Preparation method of composite PbO / ZnO three-dimensional porous lead-carbon battery additive

Abstract

This invention relates to a method for preparing a composite PbO / ZnO three-dimensional porous lead-carbon battery additive, belonging to the field of lead-carbon battery technology. The invention involves pre-treating a titanium substrate by degreasing, followed by etching and activation in a nitric acid-hydrochloric acid mixture to obtain an activated titanium substrate. A three-dimensional hierarchical porous carbon, carbon black, and PVDF binder are mixed uniformly to obtain a mixture. N-pyrrolidone is added to the mixture, and the mixture is further mixed uniformly to obtain a three-dimensional hierarchical porous carbon slurry. The three-dimensional hierarchical porous carbon slurry is uniformly coated onto the surface of the activated titanium substrate and dried to obtain a carbon-based anode. Using a lead nitrate-zinc oxide mixed solution as the electroplating solution, the carbon-based anode is used as the anode, and a copper plate as the cathode. Electroplating is performed at 40–50°C with stirring for 1–2 hours. After electroplating, the anode is removed, washed with deionized water, and the electroplated layer is scraped off the titanium substrate surface and vacuum dried to obtain the composite PbO / ZnO three-dimensional porous lead-carbon battery additive. In this invention, PbO / ZnO is uniformly modified on the three-dimensional hierarchical porous carbon material, which, as a lead-carbon battery additive, can effectively inhibit the hydrogen evolution reaction.

Description

Technical Field

[0001] This invention relates to a method for preparing a composite PbO / ZnO three-dimensional porous lead-carbon battery additive, belonging to the field of lead-carbon battery technology. Background Technology

[0002] Lead-acid batteries have advantages such as low price, high safety performance, wide application, and high recyclability. In recent years, lead-acid batteries have been considered one of the most widely used power sources in transportation. However, the widespread application of traditional lead-acid batteries is greatly limited by their many drawbacks, including low specific energy, large footprint, short cycle life, and poor rate performance. In particular, under high-rate partial state of charge (HRPSoC) charge-discharge conditions, the negative electrode of lead-acid batteries is prone to irreversible sulfation of the active material, leading to a decline in lifespan and capacity.

[0003] Lead-carbon batteries (LCBs) are a new type of battery developed by incorporating carbon materials into lead-acid battery designs. They combine the advantages of supercapacitors, such as instantaneous high-capacity charging, high charging capacity, excellent rate performance, and long cycle life at high rates, and are widely used in emerging fields such as hybrid electric vehicles and wind and solar energy storage. However, the addition of carbon materials still presents several problems when fully charged at high rates: carbon materials have a low hydrogen evolution overpotential, and under high-rate conditions, the electrodes are prone to severe hydrogen evolution reactions. The evolution of hydrogen gas can damage the structural stability of the electrodes, reducing the cycle stability of the battery. Current solutions to these problems include:

[0004] (1) Functionalizing carbon materials by modifying heteroatoms with higher electronegativity than C atoms to make the carbon ends positively charged, thereby suppressing hydrogen evolution. However, the source materials for heteroatoms are all organic compounds such as pyridine and pyrrole, which will cause environmental pollution.

[0005] (2) Directly adding metals and their oxides with high hydrogen evolution overpotentials can easily lead to carbon floating. This is because the bond between the metal and the carbon material is unstable and is formed through physical interactions.

[0006] (3) Adding lead-carbon composites. Lead-carbon composites are currently widely studied because Pb and its oxides are the active substances in lead-carbon composites and do not introduce impurity ions. At the same time, lead-carbon composites have a stable structure and can effectively solve the problem of carbon floating. However, there are still problems such as uneven distribution of metallic lead and its oxides in carbon materials, easy agglomeration, and difficulty in controlling the particle size of hydrogen evolution inhibitors. Summary of the Invention

