Solid-liquid interface layer and application thereof in aqueous battery

Abstract

The invention provides a solid-liquid interface layer and application thereof in an aqueous battery, specifically, the solid-liquid interface layer covers the surface of an electrode, and the solid-liquid interface layer is composed of a clay material. The solid-liquid interface layer can be used for a secondary aqueous battery and is not limited to be applied to an aqueous battery. The solid-liquid interface layer is low in raw material cost and simple in process, and can be used for large-scale industrial production. The solid-liquid interface layer has universality to different secondary aqueous battery positive electrode materials, and the prepared battery is good in electrochemical performance and excellent in cycle performance.

Description

Technical Field

[0001] This invention belongs to the field of energy materials, specifically relating to a solid-liquid interface layer and its application in aqueous batteries. Background Technology

[0002] Aqueous zinc-ion batteries (AZIBs) utilize zinc as the negative electrode, which boasts high specific capacity (820 mAh g⁻¹), low redox potential (-0.76 V vs. SHE), and is inexpensive and stable. This gives them irreplaceable advantages, making them stand out among numerous novel aqueous rechargeable metal-ion batteries and becoming the most popular research subject in the field. Furthermore, zinc is one of the most promising choices for scalable micro-energy storage devices, meeting the stringent requirements of flexible and wearable batteries, including high safety, economy, sustainability, and reliable power supply. Summary of the Invention

[0003] The inventors have discovered that in most reported aqueous secondary batteries, additives are added to the aqueous electrolyte to regulate the dissolution and deposition behavior of the cathode material to maintain the battery's electrochemical performance. Additionally, some existing aqueous secondary batteries employ cathode material modification to improve cycle performance. The present invention offers advantages through detailed independent claims. However, for solutions using electrolyte additives, the improvement in cycle performance is limited, and the additives are costly. For solutions using material modification, the preparation process is complex, raw material costs are high, and yields are low. Furthermore, current existing technologies are not easily reproducible and lack universality for cathode materials in aqueous secondary batteries. Based on the above findings, this invention aims to provide a solid-liquid interface layer that can be used in aqueous secondary batteries, but is not limited to aqueous batteries. This solid-liquid interface layer has low raw material costs, a simple process, and can be used for large-scale industrial production. This solid-liquid interface layer has universality for different cathode materials in aqueous secondary batteries, and the prepared batteries exhibit good electrochemical performance and excellent cycle performance.

[0004] In a first aspect, the present invention provides a solid-liquid interface layer for an electrode surface. According to an embodiment of the invention, the solid-liquid interface layer covers the electrode surface and is composed of a clay material. The solid-liquid interface layer according to the embodiment of the invention can be used in, but is not limited to, aqueous batteries. This solid-liquid interface layer has low raw material cost, simple processing, and can be used for large-scale industrial production. This solid-liquid interface layer has universality for different cathode materials in aqueous batteries, and the prepared batteries exhibit good electrochemical performance and excellent cycle performance.

[0005] According to embodiments of the present invention, the above-mentioned solid-liquid interface layer on the electrode surface may further include at least one of the following additional technical features:

[0006] According to an embodiment of the present invention, the clay material is composed of one or more raw materials selected from diatomite, kaolinite, halloysite, montmorillonite, illite, vermiculite, sepiolite, diatomite, and palygorskite.

[0007] According to an embodiment of the present invention, the thickness of the solid-liquid interface layer is 0.05 mm to 1 mm, such as 0.05 mm, 0.1 mm, 0.5 mm and 1 mm, etc. This thickness range is beneficial for controlling the wettability of the sheet.

[0008] In another aspect, the present invention provides a method for preparing a solid-liquid interface layer on an electrode surface. According to an embodiment of the present invention, the method includes: pressing powdered clay material to obtain a sheet; sintering the sheet to obtain a sintered layer; and covering the sintered sheet onto the electrode surface to obtain a solid-liquid interface layer on the electrode surface. This preparation process is simple, can be mass-produced industrially, is inexpensive, exhibits good electrochemical performance, high specific capacity, and excellent cycle performance.

