 h, cool to room temperature, wash several times with anhydrous ethanol, and dry in an oven at 60℃ for 6 h to obtain black hollow spiky spherical Co9S8-NF.

[0063] Step 4: P-doping preparation of P-Co9S8-NF

[0064] 0.02 g of NaH2PO2·H2O and one piece of Co9S8-NF prepared in step 3 were placed in a ceramic boat. NaH2PO2·H2O was placed upstream of the tube furnace (i.e., in the direction of Ar flow into the tube furnace), and Co9S8-NF was placed downstream (i.e., in the direction of Ar flow out of the tube furnace). Under Ar protection, the temperature was raised to 300°C at a rate of 3°C / min and held for 1.5 h to obtain the target product, hollow spiky spherical P-Co9S8-NF.

[0065] Example 3

[0066] A method for preparing a hollow, spiky, spherical phosphorus-doped cobalt octasulfide / nickel foam electrode material includes the following steps:

[0067] Step 1: NF Preprocessing

[0068] NF was cut into 0.5cm round pieces and then placed in 20mL of acetone, anhydrous ethanol and deionized water for ultrasonic treatment to remove impurities on the surface of NF. The pieces were then dried in an oven at 60℃ for 6h.

[0069] Step 2: Preparation of Co(OH)F-NF precursor by hydration

[0070] Co(NO3)2·6H2O (0.45g), NH4F (0.15g), and CH4N2O (0.45g) were dissolved in 20mL of deionized water under stirring at room temperature, and the solution turned pink. The solution was poured into a 100mL reaction vessel, and NF was placed at the bottom of the reaction vessel. The reaction was carried out at 125℃ for 7h for hydrothermal reaction. The mixture was washed several times with deionized water and dried in an oven at 60℃ for 6h to obtain the precursor spiky Co(OH)F-NF precursor.

[0071] Step 3: Preparation of Co9S8-NF by sulfidation

[0072] Measure 30 mL of anhydrous ethanol, dissolve CH3CSNH2 (0.030 g) in anhydrous ethanol at room temperature, and stir until dissolved; then, transfer the above solution into a 100 mL reaction vessel, and put the Co(OH)F-NF precursor prepared in step 2 into the reaction vessel for sulfidation reaction, keep it in an oven at 105 °C for 12 h, cool to room temperature, wash several times with anhydrous ethanol, and dry in an oven at 60 °C for 6 h to obtain black hollow spiky spherical Co9S8-NF.

[0073] Step 4: P-doping preparation of P-Co9S8-NF

[0074] 0.02 g of NaH2PO2·H2O and one piece of Co9S8-NF prepared in step 3 were placed in a ceramic boat. NaH2PO2·H2O was placed upstream of the tube furnace (i.e., in the direction of Ar flow into the tube furnace), and Co9S8-NF was placed downstream (i.e., in the direction of Ar flow out of the tube furnace). Under Ar protection, the temperature was raised to 310 °C at a rate of 2 °C / min and held for 1.3 h to obtain the target product, hollow spiky spherical P-Co9S8-NF.

[0075] Example 4

[0076] A method for preparing a hollow, spiky, spherical phosphorus-doped cobalt octasulfide / nickel foam electrode material includes the following steps:

[0077] Step 1: NF Preprocessing

[0078] NF was cut into 0.5cm round pieces and then placed in 20mL of acetone, anhydrous ethanol and deionized water for ultrasonic treatment to remove impurities on the surface of NF. The pieces were then dried in an oven at 60℃ for 6h.

[0079] Step 2: Preparation of Co(OH)F-NF precursor by hydration

[0080] Co(NO3)2·6H2O (0.3g), NH4F (0.15g), and CH4N2O (0.3g) were dissolved in 20mL of deionized water under stirring at room temperature, and the solution turned pink. The solution was poured into a 100mL reaction vessel, and NF was placed at the bottom of the reaction vessel. The hydrothermal reaction was carried out at 120℃ for 8h. The mixture was washed several times with deionized water and dried in an oven at 60℃ for 6h to obtain the precursor spiky Co(OH)F-NF.

