Graded porous carbon negative electrode material with nano-metal synergistic activity and application of graded porous carbon negative electrode material in long-life lead-carbon battery

Abstract

The invention relates to the technical field of lead-acid batteries and novel electrochemical energy storage materials, in particular to a graded porous carbon negative electrode material with nano-metal synergistic activity and application of the graded porous carbon negative electrode material in a long-life lead-carbon battery. The material takes hierarchical pore structure carbon as a matrix (which has micropores, mesopores and macropores at the same time, and the specific surface area reaches 1000m < 2 > / g), and is uniformly loaded with nano metal particles (such as Fe, Co, Sn and the like with the particle size of lt; and the content is 1%-10%). By optimizing the carbon pore structure and introducing the nano-metal, sulfation is remarkably inhibited, the capacitance effect is enhanced, and the hydrogen evolution reaction is reduced, so that the cycle life of the lead-acid battery is prolonged, and the charge-discharge performance of the lead-acid battery is improved. The preparation method is simple and controllable, is suitable for a lead-acid battery negative electrode additive, can be widely applied to the fields of start-stop batteries, energy storage systems and the like, and has important industrial application value.

Description

Technical Field

[0001] This invention relates to the field of lead-acid batteries and novel electrochemical energy storage materials, particularly a hierarchical porous carbon anode material with synergistic activity of nano-metals and its application in long-life lead-carbon batteries. As an anode additive for lead-acid batteries, this material can effectively alleviate sulfation, improve capacitance, and suppress hydrogen evolution, thereby significantly extending battery cycle life. Background Technology

[0002] Lead-acid batteries are widely used in transportation and energy storage due to their low cost and reliability. However, traditional lead-acid batteries are prone to severe sulfation failure at the negative electrode when repeatedly charged and discharged in a partially charged state of charge (PSoC). Specifically, lead sulfate crystals generated during discharge gradually grow and cover the surface of the negative electrode active material, leading to a decrease in reversible capacity, poor charge acceptance, and a significant reduction in battery cycle life. Typically, the cycle life of stationary lead-acid batteries is only about 300 cycles, while automotive batteries have a cycle life of only 500 to 800 cycles. To alleviate the sulfation problem, researchers have attempted to add porous, high-specific-surface-area carbon materials to the negative electrode formulation, thus developing lead-carbon batteries. Carbon materials, by providing more reaction interfaces and constructing a conductive network, can effectively suppress lead sulfate accumulation, delay negative electrode sulfation, and thus significantly improve battery cycle life. Experiments show that adding appropriate amounts of carbon materials such as carbon black to the lead paste of the negative electrode in lead-acid batteries can significantly reduce lead sulfate accumulation under high-rate partially charged (HRPSoC) conditions, thereby greatly improving the cycle life of the battery. For example, research by Furukawa Electric Corporation of Japan shows that by increasing the carbon additive content of the negative electrode, the cycle life under HRPSoC conditions can be increased several times. Lead-carbon batteries are therefore called "hybrids" or "capacitor-type lead-acid batteries," possessing the characteristics of both secondary batteries and electrochemical double-layer capacitors. During instantaneous high-current charging and discharging, carbon materials can bear the main current impact, reducing sulfation and mechanical stress on the lead negative electrode. Their cycle life can be increased by up to 6 times compared to traditional lead-acid batteries. In addition, lead-carbon batteries exhibit significant advantages under 10-hour long-term energy storage conditions, with energy density reaching 40-60 Wh / kg, power density increased to 300-400 W / kg (approximately 50% of lithium iron phosphate batteries), and charge acceptance capacity increased by 8 times.

