High-activity silver oxide cathode material and preparation method and application thereof

Abstract

The invention discloses a high-activity silver oxide cathode material and a preparation method and application thereof, and belongs to the technical field of cathode materials. The preparation method of the high-activity silver oxide cathode material comprises the following steps: synthesizing a silver nanowire active substance with a high specific surface area by adopting a one-pot polyol method; pressing and sintering the silver nanowire active substance into a silver blank by adopting a vacuum hot pressing sintering technology; carrying out multi-stage constant-current charging formation on the silver blank in a hanging lug type single formation mode; and washing the formed electrode with absolute ethyl alcohol and deionized water for multiple times, drying to obtain a silver oxide electrode, and carrying out a discharge performance test. The obtained silver oxide electrode is large in specific surface area, high in porosity and easy to fully contact and react with electrolyte, the utilization rate of electrode active substances and the electrode discharge efficiency are improved, the battery activation time is shortened, and the silver oxide electrode is suitable for being applied to underwater high-power energy consumption equipment.

Description

Technical Field

[0001] This invention relates to the field of cathode material technology, and in particular to a highly active silver oxide cathode material, its preparation method, and its application. Background Technology

[0002] Seawater-activated batteries use an electrochemically active metal or alloy as the anode and a metal chloride, silver oxide, or air electrode as the cathode, utilizing seawater as the electrolyte to achieve underwater or special environmental operation. Seawater-activated batteries offer advantages such as long dry-state storage time, high safety, maintenance-free operation, short activation time, low-temperature resistance, and irreplaceable advantages for underwater propulsion. They can be widely used as underwater propulsion power sources for underwater unmanned vehicles, electric torpedoes, and other underwater and deep-sea equipment. Silver oxide electrode material is a key material and important component of seawater-activated batteries, and also one of the important factors affecting their performance. The theoretical specific energy of silver oxide (AgO) electrodes is 248 Wh / kg, and the resistivity is approximately 10⁻⁶. -1 Ω / m, possessing advantages such as high energy density, high specific power, and stable operating voltage, and the theoretical specific capacity of AgO (432mAh·g) -1 ) is close to Ag2O (230mAh·g -1 It is twice the size of the commonly used cathode material for seawater-activated batteries.

[0003] However, existing seawater-activated battery cathode materials have two main problems. First, the silver oxide cathode material is a disordered, densely packed grain with few pores between the grains. Second, during high-power discharge, the OH groups generated by the silver oxide cathode in the seawater-activated battery... - Ion diffusion is slow, OH - Ions accumulate inside the electrode, resulting in significant concentration polarization, a low electrode potential, and low utilization of the electrode active material, leading to a decline in the performance of the seawater-activated battery. Secondly, during the reaction, the silver oxide cathode material reacts layer by layer from the outside in, initially forming monovalent silver oxide (Ag₂O). Monovalent silver oxide is an insulator with a resistivity of 10⁻⁶. 6 Ω / m, later Ag is formed, resistivity is about 10 Ω / m. -8 During high-power discharge, the monovalent silver oxide insulating film attached to the surface of the silver oxide grains exhibits significant ohmic polarization, resulting in a severe lag in electrode potential and a slow activation response. Therefore, based on these shortcomings, there is an urgent need to propose a highly active silver oxide (AgO) cathode material to address the technical problems in the existing technology. Summary of the Invention

[0004] Based on the technical problems to be solved by the present invention, the present invention proposes a highly active silver oxide cathode material, its preparation method and application.

[0005] One objective of this invention is to provide a method for preparing a highly active silver oxide cathode material, comprising: S1, synthesizing a high specific surface area silver nanowire active material using a one-pot polyol method; S2, pressing and sintering the silver nanowire active material into a silver blank electrode using a vacuum hot-pressing sintering technique; S3, performing multi-stage constant current charging formation on the silver blank using a hook-type single-stage formation method; and S4, repeatedly washing and drying the charged and formed electrode with anhydrous ethanol and deionized water to obtain a highly active silver oxide cathode material.

[0006] Further, a one-pot polyol method was used to synthesize high specific surface area silver nanowire active material, including: S11, weighing silver nitrate and dissolving it in ethylene glycol solution to prepare silver nitrate ethylene glycol solution; weighing PVP and dissolving it in ethylene glycol solution to prepare PVP ethylene glycol solution; preparing FeCl3 ethylene glycol solution; S12, adding the ethylene glycol solution to a vacuum reactor, stirring and heating; slowly adding the PVP ethylene glycol solution dropwise to the reactor; adding the FeCl3 ethylene glycol solution control agent; adding the silver nitrate ethylene glycol solution, stirring continuously, and synthesizing silver nanowires; S13, post-processing the silver nanowires; after the reaction is complete, the reactor is naturally cooled to room temperature; removing the upper layer of the precipitate, washing the reaction product with deionized water and dispersing it; separating the precipitate from the liquid using a high-speed centrifuge; washing the precipitate with anhydrous ethanol and drying it to obtain post-processed silver nanowires; S14, testing the post-processed silver nanowires to obtain tested silver nanowires.

