Preparation method and application of positive and negative electrode additives for lead-carbon batteries

Abstract

The present invention discloses a preparation method and application of a positive and negative electrode additive for a lead-carbon battery, belonging to the technical field of lead-carbon batteries. The method comprises: mixing Ketjen black with an acid and uniformly dispersing the mixture; then shunting the resulting mixture at 70-90°C for 8-24 hours; cooling, washing, and centrifuging the mixture until the pH value is neutral; and then vacuum drying and grinding the mixture to obtain the positive and negative electrode additive for the lead-carbon battery. By adding a carbon material modified with an acidic oxygen-containing functional group as the positive and negative electrode additive, the present invention reduces side reactions at the positive and negative electrodes and reduces the loss of water in the electrolyte, thereby improving the cycle stability and high-rate state-of-charge cycle performance of the lead-carbon battery.

Description

Technical Field

[0001] The present invention relates to the technical field of lead-carbon batteries, and more particularly to a preparation method and application of positive and negative electrode additives for lead-carbon batteries. Background Art

[0002] With the rapid development of human economy, the demand for energy and power is increasing. Lead-acid batteries are widely used in electric vehicles, emergency power supplies, and renewable energy storage due to their mature technology, low cost, and good recyclability. However, traditional lead-acid batteries have many shortcomings during the charge and discharge cycle. (1) Short cycle life: The number of cycles of traditional lead-acid batteries is generally between 300 and 600 times. As the charge and discharge proceed, the electrode material will gradually age, reducing the performance of the battery. (2) Severe sulfation of active substances: During deep discharge and long-term static conditions, lead sulfate crystals will form and aggregate inside the lead-acid battery, making it difficult for the battery to be fully converted into positive and negative active substances during charging, resulting in reduced capacity and inability to fully recover. (3) Low energy density: The energy density of lead-acid batteries is relatively low, and the energy stored is limited under the same volume and weight.

[0003] However, lead-carbon batteries have significantly improved the above problems by adding carbon materials to the negative electrode of lead-acid batteries. The use of carbon materials not only enhances the charge and discharge performance and cycle life of the battery, but also reduces the sulfation phenomenon to a certain extent, and increases the energy density and power density of the battery, making it show great development potential in the field of new energy storage. However, lead-carbon batteries still face some challenges, such as the problem of hydrogen evolution and self-discharge at the negative electrode, and the fact that the overall rate performance and cycle performance of the battery are limited by the positive electrode. Therefore, how to reduce the hydrogen evolution phenomenon at the carbon-containing negative electrode and improve the mass transfer capacity in the thicker positive electrode active material to further improve the overall performance of the battery have become urgent problems to be solved in the current lead-acid battery field. In particular, the development of a low-cost, simple to operate and easy to industrialize additive is of great significance for the promotion and application of lead-acid batteries. Summary of the Invention

[0004] The purpose of the present invention is to overcome the above-mentioned defects of the prior art and provide a preparation method and application of positive and negative electrode additives for lead-carbon batteries. The present invention reduces the side reactions of the positive and negative electrodes and reduces the reduction of water in the electrolyte, thereby improving the cycle stability of the lead-carbon battery and the cycle performance of the high-rate state of charge.

[0005] To achieve the above object, the technical solution of the present invention is as follows:

[0006] A preparation method for positive and negative electrode additives for lead-carbon batteries comprises: mixing Ketjen black and acid and dispersing them uniformly, then shunting the obtained mixture at 70-90°C for 8-24 hours, cooling, washing, and centrifuging until the pH value is neutral, and then vacuum drying and grinding to obtain the positive and negative electrode additives for lead-carbon batteries.

[0007] Optionally, the acid is concentrated nitric acid with a concentration of 40%.

[0008] Optionally, the mass ratio of the Ketjen black to the concentrated nitric acid is 1:50-70.

[0009] Optionally, the particle size of the Ketjen black is 20-50 nm.

[0010] Optionally, the particle size of the additive is 25-50 nm.

[0011] The present invention also discloses an application of the positive and negative electrode additives for lead-carbon batteries prepared by the above-mentioned preparation method in lead-carbon batteries.