[0003] However, the introduction of carbon materials has also brought new problems. On the one hand, while high specific surface area carbon materials such as activated carbon can provide electric double-layer capacitor energy storage and improve the fast charge and discharge performance of the negative electrode, their overpotential for hydrogen is low. Adding carbon to the lead negative electrode will exacerbate the hydrogen evolution side reaction. Excessive hydrogen evolution not only increases the risk of battery water loss and thermal runaway, but may also prematurely deplete the electrolyte, causing the negative electrode plate to dry out and fail, thus negating the positive effect of carbon additives in extending battery life. To solve this problem, in recent years, research on lead-carbon battery negative electrode additives has shifted from single carbon materials to composite additives, that is, further introducing hydrogen evolution inhibitors or other functional components into carbon materials to simultaneously solve the problems of negative electrode sulfation and hydrogen evolution through synergistic effects. For example, researchers have tried various pathways such as carbon / conductive polymer composites, carbon / metal oxide composites, and carbon / nano-metal composites, in order to reduce the rate of carbon-induced hydrogen evolution and improve the interfacial compatibility between lead and additives while extending battery life. Existing literature reports the addition of a small amount of Bi to the negative electrode of lead-carbon batteries. 3+ In 3+ Metal compounds or organic inhibitors can increase the hydrogen evolution overpotential of lead / carbon composite electrodes by approximately 0.1–0.2 V, significantly reducing the hydrogen evolution current. Institutions such as the Dalian Institute of Chemical Physics, Chinese Academy of Sciences, have developed composite anode materials by coating lead powder with carbon and incorporating metals such as bismuth, cerium, and indium. These studies have demonstrated that the carbon layer can mitigate sulfation, and metal doping can suppress hydrogen evolution, thereby significantly improving the battery's charge-discharge coulombic efficiency and cycle stability. Furthermore, conductive polymers (such as polyaniline and polypyrrole) combined with carbon have also been used as anode additives to leverage their high overpotential and buffering effects. While these methods have delayed the degradation of lead-carbon batteries to some extent, there is still room for improvement. How to maintain the high double-layer capacitance advantage of carbon materials while further endowing the anode with Faraday pseudocapacitance and catalytic suppression of hydrogen evolution by introducing nanoscale functional components has become a key technical challenge for achieving long lifespan and high-rate performance in lead-acid batteries. This invention addresses this problem by proposing a hierarchical porous carbon anode material with synergistic activity of nano-metals, aiming to simultaneously improve the sulfation and hydrogen evolution problems of lead-acid battery anodes, and significantly improve the cycle life and charge-discharge performance of the battery. Summary of the Invention

[0004] This invention addresses the problems of sulfation failure and hydrogen evolution side reactions initiated by carbon additives in existing lead-acid battery anodes during partial state of charge (PSoC) cycling. It provides a hierarchical porous carbon anode material with synergistic activity of nano-metals and its applications. By optimizing the pore structure of the carbon matrix and introducing nano-metals or their compounds, this material achieves multiple functions, including suppressing sulfation, enhancing capacitance, and inhibiting hydrogen evolution reactions, thereby significantly improving the cycle life and charge / discharge performance of lead-acid batteries.

[0005] The hierarchical porous carbon anode material with synergistic activity of nano-metals provided by this invention includes the following technical solutions:

[0006] The hierarchical porous carbon matrix is ​​a multi-level porous carbon material comprising micropores (pore size <2 nm), mesopores (pore size range 2–50 nm), and macropores (pore size >50 nm). The micropores provide high specific surface area and electrical double-layer capacitance, primarily used for adsorbing ions from the electrolyte; the mesopores and macropores serve as ion transport channels and electrolyte storage spaces, accelerating electrochemical reaction kinetics and mitigating stress caused by volume changes in discharge products. Furthermore, the specific surface area of ​​the porous carbon ranges from 100 to 1200 m². 2 / g, pore volume range is 0.05–1.0cm³ 3 / g. Preferably, the optimized hierarchical porous carbon material has a specific surface area exceeding 1000 m². 2 / g, total pore volume is approximately 0.5–0.8 cm³. 3 / g, and the sum of the volumes of mesopores and macropores accounts for 50%–90% of the total pore volume, to ensure a balance between high ion diffusion rate and high capacitance characteristics.