[0007] Further, vacuum hot pressing sintering technology is used to press and sinter the silver nanowire active material into a silver blank electrode, including: S21, assembling a graphite module in a steel frame, controlling the internal filling space to be consistent with the design size of the high-activity silver oxide electrode material; tightening external bolts to prevent the mold from falling apart during movement, and placing the lower pressing block in the filling space to obtain a silver blank sintering mold; S22, laying a silver mesh of the corresponding size flat in the filling space to obtain a current collector; weighing 24-44g of the silver nanowires and loading them into the silver blank sintering mold, vibrating the mold to make the silver nanowires evenly spread throughout the filling space; placing a high-purity graphite separator on top of the silver nanowires and pre-pressing to obtain a shaped blank; S23, repeating the process of placing a silver mesh in the filling space, weighing the silver nanowires and loading them into the silver blank sintering mold, and placing a high-purity graphite separator on top of the silver nanowires, so that... The silver blank sintering mold contains multiple shaped blanks; the upper pressure block is placed on the filled multiple shaped blanks to obtain the filled silver blank sintering mold; S24, the filled silver blank sintering mold is placed into the hot pressing equipment, and the position of the filled silver blank sintering mold is adjusted to ensure that the upper pressure column of the hot pressing equipment and the upper pressure block of the filled silver blank sintering mold are in a straight line to avoid the filled silver blank sintering mold from shifting and causing uneven force; the furnace door is closed, the vacuum pump of the hot pressing equipment is turned on, and the vacuum in the furnace is controlled at about 2-8 Pa; after the vacuum reaches the specified requirements, vacuum hot pressing sintering is performed, with the pressure set at 30-70 kN, the sintering temperature at 350-450℃, and the holding time at 10-20 min; after sintering is completed, after the hot pressing equipment cools naturally, the vacuum is removed, the sintered silver blank sintering mold is taken out, and after the mold cools, it is demolded to obtain the silver blank electrode.

[0008] Furthermore, the silver blank is subjected to multi-stage constant current charging formation through a single-stage formation process using a hanging-type electrode, including: S31, welding tabs onto the electrodes of the silver blank to obtain silver blank electrode tabs; connecting the silver blank electrode tabs to the electrodes of the formation equipment, which is a hanging-type single-stage formation equipment, placed in a formation fixture to form a suspended formation; the electrode plates in the formation tank are connected in parallel, connecting n formation cells, where n is a natural number; the two formation tanks are connected in series to ensure that multiple sets of electrodes can be formed at one time. S32. The assembled battery is then added to a 1.3 g / mol KOH electrolyte at a certain temperature. The assembled battery is allowed to stand in the electrolyte for 3-8 minutes until the electrolyte fully contacts and activates the silver electrode blank, resulting in an electrolyte-activated battery. S33. The electrolyte-activated battery is then subjected to multi-stage constant current charging formation using a formation regime. The formation temperature is 75-85°C, and the formation regime is a high current stage at 15-25 mA / cm². 2Charging was performed at high current density for 6–8 hours, reaching 20–40% charge and the AgO formation potential, with the cell voltage increasing from 1.2–1.5V to 1.8–2.0V; the low current stage was 8–12 mA / cm². 2 Charging was performed at high current density for 12–20 hours. When the total charge reached 120–140%, the positive electrode voltage reached a plateau. The increasing trend of the Ag electrode voltage was basically consistent with the cell voltage, with a final voltage of 2.0V–2.3V. During the stabilization phase, the current density was 2–4 mA / cm². 2 Current density during charging for 8–12 seconds: 1–3 mA / cm² 2 Discharge at a current density of 3–8 seconds and perform 800–1200 charge-discharge cycles to obtain a formed battery that has undergone multi-stage constant current charging.

[0009] Further, the electrode after charging and formation is repeatedly cleaned and dried with anhydrous ethanol and deionized water to obtain a highly active silver oxide cathode material, including: S41, removing the formed battery after multi-stage constant current charging, and repeatedly cleaning it with anhydrous ethanol and deionized water until there is no alkalinity on the electrode surface to obtain a dry electrode; S42, wiping the moisture off the surface of the dry electrode to obtain a cleaned electrode material; S43, placing the cleaned electrode material in a vacuum drying oven for drying at 80-100°C for 1.5-2.5 hours to obtain a dried highly active silver oxide electrode material.

[0010] Furthermore, the preparation method of the highly active silver oxide cathode material also includes cutting the dried highly active silver oxide electrode material, including: cutting 3-7 mm off each piece of the dried highly active silver oxide electrode material along its respective length direction to achieve the silver oxide cathode size designed for the seawater activated battery, thereby obtaining the highly active silver oxide electrode material to be tested.

[0011] Furthermore, the preparation method of the highly active silver oxide cathode material also includes testing the highly active silver oxide electrode material to be tested, including: testing the composition, specific surface area, loose density, appearance quality, size, electrical properties and other properties of the highly active silver oxide electrode material to be tested, to obtain the highly active silver oxide electrode material.

[0012] The second objective of this invention is to provide a highly active silver oxide cathode material, which is prepared according to the preparation method of a highly active silver oxide cathode material.

[0013] Furthermore, the highly active silver oxide cathode material and the aluminum alloy anode material are assembled into a battery, which achieves a current density of 600 mA / cm² under the conditions of 79℃~83℃, 4mol / L~4.5mol / L NaOH solution + 20g / L Na₂SnO₃ solution. 2At that time, the average battery voltage was 1.705V after 6.5 minutes, and the ratio of the actual discharge capacity to the theoretical discharge capacity of the silver oxide cathode was 78.7%; the current density was 200mA / cm². 2 At that time, the average battery voltage was 1.771V, and the ratio of the actual discharge capacity to the theoretical capacity of the silver oxide cathode material was 85.3%.

[0014] The third objective of this invention is to provide an application of a highly active silver oxide cathode material, namely, its application in battery manufacturing, medical equipment, and drinking water purification.

[0015] Furthermore, the highly active silver oxide cathode material can also be applied to other existing feasible devices and environments, including but not limited to chemical sensors, small devices, aerospace, etc.

[0016] Compared with the prior art, the present invention proposes a highly active silver oxide cathode material, its preparation method and application, which has the following beneficial effects:

[0017] The highly active silver oxide electrode proposed in this invention is prepared by an electrochemical formation method. The preparation process parameters are reasonably controlled, the production cost is low, the efficiency is high, and it is suitable for large-scale industrial production.

[0018] Furthermore, the active material of the highly active silver oxide electrode proposed in this invention is silver nanowires. The prepared silver nanowires have a one-dimensional linear structure, in which the electron transport path is smoother, thereby improving the overall conductivity of the material.

