Ball-in-ball layered nickel-cobalt hydroxide / nickel-cobalt sulfide microspheres and preparation method and application thereof

Abstract

The invention discloses a sphere-in-sphere layered nickel-cobalt hydroxide / nickel-cobalt sulfide microsphere as well as a preparation method and application thereof. According to the preparation method of the sphere-in-sphere layered nickel-cobalt hydroxide microspheres, metal cobalt salt, nickel salt, an alkali source and a surfactant are mixed and then subjected to a hydrothermal reaction in a water / alcohol system, and the sphere-in-sphere layered nickel-cobalt hydroxide microspheres uniform in morphology are obtained through the reaction. And heating and vulcanizing the sphere-in-sphere layered nickel-cobalt hydroxide microspheres and a sulfur source in a reaction system to obtain the sphere-in-sphere nickel-cobalt sulfide microspheres. The method has the advantages of simple process, safe operation and wide applicability, and overcomes the problems of non-uniform particle size, impure phase, uncontrollable synthesis process, high cost and energy consumption and the like of particles prepared by the existing synthesis route. The product prepared by the method is novel in morphology and obvious in ball-in-ball structure characteristic, and has wide application prospects in the aspects of supercapacitors, electro-catalysis and the like.

Description

Technical Field

[0001] The invention belongs to the field of material preparation, and specifically relates to ball-in-ball layered nickel-cobalt hydroxide microspheres, ball-in-ball nickel-cobalt sulfide microspheres, and preparation methods and applications thereof. Background Art

[0002] As we all know, layered hydroxides are an important component of inorganic non-metallic functional materials. The main body is generally a two-dimensional nanostructured material formed by the interaction of divalent and trivalent metal cations and interlayer anions. At the end of the 20th century, researchers found that even in the absence of trivalent metal elements, layered materials with a hydrotalcite-like structure can still be formed. Its chemical composition is usually: M(OH) 2-x A x / n n- mH2O, called α-phase layered hydroxide. This is a new type of layered inorganic functional material with a hydrotalcite structure, which has broad application prospects in energy storage, electrocatalysis and other fields.

[0003] Combined with the original structural characteristics of the material, a variety of methods for synthesizing layered hydroxides have been developed in recent years, and layered nanoparticles with different morphological characteristics have also been prepared. D. Jiang et al. synthesized three-dimensional (3D) flower-like nickel-cobalt layered hydroxide microspheres by alkaline hydrolysis strategy (Inorg. Chem. Front., 2021, 8, 4324-4333). S. Jin et al. reported the successful preparation of Co-Ni layered hydroxides by continuous hydrothermal reaction at high temperature and high pressure (Nano. Lett., 2015, 15, 1421-1427). Enhui. Bao et al. successfully prepared CoNi layered hydroxide nanosheets by solution heat method (J. Energy. Storage., 2024, 82, 110535). However, the current methods for synthesizing layered hydroxides are still relatively complicated, and the preparation method of sphere-in-sphere layered nickel-cobalt hydroxide microspheres has not been reported. Therefore, developing a method for preparing spherical nickel-cobalt hydroxide and nickel-cobalt sulfide microspheres with simple operation, obvious product structural characteristics, uniform size, and good electrochemical properties remains an important task in the field of material preparation. Summary of the invention

[0004] The main purpose of the present invention is to provide a sphere-in-sphere layered nickel-cobalt hydroxide microsphere and sphere-in-sphere nickel-cobalt sulfide microsphere with obvious morphological characteristics and good electrochemical performance, as well as a preparation method and application thereof.

[0005] The sphere-in-sphere layered nickel-cobalt hydroxide microspheres of the present invention are composed of a solid spherical core and an outer shell of layered nickel-cobalt hydroxide, with a particle size of 2-5 μm and a shell thickness of 100-250 nm.

[0006] The ball-in-ball nickel-cobalt sulfide microsphere of the invention is composed of a solid spherical core and an outer shell of nickel-cobalt sulfide, with a particle size of 2-5 μm and a shell thickness of 100-300 nm.

[0007] The preparation method of the ball-in-ball layered nickel-cobalt hydroxide microspheres of the present invention comprises the following steps:

[0008] Step 1: mixing metal cobalt salt, nickel salt, alkali source and surfactant in a water / alcohol mixed reaction solvent system;

[0009] Step 2: The mixed solution of step 1 is placed in a high pressure reactor and heated.