[0009] According to embodiments of the present invention, the above method may further include at least one of the following additional technical features:

[0010] According to an embodiment of the present invention, the clay material is composed of one or more raw materials selected from diatomite, kaolinite, halloysite, montmorillonite, illite, vermiculite, sepiolite, diatomite, and palygorskite.

[0011] According to an embodiment of the present invention, the powdered clay material is obtained by grinding raw clay material.

[0012] According to an embodiment of the present invention, the grinding process is carried out by ball milling at a speed of 1000 rpm to 800 rpm for 1 hour to 8 hours. The inventors have found that this range of speed and time is advantageous for controlling the particle size of the clay material.

[0013] According to an embodiment of the invention, the pressing process is carried out at a pressure of 1000 psi to 8000 psi. The inventors have found that this pressure range is advantageous for controlling the compaction density of the synthetic sheets.

[0014] According to an embodiment of the present invention, the thickness of the sheet is 0.05 mm to 1 mm. The inventors have found that this thickness range is advantageous for controlling the wettability of the sheet.

[0015] According to an embodiment of the present invention, the sintering temperature is 200℃-800℃. The inventors have found that this temperature range is advantageous for controlling the strength and water content of the sheet.

[0016] Optionally, the heating rate of the sintering process is 1-20°C / min. The inventors have found that this range of heating rates is advantageous for controlling the strength and water content of the sheets.

[0017] Optionally, the sintering process is carried out for 2 to 10 hours. The inventors have found that this time range is advantageous for controlling the strength and water content of the sheets.

[0018] Optionally, the thickness of the solid-liquid interface layer is 0.05 mm to 1 mm, such as 0.05 mm, 0.1 mm, 0.5 mm and 1 mm, etc. This thickness range is beneficial for controlling the wettability of the sheet.

[0019] In another aspect, the present invention also provides a method for preparing a solid-liquid interface layer on an electrode surface. According to an embodiment of the present invention, the method includes mixing a powdered clay material with a binder to obtain a mixture, preparing the mixture into a slurry, and spin-coating the slurry onto the electrode surface to obtain a solid-liquid interface layer on the electrode surface.

[0020] According to embodiments of the present invention, the above method may further include at least one of the following additional technical features:

[0021] According to an embodiment of the present invention, the clay material is composed of one or more raw materials selected from diatomite, kaolinite, halloysite, montmorillonite, illite, vermiculite, sepiolite, diatomite, and palygorskite.

[0022] According to an embodiment of the present invention, the powdered clay material is obtained by grinding raw clay material.

[0023] According to an embodiment of the present invention, the grinding process is carried out by ball milling at a speed of 1000 rpm to 800 rpm for 1 hour to 8 hours.

[0024] According to embodiments of the present invention, the adhesive is methylcellulose, hydroxypropylcellulose, ethylcellulose, povidone, or copovidone.

[0025] According to an embodiment of the present invention, the mass ratio of the powdered clay material to the binder is (9.5-7.5):(0.5-2.5), for example, 9.5:0.5, 9:1, 8.5:1.5, 8:2, 7.5:2.5, etc.

[0026] According to an embodiment of the present invention, the mass ratio of the powdered clay material to the binder is 9.5:0.5.

[0027] According to an embodiment of the present invention, the mixing process is carried out at a rotation speed of 1000 rpm to 5000 rpm. The inventors have found that this rotation speed range is advantageous for controlling the particle size of the clay material.

[0028] According to an embodiment of the present invention, the spin coating is performed in a benchtop spin coater with an output power of 60 watts and a suction cup diameter of 2 cm to 16 cm.

[0029] In another aspect of the invention, the invention proposes the application of the electrode surface solid-liquid interface layer described above or the electrode surface solid-liquid interface layer obtained according to the method described above in the preparation of battery electrodes.

[0030] According to embodiments of the present invention, the above application may further include at least one of the following additional technical features:

[0031] According to an embodiment of the present invention, the battery is an aqueous battery.

[0032] According to an embodiment of the present invention, the electrode is a positive electrode material.

[0033] According to an embodiment of the present invention, the positive electrode material is a manganese-based material or a vanadium-based material.

[0034] According to an embodiment of the present invention, the manganese-based material is manganese dioxide, lithium manganate, or zinc manganate.

