Modified aqueous zinc ion battery negative electrode material as well as preparation method and application thereof

Abstract

The invention is suitable for the technical field of water-based zinc batteries, and provides a modified water-based zinc ion battery negative electrode material and a preparation method and application thereof, and the preparation method comprises the following steps: heating and melting metal gallium; metal indium is poured into liquid gallium and stirred to be molten, and an alloy solution is obtained; zinc powder is poured into the alloy solution to be stirred until the liquid becomes solid; according to the method, the zinc negative electrode is integrally constructed, zinc dendritic crystal growth is effectively inhibited, the steps are carried out under the condition of an external magnetic field, and the magnetic field intensity of the external magnetic field is 0-0.3 T. According to the method, 0-0.3 T magnetic field intensity is additionally applied while the electrochemical performance of the zinc ion battery is tested, so that ions and electrons are changed into an ordered state from a disordered state under the action of Lorentz force, and meanwhile, the motion trail is changed, so that more active sites can be provided; the interaction of the magnetic field and the electric field enhances the mass transfer of the electrolyte during zinc deposition / dissolution, reduces the polarization of the battery, and realizes the improvement of the cycling stability of the zinc battery.

Description

Technical Field

[0001] The present invention belongs to the technical field of aqueous zinc batteries, and particularly relates to a modified negative electrode material for an aqueous zinc ion battery, a preparation method thereof, and an application thereof. Background Art

[0002] With the improvement of the performance requirements for intelligent electronic devices, the use and storage of electric energy have become the primary issues that people urgently need to face. Among them, aqueous zinc batteries are expected to develop into the next-generation battery energy storage system due to their high theoretical capacity, low cost, high safety, and other advantages. An aqueous zinc ion battery mainly includes several parts such as a negative electrode, a separator, a positive electrode, an electrolyte, and a battery case. The electrode material is the main core part of the battery, which is directly related to important performance indicators such as the energy density and working voltage of the battery. As a negative electrode material, zinc metal has problems such as dendrite growth, hydrogen evolution, corrosion, and passivation, resulting in poor reversibility of the negative electrode and short battery life. These problems seriously hinder the practical application of zinc ion batteries. Therefore, there is an urgent need to develop a simple and practical strategy to solve problems such as zinc negative electrode dendrites, improve the cycle stability of zinc ion batteries, and generally improve their electrochemical performance.

[0003] A magnetic field has the radiation characteristics of waves and particles. A magnetic field exists around a magnet, and the interaction between magnets uses the magnetic field as a medium. Therefore, the two magnets can act without physical contact. Due to the magnetic anisotropy of the phase and crystal of the material, when preparing the material, the magnetic field can be used to adjust the arrangement of the phase and the orientation of the crystal to achieve the purpose of improving the morphology and performance of the material, and can also induce the surface structure of the electrode to be more ordered, providing an effective channel for the transmission of electrons and ions; the magnetic field effect can also induce the magnetohydrodynamic phenomenon in the electrolyte to affect charge transfer and reduce the charge transfer impedance; the interaction between the external magnetic field and the electrode material can not only adjust the intrinsic activity of the material, but also adjust the local environment of the solid-liquid interface, enhance the mass transfer near the electrode surface, broaden the deposition area and position of zinc ions, and make the ions evenly distributed, eliminating the surface unevenness phenomenon caused by the nucleation and growth of the lithium anode with tip dendrites.

[0004] The patent application with the publication number 201610515270.5 discloses "A preparation method and application of magnetic field-regulated Co(OH)₂ materials with different phases", which discloses that a magnetic field is placed in the synthesis of materials, and the phase transformation of the materials is caused by the magnetic field to obtain different Co(OH)₂ phases to improve the electrochemical performance; the patent application with the publication number 201910528751.3 discloses "A preparation method of a magnetic field-induced nickel chloride / polyaniline supercapacitor electrode material", which discloses that an external magnetic field is applied during the electrode preparation process of the material to change the order of arrangement of the material morphology and thus change the electrochemical performance. The above methods all improve the electrochemical performance of the material by changing the morphology through an external magnetic field during the material synthesis, which also proves the feasibility of the influence of the magnetic field on the material morphology. Summary of the Invention

[0005] The purpose of the embodiment of the present invention is to provide a preparation method of a modified aqueous zinc ion battery anode material, aiming to solve the problems proposed in the above background technology.

