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

Abstract

The application discloses a kind of high-activity silver oxide cathode material and its preparation method and application, belong to cathode material technical field.The preparation method of high-activity silver oxide cathode material includes: using one-pot polyol method to synthesize high specific surface area silver nanowire active substance;Vacuum hot-pressing sintering technology is used to press sinter silver nanowire active substance into silver blank;Silver blank is charged by multi-stage constant current charging by ear type single mode;After formation, silver electrode is cleaned with anhydrous ethanol, deionized water multiple times and dried to obtain silver oxide electrode to test discharge performance.The silver oxide electrode obtained by the application has a large specific surface area, high porosity, and is easy to fully contact and react with electrolyte, improving the utilization rate of electrode active material and electrode discharge efficiency, shortening the battery activation time, and suitable for application in underwater high-power energy equipment.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of cathode materials, in particular to a high-activity silver oxide cathode material and a preparation method and application thereof. BACKGROUND

[0002] The seawater-activated battery is a battery with a metal or an alloy with electrochemical activity as an anode, a metal chloride, silver oxide or an air electrode as a cathode, and seawater as an electrolyte to achieve the purpose of being used underwater or in a special environment. The seawater-activated battery has the advantages of long dry storage time, good safety, maintenance-free, short activation time, low temperature resistance, and irreplaceable advantages in underwater driving. It can be widely used as an underwater propulsion power source in the fields of underwater unmanned underwater vehicles, electric power torpedoes and other underwater or deep-sea equipment. Silver oxide electrode material is a key material and an important component of the seawater-activated battery, and is also one of the important factors affecting the performance of the seawater-activated battery. The silver oxide (AgO) electrode has a theoretical specific energy of 248 Wh / kg and a resistivity of about 10 -1 Ω / m, has the advantages of high energy density, large specific power and stable working voltage, and the theoretical specific capacity (432 mAh·g -1 ) of AgO is nearly twice that of Ag2O (230 mAh·g -1 ), which is a commonly used cathode material of the seawater-activated battery.

[0003] However, the seawater-activated battery cathode material in the prior art has two main problems. First, the silver oxide cathode material is a disordered grain close-packed structure, and there are fewer pores between the grains. When the seawater-activated battery is discharged at a high power, the OH - ions generated by the silver oxide cathode diffuse slowly, the OH - ions are accumulated inside the electrode, the concentration difference polarization is large, the electrode potential is low, and the utilization rate of the electrode active material is low, resulting in a decrease in the working performance of the seawater-activated battery. Second, during the reaction of the silver oxide cathode material, the surface of the electrode reacts from the outside to the inside layer by layer, first generating monovalent silver oxide (Ag2O), which is an insulator with a resistivity of 10 6 Ω / m, and then generating Ag with a resistivity of about 10 -8 Ω / m. When discharged at a high power, the ohmic polarization of the insulating film of monovalent silver oxide attached to the surface of the silver oxide grain is large, the electrode potential lags seriously, and the activation response is slow. Therefore, based on the above defects, it is urgent to propose a high-activity silver oxide (AgO) cathode material to solve the technical problems in the prior art. SUMMARY

[0004] Based on the above technical problems to be solved by the present application, the present application provides a high-activity silver oxide cathode material and a preparation method and application thereof.

[0005] One of the purposes of the present application is to provide a preparation method of high-activity silver oxide cathode material, comprising: S1, synthesizing high specific surface area silver nanowire active material by one-pot polyol method; S2, pressing and sintering the silver nanowire active material into silver blank electrode by vacuum hot-pressing sintering technology; S3, performing multi-stage constant current charging formation on the silver blank electrode by ear-hanging type single formation; S4, cleaning and drying the charged and formed electrode with anhydrous ethanol and deionized water multiple times to obtain high-activity silver oxide cathode material.

[0006] Further, the high specific surface area silver nanowire active material is synthesized by one-pot polyol method, comprising: 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 ethylene glycol solution into vacuum reaction kettle and stirring and heating; slowly adding the PVP ethylene glycol solution into the reaction kettle; adding the FeCl3 ethylene glycol solution control agent; adding the silver nitrate ethylene glycol solution and continuously stirring to synthesize silver nanowire; S13, post-treating the silver nanowire, after the reaction is completed, naturally cooling the reaction kettle to room temperature; removing the upper solution of the precipitate, washing the reaction product with deionized water and dispersing; separating the precipitate from the liquid by using a high-speed centrifuge; washing the precipitate with anhydrous ethanol and drying to obtain post-treated silver nanowire; S14, detecting the post-treated silver nanowire to obtain detected silver nanowire.