[0007] To address the issue of low hydrogen evolution overpotential in existing lead-carbon batteries (LCBs), which easily leads to severe hydrogen evolution reactions at high-rate charge and discharge conditions, and the resulting hydrogen evolution damages the structural stability of the electrode, thus reducing the cycle stability of the LCB, this invention proposes a method for preparing a composite PbO / ZnO three-dimensional porous LCB additive. This invention prepares the composite PbO / ZnO three-dimensional porous LCB additive via electroplating, with PbO / ZnO uniformly modified on the three-dimensional hierarchical porous carbon material. As an additive for LCBs, it effectively inhibits the hydrogen evolution reaction, significantly improving the cycle life and initial discharge capacity at high rates. It avoids the problems of PbO agglomeration on the three-dimensional hierarchical porous carbon, difficulty in controlling particle size, and low activity of single PbO hydrogen evolution inhibitors. This solves the problems of poor rate performance and cycle life, and low initial capacity performance in LCBs.

[0008] A method for preparing a composite PbO / ZnO three-dimensional porous lead-carbon battery additive, the specific steps of which are as follows:

[0009] (1) The titanium base is pretreated by degreasing and then etched and activated in a nitric acid-hydrochloric acid mixture to obtain activated titanium base;

[0010] (2) Three-dimensional hierarchical porous carbon, carbon black and PVDF binder are mixed evenly to obtain a mixture. N-pyrrolidone is added to the mixture and mixed evenly to obtain a three-dimensional hierarchical porous carbon slurry. The three-dimensional hierarchical porous carbon is prepared by self-templating and chemical activation method.

[0011] (3) The three-dimensional hierarchical porous carbon slurry is uniformly coated on the activated titanium-based surface and dried to obtain a carbon-based anode;

[0012] (4) Using a lead nitrate-zinc oxide mixed solution as the electroplating solution, a carbon-based anode as the anode, and a copper plate as the cathode, electroplating was carried out at a temperature of 40-50℃ with stirring for 1-2 hours. After electroplating, the anode was removed, washed with deionized water, and the electroplated layer was scraped off from the titanium-based surface and vacuum dried to obtain the composite PbO / ZnO three-dimensional porous lead-carbon battery additive. In the composite PbO / ZnO three-dimensional porous lead-carbon battery additive, PbO / ZnO is uniformly modified on the three-dimensional hierarchical porous carbon material, which improves the electrocatalytic activity and uniformity of the single hydrogen evolution inhibitor PbO modification. As a lead-carbon battery additive, it can effectively inhibit the hydrogen evolution reaction and significantly improve the cycle life and initial discharge capacity of the battery under high charge rate.

[0013] The method of degreasing pretreatment in step (1) is as follows: the titanium base is successively sanded with sandpaper and degreased with an alkaline degreasing agent.

[0014] Preferably, the alkaline degreasing agent contains 40-50 g / L of trisodium phosphate (Na3PO4), 15-20 g / L of sodium silicate (Na2SiO3), has a pH value of 8-10, a degreasing temperature of 50-60°C, and a degreasing time of 1-3 min.

[0015] In step (1), the nitric acid concentration in the nitric acid-hydrochloric acid mixture is 0.1–0.3 mol / L, and the hydrochloric acid concentration is…

[0016] 0.3–0.6 mol / L; etching activation time is 60–80 s.

[0017] Based on the mass fraction of the mixture in step (2) being 100%, the three-dimensional hierarchical porous carbon accounts for 70-80%, carbon black accounts for 10-15%, and the binder PVDF accounts for 10-15%; the amount of N-pyrrolidone added is 10-15% of the mass of the mixture.

[0018] The preparation method of three-dimensional hierarchical porous carbon in step (2) is as follows:

[0019] 1) The carbonized biochar was etched in NaOH solution, washed successively with hydrochloric acid and deionized water, and then vacuum dried to obtain etched biochar;

[0020] 2) Mix the etched biochar with the activator, then place it in a tube furnace, heat it at a constant rate to 700-800℃ under a nitrogen atmosphere and keep it at that temperature for 1-2 hours, cool it to room temperature, wash it and vacuum dry it to obtain three-dimensional hierarchical porous carbon.

