A core-shell structure type antimony oxide material, a preparation method and application thereof

Abstract

The application belongs to the technical field of lead-acid batteries, and particularly relates to a core-shell structure type antimony oxide material and a preparation method and application thereof. 13 The core-shell structure type antimony oxide material is composed of an Sb2O3 core and an Sb6O 13 The ratio of the peak intensity of the strongest characteristic diffraction peak of Sb2O3 to the peak intensity of the strongest characteristic diffraction peak of Sb6O 13 The core-shell structure type antimony oxide material can be used as a positive electrode additive of a lead-acid battery and is used in positive electrode lead paste of the lead-acid battery, so that the capacity and cycle life of the lead-acid battery are significantly improved.

Description

Technical Field

[0001] This invention relates to the field of lead-acid battery technology, specifically to a core-shell structured antimony oxide material, its preparation method, and its application. Background Technology

[0002] Lead-acid batteries have long dominated the global secondary battery market due to their high safety, low cost, and high recyclability. However, with the development of modern energy storage technologies, lead-acid batteries, with their low energy density and short cycle life, can no longer meet the demands of modern energy storage. Currently, the positive electrode plate is the key to improving the capacity and cycle life of lead-acid batteries.

[0003] In the context of maintenance-free lead-acid batteries using lead-calcium antimony-free alloy grids, a high-resistivity passivation layer forms at the interface between the positive electrode grid and the active material, leading to a sharp drop in early capacity (i.e., the "antimony-free effect," PCL-1), which limits the cycle life of lead-acid batteries. Therefore, it is necessary to introduce antimony to increase the interfacial carrier concentration and reduce the contact resistance.

[0004] To address the antimony-free effect, a primary method is to directly add exogenous free antimony compounds (such as Sb₂O₃) to the lead paste of lead-acid batteries' positive electrodes. Lead-acid battery positive electrode paste with added Sb₂O₃ is primarily composed of tribasic lead sulfate (3BS), which, after formation, yields fine-particle, low-porosity PbO₂ active material (PAM). The actual utilization rate of this PAM is extremely low, resulting in poor battery capacity. Furthermore, due to the lack of a large-size crystal "skeleton" for support, the bonding strength between PAM particles is weak. During repeated charge-discharge cycles, this structure is prone to fatigue and cracking due to volume changes, leading to softening and shedding (PCL-2), thus accelerating battery failure.

[0005] For PCL-2, an effective measure is to induce the formation of a large amount of tetrabasic lead sulfate (4BS) lead paste through the paste mixing and high-temperature, high-humidity curing stages. 4BS crystals are large and have high mechanical strength. After formation, they form a three-dimensional interlocked α-PbO2 framework structure, significantly improving the resistance of active materials to shedding. However, adding Sb2O3 to existing lead-acid battery cathode lead paste systems inhibits the formation of 4BS. This creates a technical challenge: "Adding antimony results in no 4BS framework, while maintaining 4BS results in insufficient antimony doping," hindering the simultaneous improvement of energy density and cycle life in lead-acid batteries.

[0006] The prior art CN107331862B discloses a method for preparing lead paste for deep-cycle batteries that facilitates the generation of 4BS. It adopts a method of adding acid twice and adding antimony trioxide additive in the later stage to form lead paste containing 4BS. Although it avoids the impact of the "antimony-free effect" on early capacity loss, the operation is complicated and the proportion of 4BS in the lead paste components is less than 18%, so the advantages of 4BS are not fully utilized.

[0007] To address the aforementioned technical challenges, developing a novel antimony-based cathode additive material compatible with 4BS growth is a key research focus and a pressing technological need in the current lead-acid battery field. Summary of the Invention

[0008] Based on this, the purpose of this invention is to provide a core-shell structured antimony oxide material, its preparation method, and its application. The core-shell structured antimony oxide material can be used as a positive electrode additive in lead-acid battery lead paste. It is compatible with 4BS growth during the preparation and curing processes of lead-acid battery lead paste, and avoids the "antimony-free effect" during the formation and charge / discharge processes of lead-acid batteries, significantly improving the capacity and cycle life of lead-acid batteries.

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] A core-shell structured antimony oxide material (Sb2O3@Sb6O) 13 ), consisting of the Sb2O3 kernel and Sb6O 13 The core-shell structure is composed of a dense outer shell and a dense inner shell. In the X-ray diffraction pattern of the core-shell antimony oxide material, the diffraction peak at 2θ = 27.7° corresponds to the strongest characteristic diffraction peak of Sb₂O₃, and the diffraction peak at 2θ = 30.0° corresponds to Sb₆O₃. 13 The strongest characteristic diffraction peak of Sb2O3 is similar in intensity to that of Sb6O. 13 The ratio of the peak intensities of the strongest characteristic diffraction peaks is (4~15):1; the Sb2O3 mass content in the core-shell structured antimony oxide material is 80~95wt%, with the balance being Sb6O. 13 .