[0007] Further, the silver nanowire active material is pressed and sintered into a silver blank electrode by vacuum hot-press sintering technology, 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; by tightening the external bolts, preventing the mold from scattering during movement, placing a lower pressing block in the filling space, and obtaining a silver blank sintering mold; S22, laying a silver mesh of corresponding size in the filling space to obtain a current collecting material; weighing 24-44 g of silver nanowires and loading them into the silver blank sintering mold, vibrating the mold to make the silver nanowires evenly cover the filling space; placing a high-purity graphite spacer on the silver nanowires and pre-pressing to obtain a formed 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 spacer on the silver nanowires to make the silver blank sintering mold have multiple formed blanks; placing an upper pressing block on the filled multiple formed blanks to obtain a filled silver blank sintering mold; S24, placing the filled silver blank sintering mold into a hot-pressing equipment, adjusting the position of the filled silver blank sintering mold to ensure that the upper pressing column of the hot-pressing equipment and the upper pressing block of the filled silver blank sintering mold are on a straight line to avoid uneven stress caused by the offset of the filled silver blank sintering mold; closing the furnace door, opening the vacuum pump of the hot-pressing equipment, and controlling the vacuum in the furnace to about 2-8 Pa; after the vacuum reaches the specified requirement, vacuum hot-press sintering is performed, the pressure is set to 30-70 kN, the sintering temperature is 350-450℃, and the holding time is 10-20 min; after sintering, the hot-pressing equipment is naturally cooled, the vacuum is removed, the sintered silver blank sintering mold is taken out, and the mold is demolded after cooling to obtain a silver blank electrode.

[0008] Further, the silver nanowire active material is pressed and sintered into a silver blank electrode by vacuum hot-press sintering technology, 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; by tightening the external bolts, preventing the mold from scattering during movement, placing a lower pressing block in the filling space, and obtaining a silver blank sintering mold; S22, laying a silver mesh of corresponding size in the filling space to obtain a current collecting material; weighing 24-44 g of silver nanowires and loading them into the silver blank sintering mold, vibrating the mold to make the silver nanowires evenly cover the filling space; placing a high-purity graphite spacer on the silver nanowires and pre-pressing to obtain a formed 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 spacer on the silver nanowires to make the silver blank sintering mold have multiple formed blanks; placing an upper pressing block on the filled multiple formed blanks to obtain a filled silver blank sintering mold; S24, placing the filled silver blank sintering mold into a hot-pressing equipment, adjusting the position of the filled silver blank sintering mold to ensure that the upper pressing column of the hot-pressing equipment and the upper pressing block of the filled silver blank sintering mold are on a straight line to avoid uneven stress caused by the offset of the filled silver blank sintering mold; closing the furnace door, opening the vacuum pump of the hot-pressing equipment, and controlling the vacuum in the furnace to about 2-8 Pa; after the vacuum reaches the specified requirement, vacuum hot-press sintering is performed, the pressure is set to 30-70 kN, the sintering temperature is 350-450℃, and the holding time is 10-20 min; after sintering, the hot-pressing equipment is naturally cooled, the vacuum is removed, the sintered silver blank sintering mold is taken out, and the mold is demolded after cooling to obtain a silver blank electrode. 2The charging is carried out at a current density, the charging time is 6-8h, the charging capacity reaches 20-40%, reaches the AgO generating potential, and the tank voltage increases from 1.2-1.5V to 1.8-2.0V; the small current stage is 8-12mA / cm 2 The charging is carried out at a current density, the charging time is 12-20h, the total charging capacity reaches 120-140%, the positive plate voltage reaches a platform period, the Ag electrode partial pressure increases trend is basically consistent with the tank voltage, and the final voltage is 2.0V-2.3V; the stabilizing stage is 2-4mA / cm 2 The charging is carried out at a current density, the charging time is 12-20h, the total charging capacity reaches 120-140%, the positive plate voltage reaches a platform period, the Ag electrode partial pressure increases trend is basically consistent with the tank voltage, and the final voltage is 2.0V-2.3V; the stabilizing stage is 2-4mA / cm 2 The charging is carried out at a current density, the charging time is 12-20h, the total charging capacity reaches 120-140%, the positive plate voltage reaches a platform period, the Ag electrode partial pressure increases trend is basically consistent with the tank voltage, and the final voltage is 2.0V-2.3V; the stabilizing stage is 2-4mA / cm