[0021] Preferably, in step 1), the NaOH solution has a mass concentration of 10-15%, the etching temperature is 60-90℃, the etching time is 2-2.5h, and the hydrochloric acid has a mass concentration of 10-15%.

[0022] Preferably, in step 2), the mass ratio of etched biochar to activator is 1:3 to 5; and the heating rate is 5 to 10 °C / min.

[0023] In step (3), the loading of three-dimensional hierarchical porous carbon on the carbon-based anode surface is 2.5–3.0 mg / cm³. 2 .

[0024] In step (4), the concentration of lead nitrate in the electroplating solution is 190-250 g / L, the concentration of zinc oxide is 12-20 g / L, and the pH value of the electroplating solution is 6-8.

[0025] Preferably, the zinc oxide particle size is 50-60 nm.

[0026] In step (4), the anolyte current density for electroplating is 2-4 A / dm³. 2 The stirring rate is 250–320 r / min.

[0027] The principle behind the composite PbO / ZnO three-dimensional porous lead-carbon battery additive's ability to effectively suppress hydrogen evolution reaction and delay irreversible sulfation of the negative electrode is as follows: The PbO / ZnO composite on the carbon material increases the hydrogen evolution overpotential, requiring greater energies for the hydrogen evolution reaction to occur, thus making the reaction less likely to happen. The composite PbO / ZnO three-dimensional porous lead-carbon battery additive provides a double-layer effect; PbO / ZnO provides pseudocapacitance, effectively suppressing irreversible sulfation.

[0028] The beneficial effects of this invention are:

[0029] (1) The composite PbO / ZnO three-dimensional porous lead-carbon battery additive prepared by electroplating method in this invention has PbO / ZnO uniformly modified on three-dimensional hierarchical porous carbon material, which improves the electrocatalytic activity and uniformity of single hydrogen evolution inhibitor PbO modification, and avoids problems such as PbO agglomeration on porous carbon, difficulty in controlling particle size, and low activity of single PbO hydrogen evolution inhibitor.

[0030] (2) As an additive for lead-carbon batteries, this invention can effectively inhibit hydrogen evolution reaction, delay irreversible sulfation of the negative electrode, and significantly improve the cycle life and initial discharge capacity of the battery under high charge rate. Attached Figure Description

[0031] Figure 1 Here is a SEM image of the composite PbO / ZnO three-dimensional porous lead-carbon battery additive from Example 1.

[0032] Figure 2 EDS image of the composite PbO / ZnO three-dimensional porous lead-carbon battery additive in Example 2;

[0033] Figure 3 The image shows the XRD pattern of the composite PbO / ZnO three-dimensional porous lead-carbon battery additive in Example 3.

[0034] Figure 4 The initial discharge specific capacity of the battery prepared using the composite PbO / ZnO three-dimensional porous lead-carbon battery additive in Example 1;

[0035] Figure 5 The high-rate cycle life diagram is shown for the battery prepared using the composite PbO / ZnO three-dimensional porous lead-carbon battery additive in Example 1. Detailed Implementation

[0036] The present invention will be further described in detail below with reference to specific embodiments, but the scope of protection of the present invention is not limited to the content described.

[0037] Example 1: A method for preparing a composite PbO / ZnO three-dimensional porous lead-carbon battery additive, the specific steps of which are as follows:

[0038] (1) The titanium substrate was sanded with sandpaper, placed in an alkaline degreasing agent, and pretreated for 2 minutes at 50°C. Then it was placed in a nitric acid-hydrochloric acid mixture and etched and activated at room temperature for 60 seconds to obtain an activated titanium substrate. The alkaline degreasing agent contained 40 g / L of trisodium phosphate (Na3PO4) and 15 g / L of sodium silicate (Na2SiO3), with a pH of 8. The nitric acid-hydrochloric acid mixture had a nitric acid concentration of 0.3 mol / L and a hydrochloric acid concentration of 0.3 mol / L.