[0011] The core-shell structured antimony oxide material of this invention has Sb₂O₃ as the core and Sb₆O₃ as the shell. 13 This is a material with a special morphological structure and a densely encapsulated outer shell. The core-shell structured antimony oxide material can be used as a positive electrode additive in lead-acid battery lead paste, because the Sb6O in the core-shell structured antimony oxide material... 13 The dense outer shell exhibits good stability. In the weakly alkaline environment of the lead-acid battery positive electrode paste during its preparation and curing process, it prevents the release of the Sb₂O₃ core, avoiding interference from free antimony ions. This promotes the formation of a large number of 4BS crystals in the lead-acid battery positive electrode paste, which is beneficial for increasing the porosity of PAM and enhancing the strength of the PAM framework structure. When the lead-acid battery made from this positive electrode paste undergoes formation and charge / discharge processes, due to the strong acidic electrolyte and potential-driven conditions, Sb₆O₃… 13The dense outer shell begins to disintegrate and simultaneously releases antimony ions from the core Sb2O3, thus preventing the "antimony-free effect" from affecting the lead-acid battery under deep charge-discharge cycles, significantly improving the capacity and cycle life of the lead-acid battery.

[0012] Furthermore, the Sb6O 13 The dense outer shell is generated by in-situ topological phase transition on the Sb₂O₃ surface induced by using thermosetting resin as a sacrificial template. This method utilizes thermosetting resin as a sacrificial template to induce an in-situ topological phase transition on the Sb₂O₃ surface, generating a stable antimony oxide, Sb₆O. 13 Protective layer (i.e., Sb6O) 13 (Densely coated outer shell), thus forming a core of Sb2O3 and a core of Sb6O3. 13 A core-shell structured composite material with a densely coated outer shell (Sb2O3@Sb6O) 13 ).

[0013] The core-shell structured antimony oxide material of the present invention is prepared by the following steps: Step S1: Disperse the thermosetting resin and Sb2O3 powder in water to form a uniform suspension in which the resin adsorbs Sb2O3; wherein the mass ratio of the thermosetting resin to the Sb2O3 powder is (0.17~4):1, and the total mass of the thermosetting resin and Sb2O3 powder in the suspension accounts for 5~50 wt% of the total mass of the suspension. Step S2: The suspension is dried by spray drying and granulated to obtain resin-coated Sb2O3 powder. Step S3: The resin-coated Sb2O3 powder is heated at 120~300℃ for 1~5 hours to cure and shape it; Step S4: Under an oxygen or air atmosphere, the resin-coated Sb2O3 powder cured and shaped in step S3 is heated to 350-550℃ at a heating rate of 2-20℃ / min and calcined for 0.1-5 hours to finally obtain the core-shell structured antimony oxide material (Sb2O3@Sb6O3). 13 ).

[0014] The method for preparing core-shell structured antimony oxide materials of the present invention uses thermosetting resin as a sacrificial template to induce an in-situ topological phase transition on the surface of Sb2O3 to generate Sb6O. 13 Even if some of the Sb2O3 on the surface of the Sb2O3 powder is transformed into Sb6O 13 The preparation yielded a core of Sb2O3 and an Sb6O3 core. 13The core-shell structured antimony oxide material is described. The process involves: step S1, where thermosetting resin is uniformly adsorbed onto the surface of Sb₂O₃ powder; step S2, where the Sb₂O₃ powder is completely coated with resin, forming a granular structure in which the Sb₂O₃ powder is uniformly dispersed within the resin coating layer; step S3, where the resin coating layer and the Sb₂O₃ structure are stabilized, and the density of the resin coating layer is increased; and step S4, where the cured and shaped resin-coated Sb₂O₃ powder is calcined at high temperature in oxygen / air, using the thermosetting resin as a sacrificial template to induce an in-situ topological phase transition on the Sb₂O₃ surface, generating a stable antimony oxide Sb₆O. 13 A densely coated outer shell was used to prepare a core of Sb₂O₃ and a core of Sb₆O₃. 13 The core-shell structured antimony oxide material having a densely encapsulated outer shell.

[0015] The method for preparing the core-shell structured antimony oxide material of the present invention involves sacrificing the thermosetting resin template. The resin-coated Sb₂O₃ powder, after being fixed and molded, is then subjected to high-temperature oxygen / air calcination to induce an in-situ topological phase transition on the Sb₂O₃ surface, generating a stable antimony oxide Sb₆O. 13 The dense outer shell mechanism lies in the fact that during the calcination process, the resin coating layer in the resin-coated Sb₂O₃ powder undergoes oxidative decomposition, releasing a large amount of heat that diffuses to the Sb₂O₃ surface. Therefore, under the thermally assisted catalytic oxidation, the Sb₂O₃ in the resin-coated Sb₂O₃ powder undergoes a chemical reaction on its surface and is transformed in situ into Sb₆O₃. 13 A dense outer shell is formed, thus creating a core-shell structured antimony oxide material (Sb2O3@Sb6O). 13 ).

