CN1299370C - Method for coating and mixing metal M alpha-Co(OH)2 on ball shape nickel hydroxide surface - Google Patents

Abstract

The invention relates to a process for coating α-Co(OH) ₂ on the surface of spherical nickel hydroxide. The tap density of the prepared cobalt-coated spherical nickel hydroxide can reach about 2.2 g/cm ³ . The main content of the process is: use the method of controlled crystallization to coat a layer of doped one or more of Y, Al, Cr, Mn, Yb, Sc, La, In, Ti, Zn on the surface of spherical nickel hydroxide α-Co(OH) ₂ of metal M, this kind of coated spherical nickel hydroxide, when the (Co+M):Ni ratio (molar ratio) is 0.03 to 0.1, it can significantly improve the quality of spherical nickel hydroxide products. Conductivity, improve the performance of Ni(OH) ₂ electrodes, and then significantly improve the performance of the battery, such as increasing specific capacity and output power, improving charge/discharge cycle life and fast charging ability, improving overcharge/discharge resistance and shelf life, Increase the oxygen evolution overpotential, etc.

Description

Method of Coating α-Co(OH)2 Doped with Metal M on the Surface of Spherical Nickel Hydroxide

technical field

The invention belongs to the field of new chemical material preparation. Particularly relate to a kind of α-Co(OH) of coating doping metal M on spherical nickel hydroxide surface _2Methods

Background technique

Spherical nickel hydroxide is a positive electrode active material for alkaline rechargeable batteries such as nickel-hydrogen batteries. At present, nickel-hydrogen batteries have been widely used in electronics, communications and other fields, and have shown good application prospects in the field of electric vehicles. However, since Ni(OH) ₂ is a low-conductivity p-type semiconductor, the charge/discharge efficiency is low, the electrode performance is poor, and the capacity of the battery is reduced. In order to improve the utilization rate of the active material and its conductivity with the current collector, Generally, an appropriate amount of Ni powder, Co powder, CoO powder or Co(OH) ₂ powder is added to Ni(OH) ₂ as a conductive agent when making an electrode. During the charging process, these substances will be oxidized to highly conductive CoOOH, which is Ni (OH) ₂ provides good electrical conductivity between particles and between particles and current collectors. The process currently used is the mixed addition method.

The cobalt or cobalt compound added in a mixed manner, in the electrochemical process or alkali treatment process, undergoes a dissolution-redeposition process, and is partially redeposited on the surface of the spherical nickel or on the current collector to form a conductive network. However, limited by the mixing process conditions and the characteristics of the material itself, the mixing of the active material and the conductive agent cannot be very uniform. The deposition layer formed by this process has unsatisfactory uniformity and deposition rate, and cannot effectively reduce the Ni(OH) _2. The contact resistance between the particles and between the particles and the current collector, so that the performance of the electrode cannot be greatly improved; in addition, the cavity left by the dissolution of the cobalt compound has not been fully utilized, thus limiting the active material. The filling amount reduces the specific capacity of the battery.

In addition, a porous film of metal nickel or metal cobalt can be plated on the surface of the spherical nickel hydroxide by electroless plating. However, the plated nickel film will be gradually oxidized to Ni(OH) ₂ during the charge and discharge process to participate in the charge and discharge process of the battery, and the conductive network formed by the conductive nickel film will be destroyed, resulting in a sharp decline in battery performance; and The deposited cobalt film generates Co(OH) ₂ and finally converts to highly conductive CoOOH. However, from the perspective of the electroless plating process, its operating conditions are very harsh, and precious metals need to be used as catalysts, resulting in increased product costs and environmental pollution. Therefore, this process is limited in industrial production.

It is also possible to coat β-Co(OH) ₂ on the surface of spherical nickel hydroxide by chemical methods, but the activation speed of the coated β-Co(OH) ₂ is slow, and it must be oxidized to high conductivity before use. CoOOH, but the oxidation process is more complicated. The present invention has developed a high-density coated α-Co(OH) ₂ spherical Ni(OH) ₂ , the tap density of the product can reach 2.2g·cm ^-3 , and the coated α-Co(OH) ₂ can be easily oxidized to highly conductive CoOOH.