[0012] Optionally, the application includes: preparing positive electrode lead paste of a lead-carbon battery and negative electrode lead paste of a lead-carbon battery;

[0013] preparing positive and negative plates;

[0014] The positive electrode plate and the negative electrode plate are immersed in a sulfuric acid solution respectively for reaction;

[0015] After the soaking is completed, the electrode plates are cured to obtain the acid-soaked positive electrode plates and negative electrode plates;

[0016] The acid-soaked positive and negative plates are assembled into batteries. The separator is made of AGM or PE separator materials. The electrolyte is made of a material with a density of 1.4 g / cm 3 Sulfuric acid solution.

[0017] Optionally, the positive electrode lead paste of the lead-carbon battery adopts a positive and negative electrode additive for lead-carbon batteries with 0.2% by weight of lead powder added.

[0018] Optionally, the preparation method of the positive electrode plate includes: dry mixing the positive and negative electrode additives for lead-carbon batteries, lead powder, red lead, short fibers and carbon fibers in a paste mixer for 5 to 10 minutes to obtain a dry mixture; adding deionized water to the dry mixture and stirring for 10 to 20 minutes to obtain a wet mixture, and maintaining the lead paste temperature ≤ 60°C; slowly adding sulfuric acid in small amounts to the wet mixture and stirring for 10 to 20 minutes to produce a paste to obtain a positive electrode lead paste for a lead-carbon battery, which is then applied to obtain the positive electrode plate.

[0019] Optionally, the negative electrode lead paste of the lead-carbon battery is prepared by adding 0.5% by weight of lead powder as an additive for positive and negative electrodes of lead-carbon batteries.

[0020] Optionally, the preparation method of the negative plate includes: dry mixing the positive and negative electrode additives for lead-carbon batteries, lead powder, barium sulfate, short fibers, sodium lignin sulfonate and acetylene black in a paste mixer for 5 to 10 minutes to obtain a dry mixture; adding deionized water to the dry mixture and stirring for 10 to 20 minutes to obtain a wet mixture, and keeping the lead paste temperature ≤ 60°C; slowly adding sulfuric acid in small amounts to the wet mixture and stirring for 10 to 20 minutes to produce a paste to obtain a negative electrode lead paste for the lead-carbon battery, and applying it to obtain the negative electrode plate.

[0021] The implementation of the present invention will have the following beneficial effects:

[0022] The present invention significantly improves the discharge capacity and cycle life of lead-carbon batteries by adding Ketjen black, which is rich in acidic oxygen-containing functional groups, to the positive and negative lead pastes of lead-carbon batteries. Ketjen black itself has a unique hollow spherical morphology, a high specific surface area, and ultra-high conductivity, as well as a special branched chain structure. After treatment with concentrated nitric acid, the surface structure of Ketjen black does not change significantly, but the degree of graphitization defects increases, which introduces more acidic oxygen-containing functional groups to its surface, further improving its performance. Specifically, the beneficial effects of the present invention are reflected in the following aspects:

[0023] 1. Enhanced electrode stability: The addition of acidic oxygen-containing functional groups effectively inhibits side reactions in the battery electrodes, enhances the stability of the active material skeleton, improves the problem of active material shedding, and reduces water loss. These improvements significantly increase the battery's cycle life.

[0024] 2. Improving capacitance characteristics and inhibiting sulfation: Ketjen black modified with acidic oxygen-containing functional groups as a capacitive carbon material gives the battery better capacitance characteristics, improves the mass transfer efficiency of the active material, and effectively inhibits the sulfation phenomenon of the negative electrode, thereby further improving battery performance.

[0025] 3. Improved Dispersion and Contact Performance: Carbon materials modified with acidic oxygen-containing functional groups exhibit excellent dispersion in solutions and are non-sedimentary. As an additive, they promote close contact between lead powder and the carbon material, while ensuring adequate contact between the electrolyte and the active material, significantly enhancing the electrochemical performance of the battery plates and positively impacting overall battery performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a flow chart for preparing the positive lead-carbon battery of the present invention.

[0027] Figure 2 This is a flow chart for preparing the negative lead-carbon battery of the present invention.

[0028] Figure 3Graphs showing the electrochemical performance of Example 1, Example 3, and Comparative Example 1 of the present invention.

[0029] Figure 4 Graphs showing the electrochemical performance of Example 2, Example 4, and Comparative Example 2 of the present invention.

[0030] Figure 5 These are the cycling performance diagrams of different current densities of Example 1, Example 3 and Comparative Example 1 of the present invention.

[0031] Figure 6 These are the different current density cycling performance diagrams of Example 2, Example 4 and Comparative Example 2 of the present invention.