[0010] The metal salts described in step 1 are cobalt nitrate hexahydrate and nickel nitrate hexahydrate, the alkali source is urea, and the surfactant is hexadecyltrimethylammonium bromide.

[0011] The molar ratio of the cobalt salt and the nickel salt in step 1 is 1:2-4, the molar ratio of the alkali source and the surfactant is 5:1-2, the molar ratio of the metal salt, the alkali source and the surfactant is 1:10:2, the water / alcohol reaction solvent is pure water and ethanol solvent, and the volume ratio of water to ethanol is 25:5 to 5:25.

[0012] The molar ratio of the metal salt, the alkali source, the surfactant and the solvent is: 1:10:2:703-1474.

[0013] Preferably, in step 1, the molar ratio of the cobalt nitrate hexahydrate to the nickel nitrate hexahydrate is 1:4, and the volume ratio of water to ethanol is 10:20 ml.

[0014] The heating temperature in step 2 is 120° C. to 200° C., the reaction time is 120° C. to 200° C., and the reaction time is 4 to 24 hours.

[0015] Preferably, the heating temperature in step 2 is 180° C. and the reaction time is 24 hours.

[0016] The volume of the autoclave is preferably 40 to 100 ml, preferably 40 ml.

[0017] The preparation method of the ball-in-ball nickel-cobalt sulfide microspheres of the present invention is as follows:

[0018] The sphere-in-sphere layered nickel-cobalt hydroxide microspheres prepared by the aforementioned preparation method are mixed with a sulfur source in an anhydrous ethanol reaction solvent system and reacted in a high-pressure reactor.

[0019] The mass ratio of the ball-in-ball layered nickel-cobalt hydroxide microspheres to the sulfur source is 3:4-6, and the sulfur source is thioacetamide.

[0020] The mass ratio of the solvent, the microspheres and the sulfur source is: 1580-2370:3:4-6.

[0021] Preferably: 0.03 g of sphere-in-sphere layered nickel cobalt hydroxide microspheres, 0.05 g of thioacetamide, and 20 ml of ethanol.

[0022] The reaction temperature in the autoclave is 120°C to 180°C for 1 to 8 hours. Preferably, the reaction is carried out at 160°C for 2 hours.

[0023] The present invention also provides the use of the sphere-in-sphere layered nickel-cobalt hydroxide microspheres or the sphere-in-sphere nickel-cobalt sulfide microspheres in supercapacitors and electrocatalytic materials.

[0024] Compared with the existing technology, the present invention has the following advantages and outstanding effects:

[0025] 1. Using a high temperature and high pressure reactor as a reactor can effectively eliminate interference from the external environment; more effectively control the reaction process, adjust the reaction parameters, and more easily obtain the target product.

[0026] 2. The present invention uses common metal cobalt and nickel salts as raw materials and pure water and ethanol as reaction solvents, which are low-priced and easily available; the addition of ionic surfactants can effectively control the morphological characteristics of the product.

[0027] 3. The present invention studies the effect of different molar ratios of cobalt and nickel salt additions on the physical phase and morphological characteristics of the synthesized material. The study found that with the increase in the amount of cobalt salt, the physical phase and morphology of the synthesized material changed significantly.

[0028] 4. The present invention studies the influence of different water / ethanol volume ratios on the physical phase and morphological characteristics of the synthetic substance. The study found that when the water / ethanol volume is 1:2, the ball-in-ball structure characteristics are most obvious.

[0029] 5. The present invention uses the synthesized sphere-in-sphere layered nickel-cobalt hydroxide microspheres as a precursor, and transfers them together with thioacetamide into a high-pressure reactor for heating and sulfidation to prepare sphere-in-sphere nickel-cobalt sulfide microspheres.