[0081] Step 3: Preparation of Co9S8-NF by sulfidation

[0082] Measure 30 mL of anhydrous ethanol, dissolve CH3CSNH2 (0.030 g) in anhydrous ethanol at room temperature, and stir until dissolved; then, transfer the above solution into a 100 mL reaction vessel, and put the Co(OH)F-NF precursor prepared in step 2 into the reaction vessel for sulfidation reaction, keep it in an oven at 110 °C for 10 h, cool to room temperature, wash several times with anhydrous ethanol, and dry in an oven at 60 °C for 6 h to obtain black hollow spiky spherical Co9S8-NF.

[0083] Step 4: P-doping preparation of P-Co9S8-NF

[0084] 0.02 g of NaH2PO2·H2O and one piece of Co9S8-NF prepared in step 3 were placed in a ceramic boat. NaH2PO2·H2O was placed upstream of the tube furnace (i.e., in the direction of Ar flow into the tube furnace), and Co9S8-NF was placed downstream (i.e., in the direction of Ar flow out of the tube furnace). Under Ar protection, the temperature was raised to 320°C at a rate of 4°C / min and held for 1.1 h to obtain the target product, hollow spiky spherical P-Co9S8-NF.

[0085] Example 5

[0086] A method for preparing a hollow, spiky, spherical phosphorus-doped cobalt octasulfide / nickel foam electrode material includes the following steps:

[0087] Step 1: NF Preprocessing

[0088] NF was cut into 0.5cm round pieces and then placed in 20mL of acetone, anhydrous ethanol and deionized water for ultrasonic treatment to remove impurities on the surface of NF. The pieces were then dried in an oven at 60℃ for 6h.

[0089] Step 2: Preparation of Co(OH)F-NF precursor by hydration

[0090] Co(NO3)2·6H2O (0.3g), NH4F (0.15g), and CH4N2O (0.3g) were dissolved in 20mL of deionized water under stirring at room temperature, and the solution turned pink. The solution was poured into a 100mL reaction vessel, and NF was placed at the bottom of the reaction vessel. The reaction was carried out at 115℃ for 9h for hydrothermal reaction. The mixture was washed several times with deionized water and dried in an oven at 60℃ for 6h to obtain the precursor spiky Co(OH)F-NF precursor.

[0091] Step 3: Preparation of Co9S8-NF by sulfidation

[0092] Measure 30 mL of anhydrous ethanol, dissolve CH3CSNH2 (0.030 g) in anhydrous ethanol at room temperature, and stir until dissolved; then, transfer the above solution into a 100 mL reaction vessel, and put the Co(OH)F-NF precursor prepared in step 2 into the reaction vessel for sulfidation reaction, keep it in an oven at 115 °C for 8 h, cool to room temperature, wash several times with anhydrous ethanol, and dry in an oven at 60 °C for 6 h to obtain black hollow spiky spherical Co9S8-NF.

[0093] Step 4: P-doping preparation of P-Co9S8-NF

[0094] 0.02 g of NaH2PO2·H2O and one piece of Co9S8-NF prepared in step 3 were placed in a ceramic boat. NaH2PO2·H2O was placed upstream of the tube furnace (i.e., in the direction of Ar flow into the tube furnace), and Co9S8-NF was placed downstream (i.e., in the direction of Ar flow out of the tube furnace). Under Ar protection, the temperature was raised to 350°C at a rate of 5°C / min and held for 0.5 h to obtain the target product, hollow spiky spherical P-Co9S8-NF.

