Co11 (HPO3) 8 (OH) 6 / Co9S8 nanotube composite electrode material and preparation method thereof

Abstract

The invention discloses a Co11 (HPO3) 8 (OH) 6 / Co9S8 nanotube composite electrode material and a preparation method thereof, and belongs to the technical field of functional material preparation. According to the method, cobalt chloride and sodium pyrophosphate are used as raw materials, water is used as a solvent, a Co11 (HPO3) 8 (OH) 6 nanowire is prepared through a hydrothermal method, and after the Co11 (HPO3) 8 (OH) 6 / Co9S8 nanotube is prepared after the Co11 (HPO3) 8 (OH) 6 / Co9S8 nanowire is vulcanized. The Co11 (HPO3) 8 (OH) 6 / Co9S8 nanotube is applied to a supercapacitor as an electrode material, and has relatively good electrochemical energy storage performance. When the current density is 4.0 A g <-1 >, 6.0 A g <-1 >, 10 A g <-1 >, 15 A g <-1 > and 20 A g <-1 >, the capacitance is 1218 F g <-1 >, 1098.3 F g <-1 >, 1022 F g <-1 >, 918.8 F g And under 10A g <-1 >, after 10000 charge-discharge cycles, the capacitance of the material can still reach 920F g <-1 >. The method is easy to operate and implement, low in cost, high in yield and good in reproducibility, and has a good application prospect in supercapacitor devices.

Description

Technical Field

[0001] The present invention relates to a Co 11 (HPO 3 ) 8 (OH) 6 / Co 9 S 8 The invention relates to a nanotube composite electrode material and a preparation method thereof, belonging to the technical field of functional material preparation. Background Art

[0002] Supercapacitors have the advantages of fast charging and discharging, high power density, and long cycle life, and are energy storage devices with great application prospects. Electrode materials, as an important component of supercapacitors, directly affect the performance of supercapacitors. Nanomaterials science, especially nanomaterials with novel morphology and structure, has become one of the current research hotspots. By regulating the morphology and structure of functional nanomaterials, their physical and chemical properties can be further adjusted, thereby improving their application performance. Therefore, the development of electrode materials with novel morphology and structure is of great research significance.

[0003] One-dimensional hollow nanoelectrode materials have excellent electrochemical properties due to their unique structural characteristics. In electrochemical energy storage, the rough surface of the hollow structure can expose more effective electrochemical active sites and promote the electrochemical reaction rate, while the one-dimensional overall structure is conducive to the rapid transfer and supply of electrons in the electrochemical reaction. Composite materials can give full play to the advantages of each component and make up for the shortcomings of single-component electrode materials in applications. Therefore, the design and construction of composite materials with one-dimensional hollow structures is of great research significance.

[0004] The template-assisted method can realize the controllable preparation of one-dimensional hollow micro-nanostructures. 11 (HPO 3 ) 8 (OH) 6 Nanowires were used as templates to prepare Co with excellent electrochemical performance by sulfurization method. 11 (HPO 3 ) 8 (OH) 6 / Co 9 S 8 There is no relevant literature report on nanotube composite electrode materials. Summary of the invention

[0005] Based on the current technical status, the purpose of the present invention is to provide a Co 11 (HPO 3 ) 8 (OH) 6 / Co 9 S 8Preparation method of nanotube composite electrode material; Another purpose is to provide Co with good electrochemical energy storage performance 11 (HPO 3 ) 8 (OH) 6 / Co 9 S 8 Nanotube composite electrode materials.

[0006] To achieve the purpose of the present invention, in the technical scheme of the present invention, cobalt salt and pyrophosphate are added to a water solvent, stirred and mixed, and the reaction solution is transferred to a reactor, and subjected to a hydrothermal reaction to obtain Co 11 (HPO 3 ) 8 (OH) 6 Nanowires can be prepared by sulfurizing them. 11 (HPO 3 ) 8 (OH) 6 / Co 9 S 8 Nanotube composite electrode materials.

