CN100558646C - A kind of sub-micrometer flower-shape Ni (OH) 2The preparation method - Google Patents

Abstract

A kind of sub-micrometer flower-shape Ni (OH) ₂The preparation method, belong to field of nanometer material technology.This preparation method adds earlier hydrofluoric acid in nickel salt solution, the fluorine atom coordination in nickel ion and the solution generates [NiFx] ^(x-2)-Add ammoniacal liquor then, control pH value of solution value is 7.5～8.8, and heating in water bath solution makes its temperature maintenance at 50～80 ℃, reacts 2～4 hours, obtains sub-micrometer flower-shape Ni (OH) ₂Technology of the present invention is simple, efficient reaction conditions is easy to control fast, has obtained the Ni (OH) of the big sub-micrometer flower-shape of specific surface area ₂Assembly has overcome nanometer Ni (OH) ₂Reunion in actual use and particle crane span structure problem.The Ni of this sub-micrometer flower-shape (OH) ₂Assembly has significant using value in high energy density cells.

Description

A kind of sub-micrometer flower-shape Ni (OH) 2The preparation method

Technical field

The present invention relates to a kind of sub-micrometer flower-shape Ni (OH) with nanostructure ₂The preparation method, belong to field of nanometer material technology.

Background technology

Ni (OH) ₂As the positive electrode active materials of multiple Edison battery (Ni/Cd, Ni/Zn, Ni/MH, Ni/Fe), capacity, life-span and the chemical property of battery played a crucial role.Preparation heavy body, highly active Ni (OH) ₂Positive electrode active materials becomes both at home and abroad the competitively focus of research.With common micron spherical Ni (OH) ₂Compare nanometer Ni (OH) ₂Have higher proton shifting speed, littler grain resistance, activating velocity faster.Therefore, nanometer Ni (OH) ₂The development of material has more important meaning to the development of nickel series battery.

The coordination precipitation method is easy to produce the nanometer Ni for preparing (OH) because to have a technological principle simple, easy to operate ₂Controllable granularity, therefore characteristics such as size distribution is narrower are to prepare the more feasible method of nano-sized nickel hydroxide electrode materials, the test work that is particularly useful for producing in enormous quantities.The coordination precipitation method be with coordination agent with suitable proportioning effect and nickel salt aqueous solution, form the title complex of nickel, under the caustic alkali effect, nickel ion is released at leisure then, and and OH ^-Reaction generates nanometer Ni (OH) ₂Coordination agent in the bibliographical information is generally ammoniacal liquor, oxalic acid, quadrol etc.The nanometer Ni (OH) that adopts the coordination precipitation method to prepare ₂Powder often is needle-like and flaky texture, and these structures independently exist separately, can not be combined into certain shape.This nanometer Ni (OH) that does not have specified shape ₂As Ni (OH) ₂The additive of electrode has serious reunion and particle crane span structure phenomenon in the use of reality, thereby causes producing very big space between particle, and the powder free-running property is relatively poor.This is nanometer Ni (OH) ₂So far still be not applied to the one of the main reasons in the battery production.Therefore synthesize nanometer Ni (OH) with definite shape ₂Assembly will have important use and be worth in high energy density cells.

Summary of the invention

The problem that will solve required for the present invention provides a kind of nanometer Ni (OH) of specified shape ₂Assembly and preparation method thereof.The sub-micrometer flower-shape Ni that the present invention obtains (OH) ₂The particulate diameter is 500～1400nm, and particle is about 20～100nm by thickness, and width is about the petal of 80～250m and forms, the big (78～189m of specific surface area ²/ g), have nanometer Ni (OH) ₂Character.In different experiment condition scopes, this sub-micrometer flower-shape Ni (OH) ₂Crystal formation can be α-Ni (OH) ₂Crystal formation, perhaps α/β-Ni (OH) ₂Mix crystal formation.

The present invention adopts fluorine atom as ligating atom, adds hydrofluoric acid and generate [NiF in the solution of nickel salt _x] ^(x-2)-, in solution, add the OH that ammoniacal liquor provides nickel coordination ion hydrolytic precipitation to need as precipitation agent then ^-, the slow hydrolytic condensation of nickel coordination ion has obtained sub-micrometer flower-shape Ni (OH) ₂

The invention provides a kind of sub-micrometer flower-shape Ni (OH) ₂The preparation method, it is characterized in that step is as follows:

1) is made into the solution that concentration is 0.01～0.1mol/L with the solid divalent nickel salt is soluble in water;

2) hydrofluoric acid is added obtain mixing solutions in the nickel salt solution, F and Ni (II) atomic ratio is between 1: 1～7: 1 in the solution;

3) in above-mentioned mixing solutions slowly the pH value of dropping ammonia regulator solution between 7.5～8.8;

4) will regulate solution after the pH value and put into 50 ℃～80 ℃ water-bath reacting by heating 2～4 hours;

5) precipitate and separate, collection, washing, drying are obtained green Ni (OH) ₂Powder.