[0019] Furthermore, the hot pressing sintering method for highly active silver oxide electrodes proposed in this invention has significant advantages over single pressing or sintering methods in terms of improving electrode performance and optimizing the preparation process, and can better meet the requirements for high quality and high performance of silver electrodes. Attached Figure Description

[0020] Figure 1 A process flow diagram of a highly active silver oxide cathode material preparation method according to an embodiment of the present invention is shown;

[0021] Figure 2 A flowchart of a high specific surface area silver nanowire preparation process according to an embodiment of the present invention is shown;

[0022] Figure 3 An SEM image of a silver nanowire according to an embodiment of the present invention is shown;

[0023] Figure 4 A flow chart of a hot-pressing sintering process for a highly active cathode material according to an embodiment of the present invention is shown.

[0024] Figure 5 A flow chart of a high-activity cathode material formation process according to an embodiment of the present invention is shown;

[0025] Figure 6 A schematic diagram of a hanging-type formation battery assembly according to an embodiment of the present invention is shown;

[0026] Figure 7 This image shows a SEM image of a silver blank after electrodeposition according to an embodiment of the present invention.

[0027] Figure 8 A sample image of a highly active silver oxide electrode according to an embodiment of the present invention is shown;

[0028] Figure 9 An embodiment of the present invention illustrates a highly active silver oxide cathode material with a current density of 600 mA / cm². 2 Discharge voltage curve under the specified conditions;

[0029] Figure 10 An embodiment of the present invention illustrates a highly active silver oxide cathode material with a current density of 200 mA / cm². 2 Discharge voltage curve under the specified conditions;

[0030] The components include: 1. shunt; 2. DC power supply; 3. formation electrolyte; 4. formation tank; 5. silver oxide electrode; and 6. auxiliary electrode. Detailed Implementation

[0031] Exemplary embodiments of the present application will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present application are shown in the drawings, it should be understood that the present application may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this application will be thorough and complete, and will fully convey the scope of the present application to those skilled in the art.

[0032] Unless otherwise specified, the technical means used in the following embodiments are conventional means well known to those skilled in the art, and the reagents and materials in this invention are obtained from the market or other public channels.

[0033] The technical principles of the highly active silver oxide cathode material, its preparation method, and its application described in this invention mainly include:

[0034] By improving the morphology and size of the active material in silver oxide (AgO) electrode materials, the electrode formation efficiency can be increased, thereby improving the electrode utilization rate. By improving the forming and formation process of electrode materials, electrode materials with suitable electrode porosity and excellent microstructure can be prepared, providing more active sites for silver oxide electrode discharge while improving the electrode formation efficiency and utilization rate, so as to meet the performance requirements of high-power battery discharge and shorten the activation time when high-power battery applications are used.

[0035] This invention utilizes silver nanowires as the active material. The interwoven network structure of the silver nanowires has a large porosity, which facilitates electrolyte penetration, allowing for sufficient contact between the electrode and the electrolyte, thereby improving the efficiency of the electrode reaction. The good porosity and permeability further enhance the mechanical properties of the electrode, making it less susceptible to damage during preparation and use. It can withstand a certain degree of bending and stretching without affecting electrode performance, exhibiting excellent mechanical properties. The large aspect ratio of silver nanowires provides more active sites, which is beneficial for loading other active materials or catalysts, further improving electrode performance and demonstrating strong loading capacity.

[0036] This invention employs a silver blank hot pressing sintering forming technology. Hot pressing sintering combines pressure and sintering to complete one-step forming, which can effectively improve the electrode preparation efficiency. Moreover, the simultaneous action of pressure and sintering can effectively solve the problem of small-scale loss of active material, improve material utilization, and prevent active material from dissolving in alkaline electrolyte, thus affecting electrode performance.

[0037] This invention employs a loop-type monopolar sheet formation technology. The loop-type monopolar sheet formation method is simple to operate and reduces the complex assembly process compared to electrode assembly. Due to the larger formation tank, the electrodes are fixed within the formation frame, and the distance between the electrodes is larger, which effectively reduces the occurrence of short circuits and improves the formation quality. Furthermore, in the loop-type formation method, the electrodes are suspended individually, resulting in more uniform stress and less deformation, which helps to ensure the consistency and stability of the electrodes.

[0038] This invention employs a multi-stage charging formation method for silver electrodes, which improves production efficiency and reduces electrode damage compared to traditional high-current charging or pulse charging methods. In particular, the stabilization charge-discharge stage allows the silver electrode to achieve better performance balance under different charge-discharge states, enabling the electrode to operate more stably and reducing performance fluctuations during subsequent use. Compared to constant-current charging, variable-current charging facilitates the conversion of Ag to Ag₂O and AgO, resulting in a more complete electrode reaction and a more uniform material distribution within the electrode. This not only increases the electrode's discharge capacity but also improves discharge performance under high current densities.

[0039] Based on the above principles, please refer to Figure 1 This invention proposes a highly active silver oxide cathode material, its preparation method, and its application. This invention uses an electrochemical formation method to conduct modification experiments on highly active silver-based electrode materials. Through experiments on key preparation processes of high specific surface area silver nanowires and high-efficiency hot pressing sintering and formation processes, highly active cathode materials are prepared.

[0040] (1) Preparation of high specific surface area silver nanowires

[0041] Using silver nanowires as the active material alters the microstructure and size of the active material in silver electrodes. Silver nanowires possess unique nano-effects and excellent physicochemical properties such as low electrical resistance, high specific surface area, and high activity. Using silver nanowires as the active material in silver electrodes effectively increases the electrode's specific surface area. The network structure formed by the interwoven silver nanowires has a large porosity, which facilitates electrolyte penetration, allowing for sufficient contact between the electrode and the electrolyte, thereby improving the efficiency of the electrode reaction. The flexibility and ductility of silver nanowires contribute to improving the mechanical properties of the electrode, making it less prone to damage during preparation and use, and enabling it to withstand certain bending and stretching without affecting electrode performance.

