A controllable preparation method of carbon-based negative electrode additive for lead-carbon batteries

Abstract

The application discloses a controllable preparation method of a carbon-based negative electrode additive of a lead-carbon battery, and is a preparation method for realizing accurate regulation of lead and carbon through an efficient and stable complex precipitation coupling carbon thermal reduction strategy. Compared with other methods, lead particles of the carbon-based negative electrode additive of the lead-carbon battery prepared through the method are uniformly anchored on the surface of carbon material, the lead loading capacity is controllable, lead and carbon are tightly combined, no impurities are introduced, and the carbon material can retain high specific surface area and porosity, and is excellent in repeatability and stability. The preparation process of the method comprises the following steps: dispersing complex precipitates formed by an organic acid and a soluble lead salt in an aqueous solution onto carbon-based material, washing and drying the filtrate, and pyrolyzing the filtrate in a protective gas to obtain a negative electrode additive of a lead-carbon battery. The additive avoids the floating carbon phenomenon in the mixing process with paste, improves the uniformity of the carbon material in the negative plate, inhibits the hydrogen evolution reaction of the negative plate, and improves the high-rate cycle life. The application is simple, controllable and low in cost, and is easy to realize large-scale preparation.

Description

TECHNICAL FIELD

[0001] The application relates to a controllable preparation method of a carbon-based negative electrode additive of a lead-carbon battery and belongs to the technical field of lead-carbon batteries. TECHNICAL BACKGROUND

[0002] In recent years, as an advanced lead-acid battery, the lead-carbon battery not only has the advantages of safety, low cost and high recovery rate of a lead-acid battery, but also has various forms of carbon added to the negative electrode, so that the microstructure of the negative active material is optimized, the porosity of the negative active material is increased, and the electrode reaction kinetics is improved, thereby relieving the sulfation of the negative electrode and improving the competitiveness of the lead-carbon battery in the fields of hybrid electric vehicles, renewable energy storage and telecom backup power supply.

[0003] However, the addition of carbon to the negative active material also brings some challenges. Carbon-based materials with a lower hydrogen evolution overpotential intensify the hydrogen evolution reaction, thereby reducing the capacitance contribution of the carbon-based material and the coulombic efficiency of the battery, leading to the dehydration of the electrolyte. With the circulation, the electrode structure is also damaged and failure mechanisms such as negative electrode swelling are triggered. In addition, due to the differences in physical and chemical properties between lead and carbon, the carbon material is often unevenly distributed in the negative electrode and the lead-carbon bonding force is weak, and even carbon floating phenomenon occurs. In the long run, the cycle life of the lead-carbon battery has not been well demonstrated. In order to achieve the purposes of inhibiting the hydrogen evolution of the negative electrode of the lead-carbon battery and relieving the sulfation, an effective solution is to prepare a lead-carbon composite material as a negative electrode additive of the lead-carbon battery.

