Lead-carbon battery negative electrode material and preparation method thereof

Abstract

The application discloses a kind of lead-carbon battery negative electrode material and preparation method thereof, relate to lead-carbon battery negative electrode preparation technical field, sodium lignosulfonate, humic acid and lead powder are uniformly stirred and mixed, to obtain raw material mixture, adamantylated graphite mixed solution is added to raw material mixture, after mixing uniformly, again, dilute sulfuric acid is added to raw material mixture, uniformly stirred and mixed, to obtain negative electrode material, the application is realized by adding trace amount of adamantylated graphite, the improvement of the cycle life of lead-carbon battery.

Description

Technical Field

[0001] This invention relates to the field of lead-carbon battery anode preparation technology, and in particular to a lead-carbon battery anode material and its preparation method. Background Technology

[0002] Developing the new energy vehicle industry is one of my country's key strategic plans. Firstly, to address the energy crisis, my country must reduce its dependence on crude oil imports, which currently accounts for 48% of its economy, with 60% used for transportation. Therefore, new energy vehicles are essential. Secondly, my country is the world's second-largest emitter of CO2, with vehicle exhaust accounting for 15.9% of its total CO2 emissions. Lead-acid batteries used in electric bicycles, electric road vehicles, and tractor-trailers fall under the category of new energy and align with my country's energy conservation and emission reduction needs.

[0003] Lead-acid batteries are widely used in electric vehicles, automobiles, and energy storage due to their advantages such as cost-effectiveness, high recyclability and safety, and large market size. Their market share exceeds that of all other electrochemical batteries combined. However, lead-acid batteries still suffer from problems such as low specific energy density and short cycle life. Therefore, there is an urgent need to optimize lead-acid batteries. Currently, a common method is to introduce carbon materials into the negative electrode of lead-acid batteries. This is mainly to integrate the advantages of double-layer capacitors in terms of specific power and cycle life with lead-acid batteries, thereby improving the rate performance of lead-acid batteries and meeting their application requirements in electric vehicles.

[0004] Numerous studies have demonstrated that adding carbon materials to the negative electrode is a promising approach to mitigating sulfation and significantly improving the cycle life of lead-acid batteries. However, hydrogen evolution reaction (HER) remains a major obstacle to the application of carbon materials in lead-acid batteries. Adding excessive carbon to the negative electrode exacerbates HER, ultimately causing premature battery failure due to desiccation.

[0005] In summary, adding carbon to the negative electrode produces two results: First, the capacitive properties of carbon allow the negative electrode plate to adapt to high-rate charge pulses under certain conditions, thereby delaying sulfation. Second, it exacerbates the hydrogen evolution reaction at the negative electrode. Adding a small amount of carbon (to reach the peak cycle life of lead) primarily benefits from preventing sulfation. However, once the amount of carbon added is sufficient to overcome the drawbacks of sulfation, further increasing the carbon addition will only intensify the hydrogen evolution reaction without providing any benefit. Therefore, the amount of carbon added determines the degree to which performance is improved and the hydrogen evolution reaction is exacerbated.

[0006] Therefore, determining the optimal mixing ratio of lead powder and carbon materials to ensure the stability of the negative electrode lead-carbon composite paste, meet the strength requirements of the negative electrode plate, effectively balance hydrogen evolution suppression and performance improvement, and maximize the beneficial effects of carbon materials to effectively improve battery life is an important research direction. Summary of the Invention

[0007] To address the shortcomings of the existing technology, one objective of this invention is to provide a method for preparing a lead-carbon battery negative electrode material. This method involves adding trace amounts of advanced carbon material to the negative electrode active material in a very simple manner, thereby improving the lifespan of the lead-carbon battery. The addition method is simple and conducive to industrial production. Another objective of this invention is to provide a lead-carbon battery negative electrode material that optimizes the mixing method and addition ratio of lead powder and carbon material. Without changing the traditional formulation of the negative electrode active material, trace amounts of advanced carbon material are added to the negative electrode active material, greatly improving the performance of lead-acid batteries.