[0039] (2) Three-dimensional hierarchical porous carbon, carbon black, and binder PVDF are mixed evenly to obtain a mixture. N-pyrrolidone is added to the mixture and mixed evenly to obtain a three-dimensional hierarchical porous carbon slurry. The mixture comprises 70% three-dimensional hierarchical porous carbon, 15% carbon black, and 15% binder PVDF, with the mass fraction of the mixture being 100%. The amount of N-pyrrolidone added is 10% of the mass of the mixture.

[0040] The three-dimensional hierarchical porous carbon was prepared using a self-templating and chemical activation method, and the specific steps are as follows:

[0041] 1) Carbonized corn stalk biochar was placed in a 10% NaOH solution and etched at 80°C for 2 hours. The NaOH was removed by washing with 15% hydrochloric acid and then washed with deionized water until the washing solution was neutral. The etched biochar was obtained by vacuum drying.

[0042] 2) The etched biochar and activator (KOH) were mixed evenly and then placed in a tube furnace. Under a nitrogen atmosphere, the temperature was uniformly increased to 700℃ at a heating rate of 5℃ / min and held for 10h. Then, the temperature was uniformly decreased to room temperature at a cooling rate of 5℃ / min. The activator (KOH) was removed by washing with 15% hydrochloric acid, and then washed with deionized water until the washing solution was neutral. The three-dimensional hierarchical porous carbon was obtained by vacuum drying. The mass ratio of etched biochar to activator (KOH) was 1:3.

[0043] (3) A three-dimensional hierarchical porous carbon slurry is uniformly coated on the activated titanium-based surface and dried at 65°C to obtain a carbon-based anode; the loading of the three-dimensional hierarchical porous carbon on the surface of the carbon-based anode is 3.0 mg / cm³. 2 ;

[0044] (4) Using a lead nitrate-zinc oxide mixed solution as the electroplating solution, a carbon-based anode as the anode, and a copper plate as the cathode, electroplating was performed at 40–50°C with stirring for 2–2.5 hours. After electroplating, the anode was removed, washed with deionized water, and the electroplated layer was scraped off from the titanium-based surface and vacuum dried to obtain the composite PbO / ZnO three-dimensional porous lead-carbon battery additive. In the composite PbO / ZnO three-dimensional porous lead-carbon battery additive, PbO / ZnO is uniformly modified on the three-dimensional hierarchical porous carbon material (see Appendix). Figure 1 This process enhances the electrocatalytic activity and uniformity of PbO modification, a single hydrogen evolution inhibitor. As an additive for lead-carbon batteries, it effectively suppresses the hydrogen evolution reaction, significantly improving cycle life and initial discharge capacity under high charge rates. The electroplating solution contains 190 g / L lead nitrate, 20 g / L zinc oxide, and has a pH of 6. The zinc oxide particle size is 55–58 nm. The anolyte current density during electroplating is 2.0 A / dm³. 2 The stirring rate is 260 r / min;

[0045] The SEM image of the composite PbO / ZnO three-dimensional porous lead-carbon battery additive in this embodiment is attached. Figure 1 SEM images were used to characterize the morphology of the composite PbO / ZnO three-dimensional porous lead-carbon battery additive. Fine white particles appeared on the three-dimensional porous carbon material of the composite PbO / ZnO additive in the SEM, indicating that PbO / ZnO was successfully composited on the three-dimensional porous carbon material.

[0046] Example 2: A method for preparing a composite PbO / ZnO three-dimensional porous lead-carbon battery additive, the specific steps of which are as follows:

[0047] (1) The titanium substrate was sanded with sandpaper, placed in an alkaline degreasing agent, and pretreated for degreasing at 55°C for 1.5 min. Then it was placed in a nitric acid-hydrochloric acid mixture and etched and activated at room temperature for 70 s to obtain activated titanium substrate. The alkaline degreasing agent contained 45 g / L of trisodium phosphate (Na3PO4) and 18 g / L of sodium silicate (Na2SiO3), with a pH of 9. The nitric acid-hydrochloric acid mixture had a nitric acid concentration of 0.2 mol / L and a hydrochloric acid concentration of 0.4 mol / L.