[0016] The Sb6O in the core-shell structured antimony oxide material prepared by this invention 13The degree and density of the dense coating are strictly related to the process conditions of steps S1 to S4. For example, in step S1, if the mass ratio of thermosetting resin to Sb2O3 powder is too high, that is, if the thermosetting resin content is too high, it will increase the thickness of the resin coating layer, ultimately leading to excessive Sb2O3 conversion. The effective Sb2O3 content in the core-shell structured antimony oxide material will be too low, failing to eliminate the "antimony-free effect," thus affecting the cycle performance of the lead-acid battery. If the mass ratio of thermosetting resin to Sb2O3 powder is too low, that is, if the thermosetting resin content is too low, it will not be enough to completely coat the Sb2O3 powder. As a result, when the core-shell structured antimony oxide material is used as a positive electrode additive in the lead-acid battery positive electrode paste, it will release antimony ions during the paste mixing or curing stage and will not be able to form 4BS crystals. In step S1, if the solid content (i.e., the total content of thermosetting resin and Sb2O3 powder) in the suspension is too high, the suspension viscosity will be too high, which is not conducive to spray granulation and will prevent the formation of resin-coated Sb2O3 powder with small particle size and uniform size. In step S3, curing and shaping are carried out by heating at 120~300℃ for 1~5 hours to form a dense resin coating layer; if the temperature is too low or the heating time is too short, the thermosetting resin will not be sufficiently cured and shaped, and a dense resin coating layer will not be formed, which will ultimately cause Sb6O in the prepared core-shell structured antimony oxide material to be incomplete. 13 Cracks, gaps, or partial exposure between the outer shell and the Sb₂O₃ core ultimately expose the Sb₂O₃ core to the lead paste environment, failing to achieve the desired shielding effect against the release of antimony ions. In step S4, by controlling the heating rate, calcination temperature, and calcination time within the aforementioned ranges, a chemical reaction occurs on the Sb₂O₃ surface, causing it to transform in situ into Sb₆O₃. 13 The densely coated outer shell enables precise control of the shell composition. If the heating rate, calcination temperature and calcination time deviate from the above, it will affect the composition of the shell and the final effect of the core-shell structured antimony oxide material as a positive electrode additive in lead-acid batteries.

[0017] Preferably, in step S1, the molecular weight of the thermosetting resin is in the range of 5000~30000 Da, and the thermosetting resin is at least one selected from acrylic resin, phenolic resin, furfural resin, urea-formaldehyde resin, epoxy resin, and polyurethane resin. Using the thermosetting resin with a molecular weight of 5000~30000 Da listed above is beneficial for adsorption onto the Sb2O3 surface and the formation of a dense resin coating layer, which can act as a sacrificial template to induce in-situ topological phase transitions on the Sb2O3 surface to generate Sb6O. 13 Densely encapsulated shell.

[0018] More preferably, in step S1, the mass ratio of the thermosetting resin to the Sb2O3 powder is (0.2~3):1, and the total mass of the thermosetting resin and the Sb2O3 powder in the suspension accounts for 10~40wt% of the mass of the suspension; the thermosetting resin is at least one of acrylic resin, phenolic resin, urea-formaldehyde resin, and epoxy resin.

[0019] Preferably, in step S2, a spray dryer is used for spray drying, with the feed temperature set at 140~220℃, the outlet air temperature at 80~105℃, and the feed flow rate at 200~1000 mL / h. This spray drying method facilitates the coating of the thermosetting resin onto the Sb2O3 surface, forming a resin coating layer on the Sb2O3 surface.

[0020] Preferably, in step S2, the average particle size of the resin-coated Sb2O3 powder is 0.2~5 μm. Setting the average particle size of the resin-coated Sb2O3 powder obtained in S2 within the above range creates favorable conditions for the subsequent curing and shaping in step S3 and the calcination in step S4.

[0021] More preferably, in step S2, the feed temperature is 140~200℃, the heating time is 1~3h, and the average particle size of the resin-coated Sb2O3 powder is 0.5~5 μm.

[0022] More preferably, in step S3, heating is performed at 140~200°C for 1~3 hours. Curing and shaping under the above-mentioned curing temperature and heating time conditions is beneficial for forming a dense resin coating layer.

[0023] More preferably, in step S4, the temperature is increased to 360-500°C at a heating rate of 2-10°C / min, and calcined for 0.1-2 hours. Calcination under the above-mentioned heating rate, calcination temperature, and calcination time conditions is beneficial for the chemical reaction on the Sb₂O₃ surface and its in-situ transformation into Sb₆O. 13 Densely encapsulated shell.

[0024] The present invention also provides a lead-acid battery cathode additive, comprising any of the core-shell structured antimony oxide materials described above.

[0025] The present invention also provides a lead paste for a positive electrode of a lead-acid battery, comprising lead powder and any of the core-shell structured antimony oxide materials described above; based on the lead powder mass of 100wt%, the amount of the core-shell structured antimony oxide material is 0.05~1wt%.

