Palladium-based catalyst-based zinc air battery and preparation method thereof
By adopting a palladium-based catalyst preparation method in zinc air batteries, the problems of poor discharge capacity and reduced discharge rate of zinc air batteries are solved, and a higher discharge rate and capacity are achieved.
Patent Information
- Application Number
- CN202510373791.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-27
- Publication Date
- 2025-06-13
AI Technical Summary
The discharge capacity of zinc air batteries is poor and the discharge rate decreases.
Using a preparation method based on a palladium-based catalyst, a nitrogen-doped tin dioxide/reduced graphene oxide composite powder was prepared through a thermal reaction, and the palladium nanoparticles were loaded through a light reduction reaction to form a nitrogen-doped tin dioxide/reduced graphene oxide composite catalyst supported by a palladium nanoparticles, and a palladium-based catalyst cathode sheet was prepared by combining conductive carbon powder and binder.
The oxygen reduction reaction rate is improved, the conductivity and pore structure of the electrode are enhanced, electron transport and diffusion of ions and gases are promoted, and the discharge rate and capacity are improved.
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Figure CN120149647A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of battery materials, and particularly relates to a zinc-air battery based on a palladium-based catalyst and a preparation method thereof. Background Art
[0002] A zinc-air battery is a metal-air battery that uses zinc metal as the negative electrode and oxygen in the air (or oxygen in the air reacts through an electrolyte) as the positive electrode reactant. Its working principle is based on the oxidation reaction of the zinc anode and the oxygen reduction reaction of the air cathode. When the zinc-air battery works, it needs to obtain oxygen from the environment to promote the oxygen reduction reaction (ORR) of the electrode. The carbon paper itself has porosity and air permeability, which can disperse oxygen inside the electrode and reach the catalytic layer, thus ensuring that the cathode side can continuously contact with the oxygen in the air and realize continuous discharge.
[0003] However, compared with the metal negative electrode of ordinary batteries, the theoretical specific capacity of carbon materials is relatively low. In scenarios where high specific energy density is required, the carbon negative electrode often cannot provide sufficient discharge capacity. Moreover, side reactions are likely to occur on the carbon surface or it is partially oxidized, which will consume a part of the current, resulting in a decrease in Coulomb efficiency, affecting the ion transport rate, and causing a decrease in the discharge rate. Summary of the Invention
[0004] The technical problem to be solved by the present invention is to provide a zinc-air battery based on a palladium-based catalyst and a preparation method thereof, aiming to solve the problems of poor battery discharge capacity and decreased discharge rate.
[0005] To solve the above technical problem, the present invention is implemented as follows. A preparation method of a zinc-air battery based on a palladium-based catalyst is proposed, and the steps include: S1. Dispersing graphene oxide dispersion, tin source, and nitrogen source in a reaction kettle at 180 - 200 °C, and performing a thermal synthesis reaction for 8 - 10 h to obtain a nitrogen-doped tin dioxide / reduced graphene oxide composite powder; S2. Dispersing the nitrogen-doped tin dioxide / reduced graphene oxide composite powder in an organic solvent to obtain a powder dispersion liquid, and performing a photo-reduction reaction on the powder dispersion liquid and a palladium ligand solution to obtain a nitrogen-doped tin dioxide / reduced graphene oxide composite catalyst powder loaded with palladium nanoparticles; S3. Mixing the nitrogen-doped tin dioxide / reduced graphene oxide composite catalyst powder loaded with palladium nanoparticles with conductive carbon powder and a binder to make a palladium-based catalyst cathode sheet, and assembling the palladium-based catalyst cathode sheet and a zinc anode sheet into a zinc-air battery.