[0048] (2) Three-dimensional hierarchical porous carbon, carbon black, and binder PVDF are mixed evenly to obtain a mixture. N-pyrrolidone is added to the mixture and mixed evenly to obtain a three-dimensional hierarchical porous carbon slurry. The mixture comprises 75% three-dimensional hierarchical porous carbon, 10% carbon black, and 15% binder PVDF, with the mass fraction of the mixture being 100%. The amount of N-pyrrolidone added is 12% of the mass of the mixture.

[0049] The three-dimensional hierarchical porous carbon was prepared using a self-templating and chemical activation method, and the specific steps are as follows:

[0050] 1) Carbonized corn stalk biochar was placed in a 12% NaOH solution and etched at 70°C for 2.5 hours. The NaOH was removed by washing with 10% hydrochloric acid and then washed with deionized water until the washing solution was neutral. The etched biochar was then obtained by vacuum drying.

[0051] 2) The etched biochar and activator (KOH) were mixed evenly and then placed in a tube furnace. Under a nitrogen atmosphere, the temperature was uniformly increased to 750℃ at a heating rate of 8℃ / min and held for 1.4h. Then, the temperature was uniformly decreased to room temperature at a cooling rate of 8℃ / min. The activator (KOH) was removed by washing with 12% hydrochloric acid, and then washed with deionized water until the washing solution was neutral. The three-dimensional hierarchical porous carbon was obtained by vacuum drying. The mass ratio of etched biochar to activator (KOH) was 1:3.

[0052] (3) A three-dimensional hierarchical porous carbon slurry is uniformly coated on the activated titanium-based surface and dried at 75°C to obtain a carbon-based anode; the loading of the three-dimensional hierarchical porous carbon on the surface of the carbon-based anode is 2.8 mg / cm³. 2 ;

[0053] (4) Using a lead nitrate-zinc oxide mixed solution as the electroplating solution, a carbon-based anode as the anode, and a copper plate as the cathode, electroplating was performed at 48℃ with stirring for 1.9 h. After electroplating, the anode was removed, washed with deionized water, and the electroplated layer was scraped off from the titanium-based surface and vacuum dried to obtain a composite PbO / ZnO three-dimensional porous lead-carbon battery additive. In the composite PbO / ZnO three-dimensional porous lead-carbon battery additive, PbO / ZnO is uniformly modified on the three-dimensional hierarchical porous carbon material, which improves the electrocatalytic activity and uniformity of the single hydrogen evolution inhibitor PbO modification. As a lead-carbon battery additive, it can effectively inhibit the hydrogen evolution reaction and significantly improve the cycle life and initial discharge capacity of the battery under high charge rate. The concentration of lead nitrate in the electroplating solution was 220 g / L, the concentration of zinc oxide was 15 g / L, the pH value of the electroplating solution was 8, and the particle size of zinc oxide was 50-55 nm. The anode current density of electroplating was 3.0 A / dm³. 2 The stirring rate is 285 r / min;

[0054] The EDS diagram of the composite PbO / ZnO three-dimensional porous lead-carbon battery additive in this embodiment is attached. Figure 2 The presence of Pb and Zn in the EDS diagram of the composite PbO / ZnO three-dimensional porous lead-carbon battery additive indicates that PbO / ZnO is co-composite to the carbon material.

[0055] Example 3: A method for preparing a composite PbO / ZnO three-dimensional porous lead-carbon battery additive, the specific steps of which are as follows:

[0056] (1) The titanium substrate is sanded with sandpaper, placed in an alkaline degreasing agent, and pre-treated for degreasing at a temperature of 60-80℃ for 1-2 minutes. Then it is placed in a nitric acid-hydrochloric acid mixture and etched and activated at room temperature for 80-85 seconds to obtain activated titanium substrate. The alkaline degreasing agent contains 50 g / L of trisodium phosphate (Na3PO4) and 20 g / L of sodium silicate (Na2SiO3), with a pH value of 10. The nitric acid concentration in the nitric acid-hydrochloric acid mixture is 0.3 mol / L, and the hydrochloric acid concentration is 0.6 mol / L.