[0004] Up to now, the main preparation methods of lead-carbon composite materials include electrodeposition, solid-phase ball milling, liquid-phase impregnation deposition and precipitation, organic complexation and pyrolysis, etc. Chinese patent CN 102074702 A uses electrodeposition method to deposit lead particles on activated carbon, but lead particles can only be deposited on the surface of carbon coating, and the process of scraping from the mother plate and crushing will also damage the structure of the composite material. Moreover, electrodeposition uses a higher-priced but non-conductive binder (such as polyvinylidene fluoride), which reduces the performance of the composite material and increases the preparation cost. CN 102945951 A ball-mills activated carbon and organic carbon source together, the mixture is granulated by spray drying, and then pyrolysis and carbonization, the activated carbon agglomerates after pyrolysis treatment are exposed to lead vapor for plating lead, and the lead content is controlled by controlling the time. This method is complex, and there is a risk of lead pollution and lead poisoning. CN 103035895 A mixes organic carbon source and lead powder in proportion and then ball-mills, and then carbonizes in a tube furnace, and then washes with organic solvent and deionized water to obtain carbon-coated lead powder composite material. CN 108899492 A mixes solid lead salt, solid strong base and carbon material by ball-milling, and the raw materials react chemically under the action of mechanical force to generate lead-carbon composite material. The material prepared by the above-mentioned solid-phase ball-milling method has low purity and uneven particle size distribution, and the friction loss between the grinding body and the machine body is large and will pollute the product. CN 109860531 A uses oxidized carbon to impregnate and adsorb lead ions dispersed with a surfactant, and then obtains nano lead-carbon composite material by carbon thermal reduction. The lead particles of the prepared composite material are unevenly distributed and the lead loading is uncontrollable, and the repeatability is poor. CN 110137452 A and CN 103035894 A use deposition and precipitation method to deposit lead hydroxide or lead carbonate on carbon material and pyrolysis to form lead-carbon composite material. Although the lead content can be controlled, there are problems such as the need for precise pH control, poor reproducibility and uniformity, and poor combination of lead and carbon carrier affecting the overall performance of the material. CN 104505511 A uses lead organic complex as precursor, and calcines and pyrolyzes at 200-1000℃ in an oxidizing atmosphere or inert protective atmosphere, the carbon-containing precursor generates amorphous carbon skeleton, and the lead salt decomposes or reduces to lead / lead oxide nanoparticles and firmly embeds into the carbon matrix to form a stable and efficient lead-carbon composite structure. However, the specific surface area and capacitance of the lead-carbon composite material synthesized by this method are too small, and the charging acceptance ability of the lead-carbon battery and the improvement of the electrochemical active area of the negative active material are limited. CN 105990578 A uses lead ions complexed with alginate as precursor to prepare active material for lead-carbon battery electrode by low-temperature carbonization. Due to the large molecular structure of lead alginate, the decomposition difficulty increases, a large amount of amorphous carbon and lead oxide is generated during carbonization, which shows low conductivity, thereby affecting the electrochemical performance of the final product.It can be seen that the current preparation method is not economically feasible for large-scale production, or the process is complex, the flow is long, impurities are easily mixed, the performance is unstable, and the scale production is seriously affected. In this sense, it is urgent to develop a more concise, accurate and controllable preparation process to break through this technical difficulty. SUMMARY

[0005] The technical problem to be solved by the present application is to overcome the shortcomings in the prior art, and to provide a controllable preparation method of carbon-based negative electrode additive of lead-carbon battery, which realizes accurate control of lead and carbon through efficient and stable complex precipitation coupling carbon thermal reduction strategy.

[0006] To solve the technical problem, the technical scheme adopted by the present application is:

[0007] A controllable preparation method of carbon-based negative electrode additive of lead-carbon battery is provided, which comprises the following steps:

[0008] 1) Mix soluble lead salt, sodium acetate and carbon-based material in pure water to obtain a mixed solution A; the concentration of soluble lead salt in the mixed solution A is 0.01mol / L -1 ~0.10mol / L -1 , the concentration of sodium acetate is 0.05mol / L -1 ~0.10mol / L -1 , and the concentration of carbon-based material is 0.2g / mL -1 ~1.0g / mL -1 , and sodium acetate is added to maintain pH stability and provide buffering function;

[0009] The carbon-based material includes one or more of activated carbon, carbon black, expanded graphite, graphene, carbon nanotube and carbon fiber, and the specific surface area is 20m 2 g -1 ~2000m 2 g -1 , and the particle size D90 is 20nm~150μm;

[0010] 2) Prepare an organic acid solution B with a concentration of 0.01mol / L -1 ~0.10mol / L -1 ; the organic acid is one or a combination of more than one organic acid that can form a complex with lead ions to generate a precipitate;

[0011] 3) Under constant stirring, add solution B to mixed solution A at a speed of 0.5mL / min -1 ~5.0mL / min -1 , so that the white precipitate deposited on the carbon-based material is deposited on the carbon-based material, and after standing, the filtrate is washed to obtain a mixture C;

[0012] 4) dry the mixture C to obtain black blended powder D;

[0013] 5) put the black blended powder D into an atmosphere furnace, pyrolyze and reduce in inert gas atmosphere at 400-700℃ for 1-6h to obtain the carbon-based negative electrode additive for lead-carbon battery.