[0007] Furthermore, nanoscale metal or compound particles are uniformly dispersed within the aforementioned hierarchical porous carbon matrix, forming a carbon-metal synergistic structure. The nanoscale metal particles are selected from transition metal elements (such as Fe, Co, Mn, etc.) or other metal elements (such as Sn, In, Bi, Pb, Ce, La, etc.), with a particle size ranging from 1 to 50 nm, preferably 2 to 20 nm, to fully utilize the nanoscale effect. Specifically, the metal particles are loaded onto the inner walls or surface of the carbon pores in the form of elemental, alloy, oxide, or hydroxide, and their mass content in the composite material ranges from 0.1% to 30%, preferably 1% to 10%. This range of metal content effectively enhances the electrochemical activity of the composite material without significantly affecting the conductivity of the carbon matrix.

[0008] Specifically, the nano-metal particles are loaded onto a porous carbon matrix via in-situ carbothermal reduction or impregnation pyrolysis, as follows: S1, dispersing hierarchical porous carbon material in a solution containing a metal precursor, wherein the metal precursor is a soluble metal salt or an organometallic complex, selected from one or more of nitrates, acetates, chlorides, and organometallic complexes; S2, ultrasonically dispersing and drying the mixed solution to obtain a carbon precursor coated with a metal salt; S3, subjecting the precursor to high-temperature treatment in an inert or reducing atmosphere to decompose the metal salt and generate nano-metal particles in situ. Preferably, the heat treatment temperature range is 300–800℃, and the time is 0.5–5 h to ensure highly dispersed metal particles with controllable size.

[0009] Furthermore, the carbon matrix is ​​also doped with heteroatoms selected from one or more of N, B, P, and S, which are introduced into the carbon framework in a bonded manner. Preferably, the nitrogen content in the carbon matrix is ​​0.5%–5 wt%, achieved by adding nitrogen-containing precursors such as urea, ammonia, or melamine during the carbonization process. Nitrogen doping not only improves the hydrophilicity and surface charge distribution uniformity of the carbon material, but also provides more coordination sites for subsequent loading of metal particles, thereby enhancing the bonding strength of the carbon-metal interface.

[0010] The material of this invention achieves a synergistic effect of inhibiting sulfation, enhancing capacitance, and inhibiting hydrogen evolution reaction through the following mechanism:

[0011] (a) Inhibition of sulfation: During discharge, porous carbon provides numerous adhesion / reaction interfaces for PbSO4 nuclei, preventing excessive grain growth and promoting the reduction of PbSO4 to Pb through its own conductive network, thus improving the utilization rate of the active material. Simultaneously, nano-metal particles (such as Pb and Sn) act as "nucleation seeds" uniformly distributed on the negative electrode, inducing Pb to deposit in the carbon pores as finer dendrites during charge and discharge, thereby alleviating the accumulation of sulfate on the surface. Experiments show that after adding the material of this invention, the specific surface area of ​​the negative electrode active material after discharge remains at 6–7 m². 2 / g or more, far exceeding 0.5m without added carbon. 2 / g, the formation of large PbSO4 crystals was significantly suppressed.

[0012] (b) Enhanced capacitance effect: Hierarchical porous carbon provides an electrically double-layer capacitor (EDLC) for energy storage, enabling rapid adsorption / desorption of H₂. + HSO4 - Ions act as buffers for transient high currents. Doped nanometals and their oxides provide Faraday pseudocapacitance or reversible redox reaction sites. For example, MnO x CoO x Transition metal oxides can undergo quasi-capacitive chemical reactions in sulfuric acid media, contributing additional capacity; n-type semiconductor oxides such as In₂O₃ improve the specific capacitance and charge transfer capability of the composite electrode. Experimental results show that the carbon composite material doped with In₂O₃ nanoparticles has an electrochemical capacitance that is about 30% higher than that of pure carbon material, which is reflected in the increased capacitive current in the cyclic voltammetry curve.