[0008] One of the objectives of this invention is achieved through the following technical solution: A method for preparing a lead-carbon battery negative electrode material includes the following steps: S1. Mix the adamantyl alkyl graphite, dispersant and deionized water evenly to obtain the adamantyl alkyl graphite mixture; S2. Sodium lignosulfonate, humic acid and lead powder are stirred and mixed evenly to obtain a raw material mixture. The adamantyl alkyl graphite mixture is added to the raw material mixture and mixed evenly. Then dilute sulfuric acid is added to the raw material mixture and stirred evenly to obtain the negative electrode material.

[0009] As a preferred embodiment, the preparation of adamantyl alkyl graphite includes the following steps: dispersing graphite in an aqueous solution of N-(1-adamantyl)ethylenediamine at a concentration of 1 mg / mL to obtain a graphite dispersion, refluxing for 24 hours, washing with deionized water and drying with nitrogen to obtain adamantyl alkyl graphite.

[0010] As a preferred option, the preparation temperature of adamantyl alkyl graphite is 25°C.

[0011] As a preferred embodiment, in step S1, the adamantyl alkyl graphite mixture consists of the following components: 0.5~2.0 wt.% adamantyl alkyl graphite, 0.35~0.42 wt.% dispersant, and the remainder being deionized water.

[0012] As a preferred option, the dispersant is polyvinylpyrrolidone.

[0013] As a preferred embodiment, in step S2, the raw material mixture consists of the following components: 0.18~0.28 wt.% sodium lignosulfonate, 0.30~0.36 wt.% humic acid, and the remainder is lead powder.

[0014] As a preferred embodiment, in step S2, the mass ratio of the raw material mixture and the adamantyl alkyl graphite mixture is 1:(0.10~0.12).

[0015] As a preferred embodiment, in step S2, the mass ratio of the raw material mixture to dilute sulfuric acid is 1:(0.45~0.50).

[0016] As a preferred option, the density of the dilute sulfuric acid is 1.40–1.43 g / cm³. 3 .

[0017] The second objective of this invention is achieved by the following technical solution: A lead-carbon battery anode material is prepared by the above-mentioned method for preparing lead-carbon battery anode materials.

[0018] The beneficial effects of this invention are: This invention, without altering the traditional formulation of the negative electrode active material, adds trace amounts of adamantyl alkyl graphite to the negative electrode active material in a very simple manner. By strictly controlling the amount of adamantyl alkyl graphite added, the cycle life of lead-carbon batteries is greatly improved. Furthermore, it solves the problem of carbon materials exacerbating hydrogen evolution at the negative electrode. This not only effectively controls costs but also effectively balances the suppression of hydrogen evolution and the improvement of performance. It is beneficial for battery manufacturers to improve the cycle life of lead-carbon batteries by adding trace amounts of adamantyl alkyl graphite to their existing negative electrode active material formulations and manufacturing processes. Attached Figure Description

[0019] Figure 1 These are structural scanning images of different negative electrode active materials on the negative electrode plates of Examples 1-3 and Comparative Examples 1-2.

[0020] Figure 2 These are the 100% DOD cycle life test results of different batteries in Examples 1-3 and Comparative Examples 1-2; Figure 3 The hydrogen evolution amount is the amount of different batteries in Examples 1-3 and Comparative Examples 1-2 float-charged for 192 hours at a voltage of 14.40V.