[0057] (2) Three-dimensional hierarchical porous carbon, carbon black, and binder PVDF are mixed evenly to obtain a mixture. N-pyrrolidone is added to the mixture and mixed evenly to obtain a three-dimensional hierarchical porous carbon slurry. Among them, based on the mass fraction of the mixture as 100%, the three-dimensional hierarchical porous carbon accounts for 72%, carbon black accounts for 15%, and binder PVDF accounts for 13%. The amount of N-pyrrolidone added is 15% of the mass of the mixture.

[0058] The three-dimensional hierarchical porous carbon was prepared using a self-templating and chemical activation method, and the specific steps are as follows:

[0059] 1) Carbonized corn stalk biochar was placed in a 10% NaOH solution and etched at 90°C for 2.5 hours. The NaOH was removed by washing with 12% hydrochloric acid and then washed with deionized water until the washing solution was neutral. The etched biochar was then obtained by vacuum drying.

[0060] 2) The etched biochar and activator (KOH) were mixed evenly and then placed in a tube furnace. Under a nitrogen atmosphere, the temperature was uniformly increased to 800℃ at a heating rate of 10℃ / min and held for 1 hour. Then, the temperature was uniformly decreased to room temperature at a cooling rate of 10℃ / min. The activator (KOH) was removed by washing with 15% hydrochloric acid, and then washed with deionized water until the washing solution was neutral. The three-dimensional hierarchical porous carbon was obtained by vacuum drying. The mass ratio of etched biochar to activator (KOH) was 1:3.

[0061] (3) A three-dimensional hierarchical porous carbon slurry is uniformly coated on the activated titanium-based surface and dried at 80–85°C to obtain a carbon-based anode; the loading of the three-dimensional hierarchical porous carbon on the surface of the carbon-based anode is 2.8 mg / cm³. 2 ;

[0062] (4) Using a lead nitrate-zinc oxide mixed solution as the electroplating solution, a carbon-based anode as the anode, and a copper plate as the cathode, electroplating was performed at 60℃ with stirring for 1.3 hours. After electroplating, the anode was removed, washed with deionized water, and the electroplated layer was scraped off from the titanium-based surface and vacuum dried to obtain a composite PbO / ZnO three-dimensional porous lead-carbon battery additive. In the composite PbO / ZnO three-dimensional porous lead-carbon battery additive, PbO / ZnO is uniformly modified on the three-dimensional hierarchical porous carbon material, which improves the electrocatalytic activity and uniformity of the single hydrogen evolution inhibitor PbO modification. As a lead-carbon battery additive, it can effectively inhibit the hydrogen evolution reaction and significantly improve the cycle life and initial discharge capacity of the battery under high charge rate. The concentration of lead nitrate in the electroplating solution was 240 g / L, the concentration of zinc oxide was 18 g / L, the pH value of the electroplating solution was 7, and the particle size of zinc oxide was 55-60 nm. The anode current density of electroplating was 5.0 A / dm³. 2 The stirring rate is 320 r / min;

[0063] The XRD pattern of the composite PbO / ZnO three-dimensional porous lead-carbon battery additive of this embodiment is attached. Figure 3 XRD patterns of composite PbO / ZnO three-dimensional porous additives, such as Figure 3 As shown, compared with standard cards PDF#30-1451 and PDF#03-0600, the composite PbO / ZnO three-dimensional porous additive shows the typical peak of ZnO on the 101 crystal plane and the typical peak of PbO on the 111, 002 and 201 crystal planes, which further indicates that PbO / ZnO has been successfully modified on the three-dimensional porous carbon material.