[0013] (c) Suppression of Hydrogen Evolution Reaction: The material of this invention significantly increases the hydrogen evolution overpotential of the negative electrode through multiple pathways, thus mitigating the side reaction of water decomposition. On one hand, nano-metals (such as Bi, In, Sn) form high-overpotential depolarizers in sulfuric acid solution, and their coating on the lead surface can increase the hydrogen evolution potential. On the other hand, metal oxide / hydroxide particles (such as In(OH)3, Bi2O3) preferentially reduce / evolve hydrogen during charging, acting as a sacrificial anode and buffer, preventing the large current from directly affecting water decomposition. In addition, functional groups such as pyridine nitrogen and graphitic nitrogen on the nitrogen-doped carbon surface can adsorb hydrogen intermediates (H·) generated at the cathode, reducing the rate of hydrogen atom recombination into H2. Under the combined effect, the hydrogen evolution current at the negative electrode decreases significantly. Experiments show that after adding the composite additive of this invention, the hydrogen evolution current density at the negative electrode is reduced by about 50% compared with that without the additive, and the hydrogen evolution overpotential is increased by about 80 mV.

[0014] The graded porous carbon anode material provided by this invention exhibits the following technical effects in practical applications: First, the cycle life is significantly extended. Under partial charge cycling conditions, the lead-carbon battery with the material of this invention retains 96.5% of its capacity after completing 6 sets (900 cycles) of the IEC61427 standard cycle test, which is 3 times that of the control battery without carbon (300 cycle life). In the 100% depth discharge cycle (DOD=100%) test, the control battery's capacity decayed to 80% after 81 cycles, while the battery with the material of this invention still retained 96.5% of its capacity after 350 cycles.

[0015] Secondly, high-rate performance and charge acceptance are significantly improved. Due to the dual energy storage mechanism of double-layer capacitor and Faraday pseudocapacitor, the composite negative electrode of this invention can rapidly respond to high-current charge and discharge, exhibiting excellent high-rate characteristics. For example, a lead-carbon battery incorporating the material of this invention can release 55% of its rated capacity at a 2C discharge rate, while a conventional battery only releases about 40%. The cold-start current at -20°C is more than twice that of a conventional battery. Charge acceptance tests show that when charged at a constant voltage limit of 2.40V, the battery of this invention can output nearly twice the current of the control battery in the early stages of charging, and the total charging time is shortened by about 15%.

[0016] Furthermore, the hydrogen evolution and water loss rates are significantly reduced. With the material of this invention, the hydrogen evolution reaction at the negative electrode is significantly suppressed. In the linear sweep voltammetry (LSV) test of the three-electrode system, the hydrogen evolution onset potential of the negative electrode with indium-doped carbon material shifts positively by approximately 50–100 mV compared to the undoped version, and the hydrogen evolution current density is significantly reduced. Long-term float charge (13.8V, 40℃, 4 weeks) tests show that the water loss rate of the control battery is approximately 4% per week, while that of the battery of this invention is only about 2.5%, with a lower and more stable float charge current. This demonstrates that the nano-metal-doped carbon additive effectively suppresses the hydrogen evolution side reaction at the negative electrode, thereby reducing water loss and delaying the risk of electrode drying and thermal runaway.

[0017] The graded porous carbon anode material of this invention is abundant and inexpensive, and can be prepared from agricultural and forestry waste or industrial by-products, making the process green and sustainable. When incorporated as an additive into lead-acid battery anode paste, it has no adverse effects on existing lead-acid battery manufacturing processes, requires no changes to the battery structure, and exhibits good compatibility. The material's effects are significant and economically feasible when added in the range of 1%–10%, making it easy to promote and implement in lead-acid battery production. Attached Figure Description

[0018] Figure 1 This is a schematic cross-sectional view of a novel lead-carbon battery structure.

[0019] Figure 2 This is a schematic diagram of the pore structure of the hierarchical porous carbon material of the present invention;

[0020] Figure 3 This is a schematic diagram showing the distribution of nano-metal dopants in porous carbon materials.

[0021] Figure 4 This is a comparison chart showing the improvement in battery performance brought about by the material of this invention. Detailed Implementation

[0022] This invention provides a hierarchical porous carbon anode material with synergistic activity of nano-metals and its application in long-life lead-carbon batteries. The following is in conjunction with the appendix... Figures 1 to 4 The technical solution of the present invention will be described in detail below with specific embodiments. In this embodiment, the specific implementation process of the present invention will be comprehensively described from the aspects of material preparation, structural characteristics, electrochemical performance testing and practical application scenarios.