[0021] Figure 4 These are the 20-hour capacity test results of different batteries in Examples 1-3 and Comparative Examples 1-2. Detailed Implementation

[0022] To make the technical problem solved by the invention, the technical solution and the beneficial effects clearer, the invention will be further explained below. Example 1

[0023] A lead-carbon battery anode material includes the following preparation steps: S1. Mix 0.5 wt.% adamantyl alkyl graphite, 0.4 wt.% polyvinylpyrrolidone and the remaining deionized water evenly to obtain an adamantyl alkyl graphite mixture. S2. 0.18 wt.% sodium lignosulfonate, 0.32 wt.% humic acid, and the remaining lead powder are uniformly stirred and mixed to obtain a raw material mixture. The adamantyl alkyl graphite mixture is then added to the raw material mixture at a mass ratio of 1:0.1. After uniform mixing, a solution with a density of 1.43 g / cm³ is added. 3 Dilute sulfuric acid is added to the raw material mixture at a mass ratio of 1:0.45. The mixture is stirred while mixing to obtain the negative electrode material. Example 2

[0024] A lead-carbon battery anode material includes the following preparation steps: S1. Mix 1 wt.% adamantyl alkyl graphite, 0.35 wt.% polyvinylpyrrolidone and the remaining deionized water evenly to obtain an adamantyl alkyl graphite mixture. S2. Mix 0.2 wt.% sodium lignosulfonate, 0.3 wt.% humic acid, and the remaining lead powder evenly to obtain a raw material mixture. Add the adamantyl alkyl graphite mixture to the raw material mixture at a mass ratio of 1:0.1. Mix thoroughly, then add a solution with a density of 1.4 g / cm³. 3 Dilute sulfuric acid is added to the raw material mixture at a mass ratio of 1:0.5. The mixture is stirred while mixing to obtain the negative electrode material. Example 3

[0025] A lead-carbon battery anode material includes the following preparation steps: S1. Mix 2 wt.% adamantyl alkyl graphite, 0.4 wt.% polyvinylpyrrolidone and the remaining deionized water evenly to obtain an adamantyl alkyl graphite mixture. S2. 0.28 wt.% sodium lignosulfonate, 0.36 wt.% humic acid, and the remaining lead powder are uniformly stirred and mixed to obtain a raw material mixture. The adamantyl alkyl graphite mixture is then added to the raw material mixture at a mass ratio of 1:0.12. After uniform mixing, a solution with a density of 1.4 g / cm³ is added. 3 Dilute sulfuric acid is added to the raw material mixture at a mass ratio of 1:0.5. The mixture is stirred while mixing to obtain the negative electrode material. Comparative Example 1

[0026] S1. Mix 0.5 wt.% graphite, 0.4 wt.% polyvinylpyrrolidone and the remaining deionized water evenly to obtain a graphite mixture. S2. Mix 0.18 wt.% sodium lignosulfonate, 0.32 wt.% humic acid, and the remaining lead powder evenly to obtain a raw material mixture. Add the graphite mixture to the raw material mixture at a mass ratio of 1:0.1. Mix thoroughly, then add a solution with a density of 1.43 g / cm³. 3 Dilute sulfuric acid is added to the raw material mixture at a mass ratio of 1:0.45. The mixture is stirred while mixing to obtain the negative electrode material. Comparative Example 2

[0027] A lead-carbon battery anode material includes the following preparation steps: S1. Mix 2.5 wt.% adamantyl alkyl graphite, 0.4 wt.% polyvinylpyrrolidone and the remaining deionized water evenly to obtain an adamantyl alkyl graphite mixture. S2. 0.18 wt.% sodium lignosulfonate, 0.32 wt.% humic acid, and the remaining lead powder are uniformly stirred and mixed to obtain a raw material mixture. The adamantyl alkyl graphite mixture is then added to the raw material mixture at a mass ratio of 1:0.1. After uniform mixing, a solution with a density of 1.43 g / cm³ is added. 3 Dilute sulfuric acid is added to the raw material mixture at a mass ratio of 1:0.45. The mixture is stirred while mixing to obtain the negative electrode material.

[0028] In Examples 1-3 and Comparative Example 2, the preparation steps of the adamantyl alkyl graphite mixture are as follows: at 25°C, graphite is dispersed in an aqueous solution of N-(1-adamantyl)ethylenediamine at a concentration of 1 mg / mL, the graphite dispersion is refluxed for 24 hours, then washed with deionized water and dried with nitrogen to obtain adamantyl alkyl graphite.

