WO2021109853A1

WO2021109853A1 - Cadmium hydride porous material, preparation method for same, and negative electrode and battery comprising same

Info

Publication number: WO2021109853A1
Application number: PCT/CN2020/129158
Authority: WO
Inventors: 吴昊; 张阳阳; 李江宇
Original assignee: 中国科学院深圳先进技术研究院
Priority date: 2019-12-03
Filing date: 2020-11-16
Publication date: 2021-06-10
Also published as: CN112897573A; CN112897573B

Abstract

The present invention relates to a cadmium hydride porous material, a preparation method for same, and a negative electrode and a battery comprising same. The pore diameter of the cadmium hydride porous material is greater than or equal to 0.2 µm, and the optical band gap is greater than or equal to 3.2 eV. The preparation method comprises the following steps: preparing a polar alkaline solution; preparing a non-polar cadmium source solution, the non-polar cadmium source solution comprising a non-polar solvent and an organic cadmium salt dissolved in the non-polar solvent, and the organic cadmium salt having a carbon chain length of 4-30; mixing and stirring the polar alkaline solution and the non-polar cadmium source solution, the mixing volume ratio of the polar alkaline solution to the non-polar cadmium source solution being n:1, n being equal to 0.1-100; continuing stirring the resulting mixture to maintain the non-polar cadmium source solution dispersed in the polar alkaline solution to generate cadmium hydroxide material precipitate; and performing solid-liquid separation and washing on the resulting mixture to prepare the cadmium hydride porous material. Porous cadmium hydride has great potential as a negative electrode material of a battery.

Description

Cadmium hydroxide porous material, preparation method, cathode and battery containing cadmium hydroxide porous material

Technical field

The invention relates to a cadmium hydroxide material, in particular a cadmium hydroxide porous material, a preparation method, and a cathode and a battery containing the cadmium hydroxide porous material.

Background technique

A porous electrode is an electrode composed of a powdered active material with a high specific surface or mixed with conductive inert solid particles and formed by pressing, sintering, or chemical conversion. The chemical power supply series all use porous electrodes. The use of porous electrodes greatly improves the activity of electrochemical reactions compared to the surface. Due to the increase in the amount of active material participating in the discharge process, and the increase in the porosity and specific surface of the electrode, the true current density of the electrode is greatly reduced, so that the energy loss (including voltage loss and capacity loss) of the battery is greatly reduced. , The performance of the battery has been significantly improved.

Cadmium hydroxide is an indirect bandgap semiconductor material with a wide band gap (3.2eV) with a layered structure. It can be used as a cathode material for cadmium-nickel batteries. It has a long life, high mechanical strength, and a wide operating temperature range (-40～+ 50℃), stable voltage, safe and reliable, convenient maintenance, can withstand high current several times or even ten times higher than the normal current, etc., are widely used in various equipment.

The existing cadmium hydroxide is mainly nanowires and nano flake cadmium hydroxide. For example, the preparation method of cadmium hydroxide nanowires published by Chinese invention patent CN102502786A on June 20, 2012 uses a mixed solution of benzene and cadmium nitrate to react with sodium hydroxide. Hydroxide can be obtained on the surface of a pure copper sheet cleaned with acetone. Cadmium nanowires; Another example is a simple method for preparing hexagonal CdO/CdS heterojunction nanocomposites, which was announced by Chinese invention patent CN107051548A on August 18, 2017. The lithium hydroxide aqueous solution was added dropwise to the stirring In the ethanol solution of cadmium nitrate, the final molar ratio is 2.4～2.6:1, continue to stir for 50～60min, then stand at 26～29℃ for 5～6h, transfer to the reactor, and react at 180～200℃ for 10 ~12h; the obtained product is washed and dried to obtain hexagonal cadmium hydroxide nanosheets. And the Chinese invention patent CN101306833B discloses a microwave preparation method of cadmium hydroxide nanomaterials. The cadmium salt is first dissolved in water, ammonia or sodium hydroxide is added to form a clear and transparent cadmium complex ion solution, and then water-insoluble fat is added. Alcohol, the fatty alcohol-water interface system is used as the reaction medium, microwave irradiation technology is used to control the microwave power and reaction time, and surfactants are added to change the size and morphology of the product to prepare cadmium hydroxide nanomaterials, hydrogen The cadmium oxide nanomaterial has a polycrystalline one-dimensional necklace-like structure, and is assembled from the secondary structure of hollow spheres.

With the development of society, electronic products have higher and higher requirements for batteries, and they also pose greater challenges to electrode materials, especially some special scenes are more prominent, currently composed of nanowires, nanosheets and hollow spheres The one-dimensional necklace-shaped cadmium hydroxide still cannot meet the increasing requirements of porous electrodes.

technical problem

The first object of the present invention is to provide a porous cadmium hydroxide material with a pore diameter greater than or equal to 0.2 μm, which can better meet the requirements of porous electrodes.

