CN105958077A - Method for preparing tetrabasic lead sulfate with small grain size with sol-gel method - Google Patents

Abstract

A method for preparing small-grain size tetrabasic lead sulfate by a sol-gel method. Under the condition of stirring in a water bath, lead acetate and complexing agent are dissolved in distilled water, and then sulfuric acid solution and dispersant are added to obtain lead oxide/sulfuric acid Lead sol; continue to stir the lead oxide/lead sulfate sol in a water bath, evaporate to dryness, and respectively undergo low-temperature pre-sintering and high-temperature sintering in an air atmosphere to obtain tetrabasic lead sulfate powder, grind and sieve to obtain small crystals Particle size tetrabasic lead sulfate. The advantages are: the preparation process, conditions and equipment are relatively simple, the synthesized tetrabasic lead sulfate has a small grain size, and has excellent performance as an additive to positive active materials, and can increase its specific capacity while increasing the cycle life of positive active materials.

Description

A kind of method that sol-gel method prepares the tetrabasic lead sulfate of small grain size

technical field

The invention relates to a method for preparing tetrabasic lead sulfate (4BS) with small grain size by a sol-gel method.

Background technique

Tetrabasic lead sulfate (4BS) is one of the components of the positive electrode active material during the curing process, and can be converted into α-PbO ₂ with a relatively coarse grain size during the chemical formation process. α-PbO ₂ can be used as the active material skeleton to ensure the smooth progress of charge and discharge, and improve the cycle life of the positive electrode active material of the lead-acid battery. In order to increase the proportion of 4BS in the positive electrode active material, it is common practice to add a part of 4BS as a seed crystal during the process of mixing with lead paste to promote the formation of 4BS during the curing process. The current commercial tetrabasic lead sulfate (4BS) has a large grain size and interlocking connections, so that a part of 4BS cannot be converted into α-PbO ₂ during the chemical formation process, and the specific capacity will decrease as an additive.

Contents of the invention

The technical problem to be solved in the present invention is to provide a method for preparing small grain size tetrabasic lead sulfate by sol-gel method, the preparation process, conditions and equipment of this method are relatively simple, and the synthetic tetrabasic lead sulfate grain size is small , has excellent performance as a positive electrode active material additive.

A kind of sol-gel method prepares the method for tetrabasic lead sulfate of small grain size, and its concrete steps are as follows:

1.1. Under the condition of stirring in a water bath, dissolve lead acetate and complexing agent in distilled water, then add sulfuric acid solution and dispersant to obtain lead oxide/lead sulfate sol;

1.2. Continue stirring the lead oxide/lead sulfate sol obtained in step 1.1 in a water bath at the same temperature as step 1.1, and evaporate to dryness to obtain lead oxide/lead sulfate xerogel;

1.3. The lead oxide/lead sulfate xerogel obtained in step 1.2 is subjected to low-temperature pre-sintering and high-temperature sintering respectively in an air atmosphere to obtain tetrabasic lead sulfate powder;

1.4. After grinding the powder obtained in step 1.3, pass through a 200-mesh sieve to obtain tetrabasic lead sulfate (4BS) with a small grain size.

Further, the grain size of the tetrabasic lead sulfate with small grain size is 500nm-1μm.

Further, the molar ratio of the lead acetate to the complexing agent is 1:1˜1:3.

Further, the complexing agent is citric acid or EDTA.

Further, the temperature of the water bath heating is 80°C to 90°C.

Further, the mass concentration of the sulfuric acid solution is 15%-60%, and the sulfuric acid solution accounts for 3%-9% of the total mass of lead acetate.

Further, the dispersant is ethylene glycol, fumed silica or aluminum oxide.

Further, the mass ratio of the lead acetate to the dispersant is 100:2˜100:6.

Further, the low-temperature pre-sintering temperature is 150°C-250°C, and the sintering time is 1.5h-3.5h.

Further, the high-temperature sintering temperature is 300°C-700°C, and the sintering time is 5h-7h.

Beneficial effects of the present invention:

(1) The preparation process, conditions and equipment are relatively simple. Using ethylene glycol, fumed silica or aluminum oxide as a dispersant can prevent the agglomeration between nano-4BS particles in the synthesis process, and can increase the concentration of tetrabasic lead sulfate. High activity and chemical conversion rate; the synthetic product has high purity, small tetrabasic lead sulfate grain size, uniform dispersion, and can be controlled at 500nm-1μm, and has excellent performance as a positive active material additive.