[0029] Battery assembly of the negative electrode materials of Examples 1-3 and Comparative Examples 1-2 includes the following steps: preparing negative electrode plates by sequentially performing coating, curing, drying and formation processes according to conventional processes, and assembling 12V22Ah cycle lead-carbon batteries using current methods.

[0030] Scanning electron microscopy (SEM) was performed on the different negative electrode active materials on the negative electrode plates of Examples 1-3 and Comparative Examples 1-2. The morphological and structural results are as follows: Figure 1As shown in the figure, compared to adding graphite, the Pb sheets inside the negative electrode plate with adamantyl alkylated graphite are smaller. These Pb sheets are loosely stacked together, which not only increases the porosity of the material but also facilitates the diffusion of electrolyte in the space between the Pb sheets, thereby increasing the contact area between Pb and sulfuric acid electrolyte. The negative electrode plate in Example 2 achieves optimal porosity and specific surface area. Compared to Comparative Example 1, the negative electrode plates in Examples 1-3 all show improved porosity and specific surface area, which is more conducive to the diffusion of sulfuric acid electrolyte in the space of the negative electrode active material, increasing the contact area between the negative electrode active Pb and sulfuric acid electrolyte. This promotes the reduction reaction under high charge-discharge rates, inhibits the growth of lead sulfate crystals, alleviates negative electrode sulfation, and improves the cycle life of the lead-carbon battery.

[0031] The lead-carbon batteries of Examples 1-3 and Comparative Examples 1-2 were subjected to a 100% DOD cycle life test. The test method is as follows: 1) After the lead-carbon batteries were fully charged, they were discharged at a constant current of 0.45C to 10.5V; 2) After the discharge was completed, the batteries were charged at a constant voltage of 14.8V with a current-limited limit of 0.45C for 3.5 hours, and then left to stand for 0.5 hours; 3) Steps 1) and 2) were repeated until the discharge time was less than 1.6 hours, at which point the test was terminated. The discharge time of each cycle was recorded, and the discharge capacity was calculated. The test results are as follows: Figure 2 As shown.

[0032] The hydrogen evolution rate of the lead-carbon batteries in Examples 1-3 and Comparative Examples 1-2 was tested, and the test results are as follows: Figure 3 As shown. The specific test method is as follows: 1) After the lead-carbon battery is fully charged, it is float-charged at a constant voltage of 14.40V for 72 hours in an environment of 20℃~25℃; 2) After float charging for 72 hours, gas collection begins and continues for 192 hours, and the total amount of gas collected, V (mL), is measured and recorded; 3) The amount of hydrogen evolution of the lead-carbon battery under the float charging voltage is calculated, and the results are shown in the figure. Figure 3 As shown, the calculation method is as follows:

[0033] In the formula: G – The amount of gas released, in milliliters (mL). V – Volume of gas released, expressed in milliliters per ampere-hour [mL / (Ah·h)]; G e -- Actual battery capacity, in ampere-hours (Ah). t -- the time taken to collect the gas, in hours (h).

[0034] Combination Figure 2 and Figure 3It is known that when the amount of adamantyl alkyl graphite mixture added is in the range of 0.5~2.0 wt.%, the performance of the assembled lead-carbon battery is improved, especially the lead-carbon battery of Example 2 reaches the peak of cycle life.

[0035] Compared with Comparative Example 1, it was found that the hydrogen evolution reaction was weakened by adding adamantyl alkyl graphite. Compared with Comparative Example 2, it was found that when the amount of adamantyl alkyl graphite mixture added was in the range of 0.5-1 wt.%, the increase in hydrogen evolution was slow, but the cycle life was significantly improved. When the amount of adamantyl alkyl graphite mixture added was in the range of 1-2 wt.%, the increase in hydrogen evolution was faster, but it was still within a reasonable range to balance cycle life performance. However, when the amount of adamantyl alkyl graphite mixture added was greater than 2 wt.%, the amount of hydrogen evolution increased almost linearly. At this time, the battery water loss caused by the hydrogen evolution reaction took precedence, and the performance dropped rapidly. Therefore, in order to balance the performance of the battery, the amount of adamantyl alkyl graphite mixture added should be strictly controlled within a reasonable range.