The second objective of the present invention is to provide a method for preparing cadmium hydroxide porous material. The preparation method is simple, fast, and efficient. It not only prepares porous cadmium hydroxide, but also saves time, energy, low cost of preparation and easy large-scale industrialization. Characteristics of production.

The third objective of the present invention is to provide a battery cathode, which contains a porous cadmium hydroxide material, and the performance of the battery is significantly improved.

The fourth object of the present invention is to provide a battery, the cathode of the battery contains cadmium hydroxide porous material, and the performance of the battery is significantly improved.

Technical solutions

The first objective of the present invention is achieved through the following technical solutions: a cadmium hydroxide porous material, the pore diameter is greater than or equal to 0.2 μm, and the optical band gap is greater than or equal to 3.2 eV.

The porous cadmium hydroxide material has a pore structure, which fills the gap that there is no report about porous cadmium hydroxide. Compared with nanowire and nanosheet cadmium hydroxide, porous cadmium hydroxide is used as a cadmium nickel battery. The cathode material has greater potential. The cadmium hydroxide porous material prepared by the present invention has pores, and the pore diameter is greater than or equal to 0.2 μm, and the optical band gap is greater than or equal to 3.2 eV. It is used to make electrodes. The porosity and specific surface area of the electrode The increase of, the true current density of the electrode is greatly reduced, so that the energy loss (including voltage loss and capacity loss) of the battery is greatly reduced, and the performance of the battery is significantly improved.

The present invention is further configured as follows: the cadmium hydroxide porous material includes crystals with a hexagonal crystal system, the pore diameter ranges from 0.2 to 1.5 μm, and the optical band gap ranges from 3.5 to 3.8 eV.

Preferably, the pore diameter ranges from 0.3 to 1.0 μm.

By controlling the size of the hole diameter, the requirements of the electrode can be better met.

The second objective of the present invention is achieved through the following technical solutions: a preparation method of cadmium hydroxide porous material, including the following steps:

Prepare a polar alkaline solution; the polar alkaline solution contains a polar solvent and a soluble base dissolved in the polar solvent;

Prepare a non-polar cadmium source solution; the non-polar cadmium source solution contains a non-polar solvent and an organic cadmium salt dissolved in the non-polar solvent, wherein the organic cadmium salt has a carbon chain length of 4-30;

Mix and stir the polar alkaline solution and the non-polar cadmium source solution, where the mixing volume ratio of the polar alkaline solution to the non-polar cadmium source solution is n:1, n=0.1-100; The non-polar cadmium source solution is maintained to be dispersed in the polar alkaline solution, and the polar alkaline solution and the non-polar cadmium source solution are immiscible, and the cadmium ions of the organic cadmium salt of the non-polar cadmium source solution are located in the non-polar cadmium source solution. The fluctuating interface between the solvent and the polar solvent moves to the fluctuating interface with the hydroxide ions enriched in soluble alkali to generate cadmium hydroxide material precipitate;

Solid-liquid separation and washing are performed on the obtained mixture to prepare a cadmium hydroxide porous material; the prepared cadmium hydroxide porous material has a pore diameter greater than or equal to 0.2 μm.

By adopting the above-mentioned basic technical scheme, the two-phase solution is used to dissolve soluble alkali and organic cadmium salt for immiscible mixing and stirring. The cadmium ion is located at the fluctuating interface between the non-polar solvent and the polar solvent to enrich the soluble alkali. The hydroxide ions move to the wave interface, and the two-phase wave interface is conducive to the reaction to generate nano-particle cadmium sulfide material, and the pore diameter of the cadmium hydroxide porous material is greater than or equal to 0.2 μm. The cadmium hydroxide porous material with specific pore diameter can be produced at low cost by pure wet chemical method. In addition, the appropriate volume ratio of solution mixing is one of the key factors for the preparation of cadmium hydroxide porous materials. The preparation method is simple, rapid and efficient, and not only the porous cadmium hydroxide is prepared; it also has the characteristics of time-saving, energy-saving and easy large-scale industrial production.

The present invention is further configured as follows: the soluble base has a first concentration in the polar solvent, the organic cadmium salt has a second concentration in the non-polar cadmium source solution, and the first concentration is greater than the second concentration; The volume of the medium polar alkaline solution is greater than the volume of the non-polar cadmium source solution, so that the dispersed non-polar cadmium source solution is coated in the polar alkaline solution.

By adopting the above-mentioned preferred technical solution, the first concentration is greater than the second concentration and the volume of the polar alkaline solution is greater than the volume of the non-polar cadmium source solution in terms of volume, so as to provide a structure that is like oil-in-water during mixing and stirring. , The hydroxide ions in the polar alkaline solution are more than the amount of hydroxide ions required by the cadmium source in the non-polar cadmium source solution, that is, the molar ratio of hydroxide ions in the resulting mixture is greater than the molar ratio of cadmium to ensure that the The fluctuating interface produces a wet chemical reaction and the cadmium hydroxide material produced is a porous material. The cadmium hydroxide material is more likely to be disconnected from the organic carbon base of the non-polar cadmium source solution and form nanoparticles that are insoluble in the polar alkaline solution. .