[0042] (2) Silver electrodes were prepared by hot pressing sintering.

[0043] The morphology of an electrode determines its parameters, including specific surface area, porosity, open porosity, mechanical strength, and resistivity. Hot pressing sintering combines pressure and sintering, achieving one-step forming and effectively improving the efficiency of electrode fabrication. Furthermore, the simultaneous action of pressure and sintering effectively addresses the issue of minor active material loss, increasing material utilization. In addition, hot pressing sintering combines pressure and temperature, accelerating densification and structural optimization processes, and effectively shortening fabrication time.

[0044] (3) Silver oxide electrode polarization technology

[0045] Different charging methods, electrolytes, temperatures, and post-charging electrode treatments during the formation process result in variations in the content, distribution, and properties of substances within the silver electrode, significantly impacting its performance. The bipolar bipolar formation method, with its larger contact area and increased current-carrying area, promotes uniform current diffusion across the electrode reaction surface, thereby increasing the reaction rate. The hanging formation method for silver electrodes offers a larger formation tank space, smaller micro-short circuits, and a fixed electrode frame design that maintains the distance between plates, further contributing to uniformity in the formation results.

[0046] A staged constant current charging method is adopted for charging. First, the current density is charged at a high current density. When the potential reaches the oxygen evolution critical value, the current density is reduced by half. At this time, the current density decreases. After charging for a period of time, the potential reaches the oxygen evolution critical value again, and the current density is reduced by half again. The charging cutoff voltage is used for control. This method greatly improves the formation efficiency and avoids unnecessary energy consumption and electro-hydraulic loss.

[0047] The proposed methods for preparing highly active silver oxide electrode materials include:

[0048] S1. High specific surface area silver nanowire active material was synthesized by a one-pot polyol method.

[0049] S2. The silver nanowire active material is pressed and sintered into a silver blank using vacuum hot pressing sintering technology.

[0050] S3. The silver blank is formed by multi-stage constant current charging through a single-stage formation method using an ear-type method.

[0051] S4. After formation, the electrode is repeatedly washed with anhydrous ethanol and deionized water and dried to obtain a silver oxide electrode for discharge performance testing.

[0052] Furthermore, a one-pot polyol method was used to synthesize high specific surface area silver nanowire active materials, including:

[0053] S101. Weigh out silver nitrate and dissolve it in an appropriate amount of ethylene glycol solution to prepare a silver nitrate ethylene glycol solution with a concentration of 0.1–0.5 mol / L; weigh out a certain amount of PVP and dissolve it in ethylene glycol solution to prepare a PVP ethylene glycol solution with a concentration of 0.1–1.0 mol / L; prepare a 1 mM–10 mM FeCl3 ethylene glycol solution.

[0054] S102. Add the ethylene glycol solution to a vacuum reactor and heat it to 100-150°C under magnetic stirring. After the solution temperature stabilizes, slowly add the PVP ethylene glycol solution dropwise to the reactor at a rate of 1-5 mL / min. Add the FeCl3 ethylene glycol solution as a control agent. Add the silver nitrate ethylene glycol solution and continue stirring for 1-3 hours to synthesize silver nanowires.

[0055] S103. The silver nanowires are post-treated. After the reaction is completed, the reaction vessel is naturally cooled to room temperature. The upper layer of the precipitate is removed, and the reaction product is washed with deionized water and dispersed by ultrasonic vibration. The precipitate and liquid are separated by a high-speed centrifuge with the centrifugation rate controlled at 8000-12000 r / min. The precipitate is washed with anhydrous ethanol 3-5 times. The precipitate is placed in a vacuum drying oven at 55-65℃ and dried for 1 hour to obtain the post-treated silver nanowires.

[0056] S104. The post-processed silver nanowire precipitate is subjected to comprehensive testing, including observing the morphology and size of the nanowires with TEM and SEM, and analyzing the crystal structure with XRD to obtain the tested silver nanowires.

[0057] Furthermore, the silver nanowire active material is pressed and sintered into a silver blank using vacuum hot pressing sintering technology, including:

[0058] S201. Assemble a graphite module inside a steel frame, ensuring the internal filling space matches the design dimensions of the highly active silver oxide electrode material; tighten external bolts to prevent the mold from falling apart during movement, and place the lower pressure block inside the filling space to obtain a silver blank sintering mold.

[0059] S202. A silver mesh of the corresponding size is laid flat in the filling space to obtain a current collection material; 34g of the silver nanowires are weighed and loaded into the silver blank sintering mold, and the mold is vibrated to make the silver nanowires evenly spread throughout the filling space; a high-purity graphite spacer is placed on the silver nanowires and pre-pressed to obtain a shaped blank.

[0060] S203. Repeat the process of placing a silver mesh in the filling space, weighing the silver nanowires and loading them into the silver blank sintering mold, and placing a high-purity graphite spacer on the silver nanowires, so that the silver blank sintering mold contains multiple shaped blanks; place the upper pressure block on the filled multiple shaped blanks to obtain the filled silver blank sintering mold.

[0061] S204. Place the filled silver blank sintering mold into the hot press equipment, adjust the position of the filled silver blank sintering mold to ensure that the upper pressure column of the hot press equipment and the upper pressure block of the filled silver blank sintering mold are in a straight line to avoid uneven force caused by the displacement of the filled silver blank sintering mold; close the furnace door, turn on the vacuum pump of the hot press equipment, and control the vacuum in the furnace at about 5 Pa; after the vacuum reaches the specified requirements, perform vacuum hot pressing sintering, set the pressure to 50 kN, the sintering temperature to 400℃, and the holding time to 15 min; after sintering is completed, after the hot press equipment cools naturally, remove the vacuum, take out the sintered silver blank sintering mold, and demold after the mold cools to obtain the silver blank.