Contents of the invention

The object of the present invention is to provide a kind of α-Co(OH) of coating doping metal M on spherical nickel hydroxide surface _2Methods , it is characterized in that, this method comprises the following steps successively:

1. Prepare a cobalt salt aqueous solution with a concentration of 0.5 to 3 mol/liter;

2. Prepare an aqueous solution of metal salt to be doped with a concentration of 0.1 to 0.5 mol/liter;

3. Prepare an aqueous alkali solution with a concentration of 3 to 8 mol/liter;

4. Prepare a certain concentration of complexing agent aqueous solution;

5. Take a certain weight of spherical nickel hydroxide and 1 to 5 times the weight of ion-free water and place them in the reactor, and pump the above-mentioned cobalt salt solution, metal element M salt solution, alkali solution and complexing agent solution respectively Continuously input into a stirred reactor, control the flow of cobalt salt aqueous solution and complexing agent aqueous solution, that is, control the molar ratio of complexing agent to Co, adjust the flow of alkaline aqueous solution so that the pH of the reaction solution in the reactor is 8~ 11. Control the reaction temperature at 30-60°C, the molar ratio of the coated metal M and Co to the coated nickel hydroxide Ni is: (Co+M): Ni=0.03-0.1, the ratio of metal M and Co The molar ratio is 0.01～0.25, and the reaction is a batch reaction;

Six. The product obtained in step 5 is transferred to the solid-liquid separator for solid-liquid separation, and the solid product obtained by the solid-liquid separation is washed with ion-free water until the pH value of the washing water is less than 8; Dry at 60-100°C to obtain a spherical nickel hydroxide product coated with metal-doped α-Co(OH) ₂ .

The doping metal M of the α-Co(OH) ₂ is one or more of Y, Al, Cr, Mn, Yb, Sc, La, In, Ti or Zn.

The cobalt salt is cobalt sulfate or cobalt nitrate.

The salt of the doped metal is one or more of chloride, nitrate or soluble sulfate, and the addition ratio is M:Co=0.01～0.25 (molar ratio); the doped metal can be prepared separately , feed alone, and can also be mixed with cobalt salt solution or alkali solution to feed mixed solution.

The aqueous alkali solution is an aqueous sodium hydroxide solution or an aqueous potassium hydroxide solution.

The complexing agent is one or a mixture of two or more of ammonia, ethylenediamine, oxalic acid or citric acid. The complexing agent can be prepared as a solution and fed separately, or it can be prepared as a mixed solution with cobalt salt aqueous solution or alkali aqueous solution and fed.

The molar ratios of the complexing agent to Co are respectively: NH ₃ : Co=0.1-0.5, ethylenediamine: Co=0.1-0.3, oxalic acid: Co=0.05-0.2, citric acid: Co=0.01-0.1.

Beneficial effect of the present invention is that the α-Co(OH) of the proposed cladding doping metal element M _2The technique of spherical nickel hydroxide is compared with the technique of adding metal Co and/or its compound with traditional mechanical mixing , this α-Co(OH) ₂ coating can quickly transform into highly conductive CoOOH after oxidation or when it is first charged, thereby significantly improving the conductivity of spherical nickel hydroxide and improving the performance of Ni(OH) ₂ electrodes. Performance, and then significantly improve the performance of the battery, such as: lower charging voltage and higher discharge potential, high specific capacity and output power, longer charge/discharge cycle life and fast charging capability, overcharge/discharge resistance and It has great application value for capacity recovery after long-term storage and improvement of oxygen evolution overpotential.

Detailed ways

The invention provides a method for coating α-Co(OH) ₂ doped with metal M on the surface of spherical nickel hydroxide. The method includes the following steps in sequence:

1. Prepare a cobalt salt aqueous solution with a concentration of 0.5 to 3 mol/liter;

2. Prepare an aqueous solution of metal salt to be doped with a concentration of 0.1 to 0.5 mol/liter;

3. Prepare an aqueous alkali solution with a concentration of 3 to 8 mol/liter;

4. Prepare a certain concentration of complexing agent aqueous solution;

5. Take a certain weight of spherical nickel hydroxide and 1 to 5 times the weight of ion-free water and place them in the reactor, and pump the above-mentioned cobalt salt solution, metal element M salt solution, alkali solution and complexing agent solution respectively Continuously input into a stirred reactor, control the flow of cobalt salt aqueous solution and complexing agent aqueous solution, that is, control the molar ratio of complexing agent to Co, adjust the flow of alkaline aqueous solution so that the pH of the reaction solution in the reactor is 8~ 11. Control the reaction temperature at 30-60°C, the molar ratio of the coated metal M and Co to the coated nickel hydroxide Ni is: (Co+M): Ni=0.03-0.1, the ratio of metal M and Co The molar ratio is 0.01～0.25, and the reaction is a batch reaction;