The present invention is further configured as follows: the first concentration is 1-30×10 ^{-7 kg} /m ³ , and the second concentration is ^{3-40×10 -7 kg} /m ³ .

By adopting the above-mentioned preferred technical solution, using the range limitation of the first concentration and the second concentration, the amount of hydroxide ions in the polar alkaline solution is more than that required by the cadmium source in the non-polar cadmium source solution. , Can further reduce the solubility of cadmium hydroxide material in the polar sulfur source solution, and is of great significance for regulating the morphology of the product.

The present invention is further configured that: the organic cadmium salt of the non-polar cadmium source solution contains fatty acid cadmium salt, and the number of fatty acid cadmium unsaturated bonds is 0-28.

By adopting the above-mentioned preferred technical solutions, the materials using organic cadmium salts include fatty acid cadmium salts with limited number of unsaturated bonds, so that the organic cadmium salt is attached to the two-phase wave interface during mixing and stirring, which not only makes the source of fatty acid cadmium more abundant It also makes the preparation process easier to implement and flexible.

The present invention is further configured to: in the process of mixing and stirring the polar alkaline solution and the non-polar cadmium source solution, the continuous stirring time is 1 to 24 hours, and in the process of solid-liquid separation and washing of the obtained mixture, the solid-liquid The separation method adopts one or more of centrifugal separation, filtration separation or suction filtration separation, and the washing method includes using water or/and alcohol to clean the solids obtained after separation for 2 to 5 times.

By adopting the above-mentioned preferred technical solution, the limitation of the continuous stirring time range, the specific solid-liquid separation method and the specific washing method is used to make the reaction more complete and obtain high-purity cadmium hydroxide porous material, which is suitable for the flexible selection of suitable industrial-scale production. the way.

The present invention is further configured as: the soluble base is selected from one or more of the combination of sodium hydroxide, potassium hydroxide, and ammonia;

The organic cadmium salt is selected from cadmium oleate, cadmium eductate, cadmium stearate, cadmium palmitoleate, cadmium arachidonic acid, cadmium eicosapentaenoate, cadmium docosapentaenoate and One or more of the combinations of cadmium laurate;

The non-polar solvent is selected from one or more of a combination of toluene and its homologues, acetone and its homologues, chloroform and its analogues, and n-hexane;

The polar solvent is selected from one or more of the combination of water and amides.

Choosing the above-mentioned soluble alkalis, organic cadmium salts, non-polar solvents and polar solvents can not only produce the required products, but also the raw materials are common industrial raw materials, which are easy to obtain, cheap and environmentally friendly, and are easier for large-scale industry. produce.

The present invention is further provided that: the organic cadmium salt has a hydrophobic group and is located inside the non-polar cadmium source solution near the wave interface during mixing and stirring; and the organic cadmium salt also has a hydrophilic group, which is And it is located at the wave interface during stirring.

By adopting the above-mentioned preferred technical solution, using the hydrophobic group and hydrophilic group of the organic cadmium salt, the organic cadmium salt can be attached to the fluctuating interface in a similar oil-in-water structure during the mixing and stirring process, so as to facilitate the oxidation of water. Cadmium porous material is formed by wet chemical reaction.

The third objective of the present invention is achieved through the following technical solutions: a battery cathode comprising the cadmium hydroxide porous material described in the above-mentioned scheme; or the preparation method comprising the cadmium hydroxide porous material described in the above-mentioned scheme The porous cadmium hydroxide material.

Cadmium hydroxide porous material is used to make electrodes. The increase in the porosity and specific surface of the electrode greatly reduces the true current density of the electrode, thereby greatly reducing the energy loss (including voltage loss and capacity loss) of the battery, and the performance of the battery Obtained a significant improvement.

The fourth objective of the present invention is achieved through the following technical solutions: a battery including the battery cathode described in the foregoing solution.

Beneficial effect

In summary, the present invention includes at least one of the following beneficial technical effects:

1. The porous cadmium hydroxide material has a pore structure, which fills the gap that there is no report about porous cadmium hydroxide. Compared with nanowire-shaped and nano-sheet-shaped cadmium hydroxide, porous cadmium hydroxide is used as cadmium and nickel. The cathode material of the battery has greater potential. The porous cadmium hydroxide material prepared by the present invention has pores, and the pore diameter is greater than or equal to 0.2 μm, and the optical band gap is greater than or equal to 3.2 eV. The increase in the specific surface area greatly reduces the true current density of the electrode, thereby greatly reducing the energy loss (including voltage loss and capacity loss) of the battery, and significantly improving the performance of the battery.

