Preparation method of high-density alpha-phase nickel hydroxide

Abstract

The invention discloses a preparation method of high-density alpha-phase nickel hydroxide, and solves the problems that the crystal phase of the existing alpha-phase nickel hydroxide is easy to transform, the density is low and the research and development period of the traditional process is long. The method comprises the following steps: mixing an ammonia water solution, deionized water, a NiSO solution, an Al (SO) solution and a NaOH solution to form a reaction system (wherein the molar ratio of Al < 3 + > to Ni < 2 + > is not lower than 0.195, the concentration of ammonia water is 0.233-0.3262 mol / L, and the concentration of NaOH is 0.73-0.94 mol / L), heating to 40-90 DEG C, stirring for 12-48 hours, aging for 12-48 hours, washing, drying and grinding to obtain a product. The process parameters are efficiently optimized through screening equipment comprising 20-50 reaction subunits and a mechanical arm feeding system, the product is of a pure alpha-phase structure, the apparent density reaches 1.071-1.159 g / cm < 3 >, the crystal phase stability is remarkably improved, and the research and development period is remarkably shortened compared with a traditional method.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery materials, in particular to a preparation method of high-density α-phase nickel hydroxide. BACKGROUND

[0002] Nickel hydroxide (Ni(OH)2) is the core positive material of nickel-based batteries (such as nickel-hydrogen batteries and nickel-cadmium batteries), and its crystal phase structure directly determines the key performance of the battery, such as specific capacity. Compared with the industry mainstream β-Ni(OH)2(theoretical specific capacity 289 mAh / g), α-Ni(OH)2has a higher interlayer spacing (favorable for proton transmission) and a theoretical specific capacity of more than 300 mAh / g, which is a key material for breaking through the energy density bottleneck of batteries and is considered as an ideal positive material for the next generation of high-performance batteries.

[0003] Although the theoretical performance of α-Ni(OH)2is better, the existing technology has not solved the key problems of its large-scale application, specifically as follows: 1. Crystal phase structure is unstable: The crystal structure of α-Ni(OH)2is easily affected by external conditions (such as pH, temperature, and impurity ions), and is prone to α→β phase transition during synthesis or charging and discharging, resulting in a sharp decrease in specific capacity (the decrease can be more than 20%), which seriously affects the cycle life of the battery.

[0004] 2. Difficulty in preparing high-density: The synthesis conditions of α-Ni(OH)2(such as metal ion ratio, alkali concentration, and aging time) are highly sensitive to its bulk density (a key indicator of battery volume energy density). Although existing technologies can prepare α-phase products, the bulk density is generally low, which cannot meet the demand for "high volume energy density" of high-end batteries.

[0005] 3. Low research and development efficiency: The process optimization of traditional α-Ni(OH)2relies on manual orthogonal experiments, which requires testing different combinations of parameters (such as Al3+ doping amount, ammonia concentration, and NaOH concentration) one by one, and the research and development period is as long as several weeks or even months, which cannot meet the market demand for "rapid iteration" of the new energy industry. SUMMARY

[0006] To solve the problems of easy phase conversion, low density, and long research and development period of existing α-phase nickel hydroxide, the purpose of the present application is to provide a preparation method of high-density α-phase nickel hydroxide.

[0007] The present application provides a preparation method of high-density α-phase nickel hydroxide, comprising the following steps: (1) mixing an ammonia solution, deionized water, a NiSO4solution, an Al2(SO4)3solution, and a NaOH solution to form a reaction system; (2) Start the heating and stirring devices, heat the reaction system to 40-90℃ and stir for 12-48 hours, then age for 12-48 hours to obtain the precipitate; (3) Wash the precipitate until the pH of the washing solution is 9-10, dry it and grind it to obtain high-density α-phase nickel hydroxide; In the reaction system: Al 3+ with Ni 2+ The molar ratio is not less than 0.195; the ammonia concentration is 0.233-0.3262 mol / L; the NaOH concentration is 0.73-0.94 mol / L; The high-density α-phase nickel hydroxide has a loose packing density of 1.071-1.159 g / cm³ and a pure α-phase crystal structure.