[0062] Furthermore, the silver blank is subjected to multi-stage constant current charging formation via ear-type single-stage formation, including:

[0063] S301. Connect the tabs of the formed battery to the electrodes of the formed equipment. The formed equipment is a hanging single formed equipment, which is placed in the formed fixture to form a suspended formed battery. The electrode plates in the formed tank are connected in parallel to connect n formed batteries, where n is a natural number. The two formed tanks are connected in series to ensure that multiple sets of electrodes can be formed at one time to obtain assembled formed batteries.

[0064] S302. The assembled battery is added to a 1.3 g / mol KOH electrolyte at a certain temperature. The assembled battery is then left to stand in the electrolyte for 5 minutes until the electrolyte and silver electrode blank are fully contacted and activated, thus obtaining an electrolyte-activated battery.

[0065] S303. The electrolyte-activated battery is subjected to multi-stage constant current charging formation using a formation regime; the formation temperature is 81.5℃±1.5℃; the formation regime is a high current stage at 20mA / cm 2Charging was performed at a high current density for 6–8 hours, until the charge reached 30%, achieving the AgO formation potential, and the cell voltage increased from 1.5V to 1.8V; the low current stage was performed at 10mA / cm². 2 Charging was performed at a specific current density for 16 hours. When the total charge reached 130%, the positive electrode voltage plateaued (1.83V–1.96V). The increasing trend of the Ag electrode voltage was basically consistent with the cell voltage, with a final voltage of 2.1V–2.2V. During the stabilization phase, the current density was 3mA / cm². 2 Current density during charging for 10 seconds: 1–3 mA / cm 2 Discharge at a current density of 5 seconds and perform 1000 charge-discharge cycles to obtain a formed battery that has undergone multi-stage constant current charging.

[0066] Furthermore, the electrode after charging and formation is repeatedly washed and dried with anhydrous ethanol and deionized water to obtain a highly active silver oxide cathode material, comprising:

[0067] S401. Remove the formation battery that has undergone multi-stage constant current charging. Based on its alkalinity, repeatedly clean it with anhydrous ethanol and deionized water until there is no alkalinity on the electrode surface to obtain a dry electrode.

[0068] S402. Wipe the moisture off the surface of the dry electrode to obtain the cleaned electrode material;

[0069] S403. The cleaned electrode material is placed in a vacuum drying oven for drying at 125°C for 2 hours to obtain a highly active silver oxide electrode material after drying.

[0070] Furthermore, each sheet of the dried high-activity silver oxide electrode material is cut by 5mm along its length to achieve the silver oxide cathode size designed for the seawater activated battery. The scraps are kept for performance testing to obtain the high-activity silver oxide electrode material to be tested.

[0071] Furthermore, the composition, specific surface area, loose density, appearance quality, size, electrical properties, and other properties of the high-activity silver oxide electrode material to be tested are detected to obtain the high-activity silver oxide electrode material.

[0072] Example 1

[0073] This invention proposes an experimental method for preparing high specific surface area silver nanowires.

[0074] Mainly includes:

[0075] (1) Experimental preparation: silver nitrate (analytical grade), polyvinylpyrrolidone (PVP, 58K), ethylene glycol (analytical grade), NaCl (analytical grade), KBr (analytical grade), FeCl3 (analytical grade), Cu2Cl (analytical grade), anhydrous ethanol, deionized water, vacuum reactor, magnetic stirrer, high-speed centrifuge, vacuum drying oven.

[0076] (2) Solution preparation: Weigh a certain amount of silver nitrate and dissolve it in an appropriate amount of ethylene glycol solution to prepare a silver nitrate ethylene glycol solution with a concentration of 0.1-0.5 mol / L; Weigh a certain amount of PVP and dissolve it in ethylene glycol solution to prepare a PVP ethylene glycol solution with a concentration of 0.1-1.0 mol / L; Prepare a 1 mM-10 mM FeCl3 ethylene glycol solution.

[0077] (3) Synthesis of silver nanowires: A certain amount of ethylene glycol solution was added to a vacuum reactor and heated to 100-150°C under magnetic stirring. After the solution temperature stabilized, the ethylene glycol solution of PVP was slowly added dropwise to the reactor at a rate of 1-5 mL / min. A certain amount of FeCl3 ethylene glycol solution was added as a control agent. A certain amount of silver nitrate ethylene glycol solution was added and stirred continuously for 1-3 h.

[0078] (4) Post-treatment: After the reaction is completed, the reaction vessel is naturally cooled to room temperature; the upper layer of the precipitate is removed, and the reaction product is washed with deionized water and dispersed by ultrasonic vibration; the precipitate and liquid are separated by high-speed centrifuge with the centrifugation rate controlled at 10000r / min; the precipitate is washed 3 times with anhydrous ethanol; the precipitate is placed in a vacuum drying oven at 60℃ and dried for 1h.

[0079] (5) Performance testing: The dried precipitate is comprehensively tested, including using TEM and SEM to observe the morphology and size of the nanowires, using XRD to analyze its crystal structure, and testing the purity and dispersibility of the precipitate.

[0080] result:

[0081] Please see Figure 2 and Figure 3 The prepared silver nanowires are long, uniform in size, and free from bending and aggregation. The nanostructure of the silver nanowires allows the active material to have a thin mass transfer layer and a high proportion of surface atoms. This is the main reason for the improved discharge performance of the silver oxide electrode.

[0082] Example 2

[0083] This invention proposes a vacuum hot-pressing sintering test for silver electrodes.

[0084] Mainly includes:

[0085] (1) Assemble the graphite module inside the steel frame, ensuring that the internal filling space matches the designed silver oxide dimensions. Tighten the external bolts to prevent the mold from falling apart during movement, and place the lower pressure block inside the filling space.

[0086] (2) Lay out a silver mesh of the corresponding size in the filling space as a flow collection material.