2. Use the two-phase solution to dissolve soluble alkali and organic cadmium salt for immiscible mixing and stirring. The cadmium ion is located at the fluctuating interface between the non-polar solvent and the polar solvent to enrich the hydroxide ions of the soluble alkali. The wave interface moves, and the two-phase wave interface is conducive to the reaction to generate nano-particle cadmium sulfide material, and the pore diameter of the cadmium hydroxide porous material is greater than or equal to 0.2 μm. The cadmium hydroxide porous material with specific pore diameter can be produced at low cost by pure wet chemical method. In addition, the appropriate volume ratio of solution mixing is one of the key factors for the preparation of cadmium hydroxide porous materials. The preparation method is simple, rapid and efficient, and not only the porous cadmium hydroxide is prepared; it also has the characteristics of time-saving, energy-saving and easy large-scale industrial production.

3. Utilize the limitation of continuous stirring time range, specific solid-liquid separation method and specific washing method to make the reaction more complete and obtain high-purity cadmium hydroxide porous material, which is suitable for flexible selection of suitable methods in industrial scale production.

4. By optimizing soluble bases, organic cadmium salts, non-polar solvents and polar solvents, not only can the desired products be prepared, but the raw materials are all common industrial raw materials, which are easy to obtain, cheap, green and environmentally friendly, and easier to scale. Large-scale industrial production.

5. Utilizing the hydrophobic and hydrophilic groups of the organic cadmium salt, the organic cadmium salt can adhere to the fluctuating interface in a similar oil-in-water structure during the mixing and stirring process to facilitate the wetness of the cadmium hydroxide porous material. Chemical reaction generated.

Description of the drawings

Figure 1 is a flow chart of a method for preparing cadmium hydroxide porous material in a preferred embodiment of the present invention;

2 is the X-ray diffraction (XRD) pattern of the cadmium hydroxide porous material prepared in Test Example 1 and the standard PDF card pattern of the pure hexagonal cadmium hydroxide JCPDS 31-0228;

Figure 3 is a scanning electron microscope (SEM) image of the cadmium hydroxide porous material prepared in Experimental Example 1;

Figure 4 is one of the results of characterization of the cadmium hydroxide porous material prepared in Experimental Example 1 using X-ray photoelectron spectroscopy (XPS);

Fig. 5 is one of the results of characterization of the target product cadmium hydroxide porous material prepared in Test Example 1 using an ultraviolet-visible spectrophotometer. Among them, Fig. 4a is the light absorption curve of the target product and its smoothed curve; Fig. 4b shows that the optical band gap of the target product is 3.7 eV by calculation using the smoothed curve.

Embodiments of the present invention

In order to understand the technical solution of the present invention more conveniently, the preparation method of the cadmium hydroxide porous material of the present invention will be described in further detail below, but it is not as the protection scope defined by the present invention.

The first embodiment of the present invention discloses a cadmium hydroxide porous material, the pore diameter is greater than or equal to 0.2 μm, and the optical band gap is greater than or equal to 3.2 eV. Preferably, the cadmium hydroxide porous material includes crystals with a hexagonal crystal system, the pore diameter ranges from 0.2 to 1.5 μm, and the optical band gap ranges from 3.5 to 3.8 eV. Preferably, the pore diameter ranges from 0.3 to 1.0 μm.

The second embodiment of the present invention discloses a preparation method of a cadmium hydroxide porous material, as shown in FIG. 1, including the following steps:

S1. Prepare a polar alkaline solution; the polar alkaline solution includes a polar solvent and a soluble base dissolved in the polar solvent;

S2. Mix and stir the polar alkaline solution and the non-polar cadmium source solution, where the mixing volume ratio of the polar alkaline solution and the non-polar cadmium source solution is n:1, n=0.1-100; keep stirring the resulting mixture The non-polar cadmium source solution is maintained to be dispersed in the polar alkaline solution, and the polar alkaline solution and the non-polar cadmium source solution are immiscible, and the cadmium ions of the organic cadmium salt of the non-polar cadmium source solution are located in the non-polar cadmium source solution. The fluctuating interface between the polar solvent and the polar solvent moves to the fluctuating interface with the hydroxide ions enriched in soluble alkali to generate cadmium hydroxide material precipitate;

S3, performing solid-liquid separation and washing on the obtained mixture to prepare a cadmium hydroxide porous material; the pore diameter of the prepared cadmium hydroxide porous material is greater than or equal to 0.2 μm.

The implementation principle of this embodiment is: the two-phase solution is used to dissolve soluble alkali and organic cadmium salt for immiscible mixing and stirring, and cadmium ions are located at the fluctuating interface between the non-polar solvent and the polar solvent to enrich the soluble alkali The hydroxide ion moves to the wave interface, and the two-phase wave interface is conducive to the reaction to generate nano-particle cadmium sulfide material, and the pore diameter of the cadmium hydroxide porous material is greater than or equal to 0.2 μm. The cadmium hydroxide porous material with specific pore diameter can be produced at low cost by pure wet chemical method. In addition, the appropriate volume ratio of solution mixing is one of the key factors for the preparation of cadmium hydroxide porous materials.

