A method for preparing a positive electrode of a zinc-silver battery of the capacity type

Abstract

The application discloses a preparation method of a positive electrode of a capacity type zinc-silver storage battery, and relates to the technical field of storage battery preparation. 3 The positive electrode plate prepared by the method has excellent electrical performance and structural stability, and the capacity of the zinc-silver storage battery is effectively improved. The process steps are simple, and the parameters are controllable, so that the method is suitable for large-scale industrial production. Compared with the prior art, the utilization rate of active substances and the structural strength of the electrode plate are both significantly improved.

Description

Technical Field

[0001] This invention relates to the field of zinc-silver battery electrode preparation technology, specifically a method for preparing the positive electrode of a capacity-type zinc-silver battery. It is particularly suitable for zinc-silver battery applications requiring high capacity utilization and electrode structure stability, such as aerospace power reserves and long-endurance UAV power supplies. Background Technology

[0002] Zinc-silver batteries are widely used in aerospace, portable electronic devices, and other fields due to their high specific energy, stable discharge voltage, and good safety. The positive electrode plate, as the core component of the battery, has its manufacturing process directly affecting the battery's capacity, voltage plateau, and cycle life.

[0003] The existing cathode fabrication technologies mainly suffer from the following problems: For example, patent CN114335411A discloses a method for preparing a positive electrode plate to improve the voltage of a zinc-silver battery, which involves pressing at 7.5–8.5 MPa and sintering at a high temperature of 490–510°C, and requires the addition of a binder. While this method can improve the high-rate discharge voltage to some extent, it has the following significant drawbacks: (1) The electrode plate is only 0.05-0.2 mm thick, with low structural strength and is fragile; and the electrode plate prepared by this method has a low capacity and is only suitable for small capacity single cells. (2) High-temperature sintering causes active materials to clump together, reducing capacity utilization; (3) The use of binder increases the complexity and cost of the process; and the use of additives will significantly increase the internal resistance of the battery, making it unsuitable for the preparation of capacity-type cells; (4) The key structural parameters such as electrode size ratio and silver powder apparent density have not been systematically optimized, making it unsuitable for application scenarios with high capacity requirements.

[0004] Other existing technologies either rely on additives (such as carbon nanotubes) or only optimize local parameters, lacking comprehensive and coordinated control over the entire process of electrode size, silver powder apparent density, pressing, sintering, and cooling, resulting in: (1) The utilization rate of active substances is low (generally below 75%). (2) Insufficient strength of the electrode structure makes it easy for active materials to fall off, further reducing the battery capacity; (3) The process is complex and not suitable for large-scale production.

[0005] Therefore, there is an urgent need to develop a method for preparing the positive electrode of zinc-silver batteries that requires no binder, has a simple process, high structural strength, and high capacity utilization. Summary of the Invention

[0006] The present invention aims to solve the problems of low capacity utilization, poor plate structure strength and complex process in the existing zinc-silver battery cathode preparation methods, and to provide a cathode preparation method suitable for capacity-type batteries.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A method for preparing the positive electrode of a capacity-type zinc-silver battery, comprising: 1) Electrode design: Control the electrode aspect ratio to be 2.0–2.5:1, thickness to be 0.65–0.75 mm, and silver powder apparent density to be 3.8–4.2 g / cm³. 3 ; 2) Press molding: The silver powder is directly spread into the die of the size in step 1), the pressure is 6-8 MPa, the pressure is held for 3-5 seconds, and no adhesive is added; 3) Sintering: The formed electrode plates are sintered at 380-420℃ for 12-15 minutes; 4) Natural cooling: The sintered electrode sheet is naturally cooled to the ambient temperature to obtain the finished positive electrode plate.

[0008] Compared to higher design parameters, the size and apparent density matching of this design significantly ensure the structural stability of the electrode, effectively reduce active material shedding, and improve the utilization rate of the electrode's active material. Compared to lower design parameters, this matching relationship enables a more uniform distribution of active material, avoiding localized accumulation. The electrode design of this invention not only ensures structural stability but also achieves a more uniform distribution of active material, greatly improving the utilization rate of the electrode's active material and meeting the performance requirements of capacity-type zinc-silver batteries.

[0009] By precisely controlling the pressing pressure and holding time, the problem of excessively low porosity and decreased electrode reactivity caused by high-pressure pressing is avoided, while the problem of insufficient pressing pressure and failure of the electrode to be formed is also avoided.

[0010] Compared to the existing process of high-temperature sintering at 450℃, the sintering temperature range of the present invention can, on the one hand, avoid the problem of reduced electrode porosity and decreased utilization of active material caused by excessive plate formation during the sintering process; on the other hand, it can avoid the problem of reduced electrode conductivity caused by ineffective plate formation due to excessively low sintering temperature.

[0011] A slow and stable cooling process can prevent cracks in the electrode plates caused by thermal stress. Compared with water cooling or air cooling processes, natural cooling can reduce the internal stress of the electrode plates and significantly improve the yield of finished positive electrode plates.