[0032] Figure 7 Graph showing the rate performance of Example 1, Example 3 and Comparative Example 1 of the present invention.

[0033] Figure 8 Graph showing the rate performance of Example 2, Example 4 and Comparative Example 2 of the present invention.

[0034] Figure 9 1 and 2 are cycle test diagrams of Example 1, Example 3 and Comparative Example 1 of the present invention.

[0035] Figure 10 Graphs showing the coulombic efficiencies of Example 1, Example 3, and Comparative Example 1 of the present invention. DETAILED DESCRIPTION

[0036] The present invention will be further described below with reference to specific examples, but the present invention is not limited thereto in any way.

[0037] Example 1

[0038] 1. Preparation of positive plate

[0039] Lead powder (100 parts), red lead (2 parts), short fibers (0.15 parts), and carbon fibers (0.2 parts) are dry-mixed in a paste mixer for 5-10 minutes to obtain a dry mix. An appropriate amount of deionized water is added and stirred for 10-20 minutes to obtain a wet mix, maintaining the lead paste temperature below 60°C. Sulfuric acid is slowly added to the wet mix in small amounts over several times, stirring evenly for 10-20 minutes to form a paste, resulting in a lead-carbon battery positive electrode paste. This paste is then applied to obtain a positive electrode plate. The resulting plate is then immersed in a sulfuric acid solution for reaction, and then cured in a constant temperature and humidity chamber using the positive electrode plate curing process.

[0040] 2. Preparation of negative plate

[0041] Lead powder (100 parts), barium sulfate (0.83 parts), short fibers (0.15 parts), sodium lignin sulfonate (0.2 parts), and acetylene black (0.2 parts) are dry-mixed in a paste mixer for 5-10 minutes to obtain a dry mix. An appropriate amount of deionized water is added and stirred for 10-20 minutes to obtain a wet mix, while maintaining the lead paste temperature below 60°C. Sulfuric acid is slowly added to the wet mix in small amounts over several times, stirring evenly for 10-20 minutes to form a paste, thereby obtaining a negative electrode lead paste for a lead-carbon battery. This paste is then applied to obtain a negative electrode plate. The resulting plate is then immersed in a sulfuric acid solution for reaction, and then cured in a constant temperature and humidity chamber using the negative electrode plate curing process.

[0042] 3. Assemble the battery

[0043] The positive plate and the negative plate are assembled into a battery in a "two-in-one" manner (two negative plates plus one positive plate), the separator is AGM, and the electrolyte is a 1.4g / cm 3 Sulfuric acid solution; after sealing, the lead-acid battery was converted into a single product according to the normal production process. This resulted in a 2V, 5Ah lead-carbon battery. This was designated as the positive electrode blank battery and numbered 1#.

[0044] Example 2

[0045] The only difference between this embodiment and embodiment 1 is that the lead-carbon battery is assembled differently, specifically as follows: in step 3, the negative plate and the positive plate are assembled into a battery using a "two-in-one" method (two positive plates plus one negative plate), which is recorded as a negative electrode blank battery and numbered 2#.

[0046] Example 3

[0047] The only difference between this embodiment and embodiment 1 is that a carbon material modified with acidic oxygen-containing functional groups is added to the positive electrode lead paste of the lead-carbon battery in this embodiment as a positive electrode additive, specifically:

[0048] Before preparing the paste, a carbon material modified with acidic oxygen-containing functional groups was prepared as follows: 0.2 parts of Ketjen Black (particle size 20-50 nm) was sonicated in 12 parts of 40% concentrated nitric acid for 30 minutes. The mixture was then split at 85°C for 12 hours. After cooling, the carbon material was repeatedly washed with ultrapure water and centrifuged until the pH was neutral. After vacuum drying and grinding, a carbon material modified with acidic oxygen-containing functional groups with a particle size of 25-50 nm was obtained for use as a cathode additive.

[0049] A carbon material modified with acidic oxygen-containing functional groups, which is 0.2% by weight of lead powder, is mixed with lead powder, red lead, short fibers, and carbon fibers. A positive electrode plate is prepared according to the treatment method of Example 1. The prepared positive electrode lead-carbon battery modified with acidic oxygen-containing functional groups is numbered 1-2#.