[0006] In some embodiments of the present invention, the step S1 includes: S1.1. Disperse graphene oxide in absolute ethanol by ultrasonic treatment for 30 - 60 min, then add a bromine source and a nitrogen source, and continue ultrasonic dispersion for 10 - 20 min to obtain a dispersion liquid. S1.2. Transfer the dispersion liquid to a reaction kettle, seal it, and react at a temperature of 180 - 200 °C for 8 - 10 h. After the reaction is completed, cool it naturally to obtain a solid - liquid mixture. S1.3. Centrifuge the solid - liquid mixture, wash the centrifuged solid with ethanol / deionized water alternately at least six times, and vacuum - dry the collected solid at 50 - 60 °C to obtain a nitrogen - doped tin dioxide / reduced graphene oxide composite powder.
[0007] In some embodiments of the present invention, the bromine source includes at least one of stannous bromide, tin tetrabromide, and ammonium bromide, and the nitrogen source includes at least one of sodium azide, urea, and ammonia water. Calculated by mass ratio, the graphene oxide: the bromine source: the nitrogen source = 1:(0.2 - 2):(0.05 - 0.5).
[0008] In some embodiments of the present invention, step S2 includes: S2.1. Add the nitrogen - doped tin dioxide / reduced graphene oxide composite powder to an ethylene glycol solution, and stir and disperse it at room temperature for 30 min to obtain a powder dispersion liquid. S2.2. Dissolve a palladium source and a ligand in ethylene glycol, and stir well to obtain a palladium - ligand solution. S2.3. Place the powder dispersion liquid on a constant - temperature stirring device at 150 - 160 °C, and at the same time, irradiate it with an LED lamp with a wavelength of 365 - 400 nm. Slowly drop the palladium - ligand solution, while maintaining stirring and illumination. After the dropping is completed, continue to react for 60 min under the same temperature and illumination conditions. After natural cooling, centrifuge, wash, and dry it in sequence to obtain a nitrogen - doped tin dioxide / reduced graphene oxide composite catalyst powder loaded with palladium nanoparticles.
[0009] In some embodiments of the present invention, in step S2, the palladium source includes at least one of palladium acetate, palladium chloride, and potassium tetrachloropalladate. Calculated by mass ratio, the powder dispersion liquid: the palladium - ligand solution = 1:(0.2 - 1).
[0010] In some embodiments of the present invention, step S3 includes: S3.1. First mix the nitrogen - doped tin dioxide / reduced graphene oxide composite catalyst powder loaded with palladium nanoparticles with conductive carbon powder, then add a binder and a solvent, and mix evenly to obtain a cathode coating. S3.2. Coat the cathode coating on a carbon layer, and then dry it at 60 - 80 °C to obtain a palladium - based catalyst cathode sheet. S3.3. Place a hydrophilic diaphragm between the zinc anode sheet and the palladium-based catalyst cathode sheet, add the electrolyte, and after sealing, a zinc-air battery is obtained.
[0011] In some embodiments of the present invention, in the step S3, the binder includes at least one of polyvinylidene fluoride, polytetrafluoroethylene, and styrene-butadiene rubber / carboxymethyl cellulose, and the solvent includes at least one of isopropyl alcohol, ethanol, and N-methylpyrrolidone.
[0012] In some embodiments of the present invention, in the step S3, the electrolyte includes an alkaline main body, a zinc promoter, and a buffer additive. The alkaline main body includes at least one of potassium hydroxide, sodium hydroxide, and lithium hydroxide. The zinc promoter includes at least one of zinc oxide, zinc acetate, and zinc sulfate. The buffer additive includes at least one of sodium dodecyl sulfate, potassium dihydrogen phosphate, ethylenediaminetetraacetic acid, cetyltrimethylammonium bromide, and sodium dihydrogen phosphate.
[0013] The present invention provides a zinc-air battery based on a palladium-based catalyst, which is made by the preparation method of a zinc-air battery based on a palladium-based catalyst as described above. The zinc-air battery includes a palladium-based catalyst cathode sheet, a zinc anode sheet, and an electrolyte; wherein, The palladium-based catalyst cathode sheet serves as the air electrode of the zinc-air battery and undergoes an oxygen reduction reaction during discharge; The zinc anode sheet serves as the negative electrode of the battery, undergoes an oxidation reaction, and provides electrons; The electrolyte provides an ion conduction channel to enable the electron-ion reaction between the palladium-based catalyst cathode sheet and the zinc anode sheet to occur.