[0009] Further, the electrode after charging is washed with anhydrous ethanol and deionized water, and dried, to obtain the high-activity silver oxide cathode material, comprising: S41, the formed battery is removed, and repeatedly washed with anhydrous ethanol and deionized water until no alkaline is left on the surface of the electrode, to obtain a dry electrode; S42, the surface moisture of the dry electrode is wiped, to obtain a washed electrode material; S43, the washed electrode material is placed in a vacuum drying box for drying treatment, and dried at 80-100 DEG C for 1.5-2.5h, to obtain the high-activity silver oxide electrode material after drying.

[0010] Further, the preparation method of the high-activity silver oxide cathode material further comprises tailoring the high-activity silver oxide electrode material after drying, comprising: the high-activity silver oxide electrode material after drying is cut along the length direction of each plate by 3-7mm, to reach the size of the silver oxide cathode of the seawater activated battery design, and to obtain the high-activity silver oxide electrode material to be detected.

[0011] Further, the preparation method of the high-activity silver oxide cathode material further comprises detecting the high-activity silver oxide electrode material to be detected, comprising: detecting 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, to obtain the high-activity silver oxide electrode material.

[0012] The second object of the application is to provide a high-activity silver oxide cathode material prepared according to the preparation method of the high-activity silver oxide cathode material.

[0013] Further, the high-activity silver oxide cathode material is assembled into a battery with an aluminum alloy anode material, under the condition of 79 DEG C-83 DEG C, 4mol / L-4.5mol / L NaOH solution + 20g / L Na2SnO3 solution, the current density is 600mA / cm 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 silver nanowires 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 hanging type formation battery assembly diagram of an embodiment of the application is shown;

[0026] Figure 7 A silver blank electrode SEM diagram after formation of an embodiment of the application is shown;

[0027] Figure 8 A high-activity silver oxide electrode sample diagram of an embodiment of the application is shown;

[0028] Figure 9 A high-activity silver oxide cathode material current density 600mA / cm 2 discharge voltage curve diagram under the condition;

[0029] Figure 10 A high-activity silver oxide cathode material current density 200mA / cm 2 discharge voltage curve diagram under the condition;

[0030] Wherein, 1, shunt; 2, DC power supply; 3, formation electrolyte; 4, formation tank; 5, silver oxide electrode; 6, auxiliary electrode. DETAILED DESCRIPTION

[0031] Exemplary embodiments of the present application will be described herein below with reference to the accompanying drawings. While exemplary embodiments of the present application are shown in the drawings, it is understood that the present application can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that this application will be thoroughly and completely understood, and so that the scope of the present application will be conveyed completely to those skilled in the art.

[0032] In the following examples, if not specifically indicated, the technical means adopted are conventional means known to those skilled in the art, and the reagents and materials in the present application are obtained from the market or other public channels.

[0033] The high-activity silver oxide cathode material, its preparation method and application described in the present application, the technical principle mainly includes:

[0034] By improving the morphology and size of the active substance of silver oxide (AgO) electrode material, the formation efficiency of the electrode is improved, thereby improving the utilization rate of the electrode; the forming and formation process route of the electrode material is improved, and an electrode material with suitable electrode porosity and excellent organization structure is prepared, which provides more active sites for silver oxide electrode discharge while improving the formation efficiency and utilization rate of the electrode, to meet the performance requirements of high-power battery discharge and shorten the activation time of high-power battery application.

[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, using vacuum hot-pressing sintering technology to press and sinter the silver nanowire active material into a silver blank;

[0050] S3, performing multi-stage constant current charging formation on the silver blank by means of ear type single formation;

[0051] S4, after formation, the electrode is cleaned multiple times with anhydrous ethanol and deionized water and dried to obtain a silver oxide electrode for discharge performance testing.