[0095] Example 6

[0096] A method for preparing a hollow, spiky, spherical phosphorus-doped cobalt octasulfide / nickel foam electrode material includes the following steps:

[0097] Step 1: NF Preprocessing

[0098] NF was cut into 0.5cm round pieces and then placed in 20mL of acetone, anhydrous ethanol and deionized water for ultrasonic treatment to remove impurities on the surface of NF. The pieces were then dried in an oven at 60℃ for 6h.

[0099] Step 2: Preparation of Co(OH)F-NF precursor by hydration

[0100] Co(NO3)2·6H2O (0.3g), NH4F (0.15g), and CH4N2O (0.3g) were dissolved in 20mL of deionized water under stirring at room temperature, and the solution turned pink. The solution was poured into a 100mL reaction vessel, and NF was placed at the bottom of the reaction vessel. The reaction was carried out at 120℃ for 9h for hydrothermal reaction. The mixture was washed several times with deionized water and dried in an oven at 60℃ for 6h to obtain the precursor spiky Co(OH)F-NF precursor.

[0101] Step 3: Preparation of Co9S8-NF by sulfidation

[0102] Take 30 mL of deionized water and dissolve CH4N2S (0.030 g) in the deionized water at room temperature, stirring until dissolved; then, transfer the above solution into a 100 mL reaction vessel, and put the Co(OH)F-NF precursor prepared in step 2 into the reaction vessel for sulfidation reaction, keep it in an oven at 125℃ for 6 h, cool to room temperature, wash several times with anhydrous ethanol, and dry in an oven at 60℃ for 6 h to obtain black hollow spiky spherical Co9S8-NF.

[0103] Step 4: P-doping preparation of P-Co9S8-NF

[0104] 0.02 g of NaH2PO2·H2O and one piece of Co9S8-NF prepared in step 3 were placed in a ceramic boat. NaH2PO2·H2O was placed upstream of the tube furnace (i.e., in the direction of Ar flow into the tube furnace), and Co9S8-NF was placed downstream (i.e., in the direction of Ar flow out of the tube furnace). Under Ar protection, the temperature was raised to 330°C at a rate of 3°C / min and held for 0.9 h to obtain the target product, hollow spiky spherical P-Co9S8-NF.

[0105] Example 7

[0106] A method for preparing a hollow, spiky, spherical phosphorus-doped cobalt octasulfide / nickel foam electrode material includes the following steps:

[0107] Step 1: NF Preprocessing

[0108] NF was cut into 0.5cm round pieces and then placed in 20mL of acetone, anhydrous ethanol and deionized water for ultrasonic treatment to remove impurities on the surface of NF. The pieces were then dried in an oven at 60℃ for 6h.

[0109] Step 2: Preparation of Co(OH)F-NF precursor by hydration

[0110] Co(NO3)2·6H2O (0.3g), NH4F (0.15g), and CH4N2O (0.3g) were dissolved in 20mL of deionized water under stirring at room temperature, and the solution turned pink. The solution was poured into a 100mL reaction vessel, and NF was placed at the bottom of the reaction vessel. The reaction was carried out at 110℃ for 9h for hydrothermal reaction. The mixture was washed several times with deionized water and dried in an oven at 60℃ for 6h to obtain the precursor spiky Co(OH)F-NF precursor.

[0111] Step 3: Preparation of Co9S8-NF by sulfidation

[0112] Measure 30 mL of anhydrous ethanol, dissolve CH3CSNH2 (0.030 g) in anhydrous ethanol at room temperature, and stir until dissolved; then, transfer the above solution into a 100 mL reaction vessel, and put the Co(OH)F-NF precursor prepared in step 2 into the reaction vessel for sulfidation reaction, keep it in an oven at 130℃ for 5 h, cool to room temperature, wash several times with anhydrous ethanol, and dry in an oven at 60℃ for 6 h to obtain black hollow spiky spherical Co9S8-NF.