[0064] Composite PbO / ZnO three-dimensional porous composite material as an additive for battery performance

[0065] The preparation process of negative electrode lead paste is as follows: A mixture A is prepared by grinding a composite PbO / ZnO three-dimensional porous composite material (2% by weight of lead powder), short fibers (0.05% by weight of lead powder), BaSO4 (0.4% by weight of lead powder), and humic acid (0.7% by weight of lead powder) uniformly in an agate mortar. Then, lead powder (75% oxidation degree) is added to mixture A and thoroughly mixed to obtain mixture B. H2O (12.5 wt.% by weight of lead powder) is slowly added to the mortar using a dropper and stirred thoroughly. Finally, an H2SO4 solution (12.5 wt.% by weight of lead powder, specific gravity of H2SO4 solution 1.25 g·cm³) is added. -3 Add the lead paste slowly and evenly to the mortar in three batches, stirring constantly. Finally, add an appropriate amount of water to adjust the density of the lead paste to 4.2–4.5 g·cm³. -3 ;

[0066] 27.0g of the lead paste prepared above was applied to an area of ​​40×69×2cm. 2On a Pb-Sn-Ca grid; then the manually coated plates were placed on H2SO4 (1.25 g·cm³). -3 The plates were immersed in a solution for 5 seconds. The prepared plates were then placed in a constant temperature and humidity chamber for curing. The curing conditions were: 60℃, 98% humidity, 12h; 75℃, 80% humidity, 24h; 80℃, 0% humidity, 12h. After curing and drying, the negative and positive plates were combined to form a "two positive, one negative" battery. A 2mm AGM separator was used to assemble the battery, and it was then heated in H2SO4 (1.05g·cm³). -3 The formation is carried out in solution;

[0067] To investigate the effect of additives on battery performance under HRPSoC cycling conditions, the performance differences of batteries under micro-hybrid driving conditions were simulated in the laboratory. The process conditions were set as follows: the battery with 0% state of charge was charged to the cutoff voltage of 2.4V with a current of 0.1C, then charged at a constant voltage of 2.4V for 12 hours, and rested for 10 minutes; then discharged at a current of 1C to 50% SoC; finally, high-rate charge-discharge cycles were performed, with the following cycle sequence: charging at 1C and 2C currents for 30 seconds, resting for 10 seconds, discharging at 1C and 2C currents for 30 seconds, and resting for 10 seconds; the voltages at both ends of the battery were recorded during the charge-discharge cycles, and the battery was defined as failing when the discharge voltage reached the cutoff voltage of 1.75V or the charging voltage reached the cutoff voltage of 2.9V; all cycle life tests were repeated at least three times to ensure the reliability of the experimental results; all tests were conducted at room temperature (~25℃); the cycle life curve is the change curve of the charge-discharge termination voltage of the battery for each cycle with the cycle period, and the charge-discharge curve is the change curve of the charge-discharge voltage of the battery with the charge-discharge time;

[0068] The initial discharge specific capacity and high-rate cycle life of the battery in Example 1 are shown in the graphs below. Figures 4-5 ,like Figure 4 As shown in the initial discharge specific capacity of the battery, the composite PbO / ZnO three-dimensional porous composite material, used as an additive for the negative electrode of the lead-carbon battery, effectively improved the initial discharge specific capacity of the battery, from 84 mAh / g of the blank electrode. -1 Increased to 147mAh.g -1This is due to the parallel energy storage mechanism of the lead-carbon electrode, consisting of the Faraday reaction energy storage of lead and the double-layer capacitance energy storage of porous carbon materials. In HRPSoC cycling mode, the activated carbon with a large specific surface area forms a large-area electronic double layer, which can rapidly store electrons and protons. In the initial stage of HRPSoC charging, the capacitive carbon material acts as a power buffer, receiving most of the instantaneous current. As charging time increases, the capacitor is fully charged, and the external circuit provides more and more electrons for the conversion of PbSO4 to Pb, eventually resulting in zero current flowing through the non-Faraday portion. When charging is complete, the external circuit no longer provides electrons. At this point, the electronic double layer stored on the surface of the capacitive carbon material releases electrons and continues the reaction on the electrode surface for a certain period. The high-rate cycle life of the battery is described in [link to battery specifications]. Figure 5 When composite PbO / ZnO three-dimensional porous polymers are used as additives, the high-rate cycle life of the battery reaches 2853 cycles, while the high-rate cycle life of the blank battery is 888 cycles; the high-rate cycle life of the composite PbO / ZnO three-dimensional porous polymer battery is 3.2 times that of the blank battery.