Regarding step S1, the soluble base has a first concentration in the polar solvent, and the organic cadmium salt has a second concentration in the non-polar cadmium source solution, and the first concentration is greater than the second concentration; during mixing and stirring The volume of the polar alkaline solution is greater than the volume of the non-polar cadmium source solution, so that the dispersed non-polar cadmium source solution is coated in the polar alkaline solution. Using the first concentration greater than the second concentration and the volume of the polar alkaline solution is greater than the volume of the non-polar cadmium source solution in terms of volume, it provides a structure that is like oil-in-water during mixing and stirring. The polar alkaline solution is The hydroxide ion is more than the amount of hydroxide ion reaction required by the cadmium source in the non-polar cadmium source solution, that is, the molar ratio of hydroxide ions in the resulting mixture is greater than the molar ratio of cadmium to ensure that wet chemical generation can occur at the fluctuating interface The reacted and generated cadmium hydroxide material is a porous material, and the cadmium hydroxide material is more likely to be disconnected from the organic carbon group of the non-polar cadmium source solution and form nanoparticles that are insoluble in the polar alkaline solution. Further, the first concentration is 1-30×10 ^{-7 kg} /m ³ , and the second concentration is ^{3-40×10 -7 kg} /m ³ .

Regarding step S1, the organic cadmium salt of the non-polar cadmium source solution contains fatty acid cadmium salt, and the number of fatty acid cadmium unsaturated bonds is 0-28. The materials using organic cadmium salts include fatty acid cadmium salts with limited number of unsaturated bonds. The organic cadmium salt is attached to the two-phase wave interface during mixing and stirring, which not only makes the source of fatty acid cadmium more abundant, but also makes the preparation process easier to implement And flexible.

Further, the organic cadmium salt is selected from cadmium oleate, cadmium eductate, cadmium stearate, cadmium palmitoleate, cadmium arachidonic acid, cadmium eicosapentaenoate, cadmium docosapentaenoate One or more of the combination with cadmium laurate; the non-polar solvent is selected from one of the combination of toluene and its homologues, acetone and its homologues, chloroform and its analogues, n-hexane or Multiple; the soluble base is selected from one or more of the combination of sodium hydroxide, potassium hydroxide, and ammonia; the polar solvent is selected from one or more of the combination of water and amides. Choosing the above-mentioned soluble alkalis, organic cadmium salts, non-polar solvents and polar solvents can not only produce the required products, but also the raw materials are common industrial raw materials, which are easy to obtain, cheap and environmentally friendly, and are easier for large-scale industry. produce.

Regarding step S2, during the process of mixing and stirring the polar alkaline solution and the non-polar cadmium source solution, the stirring time is continued for 1 to 24 hours; regarding step S3, during the solid-liquid separation and washing process of the obtained mixture, The solid-liquid separation method adopts one or more of centrifugal separation, filtration separation, or suction filtration separation, and the washing method includes washing the separated solids with water or/and alcohol for 2 to 5 times. Utilizing the limitation of continuous stirring time range, specific solid-liquid separation method and specific washing method, the reaction is more complete, and high-purity cadmium hydroxide porous material is obtained, which is suitable for flexible selection of suitable methods in industrial scale production.

Regarding step S2, the organic cadmium salt has a hydrophobic group and is located inside the non-polar cadmium source solution near the wave interface during mixing and stirring; and, the organic cadmium salt also has a hydrophilic group, which is located at the wave interface during mixing and stirring . Using the hydrophobic group and hydrophilic group of the organic cadmium salt, the organic cadmium salt can be attached to the fluctuating interface in a similar oil-in-water structure during the mixing and stirring process to facilitate the wet chemical reaction of the cadmium hydroxide porous material generate.

The third embodiment of the present invention discloses a battery cathode, which comprises the cadmium hydroxide porous material described in the above solution; or the cadmium hydroxide porous material prepared by the method for preparing the cadmium hydroxide porous material described in the above solution.

The fourth embodiment of the present invention discloses a battery including the battery cathode described in the above solution.

The fifth embodiment of the present invention proposes a low-cost preparation method of cadmium hydroxide porous structure, including a wet chemical method, in particular, the main steps are as follows:

Step 1. Dissolve the soluble base in a polar solvent to prepare a polar alkaline solution _{with a concentration of c 1} _{, where c 1} =1-30×10 ^{-7 kg} /m ³ .

Step 2. Dissolve the fatty acid cadmium salt in a non-polar solvent to prepare a non-polar solution containing cadmium with a _{concentration of c 2} _{, where c 2} =3～40×10 ^-7kg /m ³ , the carbon chain length of the fatty acid cadmium It is 4-30, and the number of unsaturated bonds is 0-28.

Step 3. Take the polar alkaline solution prepared in step 1 and the non-polar cadmium salt solution prepared in step 2, and mix according to the volume ratio n:1, and stir for 1-24 hours, where n=0.1-100. Then, the obtained reaction solution containing precipitates is subjected to solid-liquid separation and washing treatments to obtain a porous structure of cadmium hydroxide.

As a new method for preparing porous cadmium hydroxide at low cost, its uniqueness lies in:

Dissolve the soluble base in a polar solvent to prepare a polar alkaline solution _{with a concentration of c 1} _{, where c 1} =1～30×10 ^-7kg /m ³ ; the unique soluble base concentration is important for adjusting the morphology of the product significance.