[0087] (3) Weigh 34g of silver nanowires and put them into the mold, and shake the mold to make the silver nanowires evenly spread throughout the filling space.

[0088] (4) Place the high-purity graphite separator on the silver nanowire and press it down.

[0089] (5) Repeat (2) to (4) to make multiple pieces of molded blanks in the mold.

[0090] (6) Place the upper pressure block on the filled silver nanowires.

[0091] (7) Place the filled silver nanowire mold into a specific area of ​​the equipment and adjust the mold position to ensure that the upper pressure column of the hot pressing equipment and the upper pressure block of the mold are on the same straight line to avoid uneven force due to mold displacement.

[0092] (8) Close the furnace door and turn on the equipment vacuum pump to control the vacuum inside the furnace at about 5Pa;

[0093] (9) After the vacuum reaches the specified requirements, vacuum hot pressing sintering begins. The pressure is set at 50 kN, the sintering temperature at 400 °C, and the holding time at 15 min.

[0094] (10) After sintering, wait for the equipment to cool naturally, then remove the vacuum and take out the mold. After the mold cools down, demold.

[0095] result:

[0096] Please see Figure 4 Vacuum hot-pressing sintering technology applies pressure and heat in a vacuum environment, resulting in tighter bonding between material particles and reduced porosity. Electrodes prepared by conventional pressing techniques often have more voids in their structure due to insufficient pressure or the morphology and size of the active material. While sintered electrodes are also sintered, the synergistic effect of vacuum and pressure is not as strong as that of vacuum hot-pressing sintering, resulting in a more compact structure for silver electrodes. Furthermore, the compact structure leads to better conductivity, lower resistance, and more efficient current conduction. The vacuum environment reduces oxidation and other reactions, keeping the electrode purer during preparation and improving chemical stability. The dense structure and excellent performance also make the electrode more stable over long-term use, less prone to performance degradation.

[0097] Example 3

[0098] This invention proposes a silver oxide electrodeation test.

[0099] Mainly includes:

[0100] (1) The formation device used is a hanging single formation: the tabs of the formed battery are connected to the electrodes of the formation equipment, and then placed in the formation fixture to form a hanging formation; the electrode plates in the tank are connected in parallel, which can connect multiple formed batteries. The two formation tanks are connected in series to ensure that multiple sets of electrodes can be formed at one time.

[0101] (2) After the formation battery is assembled, add 1.3 g / mol KOH formation electrolyte at a certain temperature, and let the formation battery stand in the electrolyte for 5 minutes until the electrolyte and silver electrode blank are fully contacted and activated.

[0102] (3) The formation process employs a two-stage constant current formation: the formation temperature is 81.5℃±1.5℃; the formation process is a high-current stage with a current of 20mA / cm. 2 Charging was performed at a high current density for 6–8 hours, until the charge reached 30%, achieving the AgO formation potential, and the cell voltage increased from 1.5V to 1.8V; the low current stage was performed at 10mA / cm². 2 Charging was performed at a specific current density for 16 hours. When the total charge reached 130%, the positive electrode voltage plateaued (1.83V–1.96V). The increasing trend of the Ag electrode voltage was basically consistent with the cell voltage, with a final voltage of 2.1V–2.2V. During the stabilization phase, the current density was 3mA / cm². 2 Current density during charging for 10 seconds: 1–3 mA / cm 2 Discharge at a current density of 5 seconds, and repeat this charge-discharge cycle 1000 times.

[0103] result:

[0104] Please see Figures 5-7 As the charging degree increases, the microstructure of the electrode changes, and silver oxide crystals gradually form on the surface of the silver nanowires, transforming the electrode from a loose and porous structure to a dense structure.

[0105] The formation process employs a hook-type monopolar electrode formation method. Through bipolar electrode formation, the contact area between the bipolar electrode and the electrode is increased, resulting in a larger overcurrent area, which facilitates uniform current diffusion on the electrode reaction surface and improves the reaction rate. The hanging-type formation method for silver electrodes offers a large formation tank space, smaller micro-short circuits, and the electrode fixing frame design, which fixes the distance between the electrodes, further promotes uniformity in the formation results.

[0106] A staged constant current charging method is adopted for charging. First, the current density is charged at a high current density. When the potential reaches the oxygen evolution critical value, the current density is reduced by half. At this time, the current density decreases. After charging for a period of time, the potential reaches the oxygen evolution critical value again, and the current density is reduced by half again. The charging cutoff voltage is used for control. This method greatly improves the formation efficiency and avoids unnecessary energy consumption and electro-hydraulic loss.

[0107] Example 4

[0108] This invention proposes a cleaning and drying test.

[0109] Mainly includes:

[0110] (1) The removed electrodes are alkaline, so they are repeatedly cleaned with deionized water until there is no alkalinity on the electrode surface.

[0111] (2) Wipe the surface of the electrode dry.

[0112] (3) Place the cleaned electrode material in a vacuum drying oven for drying at 125°C for 2 hours.

[0113] result:

[0114] The electrode material is formed using potassium hydroxide electrolyte, which has a certain alkalinity. During dry storage after assembly into a battery, the electrode material will absorb moisture from the air and self-discharge, thereby losing battery capacity and damaging the battery separator. Cleaning and drying can prevent this from happening.

[0115] Example 5

[0116] This invention proposes a cutting and performance testing method.

[0117] Mainly includes:

[0118] (1) After drying, each piece of high-activity silver oxide electrode material is cut off by 5mm along its length to achieve the silver oxide cathode size designed for seawater activated batteries. The scraps are kept for product inspection.

[0119] (2) Test the composition, specific surface area, loose density, appearance quality, size and electrical properties of the sample.

[0120] result:

[0121] Please see Figure 8 The dried high-activity silver oxide electrode material can be cut to size as needed, and the cut high-activity silver oxide electrode material still retains its original properties.