[0052] Further, a one-pot polyol method is used to synthesize high specific surface area silver nanowire active material, comprising:

[0053] S101, a certain amount of silver nitrate is dissolved in a proper amount of ethylene glycol solution to prepare a silver nitrate ethylene glycol solution with a concentration of 0.1-0.5 mol / L; a certain amount of PVP is dissolved in the ethylene glycol solution to prepare a PVP ethylene glycol solution with a concentration of 0.1-1.0 mol / L; and a 1 mM-10 mM FeCl3 ethylene glycol solution is prepared;

[0054] S102, the ethylene glycol solution is added to a vacuum reaction kettle, and heated to 100-150℃ under magnetic stirring; after the solution temperature is stabilized, the PVP ethylene glycol solution is slowly added to the reaction kettle at a drop rate of 1-5 mL / min; the FeCl3 ethylene glycol solution is added as a control agent; and the silver nitrate ethylene glycol solution is added, and stirring is continued for 1-3 h to synthesize silver nanowires;

[0055] S103, the silver nanowires are post-treated, and after the reaction is completed, the reaction kettle is naturally cooled to room temperature; the upper layer of the precipitate solution is removed, the reaction product is washed with deionized water and dispersed by ultrasonic oscillation; a high-speed centrifuge is used to separate the precipitate from the liquid at a centrifugation rate of 8000-12000 r / min; the precipitate is washed with anhydrous ethanol for 3-5 times; and the precipitate is placed in a vacuum drying oven at 55-65℃ for drying for 1 h to obtain post-treated silver nanowires;

[0056] S104, the post-treated silver nanowire precipitate is comprehensively detected, including observing the morphology and size of the nanowires by TEM and SEM, and analyzing the crystal structure by XRD to obtain detected silver nanowires.

[0057] Further, a one-pot polyol method is used to synthesize high specific surface area silver nanowire active material, comprising:

[0058] S201, a graphite module is assembled in a steel frame, the internal filling space is controlled to be consistent with the design size of the high-activity silver oxide electrode material; the mold is prevented from scattering during movement by tightening the external bolts; and a pressing block is placed in the filling space to obtain a silver blank sintering mold;

[0059] S202, lay a silver mesh of corresponding size in the filling space to obtain a current collecting material; weigh 34 g of the silver nanowires and put them into the silver blank sintering mold, shake the mold to make the silver nanowires evenly cover the filling space; put a high-purity graphite spacer on the silver nanowires and pre-press to obtain a formed blank;

[0060] S203, repeat the process of laying a silver mesh in the filling space, weighing the silver nanowires and putting them into the silver blank sintering mold, and putting a high-purity graphite spacer on the silver nanowires to make the silver blank sintering mold have multiple formed blanks; put an upper pressing block on the filled multiple formed blanks to obtain a filled silver blank sintering mold;

[0061] S204, put the filled silver blank sintering mold into a hot-pressing device, adjust the position of the filled silver blank sintering mold to ensure 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 to avoid uneven stress caused by the deviation of the filled silver blank sintering mold; close the furnace door, open the vacuum pump of the hot-pressing device, and control the vacuum in the furnace to about 5 Pa; after the vacuum reaches the specified requirement, perform vacuum hot-pressing sintering, set the pressure to 50 kN, the sintering temperature to 400°C, and the holding time to 15 min; after sintering, wait for the hot-pressing device to cool naturally, remove the vacuum, take out the sintered silver blank sintering mold, and demold after the mold cools to obtain a silver blank.

[0062] Further, the silver blank is subjected to multi-stage constant-current charging by a hanging ear type singleization, which comprises:

[0063] S301, connect the charging battery tabs to the electrodes of a charging device, which is a hanging type singleization device, put it into a charging clamp to form a hanging type charging; the electrode sheets in the charging tank are connected in parallel, n charging batteries are connected, and n is a natural number; the two charging tanks are connected in series to ensure that multiple groups of electrodes can be charged at a time to obtain an assembled charging battery;

[0064] S302, add a certain temperature of 1.3 g / mol KOH charging electrolyte to the assembled charging battery, and let the assembled charging battery stand in the electrolyte for 5 min to activate the electrolyte and the silver electrode blank to obtain an electrolyte-activated charging battery;