[0030] 6. The present invention is pollution-free, has controllable output, and is widely used in electrocatalysis and energy storage. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 The X-ray powder diffraction pattern of the sphere-in-sphere layered nickel-cobalt hydroxide microspheres (nickel / cobalt=4:1) prepared in Example 1;

[0032] Figure 2 This is a SEM electron microscope image of the sphere-in-sphere layered nickel-cobalt hydroxide microspheres (nickel / cobalt=4:1) prepared in Example 1;

[0033] Figure 3This is a high-magnification SEM electron microscope image of the ball-in-ball layered nickel-cobalt hydroxide microspheres (nickel / cobalt=4:1) prepared in Example 1;

[0034] Figure 4 This is a TEM electron microscope image of the sphere-in-sphere layered nickel-cobalt hydroxide microspheres (nickel / cobalt=4:1) prepared in Example 1;

[0035] Figure 5 HRTEM electron microscope image of the sphere-in-sphere layered nickel-cobalt hydroxide microspheres (nickel / cobalt=4:1) prepared in Example 1;

[0036] Figure 6 This is the GCD diagram of the sphere-in-sphere layered nickel-cobalt hydroxide microspheres (nickel / cobalt=4:1) prepared in Example 1;

[0037] Figure 7 is the X-ray powder diffraction pattern of nickel bicarbonate (nickel / cobalt=1:0) prepared in Example 2;

[0038] Figure 8 This is a SEM electron microscope image of nickel bicarbonate (nickel / cobalt=1:0) prepared in Example 2;

[0039] Fig. 9 is the X-ray powder diffraction pattern of the nickel cobalt hydroxide (nickel / cobalt=3:1) prepared in Example 3;

[0040] Fig.10 This is a SEM electron microscope image of the nickel-cobalt hydroxide (nickel / cobalt=3:1) prepared in Example 3;

[0041] Fig.11 is the X-ray powder diffraction pattern of the nickel cobalt hydroxide (nickel / cobalt=2:1) ​​prepared in Example 4;

[0042] Fig.12 This is a SEM electron microscope image of the nickel-cobalt hydroxide (nickel / cobalt=2:1) ​​prepared in Example 4;

[0043] Fig.13 GCD diagrams of nickel bicarbonate and nickel cobalt hydroxide prepared in Examples 1-4;

[0044] Fig.14 is the X-ray powder diffraction pattern of the nickel cobalt hydroxide (water / ethanol=1:5) prepared in Example 5;

[0045] Fig.15 This is a SEM electron microscope image of the nickel cobalt hydroxide (water / ethanol=1:5) prepared in Example 5;

[0046] Fig.16is the X-ray powder diffraction pattern of the nickel cobalt hydroxide (water / ethanol=1:1) prepared in Example 6;

[0047] Fig.17 This is a SEM electron microscope image of the nickel cobalt hydroxide (water / ethanol=1:1) prepared in Example 6;

[0048] Fig.18 is the X-ray powder diffraction pattern of the cobalt nickel hydroxide (water / ethanol=2:1) ​​prepared in Example 7;

[0049] Fig.19 This is a SEM electron microscope image of the cobalt nickel hydroxide (water / ethanol=2:1) ​​prepared in Example 7;

[0050] Fig. 20 is the X-ray powder diffraction pattern of the cobalt nickel hydroxide (water / ethanol=5:1) prepared in Example 8;

[0051] Fig.21 This is a SEM electron microscope image of the cobalt nickel hydroxide (water / ethanol=5:1) prepared in Example 8;

[0052] Fig. 22 is the GCD diagram of the nickel cobalt hydroxide prepared in Examples 1 and 5-8;

[0053] Fig.23 The X-ray powder diffraction pattern of the ball-in-ball nickel-cobalt sulfide microspheres prepared in Example 9;

[0054] Fig.24 This is a SEM electron microscope image of the ball-in-ball nickel-cobalt sulfide microspheres prepared in Example 9;

[0055] Fig.25 This is a high-magnification SEM electron microscope image of the ball-in-ball nickel-cobalt sulfide microspheres prepared in Example 9;

[0056] Fig.26 This is a TEM electron microscope image of the ball-in-ball nickel-cobalt sulfide microspheres prepared in Example 9;

[0057] Fig. 27 HRTEM electron microscope image of the ball-in-ball nickel-cobalt sulfide microspheres prepared in Example 9;

[0058] Fig.28 This is the GCD diagram of the sphere-in-sphere nickel-cobalt sulfide microspheres prepared in Example 9. DETAILED DESCRIPTION

[0059] The following examples are intended to further illustrate the present invention, but are not intended to limit the present invention.