[0026] The beneficial effects of this invention are: (1) The core-shell structured antimony oxide material of the present invention is used as a positive electrode additive for lead-acid batteries to prepare lead-acid battery positive electrode paste. Due to the stronger chemical stability of antimony oxide Sb6O13 The dense outer shell acts as a barrier, preventing the release of free antimony ions from the Sb₂O₃ core and thus avoiding their poisoning effect on the curing process. This promotes the formation of a large number of coarse and well-developed 4BS crystals in the lead-acid battery cathode paste. This not only increases the porosity of PAM but also significantly enhances the strength of the PAM framework structure, thereby improving the utilization rate of active materials and the discharge capacity of the lead-acid battery.

[0027] (2) Under the specific environment (strong acid, potential-driven) of lead-acid battery charging and discharging, the core-shell structured antimony oxide material of the present invention, Sb6O 13 The densely packed antimony oxide coating on the outer shell and Sb₂O₃ core can release antimony ions sequentially and continuously, effectively doping the positive electrode with antimony. This greatly improves the conductivity of the grid corrosion layer and the positive electrode active material, prevents the active material from softening and falling off, and significantly extends the lifespan of lead-acid batteries under deep charge-discharge conditions.

[0028] (3) Compared with other coating materials, the core-shell structured antimony oxide material of the present invention does not introduce other non-antimony source substances. On the one hand, it does not significantly reduce the antimony content of the material, and on the other hand, it greatly increases the effective antimony ion (Sb) content in the material. 3+ / Sb 5+ On the one hand, it improves the utilization rate of antimony; on the other hand, it avoids the negative effects of other non-antimony source materials on lead-acid batteries, such as reducing the conductivity of the plates and increasing the risk of battery water loss.

[0029] (4) The core-shell structured antimony oxide material of the present invention is prepared by using thermosetting resin as a sacrificial template and combining spray granulation and in-situ topological phase transition technology. The process route is scientifically and rationally designed. This preparation method not only achieves precise control of the shell composition, but also has strong parameter controllability and uniform powder morphology, making it very suitable for large-scale industrial production.

[0030] In summary, the core-shell structured antimony oxide material (Sb2O3@Sb6O) of the present invention... 13 As a positive electrode additive for lead-acid batteries, it can be used in lead-acid battery positive electrode paste to effectively improve the discharge performance of lead-acid batteries and extend the service life of batteries. It is especially suitable for the field of positive electrode additive technology for lead-acid energy storage batteries. Attached Figure Description

[0031] Figure 1 This is a SEM image of the epoxy resin-coated Sb2O3 powder from Example 1. Figure 2 The core-shell structured antimony oxide material Sb2O3@Sb6O in Example 1 13 SEM image; Figure 3 The core-shell structured antimony oxide material Sb2O3@Sb6O in Example 113 XRD pattern; Figure 4 The image shows the XRD pattern of the lead paste for the positive electrode of the lead-acid battery after curing in Example 1. Figure 5 Here is a SEM image of the lead paste for the positive electrode of the lead-acid battery after curing, as shown in Example 1. Figure 6 The image shows the SEM image of the lead paste for the positive electrode of the lead-acid battery after curing, as shown in Comparative Example 1. Detailed Implementation

[0032] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0033] Example 1 This embodiment provides a core-shell structured antimony oxide material, which induces an in-situ topological phase transition on the surface of Sb₂O₃ using epoxy resin as a sacrificial template to generate a stable antimony oxide Sb₆O. 13 This forms a core of Sb2O3 and a core of Sb6O. 13 The core-shell structured material with a densely encapsulated outer shell is prepared using the following steps: Step S1: Disperse epoxy resin with a molecular weight of 12000 Da and Sb2O3 powder in water, and stir thoroughly to ensure uniform dispersion, so that the epoxy resin is uniformly adsorbed on the surface of the Sb2O3 powder, and avoids agglomeration between powder particles, forming a uniform suspension of resin adsorbing Sb2O3; wherein, the mass ratio of epoxy resin to Sb2O3 powder is 1:1, and the total mass of epoxy resin and Sb2O3 powder accounts for 30 wt% of the suspension mass; Step S2: The above suspension is fed into a spray dryer at a feed rate of 300 mL / h for drying, wherein the feed temperature is 140℃ and the outlet air temperature is 85℃; then it is granulated and shaped to obtain spherical particles of epoxy resin-coated Sb2O3 powder; wherein the average particle size of the epoxy resin-coated Sb2O3 powder is 5 μm. Step S3: The epoxy resin-coated Sb2O3 powder obtained in S2 is heated at 140°C for 3 hours to cure and shape it, so that the structure of epoxy resin-coated Sb2O3 remains stable and the density of the resin coating layer is increased. Step S4: Place the cured and shaped epoxy resin-coated Sb2O3 powder in a muffle furnace, introduce air, and heat to 420℃ at a heating rate of 5℃ / min, calcining for 1 hour to finally obtain the core-shell structured antimony oxide material Sb2O3@Sb6O. 13 .