[0014] As a preferred scheme of the present application, the soluble lead salt in step 1) is one or more of lead nitrate and lead acetate.

[0015] As a preferred scheme of the present application, the organic acid in step 2) is citric acid, oxalic acid, tartaric acid, malic acid or amino acid.

[0016] As a preferred scheme of the present application, the molar ratio of the soluble lead salt in the mixed solution A and the organic acid in solution B in step 3) is 1:1.

[0017] As a preferred scheme of the present application, the washing solution in step 3) is pure water or ethanol.

[0018] As a preferred scheme of the present application, the drying temperature in step 4) is 60-100℃, and the drying time is 4-12h.

[0019] As a preferred scheme of the present application, the inert gas flow rate in step 5) is 50-200mL / min -1 , and the temperature rising rate of the atmosphere furnace is 2-5℃ / min -1 .

[0020] As a preferred scheme of the present application, the inert gas in step 5) is one of nitrogen, argon and hydrogen-argon mixed gas.

[0021] The lead loading in the carbon-based negative electrode additive for lead-carbon battery prepared by the above method is 5.0wt.%-50.0wt.%.

[0022] The present application further provides a method for using the carbon-based negative electrode additive for lead-carbon battery obtained by the present application, wherein the prepared carbon-based negative electrode additive for lead-carbon battery is added into the negative lead paste in a weight ratio of (0.2-5):100.

[0023] The present application has the following advantages:

[0024] 1、Compared with the prior art, the complex precipitation method has the characteristics of the immersion precipitation method (controllable preparation of lead content) and the organic matter complex lead pyrolysis method (repeatability and stability). The prepared carbon-based negative electrode additive of lead-carbon battery has the characteristics that the lead particles are uniformly dispersed on the carbon skeleton and the lead and the carbon skeleton are tightly combined by chemical bonds, the controllable preparation of lead loading can be realized, no impurities are introduced, the high specific surface area and porosity of the carbon material can be retained, and the repeatability and stability are excellent.

[0025] 2、The additive avoids the floating carbon phenomenon in the paste mixing process, improves the uniformity of the carbon material in the negative plate, inhibits the hydrogen evolution reaction of the negative plate, and improves the high-rate cycle life.

[0026] 3、The present application is simple, controllable and low in cost, and easy to realize large-scale preparation. BRIEF DESCRIPTION OF DRAWINGS

[0027] Fig. 1 The scanning electron microscope (SEM) photo of the Pb / RHAC-10 sample prepared in the present application.

[0028] Fig. 2 The scanning electron microscope (SEM) photo of the Pb / RHAC-20 sample prepared in the present application.

[0029] Fig. 3 The scanning electron microscope (SEM) photo of the Pb / RHAC-30 sample prepared in the present application.

[0030] Fig. 4 The high-resolution transmission electron microscope (HRTEM) photo of the Pb / RHAC-20 sample prepared in the present application.

[0031] Fig. 5 The linear sweep voltammetry curve comparison diagram of the negative plate of Example 1, Example 2, Example 3, Comparative Example 1 and Comparative Example 2.

[0032] Fig. 6 The high-rate partial state of charge (HRPSoC) cycle life comparison diagram of the negative plate of Example 1, Example 2, Example 3, Comparative Example 1 and Comparative Example 2. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described below in combination with the drawings and implementation examples.