[0023] The core of this invention lies in the synergistic effect of a hierarchical porous carbon matrix and nano-metal particles. This composite material, by optimizing the pore structure of the carbon matrix and introducing functionalized metal components, significantly improves the cycle life and charge-discharge performance of the lead-acid battery anode. Figure 2As shown, the hierarchical porous carbon matrix simultaneously contains micropores (<2 nm), mesopores (2–50 nm), and macropores (>50 nm), forming a unique hierarchical pore structure. This structure not only provides a high specific surface area to enhance the electric double-layer capacitance effect, but also provides rapid channels for ion transport through mesopores and macropores, thereby effectively alleviating the problem of lead sulfate crystal accumulation during discharge. Specifically, the micropores adsorb H+ from the electrolyte during discharge. + and HSO4 - The mesopores and macropores act as ion diffusion pathways and storage spaces, significantly improving the electrochemical reaction kinetics. Experimental data show that the optimized hierarchical porous carbon material can achieve a specific surface area of ​​1111.3 m². 2 / g, total pore volume is approximately 0.5–0.8 cm³. 3 / g, and the sum of the volumes of mesopores and macropores accounts for 50%–90% of the total pore volume, ensuring a balance between high ion diffusion rate and high capacitance characteristics.

[0024] Furthermore, such as Figure 3 As shown, nano-metal particles are uniformly dispersed in the pores of a porous carbon matrix, forming a tightly bonded carbon-metal interface. These nano-metal particles are selected from transition metals such as Fe, Co, Sn, Mn, and In, or their oxides or hydroxides, with a particle size range of 1–50 nm, preferably 2–20 nm, to fully utilize the nanosize effect. Specifically, the mass content of metal particles in the composite material ranges from 0.1% to 30%, preferably 1% to 10%. This range of metal content can enhance the electrochemical activity of the composite material without significantly affecting the conductivity of the carbon matrix. For example, Sn nanoparticles can be loaded onto a carbon matrix via an in-situ carbothermal reduction method, the specific process of which is as follows: S1, dispersing hierarchical porous carbon material in a solution containing SnCl2·2H2O; S2, drying after ultrasonic dispersion to obtain a metal salt-coated carbon precursor; S3, subjecting the precursor to high-temperature treatment in an inert or reducing atmosphere to decompose the metal salt and generate nano-metal particles in situ. Preferably, the heat treatment temperature range is 300–800℃, and the time is 0.5–5h to ensure that the metal particles are highly dispersed and their size is controllable. Experimental results show that the average particle size of Sn nanoparticles is about 10nm, and they are uniformly distributed in the carbon channels, exhibiting a point-like distribution with high electron density.

[0025] Furthermore, this invention further optimizes the surface properties of the carbon matrix through nitrogen doping. For example... Figure 3As shown, nitrogen is bonded to the carbon framework in the form of pyridine nitrogen and graphitic nitrogen, with a content ranging from 0.5% to 5 wt%. Nitrogen doping is achieved by adding nitrogen-containing precursors such as urea, ammonia, or melamine during the carbonization process, which significantly improves the hydrophilicity and surface charge distribution uniformity of the carbon material, while providing more coordination sites for subsequent metal particle loading. For example, in the preparation of rice husk-based porous carbon, urea was added as a nitrogen source, and the nitrogen content in the final carbon matrix was approximately 1 wt%. Experimental results show that nitrogen doping not only enhances the bonding strength of the carbon-metal interface but also significantly improves the overall performance of the composite material.