[0012] Preferably, the aspect ratio of the electrode in step 1) is 2.2:1, the thickness is 0.75 mm, and the apparent density of the electrode is 3.8 g / cm³. 3 ; Preferably, the pressing pressure in step 2) is 6 MPa, and the holding time is 3 seconds; Preferably, the sintering temperature in step 3) is 400°C and the holding time is 12 min.

[0013] Preferably, the ambient temperature for the natural cooling process in step 4) is 20–25°C.

[0014] The beneficial effects of this invention are: Significantly improved capacity utilization: In Example 1, the battery capacity utilization rate reached 81%, which is far superior to the 75% in the conventional method.

[0015] Excellent structural stability: By optimizing the size ratio and apparent density matching, combined with low-temperature sintering and controlled natural cooling, the risk of active material shedding and thermal stress cracking is significantly reduced.

[0016] Simplified process and low cost: No adhesives or additives are required, the steps are simple, and it is suitable for large-scale industrial production.

[0017] Breakthrough in Conventional Technology: Existing technologies (such as CN114335411A) require high-temperature sintering (>490℃) combined with the use of a binder to achieve good performance, and the electrode thickness is only 0.05mm to 0.2mm, making it suitable only for small-capacity single-cell batteries. Furthermore, it requires coating preparation, resulting in complex processes and high costs. This invention achieves higher capacity utilization through low-temperature sintering, no binder, and combined with synergistic optimization of size / apparent density. Simultaneously, it is applicable to the preparation of large-capacity single cells. This achievement represents a significant breakthrough from conventional technologies. Attached Figure Description

[0018] Figure 1 The discharge curves are shown for the positive electrode materials of the embodiments and comparative examples of the present invention after being assembled into batteries. Detailed Implementation

[0019] The following detailed description illustrates the specific implementation method: Example 1 A method for preparing the positive electrode plate of a capacity-type zinc-silver battery includes the following steps: 1) Electrode design: The height-to-width ratio of the electrode is controlled at 2.2:1, the electrode thickness is 0.75mm, and the apparent density of the electrode is 3.8g / cm³. 3 ; 2) Pressing and molding: The silver powder is evenly spread in the die of the above-mentioned size, placed in the center of the press, and pressed with a pressure of 6MPa for 3s to obtain the molded electrode plate. 3) Electrode sintering: The formed electrode is placed in a sintering equipment, the sintering temperature is controlled at 400℃, and the holding time is 12min to obtain the sintered electrode sheet; 4) Cooling: The sintered electrode plate is naturally cooled to room temperature at an environment of 20-25℃ to obtain the finished positive electrode plate.

[0020] The above positive plate was assembled into a 6Ah zinc-silver battery, with an A / cm² voltage of 10mA / cm². 2 Discharge tests were conducted at a current density of 1.30V, with a cutoff voltage of 1.30V. The battery's capacity utilization rate was found to be 81%.

[0021] Example 2 A method for preparing the positive electrode plate of a capacity-type zinc-silver battery includes the following steps: 1) Electrode design: The height-to-width ratio of the electrode is controlled at 2.4:1, the electrode thickness is 0.75mm, and the apparent density of the electrode is 4.2g / cm³. 3 ; 2) Pressing and molding: The silver powder is evenly spread in the die of the above-mentioned size, placed in the center of the press, and pressed with a pressure of 6MPa for 3s to obtain the molded electrode plate. 3) Electrode sintering: The formed electrode is placed in a sintering equipment, the sintering temperature is controlled at 400℃, and the holding time is 12min to obtain the sintered electrode sheet; 4) Cooling: The sintered electrode plate is naturally cooled to room temperature at an environment of 20-25℃ to obtain the finished positive electrode plate.

[0022] Using the same test method as in Example 1, the capacity utilization rate of this battery was 74%.

[0023] Example 3 A method for preparing the positive electrode plate of a capacity-type zinc-silver battery includes the following steps: 1) Electrode design: The height-to-width ratio of the electrode is controlled at 2.2:1, the electrode thickness is 0.75mm, and the apparent density of the electrode is 3.8g / cm³. 3 ; 2) Pressing and molding: The silver powder is evenly spread in the die of the above-mentioned size, placed in the center of the press, and pressed with a pressure of 8MPa for 5s to obtain the molded electrode plate. 3) Electrode sintering: The formed electrode is placed in a sintering equipment, the sintering temperature is controlled at 420℃, and the holding time is 15min to obtain the sintered electrode sheet; 4) Cooling: The sintered electrode plate is naturally cooled to room temperature at an environment of 20-25℃ to obtain the finished positive electrode plate.

[0024] Using the same test method as in Example 1, the battery's capacity utilization rate was 77%.

[0025] Comparative Example 1 A method for preparing the positive electrode plate of a capacity-type zinc-silver battery includes the following steps: 1) Electrode design: The height-to-width ratio of the electrode is controlled at 2.6:1, the electrode thickness is 0.45mm, and the apparent density of the electrode is 4.1g / cm³. 3 ; 2) Pressing and molding: The silver powder is evenly spread in the die of the above-mentioned size, placed in the center of the press, and pressed with a pressure of 10MPa for 3 seconds to obtain the molded electrode plate. 3) Electrode sintering: The formed electrode is placed in a sintering equipment, the sintering temperature is controlled at 450℃, and the holding time is 10min to obtain the sintered electrode sheet; 4) Cooling: The sintered electrode plate is naturally cooled to room temperature at an environment of 20-25℃ to obtain the finished positive electrode plate.