[0113] Step 4: P-doping preparation of P-Co9S8-NF

[0114] (NH4)2HPO4 (0.02 g) and one piece of Co9S8-NF prepared in step 3 were placed in a ceramic boat. (NH4)2HPO4 was placed upstream of the tube furnace (i.e., in the direction of Ar flow into the tube furnace), and Co9S8-NF was placed downstream (i.e., in the direction of Ar flow out of the tube furnace). Under Ar protection, the temperature was raised to 340°C at a rate of 4°C / min and held for 0.7 h to obtain the target product, hollow spiky spherical P-Co9S8-NF.

[0115] Example 8

[0116] A method for preparing a hollow, spiky, spherical phosphorus-doped cobalt octasulfide / nickel foam electrode material includes the following steps:

[0117] Step 1: NF Preprocessing

[0118] NF was cut into 0.5cm round pieces and then placed in 20mL of acetone, anhydrous ethanol and deionized water for ultrasonic treatment to remove impurities on the surface of NF. The pieces were then dried in an oven at 60℃ for 6h.

[0119] Step 2: Preparation of Co(OH)F-NF precursor by hydration

[0120] Co(NO3)2·6H2O (0.3g), NH4F (0.15g), and CH4N2O (0.3g) were dissolved in 20mL of deionized water under stirring at room temperature, and the solution turned pink. The solution was poured into a 100mL reaction vessel, and NF was placed at the bottom of the reaction vessel. The reaction was carried out at 120℃ for 9h for hydrothermal reaction. The mixture was washed several times with deionized water and dried in an oven at 60℃ for 6h to obtain the precursor spiky Co(OH)F-NF precursor.

[0121] Step 3: Preparation of Co9S8-NF by sulfidation

[0122] Measure 30 mL of anhydrous ethanol, dissolve CH3CSNH2 (0.030 g) in anhydrous ethanol at room temperature, and stir until dissolved; then, transfer the above solution into a 100 mL reaction vessel, and put the Co(OH)F-NF precursor prepared in step 2 into the reaction vessel for sulfidation reaction, keep it in an oven at 135℃ for 4 h, cool to room temperature, wash several times with anhydrous ethanol, and dry in an oven at 60℃ for 6 h to obtain black hollow spiky spherical Co9S8-NF.

[0123] Step 4: P-doping preparation of P-Co9S8-NF

[0124] 0.02 g of NaH2PO2·H2O and one piece of Co9S8-NF prepared in step 3 were placed in a ceramic boat. NaH2PO2·H2O was placed upstream of the tube furnace (i.e., in the direction of Ar flow into the tube furnace), and Co9S8-NF was placed downstream (i.e., in the direction of Ar flow out of the tube furnace). Under Ar protection, the temperature was raised to 350°C at a rate of 5°C / min and held for 1 h to obtain the target product, hollow spiky spherical P-Co9S8-NF.

[0125] Application Example 1

[0126] The P-Co9S8-NF prepared in Example 1 was used as an electrode material in a supercapacitor.

[0127] Electrochemical performance testing was performed using a three-electrode system: the working electrode was P-Co9S8-NF material, the counter electrode was a platinum sheet, the reference electrode was a calomel electrode, and the electrolyte was a 6 mol / L KOH solution.

[0128] Property Characterization

[0129] Figure 1 The image shows the scanning electron microscope (SEM) results of the Co(OH)F-NF, Co9S8-NF, and P-Co9S8-NF materials prepared by the preparation method in Example 1 of this invention. Figure 1 In the middle a, Co(OH)F-NF has a spiky spherical structure, about 15 μm in size, and grows uniformly; Figure 1b is Co9S8-NF obtained after sulfidation treatment. The spiky structure remains intact and is not damaged by the sulfidation treatment, indicating that the spiky structure has excellent stability. Figure 1 In the middle c, there is a magnified view of P-Co9S8-NF obtained after phosphorus doping treatment. As can be seen from the figure, P-Co9S8-NF is uniformly dispersed and grows stably on NF, without accumulation or phosphorus doping treatment detachment, indicating that the material has excellent dispersibility and stability. Figure 1 Figure d is a scanning electron microscope image of P-Co9S8-NF. Compared with Figures a and b, P-Co9S8-NF still exhibits a spiky structure, with no change in size or obvious microstructural changes, further demonstrating that the spiky structure has excellent structural stability.