[0008] Al in the reaction system 3+ The content is not higher than 0.15 mol / L, and the pH value is 10-14.

[0009] The concentration of the NiSO4 solution is 1-2 mol / L, the concentration of the Al2(SO4)3 solution is 0.01-0.5 mol / L, the concentration of the NaOH solution is 5-10 mol / L, and the concentration of the ammonia solution is 6-14 mol / L.

[0010] Nickel hydroxide samples under different conditions were prepared in a screening device for high-density α-phase nickel hydroxide preparation conditions. The resulting nickel hydroxide samples were then subjected to crystal phase structure and loose packing density tests to screen and determine the preparation conditions corresponding to high-density α-phase nickel hydroxide. The screening device includes: The liquid storage unit has multiple independent storage spaces, which can respectively hold NiSO4 solution, Al2(SO4)3 solution, NaOH solution, ammonia water, and deionized water. The liquid storage unit includes, but is not limited to, a liquid storage tank. The reaction unit is equipped with a heating device, a stirring device, and 20-50 reaction sub-units, wherein the reaction sub-units are reaction cells; The feeding unit includes multiple liquid feeding lines, each line equipped with a metering pump and connected to at least one liquid storage unit. The feeding unit is a feeding robotic arm. The metering pump is electrically connected to a control terminal to precisely control the amount of reaction solution added. The metering pump includes, but is not limited to, a peristaltic pump. The reaction solution from the storage unit is added to the reaction subunit of the reaction unit by controlling the feeding unit. The heating and stirring devices are then activated for heating, stirring, and aging. The resulting precipitate is washed, dried, and ground to obtain a nickel hydroxide sample. Finally, the crystal phase structure and bulk density of the nickel hydroxide sample are measured. Based on the measurement results, the preparation conditions corresponding to the high-density α-phase nickel hydroxide sample are selected. Nickel hydroxide samples prepared under the following conditions are obtained through screening: The ammonia concentration in the reaction system is 0.0466 mol / L, Al 3+ with Ni 2+ When the molar ratio of NaOH to Fe is not less than 0.18 and the concentration of NaOH is not less than 1.45 mol / L, pure α-phase nickel hydroxide is obtained.

[0011] Al in the reaction system 3+ with Ni 2+ When the molar ratio is 0.195, the NaOH concentration is 1.33 mol / L, and the ammonia concentration is between 0.2097 and 0.3961 mol / L, the loose packing density of the α-phase nickel hydroxide is between 1.05 and 1.159 g / cm³. 3 .

[0012] Al in the reaction system 3+ with Ni 2+ When the molar ratio is 0.195, the ammonia concentration is 0.233 mol / L, and the NaOH concentration is 0.73-0.94 mol / L, the loose pack density of the α-phase nickel hydroxide powder is 1.05-1.13 g / cm³. 3 .

[0013] Al in the reaction system 3+ with Ni 2+ The molar ratio is not less than 0.195, the NaOH concentration is 0.8 mol / L, the ammonia concentration is 0.233-0.3262 mol / L, and the α-phase nickel hydroxide has a pure α-phase crystal structure with a loose packing density of 1.071-1.159 g / cm³. 3 Under these conditions, pure α-phase high-density nickel hydroxide was prepared. This invention utilizes a screening device to obtain the preparation conditions for high-density α-phase nickel hydroxide, avoiding interference from traditional artificial synthesis, significantly shortening the research and development cycle, and enabling rapid and accurate screening of key preparation conditions.