[0014] Compared with the prior art, the preparation method of a zinc-air battery based on a palladium-based catalyst in the present invention has the beneficial effects that: Palladium has excellent oxygen reduction activity in alkaline media. After being combined with nitrogen-doped graphene oxide and tin dioxide nanostructures, the electron transfer at the electrode interface becomes smoother, the overpotential required for the reaction decreases, and the oxygen reduction reaction rate increases. A higher oxygen reduction reaction rate means that within the same time, the electrode can consume oxygen and transfer current faster, thereby increasing the discharge rate. The nitrogen-doped tin dioxide / reduced graphene oxide substrate loaded with palladium nanoparticles itself has good conductivity and a suitable pore structure. When combined with conductive carbon to form a three-dimensional conductive framework, it can effectively reduce the internal resistance of the electrode and promote electron transport. At the same time, this porous layered structure also facilitates the penetration of the electrolyte and oxygen, ensuring the rapid diffusion of ions and gases within the electrode and enhancing the discharge performance at high currents. When the oxygen reduction reaction at the cathode is more efficient and the impedance is lower, the oxidation reaction of the zinc anode proceeds smoothly, releasing more electrons for use in the external circuit, thereby increasing the discharge capacity. During high-current density discharge, if the cathode can continuously and rapidly catalyze oxygen reduction, the zinc anode can stably provide a higher discharge current, manifested as an increased discharge rate. Brief Description of the Drawings
[0015] Figure 1 It is a schematic flow chart of a preparation method of a zinc-air battery based on a palladium-based catalyst in an embodiment of the present invention. Detailed Description of the Embodiments
[0016] In order to make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.
[0017] Please refer to Figure 1 , the present invention provides a preparation method of a zinc-air battery based on a palladium-based catalyst, and the steps include: S1. Disperse a graphene oxide dispersion, a tin source, and a nitrogen source in a reaction kettle at 180 - 200 °C, and carry out a thermal reaction for 8 - 10 h to obtain a nitrogen-doped tin dioxide / reduced graphene oxide composite powder.
[0018] S1.1. Disperse graphene oxide in absolute ethanol by ultrasonic treatment for 30 - 60 min, then add a bromine source and a nitrogen source, and continue ultrasonic dispersion for 10 - 20 min to obtain a dispersion.
[0019] The bromine source includes at least one of stannous bromide, tin tetrabromide, and ammonium bromide, and the nitrogen source includes at least one of sodium azide, urea, and ammonia water. Calculated by mass ratio, graphene oxide:bromine source:nitrogen source = 1:(0.2 - 2):(0.05 - 0.5).
[0020] Ultrasound can effectively reduce the stacking and aggregation between graphene oxide sheets, fully expose its specific surface area, and provide more active sites for subsequent reactions. Under ultrasonic assistance, the bromine source and nitrogen source can be in full contact with and dispersed in graphene oxide, avoiding the problem of incomplete local reactions during the subsequent hydrothermal process. Through sufficient ultrasonic dispersion, the oxygen-containing functional groups and defect sites on the surface of graphene oxide sheets are fully combined with the bromine source and nitrogen source, laying a uniform and stable foundation for the formation of tin dioxide crystal nuclei and nitrogen doping.
[0021] S1.2. Transfer the dispersion to a reaction kettle, seal it, and react at a temperature of 180 - 200 °C for 8 - 10 h. After the reaction is completed, let it cool naturally to obtain a solid-liquid mixture.