[0026] The material of this invention achieves a synergistic effect of inhibiting sulfation, enhancing capacitance, and inhibiting hydrogen evolution reaction through multiple mechanisms. First, as... Figure 4 As shown, the hierarchical porous carbon matrix provides numerous adhesion / reaction interfaces for PbSO4 nuclei during discharge, preventing excessive grain growth and promoting the reduction of PbSO4 to Pb through its own conductive network, thereby improving the utilization rate of the active material. Experimental data show that after adding the material of this invention, the specific surface area of ​​the negative electrode active material after discharge remains at 6–7 m². 2 / g or more, far exceeding 0.5m without added carbon. 2 / g, the formation of large PbSO4 crystals is significantly suppressed. Secondly, hierarchical porous carbon provides an electrical double-layer capacitor for energy storage, enabling rapid adsorption / desorption of H₂. + and HSO4 - Ions act as buffers for transient high currents. Doped nanometals and their oxides provide Faraday pseudocapacitance or reversible redox reaction sites. For example, MnO x and CoO xTransition metal oxides can undergo quasi-capacitive chemical reactions in sulfuric acid, contributing additional capacity; n-type semiconductor oxides such as In₂O₃ improve the specific capacitance and charge transfer capability of the composite electrode. Experimental results show that the electrochemical capacitance of the carbon composite material doped with In₂O₃ nanoparticles is increased by about 30% compared with that of pure carbon material, reflected in the increased capacitive current in the cyclic voltammetry curve. Finally, the material of this invention significantly improves the hydrogen evolution overpotential of the negative electrode through multiple pathways, mitigating the side reaction of water decomposition. On the one hand, nano-metals (such as Bi, In, Sn) form high overpotential depolarizers in sulfuric acid solution, and covering the lead surface can increase the hydrogen evolution potential; on the other hand, metal oxide / hydroxide particles (such as In(OH)₃, Bi₂O₃) preferentially reduce / evolve hydrogen during charging, acting as a sacrificial anode and buffer, avoiding the direct action of large current on water decomposition. In addition, functional groups such as pyridine nitrogen and graphitic nitrogen on the nitrogen-doped carbon surface can adsorb hydrogen intermediates generated at the cathode, reducing the rate of hydrogen atom recombination into H₂. Under the combined effect, the hydrogen evolution current of the negative electrode is significantly reduced. Experiments show that after adding the composite additive of the present invention, the hydrogen evolution current density at the negative electrode is reduced by about 50% compared with that without the additive, and the hydrogen evolution overpotential is increased by about 80mV.

[0027] In practical applications, the hierarchical porous carbon anode material of this invention exhibits significant technical advantages. For example... Figure 4 As shown, the capacity decay curve of a conventional lead-acid battery indicates that the control battery's capacity drops to 80% after less than 100 cycles; the capacity decay curve of a lead-carbon battery with added ordinary porous carbon shows that the cycle life is extended, but the capacity drops to 80% after about 150 cycles; while the capacity retention curve of a lead-carbon battery with the nano-metal-doped porous carbon material of this invention shows that the capacity is still above 90% after 350 cycles. This result verifies the effect of the material of this invention in significantly extending battery life. Furthermore, under the IEC61427 standard cycle test, the lead-carbon battery with the material of this invention still maintained a capacity retention rate of 96.5% after 6 sets (900 cycles), which is 3 times that of the control battery without added carbon (300 cycle life). In the 100% deep discharge cycle (DOD=100%) test, the control battery's capacity decayed to 80% after 81 cycles, while the battery with the material of this invention still maintained 96.5% capacity after 350 cycles.

[0028] The material of this invention also significantly improves the high-rate performance and charge acceptance of the battery. Due to its dual energy storage mechanism of electric double-layer capacitance and Faraday pseudocapacitance, the composite negative electrode can rapidly respond to high-current charge and discharge, exhibiting excellent high-rate characteristics. For example, a lead-carbon battery with the material of this invention can release 55% of its rated capacity at a 2C discharge rate, while a conventional battery releases only about 40%. The cold-start current at -20°C is more than twice that of a conventional battery. Charge acceptance tests show that when charged at a constant voltage limit of 2.40V, the battery of this invention can output nearly twice the current of the control battery in the early stages of charging, and the total charging time is shortened by about 15%. AC impedance analysis shows that the charge transfer resistance of the negative electrode of the battery with the material of this invention decreases by 35%, the Warburg diffusion impedance is significantly reduced, and the electric double-layer capacitance is significantly increased, indicating that the composite additive effectively improves the negative electrode reaction kinetics and capacitive behavior.