Fatty acid cadmium salt is selected as the source of cadmium, the carbon chain length of fatty acid cadmium is 4-30, and the number of unsaturated bonds is 0-28; fatty acid cadmium is one of the key factors to obtain porous cadmium hydroxide; the carbon chain length of fatty acid cadmium It is 4-30, and the number of unsaturated bonds is 0-28, which not only makes the source of fatty acid cadmium more abundant, but also makes the preparation process easier to implement and flexible.

Dissolve fatty acid cadmium salt in a non-polar solvent to prepare a non-polar cadmium-containing solution with a _{concentration of c 2} _{, where c 2} =3～40×10 ^-7kg /m ³ ; unique cadmium source concentration, for the control product The morphology is of great significance.

Mix the prepared polar alkaline solution with the non-polar cadmium salt solution according to the volume ratio n:1, and stir for 1-24 hours, where n=0.1-100; the appropriate solution ratio is for preparing porous cadmium hydroxide One of the key factors.

Solid-liquid separation is centrifugal separation, filtration separation or suction filtration separation; it is more suitable for industrial-scale production in flexible selection of appropriate methods.

Through this new preparation method, the unique effects achieved are:

First, the prepared target products were characterized by X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy. The results showed that the target product was porous cadmium hydroxide with a hexagonal crystal phase.

Second, the prepared target product was characterized by an ultraviolet-visible light spectrophotometer. From the results, it can be seen that the optical band gap of the target product is 3.7 eV, which is a typical wide band gap semiconductor.

Third, the preparation method is simple, fast, and efficient. It not only produces porous hexagonal cadmium hydroxide; it also has the characteristics of time-saving, energy-saving, green environmental protection, low preparation cost and easy large-scale industrial production: all raw materials are required Common raw materials for industrial production, that is, cadmium fatty acid and soluble alkali as raw materials are industrial grade, and the polar solvents and non-polar solvents used are also industrial grade, and they are both easy to obtain and cheap.

The following five test examples are combined with the drawings for specific description

As a cadmium source, a fatty acid cadmium with a carbon chain length of 4-30 and a number of unsaturated bonds of 0-28; a soluble base as a reactant; a polar solvent and a non-polar solvent for dissolving the reactant; for washing Product of alcohol. The above raw materials are all industrial grade.

The specific steps for the preparation of Test Example 1 are:

Test Example 1

The specific steps of preparation are:

Step 1. Dissolve a soluble base in a polar solvent to prepare a polar alkaline solution _{with a concentration of c 1} _{, where c 1} = 5×10 ^-7kg /m ³ , the polar solvent is water, and the soluble base is sodium hydroxide .

Step 2. Dissolve fatty acid cadmium salt in a non-polar solvent to prepare a non-polar solution containing cadmium with a _{concentration of c 2} _{, where c 2} =3×10 ^{-7 kg} /m ³ , fatty acid cadmium is cadmium oleate, and non-polar The polar solvent is toluene.

Step 3. Take the polar alkaline solution prepared in step 1 and the non-polar cadmium salt solution prepared in step 2, and mix according to the volume ratio n:1, where n=10, and stir for 2 hours. Then the obtained reaction solution containing precipitates is subjected to solid-liquid separation and washing treatments to obtain the porous structure of cadmium hydroxide. The solid-liquid separation is suction filtration separation, and the washing is the use of industrial alcohol to perform the separation of the solid product obtained after separation. Two times of cleaning, the porous structure of cadmium hydroxide can be obtained.

Test Example 2

The specific steps of preparation are:

Step 1. Dissolve the soluble base in a polar solvent to prepare a polar alkaline solution _{with a concentration of c 1} _{, where c 1} =12×10 ^-7kg /m ³ , the polar solvent is water, and the soluble base is potassium hydroxide .

Step 2. Dissolve fatty acid cadmium salt in a non-polar solvent to prepare a non-polar solution containing cadmium with a _{concentration of c 2} _{, where c 2} =16×10 ^-7kg /m ³ , fatty acid cadmium is cadmium stearate, The non-polar solvent is toluene.

Step 3. Take the polar alkaline solution prepared in step 1 and the non-polar cadmium salt solution prepared in step 2, and mix according to the volume ratio n:1, where n=5, and stir for 2 hours. Then the obtained reaction solution containing precipitates is subjected to solid-liquid separation and washing treatments to obtain the porous structure of cadmium hydroxide. The solid-liquid separation is suction filtration separation, and the washing is the use of industrial alcohol to perform the separation of the solid product obtained after separation. After two cleanings, a porous structure of cadmium hydroxide as shown in or similar to those shown in Figure 1, Figure 2 and Figure 3, and as shown by the curve in Figure 4 was obtained.

Test Example 3

The specific steps of preparation are:

Step 1. Dissolve the soluble base in a polar solvent to prepare a polar alkaline solution _{with a concentration of c 1} _{, where c 1} =18×10 ^-7kg /m ³ , the polar solvent is water, and the soluble base is sodium hydroxide .