[0050] Example 4

[0051] The only difference between this embodiment and embodiment 2 is that a carbon material modified with acidic oxygen-containing functional groups is added to the lead paste of the lead-carbon battery negative electrode in this embodiment as a negative electrode additive, specifically:

[0052] Before preparing the paste, a carbon material modified with acidic oxygen-containing functional groups was prepared as follows: 0.5 parts of Ketjen Black (particle size 20-50 nm) was sonicated in 30 parts of 40% concentrated nitric acid for 30 minutes. The mixture was then split at 85°C for 12 hours. After cooling, the carbon material was repeatedly washed with ultrapure water and centrifuged until the pH reached neutral. After vacuum drying and grinding, a carbon material modified with acidic oxygen-containing functional groups with a particle size of 25-50 nm was obtained for use as a negative electrode additive.

[0053] A carbon material modified with acidic oxygen-containing functional groups, which is 0.5% by weight of lead powder, was mixed with lead powder, barium sulfate, short fibers, sodium lignin sulfonate, and acetylene black. A negative electrode plate was prepared according to the treatment method of Example 2. The prepared negative electrode lead-carbon battery modified with acidic oxygen-containing functional groups was numbered 2-2#.

[0054] Comparative Example 1

[0055] The only difference between this comparative example and Example 3 is that only 0.2 parts of Ketjen black without acidic functional group modification was added to the positive electrode plate of this comparative example as a positive electrode additive. The positive electrode plate was prepared according to the treatment method of Example 3, and the prepared positive electrode lead-carbon battery was numbered 1-1#.

[0056] Comparative Example 2

[0057] The only difference between this comparative example and Example 4 is that only 0.2 parts of Ketjen black without acidic functional group modification was added to the negative electrode plate of this comparative example as a negative electrode additive. The negative electrode plate was prepared according to the treatment method of Example 4, and the prepared negative electrode lead-carbon battery was numbered 2-1#.

[0058] Examples 5-8

[0059] This example differs from Example 3 in that the mass ratio of Ketjen black to concentrated nitric acid is changed. Other than these differences, the other operations are identical and will not be described in detail here. Specifically, the mass ratios of Ketjen black to concentrated nitric acid are 1:40, 1:50, 1:70, and 1:80, respectively. These are numbered 1-3#, 1-4#, 1-5#, and 1-6#, respectively.

[0060] Examples 9-12

[0061] This example differs from Example 4 in that the mass ratio of Ketjen black to concentrated nitric acid is changed. Other than these differences, the other operations are identical and will not be described in detail here. Specifically, the mass ratios of Ketjen black to concentrated nitric acid are 1:40, 1:50, 1:70, and 1:80, respectively. These are numbered 2-3#, 2-4#, 2-5#, and 2-6#, respectively.

[0062] Test Case

[0063] Electrochemical tests were performed on the plates of lead-carbon batteries with different positive electrode additives in Example 1, Example 3, and Comparative Example 1 of the present invention; and on the plates of lead-carbon batteries with different negative electrode additives in Example 2, Example 4, and Comparative Example 2 after formation to obtain the polarization current. Figure 3 、 4 As shown, it can be seen that for the lead-carbon battery with the addition of oxidized Ketjen black material, the side reactions of the electrodes are reduced to a certain extent, whether it is the positive electrode or the negative electrode, indicating that the acidic functional group-modified carbon slows down the side reactions and inhibits the sulfation of the electrode to a certain extent.

[0064] Comparison of the cycling performance of batteries with different cathode additives at different current densities of 0.1C, 0.2C, 0.5C and 0.1C and the initial discharge capacity at 0.1C. Among them, the initial discharge capacity of batteries 1#, 1-1# and 1-2# are 84.49mAh / g, 89.37mAh / g and 95.39mAh / g, respectively. Figure 5 As shown in the figure, compared with the blank battery, the battery containing the carbon material modified with acidic oxygen-containing functional groups as the positive electrode additive is about 112.9% higher than the blank battery. The initial capacities of 2#, 2-1# and 2-2# batteries are 112.85mAh / g, 123.32mAh / g and 128.49mAh / g respectively. Figure 6 As shown, the battery containing Ketjen Black Oxide exhibited approximately 113.8% higher discharge capacity than the battery with a blank negative electrode. Under different current densities, the discharge capacity of battery #1-2 was the highest. This is because the acidic oxygen-containing functional group additive of the present invention enhances the rate capability of the battery's positive electrode, improving the battery's overall ability to share high current discharges and mitigating rapid voltage drops.