Reaction mechanism of the present invention is:

Adopt fluorine atom as ligating atom, the hydrofluoric acid coordination in nickel ion and the solution generates [NiF _x] ^(x-2)-, shown in chemical equation (1).Wherein, metallic nickel can be regulated by the add-on that changes nickel salt solution and hydrofluoric acid solution with the fluorine atom ratio.[NiF _x] ^(x-2)-In the aqueous solution, there is the hydrolysising balance reaction, generates [NiF _X-n(OH) _n] ^(x-2)-And HF, shown in chemical equation (2).Along with the adding of ammoniacal liquor, OH in the solution ^-Increase (shown in chemical equation (3)), driving a reaction (2) carries out to the right.When hydrolysis reaction proceeds to a certain degree [NiF _x] ^(x-2)-Complete hydrolysis forms [Ni (OH) _x] ^(x-2)-[Ni (OH) _x] ^(x-2)-Between condensation reaction takes place generates Ni (OH) ₂Precipitation.When the temperature of solution is raised to 50 ℃～80 ℃ by room temperature, Ni in the solution (OH) ₂Degree of supersaturation increase Ni (OH) rapidly ₂Be deposited in nucleation in the solution, growing up forms Ni (OH) ₂Particle.

Experiment condition of the present invention is simple, and preparation process can be carried out at normal temperatures, and operation is simple, can obtain the Ni (OH) of diverse microcosmic structure and crystal formation ₂Flower-shaped particle.This Ni (OH) ₂Flower-shaped particle has nanometer Ni (OH) ₂Character, and can be as Ni (OH) ₂The additive of electrode or direct Ni (OH) ₂Electrode active material uses as reality.

Description of drawings

The Ni (OH) that Fig. 1 example 1 of the present invention obtains ₂The SEM photo of the low magnification of powder

The Ni (OH) that Fig. 2 example 1 of the present invention obtains ₂The SEM photo of the high-amplification-factor of powder

The Ni (OH) that Fig. 3 example 1 of the present invention obtains ₂Powder XRD curve

The Ni (OH) that Fig. 4 example 2 of the present invention obtains ₂The SEM photo of the low magnification of powder

The Ni (OH) that Fig. 5 example 2 of the present invention obtains ₂The SEM photo of the high-amplification-factor of powder

The Ni (OH) that Fig. 6 example 2 of the present invention obtains ₂The XRD curve of powder

The Ni (OH) that Fig. 7 example 3 of the present invention obtains ₂The SEM photo of the low magnification of powder

The Ni (OH) that Fig. 8 example 3 of the present invention obtains ₂The SEM photo of the high-amplification-factor of powder

The Ni (OH) that Fig. 9 example 3 of the present invention obtains ₂The XRD curve of powder

The Ni (OH) that Figure 10 example 4 of the present invention obtains ₂The SEM photo of the low magnification of powder

The Ni (OH) that Figure 11 example 4 of the present invention obtains ₂The SEM photo of the high-amplification-factor of powder

Embodiment

Below in conjunction with specific embodiment, the invention will be further described.

Example 1 is with a certain amount of solid NiCl ₂6H ₂O is dissolved in the 100ml distilled water, obtains green NiCl ₂The aqueous solution.Wherein, Ni (II) volumetric molar concentration is 0.03mol/L in the solution.At NiCl ₂The adding mass concentration is 40% hydrofluoric acid in the aqueous solution, and Ni in the regulator solution (II) is 1: 3 with the F atomic ratio.Then, slow dropping mass concentration is 25% ammoniacal liquor in above-mentioned mixing solutions, regulator solution pH value to 8.3.Mixing solutions placed 60 ℃ water-bath reacting by heating 2 hours.Solution centrifugal, washing, oven dry that reaction is obtained obtain green Ni (OH) ₂Powder.

The Ni that from Fig. 1 and Fig. 2, obtains as can be seen (OH) ₂The powder microscopic appearance is flower-shaped spherical granules, and median size is about 1300nm, and petal thickness is 80nm, and width is 230nm.Petal is arranged tightr.The green powder that obtains as can be seen from Figure 3 is α/β-Ni (OH) ₂Mix crystal formation.The BET specific surface area is 98.17m ²/ g, productive rate are 82.8%.