[0007] The specific steps are as follows:

[0008] 1) Co 11 (HPO 3 ) 8 (OH) 6 Preparation of nanowires: Add cobalt salt and pyrophosphate to water solvent, stir and mix to prepare a reaction solution; transfer the reaction solution to a reactor, heat the reaction (180-220°C), and after the reaction is completed, naturally cool to room temperature; centrifuge the product, wash, and dry to obtain Co 11 (HPO 3 ) 8 (OH) 6 Nanowires. The concentration of cobalt salt in the reaction solution is 0.005-0.1 mol·L -1 The concentration of pyrophosphate is 0.005~0.1mol·L -1 , the molar ratio between the cobalt salt and the pyrophosphate is 1:1.

[0009] 2) Co 11 (HPO 3 ) 8 (OH) 6 / Co 9 S 8 Preparation of nanotubes: Co prepared in step (1) 11 (HPO 3 ) 8 (OH) 6The nanowires are subjected to a sulfidation reaction in a sulfide salt solution (70-100°C) to obtain Co 11 (HPO 3 ) 8 (OH) 6 / Co 9 S 8 Nanotubes. The concentration of sulfide salt in the reaction solution is 0.02-0.1 mol·L -1 ,Co 11 (HPO 3 ) 8 (OH) 6 The concentration is 3.6×10 -4 ~3.6×10 -3 mol·L -1 ,Co 11 (HPO 3 ) 8 (OH) 6 The molar ratio between sulfuric acid and sulfide salt is 0.018:1 to 0.036:1.

[0010] In the method of the present invention, the cobalt salt is preferably cobalt chloride hexahydrate, the pyrophosphate is preferably sodium pyrophosphate, and the sulfide salt is preferably sodium sulfide.

[0011] The advantages and innovations of the present invention are as follows:

[0012] 1. Co was synthesized by a simple hydrothermal method 11 (HPO 3 ) 8 (OH) 6 Nanowires, the compound can be derived from Co through sulfurization reaction 11 (HPO 3 ) 8 (OH) 6 / Co 9 S 8 Nanotubes.

[0013] 2. Co 11 (HPO 3 ) 8 (OH) 6 / Co 9 S 8 Nanotubes are used in supercapacitor devices with current densities of 4.0, 6.0, 10, 15 and 20 A g -1 When the capacitance is 1218, 1098.3, 1022, 918.8 and 805 F g -1 , at 10A g -1 After 10,000 charge and discharge cycles, its capacity can still reach 920F g -1 . Indicates that Co11 (HPO 3 ) 8 (OH) 6 / Co 9 S 8 Nanotubes have great application prospects in supercapacitor devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 Co obtained in Example 1 of the present invention 11 (HPO 3 ) 8 (OH) 6 / Co 9 S 8 Schematic diagram of the synthesis of nanotubes.

[0015] Figure 2 Co obtained in Example 1 of the present invention 11 (HPO 3 ) 8 (OH) 6 SEM images (ac) and TEM images (d) of nanowires, Co 11 (HPO 3 ) 8 (OH) 6 / Co 9 S 8 SEM (eg) and TEM (h) images of nanotubes, Co 11 (HPO 3 ) 8 (OH) 6 / Co 9 S 8 High-resolution transmission electron microscopy images and electron diffraction patterns of nanotubes (i), Co 11 (HPO 3 ) 8 (OH) 6 / Co 9 S 8 Dark field scanning transmission electron microscopy image of nanotubes (j)

[0016] And the composition imaging diagrams of Co, P, O and S elements, and the overlapping composition imaging diagrams of the four elements Co, P, O and S.

[0017] Figure 3 Co obtained in Example 1 of the present invention 11 (HPO 3 ) 8 (OH) 6 / Co 9 S 8 X-ray powder diffraction pattern of nanotubes.

[0018] Figure 4 Co obtained in Example 1 of the present invention 11 (HPO 3 ) 8 (OH) 6 / Co 9 S 8 Nitrogen adsorption-desorption curves of nanotubes.