[0022] The Sn²⁺ provided by the bromine source is oxidized to form SnO 2 nanocrystals under high temperature and high pressure conditions, and grow and attach on the surface or between the sheets of graphene oxide, realizing the effective combination of tin dioxide and the carbon carrier. Under hydrothermal conditions, graphene oxide can be partially reduced to reduced graphene oxide, improving conductivity and stability, and taking into account the electron transport performance of the nanocomposite material. The nitrogen source decomposes at high temperature or reacts with the interface of carbon and tin oxides to form a nitrogen-doped structure, and this doping can further enhance the interaction between the carrier and the metal nanoparticles. The product finally obtained in this step is already a nitrogen-doped tin dioxide / reduced graphene oxide composite, possessing both the stability of metal oxide nanoparticles and the high specific surface area and good conductivity of carbon-based materials.
[0023] S1.3. Centrifuge the solid-liquid mixture, wash the obtained solid with ethanol / deionized water alternately at least six times, and dry the collected solid in a vacuum at 50 - 60 °C to obtain nitrogen-doped tin dioxide / reduced graphene oxide composite powder.
[0024] Through multiple alternate washings, the unreacted residues of the bromine source and nitrogen source and some by-products can be effectively removed, ensuring the product purity and surface cleanliness. Using mild washing and drying conditions (50 - 60 °C) can avoid material agglomeration or excessive decomposition caused by high temperature, providing a stable and controllable framework structure for subsequent metal loading.
[0025] Drying at a lower temperature in a vacuum environment can remove the residues of water and organic solvents, avoid damaging the defect sites and nitrogen-doped structure on the material surface, and is beneficial to maintaining the high specific surface area and active sites of the composite material.
[0026] S1.4. Place the nitrogen-doped tin dioxide / reduced graphene oxide composite powder under a light source at 80 - 100 °C and a wavelength of 365 - 400 nm for illumination for 30 - 60 min.
[0027] Under medium-temperature conditions and ultraviolet / visible light irradiation, the unreacted or residual nitrogen source may be excited, resulting in the formation of more and more stable nitrogen sites on the surface of the composite material. As a semiconductor material, tin dioxide generates photo-generated electrons and holes under irradiation at a suitable wavelength, which secondarily modifies the oxygen vacancies or nitrogen-doped structures on the material surface, making the charge distribution of the carrier more conducive to subsequent metal deposition. Light irradiation helps to remove or transform a small amount of organic matter remaining in the hydrothermal process, further cleaning the surface and providing a better attachment environment for subsequent loading of palladium or other metal nanoparticles. This post-irradiation treatment can provide a more uniform nucleation center for subsequent metal deposition and enhance the overall conductivity and stability of the composite material, laying a more solid foundation for electrocatalytic applications (such as use in the cathode of a zinc-air battery).
[0028] S2. Disperse the nitrogen-doped tin dioxide / reduced graphene oxide composite powder in an organic solvent to obtain a powder dispersion liquid, and perform a photoreduction reaction on the powder dispersion liquid and the palladium ligand solution to obtain a nitrogen-doped tin dioxide / reduced graphene oxide composite catalyst powder loaded with palladium nanoparticles.
[0029] S2.1. Add the nitrogen-doped tin dioxide / reduced graphene oxide composite powder to an ethylene glycol solution, stir and disperse it at room temperature for 30 min to obtain a powder dispersion liquid.
[0030] Ethylene glycol has good wetting and dispersing effects on multiphase powders, enabling the composite powder to form a relatively stable suspension system in the solution and providing a unified reaction interface for subsequent palladium loading. Under stirring, the agglomeration between powder particles is alleviated, the specific surface area is increased, and the active surface of nitrogen-doped tin dioxide / reduced graphene oxide is ensured to fully contact with the palladium precursor. Since the powder dispersion is relatively uniform, light can penetrate the solution during the dropping process to contact more particle surfaces, laying a foundation for subsequent photoreduction deposition of palladium.
[0031] S2.2. Dissolve the palladium source and the ligand in ethylene glycol, stir well to obtain a palladium ligand solution. The palladium source includes at least one of palladium acetate, palladium chloride, and potassium tetrachloropalladate. Calculated by mass ratio, powder dispersion liquid:palladium ligand solution = 1:(0.2 - 1).