Six. The product obtained in step 5 is transferred to the solid-liquid separator for solid-liquid separation, and the solid product obtained by the solid-liquid separation is washed with ion-free water until the pH value of the washing water is less than 8; Dry at 60-100°C to obtain a spherical nickel hydroxide product coated with metal-doped α-Co(OH) ₂ .

The doping metal M of the α-Co(OH) ₂ is one or more of Y, Al, Cr, Mn, Yb, Sc, La, In, Ti or Zn.

The cobalt salt is cobalt sulfate or cobalt nitrate.

The salt of the doped metal is one or more of chloride, nitrate or soluble sulfate, and the addition ratio is M:Co=0.01～0.25 (molar ratio); the doped metal can be prepared separately , feed alone, and can also be mixed with cobalt salt solution or alkali solution to feed mixed solution.

The aqueous alkali solution is an aqueous sodium hydroxide solution or an aqueous potassium hydroxide solution.

The complexing agent is one or a mixture of two or more of ammonia, ethylenediamine, oxalic acid or citric acid. The complexing agent can be prepared as a solution and fed separately, or it can be prepared as a mixed solution with cobalt salt aqueous solution or alkali aqueous solution and fed.

The molar ratios of the complexing agent to Co are respectively: NH ₃ : Co=0.1-0.5, ethylenediamine: Co=0.1-0.3, oxalic acid: Co=0.05-0.2, citric acid: Co=0.01-0.1.

Introduce the embodiment of the present invention below:

Example 1: Prepare 350 ml of mixed aqueous solution containing CoSO ₄ 7H ₂ O 1.8 mol/liter and YCl ₃ 0.02 mol/liter, prepare 400 mL of 0.2 mol/liter oxalic acid solution, and prepare ₄ moles of NH with a concentration of 0.9 mol/liter 400 ml of sodium hydroxide solution per liter. Weigh 600 grams of spherical nickel hydroxide, place it in a reactor with an effective volume of 5 liters, and add 0.6 liters of deionized water simultaneously. The temperature in the reactor was controlled to be 45° C., and the stirring speed was 1200 rpm. CoSO ₄ , YCl ₃ mixed aqueous solution, oxalic acid solution and sodium hydroxide aqueous solution containing NH ₃ are respectively continuously input into the reactor with a metering pump, the flow rate of CoSO ₄ , YCl ₃ mixed aqueous solution is 1.5 ml/min, the flow rate of oxalic acid solution Feed according to oxalic acid: Co (molar ratio) = 0.12, and control the pH value of the reaction solution to 10.00 ± 0.02 by adjusting the flow rate of NaOH aqueous solution. When the mixed aqueous solution of CoSO ₄ and YCl ₃ is used up, the reaction is stopped, and the feed liquid is discharged from the reactor for solid-liquid separation. The solid product was washed with deionized water at 60° C. until the pH value of the washing solution was less than 8. The washed solid product was put into a drying oven and dried at 80° C. for 4 hours to obtain a spherical nickel hydroxide product coated with yttrium-doped cobalt hydroxide.

Example 2, Co(NO ₃ ) ₂ 6H ₂ O 1.8 mol/liter, YCl ₃ 0.02 mol/liter mixed aqueous solution used for coating is 245 milliliters in total, and the flow rate of the oxalic acid solution is oxalic acid: Co (molar ratio)=0.2 Feed, the temperature in the control reactor is 60 ℃, other conditions are identical with embodiment one.

Example 3, CoSO ₄ 7H ₂ O 1.8 mol/liter, Y(NO ₃ ) ₃ 0.02 mol/liter mixed aqueous solution used for coating is 105 milliliters in total, the flow rate of the oxalic acid solution is oxalic acid: Co (molar ratio) = 0.05 feeding, the temperature in the control reactor is 30 ℃, other conditions are identical with embodiment one.