[0060] Example 1

[0061] Weigh 0.8mmol (0.23g) of nickel nitrate hexahydrate and 0.2mmol (0.06g) of cobalt nitrate hexahydrate and dissolve them in the inner tank of a reactor containing 10ml of pure water and 20ml of ethanol. Then weigh 2mmol (0.73g) of hexadecyltrimethylammonium bromide and dissolve it in the mixed solvent. After stirring evenly for 10min, add 10mmol (0.60g) of urea. After stirring for 15min, transfer to a high-pressure reactor and react at 180℃ for 24 hours. The product obtained by the reaction is centrifuged, washed and dried to obtain a blue powder. Figure 1 The product was identified as layered nickel-cobalt hydroxide by X-ray powder diffraction. The morphology of the layered nickel-cobalt hydroxide was analyzed by scanning electron microscopy (SEM). Figure 2 , 3 It can be seen that its morphology is spherical with a diameter of about 2 μm; the morphology and structure of layered nickel-cobalt hydroxide were analyzed by transmission electron microscopy (TEM). Figure 4 It can be seen that it is a ball-in-ball structure; and combined with Figure 5 The HRTEM images in further prove that the synthesized material is a layered nickel-cobalt hydroxide with good crystallinity; Figure 6 This is the GCD image of sphere-in-sphere layered nickel-cobalt hydroxide microspheres, showing that they have excellent electrochemical properties as supercapacitors.

[0062] Example 2

[0063] Weigh 1mmol (0.29g) of nickel nitrate hexahydrate and dissolve it in the inner tank of a reactor containing 10ml of pure water and 20ml of ethanol. Then weigh 2mmol (0.73g) of hexadecyltrimethylammonium bromide and dissolve it in the mixed solvent. After stirring evenly for 10min, add 10mmol (0.60g) of urea. Continue stirring for 15min and transfer to a high-pressure reactor. React at 180℃ for 24 hours. The product obtained by the reaction is centrifuged, washed and dried to obtain a green powder. Figure 7 The product was identified as nickel bicarbonate by X-ray powder diffraction. The morphology of the product was analyzed by scanning electron microscopy (SEM). Figure 8 It can be seen that the morphology is nickel bicarbonate microspheres and nanosheets. Fig.13 The GCD images show that the electrochemical performance of nickel bicarbonate (nickel / cobalt = 1:0) is weaker than that of the sphere-in-sphere layered nickel cobalt hydroxide microspheres (nickel / cobalt = 4:1, i.e., Example 1).

[0064] Example 3

[0065] Weigh 0.75mmol (0.22g) of nickel nitrate hexahydrate and 0.25mmol (0.07g) of cobalt nitrate hexahydrate and dissolve them in the inner tank of a reactor containing 10ml of pure water and 20ml of ethanol. Then weigh 2mmol (0.73g) of hexadecyltrimethylammonium bromide and dissolve it in the mixed solvent. After stirring evenly for 10min, add 10mmol (0.60g) of urea. After stirring for 15min, transfer to a high-pressure reactor and react at 180°C for 24 hours. The product obtained by the reaction is centrifuged, washed, and dried to obtain a blue powder. Fig. 9 The product was identified as layered nickel-cobalt hydroxide by X-ray powder diffraction. The morphology of the product was analyzed by scanning electron microscopy (SEM). Fig.10 It can be seen that its morphology is nickel cobalt hydroxide microspheres and microspheres. Fig.13 The GCD images show that the electrochemical performance of nickel cobalt hydroxide (nickel / cobalt = 3:1) is weaker than that of sphere-in-sphere layered nickel cobalt hydroxide microspheres (nickel / cobalt = 4:1).

[0066] Example 4

[0067] Weigh 0.67mmol (0.19g) of nickel nitrate hexahydrate and 0.33mmol (0.10g) of cobalt nitrate hexahydrate and dissolve them in the inner tank of a reactor containing 10ml of pure water and 20ml of ethanol. Then weigh 2mmol (0.73g) of hexadecyltrimethylammonium bromide and dissolve it in the mixed solvent. After stirring evenly for 10min, add 10mmol (0.60g) of urea. After stirring for 15min, transfer to a high-pressure reactor and react at 180°C for 24 hours. The product obtained by the reaction is centrifuged, washed, and dried to obtain a blue powder. Fig.11 The product was identified as layered nickel-cobalt hydroxide by X-ray powder diffraction. The morphology of the product was analyzed by scanning electron microscopy (SEM). Fig.12 It can be seen that the morphology is nickel cobalt hydroxide microspheres and nanowires. Fig.13 The GCD images show that the electrochemical performance of nickel cobalt hydroxide (nickel / cobalt = 2:1) is weaker than that of sphere-in-sphere layered nickel cobalt hydroxide microspheres (nickel / cobalt = 4:1).