[0006] The embodiment of the present invention is implemented as follows. A preparation method of a modified aqueous zinc ion battery anode material includes the following steps: Heat and melt metallic gallium, and after heat preservation, naturally cool it to room temperature; Pour metallic indium into the liquid gallium, stir until melted, and after heat preservation, naturally cool it to room temperature to obtain an alloy solution; Pour zinc powder into the alloy solution and stir until the liquid becomes solid; Among them, the above steps are carried out under the condition of an external magnetic field, and the magnetic field intensity of the external magnetic field is 0 - 0.3 T.

[0007] Preferably, the mass ratio of the metallic gallium to the metallic indium is 7 - 9:3 - 1.

[0008] Preferably, the mass ratio of the zinc powder to the liquid alloy is 3 - 5:1 - 3.

[0009] Preferably, in the step of heating and melting the metallic gallium, the temperature is 40 - 60 °C.

[0010] Preferably, in the step of pouring the metallic indium into the liquid gallium and stirring until melted, stir under ultrasonic conditions.

[0011] Another purpose of the embodiment of the present invention is to provide a modified aqueous zinc ion battery anode material, which is prepared by using the above preparation method.

[0012] Another purpose of the embodiment of the present invention is to provide an application of a modified aqueous zinc ion battery anode material in the preparation of a zinc ion battery.

[0013] Preferably, the zinc ion battery includes a negative electrode material, an electrolyte, and a positive electrode material. The negative electrode material includes a modified aqueous zinc ion battery negative electrode material as the negative electrode material. The electrolyte includes 1-2M zinc sulfate, and the positive electrode material is sodium vanadate.

[0014] Preferably, the electrolyte includes 1-2M sodium sulfate.

[0015] A preparation method of a modified aqueous zinc ion battery negative electrode material provided by an embodiment of the present invention obtains a gallium-indium liquid precursor through liquid-phase stirring, and then adds zinc powder thereto while stirring. A gallium-indium-zinc negative electrode is prepared by an integrated solid solution method. This negative electrode material has large voids, providing more zinc storage sites, enabling the electrode material to have a large specific capacity and good conductivity. The addition of indium reduces the melting point of gallium, making it more likely to become liquid at room temperature, which is beneficial to dissolve into other materials. At the same time, gallium and zinc can form intermetallic compounds, and indium and zinc exist in part as simple substances. Such a structure is more conducive to ion transport and reduces the growth of zinc dendrites caused by uneven distribution of zinc powder; By performing an external magnetic field treatment during the material preparation, the weak magnetic field provided by a permanent magnet causes ions and electrons to change from a disordered state to an ordered state under the action of the Lorentz force, and at the same time, the movement trajectories change, which can inhibit the growth of zinc dendrites in the zinc ion battery, thereby obtaining an aqueous zinc ion battery with excellent electrochemical performance. Description of the Drawings

[0016] Figure 1 It is a SEM diagram of a modified aqueous zinc ion battery negative electrode material provided by an embodiment of the present invention; Figure 2 It is a battery cycle performance test diagram of Batteries 1, 2, and 3 provided by an embodiment of the present invention; Figure 3 It is a battery cycle performance test diagram of Batteries 1, 4, and 5 provided by an embodiment of the present invention. Detailed Embodiments

[0017] 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 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.