[0034] Figure 1 The SEM image of the epoxy resin-coated Sb2O3 powder obtained in step S2 of this embodiment is shown. It can be seen that the suspension is shaped into concave spherical particles after spray drying, in which many Sb2O3 powders are completely wrapped by epoxy resin, forming a particle structure in which Sb2O3 powder is uniformly dispersed in the resin coating layer. Figure 2 This embodiment demonstrates the core-shell structured antimony oxide material Sb₂O₃@Sb₆O₃ prepared in this example. 13 The SEM image. Combined with Figure 1 and Figure 2 It can be seen that the resin coating completely decomposes after calcination, and an in-situ topological phase transformation occurs on the Sb2O3 surface to generate Sb6O. 13 A dense coating layer was obtained after the resin coating layer completely decomposed. Figure 2 The microsphere morphology is composed of numerous nanoparticles, among which the numerous nanoparticles are the core-shell structured antimony oxide material Sb2O3@Sb6O in this embodiment. 13 . Figure 3 This embodiment demonstrates the core-shell structured antimony oxide material Sb₂O₃@Sb₆O₃ prepared in this example. 13 The XRD pattern shows that the characteristic peak at 2θ = 27.7° is the strongest characteristic diffraction peak of Sb₂O₃, and the characteristic peak at 2θ = 30.0° is the characteristic peak of Sb₆O₃. 13 The strongest characteristic diffraction peak of Sb2O3 is similar in intensity to that of Sb6O. 13 The ratio of the peak intensity of the strongest characteristic diffraction peak is 12.5:1; the core-shell structured antimony oxide material Sb2O3@Sb6O 13 The content of Sb2O3 in the middle is 92 wt%, and the balance is Sb6O. 13 .

[0035] This embodiment also provides a lead-acid battery cathode additive, namely the core-shell structured antimony oxide material Sb2O3@Sb6O in this embodiment. 13 .

[0036] This embodiment also provides a lead paste for the positive electrode of a lead-acid battery, which uses the core-shell structured antimony oxide material Sb2O3@Sb6O prepared in this embodiment. 13 Lead-acid battery positive electrode paste was prepared by conventional paste-making methods and dosages using lead powder, 4BS seed crystals, short fibers, deionized water, and sulfuric acid solution. Specifically, in this embodiment, the lead-acid battery positive electrode paste, based on 100wt% lead powder, uses the core-shell structured antimony oxide material Sb2O3@Sb6O. 13The dosage is 0.1 wt%, the dosage of 4BS seed crystals is 1 wt%, the dosage of short fibers is 0.1 wt%, the dosage of deionized water is 12 wt%, and the density of the sulfuric acid solution is 1.40 g / cm³. 3 The dosage is 8 wt%. The preparation steps are as follows: lead powder, 4BS seed crystals, and the core-shell structured antimony oxide material Sb2O3@Sb6O are added. 13 Short fibers are added to the paste mixing machine, and lead paste for lead-acid batteries is prepared according to conventional processes.

[0037] This embodiment also provides a positive electrode plate, which is a wet electrode plate made by coating the above-mentioned lead-acid battery positive electrode paste onto a commercial positive electrode Pb-Ca alloy grid. Finally, the wet electrode plate is cured according to a conventional curing process to promote the growth of 4BS crystals and the formation of cross-linked structures between 4BS crystals, ultimately obtaining the positive electrode plate.

[0038] Figure 4 The XRD pattern of the cured lead-acid battery cathode paste of this embodiment is shown. It can be seen that there is a characteristic diffraction peak corresponding to 4BS crystal at 2θ=10.8°, while the characteristic diffraction peak of 3BS crystal (2θ=9.0°) is not significant. This indicates that the core-shell structured antimony oxide material Sb2O3@Sb6O prepared in this embodiment is effective. 13 The lead paste used to make the positive electrode of the lead-acid battery contains a large amount of 4BS crystals. Figure 5 The image shows a SEM image of the cured lead-acid battery positive electrode paste of this embodiment, which shows that there are a large number of prismatic 4BS crystals in the lead-acid battery positive electrode paste.

[0039] This embodiment also provides a lead-acid battery. The positive electrode plate prepared by the above method is laminated and then manufactured into a 2V 20Ah lead-acid battery according to conventional processes. Deep cycle life testing was performed on the lead-acid battery prepared in this embodiment. The test regime for charge-discharge cycles was as follows: constant voltage 2.4667V, current-limited 10A charging for 4.25 hours, and discharge at 10A to 1.75V. When the discharge time was less than 96 minutes, it was considered the condition for the battery life to end. The test results are shown in Table 1.