[0032] The palladium sources are all palladium compounds in the +2 valence form, that is, they have Pd(II) ions. The ligand forms a soluble or uniformly dispersed palladium complex with the Pd(II) ions through coordination, reducing the spontaneous hydrolysis or non-uniform precipitation of Pd(II) in the solution. During the subsequent photoreduction process, the ligand can effectively inhibit the rapid aggregation of palladium atoms, facilitating the formation of palladium nanoparticles with small particle size and high dispersibility. Preparing it into a palladium ligand solution in advance not only ensures the uniformity during addition but also maintains good mass transfer conditions during the dropping process, providing replicability for small-scale to large-scale preparation.
[0033] S2.3. Place the powder dispersion on a constant temperature stirring device at 150 - 160 °C, and simultaneously irradiate it with an LED lamp with a wavelength of 365 - 400 nm. Slowly dropwise add the palladium ligand solution, while maintaining stirring and illumination during the process. After the addition is completed, continue to react for 60 min under the same temperature and illumination conditions. After natural cooling, perform centrifugation, washing, and drying in sequence to obtain the nitrogen-doped tin dioxide / reduced graphene oxide composite catalyst powder loaded with palladium nanoparticles.
[0034] Under these temperature and illumination conditions, Pd(II) enters the excited state, and the oxidative addition or single-electron transfer process is more likely to occur, quickly reducing Pd(II) to metallic Pd nanoparticles; slowly dropwise adding the palladium ligand solution allows Pd to gradually nucleate and grow on the surface of the carrier, avoiding local supersaturation caused by a one-time addition, and obtaining palladium nanoparticles with a more uniform particle size distribution and a more firmly loaded surface; the pre-existing N-rich active sites on the surface of nitrogen-doped tin dioxide / reduced graphene oxide are more likely to anchor Pd atoms / ions, enabling the loaded palladium nanoparticles to be uniformly dispersed and form a strong interaction with the carrier, improving the subsequent electrochemical stability; under the synergistic action of the effective ligand and illumination, the Pd nanoparticles have good crystallinity, smaller particle size, and a narrow distribution, providing a higher specific surface area and activity for their application in electrocatalytic fields such as the oxygen reduction reaction.
[0035] In this step, it is not necessary to protect with argon throughout the process, reducing safety and operation difficulties, while ensuring the rapid deposition of Pd(II) into small-sized palladium nanocrystals in the excited state. The operation without an argon atmosphere can reduce the investment in gas pipelines, airtight equipment, etc., shortening the preparation time and complexity; the photoreduction can be carried out in an air environment, greatly simplifying the process from laboratory to industrialization and making mass production easier to achieve; it is more compatible with scenarios with certain humidity or ventilation requirements, without strictly controlling an anhydrous and anaerobic environment, and is especially suitable for mobile preparation or repair in distributed or field scenarios; when Pd(II) has a strong self-reduction ability under illumination conditions, a high nucleation rate and a good particle size distribution can be ensured even in an air environment, indicating that the process has stable and efficient reduction characteristics.
[0036] S3. Mix the nitrogen-doped tin dioxide / reduced graphene oxide composite catalyst powder loaded with palladium nanoparticles with conductive carbon powder and a binder to make a palladium-based catalyst cathode sheet, and assemble the palladium-based catalyst cathode sheet and a zinc anode sheet into a zinc-air battery.
[0037] Step S3 includes: S3.1. The nitrogen-doped tin dioxide / reduced graphene oxide composite catalyst powder loaded with palladium nanoparticles is first mixed with the conductive carbon powder, and then an adhesive and a solvent are added, and the mixture is blended evenly to obtain a cathode coating; the adhesive includes at least one of polyvinylidene fluoride, polytetrafluoroethylene, and styrene-butadiene rubber / carboxymethyl cellulose, and the solvent includes at least one of isopropanol, ethanol, and N-methylpyrrolidone.