Example 2 is with a certain amount of solid NiCl ₂6H ₂O is dissolved in the 100ml distilled water, obtains green NiCl ₂The aqueous solution.Wherein, Ni (II) volumetric molar concentration is 0.03mol/L in the solution.At NiCl ₂The adding mass concentration is 40% hydrofluoric acid in the aqueous solution, and Ni in the regulator solution (II) is 1: 3 with the F atomic ratio.Then, slow dropping mass concentration is 25% ammoniacal liquor in above-mentioned mixing solutions, regulator solution pH value to 8.8.Mixing solutions placed 60 ℃ water-bath reacting by heating 2 hours.Solution centrifugal, washing, oven dry that reaction is obtained obtain green Ni (OH) ₂Powder.

The Ni that from Fig. 4 and Fig. 5, obtains as can be seen (OH) ₂The powder microscopic appearance is flower-shaped spherical granules, and median size is about 600nm, and petal thickness is 55nm, and width is 110nm, and petal presents loose distribution.The green powder that obtains as can be seen from Figure 6 is α/β-Ni (OH) ₂Mix crystal formation.The BET specific surface area is 118.13m ²/ g, productive rate are 64.4%

Example 3 is with a certain amount of solid NiCl ₂6H ₂O is dissolved in the 100ml distilled water, obtains green NiCl ₂The aqueous solution.Wherein, Ni (II) volumetric molar concentration is 0.03mol/L in the solution.At NiCl ₂The adding mass concentration is 40% hydrofluoric acid in the aqueous solution, and Ni in the regulator solution (II) is 1: 6 with the F atomic ratio.Then, slow dropping mass concentration is 25% ammoniacal liquor in above-mentioned mixing solutions, regulator solution pH value to 8.0.Mixing solutions placed 60 ℃ stirred in water bath, reacting by heating 2 hours.Solution centrifugal, washing, oven dry that reaction is obtained obtain green Ni (OH) ₂Powder.

The Ni that from Fig. 7 and Fig. 8, obtains as can be seen (OH) ₂The powder microscopic appearance is flower-shaped spherical granules, and median size is about 800nm, and petal thickness is 60nm, and width is 160nm, and petal presents more closely to be arranged.The green powder that obtains as can be seen from Figure 9 is α-Ni (OH) ₂Crystal formation.The BET specific surface area is 99.94m ²/ g, productive rate are 74.4%

Example 4 is with a certain amount of solid NiCl ₂6H ₂O is dissolved in the 100ml distilled water, obtains green NiCl ₂The aqueous solution.Wherein, Ni (II) volumetric molar concentration is 0.03mol/L in the solution.At NiCl ₂The adding mass concentration is 40% hydrofluoric acid in the aqueous solution, and Ni in the regulator solution (II), F atomic ratio are taken as 1: 6.Then, slow dropping mass concentration is 25% ammoniacal liquor in above-mentioned mixing solutions, regulator solution pH value to 8.0.Mixing solutions placed 80 ℃ water-bath reacting by heating 4 hours.Solution centrifugal, washing, oven dry that reaction is obtained obtain green Ni (OH) ₂Powder.

The Ni that from Figure 10 and Figure 11, obtains as can be seen (OH) ₂The powder microscopic appearance is flower-shaped spherical granules, and median size is about 1400nm, and petal thickness is 100nmm, and width is 250nm, and petal presents more closely to be arranged.Through X-ray diffraction proof gained green powder is α/β-Ni (OH) ₂Mix crystal formation.The BET specific surface area is 183.20m ²/ g, productive rate are 68.8%.

Example 5 is with a certain amount of solid NiCl ₂6H ₂O is dissolved in the 100ml distilled water, obtains green NiCl ₂The aqueous solution.Wherein, Ni (II) volumetric molar concentration is 0.03mol/L in the solution.At NiCl ₂The adding mass concentration is 40% hydrofluoric acid in the aqueous solution, and Ni in the regulator solution (II) is 1: 3 with the F atomic ratio.Then, slow dropping mass concentration is 25% ammoniacal liquor in above-mentioned mixing solutions, regulator solution pH value to 7.5.Mixing solutions placed 60 ℃ water-bath reacting by heating 2 hours.Solution centrifugal, washing, oven dry that reaction is obtained obtain green Ni (OH) ₂Powder.

Scanning electron microscope characterizes all flower-shaped spherical granules of sample, and median size is about 700nm, and petal thickness is 50nm, and width is 80nm.Petal is arranged tightr.Through X-ray diffraction proof gained green powder is α-Ni (OH) ₂Crystal formation.The BET specific surface area is 88.41m ²/ g, productive rate are 40.1%.

Example 6 is with a certain amount of solid NiCl ₂6H ₂O is dissolved in the 100ml distilled water, obtains green NiCl ₂The aqueous solution.Wherein, Ni (II) volumetric molar concentration is 0.03mol/L in the solution.At NiCl ₂The adding mass concentration is 40% hydrofluoric acid in the aqueous solution, and Ni in the regulator solution (II) is 1: 1 with the F atomic ratio.Then, be 25% ammoniacal liquor in above-mentioned mixed solution and dripping mass concentration, regulator solution pH value to 8.0.Mixing solutions placed 50 ℃ water-bath reacting by heating 2 hours.Solution centrifugal, washing, oven dry that reaction is obtained obtain green Ni (OH) ₂Powder.