(2) Adding 1% of the synthesized tetrabasic lead sulfate to the positive electrode active material to prepare a plate and assemble it into an experimental lead-acid battery. Through the constant current charge and discharge test, it can be seen that the specific capacity of the positive active material can reach 94.89mAh.g ^-1 and 86.42mAh when charged at a current of 0.25C to a constant voltage of 2.42V and discharged at a current of 0.1C, 0.25C and 0.5C respectively. .g ^-1 and 70.78mAh.g ^-1 . Under 0.5C charge and discharge, after 100 charge and discharge cycles, the specific capacity has no obvious decay. It shows that adding the small grain size and high-purity tetrabasic lead sulfate (4BS) prepared by the present invention can improve the specific capacity while increasing the cycle life of the positive electrode active material.

Description of drawings

Fig. 1 is the XRD pattern of tetrabasic lead sulfate of the present invention;

Fig. 2 is the SEM figure of tetrabasic lead sulfate of the present invention;

Fig. 3 utilizes the tetrabasic lead sulfate that the present invention (corresponding embodiment 1) obtains, adds in the positive electrode lead paste by 1% of lead powder quality, the SEM figure of lead paste after solidification;

Fig. 4 is to utilize the tetrabasic lead sulfate that the present invention (corresponding embodiment 1) obtains, add in the positive lead paste by 1% of lead powder quality, the positive plate that obtains after curing is assembled into 2V experimental type lead-acid battery, Charge and discharge with a current of 0.25C to a constant voltage of 2.42V, and discharge with a current of 0.1C, 0.25C and 0.5C, respectively, to obtain the charge-discharge curve;

Fig. 5 is to utilize the tetrabasic lead sulfate that the present invention (corresponding embodiment 1) obtains, add in the positive pole lead paste by 1% of lead powder quality, the positive pole plate that obtains through curing is assembled into 2V experimental type lead-acid battery, with 0.5C current charging to 2.42V constant voltage, 0.5C current discharge to 1.75V for cycle charge and discharge test, obtained cycle performance curve.

detailed description

Example

1.1. Under the condition of stirring in a water bath at 80°C to 90°C, dissolve lead acetate and complexing agent with a molar ratio of 1:1 to 1:3 in distilled water. The complexing agent is citric acid or EDTA, and then add sulfuric acid Solution and dispersant, the mass concentration of the sulfuric acid solution is 15% to 60%, the sulfuric acid solution accounts for 3% to 9% of the total mass of lead acetate, and the dispersant is ethylene glycol, fumed silica or tris Al2O3, the mass ratio of the lead acetate to the dispersant is 100:2 to 100:6 to obtain lead oxide/lead sulfate sol;

1.2. Continue to evaporate the lead oxide/lead sulfate sol obtained in step 1.1 under the condition of stirring in a water bath at 80° C. to 90° C. to obtain lead oxide/lead sulfate xerogel;

1.3. The lead oxide/lead sulfate xerogel obtained in step 1.2 is pre-sintered at a low temperature of 150°C to 250°C for 1.5h to 3.5h and sintered at a high temperature of 300°C to 700°C for 5h to 7h in an air atmosphere to obtain the four bases Formula lead sulfate powder;

1.4. After grinding the powder obtained in step 1.3, pass through a 200-mesh sieve to obtain tetrabasic lead sulfate (4BS). The grain size of the tetrabasic lead sulfate is 500 nm-1 μm.

Example 1

1.1. Weigh 6.5g of lead acetate and 7.68g of citric acid complexing agent (molar ratio 1:2), dissolve them in 100mL of distilled water under the condition of stirring in a water bath at 90°C, add 0.58g of sulfuric acid solution with a mass concentration of 51%, After the fumed silica dispersant of 0.28g, lead oxide/lead sulfate sol is obtained;

1.2. Continue to stir the lead oxide/lead sulfate sol obtained in step 1.1 in a water bath at 90°C, and evaporate to dryness to obtain lead oxide/lead sulfate xerogel;

1.3. The lead oxide/lead sulfate xerogel obtained in step 1.2 was pre-sintered at 150°C for 3.5 hours at a low temperature and sintered at a high temperature at 500°C for 5 hours in an air atmosphere to obtain tetrabasic lead sulfate powder;

1.4. After grinding the powder obtained in step 1.3, pass through a 200-mesh sieve to obtain tetrabasic lead sulfate (4BS). The grain size of the tetrabasic lead sulfate is 500 nm-1 μm.