[0038] By mixing with conductive carbon powder in advance, the palladium-based composite catalyst is fully in contact with the additional conductive material, which facilitates the formation of a uniform conductive network and improves the overall conductivity of the cathode. The adhesive plays a bonding and fixing role in the electrode, allowing the catalyst particles to be firmly attached to the electrode matrix; at the same time, different adhesives can adapt to different alkaline environments and pore structure requirements. Using solvents such as isopropanol, ethanol or N-methylpyrrolidone can dissolve or disperse the adhesive and wet the catalyst particles, making the slurry viscosity easier to control, thereby obtaining a uniform and stable electrode coating.
[0039] S3.2. Coat the cathode coating on the carbon layer, and then dry it at 60-80°C to obtain a palladium-based catalyst cathode sheet.
[0040] Slow drying at a moderate temperature (60-80°C) can remove excess solvent and solidify the adhesive to obtain an electrode layer with both surface density and porosity; the coated cathode sheet has a reasonable distribution between the conductive carbon skeleton, Pd-based composite catalyst and gas channels, which is conducive to the transmission of oxygen, ions and electrons in the electrochemical process; compared with high temperature (>100°C) treatment, drying at 60-80°C can avoid the agglomeration of palladium nanoparticles or the destruction of the carrier structure, retaining a high specific surface area and catalytic activity. The carbon layer is a carbon material with a porous structure such as carbon paper or carbon cloth.
[0041] S3.3, a hydrophilic diaphragm is placed between the zinc anode sheet and the palladium-based catalyst cathode sheet, and an electrolyte is added. After sealing, a zinc-air battery is obtained. The electrolyte includes an alkaline main body, a zinc auxiliary agent and a buffer additive, the alkaline main body includes at least one of potassium hydroxide, sodium hydroxide, and lithium hydroxide, the zinc auxiliary agent includes at least one of zinc oxide, zinc acetate, and zinc sulfate, and the buffer additive includes at least one of sodium dodecyl sulfate, potassium dihydrogen phosphate, ethylenediaminetetraacetic acid, hexadecyltrimethylammonium bromide, and sodium dihydrogen phosphate.
[0042] The palladium-based catalyst cathode acts as an air electrode and undergoes oxygen reduction reaction during discharge, and has good electrochemical activity and corrosion resistance; the zinc anode is oxidized in an alkaline medium to form [Zn(OH) 4 ]² - or Zn² +substances, thereby releasing electrons and realizing the conversion of chemical energy and electrical energy of the metal-air battery; in an alkaline environment, the hydrophilic separator can maintain the uniform penetration of the electrolyte while preventing direct short-circuit between the anode and the cathode; The alkaline matrix can provide high ionic conductivity, reduce internal resistance, and enhance power output; the zinc additive stabilizes the anode and helps maintain the concentration balance of Zn² + in the solution, slow down the anode corrosion and dendrite problems, and improve the battery life; the buffer additive improves the interface and corrosion inhibition, and surfactants such as sodium dodecyl sulfate can improve the electrode surface wetting and reduce hydrogen evolution; buffer salts such as potassium dihydrogen phosphate can stabilize the pH within a certain range; complexing agents such as ethylenediaminetetraacetic acid can inhibit the excessive precipitation of metal ions, slow down the anode corrosion, and thus extend the battery life.
[0043] If the electrode activity declines after long-term use, the cathode can be regenerated by light irradiation and low-temperature annealing again (combined with the supplementation of a very small amount of palladium source or nitrogen source) to repair the problems of local palladium particle shedding or oxidation inactivation. When overhauling the battery, there is no need to disassemble the entire battery structure. The operation method is as follows under the allowable external conditions: If the battery decline is relatively serious, especially when palladium particles fall off or are oxidized and inactivated, a small amount of palladium source and nitrogen source can be added to the cathode surface for supplementation.
[0044] Dissolve the supplemented palladium source and nitrogen source in a solvent (such as ethanol or ethylene glycol), and then evenly coat the surface of the palladium-based catalyst cathode sheet and wait for the solvent to volatilize.