[0014] The beneficial effects of this invention are: (1) Stability and high density of pure α-phase structure: By precisely controlling the molar ratio of Al³⁺ to Ni²⁺ and the reaction system parameters, the stable preparation of pure α-phase crystal structure was achieved, overcoming the defect of easy transformation of α-phase to β-phase in the prior art, and ensuring the high specific capacity characteristics of the material in charge-discharge cycles. The loose packing density of α-phase nickel hydroxide prepared by this invention reaches 1.071-1.159 g / cm³, which helps to improve the volumetric energy density in battery and other application scenarios.

[0015] (2) High-efficiency screening system: The screening equipment uses a parallel experimental design of 20-50 reaction sub-units, combined with robotic arm feeding and metering pump precise control, which significantly shortens the process parameter optimization cycle and improves efficiency significantly compared with traditional orthogonal experimental methods.

[0016] (3) Synergistic effect mechanism of components: utilizing Al 3+ The synergistic effect of doping with ammonia and NaOH concentrations not only stabilized the α-phase structure but also increased the material density by inhibiting excessive crystal growth. Detailed Implementation

[0017] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0018] The present invention provides a method for preparing high-density α-phase nickel hydroxide, comprising the following steps: (1) Mix ammonia solution, deionized water, NiSO4 solution, Al2(SO4)3 solution and NaOH solution to form a reaction system; (2) Start the heating and stirring devices, heat the reaction system to 40-90℃ and stir for 12-48 hours, then age for 12-48 hours to obtain the precipitate; (3) Wash the precipitate until the pH of the washing solution is 9-10, dry it and grind it to obtain high-density α-phase nickel hydroxide; Nickel hydroxide samples under different conditions were prepared in a high-density α-phase nickel hydroxide preparation condition screening device. The obtained nickel hydroxide samples were subjected to crystal phase structure and loose packing density tests to screen the preparation conditions corresponding to high-density α-phase nickel hydroxide. The device includes: a liquid storage unit with multiple independent liquid storage spaces; a reaction unit equipped with a heating device, a stirring device and multiple reaction sub-units; and a feeding unit including multiple liquid feeding lines, each of which is equipped with a metering pump and the feed end is connected to at least one liquid storage space. This equipment enables rapid screening of specific nickel hydroxide preparation conditions with accurate results. The screening method specifically includes: pre-prepared NiSO4 solution, Al2(SO4)3 solution, NaOH solution, ammonia water, and deionized water are respectively loaded into different storage spaces of the storage unit; the reaction solution from the storage unit is added to the reaction sub-unit of the reaction unit by controlling the feeding unit; the heating and stirring devices are started, and the mixture is heated, stirred, and aged; the resulting precipitate is washed, dried, and ground to obtain a nickel hydroxide sample; finally, the crystal phase structure and loose packing density of the nickel hydroxide sample are detected, and the preparation conditions corresponding to the high-density α-phase nickel hydroxide sample are screened based on the detection results.

[0019] The high-density α-phase nickel hydroxide described in this invention has a loose packing density of not less than 1.05 g / cm³. 3 Nickel hydroxide with a pure α-phase crystal structure.

[0020] This invention enables the screening of various preparation conditions during the preparation of nickel hydroxide. The selection of preparation conditions can be determined based on actual production needs. According to a preferred embodiment of this invention, different ratios of Al2(SO4)3 solution to NiSO4 solution and different amounts of NaOH solution are set in different reaction compartments to form aluminum doping gradients and NaOH concentration gradients, thus preparing different nickel hydroxide samples. Based on the crystal phase structure detection results of the samples, the Al phase structure corresponding to pure α is selected in a reaction system with an ammonia concentration of 0.0466 mol / L. 3+ with Ni 2+ The molar ratio of NaOH used should not be less than 0.18, and the concentration of NaOH should not be less than 1.45 mol / L.