[0034] Example 1:

[0035] 1) 10.20 g of (CH3COO)2Pb»3H2O, 4.40 g of CH3COONa and 50 g of rice husk activated carbon (RHAC) were sequentially added into 1200 mL of purified water to form solution A. 5.60 g of C6H8O7»H2O was dissolved in 300 mL of purified water to form solution B. Solution B was slowly added into solution A under constant stirring at a rate of 1.0 mL min -1 , and the white precipitate was allowed to deposit on the RHAC. After the addition of solution B was completed, the mixture was allowed to stand for 15 min, and then filtered. The filter cake was washed with purified water to form mixture C. Subsequently, mixture C was dried in an oven at 100 °C for 12 h to form black blended powder D. Finally, black powder D was placed in a muffle furnace and pyrolytically reduced in a nitrogen atmosphere at 500 °C for 1 h at a gas flow rate of 50 mL min -1 at a heating rate of 2 °C min -1 to form a carbon-based negative electrode additive for lead-carbon batteries, designated as Pb / RHAC-10.

[0036] 2) Lead powder (100 wt.%, 78% oxidation degree), Pb / RHAC-10 (1.00 wt.%), short fibers (0.13 wt.%), BaS04(0.80 wt.%), sodium lignosulfonate (0.20 wt.%), humic acid (0.20 wt.%), purified water (11.50 wt.%), sulfuric acid (8.80 wt.% with a specific gravity of 1.41 g cm -3 ), were mixed uniformly and coated on a lead-tin-calcium alloy grid to form a negative electrode for lead-carbon batteries after curing and formation.

[0037] Example 2:

[0038] 1) 23.00 g of (CH3COO)2Pb»3H2O, 9.90 g of CH3COONa and 50 g of RHAC were sequentially added into 1200 mL of purified water to form solution A. 12.7 g of C6H8O7»H2O was dissolved in 300 mL of purified water to form solution B. Solution B was slowly added into solution A under constant stirring at a rate of 1.0 mL min -1 , and the white precipitate was allowed to deposit on the RHAC. After the addition of solution B was completed, the mixture was allowed to stand for 15 min, and then filtered. The filter cake was washed with purified water to form mixture C. Subsequently, mixture C was dried in an oven at 100 °C for 12 h to form black blended powder D. Finally, black powder D was placed in a muffle furnace and pyrolytically reduced in a nitrogen atmosphere at 500 °C for 1 h at a gas flow rate of 50 mL min -1 at a heating rate of 2 °C min -1 to form a carbon-based negative electrode additive for lead-carbon batteries, designated as Pb / RHAC-20.

[0039] 2) Lead powder (100 wt.%, oxidation degree 78%), Pb / RHAC-20 (1.00 wt.%), short fiber (0.13 wt.%), BaS04(0.80 wt.%), sodium lignosulfonate (0.20 wt.%), humic acid (0.20 wt.%), pure water (11.50 wt.%), sulfuric acid (8.80 wt.% with specific gravity of 1.41 g cm -3 ), were mixed uniformly and coated on the lead-tin-calcium alloy grid. After curing and formation, a lead-carbon battery negative electrode was obtained.

[0040] Example 3:

[0041] 1) 39.40 g of (CH3COO)2Pb-3H2O, 17.00 g of CH3COONa and 50 g of RHAC were sequentially added into 1200 mL of pure water to form a solution A. 21.80 g of C6H8O7-H2O was dissolved in 300 mL of pure water to form a solution B. Under constant stirring, solution B was slowly added into solution A at a dropping speed of 1.0 mL min -1 , so that the white precipitate separated was deposited on the RHAC. After the addition of solution B was completed, the mixture was allowed to stand for 15 min, and then filtered. The filter was washed with pure water to obtain a mixture C. Subsequently, mixture C was dried in an oven at 100 °C for 12 h to obtain a black blended powder D. Finally, black powder D was placed in an atmosphere furnace and pyrolytic reduction was carried out at 500 °C under nitrogen atmosphere for 1 h at a gas flow rate of 50 mL min -1 and a temperature increasing rate of 2 °C min -1 to obtain a lead-carbon battery carbon-based negative electrode additive, which was named as Pb / RHAC-30.

[0042] 2) Lead powder (100 wt.%, oxidation degree 78%), Pb / RHAC-30 (1.00 wt.%), short fiber (0.13 wt.%), BaS04(0.80 wt.%), sodium lignosulfonate (0.20 wt.%), humic acid (0.20 wt.%), pure water (11.50 wt.%), sulfuric acid (8.80 wt.% with specific gravity of 1.41 g cm -3 ), were mixed uniformly and coated on the lead-tin-calcium alloy grid. After curing and formation, a lead-carbon battery negative electrode was obtained.