[0065] Similarly, the rate performance of batteries with different negative electrode additives, 2#, 2-1# and 2-2#, is as follows: Figure 7 、 8 As shown in the figure, the simulated battery with the additive exhibited higher discharge capacity than the blank battery at both high and low rates. Because the carbon surface has numerous acidic oxygen-containing functional groups, the modified carbon provides new active reaction centers for the reduction reaction in the positive electrode. Furthermore, the oxygen-containing functional groups on the carbon surface have a strong affinity for the electrolyte solution, allowing for sufficient contact between the two, shortening charge transfer resistance, reducing internal resistance, and enhancing proton transport.

[0066] Comparison of coulombic efficiency of batteries with different electrode additives at 0.5C 100% DOD deep discharge cycle test Figure 9 、 10 As shown in Figure 2, under deep cycling, the discharge capacity of the simulated battery containing the acidic functional group-modified carbon is much higher than that of the other two groups; its coulombic efficiency remains above 96%. The extended cycle life shows that the acidic functional group-modified carbon is quite reliable as an additive for lead-carbon batteries.

[0067] The initial discharge performance of lead-carbon batteries containing different positive electrode additives, prepared using different Ketjen black to concentrated nitric acid mass ratios, and Examples 3 and 5-8 of the present invention, as well as lead-carbon batteries containing different negative electrode additives, prepared using different Ketjen black to concentrated nitric acid mass ratios, and Examples 4 and 9-12 of the present invention, were compared. The results are shown in Tables 1-2.

[0068]

[0069] The above-described embodiments merely represent several implementation methods of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. An application of a positive and negative electrode additive for a lead-carbon battery in a lead-carbon battery, characterized in that: The preparation method of the positive and negative electrode additive for lead-carbon batteries comprises: mixing Ketjen black and acid and uniformly dispersing them, then shunting the obtained mixture at 70-90° C. for 8-24 hours, cooling, washing, and centrifuging until the pH value is neutral, and then vacuum drying and grinding to obtain the positive and negative electrode additive for lead-carbon batteries; The mass ratio of the Ketjen black to the concentrated nitric acid is 1:50-70; The application includes: preparing positive lead paste of lead-carbon battery and negative lead paste of lead-carbon battery; preparing positive and negative plates; The positive electrode plate and the negative electrode plate are immersed in a sulfuric acid solution respectively for reaction; After the soaking is completed, the electrode plates are cured to obtain the acid-soaked positive electrode plates and negative electrode plates; The acid-soaked positive and negative plates are assembled into batteries. The separator is made of AGM or PE separator materials. The electrolyte is made of a material with a density of 1.4 g / cm 3 sulfuric acid solution; The negative electrode lead paste of the lead-carbon battery adopts a positive and negative electrode additive for lead-carbon batteries with 0.5% lead powder added by weight; The preparation method of the negative electrode plate comprises: dry mixing the positive and negative electrode additives for lead-carbon batteries, lead powder, barium sulfate, short fibers, sodium lignin sulfonate and acetylene black in a paste mixer for 5 to 10 minutes to obtain a dry mix; Add deionized water to the dry mix and stir for 10 to 20 minutes to obtain a wet mix, while maintaining the lead paste temperature at ≤60°C; Slowly adding sulfuric acid in small amounts to the wet mixture several times and stirring for 10 to 20 minutes to form a paste to obtain a negative electrode lead paste for a lead-carbon battery, which is then coated to obtain the negative electrode plate; The particle size of the Ketjen black is 20-50 nm; The particle size of the additive is 25-50 nm.

2. The use according to claim 1, characterized in that The acid is concentrated nitric acid with a concentration of 40%.

3. The use according to claim 1, characterized in that The positive electrode lead paste of the lead-carbon battery adopts a positive and negative electrode additive for lead-carbon batteries with 0.2% lead powder added by weight.

4. The use according to claim 1, characterized in that The preparation method of the positive electrode plate comprises: dry mixing the positive and negative electrode additives for lead-carbon batteries, lead powder, red lead, short fibers and carbon fibers in a paste mixer for 5 to 10 minutes to obtain a dry mixed material; Add deionized water to the dry mix and stir for 10 to 20 minutes to obtain a wet mix, while maintaining the lead paste temperature at ≤60°C; Sulfuric acid is slowly added to the wet mixture in small amounts and stirred for 10 to 20 minutes to form a paste, thereby obtaining a positive electrode lead paste for a lead-carbon battery, which is then applied to obtain the positive electrode plate.

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