[0065] S303, the electrolyte-activated charging battery is subjected to multi-stage constant-current charging by a charging system; the charging temperature is 81.5°C±1.5°C; the charging system is a large current stage of 20 mA / cm 2The charging current density is 10mA / cm2, the charging time is 6-8h, the charging capacity reaches 30%, reaches the AgO generating potential, and the cell voltage increases from 1.5V to 1.8V; the small current stage is 10mA / cm 2 The charging current density is 10mA / cm2, the charging time is 6-8h, the charging capacity reaches 30%, reaches the AgO generating potential, and the cell voltage increases from 1.5V to 1.8V; the small current stage is 10mA / cm 2 The charging current density is 10mA / cm2, the charging time is 6-8h, the charging capacity reaches 30%, reaches the AgO generating potential, and the cell voltage increases from 1.5V to 1.8V; the small current stage is 10mA / cm 2 The charging current density is 10mA / cm2, the charging time is 6-8h, the charging capacity reaches 30%, reaches the AgO generating potential, and the cell voltage increases from 1.5V to 1.8V; the small current stage is 10mA / cm

[0066] Further, the charged electrode is washed with anhydrous ethanol and deionized water, and dried to obtain a high-activity silver oxide cathode material, comprising:

[0067] S401, the multi-stage constant current charged formation battery is removed, and based on the certain alkalinity, the electrode is repeatedly washed with anhydrous ethanol and deionized water until the electrode surface is not alkaline, and a dry electrode is obtained;

[0068] S402, the dry electrode surface is wiped to obtain a washed electrode material;

[0069] S403, the washed electrode material is placed in a vacuum drying box for drying treatment, and is dried at 125 DEG C for 2h to obtain a high-activity silver oxide electrode material after drying.

[0070] Further, the high-activity silver oxide electrode material after drying is cut along the length direction of each plate by 5mm to reach the size of the silver oxide cathode of the seawater activated battery design, and the edge and corner materials are reserved for performance detection to obtain a high-activity silver oxide electrode material to be detected.

[0071] Further, the composition, specific surface area, bulk density, appearance quality, size, electrical performance and the like of the high-activity silver oxide electrode material to be detected are detected to obtain a high-activity silver oxide electrode material.

[0072] Example 1

[0073] The application provides a high-specific-surface-area silver nanowire preparation test.

[0074] Mainly include:

[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 in the steel frame, control the internal filling space to be consistent with the designed silver oxide size. Tighten the external bolts to prevent the mold from falling apart during movement, and place the lower pressing block in the filling space.

[0086] (2) Place the corresponding size of silver mesh as the current collector material in the filling space.

[0087] (3) Weigh 34g of silver nanowires and place them in the mold, and shake the mold to make the silver nanowire powder evenly cover the filling space.

[0088] (4) Place the high-purity graphite spacer on top of the silver nanowires and press it slightly.

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

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

[0091] (7) Place the filled silver nanowire mold in the specific area of the equipment and adjust the mold position to ensure that the upper pressing column of the hot pressing equipment is in a straight line with the upper pressing block of the mold, avoiding uneven stress caused by mold deviation.

[0092] (8) Close the furnace door and turn on the vacuum pump to control the vacuum in the furnace to about 5 Pa.

[0093] (9) After the vacuum reaches the specified requirement, start vacuum hot pressing sintering, set the pressure to 50 kN, the sintering temperature to 400°C, and the holding time to 15 min.

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

[0095] Results:

[0096] Please refer to Figure 4 , the vacuum hot pressing sintering technology applies pressure and heat in a vacuum environment, which can make the combination between material particles more compact and reduce porosity. The electrodes prepared by ordinary pressing technology have more voids due to insufficient pressure or active material morphology size, etc. The electrodes prepared by sintering technology, although sintered, are not as good as vacuum hot pressing sintering in terms of vacuum and pressure synergy. Therefore, the silver electrode structure prepared by vacuum hot pressing sintering is more compact. In addition, due to the compact structure, the conductivity of the electrode is better and the resistance is smaller, which can efficiently conduct current. The vacuum environment can reduce the occurrence of oxidation and other reactions, so that the electrode remains purer during preparation, thereby improving the chemical stability. The compact structure and good performance also make the electrode more stable during long-term use and less prone to performance degradation and other problems.