[0040] Example 2 This embodiment provides a core-shell structured antimony oxide material, which induces an in-situ topological phase transition on the surface of Sb₂O₃ using urea-formaldehyde resin as a sacrificial template to generate a stable antimony oxide Sb₆O. 13 This forms a core of Sb2O3 and a core of Sb6O. 13 The core-shell structured material with a densely encapsulated outer shell is prepared using the following steps: Step S1: Disperse urea-formaldehyde resin with a molecular weight of 8000 Da and Sb2O3 powder in water, and stir thoroughly to ensure uniform dispersion, so that the urea-formaldehyde resin is uniformly adsorbed on the surface of the Sb2O3 powder, and avoids agglomeration between powder particles, forming a uniform suspension of resin adsorbing Sb2O3; wherein, the mass ratio of urea-formaldehyde resin to Sb2O3 powder is 0.5:1, and the total mass of urea-formaldehyde resin and Sb2O3 powder accounts for 36 wt% of the suspension mass; Step S2: The above suspension is fed into a spray dryer at a feed rate of 240 mL / h for drying, wherein the feed temperature is 160℃ and the outlet air temperature is 90℃; then granulation and shaping are performed to obtain spherical urea-formaldehyde resin coated Sb2O3 powder; wherein the average particle size of the urea-formaldehyde resin coated Sb2O3 powder is 3.5 μm. Step S3: The urea-formaldehyde resin-coated Sb2O3 powder obtained in S2 is heated at 160°C for 1 hour to cure and shape it, so that the structure of urea-formaldehyde resin-coated Sb2O3 remains stable and the density of the resin coating layer is increased. Step S4: Place the cured and shaped urea-formaldehyde resin-coated Sb2O3 powder in a muffle furnace, introduce air, and heat to 480℃ at a heating rate of 2℃ / min, calcining for 0.5h to finally obtain the core-shell structured antimony oxide material Sb2O3@Sb6O 13 The peak intensity of the strongest characteristic diffraction peak of Sb2O3 is similar to that of Sb6O. 13 The ratio of the peak intensity of the strongest characteristic diffraction peak is 6.7:1; the core-shell structured antimony oxide material Sb2O3@Sb6O 13 The content of Sb2O3 in the middle is 86wt%, and the balance is Sb6O. 13 .

[0041] The core-shell structured antimony oxide material Sb2O3@Sb6O prepared in this embodiment... 13 As a positive electrode additive for lead-acid batteries, lead-acid battery positive electrode paste, positive electrode plate, and 2V20Ah lead-acid battery were prepared sequentially using the same method as in Example 1. The difference lies in that: in the lead-acid battery positive electrode paste formulation, the core-shell structured antimony oxide material Sb2O3@Sb6O3 was used in this example. 13 The dosage was 0.5 wt%, and all other parameters were the same as in Example 1. The lead-acid battery prepared in this example was subjected to deep cycle life testing using the same method as in Example 1, and the test results are shown in Table 1.

[0042] Example 3 This embodiment provides a core-shell structured antimony oxide material, which induces an in-situ topological phase transition on the surface of Sb₂O₃ using phenolic resin as a sacrificial template to generate a stable antimony oxide Sb₆O. 13 This forms a core of Sb2O3 and a core of Sb6O. 13The core-shell structured material with a densely encapsulated outer shell is prepared using the following steps: Step S1: Disperse phenolic resin with a molecular weight of 25000 Da and Sb2O3 powder in water, and stir thoroughly to ensure uniform dispersion. This allows the phenolic resin to be uniformly adsorbed onto the surface of the Sb2O3 powder, preventing agglomeration between powder particles and forming a uniform suspension of resin-adsorbed Sb2O3. The mass ratio of phenolic resin to Sb2O3 powder is 0.67:1, and the total mass of phenolic resin and Sb2O3 powder accounts for 25 wt% of the suspension mass. Step S2: The above suspension is fed into a spray dryer at a feed rate of 500 mL / h for drying, wherein the feed temperature is 160℃ and the outlet air temperature is 90℃; then granulation and shaping are performed to obtain spherical phenolic resin coated Sb2O3 powder; wherein the average particle size of the phenolic resin coated Sb2O3 powder is 4 μm. Step S3: The phenolic resin-coated Sb2O3 powder obtained in S2 is heated at 160°C for 2 hours to cure and shape it, so that the structure of the phenolic resin-coated Sb2O3 remains stable and the density of the resin coating layer is increased. Step S4: Place the cured and shaped phenolic resin-coated Sb2O3 powder in a rotary kiln, introduce air, and heat to 460℃ at a heating rate of 5℃ / min, calcining for 0.3h to finally obtain the core-shell structured antimony oxide material Sb2O3@Sb6O 13 The peak intensity of the strongest characteristic diffraction peak of Sb2O3 is similar to that of Sb6O. 13 The ratio of the peak intensity of the strongest characteristic diffraction peak is 4.6:1; the core-shell structured antimony oxide material Sb2O3@Sb6O 13 The content of Sb2O3 in the middle is 81 wt%, and the balance is Sb6O. 13 .

[0043] The core-shell structured antimony oxide material Sb2O3@Sb6O prepared in this embodiment... 13 As a positive electrode additive for lead-acid batteries, lead-acid battery positive electrode paste, positive electrode plate, and 2V20Ah lead-acid battery were prepared sequentially using the same method as in Example 1. The difference lies in that: in the lead-acid battery positive electrode paste formulation, the core-shell structured antimony oxide material Sb2O3@Sb6O3 was used in this example. 13 The dosage was 0.05 wt%, and all other parameters were the same as in Example 1. The lead-acid battery prepared in this example was subjected to deep cycle life testing using the same method as in Example 1, and the test results are shown in Table 1.