The tetrabasic lead sulfate (4BS) obtained in Example 1 was tested by XRD, and the XRD diffraction peak spectrum of the material was obtained, as shown in FIG. 1 . As can be seen from Figure 1, the diffraction peaks of the obtained tetrabasic lead sulfate are in good agreement with the standard card, and the purity of the material is relatively high. Although a fumed silica dispersant was added in the process of synthesizing small grain size lead sulfate (4BS), since fumed silica is an amorphous structure, no diffraction peaks appear in the XRD test, and in the process of calculating the purity The amount of fumed silica was not taken into account.

The tetrabasic lead sulfate (4BS) obtained in Example 1 is subjected to a scanning electron microscope (SEM) test, and the obtained microscopic topography is shown in FIG. 2 . It can be seen from Fig. 2 that the grain distribution of the obtained small grain size tetrabasic lead sulfate (4BS) is uniform and the grain size can be controlled between 500nm and 1 μm. This illustrates that the method of the present invention can be used to synthesize small grain size tetrabasic lead sulfate (4BS).

The tetrabasic lead sulfate (4BS) that embodiment 1 obtains is added in positive electrode lead paste by 1% of lead powder quality, obtains positive plate after curing, it carries out scanning electron microscope test to it, the microcosmic topography figure that obtains, As shown in Figure 3. It can be seen from Figure 3 that a large number of rod-shaped 4BS appeared in the cured positive active material, and the particles interweaved to form a network structure, which could provide a structural framework for the positive active material.

The tetrabasic lead sulfate (4BS) that embodiment 1 obtains is added in the positive pole lead paste by 1% of the lead powder quality, and the positive plate obtained after curing is assembled into a 2V experimental type lead-acid battery with it. After formation, a constant current charge and discharge test was carried out to obtain charge and discharge curves at different discharge rates, as shown in Figure 4. Through the constant current charge and discharge test, it can be seen that the specific capacity of the positive active material can reach 94.89mAh.g ^-1 and 86.42mAh when charged at a current of 0.25C to a constant voltage of 2.42V and discharged at a current of 0.1C, 0.25C and 0.5C respectively. .g ^-1 and 70.78mAh.g ^-1 .

The tetrabasic lead sulfate (4BS) that embodiment 1 obtains is added in the positive pole lead paste by 1% of the lead powder quality, and the positive plate obtained after curing is assembled into a 2V experimental type lead-acid battery with it. After the formation, the cycle charge and discharge test is carried out, and the cycle performance curve obtained is shown in Figure 5. The test results show that under the condition of 0.5C charge and discharge, after 100 charge and discharge cycles, the capacity does not decrease significantly. It shows that adding the tetrabasic lead sulfate (4BS) synthesized by the present invention into the lead-acid positive active material can increase the specific capacity while improving the cycle life of the positive active material.

Example 2

1.1. Weigh 6.5g of lead acetate and 17.53g of EDTA complexing agent (molar ratio 1:3), dissolve them in 100mL of distilled water under the condition of stirring in a water bath at 80°C, add 0.20g of sulfuric acid solution with a mass concentration of 60%, 0.13 After the fumed silica dispersant of g, continue to stir, obtain plumbous oxide/lead sulfate sol;

1.2. Continue to evaporate the lead oxide/lead sulfate sol obtained in step 1.1 under the condition of stirring in an 80°C water bath to obtain lead oxide/lead sulfate xerogel;

1.3. The lead oxide/lead sulfate xerogel obtained in step 1.2 was pre-sintered at 200°C for 2 hours at a low temperature and sintered at a high temperature at 400°C for 6 hours in an air atmosphere to obtain tetrabasic lead sulfate powder;

1.4. After grinding the powder obtained in step 1.3, pass through a 200-mesh sieve to obtain tetrabasic lead sulfate (4BS).

Example 3

1.1. Weigh 6.5g of lead acetate and 3.84g of citric acid complexing agent (molar ratio 1:1), dissolve them in 100mL of distilled water under the condition of stirring in a water bath at 85°C, add 0.58g of sulfuric acid solution with a mass concentration of 15%, After the aluminum oxide dispersant of 0.39g, obtain plumbous oxide/lead sulfate sol;

1.2. Continue to stir the lead oxide/lead sulfate sol obtained in step 1.1 in a water bath at 85°C, and evaporate to dryness to obtain lead oxide/lead sulfate xerogel;

1.3. The lead oxide/lead sulfate xerogel obtained in step 1.2 was pre-sintered at 550°C for 1.5 hours at a low temperature and sintered at a high temperature at 300°C for 7 hours in an air atmosphere to obtain tetrabasic lead sulfate powder;

1.4. After grinding the powder obtained in step 1.3, pass through a 200-mesh sieve to obtain tetrabasic lead sulfate (4BS).