[0097] Example 3

[0098] The application provides an oxidation silver electrode polarization test.

[0099] Mainly include:

[0100] (1) The adopted formation device is a hanging single formation: connecting the formation battery tab with the electrode of the formation equipment, and then placing it in the formation clamp to form a hanging formation; the electrode sheet in the tank is connected in parallel, and multiple formation batteries can be connected. The two formation tanks are connected in series to ensure that multiple groups of electrodes can be formed at a time.

[0101] (2) After the formation battery is assembled, 1.3 g / mol KOH formation electrolyte at a certain temperature is added, and the formation battery is placed in the electrolyte for 5 min, so that the electrolyte and the silver electrode blank are fully contacted and activated.

[0102] (3) The formation system adopts two-stage constant-current formation: the formation temperature is 81.5℃±1.5℃; the formation system is charged at 20mA / cm 2 The current density is charged, the charging time is 6-8h, the charging capacity reaches 30%, reaches the AgO generation potential, and the tank voltage rises from 1.5V to 1.8V; the small current stage is charged at 10mA / cm 2 The current density is charged, the charging time is 16h, the total charging capacity reaches 130%, the positive plate voltage reaches the platform period (1.83V-1.96V), the Ag electrode partial pressure increases, and the tank voltage is basically consistent, and the final voltage is 2.1V-2.2V; the stable stage is charged at 3mA / cm 2 The current density is charged for 10s, and the current density is discharged for 5s, and the charging and discharging cycle is 1000 times. 2

[0103] Results:

[0104] Please refer to Figures 5 to 7 , with the increase of the charging degree, the micro-morphology structure of the electrode changes, the silver oxide crystals are gradually generated on the surface of the silver nanowire, and the electrode changes from a loose porous structure to a dense structure.

[0105] The hanging lug type single electrode sheet formation method is used for formation, through the double lug type formation, the contact area between the double lug type and the electrode is increased, the overcurrent area is increased, which is beneficial to the uniform diffusion of the current on the electrode reaction surface, and the reaction rate is improved. The silver electrode is formed by using the hanging formation method, the space of the formation tank is large, the micro-short circuit is small, and because of the design of the electrode fixing frame, the distance between the electrode plates is fixed, which is more beneficial to the uniformization of the formation result.

[0106] ​The charging is carried out by adopting a stage constant current charging method, first, a large current density is charged, when the potential reaches the critical value of oxygen evolution, the current density is reduced by 1 / 2, at this time, the current density is reduced, after a period of charging, the potential reaches the critical value of oxygen evolution, and then the current density is reduced by 1 / 2, and the charging is controlled according to the charging cut-off voltage, so that the formation efficiency is greatly improved, and the blind energy consumption and the electrolyte loss are avoided.

[0107] Example 4

[0108] The application provides a cleaning and drying test.

[0109] Mainly include:

[0110] (1) The removed electrode has certain alkalinity, and is repeatedly cleaned by using deionized water until the electrode surface is free of alkalinity.

[0111] (2) The water on the surface of the dry electrode is wiped.

[0112] (3) The cleaned electrode material is placed in a vacuum drying box for drying treatment, and is dried at 125 DEG C for 2h.

[0113] Results:

[0114] The electrode material is potassium hydroxide formation electrolyte, and has certain alkalinity after formation; during dry storage after being assembled into a battery, the electrode material can absorb water in the air to self-discharge, so that the capacity of the battery is lost and the separator of the battery is damaged, and the cleaning and drying can avoid the result.

[0115] Example 5

[0116] The application provides a cutting and performance test.

[0117] Mainly include:

[0118] (1) The high-activity silver oxide electrode material after drying is cut along the length direction of each plate by 5mm, so that the size of the silver oxide cathode of the seawater activated battery design is achieved, and the edge and corner materials are reserved for product inspection.

[0119] (2) The sample is detected in terms of composition, specific surface area, loose bulk density, appearance quality, size and electrical property.

[0120] Results:

[0121] Please refer to Figure 8 The high-activity silver oxide electrode material after drying can be cut according to requirements, and the high-activity silver oxide electrode material after cutting still has the original characteristics.