Example 4, CoSO ₄ ·7H ₂ O 1.8 mol/L, Y(SO ₄ ) ₃ 0.02 mol/L mixed aqueous solution used for coating was 245 ml in total, 400 mL of 0.2 mol/L citric acid solution was prepared, citric acid solution The flow rate is by citric acid: Co (molar ratio)=0.05 feed, other conditions are identical with embodiment one.

Example 5: Prepare 216 ml of a mixed aqueous solution containing 1.8 mol/L of CoSO ₄ ·7H ₂ O and 0.27 mol/L of YCl ₃ . Other conditions are the same as in Example 4.

Example 6: Prepare 199 ml of a mixed aqueous solution containing 1.8 mol/L of CoSO ₄ ·7H ₂ O and 0.45 mol/L of YCl ₃ , and other conditions are the same as in Example 4.

Example 7. Prepare 245 ml of a mixed aqueous solution containing 1.8 mol/L CoSO ₄ ·7H ₂ O and 0.02 mol/L ScCl ₃ . Other conditions are the same as in Example 1.

Example 8: Prepare 770 ml of a mixed aqueous solution containing CoSO ₄ 7H ₂ O 0.5 mol/liter, Sc(NO ₃ ) ₃ 0.08 mol/liter, and prepare 2 mol/liter hydrogen containing NH ₃ with a concentration of 0.1 mol/liter Sodium oxide aqueous solution 800 ml. Weigh 600 grams of spherical nickel hydroxide, place it in a reactor with an effective volume of 10 liters, and add 3 liters of deionized water simultaneously. Wherein the flow rate of oxalic acid solution is by oxalic acid: Co (mol ratio)=0.2 feed, other conditions and

Embodiment 1 is the same.

Embodiment nine, preparation contains CoSO ₄ 7H ₂ O 3 mol/liter (feed liquid temperature keeps 45 ℃), ScCl _0.45 mol/liter mixed aqueous solution 130 milliliters, the flow rate of oxalic acid solution is according to oxalic acid: Co (molar ratio)= 0.05 feed, other conditions are identical with embodiment one.

Embodiment 10, preparation contains CoSO ₄ 7H ₂ O 1.8 mol/liter, YbCl ₃ 0.18 mol/liter mixed aqueous solution 225 milliliters, preparation 0.2 mol/liter oxalic acid solution 300mL, control oxalic acid according to oxalic acid: Co (molar ratio)=0.12 Feed at a flow rate, control the pH value of the reaction solution to 8.00±0.02, and other conditions are the same as in Example 1.

Embodiment 11. The pH value of the reaction solution is controlled to be 9.00±0.02, and other conditions are the same as in Embodiment 10.

Embodiment 12. Control the pH value of the reaction solution to 10.00±0.02, and other conditions are the same as in Embodiment 10.

Embodiment 13. Control the pH value of the reaction solution to 11.00±0.02, and other conditions are the same as in Embodiment 10.

Embodiment 14, preparation contains CoSO ₄ 7H ₂ O 1.8 mol/liter, InCl _0.18 mol/liter mixed aqueous solution 225 milliliters, prepares 0.2 mol/liter citric acid solution 300mL, according to citric acid: Co (molar ratio)= 0.1 Control the feed rate of citric acid, control the pH value of the reaction solution to 9.00±0.02, control the reaction temperature to 60° C., and other conditions are the same as in Example 1.

Example 15. Prepare 300 mL of 0.2 mol/liter citric acid solution, control the flow rate of citric acid feed according to citric acid/Co (molar ratio)=0.05, control the pH value of the reaction solution to 10.00±0.02, and control the reaction temperature to 45°C , other conditions are the same as in Example 14.

Embodiment 16, prepare 300mL of 0.2 mol/liter citric acid solution, control citric acid flow feeding according to citric acid: Co (molar ratio)=0.01, control the pH value of reaction solution to be 11.00 ± 0.02, control reaction temperature to be 30 ℃ , other conditions are the same as in Example 14.

Example 17. Preparation of 225 ml of mixed aqueous solution containing CoSO ₄ 7H ₂ O 1.8 mol/liter, LaCl ₃ 0.18 mol/liter, 300 mL of 0.2 mol/liter oxalic acid solution, controlled by oxalic acid: Co (molar ratio)=0.01 Feed oxalic acid flow rate, prepare 600 milliliters of sodium hydroxide aqueous solution containing 0.2 mol/liter of ethylenediamine concentration of 3 mol/liter. The pH of the reaction solution was controlled to be 11.00±0.02, and the other conditions were the same as in Example 1.