[0026] Using the same test method as in Example 1, the capacity utilization rate of this battery was 70%.

[0027] Comparative Example 2 A method for preparing the positive electrode plate of a capacity-type zinc-silver battery includes the following steps: 1) Electrode design: The height-to-width ratio of the electrode is controlled at 1.6:1, the electrode thickness is 1.14mm, and the apparent density of the electrode is 3.9g / cm³. 3 ; 2) Pressing and molding: The silver powder is evenly spread in the die of the above-mentioned size, placed in the center of the press, and pressed with a pressure of 5MPa for 5s to obtain the molded electrode plate. 3) Electrode sintering: The formed electrode is placed in a sintering equipment, the sintering temperature is controlled at 450℃, and the holding time is 12min to obtain the sintered electrode sheet; 4) Cooling: The sintered electrode plate is naturally cooled to room temperature at an environment of 20-25℃ to obtain the finished positive electrode plate.

[0028] Using the same test method as in Example 1, the capacity utilization rate of this battery was 60%.

[0029] Comparative Example 3 A method for preparing the positive electrode plate of a capacity-type zinc-silver battery includes the following steps: 1) Electrode design: The height-to-width ratio of the electrode is controlled at 2.2:1, the electrode thickness is 0.75mm, and the apparent density of the electrode is 3.8g / cm³. 3 ; 2) Pressing and molding: The silver powder is evenly spread in the die of the above-mentioned size, placed in the center of the press, and pressed with a pressure of 6MPa for 3s to obtain the molded electrode plate. 3) Electrode sintering: The formed electrode is placed in a sintering equipment, the sintering temperature is controlled at 500℃, and the holding time is 12min to obtain the sintered electrode sheet; 4) Cooling: The sintered electrode plate is naturally cooled to room temperature at an environment of 20-25℃ to obtain the finished positive electrode plate.

[0030] Using the same testing method as in Example 1, the battery's capacity utilization rate was 65%. The excessively high temperature in this method led to excessive electrode condensation and reduced battery porosity, which is also one of the key factors contributing to the reduced utilization rate of active materials.

[0031] Effect Analysis: The test results from the examples and comparative examples show that: The electrode design parameters optimized by this invention are: size ratio 2.0–2.5:1, thickness 0.65–0.75 mm, and silver powder apparent density 3.8–4.2 g / cm³. 3 Combined with precisely controlled pressing (6-8 MPa, 3-5 s), sintering (380-420℃, 12-15 min) and natural cooling processes, the utilization rate of active materials in the positive electrode plate can be significantly improved, and the battery capacity utilization rate can reach up to 81%.

[0032] When the process parameters deviate from the protection scope of this invention, such as Figure 1 As shown, the battery capacity utilization rates of Comparative Examples 1, 2, and 3 are significantly reduced, at only 70%, 60%, and 65%, respectively.

[0033] The above examples, compared with comparative examples, show that when parameters such as electrode size ratio, thickness, apparent density, pressing pressure, and sintering temperature deviate from the scope of this invention, the capacity utilization rate decreases significantly (down to as low as 60%). This invention, through end-to-end synergistic optimization, achieves a capacity utilization rate of up to 81% without the need for binders or additives, surpassing existing technology reports and making it suitable for zinc-silver battery applications requiring high capacity and structural stability.

[0034] The above descriptions are merely embodiments of the present invention, and common knowledge such as specific technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A method for preparing the positive electrode of a capacity-type zinc-silver battery, characterized in that, Includes the following steps: 1) Electrode design: The height-to-width ratio of the electrode is controlled to be 2.0–2.5:1, the electrode thickness is 0.65 mm–0.75 mm, and the apparent density of the silver powder in the electrode is 3.8–4.2 g / cm³. 3 ; 2) Pressing and molding: The silver powder is directly spread in the die of the size in step 1), without adding any adhesive, and pressed with a pressure of 6-8 MPa for 3-5 seconds to obtain the molded electrode plate. 3) Electrode sintering: Place the formed electrode in a sintering equipment, control the sintering temperature at 380℃~420℃, and hold for 12~15 minutes; 4) Cooling treatment: The sintered electrode sheet is naturally cooled to the ambient temperature to obtain the finished positive electrode plate.

2. The positive electrode preparation method according to claim 1, characterized in that, The electrode described in step 1) has a height-to-width ratio of 2.2:1, a thickness of 0.75 mm, and an apparent density of 3.8 g / cm³. 3 .

3. The positive electrode preparation method according to claim 1, characterized in that, The pressing pressure in step 2) is 6 MPa, and the holding time is 3 seconds.

4. The positive electrode preparation method according to claim 1, characterized in that, The sintering temperature in step 3) is 400℃ and the holding time is 12min.

5. The positive electrode preparation method according to claim 1, characterized in that, The ambient temperature for the natural cooling process described in step 4) is 20–25°C.

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