[0019] Figure 5 Co obtained in Example 1 of the present invention 11 (HPO 3 ) 8 (OH) 6 / Co 9 S 8 Electrochemical performance of nanotubes: (a) Cyclic voltammetry curves at different scan rates, (b) Charge-discharge curves at different current densities, (c) Capacitance at different current densities, (d) Capacitance at 10A g -1 The stability curve after 10,000 cycles of charge and discharge. DETAILED DESCRIPTION

[0020] In order to better illustrate the present invention, Figure 1 Co 11 (HPO 3 ) 8 (OH) 6 / Co 9 S 8 The synthesis schematic diagram of nanotubes is shown below with examples. The following examples are provided to further illustrate the present invention but are not intended to limit the scope of the present invention.

[0021] Example 1

[0022] ① Add 1.0mmol of cobalt chloride hexahydrate and 1.0mmol of sodium pyrophosphate into 20mL of water, stir and mix, transfer the reaction solution into a reactor, react at 220℃ for 6 days, and after the reaction is completed, cool naturally to room temperature, centrifuge the product, wash with water several times and dry to obtain Co 11 (HPO 3 ) 8 (OH) 6 Nanowires.

[0023] ② The 0.0792mmolCo prepared above 11 (HPO 3 ) 8 (OH) 6Nanowires and 2.4 mmol of sodium sulfide were added to 40 mL of water and stirred to mix. The reaction solution was transferred to a reactor and reacted at 80 °C for 6.0 h. After the reaction was completed, the reaction solution was naturally cooled to room temperature. The product was centrifuged, washed with water several times and dried to obtain Co 11 (HPO 3 ) 8 (OH) 6 / Co 9 S 8 Nanotubes.