[0035] According to an embodiment of the present invention, the vanadium-based material is vanadium pentoxide or sodium vanadate.

[0036] According to an embodiment of the present invention, the electrode is a negative electrode material.

[0037] According to an embodiment of the present invention, the negative electrode material is a zinc-based material.

[0038] According to an embodiment of the present invention, the zinc-based material is a negative electrode made of zinc foil or zinc powder, or a negative electrode material made of a zinc-containing alloy.

[0039] 1. In another aspect, the present invention also provides a method for preparing a solid-liquid interface layer on an electrode surface. According to an embodiment of the present invention, the method includes:

[0040] The first method: fabricating a thin sheet and attaching it to the surface of the positive electrode.

[0041] First stage: Mix a certain amount of one or more of the above-mentioned material powders, and mix them evenly by stirring, grinding, ball milling, etc. Preferably, ball mill at a speed of 100-800 rpm for 1-8 hours to obtain the desired powder sample.

[0042] The second stage involves pressing the obtained powder sample into a sheet with a thickness of 0.1 mm to 2 mm under a pressure of 1000-8000 psi.

[0043] The third stage: The resulting sheet is sintered at a temperature of 200℃-800℃ for 2-10 hours, with a heating rate of 1-20℃ / minute. (The purpose is to improve the mechanical strength of the sheet.)

[0044] Fourth stage: Cover the obtained sheet onto the surface of the battery's positive electrode.

[0045] In another aspect, the present invention also provides a method for preparing a solid-liquid interface layer on an electrode surface. According to an embodiment of the present invention, the method includes...

[0046] The second method involves preparing a slurry that adheres to the surface of the cathode material particles.

[0047] First stage: Mix a certain amount of one or more of the above-mentioned clay materials evenly by stirring, grinding, ball milling, etc. Preferably, ball mill at a speed of 100-800 rpm for 1-8 hours to obtain the desired powder.

[0048] Second stage: Mix 95% by weight of powder with 5% by weight of binder, and slurry the powder at a speed of 1000-5000 rpm.

[0049] The third stage involves spin-coating the slurry onto the surface of the cathode material particles to obtain a cathode material coated with an electrolyte layer.

[0050] According to embodiments of the present invention, in the secondary aqueous battery prepared with the above-described battery materials, the main reason for battery performance degradation is the dissolution and deposition process of the positive electrode material during cycling, which gradually transforms into a crust that loses electrochemical activity, ultimately leading to the depletion of the positive electrode active material. The clay surface carries a large number of negatively charged groups, which can attract cations in the solution. During charging, cations dissolve from the positive electrode and are bound near the clay. In the subsequent discharge process, this reduces the amount of cations deposited back to the positive electrode, thereby reducing the possibility of crust formation on the positive electrode and maintaining the presence of active material, thus extending the battery's cycle stability. Attached Figure Description

[0051] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0052] Figure 1 This is a flowchart of an embodiment of the present invention, wherein the artificial electrolyte layer is a solid-liquid interface layer;

[0053] Figure 2This is a diagram showing the cycle performance and coulombic efficiency according to Embodiment 1 of the present invention;

[0054] Figure 3 This is a diagram showing the cycle performance and coulombic efficiency according to Embodiment 2 of the present invention;

[0055] Figure 4 This is a diagram showing the cycle performance and coulombic efficiency according to Embodiment 3 of the present invention;

[0056] Figure 5 The diagram shows the cycle performance and coulomb efficiency of Comparative Example 1 according to the present invention.

[0057] Figure 6 The diagram shows the cycle performance and coulombic efficiency of Comparative Example 2 according to the present invention. Detailed Implementation

[0058] The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the invention, and should not be construed as limiting the invention.

[0059] Example 1

[0060] (1) Using an appropriate amount of kaolin as raw material, after ball milling at 400 rpm for 2 hours, the powder is pressed into a sheet with a thickness of 0.5 mm under a pressure of 8000 psi.

[0061] (2) Take the thin sheet from (1), heat it to 400°C in air at a heating rate of 10°C / min, keep it at that temperature for 4 hours, and after natural cooling, obtain the required material and cover it on the surface of the positive electrode.