[0069] The specific embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A method for preparing a composite PbO / ZnO three-dimensional porous lead-carbon battery additive, characterized in that, The specific steps are as follows: (1) The titanium base is pretreated by degreasing and then etched and activated in a nitric acid-hydrochloric acid mixture to obtain activated titanium base; (2) Mix three-dimensional graded porous carbon, carbon black and binder PVDF evenly to obtain a mixture, add N-pyrrolidone to the mixture and mix evenly to obtain three-dimensional graded porous carbon slurry; (3) The three-dimensional hierarchical porous carbon slurry is uniformly coated on the activated titanium-based surface and dried to obtain a carbon-based anode; (4) Using a mixed solution of lead nitrate and zinc oxide as the electroplating solution, a carbon-based anode as the anode and a copper plate as the cathode, electroplating is carried out at a temperature of 40~50℃ and under stirring conditions for 1~2 hours. The electroplated anode is taken out, cleaned with deionized water, and the electroplated layer is scraped off from the titanium-based surface and vacuum dried to obtain the composite PbO / ZnO three-dimensional porous lead-carbon battery additive. In step (1), the concentration of nitric acid in the nitric acid-hydrochloric acid mixture is 0.1~0.3 mol / L, and the concentration of hydrochloric acid is 0.3~0.6 mol / L; the immersion activation time is 60~80 s. Based on the mass fraction of the mixture in step (2) being 100%, the three-dimensional hierarchical porous carbon accounts for 70-80%, carbon black accounts for 10-15%, and the binder PVDF accounts for 10-15%; the amount of N-pyrrolidone added is 10-15% of the mass of the mixture. The preparation method of three-dimensional hierarchical porous carbon in step (2) is as follows: 1) The carbonized biochar was etched in NaOH solution, washed successively with hydrochloric acid and deionized water, and then vacuum dried to obtain etched biochar; 2) Mix the etched biochar with the activator, then place it in a tube furnace, heat it at a constant rate to 700~800℃ under a nitrogen atmosphere and keep it at that temperature for 1~2 hours, cool it to room temperature, wash it and vacuum dry it to obtain three-dimensional hierarchical porous carbon. In step 1), the NaOH solution has a mass concentration of 10-15%, the etching temperature is 60-90℃, the etching time is 2-2.5h, and the hydrochloric acid has a mass concentration of 10-15%. In step 2), the activator is KOH; the mass ratio of the etched biochar to the activator is 1:3~5; and the heating rate is 5~10℃ / min.

2. The preparation method of the composite PbO / ZnO three-dimensional porous lead-carbon battery additive according to claim 1, characterized in that: Step (3): The loading of three-dimensional hierarchical porous carbon on the carbon-based anode surface is 2.5~3.0 mg / cm³. 2 .

3. The preparation method of the composite PbO / ZnO three-dimensional porous lead-carbon battery additive according to claim 1, characterized in that: Step (4) The concentration of lead nitrate in the electroplating solution is 190~250g / L, the concentration of zinc oxide is 12~20g / L, and the pH value of the electroplating solution is 6~8.

4. The preparation method of the composite PbO / ZnO three-dimensional porous lead-carbon battery additive according to claim 3, characterized in that: The zinc oxide particle size is 50~60nm.

5. The preparation method of the composite PbO / ZnO three-dimensional porous lead-carbon battery additive according to claim 1, characterized in that: In step (4), the anolyte current density for electroplating is 2~4 A / dm³. 2 The stirring rate is 250~320 r / min.

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