[0018] A modified aqueous zinc ion battery negative electrode material, and its preparation method includes the following steps: 1) Weigh an appropriate amount of solid gallium into a sample box, heat the metal to 40-60 °C using a heating table, continuously stir in the same direction to completely melt the solid metal, keep it warm for 3-5 minutes, and then naturally cool it to room temperature; 2) Cut indium metal into metal grains (scrape off the surface oxide film before cutting), weigh a certain weight of indium metal, the mass ratio of gallium to indium is 3:1, pour the indium grains into liquid gallium, and continuously stir in the same direction under ultrasonic action (the ultrasonic time is 5 - 10 minutes) to completely melt the indium grains. After the indium grains are completely melted, continue to stir to make the components uniform, keep warm for 3 - 5 minutes, and then naturally cool to room temperature; 3) Add zinc powder to the above alloy solution while stirring until the liquid becomes solid; 4) Cut and press the obtained zinc alloy to obtain a zinc negative electrode sheet; The above steps are carried out under the condition of an external magnetic field. The magnetic field is provided by two ferrite magnets with different magnetic field intensities in the shape of a 2×4 cm rectangle and a thickness of 2×4 cm. The distance between the two magnets is 60 mm. The magnetic field intensity is measured by a Tesla meter to be 0 - 0.3 T, and the magnetic field distribution is uniform.

[0019] The following describes the specific implementation of the present invention in detail in combination with specific embodiments.

[0020] Example 1. A modified aqueous zinc ion battery negative electrode material, and its preparation method includes the following steps: 1) Place 1.5 g of solid gallium metal in a sample box, heat the metal to 50 °C using a heating table, and continuously stir in the same direction to obtain a molten liquid metal solution; 2) Cut indium metal into metal grains (scrape off the surface oxide film before cutting). Weigh 0.5 g of indium metal, pour the indium grains into liquid gallium, and continuously stir in the same direction under ultrasonic action to completely melt the indium grains. After the indium grains are completely melted, continue to stir to make the components uniform; 3) Add 4 g of zinc powder to the above alloy solution, and add and stir under ultrasonic action until the solution solidifies to obtain an integrated gallium-indium-zinc alloy.

[0021] Example 2. A modified aqueous zinc ion battery negative electrode material, and its preparation method includes the following steps: 1) Place 0.75 g of solid gallium metal in a sample box, heat the metal to 50 °C using a heating table, and continuously stir in the same direction to obtain a molten liquid metal solution; 2) Cut indium metal into metal grains (scrape off the surface oxide film before cutting). Weigh 0.25 g of indium metal, pour the indium grains into liquid gallium, and continuously stir in the same direction under ultrasonic action to completely melt the indium grains. After the indium grains are completely melted, continue to stir to make the components uniform; 3) Add 4 g of zinc powder to the above alloy solution, and add and stir under ultrasonic action until the solution solidifies to obtain an integrated gallium-indium-zinc alloy.

[0022] Example 3. A modified aqueous zinc ion battery negative electrode material, and its preparation method includes the following steps: 1) Place 2.25 g of solid gallium metal in a sample box, heat the metal to 50 °C using a heating stage, and continuously stir in the same direction to obtain a molten liquid metal solution; 2) Cut indium metal into metal grains (scrape off the surface oxide film before cutting), weigh 0.75 g of indium metal, pour the indium grains into the liquid gallium, and continuously stir in the same direction under ultrasonic action until the indium grains are completely melted. After the indium grains are completely melted, continue stirring to make the components uniform; 3) Add 4 g of zinc powder to the above alloy solution, add and stir simultaneously under ultrasonic action until the solution solidifies to obtain an integrated gallium-indium-zinc alloy.

[0023] Example 4: Compared with Example 1, the only difference is that the amount of zinc powder is adjusted to 3 g.

[0024] Example 5: Compared with Example 1, the only difference is that the amount of zinc powder is adjusted to 5 g.

[0025] Example 6: Compared with Example 1, the only difference is that a magnetic field of 0.15 T is externally applied during steps 2) and 3).

[0026] Example 7: Compared with Example 1, the only difference is that a magnetic field of 3 T is externally applied during steps 2) and 3).