[0122] Example 6

[0123] This invention proposes a performance testing experiment for silver oxide cathode materials prepared by a specific process.

[0124] Mainly includes:

[0125] The silver oxide cathode material prepared using the process described in the previous section was assembled with an aluminum alloy anode to form an Al-AgO battery. The corresponding performance tests were conducted, and the results are as follows:

[0126] (1) Test process temperature: 81.5℃±1.5℃;

[0127] (2) Electrolyte conditions: 4.5 mol / L NaOH + 20 g / L Na2SnO3 solution;

[0128] (3) Constant current discharge current density: 600 mA / cm 2 200mA / cm 2 .

[0129] result:

[0130] Please see Figure 9 and Figure 10 The highly active silver oxide electrode material, under the conditions of 81.5±1.5℃ and (4~4.5mol / L NaOH+20g / L Na2SnO3) solution, achieved an efficiency of 600mA / cm. 2 Constant current discharge was performed, and the average electrode potential was maintained at 1.705V for 6.5 minutes. The ratio of the actual discharge capacity to the theoretical capacity of the silver oxide electrode was 78.7%. Under the conditions of 81℃±2℃, 4~4.5mol / L strongly alkaline electrolyte + 20g / L corrosion inhibitor solution, the current density was 200mA / cm. 2 At that time, the average voltage of the battery (anode material is "high potential aluminum alloy anode") was maintained at 1.771V within 15 minutes, and the ratio of the actual discharge capacity to the theoretical capacity of the silver oxide electrode material was 85.3%.

[0131] Comparative Example

[0132] Please refer to Table 1. This invention presents a comparative experiment of a highly active silver oxide cathode material with silver oxide (AgO) electrodes synthesized directly by chemical methods, silver oxide (AgO) electrodes synthesized in situ by chemical methods, silver oxide (AgO) electrodes obtained by electrochemical formation methods, and micron or nano silver powder as electrode active materials.

[0133] Table 1 Comparative experimental results of the highly active silver oxide cathode of the present invention

[0134]

[0135]

[0136] The comparison results show that the silver oxide electrode prepared by the present invention has a higher discharge voltage, providing a higher output voltage in high-power energy-consuming devices; furthermore, the silver oxide electrode prepared by the present invention has a shorter activation time, can enter the working state more quickly, reduces energy loss, and is suitable for fast-response scenarios; furthermore, shortening the time from electrode start-up to stable operation makes the device start-up faster and has better battery life or sensitivity performance.

[0137] In summary, the highly active silver oxide electrode proposed in this invention is prepared via an electrochemical formation method. This method offers reasonable control of process parameters, low production costs, and high efficiency, making it suitable for large-scale industrial production. The active material is silver nanowires, which possess a one-dimensional linear structure, allowing for smoother electron transport paths and improving the overall conductivity of the material. The hot-pressing sintering method for the highly active silver oxide electrode proposed in this invention offers significant advantages in improving electrode performance and optimizing the preparation process, better meeting the requirements for high-quality and high-performance silver electrodes. The high-activity silver oxide electrode formation method proposed in this invention adopts a loop-type single-electrode formation method, which is simple to operate and reduces the complex assembly process compared to electrode assembly. Due to the larger formation tank and the electrode being fixed within the formation frame, the distance between electrodes is larger, effectively reducing the occurrence of short circuits and improving formation quality. In addition, the electrode is suspended individually in the loop-type formation method, resulting in more uniform stress and less deformation, which helps to ensure the consistency and stability of the electrode. The electrode after hot-pressing sintering is formed by a high-current charging + low-current charging + stabilization charge-discharge cycle, which improves production efficiency and reduces electrode damage compared to traditional high-current charging or pulse charging methods. In particular, the stabilization charge-discharge stage allows the silver electrode to achieve a better performance balance under different charge-discharge states, enabling the electrode to work more stably in subsequent use and reducing performance fluctuations.

[0138] It should be noted that the term "comprising," or any other variation thereof, is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0139] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A method for preparing a high-activity silver oxide cathode material, characterized in that, include: S1. High specific surface area silver nanowire active material was synthesized by a one-pot polyol method. S2. The silver nanowire active material is pressed and sintered into a silver blank electrode using vacuum hot pressing sintering technology. S3. The silver blank electrode is subjected to multi-stage constant current charging formation by ear-type single formation. S4. The electrode after charging and formation is repeatedly cleaned and dried with anhydrous ethanol and deionized water to obtain a highly active silver oxide cathode material.

2. The method of claim 1, wherein the method is characterized by: The one-pot polyol method for synthesizing high specific surface area silver nanowire active materials includes: S11. Weigh out silver nitrate and dissolve it in ethylene glycol solution to prepare silver nitrate ethylene glycol solution; weigh out PVP and dissolve it in ethylene glycol solution to prepare PVP ethylene glycol solution; prepare FeCl3 ethylene glycol solution. S12. Add the ethylene glycol solution to a vacuum reactor, stir and heat; slowly add the PVP ethylene glycol solution dropwise to the reactor; add the FeCl3 ethylene glycol solution control agent; add the silver nitrate ethylene glycol solution, stir continuously, and synthesize silver nanowires; S13. The silver nanowires are post-treated. After the reaction is completed, the reaction vessel is naturally cooled to room temperature. The upper layer of the precipitate is removed, and the reaction product is washed and dispersed with deionized water. The precipitate is separated from the liquid using a high-speed centrifuge. The precipitate is washed with anhydrous ethanol and dried to obtain the post-treated silver nanowires. S14. The post-processed silver nanowires are tested to obtain tested silver nanowires.