[0044] Example 4 This embodiment provides a core-shell structured antimony oxide material, which induces an in-situ topological phase transition on the surface of Sb₂O₃ using acrylic resin as a sacrificial template to generate a stable antimony oxide Sb₆O.13 This forms a core of Sb2O3 and a core of Sb6O. 13 The core-shell structured material with a densely encapsulated outer shell is prepared using the following steps: Step S1: Disperse acrylic resin with a molecular weight of 5000 Da and Sb2O3 powder in water, and stir thoroughly to ensure uniform dispersion. This allows the acrylic resin to be uniformly adsorbed onto the surface of the Sb2O3 particles, preventing agglomeration between powder particles and forming a uniform suspension of resin-adsorbed Sb2O3. The mass ratio of acrylic resin to Sb2O3 powder is 0.33:1, and the total mass of acrylic resin and Sb2O3 powder accounts for 20 wt% of the suspension mass. Step S2: The above suspension is fed into a spray dryer at a feed rate of 620 mL / h for drying, wherein the feed temperature is 150℃ and the outlet air temperature is 86℃; then granulation and shaping are performed to obtain spherical particles of acrylic resin-coated Sb2O3 powder; wherein the average particle size of the acrylic resin-coated Sb2O3 powder is 3 μm. Step S3: The Sb2O3 powder coated with acrylic resin obtained in S2 is heated at 180°C for 1.5 hours to cure and shape it, so that the structure of Sb2O3 coated with acrylic resin remains stable and the density of the resin coating layer is increased. Step S4: Place the cured and shaped acrylic resin-coated Sb2O3 powder in a rotary kiln, introduce air, and heat to 380℃ at a rate of 10℃ / min. Calcinate for 2 hours to finally obtain the core-shell structured antimony oxide material Sb2O3@Sb6O. 13 The peak intensity of the strongest characteristic diffraction peak of Sb2O3 is similar to that of Sb6O. 13 The ratio of the peak intensity of the strongest characteristic diffraction peak is 6.2:1; the core-shell structured antimony oxide material Sb2O3@Sb6O 13 The content of Sb2O3 in the medium is 85wt%, and the balance is Sb6O. 13 .

[0045] The core-shell structured antimony oxide material Sb2O3@Sb6O prepared in this embodiment... 13 As a positive electrode additive for lead-acid batteries, lead-acid battery positive electrode paste, positive electrode plate, and 2V20Ah lead-acid battery were prepared sequentially using the same method as in Example 1. The difference lies in that: in the lead-acid battery positive electrode paste formulation, the core-shell structured antimony oxide material Sb2O3@Sb6O3 was used in this example. 13 The dosage was 1 wt%, and all other parameters were the same as in Example 1. The lead-acid battery prepared in this example was subjected to deep cycle life testing using the same method as in Example 1, and the test results are shown in Table 1.

[0046] Comparative Example 1 In this comparative example, pure Sb₂O₃ was used as the positive electrode additive for lead-acid batteries instead of the core-shell structured antimony oxide material Sb₂O₃@Sb₆O₃ in Example 1. 13 Lead-acid battery positive electrode paste, positive electrode plate, and 2V20Ah lead-acid battery were prepared sequentially using the same method and dosage as in Example 1. The lead-acid battery prepared in this comparative example was subjected to deep cycle life testing using the same method as in Example 1. The test results are shown in Table 1.

[0047] Figure 6 The image shows a SEM image of the cured lead-acid battery positive electrode paste in this comparative example. The image shows that the lead-acid battery positive electrode paste contains a large number of fine 3BS crystal particles.

[0048] Comparative Example 2 This comparative example does not use the core-shell structured antimony oxide material Sb₂O₃@Sb₆O₃ from Example 1. 13 (That is, without using antimony-containing positive electrode additives), lead powder was directly mixed with 4BS seed crystals, short fibers, deionized oil, and sulfuric acid, and the same method and amounts as in Example 1 were used to prepare lead-acid battery positive electrode paste, positive electrode plate, and 2V20Ah lead-acid battery. The lead-acid battery prepared in this comparative example was subjected to deep cycle life testing using the same method as in Example 1, and the test results are shown in Table 1.

[0049] Table 1. Cycle life test results of lead-acid batteries

[0050] As can be seen from the battery test results above, the cycle life of the lead-acid batteries in Examples 1 to 4 of the present invention is significantly improved compared with Comparative Example 1 and Comparative Example 2. The above results fully demonstrate the significant beneficial effects of the core-shell structured antimony oxide material of the present invention in improving the utilization rate of lead paste for the positive electrode of lead-acid batteries, increasing the capacity of lead-acid batteries, and extending cycle life.