[0021] This invention enables the screening of various preparation conditions during the preparation of nickel hydroxide. The selection of preparation conditions can be determined based on actual production needs. According to a preferred embodiment of this invention, by setting different amounts of ammonia added in different reaction cells to create different ammonia concentrations in the reaction solution, an ammonia concentration gradient is formed, resulting in the preparation of different nickel hydroxide samples. The desired nickel hydroxide sample is then selected based on the ammonia concentration in Al... 3+ with Ni 2+In a reaction system with a molar ratio of 0.195 and a NaOH concentration of 1.33 mol / L, the loose packing density of the sample powder was made to be 1.05-1.159 g / cm³. 3 The corresponding ammonia concentration is 0.2097-0.3961 mol / L.

[0022] This invention enables the screening of various preparation conditions during the preparation of nickel hydroxide. The selection of preparation conditions can be determined based on actual production needs. According to a preferred embodiment of this invention, by setting different amounts of NaOH solution added to different reaction cells to create different NaOH concentrations in the reaction solution, a NaOH concentration gradient is formed, resulting in the preparation of different nickel hydroxide samples. The selected samples are then screened for those that are suitable for use in Al... 3+ with Ni 2+ In a reaction system with a molar ratio of 0.195 and an ammonia concentration of 0.233 mol / L, the loose packing density of the sample powder was made to be 1.05-1.13 g / cm³. 3 The corresponding NaOH concentration is 0.73-0.94 mol / L.

[0023] This invention enables the screening of various preparation conditions during the preparation of nickel hydroxide. The selection of preparation conditions can be determined based on actual production needs. According to a preferred embodiment of this invention, by setting different ratios of Al2(SO4)3 solution to NiSO4 solution in different reaction compartments and different amounts of ammonia added, different ammonia concentrations in the reaction solution are formed, creating gradients in aluminum doping and ammonia concentration, thus obtaining different nickel hydroxide samples. The selected sample, in a reaction system with a NaOH concentration of 0.8 mol / L, simultaneously satisfies the requirements of a pure α-phase crystal structure and a bulk density of 1.071-1.159 g / cm³. 3 The corresponding Al 3+ with Ni 2+ The molar ratio of the dosage should not be less than 0.195, and the concentration of ammonia water should be 0.233-0.3262 mol / L.

[0024] The reaction system of this invention for Al 3+ There are no special requirements for the content of Al, but Al is preferred. 3+ The content should not exceed 0.15 mol / L; there are no special requirements for pH in the reaction system, but a pH of 10-14 is preferred.

[0025] The concentrations of NiSO4 solution, Al2(SO4)3, NaOH solution, and ammonia solution are not particularly limited in this invention. Preferably, the concentration of NiSO4 solution is 1-2 mol / L. Preferably, the concentration of Al2(SO4)3 solution is 0.01-0.5 mol / L. Preferably, the concentration of NaOH solution is 5-10 mol / L. Preferably, the concentration of ammonia solution is 6-14 mol / L.

[0026] In this invention, there are no special requirements for the heating temperature. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the heating temperature is 40-90°C.

[0027] In this invention, there are no special requirements for the heating time. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the heating time is 12-48 hours.

[0028] In this invention, there are no special requirements for the specific operation of heating and stirring. The conventional heating and stirring methods in the art can be referred to. For example, after the reaction base liquid is formed, the temperature is raised to the target temperature, the temperature is maintained and stirred for 10-30 minutes, and then the remaining solution is added and stirred for 36-60 hours to ensure that the reaction is fully carried out.

[0029] In this invention, there are no special requirements for the aging time. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the aging time is 12-48 hours.

[0030] In this invention, the washing, drying, and grinding processes are all operations well known to those skilled in the art and will not be described in detail here.

[0031] In this invention, the detection of crystal phase structure and loose packing density are operations well known to those skilled in the art and will not be described in detail here.

[0032] According to a preferred embodiment of the present invention, the feeding unit is configured as a feeding robotic arm, and the feeding robotic arm is equipped with multiple liquid feeding lines. The aforementioned technical solution enables a faster and more precise feeding process.

[0033] In this invention, there is no particular limitation on the specific arrangement of the reaction subunits. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the reaction subunits are configured as reaction lattices.

[0034] In this invention, there are no special requirements for the number of reaction subunits. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the number of reaction subunits is 20-50.