Scanning electron microscope characterizes all flower-shaped spherical granules of sample, and median size is about 900nm, and petal thickness is 30nm, and width is 180nm, and petal presents than loose arrangement.Through X-ray diffraction proof gained green powder is α/β-Ni (OH) ₂Mix crystal formation.The BET specific surface area is 189.51m ²/ g, productive rate are 69.4%.

Example 7 is with a certain amount of solid NiCl ₂6H ₂O is dissolved in the 100ml distilled water, obtains green NiCl ₂The aqueous solution.Wherein, Ni (II) volumetric molar concentration is 0.03mol/L in the solution.At NiCl ₂The adding mass concentration is 40% hydrofluoric acid in the aqueous solution, and Ni in the regulator solution (II), F atomic ratio are 1: 7.Then, be 25% ammoniacal liquor in above-mentioned mixed solution and dripping mass concentration, regulator solution pH value to 8.0.Mixing solutions placed 60 ℃ water-bath reacting by heating 2 hours.Solution centrifugal, washing, oven dry that reaction is obtained obtain green Ni (OH) ₂Powder.

Scanning electron microscope characterizes all flower-shaped spherical granules of sample, and median size is about 600nm, and petal thickness is 30nm, and width is 150nm, and petal presents more closely to be arranged.Through X-ray diffraction proof gained green powder is α-Ni (OH) ₂Crystal formation.The BET specific surface area is 92.13m ²/ g, productive rate are 64.7%.

Example 8 is with a certain amount of solid Ni (NO ₃) ₂6H ₂O is dissolved in the 100ml distilled water, obtains green Ni (NO ₃) ₂The aqueous solution.Wherein, Ni (II) volumetric molar concentration is 0.1mol/L in the solution.At Ni (NO ₃) ₂The adding mass concentration is 40% hydrofluoric acid in the aqueous solution, and Ni in the regulator solution (II) is 1: 3 with the F atomic ratio.Then, be 25% ammoniacal liquor in above-mentioned mixed solution and dripping mass concentration, regulator solution pH value to 8.3.Mixing solutions placed 60 ℃ water-bath reacting by heating 2 hours.Solution centrifugal, washing, oven dry that reaction is obtained obtain green Ni (OH) ₂Powder.

Scanning electron microscope characterizes all flower-shaped spherical granules of sample, and median size is about 1000nm, and petal thickness is 40nm, and width is 210nm, and petal presents more closely to be arranged.Through X-ray diffraction proof gained green powder is α/β-Ni (OH) ₂Mix crystal formation.The BET specific surface area is 78.57m ²/ g, productive rate are 62.4%.

Example 9 is with a certain amount of solid NiSO ₄7H ₂O is dissolved in the 100ml distilled water, obtains green NiSO ₄The aqueous solution.Wherein, Ni (II) volumetric molar concentration is 0.01mol/L in the solution.At NiSO ₄The adding mass concentration is 40% hydrofluoric acid in the aqueous solution, and Ni in the regulator solution (II) is 1: 3 with the F atomic ratio.Then, be 25% ammoniacal liquor in above-mentioned mixed solution and dripping mass concentration, regulator solution pH value to 8.3.Mixing solutions placed 60 ℃ water-bath reacting by heating 2 hours.Solution centrifugal, washing, oven dry that reaction is obtained obtain green Ni (OH) ₂Powder.

Scanning electron microscope characterizes all flower-shaped spherical granules of sample, and median size is about 500nm, and petal thickness is 20nm, and width is 110nm, and petal presents more closely to be arranged.Through X-ray diffraction proof gained green powder is α/β-Ni (OH) ₂Mix crystal formation.The BET specific surface area is 109.43m ²/ g, productive rate are 80.1%.

Claims (1)

1, a kind of sub-micrometer flower-shape Ni (OH) ₂The preparation method, it is characterized in that step is as follows:

1) is made into the solution that concentration is 0.01～0.1mol/L with the solid divalent nickel salt is soluble in water;

2) hydrofluoric acid is added obtain mixing solutions in the nickel salt solution, F and Ni (II) atomic ratio is between 1: 1～7: 1 in the solution;

3) in above-mentioned mixing solutions slowly the pH value of dropping ammonia regulator solution between 7.5～8.8;

4) will regulate solution after the pH value and put into 50 ℃～80 ℃ water-bath reacting by heating 2～4 hours;

5) precipitate and separate, collection, washing, drying are obtained green Ni (OH) ₂Powder.

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