[0130] Figure 2 The figure shows the transmission electron microscopy (TEM) results of P-Co9S8-NF material in the preparation method of hollow spiky spherical phosphorus-doped cobalt octasulfide / nickel foam electrode material in Example 1 of this invention. As can be seen from the figure, the P-Co9S8-NF material has a hollow structure with a wall thickness of about 3.60 nm. The good hollow structure can provide a large specific surface area for the material, which can alleviate stress and volume changes during electrochemical reactions, facilitate ion transport, and lay the foundation for high energy storage in supercapacitors.

[0131] Figure 3 The figure shows the XRD patterns of Co9S8-NF and P-Co9S8-NF materials in the preparation method of hollow spiky spherical phosphorus-doped cobalt octasulfide / nickel foam electrode material of Embodiment 1 of the present invention. As can be seen from the figure, the three peaks at 2θ at 44.49°, 51.84° and 76.37° are characteristic peaks of NF; the characteristic peak of Co9S8 coincides with the characteristic peak of NF at 51.84°, and there is a characteristic peak of Co9S8 at 26.04°. Because the diffraction peak intensity of NF is stronger, the diffraction peak intensity of Co9S8 is weaker; after phosphorus doping, the diffraction peak of Co9S8 at 26.04° shifts to the negative direction and the diffraction peak intensity decreases, indicating that phosphorus doping has a certain impact on the diffraction peak of Co9S8 and reduces its crystallinity. The above shows that Co9S8 was successfully prepared and P element was successfully doped into Co9S8 material.

[0132] Figure 4 The figure shows the CV curves of Co9S8-NF and P-Co9S8-NF as electrode materials in Application Example 1 of this invention at a scan rate of 3mV / s. As can be seen from the figure, both of them have a pair of redox peaks as electrode materials, indicating that they have pseudocapacitive properties. In addition, the area of ​​the CV curve of P-Co9S8-NF as electrode material is significantly larger than that of Co9S8-NF, indicating that the doping of P element effectively improves the storage performance of the electrode material.

[0133] Figure 5 The image shows Co9S8-NF and P-Co9S8-NF used as electrode materials in Application Example 1 of this invention at a current density of 3 mA / cm². 2 The GCD curves at 3 mA / cm² are shown in the figure. As can be seen from the figure, both electrode materials exhibit a pair of charge-discharge plateaus, further confirming their pseudocapacitive properties. Furthermore, P-Co9S8-NF demonstrates a longer discharge time, indicating that this electrode material has better electrochemical performance. 2 At that time, the areal capacitance of Co9S8-NF was 11.78 F / cm². 2 The areal capacitance of P-Co9S8-NF reached 15.47 F / cm². 2 This indicates that doping with P element effectively improves the conductivity of the electrode material and promotes its energy storage.

[0134] Figure 6 The figure shows the CV curves of the P-Co9S8-NF electrode material in Application Example 1 of the present invention at scan rates of 1 mV / s, 3 mV / s and 5 mV / s. As the scan rate increases, the area of ​​the CV curve of the P-Co9S8-NF electrode material increases, but it still shows a very obvious redox peak, indicating that the electrode material has good rate performance.

[0135] Figure 7 The example shown is an application of the present invention, in Example 1, where the P-Co9S8-NF electrode material operates at 3 mA / cm². 2 5mA / cm 2 and 10mA / cm 2 GCD test results at current density; the figure shows that the electrode material exhibits good performance even at a current density of 10 mA / cm². 2 At that time, the redox peaks of P-Co9S8-NF remained very obvious, indicating that it has very good electrochemical reversibility; based on GCD test results, at a current density of 3 mA / cm², the redox peaks of P-Co9S8-NF were still ... 2 5mA / cm 2 and 10mA / cm 2 At that time, its areal capacitance was 15.47 F / cm². 2 15.06F / cm 2 and 14.65F / cm 2 Even at a high current density of 10 mA / cm 2 Even under these conditions, P-Co9S8-NF still exhibits good capacitance performance, indicating that this electrode material has excellent energy storage characteristics.