[0035] In this invention, there are no special requirements for the specific configuration of the liquid storage space; for example, it can be a liquid storage tank.

[0036] In this invention, the heating device can be any conventional heating device in the art. There are no special requirements for this. Alternatively, the reaction subunit, the heating device, and the stirring device can be combined, for example, a heated and stirred reactor.

[0037] In this invention, there are no special requirements for the specific configuration of the stirring device. For example, it can be a magnetic stirring device, or the reaction subunit, heating device and stirring device can be combined, such as a heated stirring reactor.

[0038] In this invention, there are no special requirements for the specific type of metering pump, such as a peristaltic pump.

[0039] According to a preferred embodiment of the present invention, the metering pump is electrically connected to the control terminal. Using the aforementioned technical solution, the amount of reaction solution added can be precisely controlled.

[0040] The optimal heating temperature is 40-60℃, the optimal heating time is 40-48h, and the optimal aging time is 12-15h, as determined by the aforementioned method of this invention. The following examples are all screened under other specific conditions under the aforementioned optimal conditions.

[0041] The present invention will be described in detail below through embodiments.

[0042] In the following examples, the crystal phase structure of the nickel hydroxide sample was determined by X-ray diffraction. The bulk density of a nickel hydroxide sample is calculated by dividing its mass by its volume, using the formula: ρ 松装密度 =m Ni(OH)2 / V Ni(OH)2 ; In this embodiment of the invention, nickel hydroxide samples are all screened in a screening device, which includes a storage unit, a reaction unit, and a feeding unit. The storage unit includes five independent storage tanks, the reaction unit includes a multi-channel heated and stirred reactor with 42 reaction compartments, and the feeding unit includes a feeding robotic arm with five feeding pipelines. Each feeding pipeline is equipped with a peristaltic pump, and the feed port of each feeding pipeline is connected to a storage tank. The peristaltic pump is connected to a control terminal.

[0043] Example 1 Prepare NiSO4 solution with a concentration of 2 mol / L, Al2(SO4)3 solution with a concentration of 0.5 mol / L, NaOH solution with a concentration of 10 mol / L, ammonia solution with a concentration of 14 mol / L, and deionized water, and store them in 5 storage tanks for later use. The feeding robotic arm was moved above the 20 reaction cells respectively. The feeding amount was precisely controlled by the peristaltic pump. 1 mL of ammonia solution and 69 mL of deionized water were added to each reaction cell to form a reaction base liquid. The reaction base liquid was heated to 40°C and then maintained at the temperature while stirring for 10 min. The robotic arm was moved above each of the 20 reaction cells, and the corresponding volume of solution was added to each cell according to Table 1 under precise control of a peristaltic pump. After the addition was complete, the mixture was stirred continuously at 60°C for 48 hours, followed by aging for 12 hours. The aged precipitate was washed with pure water, with the pH of the washing solution controlled at 9. The washed precipitate was then dried in an oven for 8 hours, removed, and ground to obtain 20 nickel hydroxide samples. The crystal phase structures of each sample were obtained by XRD testing, as shown in Table 1. This indicates that in a reaction system with an ammonia concentration of 0.0466 mol / L, controlling the Al... 3+ with Ni 2+ The molar ratio of NaOH used is not less than 0.18, and the concentration of NaOH is not less than 1.45 mol / L, which enables the nickel hydroxide sample to have a pure α phase crystal structure. The actual operation time of this embodiment is about 65 hours, while the traditional manual operation is expected to take 200 hours, which greatly reduces the time cost. Example 2 Prepare NiSO4 solution with a concentration of 2 mol / L, Al2(SO4)3 solution with a concentration of 0.5 mol / L, NaOH solution with a concentration of 10 mol / L, ammonia solution with a concentration of 14 mol / L, and deionized water, and store them in 5 storage tanks for later use. The robotic arms were moved above the 20 reaction cells, and the feed rate was precisely controlled by a peristaltic pump, adding 70 mL of deionized water and 39 mL of Al2(SO4) to each reaction cell. 3、 100 mL of NiSO4 and 40 mL of NaOH are used to form a reaction base solution. The solution is heated to 60 °C and then maintained while stirring.