Embodiment 18. Prepare 400 milliliters of 6 mol/liter sodium hydroxide aqueous solution containing ethylenediamine at a concentration of 0.4 mol/liter. Other conditions are the same as in Example 17.

Example 19: Prepare 400 ml of 8 mol/L sodium hydroxide aqueous solution containing ethylenediamine at a concentration of 0.54 mol/L. Other conditions are the same as in Example 17.

Example 20, Coating 245 ml of mixed aqueous solution of 1.8 mol/L CoSO ₄ and 0.02 mol/L CrCl ₃ , 400 ml of 4 mol/L sodium hydroxide aqueous solution containing NH ₃ concentration of 0.2 mol/L. Other conditions are the same as in Example 1.

Example 21: Coating used a mixed aqueous solution of 1.8 mol/L CoSO ₄ and 0.27 mol/L Cr(NO ₃ ) ₃ in total 216 ml. Other conditions are the same as in Example 20.

Example 22: Coating used a mixed aqueous solution of 1.8 mol/L CoSO ₄ and 0.45 mol/L Cr(SO ₄ ) ₃ in a total of 199 ml. Other conditions are the same as in Example 20.

Example 23: Coating used a mixed aqueous solution of 1.8 mol/L CoSO ₄ , 0.02 mol/L YCl ₃ , and 0.02 mol/L MnSO ₄ in total 245 ml. Other conditions are the same as in Example 1.

Example 24: Coating used a mixed aqueous solution of 1.8 mol/L CoSO ₄ , 0.02 mol/L Yb(NO ₃ ) ₃ , and 0.16 mol/L MnCl ₂ in total of 225 ml. Other conditions are the same as in Example 1.

Example 25: Coating used a mixed aqueous solution of 1.8 mol/L CoSO ₄ , _0.02 mol/L La(NO ₃ ) 3 , and 0.4 mol/L Mn(NO ₃ ) ₃ in total 200 ml. Other conditions are the same as in Example 1.

Example 26: Coating used a mixed aqueous solution of 1.8 mol/L CoSO ₄ , 0.02 mol/L ScCl ₃ , and 0.02 mol/L TiCl ₄ in total of 245 ml. Other conditions are the same as in Example 1.

Example 27, Coating 225 ml of a mixed aqueous solution of 1.8 mol/L CoSO ₄ , 0.02 mol/L CrCl ₃ , and 0.16 mol/L Ti(SO ₄ ) ₂ was used. Other conditions are the same as in Example 1.

Example 28: Coating uses a mixed aqueous solution of 1.8 mol/L CoSO ₄ , _0.02 mol/L In(NO ₃ ) 3 , and 0.4 mol/L Ti(NO ₃ ) ₄ in total of 200 ml. Other conditions are the same as in Example 1.

Example 29. Prepare 350 ml of mixed aqueous solution containing CoSO ₄ 7H ₂ O 1.8 mol/L, oxalic acid 0.3 mol/L, and 3.6 mol/L Hydroxide containing Al ₂ (SO ₄ ) ₃ 0.02 mol/L Sodium aqueous solution 400 ml. Other conditions are the same as in Example 1.

Example 30. Prepare 400 ml of 3.6 mol/L sodium hydroxide aqueous solution containing 0.18 mol/L NaAlO ₂ . Other conditions are the same as in Example 29.

Example 31. Prepare 400 ml of 3.6 mol/L sodium hydroxide aqueous solution containing 0.45 mol/L of Al(NO ₃ ) ₃ . Other conditions are the same as in Example 29.

Example 32. Prepare 400 ml of 3.6 mol/L sodium hydroxide aqueous solution containing 0.02 mol/L ZnSO ₄ . Other conditions are the same as in Example 29.

Example 33. Prepare 400 ml of 3.6 mol/L sodium hydroxide aqueous solution containing 0.18 mol/L Na ₂ ZnO ₂ . Other conditions are the same as in Example 29.