[0029] Furthermore, the material of this invention significantly reduces the rates of hydrogen evolution and water loss. Linear sweep voltammetry using a three-electrode system showed that the hydrogen evolution initiation potential of the negative electrode with indium-doped carbon material shifted positively by approximately 50–100 mV compared to the electrode without the material, and the hydrogen evolution current density was significantly reduced. Long-term float charge tests showed that the water loss rate of the control battery was approximately 4% per week, while that of the battery of this invention was only about 2.5%, with a lower and more stable float charge current. This demonstrates that the nano-metal-doped carbon additive effectively suppresses the hydrogen evolution side reaction at the negative electrode, thereby reducing water loss and delaying the risk of electrode drying and thermal runaway.

[0030] This invention utilizes a graded porous carbon anode material that is abundant and inexpensive, and can be prepared from agricultural and forestry waste or industrial byproducts, making the process green and sustainable. For example, porous carbon matrices can be produced from biomass raw materials such as rice husks, coconut shells, straw, and sawdust through carbonization and activation. When incorporated as an additive into lead-acid battery anode paste, it has no adverse effects on existing lead-acid battery manufacturing processes, requires no changes to the battery structure, and exhibits good compatibility. The material's effectiveness is significant and economically feasible when added at a concentration of 1%–10%, making it easy to implement in lead-acid battery production. In practical applications, the material formulation and dosage can be adjusted according to different needs to meet the performance requirements of start-stop batteries, energy storage power stations, and electric low-speed vehicle batteries.

[0031] In summary, the hierarchical porous carbon anode material with synergistic activity of nano-metals provided by this invention successfully solves the hydrogen evolution side effect caused by carbon additives in traditional lead-carbon batteries by optimizing the pore structure of the carbon matrix and introducing functionalized metal components. It significantly improves the cycle life and rate performance of lead-acid batteries, while maintaining the advantages of low manufacturing cost and safety and reliability. It has important practical value and good application prospects.

Claims

1. A hierarchical porous carbon anode material with synergistic activity of nano-metals, characterized in that... The invention comprises a hierarchical porous carbon matrix and nano-metal particles uniformly dispersed in the hierarchical porous carbon matrix. The hierarchical porous carbon matrix simultaneously contains micropores, mesopores, and macropores. The pore size of the micropores is less than 2 nm, the pore size of the mesopores ranges from 2 to 50 nm, and the pore size of the macropores is greater than 50 nm. The nano-metal particles are selected from transition metal elements or other metal elements in the form of elemental substances, alloys, oxides, or hydroxides.

2. The hierarchical porous carbon anode material as described in claim 1, characterized in that... The specific surface area of ​​the hierarchical porous carbon matrix ranges from 100 to 1200 m². 2 / g, pore volume range is 0.05–1.0cm³ 3 / g.

3. The hierarchical porous carbon anode material as described in claim 2, characterized in that... The specific surface area of ​​the hierarchical porous carbon matrix exceeds 1000 m². 2 / g, total pore volume is 0.5–0.8cm³ 3 / g, and the sum of the volumes of mesopores and macropores accounts for 50%–90% of the total pore volume.

4. The hierarchical porous carbon anode material as described in claim 1, characterized in that... The nano-metal particles have a particle size range of 1–50 nm and a mass content in the composite material range of 0.1%–30%.

5. The hierarchical porous carbon anode material as described in claim 4, characterized in that... The nano-metal particles have a particle size range of 2–20 nm and a mass content in the composite material range of 1%–10%.

6. The hierarchical porous carbon anode material as described in claim 1, characterized in that... The hierarchical porous carbon matrix is ​​doped with heteroatom elements, which are selected from one or more of nitrogen, boron, phosphorus, and sulfur.

7. The hierarchical porous carbon anode material as described in claim 6, characterized in that... The nitrogen content in the hierarchical porous carbon matrix ranges from 0.5% to 5 wt%, and is doped using urea, ammonia, or melamine.

8. The hierarchical porous carbon anode material as described in claim 1, characterized in that... The nano-metal particles are loaded onto a hierarchical porous carbon matrix by in-situ carbothermal reduction or impregnation pyrolysis, and the heat treatment temperature range is 300–800℃, and the time is 0.5–5h.

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