[0044] The robotic arm was moved above each of the 20 reaction cells, and the corresponding volume of solution was added to each cell according to Table 2 under precise control of a peristaltic pump. After the addition was complete, stirring was continued for 48 hours, followed by aging for 12 hours. The aged precipitate was washed with pure water, with the pH of the washing solution controlled at 9. The washed precipitate was then dried in an oven for 8 hours, removed, and ground to obtain 20 nickel hydroxide samples. The bulk density of each sample was calculated as shown in Table 2, indicating that in Al... 3+ with Ni 2+In a reaction system with a molar ratio of 0.195 and a NaOH concentration of 1.33 mol / L, controlling the ammonia concentration between 0.2097 and 0.3961 mol / L can result in a sample bulk density of 1.05–1.159 g / cm³. 3 The density is within the range required; the actual operation time of this embodiment is about 65 hours, while the traditional manual operation is expected to take 200 hours, which greatly reduces the time cost.

[0045] Example 3 Prepare NiSO4 solution with a concentration of 2 mol / L, Al2(SO4)3 solution with a concentration of 0.5 mol / L, NaOH solution with a concentration of 10 mol / L, ammonia solution with a concentration of 14 mol / L, and deionized water, and store them in 5 storage tanks for later use. The robotic arm was moved above each of the 20 reaction cells. The amount of material added was precisely controlled by the peristaltic pump. 70 mL of deionized water, 39 mL of Al2(SO4)3, 100 mL of NiSO4 and 5 mL of ammonia were added to each reaction cell to form a reaction base liquid. The reaction base liquid was heated to 60°C and then maintained at the temperature while being stirred. The robotic arm was moved above each of the 20 reaction cells, and the corresponding volume of NaOH solution was added to each cell according to Table 3 under precise control of a peristaltic pump. After the addition was complete, stirring was continued for 48 hours, followed by aging for 12 hours. The aged precipitate was washed with pure water, with the pH of the washing solution controlled at 9. The washed precipitate was then dried in an oven for 8 hours, removed, and ground to obtain 20 nickel hydroxide samples. The bulk density of each sample was calculated as shown in Table 3, indicating that in Al... 3+ with Ni 2+ In a reaction system with a molar ratio of 0.195 and an ammonia concentration of 0.233 mol / L, controlling the NaOH concentration to be 0.73-0.94 mol / L can maintain a sample bulk density of 1.05-1.13 g / cm³. 3 The density is within the range required; the actual operation time of this embodiment is about 65 hours, while the traditional manual operation is expected to take 200 hours, which greatly reduces the time cost.

[0046] Example 4 Prepare NiSO4 solution with a concentration of 2 mol / L, Al2(SO4)3 solution with a concentration of 0.5 mol / L, NaOH solution with a concentration of 10 mol / L, ammonia solution with a concentration of 14 mol / L, and deionized water, and store them in 5 storage tanks for later use. The robotic arm was moved above each of the 25 reaction cells. The amount of material added was precisely controlled by the peristaltic pump. 70 mL of deionized water, 100 mL of NiSO4 solution, and 24 mL of NaOH solution were added to each reaction cell to form a reaction base liquid. The reaction base liquid was heated to 40°C and then maintained at the temperature while being stirred. The robotic arm was moved above each of the 25 reaction cells, and the corresponding volume of solution was added to each cell according to the orthogonal array Table 4, precisely controlled by a peristaltic pump. Finally, deionized water was added to bring the reaction system to 300 mL. After addition, stirring was continued for 48 hours, followed by aging for 12 hours. The aged precipitate was washed with pure water, controlling the pH of the washing solution to 9. The washed precipitate was then dried in an oven for 8 hours, removed, and ground to obtain 25 nickel hydroxide samples. The crystal phase results of each sample were obtained by XRD testing, as shown in Table 4. The calculated bulk density of each sample is also shown in Table 4. This indicates that in a reaction system with a NaOH concentration of 0.8 mol / L, controlling the Al... 3+ with Ni 2+ When the molar ratio of the ammonia used is not less than 0.195, and the concentration of ammonia in the reaction solution is 0.233-0.3262 mol / L, the crystal structure of the sample can be made into a pure α phase with a loose packing density of 1.071-1.159 g / cm³. 3 It meets the requirements of both crystal phase structure and high density; the actual operation time of this embodiment is about 65 hours, while the traditional manual operation is expected to take 200 hours, which greatly reduces the time cost.