Example 34. Prepare 400 ml of 3.6 mol/L sodium hydroxide aqueous solution containing 0.45 mol/L of Zn(NO ₃ ) ₂ . Other conditions are the same as in Example 29.

Comparative Example 1. Prepare 350 ml of CoSO ₄ ·7H ₂ O 1.8 mol/L aqueous solution. Other conditions were the same as in Example 1, and cobalt-coated spherical nickel hydroxide without any other metal ions was prepared.

Comparative Example 2: No complexing agent was added during the coating process, and other conditions were the same as in Example 1 to prepare yttrium-doped cobalt-coated spherical nickel hydroxide.

Comparative Example 3: The coating temperature was 20° C., and the other conditions were the same as in Example 1 to prepare yttrium-doped cobalt-coated spherical nickel hydroxide.

Comparative Example 3: The coating temperature was 70° C., and other conditions were the same as in Example 1 to prepare yttrium-doped cobalt-coated spherical nickel hydroxide.

Comparative Example 4. During coating, the pH value was controlled at 7.00±0.02, and other conditions were the same as in Example 7, to prepare scandium-doped cobalt-coated spherical nickel hydroxide.

Comparative Example 5, the pH value was controlled at 12.00±0.02 during coating. Other conditions are the same as in Example 10, and ytterbium-doped cobalt-coated spherical nickel hydroxide is prepared.

Comparative Example 6: 30 ml of a mixed aqueous solution of CoSO ₄ 1.8 mol/L and InCl ₃ 0.27 mol/L was used for coating. Other conditions are the same as in Example 15, and indium-doped cobalt-coated spherical nickel hydroxide is prepared.

Comparative Example 7: 400 ml of a mixed aqueous solution of CoSO ₄ 1.8 mol/liter and CrCl ₃ 0.6 mol/liter was used for coating. Other conditions are the same as in Example 20 to prepare chromium-doped cobalt-coated spherical nickel hydroxide.

Comparative Example 8: A total of 190 ml of a mixed aqueous solution of CoSO ₄ 1.8 mol/liter and CrCl ₃ 0.54 mol/liter was used for coating. Other conditions are the same as in Example 20, and scandium-doped cobalt-coated spherical nickel hydroxide is prepared.

Battery production and performance test conditions: Weigh 15 grams each of the cobalt-coated spherical nickel hydroxide samples doped with the metal element M in Examples 1 to 34 and Comparative Examples 1 to 8, without adding other conductive agents, and adding an appropriate amount of carboxylate Methylcellulose (CMC) and polytetrafluoroethylene (PETF) emulsion were used as binders, nickel foam was used as current collector, and three positive electrodes were made for each 15 g sample, and hydrogen storage alloy electrodes were used as negative electrodes (each Containing 7.5 grams of hydrogen storage alloy), made into three AA-type nickel-hydrogen batteries. After the battery has been activated by charging and discharging at 0.2C for 3 times, the charge and discharge test at room temperature (25°C) and high temperature (60°C) is carried out (the charge and discharge rate is 1C). The test results (the average value of three batteries made for each sample) ) are listed in Table 1.

Comparative Example 9: Take 15 grams of spherical nickel hydroxide sample without cobalt coating, add 0.5 gram of nickel powder and 1.05 gram of cobaltous oxide powder as conductive agent, and other operating conditions and steps are the same as the above battery production and performance test conditions. The test results are listed in Table 1.

Table 1 sample number Tap density (g/cm ³ ) Discharge specific capacity (mAh/g) Embodiment one 2.23 271 Embodiment two 2.19 269 Embodiment Three 2.20 273 Embodiment four 2.18 265 Embodiment five 2.20 268 Embodiment six 2.26 268 Embodiment seven 2.17 269 Embodiment Eight 2.15 272 Embodiment nine 2.20 270 Embodiment ten 2.16 265 Embodiment Eleven 2.10 269 Embodiment 12 2.17 265 Embodiment Thirteen 2.21 271 Embodiment Fourteen 2.22 269 Embodiment 15 2.17 275 Embodiment sixteen 2.20 274 Embodiment 17 2.16 269 Embodiment eighteen 2.19 274 Embodiment nineteen 2.19 278 Embodiment 20 2.16 266 Embodiment 21 2.23 270 Embodiment 22 2.22 270 Embodiment 23 2.19 272