Step 2. Dissolve fatty acid cadmium salt in a non-polar solvent to prepare a non-polar solution containing cadmium with a _{concentration of c 2} _{, where c 2} =27×10 ^-7kg /m ³ , fatty acid cadmium is cadmium oleate, and non-polar The polar solvent is chloroform.

Step 3. Take the polar alkaline solution prepared in step 1 and the non-polar cadmium salt solution prepared in step 2, and mix according to the volume ratio n:1, where n=10, and stir for 2 hours. Then the obtained reaction solution containing precipitates is subjected to solid-liquid separation and washing treatments to obtain the porous structure of cadmium hydroxide. The solid-liquid separation is suction filtration separation, and the washing is the use of industrial alcohol to perform the separation of the solid product obtained after separation. After two cleanings, a porous structure of cadmium hydroxide as shown in or similar to those shown in Figure 1, Figure 2 and Figure 3, and as shown by the curve in Figure 4 was obtained.

Test Example 4

The specific steps of preparation are:

Step 1. Dissolve a soluble base in a polar solvent to prepare a polar alkaline solution _{with a concentration of c 1} _{, where c 1} =21×10 ^{-7 kg} /m ³ , the polar solvent is water, and the soluble base is ammonia.

Step 2. Dissolve fatty acid cadmium salt in a non-polar solvent to prepare a non-polar cadmium solution with a _{concentration of c 2} _{, where c 2} =12×10 ^{-7 kg} /m ³ , fatty acid cadmium is cadmium palmitoleate, non-polar The polar solvent is acetone.

Step 3. Take the polar alkaline solution prepared in step 1 and the non-polar cadmium salt solution prepared in step 2, and mix according to the volume ratio n:1, where n=0.5, and stir for 10 hours. Then the reaction liquid containing the precipitate was separated by suction filtration, and the solid product obtained after separation was washed twice with industrial alcohol, and the obtained product was as shown in or similar to Figure 1, Figure 2 and Figure 3, and as shown in Figure The curve in 4 shows the porous structure of cadmium hydroxide.

Test Example 5

The specific steps of preparation are:

Step 1. Dissolve a soluble base in a polar solvent to prepare a polar alkaline solution _{with a concentration of c 1} _{, where c 1} =30×10 ^{-7 kg} /m ³ , the polar solvent is formamide, and the soluble base is ammonia.

Step 2. Dissolve fatty acid cadmium salt in a non-polar solvent to prepare a non-polar solution containing cadmium with a _{concentration of c 2} _{where c 2} =25×10 ^-7kg /m ³ , and the fatty acid cadmium is cadmium arachidonic acid , The non-polar solvent is n-hexane.

Step 3. Take the polar alkaline solution prepared in step 1 and the non-polar cadmium salt solution prepared in step 2, and mix according to the volume ratio n:1, where n=0.1, and stir for 20 hours. Then the obtained reaction solution containing precipitates is subjected to solid-liquid separation and washing treatments to obtain the porous structure of cadmium hydroxide. The solid-liquid separation is suction filtration separation, and the washing is the use of industrial alcohol to perform the separation of the solid product obtained after separation. 2 washes. The porous structure of cadmium hydroxide as shown in or similar to that shown in FIG. 1, FIG. 2 and FIG. 3, and as shown by the curve in FIG. 4 was obtained.

Then select the fatty acid cadmium with a carbon chain length of 4-30 and the number of unsaturated bonds 0-28, such as cadmium eicosapentaenoate, cadmium docosapentaenoate or cadmium laurate as the source of cadmium. , Fatty acid cadmium concentration c ₁ select 12×10 ^-7kg /m ³ , 25×10 ^-7kg /m ³ or 30×10 ^-7kg /m ³ , choose formamide as polar solvent, choose n-hexane as non-polar solvent, soluble Sodium hydroxide, potassium hydroxide or ammonia water is selected as alkali, n and 1~24 hours to take any value that meets the actual production and the requirements of this patent, repeat the above examples 1 to 5, and the same or similar to Figure 1 is obtained. 2 and 3, and the cadmium hydroxide porous structure shown by the curve in FIG. 4.

Performance Testing

It can be seen from the X-ray diffraction (XRD) pattern of Figure 2 that the position of the diffraction peak of the target product indicated by XRD is consistent with that of JCPDS 31-0228, indicating that the target product is pure hexagonal cadmium hydroxide.

It can be seen from the scanning electron microscope (SEM) image of Figure 3 that the target product is a porous material with a pore diameter of 0.3 to 1 μm.

Figure 4a is the XPS full scan spectrum of the target product. From the figure, it can be seen that the XPS peaks of Cd3d and O1s are stronger. The appearance of the XPS peak of C1s indicates that the target product indicates the presence of adsorbed carbon; Figure 4b shows the XPS results based on the sample surface The adsorption carbon peak position has been corrected (284.8eV). Figure 4c and Figure 4d show that the target product is an oxygen-containing divalent cadmium compound.