[0024] Attached Figure 2 Where a, b and c are the obtained Co 11 (HPO 3 ) 8 (OH) 6 The scanning electron microscope photo of the compound shows that its microstructure is nanowires. Figure 2 The transmission electron microscope photo in the middle (d) shows that the nanowire is a solid structure with a diameter of about 130nm. 11 (HPO 3 ) 8 (OH) 6 The compound turned black after hydrothermal sulfidation in sodium sulfide aqueous solution at 80℃ for 6.0h. Figure 3 The X-ray powder diffraction pattern of the product is shown in the attached figure. Figure 3 As shown, the diffraction peaks are consistent with Co 9 S 8 (Standard Card JCPDS:19-0364) and Co 11 (HPO 3 ) 8 (OH) 6 (Standard Card JCPDS: 44-1326) is consistent, which shows that the product after sulfurization is Co 9 S 8 and Co 11 (HPO 3 ) 8 (OH) 6 Composition. Figure 2 e and f are Co 11 (HPO 3 ) 8 (OH) 6 / Co 9 S 8 The scanning electron microscope photo shows that the obtained Co 11 (HPO 3 ) 8 (OH) 6 / Co 9 S 8The morphology of the nanowires remains one-dimensional. Figure 2 g shows that the nanowires become hollow structures after sulfurization. Figure 2 h in the equation is Co 11 (HPO 3 ) 8 (OH) 6 / Co 9 S 8 Transmission electron microscopy image, which shows that Co 11 (HPO 3 ) 8 (OH) 6 / Co 9 S 8 It is indeed a hollow structure. Figure 2 i stands for Co 11 (HPO 3 ) 8 (OH) 6 / Co 9 S 8 Electron diffraction and high-resolution transmission electron microscopy images of the nanotube selected area (1). Figure 2 The illustration in the figure is an electron diffraction pattern, and the diffraction ring 2 corresponds to Co 9 S 8 The (222) crystal plane and diffraction ring 3 correspond to Co 11 (HPO 3 ) 8 The lattice fringe spacing d is 0.31nm(4) and 0.286nm(5), corresponding to Co 11 (HPO 3 ) 8 The (310) crystal plane and Co 9 S 8 (222) crystal plane, which is consistent with the results of electron diffraction. Figure 2 The j in the middle is Co 11 (HPO 3 ) 8 (OH) 6 / Co 9 S 8 Dark field scanning transmission electron microscopy photos of nanotubes and elemental composition imaging, the results show that Co, P, O and S elements are evenly distributed in the Co 11 (HPO 3 ) 8 (OH) 6 / Co 9 S 8 in nanotubes. Figure 4 For Co 11 (HPO 3 ) 8 (OH) 6 / Co9 S 8 The nitrogen adsorption-desorption curve of the nanotubes shows that Co 11 (HPO 3 ) 8 (OH) 6 / Co 9 S 8 The specific surface area of ​​the nanotube is 103.5m 2 g -1 .Co 11 (HPO 3 ) 8 (OH) 6 / Co 9 S 8 Nanotubes have a higher specific surface area, which will generate more transmission channels for electrons and ions, and can effectively promote the migration of electrons and ions. 11 (HPO 3 ) 8 (OH) 6 / Co 9 S 8 Nanotubes have multiple electrochemical metal sites. Therefore, Co 11 (HPO 3 ) 8 (OH) 6 / Co 9 S 8 Nanotubes have a promising application prospect in supercapacitors. Figure 5 a in the equation is Co 11 (HPO 3 ) 8 (OH) 6 / Co 9 S 8 The cyclic voltammetry curves of the nanotubes at different scan rates show that all of them have a pair of obvious redox peaks, indicating that the charging and discharging process of the material is based on redox reactions. Figure 5 b is the charge and discharge curve at different current densities. Figure 5 In c, it can be concluded that the material has a g -1 When the capacitance is 1218, 1098.3, 1022, 918.8 and 805 F g -1 . Figure 5 The charge-discharge cycle stability curve is shown in Figure d. -1 After 10,000 charge and discharge cycles, its capacity can still reach 920Fg -1 , indicating that Co 11 (HPO 3 ) 8 (OH)6 / Co 9 S 8 Nanotubes have good charge and discharge cycle stability. This electrode material has good electrochemical performance compared to other hollow electrode materials, such as hollow ellipsoidal NiCo 2 S 4 (10A g -1 -495F g -1 ,Electrochim.Acta.,2016,214,76-84.); Mo-doped CoS nanocages (0.5A g -1 -781F g -1 , decayed by 53.2% after 5000 charge and discharge cycles, Inorg.Chem.Front., 2019, 6, 2178-2184.); Hollow spherical CuCo 2 S 4 (1.0Ag -1 -1069F g -1 , decayed by 6.3% after 10,000 charge and discharge cycles, Inorg.Chem.Front., 2020, 7, 603-609.); Hollow MnS-MoS 2 Cube (1.0A g -1 -1713.4F g -1 , decayed by 3.2% after 1000 charge and discharge cycles, J.Mater.Chem.A., 2022, 10, 9370-9379.); Hollow core-shell NiCo 2 S 4 / MoS 2 (1.0A g -1 -860F g -1 , after 1000 charge and discharge cycles, the decay rate was 28.1%, New J. Chem., 2019, 43, 3601-3608.) and hollow double-shell MnCo 2 S 4 / CoS 1.097 (1.0A g -1 -1006Fg -1 , after 5000 charge and discharge cycles, the decay is 8.7%, J.Power Sources., 2018, 408, 65-73.) etc. In summary, the Co 11 (HPO 3 ) 8 (OH) 6 / Co 9 S 8 Nanotubes have good application value in supercapacitor devices.

[0025] Example 2

[0026] ① Add 0.1mmol of cobalt chloride hexahydrate and 0.1mmol of sodium pyrophosphate into 20mL of water, stir and mix, transfer the reaction solution into a reactor, react at 220℃ for 6 days, and after the reaction is completed, cool naturally to room temperature, centrifuge the product, wash with water several times and dry to obtain Co 11 (HPO 3 ) 8 (OH) 6 Nanowires.