[0122] Example 6

[0123] The application provides a performance test experiment for a silver oxide cathode material prepared by a preparation process.

[0124] Mainly include:

[0125] The silver oxide cathode material prepared by the preparation process of the last section is assembled into an Al-AgO battery together with an aluminum alloy negative electrode to perform corresponding performance tests, and the performance test results are as follows:

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

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

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

[0129] Results:

[0130] Please refer to Figure 9 and Figure 10 , the high-activity silver oxide electrode material is discharged at a constant current of 600mA / cm 2 at 81.5±1.5℃, (4-4.5mol / L NaOH+20g / L Na2SnO3) solution, and the average electrode potential is maintained at 1.705V within 6.5min, and the ratio of the actual discharge capacity of the silver oxide electrode to the theoretical capacity is 78.7%. At 81℃±2℃, 4-4.5mol / L strong alkaline electrolyte+20g / L corrosion inhibitor solution, the current density is 200mA / cm 2 , the average voltage of the battery (the anode material is a "high-potential aluminum alloy anode") is maintained at 1.771V within 15min, and the ratio of the actual discharge capacity of the silver oxide electrode material to the theoretical capacity is 85.3%.

[0131] Comparative Example

[0132] Please refer to Table 1, the application provides a comparison experiment of a high-activity silver oxide cathode material and a silver oxide (AgO) electrode directly synthesized by a chemical method, a silver oxide (AgO) electrode synthesized by a chemical in-situ method, a silver oxide (AgO) electrode obtained by an electrochemical formation method, and micron or nano silver powder as an electrode active material.

[0133] Table 1 Comparison experiment results of the high-activity silver oxide cathode of the application

[0134]

[0135]

[0136] The comparison result shows that the silver oxide electrode prepared by the application has a higher discharge voltage, which provides a higher output voltage in a high-power energy device; further, the silver oxide electrode prepared by the application has a shorter activation time, can enter a working state faster, reduces energy loss, and is suitable for a fast response scene; further, the time from starting to stable working of the electrode is shortened, the starting speed of the device is faster, and the endurance or sensitivity performance is better.

[0137] In summary, the high-activity silver oxide electrode provided by the application is prepared by an electrochemical formation method, the preparation process parameters are reasonably controlled, the production cost is low, the efficiency is high, and the method is suitable for large-scale industrial production; the active material is silver nanowire, the prepared silver nanowire has a one-dimensional linear structure, the transmission path of electrons in the silver nanowire is smoother, and the overall conductivity of the material can be improved. The high-activity silver oxide electrode provided by the application has a significant advantage in improving the performance of the electrode and optimizing the preparation process, and can better meet the requirements of high quality and high performance of the silver electrode. The high-activity silver oxide electrode provided by the application is formed by using a hanging ear type single electrode sheet formation method, which is simple to operate and reduces the complex assembly process compared with a pole group type formation; because the formation tank is large and the electrode is fixed in the formation frame, the distance between the electrodes is large, which effectively reduces the occurrence of short circuit, improves the formation quality, and in the hanging ear type formation method, the electrode is independently suspended and is subjected to uniform stress, so that deformation is not easy to occur, which is beneficial to ensuring the consistency and stability of the electrode; the electrode after the hot-pressing sintering is formed by using a large-current charging + small-current charging + stable charging and discharging cycle mode, which improves the production efficiency and reduces the damage to the electrode compared with the traditional large-current charging or pulse charging mode; especially in the stable charging and discharging stage, the silver electrode can achieve a better performance balance in different charging and discharging states, so that the electrode can work more stably in the subsequent use process and the performance fluctuation is reduced.

[0138] It should be noted that the term "comprising" or any other variation thereof is intended to cover a non-exclusive inclusion, such that processes, methods, articles, or devices that comprise a list of elements do not necessarily include only those elements, but can include other elements not expressly listed or inherent to such processes, methods, articles, or devices. Without more limitations, the elements defined by the statement "comprise" do not exclude the presence of additional identical elements in the process, method, article, or device that includes the elements.

[0139] The above is only an embodiment of the application and is not intended to limit the application. Those skilled in the art can make various modifications and changes to the application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the application shall be included in the scope of the claims of the application.