[0136] Figures 8-14The images shown correspond to the scanning electron microscopy test results of the P-Co9S8-NF materials prepared in Examples 2-8 of this invention, and all exhibit a spiky spherical structure.

Claims

1. A preparation method of a hollow cobaltosic sulfate phosphorus-doped electrode material, characterized in that, Includes the following steps: Step 1: Nickel foam pretreatment; Cut the nickel foam, clean it to remove impurities, and dry it to obtain the nickel foam substrate, abbreviated as NF. Step 2: Preparation of Co(OH)F-NF precursor by hydration Cobalt salt Co(NO3)2·6H2O, fluorine source NH4F and promoter CH4N2O were dissolved by stirring in a mass ratio of (2-4):1:(2-4), and then transferred to a reaction vessel. The mixture was subjected to hydrothermal reaction at 110℃-130℃ for 6-9 hours to grow Co(OH)F in situ on nickel foam. After the reaction was completed, the mixture was washed and dried to obtain the Co(OH)F-NF precursor. Step 3: Preparation of Co9S8-NF by sulfidation Stir and dissolve the sulfur source H3CSNH2 or CH4N2S. The solvent for dissolving the sulfur source is anhydrous ethanol or deionized water. Transfer the solution into a reaction vessel and add the Co(OH)F-NF precursor from step 2. Perform a sulfurization reaction at 105℃-135℃ for 4-12 hours. Then wash and dry to obtain Co9S8-NF. Step 4: Phosphorus doping preparation of P-Co9S8-NF Co9S8-NF prepared in step 3 was calcined with a phosphorus source NaH2PO2·H2O or (NH 4)2 HPO4 under inert gas protection, and heated to 300-350℃ at a heating rate of 2-5℃ / min, and kept for 0.5-1.5h to obtain P-Co9S8-NF.

2. The method for preparing a hollow, spiky, spherical phosphorus-doped cobalt octasulfide / nickel foam electrode material according to claim 1, characterized in that, The Co(OH)F-NF precursor has a spiky spherical structure, while Co9S8-NF and P-Co9S8-NF have a hollow spiky spherical structure.

3. The method for preparing a hollow, spiky, spherical phosphorus-doped cobalt octasulfide / nickel foam electrode material according to claim 1, characterized in that, In step 1, the nickel foam is cut into circular pieces, and then ultrasonically cleaned in acetone, anhydrous ethanol, and deionized water in sequence, and then dried in an oven.

4. A hollow, spiky, spherical phosphorus-doped cobalt octasulfide / nickel foam electrode material, characterized in that, The hollow spiky spherical phosphorus-doped cobalt octasulfide / nickel foam electrode material is prepared using the preparation method described in any one of claims 1-3.

5. The application of the hollow spiky spherical phosphorus-doped cobalt octasulfide / nickel foam electrode material as described in claim 4 in supercapacitors.

6. The application of the hollow, spiky, spherical phosphorus-doped cobalt octasulfide / nickel foam electrode material according to claim 5 in a supercapacitor, characterized in that, Electrochemical performance testing employed a three-electrode system: the working electrode was P-Co9S8-NF material, the counter electrode was a platinum sheet, the reference electrode was a calomel electrode, and the electrolyte was KOH.

7. The application of the hollow, spiky, spherical phosphorus-doped cobalt octasulfide / nickel foam electrode material according to claim 6 in a supercapacitor, characterized in that, The concentration of the electrolyte is 1 mol / L to 6 mol / L.

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