[0045] Place the palladium-based catalyst cathode sheet under a UV / visible light LED light source with an irradiation wavelength range of 365 - 400 nm and a light irradiation time of 30 - 60 min to ensure that the light is evenly distributed on the entire surface of the palladium-based catalyst cathode sheet. During the light irradiation process, the UV light excitation can promote the reduction reaction of Pd(II), promote the nucleation and deposition of new palladium particles on the cathode surface, and restore the catalytic activity of Pd nanoparticles.
[0046] After the light irradiation treatment, transfer the palladium-based catalyst cathode sheet to a temperature control device, heat it to 60 - 100 °C, and maintain this temperature for 30 - 60 min. This step helps to further activate the Pd particles and improve their stability. The low-temperature annealing can help the Pd particles stabilize on the carrier surface and repair the surface defects or particle shedding caused by long-term use or oxidation.
[0047] After the annealing is completed, cool the palladium-based catalyst cathode sheet to room temperature and ensure its surface is dry. Reassemble the electrode into the zinc-air battery and conduct performance tests to check the discharge capacity, stability, and efficiency of the battery.
[0048] The present invention provides a zinc-air battery based on a palladium-based catalyst, which is fabricated by a preparation method of a zinc-air battery based on a palladium-based catalyst. The zinc-air battery includes a palladium-based catalyst cathode sheet, a zinc anode sheet, and an electrolyte; wherein, The palladium-based catalyst cathode sheet serves as the air electrode of the zinc-air battery and undergoes an oxygen reduction reaction during the discharge process; The zinc anode sheet serves as the negative electrode of the battery, undergoes an oxidation reaction, and provides electrons; The electrolyte provides an ion conduction channel to enable the electron-ion reaction between the palladium-based catalyst cathode sheet and the zinc anode sheet.
[0049] The foregoing are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.
Claims
1. A method for preparing a zinc-air battery based on a palladium-based catalyst, characterized in that the steps include: S1, placing a graphene oxide dispersion, a tin source and a nitrogen source in a reactor at 180-200° C., and performing a heat-sealing reaction for 8-10 hours to obtain a nitrogen-doped tin dioxide / reduced graphene oxide composite powder; S2, dispersing the nitrogen-doped tin dioxide / reduced graphene oxide composite powder in an organic solvent to obtain a powder dispersion, and subjecting the powder dispersion and a palladium ligand solution to a light reduction reaction to obtain a nitrogen-doped tin dioxide / reduced graphene oxide composite catalyst powder loaded with palladium nanoparticles; S3, mixing the nitrogen-doped tin dioxide / reduced graphene oxide composite catalyst powder loaded with palladium nanoparticles with conductive carbon powder and a binder to prepare a palladium-based catalyst cathode sheet, and assembling the palladium-based catalyst cathode sheet and a zinc anode sheet into a zinc-air battery.
2. The method for preparing a zinc-air battery based on a palladium-based catalyst according to claim 1, characterized in that: The step S1 comprises: S1.1, ultrasonically disperse graphene oxide in anhydrous ethanol for 30 to 60 minutes, then add bromine source and nitrogen source, and continue ultrasonically dispersing for 10 to 20 minutes to obtain a dispersion; S1.2, transferring the dispersion into a reactor, sealing it and reacting it at a temperature of 180-200°C for 8-10 hours, cooling it naturally after the reaction is completed to obtain a solid-liquid mixture; S1.3, centrifuging the solid-liquid mixture, washing the solid obtained by centrifugation with ethanol / deionized water alternately for at least six times, and vacuum drying the collected solid at 50-60° C. to obtain nitrogen-doped tin dioxide / reduced graphene oxide composite powder.
3. A method for preparing a zinc-air battery based on a palladium-based catalyst according to claim 1 or 2, characterized in that: The bromine source includes at least one of stannous bromide, tin tetrabromide, and ammonium bromide, and the nitrogen source includes at least one of sodium azide, urea, and ammonia water. Calculated by mass ratio, the graphene oxide: the bromine source: the nitrogen source = 1: (0.2~2): (0.05~0.5).