[0047] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for preparing high-density α-phase nickel hydroxide, characterized in that, Includes the following steps: (1) Mix ammonia solution, deionized water, NiSO4 solution, Al2(SO4)3 solution and NaOH solution to form a reaction system; In the reaction system: Al 3+ with Ni 2+ The molar ratio is not less than 0.195; the ammonia concentration is 0.233-0.3262 mol / L; the NaOH concentration is 0.73-0.94 mol / L; (2) Start the heating and stirring devices, heat the reaction system to 40-90℃ and stir for 12-48 hours, then age for 12-48 hours to obtain the precipitate; (3) Wash the precipitate until the pH of the washing solution is 9-10, dry it and grind it to obtain high-density α-phase nickel hydroxide; The high-density α-phase nickel hydroxide has a loose packing density of 1.071-1.159 g / cm³ and a pure α-phase crystal structure.

2. The method according to claim 1, characterized in that, Al in the reaction system 3+ Concentration ≤ 0.15 mol / L, pH value 10-14.

3. The method according to claim 1, characterized in that, The concentration of the NiSO4 solution is 1-2 mol / L, the concentration of the Al2(SO4)3 solution is 0.01-0.5 mol / L, the concentration of the NaOH solution is 5-10 mol / L, and the concentration of the ammonia solution is 6-14 mol / L.

4. The method according to claim 1, characterized in that, In step (2), the heating temperature is 40-60℃, the stirring time is 40-48 hours, and the aging time is 12-15 hours.

5. The method according to any one of claims 1-4, characterized in that, The preparation conditions for high-density α-phase nickel hydroxide were determined using the following screening equipment and methods: The device includes: a liquid storage unit with multiple independent liquid storage spaces, which respectively contain NiSO4 solution, Al2(SO4)3 solution, NaOH solution, ammonia water and deionized water; The reaction unit is equipped with a heating device, a stirring device, and 20-50 reaction sub-units, wherein the reaction sub-units are reaction cells; The feeding unit includes multiple liquid feeding pipelines, each pipeline is equipped with a metering pump and connected to a liquid storage unit. The feeding unit is a feeding robotic arm, and the metering pump is electrically connected to the control terminal. The reaction solution from the storage unit is added to the reaction subunit of the reaction unit by controlling the feeding unit. The heating and stirring devices are started, and the mixture is heated, stirred, and aged. The resulting precipitate is washed, dried, and ground to obtain a nickel hydroxide sample. The crystal phase structure and bulk density of the nickel hydroxide sample are detected, and the preparation conditions corresponding to high-density α-phase nickel hydroxide are selected based on the detection results.

6. A screening device for the preparation conditions of high-density α-phase nickel hydroxide, characterized in that, include: Storage unit: Multiple independent storage tanks, storing NiSO4 solution, Al2(SO4)3 solution, NaOH solution, ammonia water and deionized water respectively; Reaction unit: Multi-channel heated and stirred reactor, containing 20-50 reaction cells; Feeding unit: A robotic arm connects to 5 feeding pipelines, each pipeline is equipped with a peristaltic pump and connected to a storage tank, and the peristaltic pump is electrically connected to the control terminal.

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