Example 24 2.18 271 Embodiment 25 2.16 268 Embodiment 26 2.22 271 Embodiment 27 2.25 272 Example 28 2.19 268 Embodiment 29 2.12 269 Example Thirty 2.17 265 Example 31 2.23 273 Example Thirty-two 2.18 271 Example thirty-three 2.20 271 Example thirty-four 2.14 269 Comparative example one 2.12 248 Comparative example two 1.79 260 Comparative example three 1.92 235 Comparative example four 1.85 246 Comparative example five 1.78 239 Comparative example six 2.20 230 Comparative example seven 1.56 219 Comparative example eight 1.89 228 Comparative example nine 2.28 239

Claims (7)

1. α-the Co in ball shape nickel hydroxide surface coating-doping metal M (OH) ₂Method, it is characterized in that: this method comprises following each step successively:

One. compound concentration is the cobalt saline solution of 0.5～3 mol;

Two. compound concentration is the aqueous solution of the doped metal salt of wanting of 0.1～0.5 mol;

Three. compound concentration is the aqueous alkali of 3～8 mol;

Four. prepare certain density complexing agent aqueous solution;

Five. take by weighing the ball-shape nickel hydroxide of constant weight and the deionized water of 1～5 times of weight and place reactor, with above-mentioned cobalt saline solution, the saline solution of metallic element M, aqueous alkali and complexing agent aqueous solution are input in the reactor of band stirring respectively continuously with pump, the flow of control cobalt saline solution and complexing agent aqueous solution, promptly control the mol ratio of complexing agent and Co, it is 8～11 that the flow of adjusting aqueous alkali makes the pH value of reactor internal reaction liquid, control reaction temperature is 30～60 ℃, the mol ratio of the Ni of the nickel hydroxide that metal M that coats and Co and quilt are coated is: (Co+M): Ni=0.03～0.1, the mol ratio of metal M and Co is 0.01～0.25, and this reaction is intermittent reaction;

Six. the step 5 products therefrom changed over to carries out Separation of Solid and Liquid in the solid-liquid separator, with the solid product of deionized water washing Separation of Solid and Liquid gained to the pH value of washings less than till 8; Product after the washing is dry under 60～100 ℃ in drier, obtains the α-Co (OH) of coating-doping metal ₂The ball-shape nickel hydroxide product.

2. according to the α-Co (OH) of the described ball shape nickel hydroxide surface coating-doping of claim 1 metal M ₂Method, it is characterized in that: described α-Co (OH) ₂Doping metals M be among Y, Al, Cr, Mn, Yb, Sc, La, In, Ti or the Zn one or more.

3. according to the α-Co (OH) of the described ball shape nickel hydroxide surface coating-doping of claim 1 metal M ₂Method, it is characterized in that: described cobalt salt is cobaltous sulfate or cobalt nitrate.

4. according to the α-Co (OH) of the described ball shape nickel hydroxide surface coating-doping of claim 1 metal M ₂Method, it is characterized in that: the salt of described doping metals is one or more in chloride, nitrate or the sulfur dissolving hydrochlorate, and the ratio of Tian Jiaing is M: Co=0.01～0.25 in molar ratio; Institute's doping metals is obtain solution separately, and charging separately also can be mixed with the mixed solution charging with cobalt saline solution or aqueous alkali.

5. according to the α-Co (OH) of the described ball shape nickel hydroxide surface coating-doping of claim 1 metal M ₂Method, it is characterized in that: described aqueous alkali is sodium hydrate aqueous solution or potassium hydroxide aqueous solution.

6. according to the α-Co (OH) of the described ball shape nickel hydroxide surface coating-doping of claim 1 metal M ₂Method, it is characterized in that: described complexing agent is one or two or more kinds the mixing in ammonia, ethylenediamine, oxalic acid or the citric acid, complexing agent is obtain solution separately, and charging separately also can be mixed with the mixed solution charging with cobalt saline solution or aqueous alkali.

7. according to the α-Co (OH) of the described ball shape nickel hydroxide surface coating-doping of claim 1 metal M ₂Method, it is characterized in that: the mol ratio of described complexing agent and Co is respectively: NH ₃: Co=0.1～0.5, ethylenediamine: Co=0.1～0.3, oxalic acid: Co=0.05～0.2, citric acid: Co=0.01～0.1.