[0051] Comparative Example 1 used pure Sb₂O₃ instead of the core-shell structured antimony oxide material of the present invention to prepare lead-acid battery positive electrode paste. The initial capacity and cycle life of the resulting lead-acid battery were significantly lower than those of Examples 1-4 of the present invention. This is because using pure Sb₂O₃ as a positive electrode additive for lead-acid batteries inhibits the formation of 4BS crystals in the lead-acid battery positive electrode paste, which is dominated by 3BS crystals. In contrast, the core-shell structured antimony oxide material of the present invention promotes the formation of 4BS crystals, resulting in a higher discharge capacity for the lead-acid battery. This is mainly attributed to the framework structure formed by the prismatic 4BS crystals, which has richer porosity than the framework structure formed by 3BS crystals, thereby effectively improving the utilization rate of active materials, and thus increasing the capacity of the lead-acid battery and extending its cycle life.

[0052] Although Comparative Example 2 can prepare positive electrode paste with 4BS crystals, it does not use the core-shell structured antimony oxide material of the present invention as a positive electrode additive for lead-acid batteries, nor does it use other antimony-containing positive electrode additives. As a result, the cycle life of the final lead-acid battery is significantly reduced.

[0053] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and the present invention also intends to include these modifications and variations.

Claims

1. A core-shell structured antimony oxide material, characterized in that, Composed of Sb2O3 kernel and Sb6O 13 The core-shell structure is composed of a dense outer shell and a dense inner shell. In the X-ray diffraction pattern of the core-shell antimony oxide material, the diffraction peak at 2θ = 27.7° corresponds to the strongest characteristic diffraction peak of Sb₂O₃, and the diffraction peak at 2θ = 30.0° corresponds to Sb₆O₃. 13 The strongest characteristic diffraction peak of Sb2O3 is similar in intensity to that of Sb6O. 13 The ratio of the peak intensities of the strongest characteristic diffraction peaks is (4~15):1; the Sb2O3 mass content in the core-shell structured antimony oxide material is 80~95wt%, with the balance being Sb6O. 13 .

2. The core-shell structured antimony oxide material according to claim 1, characterized in that, The Sb6O 13 The dense coating shell is generated by in-situ topological phase transition on the Sb2O3 surface induced by thermosetting resin as a sacrificial template.

3. The core-shell structured antimony oxide material according to claim 2, characterized in that, It is prepared by the following steps: Step S1: Disperse the thermosetting resin and Sb2O3 powder in water to form a uniform suspension in which the resin adsorbs Sb2O3; wherein the mass ratio of the thermosetting resin to the Sb2O3 powder is (0.17~4):1, and the total mass of the thermosetting resin and Sb2O3 powder in the suspension accounts for 5~50 wt% of the total mass of the suspension. Step S2: The suspension is dried by spray drying and granulated to obtain resin-coated Sb2O3 powder. Step S3: The resin-coated Sb2O3 powder is heated at 120~300℃ for 1~5 hours to cure and shape it; Step S4: Under an oxygen or air atmosphere, the resin-coated Sb2O3 powder cured and shaped in step S3 is heated to 350~550℃ at a heating rate of 2~20℃ / min and calcined for 0.1~5h to finally obtain the core-shell structured antimony oxide material.

4. The core-shell structured antimony oxide material according to claim 3, characterized in that, In step S1, the molecular weight of the thermosetting resin is 5000~30000 Da; the thermosetting resin is at least one of acrylic resin, phenolic resin, furfural resin, urea-formaldehyde resin, epoxy resin, and polyurethane resin.

5. The core-shell structured antimony oxide material according to claim 4, characterized in that, In step S1, the mass ratio of the thermosetting resin to the Sb2O3 powder is (0.2~3):1, and the total mass of the thermosetting resin and the Sb2O3 powder in the suspension accounts for 10~40wt% of the mass of the suspension; the thermosetting resin is at least one of acrylic resin, phenolic resin, urea-formaldehyde resin, and epoxy resin.

6. The core-shell structured antimony oxide material according to claim 3, characterized in that, In step S2, a spray dryer is used for spray drying, with the feed temperature set at 140~220℃, the outlet air temperature at 80~105℃, and the feed flow rate at 200~1000 mL / h; the average particle size of the resin-coated Sb2O3 powder is 0.2~5 μm.

7. The core-shell structured antimony oxide material according to claim 3, characterized in that, In step S3, heat at 140~200℃ for 1~3 hours.

8. The core-shell structured antimony oxide material according to claim 3, characterized in that, In step S4, the temperature is increased to 360-500℃ at a heating rate of 2-10℃ / min, and calcined for 0.1-2 hours.

9. A lead-acid battery positive electrode additive, characterized in that, Includes the core-shell structured antimony oxide material as described in any one of claims 1 to 8.

10. A lead paste for the positive electrode of a lead-acid battery, characterized in that, It includes lead powder and the core-shell structured antimony oxide material according to any one of claims 1 to 8; the amount of the core-shell structured antimony oxide material is 0.05 to 1 wt% based on 100 wt% of lead powder.

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