Example 4

1.1. Weigh 6.5g of lead acetate and 7.68g of citric acid complexing agent, dissolve them in 100mL of distilled water under the condition of stirring in a water bath at 90°C, add 0.58g of sulfuric acid solution with a mass concentration of 30%, and disperse with 0.30g of ethylene glycol After the preparation, lead oxide/lead sulfate sol is obtained;

1.2. Continue to stir the lead oxide/lead sulfate sol obtained in step 1.1 in a water bath at 90°C, and evaporate to dryness to obtain lead oxide/lead sulfate xerogel;

1.3. The lead oxide/lead sulfate xerogel obtained in step 1.2 was pre-sintered at 550°C for 1.5 hours at a low temperature and sintered at a high temperature at 700°C for 5 hours in an air atmosphere to obtain tetrabasic lead sulfate powder;

1.4. After grinding the powder obtained in step 1.3, pass through a 200-mesh sieve to obtain tetrabasic lead sulfate (4BS).

The tetrabasic lead sulfate (4BS) of the embodiment 2～4 of table 1 of the present invention, add the electrode prepared in the positive electrode lead paste by 1% of lead powder quality and assemble into the electrochemical performance table of 2V experimental type lead-acid battery

The above are only specific embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (10)

1. the method that sol-gal process prepares little crystallite dimension four basic lead sulphate, is characterized in that:

Specifically comprise the following steps that

1.1, under the conditions of stirring in water bath, take lead acetate and chelating agent is dissolved in distilled water, be subsequently adding sulfuric acid solution and divide Powder, obtains lead oxide/lead sulfate colloidal sol；

1.2, lead oxide step 1.1 obtained/lead sulfate colloidal sol continues to carry out water-bath at temperature identical with step 1.1 and stirs Mix, be evaporated, obtain lead oxide/lead sulfate xerogel；

1.3, lead oxide step 1.2 obtained/lead sulfate xerogel is in air atmosphere, respectively through low temperature presintering knot and height Temperature sintering, obtains four basic lead sulphate powder；

1.4, powder step 1.3 obtained is polished, crosses 200 mesh sieves, obtains four basic lead sulphates of little crystallite dimension (4BS)。

Sol-gal process the most according to claim 1 prepares the method for little crystallite dimension four basic lead sulphate, it is characterized in that: The crystallite size of four basic lead sulphates of described little crystallite dimension is 500nm-1 μm.

Sol-gal process the most according to claim 1 prepares the method for little crystallite dimension four basic lead sulphate, it is characterized in that: Described lead acetate is 1:1～1:3 with the mol ratio of chelating agent.

4. the method preparing little crystallite dimension four basic lead sulphate according to the sol-gal process described in claim 1 or 3, its feature It is: described chelating agent is citric acid or EDTA.

Sol-gal process the most according to claim 1 prepares the method for little crystallite dimension four basic lead sulphate, it is characterized in that: The temperature of heating in water bath is 80 DEG C～90 DEG C.

Sol-gal process the most according to claim 1 prepares the method for little crystallite dimension four basic lead sulphate, it is characterized in that: The mass concentration of described sulfuric acid solution is 15%～60%, and described sulfuric acid solution accounts for the 3%～9% of lead acetate gross mass.

Sol-gal process the most according to claim 1 prepares the method for little crystallite dimension four basic lead sulphate, it is characterized in that: Described dispersant is ethylene glycol, aerosil or aluminium sesquioxide.

Sol-gal process the most according to claim 1 prepares the method for little crystallite dimension four basic lead sulphate, it is characterized in that: Described lead acetate is 100:2～100:6 with the mass ratio of dispersant.

Sol-gal process the most according to claim 1 prepares the method for little crystallite dimension four basic lead sulphate, it is characterized in that: Low temperature presintering junction temperature is 150 DEG C～250 DEG C, and sintering time is 1.5h～3.5h.

Sol-gal process the most according to claim 1 prepares the method for little crystallite dimension four basic lead sulphate, its feature It is: high temperature sintering temperature is 300 DEG C～700 DEG C, and sintering time is 5h～7h.