3. The method of claim 1, wherein the method is characterized by: The process of pressing and sintering the silver nanowire active material into a silver blank electrode using vacuum hot pressing sintering technology includes: S21. Assemble a graphite module inside a steel frame, ensuring the internal filling space matches the design dimensions of the highly active silver oxide electrode material; tighten external bolts to prevent the mold from falling apart during movement, and place the lower pressure block inside the filling space to obtain a silver blank sintering mold. S22. A silver mesh of the corresponding size is laid flat in the filling space to obtain a current collection material; 24-44g of the silver nanowires are weighed and loaded into the silver blank sintering mold, and the mold is vibrated to make the silver nanowires evenly spread throughout the filling space; a high-purity graphite spacer is placed on the silver nanowires and pre-pressed to obtain a shaped blank. S23. Repeat the process of placing a silver mesh in the filling space, weighing the silver nanowires and loading them into the silver blank sintering mold, and placing a high-purity graphite spacer on the silver nanowires, so that the silver blank sintering mold contains multiple shaped blanks; place the upper pressure block on the filled multiple shaped blanks to obtain the filled silver blank sintering mold. S24, the filled silver blank sintering mold is placed into a hot pressing device, the position of the filled silver blank sintering mold is adjusted, and it is ensured that the upper pressing column of the hot pressing device and the upper pressing block of the filled silver blank sintering mold are on a straight line; the furnace door is closed, the vacuum pump of the hot pressing device is opened, and the vacuum in the furnace is controlled at about 2-8 Pa; after the vacuum reaches the specified requirement, vacuum hot pressing sintering is performed, the pressure is set to 30-70 kN, the sintering temperature is 350-450 DEG C, and the holding time is 10-20 min; after sintering is completed, the hot pressing device is naturally cooled, the vacuum is removed, the sintered silver blank sintering mold is taken out, the mold is demolded after cooling, and a silver blank electrode is obtained.

4. The method of claim 1, wherein the method is characterized by: The multi-stage constant current charging formation of the silver blank through the ear type single formation includes: S31, the silver blank electrode is welded with an ear, and a silver blank electrode ear is obtained; the silver blank electrode ear is connected with an electrode of a formation device, the formation device is a hanging type single formation device, is placed into a formation clamp, and a hanging type formation is formed; the electrode sheet in the formation tank is connected in parallel, n formation batteries are connected, and n is a natural number; two formation tanks are connected in series, so that a plurality of electrodes can be formed at a time, and a formed formation battery is obtained; S32, the formed formation battery is added with a 1.0-1.5 g / mol KOH formation electrolyte at a certain temperature, and the formed formation battery is placed in the electrolyte for 3-8 min, so that the electrolyte and the silver electrode blank are fully contacted and activated, and a formation battery activated by the electrolyte is obtained; S33, the electrolyte activated formation battery, by the formation system for multi-stage constant current charging formation; formation temperature is 75~85℃; formation system is 15~25mA / cm 2 current density charging, charging time is 6~8h, charging capacity reaches 20~40%, reaches AgO generating potential, tank voltage from 1.2~1.5V rises to 1.8~2.0V; small current stage is 8~12mA / cm 2 current density charging, charging time is 12~20h, total charging capacity reaches 120~140%, positive plate voltage reaches platform period, Ag electrode partial pressure increases trend is basically consistent with tank voltage, final voltage 2.0~2.3V; stabilization stage is 2~4mA / cm 2 current density charging 8~12s, 1~3mA / cm 2 current density discharging 3~8s, charge-discharge cycle 800~1200 times, the formation battery of multi-stage constant current charging is obtained.

5. The method of claim 1, wherein the method is characterized by: The high-activity silver oxide cathode material is obtained by repeatedly cleaning the charged and formed electrode with anhydrous ethanol and deionized water, until there is no alkaline on the surface of the electrode, and the dry electrode is obtained. S41, the multi-stage constant current charged formation battery is removed, and repeatedly cleaned with anhydrous ethanol and deionized water until there is no alkaline on the surface of the electrode, and the dry electrode is obtained; S42, the surface moisture of the dry electrode is wiped, and a cleaned electrode material is obtained; S43, the cleaned electrode material is placed in a vacuum drying box for drying treatment, and dried at 80-100 DEG C for 1.5-2.5 h, and a high-activity silver oxide electrode material after drying is obtained.

6. The method of claim 5, wherein the method is characterized by: The preparation method of the high-activity silver oxide cathode material further includes tailoring the high-activity silver oxide electrode material after drying, including: The high-activity silver oxide electrode material after drying is cut along the length direction of each plate by 3-7 mm, so as to reach the size of the silver oxide cathode of the seawater activated battery design, and a high-activity silver oxide electrode material to be detected is obtained.

7. The method of producing a highly active silver oxide cathode material according to claim 6, characterized in that, The preparation method of the high-activity silver oxide cathode material further includes detecting the high-activity silver oxide electrode material to be detected, including: The composition, specific surface area, loose bulk density, appearance quality, size and electrical performance of the high-activity silver oxide electrode material to be detected are detected, and the high-activity silver oxide electrode material is obtained.

8. A high activity silver oxide cathode material, characterized in that, The high-activity silver oxide cathode material is prepared according to the preparation method of any one of claims 1-7.

9. The highly active silver oxide cathode material of claim 8, wherein, The high-activity silver oxide cathode material is assembled with aluminum alloy anode material to form a battery, under the condition of 79-83℃, 4-4.5 mol / L NaOH solution+20 g / L Na2SnO3 solution, the average voltage of the battery is 1.705V at 6.5 min, the current density is 600 mA / cm 2 , the ratio of the actual discharge capacity of the silver oxide cathode to the theoretical discharge capacity is 78.7%; the average voltage of the battery is 1.771V at the current density of 200 mA / cm 2 , the ratio of the actual discharge capacity of the silver oxide cathode to the theoretical discharge capacity is 85.3%.

10. Use of a high-activity silver oxide cathode material, characterized in that The high-activity silver oxide cathode material is prepared by the method according to any one of claims 1-7 or is applied to battery manufacturing, medical equipment and drinking water purification.

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