[0062] (3) Battery assembly: Positive electrode: α-phase manganese dioxide; Negative electrode: zinc foil;

[0063] Separator: Adsorbed glass fiber mat type separator (AGM separator); Electrolyte: A mixed aqueous solution of 1.8 mol / L zinc sulfate and 0.2 mol / L manganese sulfate. After fully immersing the AGM separator in the liquid electrolyte, it is combined with the above-mentioned positive electrode material covered with artificial electrolyte sheet and negative electrode Zn foil to assemble the battery.

[0064] (4) Battery test:

[0065] Equipped with an artificial electrolyte layer: At 25°C, the battery's initial discharge specific capacity at 0.2C rate is 79.8 mA·h / g. After 23 charge-discharge cycles, the capacity increases to 310.7 mA·h / g, and after 200 cycles, the capacity retention rate is 85%. The average coulombic efficiency is 99.5%.

[0066] Battery cycle performance and coulombic efficiency, such as Figure 2 As shown.

[0067] Example 2

[0068] (1) Kaolin and halloysite were mixed at a mass ratio of 1:1 and ball-milled at 800 rpm for 6 hours. The powder was then pressed into a sheet with a thickness of 0.5 mm under a pressure of 8000 psi.

[0069] (4) Take the thin sheet from (1), heat it to 800°C in air at a heating rate of 10°C / min, keep it at that temperature for 4 hours, and after natural cooling, obtain the required material and cover it on the surface of the positive electrode.

[0070] (3) Battery assembly: Positive electrode: ε-phase manganese dioxide; Negative electrode: zinc foil;

[0071] Separator: Adsorbed glass fiber mat type separator (AGM separator); Electrolyte: A mixed aqueous solution of 1.8 mol / L zinc sulfate and 0.2 mol / L manganese sulfate. After fully immersing the AGM separator in the liquid electrolyte, it is combined with the above-mentioned positive electrode material covered with artificial electrolyte sheet and negative electrode Zn foil to assemble the battery.

[0072] (5) Battery test:

[0073] Equipped with an artificial electrolyte layer: At 25°C, the battery's initial discharge specific capacity at 0.5C rate is 45.0 mA·h / g. After 32 charge-discharge cycles, the capacity increases to 122.8 mA·h / g, and after 920 cycles, the capacity retention rate is 94%. The average coulombic efficiency is 99.68%.

[0074] Battery cycle performance and coulombic efficiency, such as Figure 3 As shown.

[0075] Example 3

[0076] 1) Using an appropriate amount of kaolin as raw material, ball mill at 400 rpm for 2 hours, then press the powder into a sheet with a thickness of 1 mm under a pressure of 8000 psi.

[0077] (2) Take the thin sheet from (1), heat it to 550°C in air at a heating rate of 10°C / min, keep it at that temperature for 4 hours, and after natural cooling, obtain the required material and cover it on the surface of the positive electrode.

[0078] (3) Battery assembly: Positive electrode: β-phase manganese dioxide; Negative electrode: zinc foil;

[0079] Separator: Adsorbed glass fiber mat type separator (AGM separator); Electrolyte: A mixed aqueous solution of 1.8 mol / L zinc sulfate and 0.2 mol / L manganese sulfate. After fully immersing the AGM separator in the liquid electrolyte, it is combined with the above-mentioned positive electrode material covered with artificial electrolyte sheet and negative electrode Zn foil to assemble the battery.

[0080] (4) Battery test:

[0081] Equipped with an artificial electrolyte layer: At 25°C, the battery's initial discharge specific capacity at 0.5C rate is 241.8 mA·h / g, and after 200 charge-discharge cycles, the capacity retention is 94%. The average coulombic efficiency is 99.5%.

[0082] Battery cycle performance and coulombic efficiency, such as Figure 4 As shown.

[0083] Comparative Example 1

[0084] Without an artificial electrolyte layer: Under the exact same test conditions as in Example 1, the initial discharge specific capacity was 187.1 mA·h / g, reaching a peak of 352.7 mA·h / g after 11 charge-discharge cycles. After 200 cycles, the capacity retention was only 20.9%. The average coulombic efficiency was 98.9%. Battery cycle performance and coulombic efficiency are as follows... Figure 5 As shown.