[0068] Example 5

[0069] Weigh 0.8mmol (0.23g) of nickel nitrate hexahydrate and 0.2mmol (0.06g) of cobalt nitrate hexahydrate and dissolve them in the inner tank of a reactor containing 5ml of pure water and 25ml of ethanol. Then weigh 2mmol (0.73g) of hexadecyltrimethylammonium bromide and dissolve them in the mixed solvent. After stirring evenly for 10min, add 10mmol (0.60g) of urea, continue stirring for 15min, transfer to a high-pressure reactor, and react at 180°C for 24 hours. The product obtained by the reaction is centrifuged, washed, and dried to obtain a blue powder. Fig.14 The product was identified as layered nickel-cobalt hydroxide by X-ray powder diffraction. The morphology of the product was analyzed by scanning electron microscopy (SEM). Fig.15 It can be seen that its morphology is microspheres and microflower balls. Fig. 22 The GCD images show that the electrochemical performance of nickel cobalt hydroxide (water / ethanol = 1:5) is weaker than that of sphere-in-sphere layered nickel cobalt hydroxide microspheres (water / ethanol = 1:2).

[0070] Example 6

[0071] Weigh 0.8mmol (0.23g) of nickel nitrate hexahydrate and 0.2mmol (0.06g) of cobalt nitrate hexahydrate and dissolve them in the inner tank of a reactor containing 15ml of pure water and 15ml of ethanol. Then weigh 2mmol (0.73g) of hexadecyltrimethylammonium bromide and dissolve it in the mixed solvent. After stirring evenly for 10min, add 10mmol (0.60g) of urea. After stirring for 15min, transfer to a high-pressure reactor and react at 180°C for 24 hours. The product obtained by the reaction is centrifuged, washed, and dried to obtain a blue powder. Fig.16 The product was identified as layered nickel-cobalt hydroxide by X-ray powder diffraction. The morphology of the product was analyzed by scanning electron microscopy (SEM). Fig.17 It can be seen that its morphology is microspheres and microflower balls. Fig. 22 The GCD images show that the electrochemical performance of nickel cobalt hydroxide (water / ethanol = 1:1) is weaker than that of sphere-in-sphere layered nickel cobalt hydroxide microspheres (water / ethanol = 1:2).

[0072] Example 7

[0073] Weigh 0.8mmol (0.23g) of nickel nitrate hexahydrate and 0.2mmol (0.06g) of cobalt nitrate hexahydrate and dissolve them in the inner tank of a reactor containing 20ml of pure water and 10ml of ethanol. Then weigh 2mmol (0.73g) of hexadecyltrimethylammonium bromide and dissolve it in the mixed solvent. After stirring evenly for 10min, add 10mmol (0.60g) of urea. After stirring for 15min, transfer to a high-pressure reactor and react at 180℃ for 24 hours. The product obtained by the reaction is centrifuged, washed and dried to obtain a blue powder. Fig.18 The product was identified as cobalt nickel hydroxide by X-ray powder diffraction. The morphology of the product was analyzed by scanning electron microscopy (SEM). Fig.19 It can be seen that its morphology is microspheres and nanowires. Fig. 22 The GCD images show that the electrochemical performance of cobalt nickel hydroxide (water / ethanol = 2:1) is weaker than that of sphere-in-sphere layered nickel cobalt hydroxide microspheres (water / ethanol = 1:2).

[0074] Example 8

[0075] Weigh 0.8mmol (0.23g) of nickel nitrate hexahydrate and 0.2mmol (0.06g) of cobalt nitrate hexahydrate and dissolve them in the inner tank of a reactor containing 25ml of pure water and 5ml of ethanol. Then weigh 2mmol (0.73g) of hexadecyltrimethylammonium bromide and dissolve them in the mixed solvent. After stirring evenly for 10min, add 10mmol (0.60g) of urea. After stirring for 15min, transfer to a high-pressure reactor and react at 180℃ for 24 hours. The product obtained by the reaction is centrifuged, washed and dried to obtain a blue powder. Fig. 20 The product was identified as cobalt nickel hydroxide by X-ray powder diffraction. The morphology of the product was analyzed by scanning electron microscopy (SEM). Fig.21 It can be seen that its morphology is microspheres and nanowires. Fig. 22 The GCD images show that the electrochemical performance of cobalt nickel hydroxide (water / ethanol = 5:1) is weaker than that of sphere-in-sphere layered nickel cobalt hydroxide microspheres (water / ethanol = 1:2).