It can be seen from Figure 5 that the target product was characterized by an ultraviolet-visible spectrophotometer. Figure 5a shows the light absorption curve of the target product and its smoothed curve; Figure 5b shows the optical band of the target product obtained by calculation using the smoothed curve. The gap is 3.7 eV.

Obviously, those skilled in the art can make various changes and modifications to the target cadmium hydroxide porous material of the present invention and its preparation method without departing from the spirit and scope of the present invention. In this way, if these modifications and variations to the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these modifications and variations.

Claims

A cadmium hydroxide porous material is characterized in that the pore diameter is greater than or equal to 0.2 μm, and the optical band gap is greater than or equal to 3.2 eV.
The cadmium hydroxide porous material according to claim 1, wherein the cadmium hydroxide porous material comprises crystals having a hexagonal crystal system, the pore diameter ranges from 0.2 to 1.5 μm, and the optical band gap ranges from 3.5 to 3.8 eV.
Preferably, the pore diameter ranges from 0.3 to 1.0 μm.
A preparation method of cadmium hydroxide porous material is characterized in that it comprises the following steps:

Prepare a polar alkaline solution; the polar alkaline solution contains a polar solvent and a soluble base dissolved in the polar solvent;

Prepare a non-polar cadmium source solution; the non-polar cadmium source solution contains a non-polar solvent and an organic cadmium salt dissolved in the non-polar solvent, wherein the organic cadmium salt has a carbon chain length of 4-30;

Mix and stir the polar alkaline solution and the non-polar cadmium source solution, where the mixing volume ratio of the polar alkaline solution to the non-polar cadmium source solution is n:1, n=0.1-100; The non-polar cadmium source solution is maintained to be dispersed in the polar alkaline solution, and the polar alkaline solution and the non-polar cadmium source solution are immiscible, and the cadmium ions of the organic cadmium salt of the non-polar cadmium source solution are located in the non-polar cadmium source solution. The fluctuating interface between the solvent and the polar solvent moves to the fluctuating interface with the hydroxide ions enriched in soluble alkali to generate cadmium hydroxide material precipitate;

Solid-liquid separation and washing are performed on the obtained mixture to prepare a cadmium hydroxide porous material; the prepared cadmium hydroxide porous material has a pore diameter greater than or equal to 0.2 μm.
The method for preparing a cadmium hydroxide porous material according to claim 3, wherein the soluble alkali has a first concentration in a polar solvent, an organic cadmium salt has a second concentration in a non-polar cadmium source solution, and The first concentration is greater than the second concentration; the volume of the polar alkaline solution during mixing and stirring is greater than the volume of the non-polar cadmium source solution, so that the dispersed non-polar cadmium source solution is coated in the polar In alkaline solution.
The method for preparing a cadmium hydroxide porous material according to claim 4, wherein the first concentration is 1-30×10 -7 kg /m 3 , and the second concentration is 3-40×10 -7 kg /m 3 .
The method for preparing a cadmium hydroxide porous material according to claim 3, wherein the organic cadmium salt of the non-polar cadmium source solution contains fatty acid cadmium salt, and the number of fatty acid cadmium unsaturated bonds is 0-28.
The method for preparing a cadmium hydroxide porous material according to claim 3, characterized in that, in the process of mixing and stirring the polar alkaline solution and the non-polar cadmium source solution, the continuous stirring time is 1 to 24 hours, and in the process of mixing and stirring the polar alkaline solution and the non-polar cadmium source solution, During the solid-liquid separation and washing process of the obtained mixture, the solid-liquid separation method adopts one or more of centrifugal separation, filtration separation or suction filtration separation, and the washing method includes the use of water or/and alcohol to separate the solid-liquid separation. The objects are cleaned 2 to 5 times.
The method for preparing a cadmium hydroxide porous material according to claim 5, wherein the soluble alkali is selected from one or more of a combination of sodium hydroxide, potassium hydroxide, and ammonia;

The organic cadmium salt is selected from cadmium oleate, cadmium eductate, cadmium stearate, cadmium palmitoleate, cadmium arachidonic acid, cadmium eicosapentaenoate, cadmium docosapentaenoate and One or more of the combinations of cadmium laurate;

The non-polar solvent is selected from one or more of a combination of toluene and its homologues, acetone and its homologues, chloroform and its analogues, and n-hexane;

The polar solvent is selected from one or more of the combination of water and amides.
The method for preparing a cadmium hydroxide porous material according to any one of claims 3-8, wherein the organic cadmium salt has a hydrophobic group and is located in the non-polar cadmium source solution near the wave interface during mixing and stirring. And, the organic cadmium salt also has a hydrophilic group, which is located at the wave interface during mixing and stirring.
A battery cathode, characterized in that it contains the cadmium hydroxide porous material according to claim 1 or 2; or it contains the hydroxide produced by the method for preparing the cadmium hydroxide porous material according to any one of claims 3-9. Cadmium porous material.
A battery characterized by comprising the battery cathode according to claim 10.