[0036] The lead-carbon batteries of Examples 1-3 and Comparative Examples 1-2 were subjected to a 20-hour capacity test. The test method is as follows: the batteries were discharged at a constant current of 0.05 times the capacity (0.05C=1.1A) to a cutoff voltage of 10.5V, and the charge-discharge curves were recorded to evaluate the battery capacity. The 20-hour capacity test results are as follows: Figure 4 As shown in the figure, the discharge capacity of the battery increases with the increase of the amount of adamantyl alkyl graphite mixture added, especially the lead-carbon battery of Example 2, which reaches the peak capacity.

[0037] This invention, without altering the traditional formulation of the negative electrode active material, adds trace amounts of adamantyl alkyl graphite to the negative electrode active material in a very simple manner. By strictly controlling the amount of adamantyl alkyl graphite added, the cycle life of lead-carbon batteries is greatly improved. It also solves the problem of carbon materials aggravating hydrogen evolution at the negative electrode, effectively controlling costs. This invention is beneficial for battery manufacturers to improve the cycle life of lead-carbon batteries by adding trace amounts of adamantyl alkyl graphite to their existing negative electrode active material formulations and manufacturing processes.

[0038] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention shall fall within the protection scope of the present invention.

Claims

1. A method for preparing a lead-carbon battery negative electrode material, characterized in that, Includes the following steps: S1. Mix the adamantyl alkyl graphite, dispersant and deionized water evenly to obtain the adamantyl alkyl graphite mixture; The adamantyl alkylated graphite mixture consists of the following components: 0.5~2.0 wt.% adamantyl alkylated graphite, 0.35~0.42 wt.% dispersant, and the remainder is deionized water; S2. Sodium lignosulfonate, humic acid and lead powder are stirred and mixed evenly to obtain a raw material mixture. The adamantyl alkyl graphite mixture is added to the raw material mixture and mixed evenly. Then, dilute sulfuric acid is added to the raw material mixture and stirred evenly to obtain the negative electrode material. The mass ratio of the raw material mixture to the adamantyl alkyl graphite mixture is 1: (0.10~0.12).

2. The method for preparing a lead-carbon battery negative electrode material according to claim 1, characterized in that, Preparation of adamantyl alkyl graphite The process includes the following steps: dispersing graphite in an aqueous solution of N-(1-adamantyl)ethylenediamine at a concentration of 1 mg / mL to obtain a graphite dispersion, refluxing for 24 hours, washing with deionized water, and drying with nitrogen to obtain adamantyl graphite.

3. The method for preparing a lead-carbon battery negative electrode material according to claim 2, characterized in that, The preparation temperature of adamantyl alkyl graphite is 25℃.

4. The method for preparing a lead-carbon battery negative electrode material according to claim 1, characterized in that, The dispersant is polyvinylpyrrolidone.

5. The method for preparing a lead-carbon battery negative electrode material according to claim 1, characterized in that, In step S2, the raw material mixture consists of the following components: 0.18~0.28 wt.% sodium lignosulfonate, 0.30~0.36 wt.% humic acid, and the remainder is lead powder.

6. The method for preparing a lead-carbon battery negative electrode material according to claim 1, characterized in that, In step S2, the mass ratio of the raw material mixture to dilute sulfuric acid is 1:(0.45~0.50).

7. The method for preparing a lead-carbon battery negative electrode material according to claim 1, characterized in that, The density of dilute sulfuric acid is 1.40–1.43 g / cm³. 3 .

8. A lead-carbon battery negative electrode material, characterized in that, It is prepared by the method for preparing lead-carbon battery anode material according to any one of claims 1 to 7.

Images