[0085] Comparative Example 2

[0086] Without an artificial electrolyte layer: Under the exact same test conditions as in Example 2, the initial discharge specific capacity was 71.3 mA·h / g, reaching a peak of 215.7 mA·h / g after 23 charge-discharge cycles. After 920 cycles, the capacity retention was only 12.8%. The average coulombic efficiency was 99.1%. Battery cycle performance and coulombic efficiency are as follows... Figure 6 As shown.

[0087] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0088] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A solid-liquid interface layer on an electrode surface, characterized in that, A solid-liquid interface layer is applied to the electrode surface, and the solid-liquid interface layer is composed of clay material.

2. The solid-liquid interface layer on the electrode surface according to claim 1, characterized in that, The clay material is composed of one or more raw materials selected from diatomite, kaolin, halloysite, montmorillonite, illite, vermiculite, sepiolite, diatomite, and palygorskite; Optionally, the thickness of the solid-liquid interface layer is 0.05 mm to 1 mm.

3. A method for preparing a solid-liquid interface layer on an electrode surface, characterized in that, The process includes pressing powdered clay material to obtain a sheet, sintering the sheet to obtain a sintered sheet, and covering the sintered sheet onto the electrode surface to obtain a solid-liquid interface layer on the electrode surface.

4. The method according to claim 3, characterized in that, The clay material is composed of one or more raw materials selected from diatomite, kaolin, halloysite, montmorillonite, illite, vermiculite, sepiolite, diatomite, and palygorskite; Optionally, the powdered clay material is obtained by grinding raw clay material; Optionally, the grinding process is carried out by ball milling at a speed of 1000 rpm to 800 rpm for 1 hour to 8 hours; Optionally, the pressing process is carried out at a pressure of 1000 psi to 8000 psi; Optionally, the thickness of the sheet is 0.05mm-2mm; Optionally, the sintering temperature is 200℃-800℃; Optionally, the heating rate of the sintering process is 1-20°C / min; Optionally, the sintering process takes 2 to 10 hours. Optionally, the thickness of the solid-liquid interface layer is 0.05 mm to 1 mm.

5. A method for preparing a solid-liquid interface layer on an electrode surface, characterized in that, The process includes mixing powdered clay material with a binder to obtain a mixture, preparing the mixture into a slurry, and coating the slurry onto the electrode surface by spin coating to obtain a solid-liquid interface layer on the electrode surface.

6. The method according to claim 5, characterized in that, The clay material is composed of one or more raw materials selected from diatomite, kaolin, halloysite, montmorillonite, illite, vermiculite, sepiolite, diatomite, and palygorskite; Optionally, the powdered clay material is obtained by grinding raw clay material; Optionally, the grinding process is carried out by ball milling at a speed of 1000 rpm to 800 rpm for 1 hour to 8 hours; Optionally, the binder is methylcellulose, hydroxypropylcellulose, ethylcellulose, povidone, or copovidone; Optionally, the mass ratio of the powdered clay material to the binder is (9.5-7.5):(0.5-2.5); Optionally, the mixing process is carried out at a rotation speed of 1000 rpm to 5000 rpm; Optionally, the spin coating is performed in a benchtop spin coater with an output power of 60 watts and a suction cup diameter of 2-16 cm.

7. The application of the electrode surface solid-liquid interface layer according to claim 1 or 2, or the electrode surface solid-liquid interface layer obtained by the method according to any one of claims 3-6, in the preparation of battery electrodes.

8. The application according to claim 7, characterized in that, The battery is an aqueous battery.

9. The application according to claim 7, characterized in that, The electrode is a positive electrode material; Optionally, the positive electrode material is a manganese-based material or a vanadium-based material; Optionally, the manganese-based material is manganese dioxide, lithium manganate, or zinc manganate. Optionally, the vanadium-based material is vanadium pentoxide or sodium vanadate.

10. The application according to claim 7, characterized in that, The electrode is a negative electrode material; Optionally, the negative electrode material is a zinc-based material; Optionally, the zinc-based material is a negative electrode made of zinc foil, zinc powder, or a negative electrode material made of a zinc-containing alloy.

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