[0043] Comparative Example 1:

[0044] Lead powder (100 wt.%, oxidation degree 78%), short fiber (0.13 wt.%), BaS04(0.80 wt.%), sodium lignosulfonate (0.20 wt.%), humic acid (0.20 wt.%), pure water (11.50 wt.%), sulfuric acid (8.80 wt.% with specific gravity of 1.41 g cm -3), which was coated on the lead-tin-calcium alloy grid uniformly, and after solidification and formation, a lead-acid battery negative electrode was obtained.

[0045] Comparative Example 2:

[0046] Lead powder (100 wt.%, oxidation degree 78%), RHAC (1.00 wt.%), short fibers (0.13 wt.%), BaSO4(0.80 wt.%), sodium lignosulfonate (0.20 wt.%), humic acid (0.20 wt.%), pure water (11.50 wt.%), sulfuric acid (8.80 wt.% with a specific gravity of 1.41 g cm -3 ), which was coated on the lead-tin-calcium alloy grid uniformly, and after solidification and formation, a lead-carbon battery negative electrode was obtained.

[0047] Effect of implementation

[0048] Figs. 1-3 SEM images of Pb / RHAC-10, Pb / RHAC-20, and Pb / RHAC-30, respectively, show that the lead particles are uniformly anchored on the surface of the RHAC framework. The average particle size ranges of Pb / RHAC-10, Pb / RHAC-20, and Pb / RHAC-30 are 103.2 ± 28.0 nm, 114.1 ± 25.1 nm, and 136.7 ± 31.6 nm, respectively. As the lead loading increases, the lead particles become more and more dense and agglomerate to form larger particles.

[0049] Fig. 4 The HRTEM image of Pb / RHAC-20, from which the interplanar spacing of 0.286 nm can be clearly observed, corresponds to the (111) plane of the Pb particles, proving the success of the anchoring of the lead particles. It is worth noting that Pb / RHAC-20 is composed of two parts of lead particles and RHAC, and at the interface, it presents a continuous and no obvious gap state. This observation shows that the combination between the lead particles and the RHAC is very tight, and this tight combination is conducive to the transmission of electrons and ions, thereby improving the electrochemical performance of the composite material.

[0050] Fig. 5 The linear sweep voltammetry curve comparison diagram of the negative electrode plates prepared in Examples 1-3, Comparative Example 1, and Comparative Example 2 is shown. At a potential of -1.6 V, we compared the hydrogen evolution current of different electrodes. The hydrogen evolution current of Comparative Example 1 without adding rice husk activated carbon is the smallest (-0.111 A cm -2 ), and the hydrogen evolution current of Comparative Example 2 directly adding rice husk activated carbon is the largest (-0.299 A cm -2), however, the addition of the Pb / RHAC-10, Pb / RHAC-20 and Pb / RHAC-30 of Example 1-3 prepared by the present application, the hydrogen evolution current of the lead carbon battery negative electrode is reduced by 18.4%, 37.5% and 47.5% respectively compared with Comparative Example 2, the hydrogen evolution current of the negative plate is weakened, which proves that the carbon-based negative electrode additive prepared by the present application can effectively inhibit hydrogen evolution and slow down the water loss of the battery.

[0051] Fig. 6 The lead carbon battery negative electrodes of Example 1-3, Comparative Example 1 and Comparative Example 2 are cycled under high rate partial state of charge (HRPSoC) to compare the cycle life. The HRPSoC cycle life of the negative electrodes of Comparative Example 2, Example 1, Example 2 and Example 3 is increased by 2.9 times, 6 times, 10 times and 7.8 times respectively compared with the negative electrode of Comparative Example 1. The carbon-based negative electrode additive prepared by the present application can greatly improve the HRPSoC cycle life of the lead-acid battery and also can significantly inhibit the hydrogen evolution of the lead carbon battery negative electrode and alleviate the problem caused by irreversible sulfation.