[0027] ② The 0.0144mmolCo prepared above 11 (HPO 3 ) 8 (OH) 6 Nanowires and 0.8 mmol of sodium sulfide were added to 40 mL of water and stirred to mix. The reaction solution was transferred to a reactor and reacted at 100 °C for 6.0 h. After the reaction was completed, the reaction solution was naturally cooled to room temperature. The product was centrifuged, washed with water several times and dried to obtain Co 11 (HPO 3 ) 8 (OH) 6 / Co 9 S 8 Nanotubes.

[0028] Example 3

[0029] ① Add 0.4mmol of cobalt chloride hexahydrate and 0.4mmol of sodium pyrophosphate into 20mL of water, stir and mix, transfer the reaction solution into a reactor, react at 200℃ for 6 days, and after the reaction is completed, cool naturally to room temperature, centrifuge the product, wash with water several times and dry to obtain Co 11 (HPO 3 ) 8 (OH) 6 Nanowires.

[0030] ② The 0.04mmolCo prepared above 11 (HPO 3 ) 8 (OH) 6 Nanowires and 1.6 mmol of sodium sulfide were added to 40 mL of water and stirred to mix. The reaction solution was transferred to a reactor and reacted at 80 °C for 6.0 h. After the reaction was completed, the reaction solution was naturally cooled to room temperature. The product was centrifuged, washed with water several times and dried to obtain Co 11 (HPO 3 ) 8 (OH) 6 / Co 9 S 8 Nanotubes.

[0031] Example 4

[0032] ① Add 2.0mmol of cobalt chloride hexahydrate and 2.0mmol of sodium pyrophosphate into 20mL of water, stir and mix, transfer the reaction solution into a reactor, react at 180℃ for 6 days, and after the reaction is completed, cool naturally to room temperature, centrifuge the product, wash with water several times and dry to obtain Co 11 (HPO 3 ) 8 (OH) 6 Nanowires.

[0033] ② The 0.144mmolCo prepared above 11 (HPO 3 ) 8 (OH) 6 Nanowires and 4 mmol of sodium sulfide were added to 40 mL of water, stirred and mixed, and the reaction solution was transferred to a reactor and reacted at 70 ° C for 6.0 h. After the reaction was completed, it was naturally cooled to room temperature, and the product was centrifuged, washed with water several times and dried to obtain Co 11 (HPO 3 ) 8 (OH) 6 / Co 9 S 8 Nanotubes.

Claims

1. Co 11 (HPO3)8(OH)6 / Co9S8 nanotube composite electrode material, characterized in that: It is a tubular structure, which is prepared by the following steps: 1) Co 11 Preparation of (HPO3)8(OH)6 nanowires: Add cobalt salt and pyrophosphate to water, stir and mix to prepare a reaction solution; transfer the reaction solution to a reactor, heat and react, and after the reaction is completed, naturally cool to room temperature; The product was centrifuged, washed and dried to obtain Co 11 (HPO3)8(OH)6 nanowires; 2) Co 11 Preparation of (HPO3)8(OH)6 / Co9S8 nanotubes: Co prepared in step 1) 11 (HPO3)8(OH)6 nanowires were sulfided in a sulfide salt solution to obtain Co 11 (HPO3)8(OH)6 / Co9S8 nanotube composite electrode material; The cobalt salt is cobalt chloride hexahydrate, the pyrophosphate is sodium pyrophosphate, and the sulfide salt is sodium sulfide.

2. The Co according to claim 1 11 (HPO3)8(OH)6 / Co9S8 nanotube composite electrode material, characterized in that: In step 1), the concentration of cobalt salt in the reaction solution is 0.005-0.1 mol•L -1 , the concentration of pyrophosphate is 0.005~0.1 mol•L -1 The molar ratio of cobalt salt to pyrophosphate is 1:1, and the concentration of sodium sulfide in step 2) is 0.02-0.1 mol•L -1 ,Co 11 The concentration of (HPO3)8(OH)6 is 3.6 × 10 -4 ~3.6 × 10 -3 mol•L -1 ,Co 11 The molar ratio between (HPO3)8(OH)6 and sodium sulfide is 0.018:1 to 0.036:1.

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