Claims

1. A method for preparing a highly active silver oxide cathode material, characterized in that, include: S1. A one-pot polyol method was used to synthesize high specific surface area silver nanowire active materials, including: 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; S2. Using vacuum hot pressing sintering technology, the silver nanowire active material is pressed and sintered into a silver blank electrode, including: 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. 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; close the furnace door, turn on the vacuum pump of the hot press equipment, and control the vacuum in the furnace at 2~8Pa; after the vacuum reaches the specified requirements, perform vacuum hot pressing sintering, set the pressure to 30~70kN, the sintering temperature to 350~450℃, and the holding time to 10~20min; 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 electrode; S3. Perform multi-stage constant current charging formation on the silver blank electrode using a loop-type single-stage formation method, including: S31. Weld tabs onto the silver blank electrode to obtain silver blank electrode tabs; connect the silver blank electrode tabs to the electrodes of the formation equipment, which is a hanging single formation equipment, placed in a formation fixture to form a suspended formation; the electrode plates in the formation tank are connected in parallel to connect n formation cells, where n is a natural number; the two formation tanks are connected in series to ensure that multiple sets of electrodes are formed at one time to obtain assembled formation cells. S32. Add a 1.0~1.5g / mol KOH electrolyte at a certain temperature to the assembled battery, and let the assembled battery stand in the electrolyte for 3~8 minutes until the electrolyte and silver electrode blank are fully contacted and activated to obtain an electrolyte-activated battery. S33. The electrolyte-activated battery is subjected to multi-stage constant current charging formation using a formation regime; the formation temperature is 75~85℃; the formation regime is a high current stage at 15~25mA / cm. 2 Charging is performed at high current density for 6-8 hours, reaching 20-40% charge and the AgO generation potential, with the cell voltage increasing from 1.2-1.5V to 1.8-2.0V; the low current stage is 8-12mA / cm. 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 consistent with the cell voltage, with a final voltage of 2.0-2.3V. During the stabilization phase, the current density was 2-4 mA / cm². 2 Current density during charging (8-12 seconds): 1-3 mA / cm² 2 Discharge at a current density of 3~8s, charge and discharge cycle 800~1200 times, to obtain a formed battery after multi-stage constant current charging; S4. 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: S41. Remove the formation battery that has undergone multi-stage constant current charging, and repeatedly clean it with anhydrous ethanol and deionized water until there is no alkalinity on the electrode surface to obtain a dry electrode. S42. Wipe the moisture off the surface of the dry electrode to obtain the cleaned electrode material; S43. The cleaned electrode material is placed in a vacuum drying oven for drying at 80℃~100℃ for 1.5~2.5h to obtain a dried high-activity silver oxide electrode material.

2. The method for preparing the highly active silver oxide cathode material according to claim 1, characterized in that, The preparation method of the highly active silver oxide cathode material further includes cutting the dried highly active silver oxide electrode material, including: The dried high-activity silver oxide electrode material is cut by 3-7 mm along its length to achieve the silver oxide cathode size designed for seawater activated batteries, thus obtaining the high-activity silver oxide electrode material to be tested.

3. The method for preparing the highly active silver oxide cathode material according to claim 2, characterized in that, The preparation method of the highly active silver oxide cathode material further includes testing the highly active silver oxide electrode material to be tested, including: The composition, specific surface area, bulk density, appearance quality, size, and electrical properties of the high-activity silver oxide electrode material to be tested are detected to obtain the high-activity silver oxide electrode material.

4. A highly active silver oxide cathode material, characterized in that, The highly active silver oxide cathode material is prepared according to any one of claims 1 to 3.

5. The highly active silver oxide cathode material according to claim 4, characterized in that, The highly active silver oxide cathode material and aluminum alloy anode material are assembled into a battery. Under the conditions of 79℃~83℃ and 4mol / L~4.5mol / L NaOH solution + 20g / L Na2SnO3 solution, the current density is 600mA / cm. 2 At 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%.

6. An application of a highly active silver oxide cathode material, characterized in that, The high-activity silver oxide cathode material prepared according to any one of claims 1 to 3, or the high-activity silver oxide cathode material according to claim 5, can be used in battery manufacturing, medical equipment, and drinking water purification.

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