[0027] Application example: Using the integrated gallium-indium-zinc alloys prepared in Example 1 and Examples 4 to 7 as the negative electrode active materials respectively, mix sodium vanadate, conductive agent acetylene black, and binder PVDF in a mass ratio of 7:2:1 and coat it on a stainless steel mesh to prepare the positive electrode; then use 2 M zinc sulfate and 1 M sodium sulfate as the electrolyte to assemble a button-type aqueous zinc-ion battery; label them as Battery 1 to Battery 5 respectively.

[0028] Morphology characterization: Perform scanning electron microscopy analysis on the material prepared in Example 1, and the results are as Figure 1 shown. It can be seen that the surface structure has directional growth in a certain direction, and at the same time has more voids, increasing the specific surface area of the material, providing more active sites, and being conducive to ion transport; Electrochemical test: Perform electrochemical analysis on Battery 1, Battery 2, and Battery 3, and the results are as Figure 2 shown. It can be seen that the zinc-ion battery with a ratio of 1.5:0.5:4 has excellent performance, and the capacity reaches 195 mAh g − 1 , at a current density of 1 A g -1Under this condition, there is still a capacity retention rate of 68.6%. This is because at this ratio, most of the gallium and zinc form intermetallic compounds, increasing the capacity; the remaining zinc and indium create voids in the material structure, which is beneficial for constructing ion transport channels, promoting ion transport, and maintaining its good cycle stability; Electrochemical analysis was performed on Battery 1, Battery 4, and Battery 5, and the results are as Figure 3 shown. It can be seen that the electrochemical performance of the zinc-ion batteries prepared under the condition of an external magnetic field has been improved to a certain extent. Under the condition of an external magnetic field, ions and electrons change from a disordered state to an ordered state under the action of the Lorentz force, and at the same time, their movement trajectories change, which has a great impact on the morphology and growth direction of the material. Furthermore, it has a positive impact on the electrochemical performance of the material. In particular, the zinc-ion battery prepared under the condition of an external magnetic field of 0.15 T has a large capacity of 221 mAh g − 1 and a capacity retention rate of 76.9% at a current density of 1 A g -1 . From this, it can be further known that the external magnetic field has a certain promoting effect on the electrochemical performance of the material during material preparation.

[0029] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A preparation method of a modified aqueous zinc ion battery anode material, characterized in that, It includes the following steps: Heat and melt gallium metal, and after heat preservation, naturally cool it to room temperature; Pour indium metal into the liquid gallium, stir until melted, and after heat preservation, naturally cool it to room temperature to obtain an alloy solution; Pour zinc powder into the alloy solution and stir until the liquid becomes solid; Among them, the above steps are carried out under the condition of an external magnetic field, and the magnetic field intensity of the external magnetic field is 0 - 0.3 T.

2. The preparation method of the modified aqueous zinc-ion battery anode material according to claim 1, characterized in that, The mass ratio of the gallium metal to the indium metal is 7 - 9:3 - 1.

3. The preparation method of the modified aqueous zinc-ion battery anode material according to claim 1, characterized in that, The mass ratio of the zinc powder to the liquid alloy is 3 - 5:1 - 3.

4. The preparation method of the modified aqueous zinc ion battery anode material according to claim 1, characterized in that, In the step of heating and melting the gallium metal, the temperature is 40 - 60 °C.

5. The preparation method of the modified aqueous zinc-ion battery anode material according to claim 1, characterized in that, In the step of pouring the indium metal into the liquid gallium and stirring until melted, stir under ultrasonic conditions.

6. A modified negative electrode material for aqueous zinc ion batteries, characterized in that, It is prepared by using the preparation method described in any one of claims 1 - 5.

7. Application of a modified aqueous zinc ion battery negative electrode material as described in claim 6 in the preparation of a zinc ion battery.

8. The application according to claim 7, characterized in that, The zinc ion battery includes a negative electrode material, an electrolyte, and a positive electrode material. The negative electrode material includes a modified aqueous zinc ion battery negative electrode material as the negative electrode material. The electrolyte includes 1 - 2 M zinc sulfate, and the positive electrode material is sodium vanadate.

9. The application according to claim 8, wherein The electrolyte includes 1 - 2 M sodium sulfate.

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