[0076] Example 9

[0077] Weigh 0.03 g of the spherical layered nickel-cobalt hydroxide synthesized in Example 1 and dissolve it in the inner container of a reactor containing 20 ml of ethanol, then weigh 0.05 g of thioacetamide and dissolve it in the reaction solvent, and stir evenly for 25 minutes. Transfer to a high-pressure reactor and react at 160°C for 2 hours. The product obtained by the reaction is centrifuged, washed, and dried to obtain a black powder. Fig.23The product was identified as nickel-cobalt sulfide by X-ray powder diffraction. The morphology of nickel-cobalt sulfide was analyzed by scanning electron microscopy (SEM). Fig.24 , 25 It can be seen that its morphology is spherical with a diameter of about 2μm; the morphology and structure of nickel-cobalt sulfide were analyzed by transmission electron microscopy (TEM). Fig.26 It can be seen that it is a ball-in-ball structure; and combined with Fig. 27 The HRTEM images in further prove that the synthesized material is a nickel-cobalt sulfide with good crystallinity; Fig.28 This is the GCD image of sphere-in-sphere nickel-cobalt sulfide microspheres, showing that they have excellent electrochemical properties as supercapacitors.

Claims

1. Ball-in-ball layered nickel-cobalt hydroxide microspheres, characterized in that: It is composed of a solid spherical core and an outer shell of layered nickel-cobalt hydroxide, with a particle size of 2 to 5 μm and a shell thickness of 100 to 250 nm.

2. Ball-in-ball nickel-cobalt sulfide microspheres, characterized in that: It is composed of a solid spherical core and an outer shell of nickel-cobalt sulfide, with a particle size of 2 to 5 μm and a shell thickness of 100 to 300 nm.

3. A method for preparing ball-in-ball layered nickel-cobalt hydroxide microspheres, characterized in that: The following steps are involved: Step 1: mixing metal cobalt salt, nickel salt, alkali source and surfactant in a water / alcohol mixed reaction solvent system; Step 2: Place the mixed solution of step 1 in a high pressure reactor and heat it.

4. The preparation method according to claim 3, characterized in that: The metal salts described in step 1 are cobalt nitrate hexahydrate and nickel nitrate hexahydrate, the alkali source is urea, and the surfactant is hexadecyltrimethylammonium bromide.

5. The preparation method according to claim 3, characterized in that: The molar ratio of the cobalt salt and the nickel salt in step 1 is 1:2-4, the molar ratio of the alkali source and the surfactant is 5:1-2, the molar ratio of the metal salt, the alkali source and the surfactant is 1:10:2, the water / alcohol reaction solvent is pure water and ethanol solvent, and the volume ratio of water to ethanol is 25:5 to 5:

25.

6. The preparation method according to claim 3, characterized in that: The heating temperature in step 2 is 120 to 200° C., and the reaction time is 4 to 24 hours.

7. A method for preparing ball-in-ball nickel-cobalt sulfide microspheres, characterized in that: The sphere-in-sphere nickel-cobalt hydroxide microspheres prepared by the preparation method described in claims 3-6 are mixed with a sulfur source in an anhydrous ethanol reaction solvent system and reacted in a high-pressure reactor.

8. The preparation method according to claim 7, characterized in that: The mass ratio of the ball-in-ball layered nickel-cobalt hydroxide microspheres to the sulfur source is 3:4-6, and the sulfur source is thioacetamide.

9. The preparation method according to claim 7, characterized in that: The reaction temperature in the high-pressure reactor is 120°C to 200°C, and the heating is performed for 1 to 8 hours.

10. Use of the sphere-in-sphere layered nickel cobalt hydroxide microspheres according to claim 1, or the sphere-in-sphere layered nickel cobalt hydroxide microspheres prepared by the method of any one of claims 3 to 6, or the sphere-in-sphere nickel cobalt sulfide microspheres according to claim 2, or the sphere-in-sphere nickel cobalt sulfide microspheres prepared by the method of any one of claims 7 to 9 in supercapacitors and electrocatalytic materials.

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