[0052] It should be noted that the above examples are only used to illustrate the present application and not used to limit the scope of the present application. In addition, it should be understood that after reading the content taught by the present application, those skilled in the art can make various modifications or changes to the present application, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

Claims

1. A controllable preparation method of carbon-based negative electrode additives for lead-carbon batteries, characterized in that, The method comprises the following steps: 1) mixing soluble lead salt, sodium acetate and carbon-based material in pure water to obtain a mixed solution A; the concentration of the soluble lead salt in the mixed solution A is 0.01 mol / L -1 ~0.10 mol / L -1 , the concentration of sodium acetate is 0.05 mol / L -1 ~0.10 mol / L -1 , and the concentration of the carbon-based material is 0.2 g / mL -1 ~1.0 g / mL -1 ; The carbon-based material includes one or more of activated carbon, carbon black, expanded graphite, graphene, carbon nanotube, carbon fiber, and has a specific surface area of 20m 2 g -1 ~2000m 2 g -1 , and a particle size D90 of 20nm~150μm. 2) preparing an organic acid solution B having a concentration of 0.01 mol L -1 ~ 0.10 mol L -1 of one or more of the organic acids capable of complexing with lead ions to form a precipitate; 3) Solution B was added to the mixed solution A at a rate of 0.5 mL min -1 ~ 5.0 mL min -1 The white precipitate that separated out was deposited on the carbon-based material, and after standing, the mixture was filtered. The filtrate was washed to obtain mixture C. 4) drying the mixture C to obtain a black blended powder D; 5) placing the black blended powder D in an atmosphere furnace, pyrolyzing and reducing in an inert gas atmosphere at a temperature of 400-700°C for 1-6h to obtain a carbon-based negative electrode additive for lead-carbon batteries.

2. The process for the controllable preparation of carbon-based negative electrode additives for lead-carbon batteries according to claim 1, characterized in that, The soluble lead salt in step 1) is one or more of lead nitrate and lead acetate.

3. The process for the controllable preparation of carbon-based negative electrode additives for lead-carbon batteries according to claim 1, characterized in that, The organic acid in step 2) is citric acid, oxalic acid, tartaric acid, malic acid or an amino acid.

4. The process for the controllable preparation of carbon-based negative additives for lead-carbon batteries according to claim 1, characterized by the fact that, The molar ratio of the soluble lead salt in the mixed solution A and the organic acid in solution B in step 3) is 1:

1.

5. The process for the controllable preparation of carbon-based negative additives for lead-carbon batteries according to claim 1, characterized by the fact that, The washing solution in step 3) is pure water or ethanol.

6. The process for the controllable production of carbon-based negative electrode additives for lead-carbon batteries according to claim 1, characterized in that, The drying temperature in step 4) is 60-100°C, and the drying time is 4-12h.

7. The process for the controllable production of carbon-based negative electrode additives for lead-carbon batteries according to claim 1, characterized in that, The inert gas flow rate in step 5) is 50-200 mL min -1 The atmosphere furnace heating rate is 2-5 °C min -1 .

8. The process for the controllable production of carbon-based negative electrode additives for lead-carbon batteries according to claim 1, characterized in that, The inert gas in step 5) is one of nitrogen, argon and hydrogen-argon mixed gas.

9. A carbon-based negative electrode additive for lead-carbon batteries, obtainable by the process according to any one of claims 1 to 8, characterized by the fact that, The lead loading of the carbon-based negative electrode additive for lead-carbon batteries is 5.0-50.0wt.%.

10. Use of a carbon-based negative electrode additive for lead-carbon batteries according to claim 9, characterized in that, The prepared carbon-based negative electrode additive for lead-carbon batteries is added to the negative lead paste in a weight ratio, wherein the weight ratio of the carbon-based negative electrode additive for lead-carbon batteries to lead powder is (0.2-5):100.

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