4. The method for preparing a zinc-air battery based on a palladium-based catalyst according to claim 1, characterized in that: The step S2 comprises: S2.1, adding the nitrogen-doped tin dioxide / reduced graphene oxide composite powder into an ethylene glycol solution, stirring and dispersing at room temperature for 30 minutes to obtain a powder dispersion; S2.2, dissolving the palladium source and the ligand in ethylene glycol, and stirring thoroughly to obtain a palladium ligand solution; S2.
3. Place the powder dispersion on a constant temperature stirring device at 150-160°C, and irradiate it with an LED lamp with a wavelength of 365-400nm. Slowly add the palladium ligand solution while maintaining stirring and illumination. After the addition is completed, continue to react for 60 minutes under the same temperature and illumination conditions. After natural cooling, centrifuge, wash, and dry in sequence to obtain a nitrogen-doped tin dioxide / reduced graphene oxide composite catalyst powder loaded with palladium nanoparticles.
5. The method for preparing a zinc-air battery based on a palladium-based catalyst according to claim 4, characterized in that: In the step S2, the palladium source includes at least one of palladium acetate, palladium chloride, and potassium tetrachloropalladate, and the powder dispersion: the palladium ligand solution is calculated by mass ratio = 1: (0.2~1).
6. The method for preparing a zinc-air battery based on a palladium-based catalyst according to claim 1, characterized in that: The step S3 comprises: S3.1, mixing the nitrogen-doped tin dioxide / reduced graphene oxide composite catalyst powder loaded with palladium nanoparticles with conductive carbon powder, adding a binder and a solvent, and blending them evenly to obtain a cathode coating; S3.2, coating the cathode coating on the carbon layer, and then drying at 60-80°C to obtain a palladium-based catalyst cathode sheet; S3.
3. Place a hydrophilic diaphragm between the zinc anode sheet and the palladium-based catalyst cathode sheet, add electrolyte, and after sealing, obtain a zinc-air battery.
7. The method for preparing a zinc-air battery based on a palladium-based catalyst according to claim 6, characterized in that: In step S3, the adhesive includes at least one of polyvinylidene fluoride, polytetrafluoroethylene, and styrene-butadiene rubber / carboxymethyl cellulose, and the solvent includes at least one of isopropyl alcohol, ethanol, and N-methylpyrrolidone.
8. The method for preparing a zinc-air battery based on a palladium-based catalyst according to claim 6, characterized in that: In the step S3, the electrolyte includes an alkaline main body, a zinc auxiliary and a buffer additive, the alkaline main body includes at least one of potassium hydroxide, sodium hydroxide and lithium hydroxide, the zinc auxiliary includes at least one of zinc oxide, zinc acetate and zinc sulfate, the buffer additive includes at least one of sodium dodecyl sulfate, potassium dihydrogen phosphate, ethylenediaminetetraacetic acid, hexadecyltrimethylammonium bromide and sodium dihydrogen phosphate, and the hydrophilic membrane includes at least one of a glass fiber membrane, a cellulose-based membrane and a polyvinyl alcohol membrane.
9. A zinc-air battery based on a palladium-based catalyst, characterized in that: The method for preparing a zinc-air battery based on a palladium-based catalyst according to any one of claims 1 to 8 is used, wherein the zinc-air battery comprises a palladium-based catalyst cathode sheet, a zinc anode sheet and an electrolyte; wherein: The palladium-based catalyst cathode sheet is used as the air electrode of the zinc-air battery to carry out oxygen reduction reaction during the discharge process; The zinc anode sheet acts as the negative electrode of the battery, undergoes oxidation reaction and provides electrons; The electrolyte provides an ion conduction channel to enable an electron-ion reaction between the palladium-based catalyst cathode sheet and the zinc anode sheet.