A preparation method of liquid metal composite electrode based on micro-oxidation scraping method and its application

Abstract

A preparation method and application of a liquid metal composite electrode based on a micro-oxidation scraping method, wherein Ga, Sn, and In metals are heated, stirred, and melted under atmosphere protection to obtain a gallium-based liquid metal alloy, and the alloy is placed on the surface of a modified carbon-based material; a synchronous micro-oxidation scraping method is used to allow the liquid metal to react chemically with the surface chemical functional groups of the modified carbon material, thereby spreading and wetting the surface of the carbon-based material; after multiple scrapings, liquid metal-carbon-based materials with different mass ratios are obtained. After rolling, the above-mentioned materials are further reacted at high temperature to enhance the interfacial chemical reaction between the micro-oxidation liquid metal and the surface of the modified carbon material; and the materials are cut or stamped into desired sizes. The liquid metal self-supporting electrode prepared by the synchronous micro-oxidation technology of the present invention can significantly improve the specific capacity of lithium / sodium ion liquid metal battery electrodes. Using this electrode in battery manufacturing will help to significantly improve the performance of liquid metal batteries in the future.

Description

Technical Field

[0001] The present invention belongs to the technical field of surface coating preparation, and in particular relates to a preparation method of a liquid metal composite electrode based on a micro-oxidation scraping method and an application thereof. Technical Background

[0002] Metals, with their excellent electrical conductivity and reactivity, naturally possess advantages as electrode active materials. Furthermore, room-temperature liquid metals, such as gallium, tin, and indium, leverage the inherent self-healing properties of liquid materials, enabling them to repair cracks during battery cycling, thereby addressing the problem of a sharp drop in battery capacity caused by microstructural damage in the electrode active materials after multiple cycles. Using flexible conductive materials as current collectors and loading electrochemically active materials onto their surfaces or internally is a primary approach to constructing self-supporting electrodes. Among the many flexible substrates, carbon-based flexible support materials, such as carbon fiber cloth, carbon paper, and carbon gel, offer excellent thermal and chemical stability, high conductivity, low cost, and industrial scalability, making them ideal for the fabrication of flexible, self-supporting electrodes. However, liquid metals exhibit significant surface tension, preventing them from wetting common materials, such as carbon materials and polymers. This prevents the liquid metal from interacting with the carbon-based flexible materials to form a composite material, making it difficult to form a stable, flexible, self-supporting electrode. This presents a significant challenge in the fabrication of liquid metal composites. To address the problem of liquid metal's high surface tension making it difficult to wet the base material, one current solution is to nano-process the active material, then evenly mix it with a conductive additive and binder and coat it on the current collector. This method has many disadvantages: First, the nano-processing of the active material is cumbersome, and it will cause the metal material to lose its original overall connectivity, making it impossible to fully utilize the self-healing properties of the liquid metal; second, for carbon-based materials used as flexible electrodes, they are prone to deformation and fracture after multiple bending, resulting in gaps between the active material and the base material, which sharply reduces the adhesion effect of the adhesive and easily causes the active material to fall off the base material, resulting in electrode failure. In recent years, some industrial preparation processes have chosen methods such as immersion in strong oxidizing solutions and plasma to modify the base material to improve adhesion problems, but the current modification methods each have their own disadvantages and cannot completely solve the problem of high surface tension of liquid metal. Therefore, how to modify the surface of liquid metal, form strong chemical bonds with carbon-based materials such as modified carbon fiber cloth using better modification methods, reduce the surface tension of liquid metal, enhance interfacial bonding, and solve the problem of liquid metal wetting is the focus of current research. Summary of the Invention

[0003] The purpose of the present invention is to provide a preparation method and application of a liquid metal composite electrode based on a micro-oxidation scraping method, using synchronous micro-oxidation brush coating technology to coat Ga-based liquid metal on the surface of a carbon-based material to obtain a flexible support electrode with self-healing properties.

[0004] To achieve the above object, the present invention provides a method for preparing the above electrode material, comprising the following steps:

[0005] 1) Under atmosphere protection conditions, 50-100 parts by mass of Ga, 0-30 parts by mass of Sn, and 0-30 parts by mass of In are liquefied by stirring to obtain a gallium-based liquid metal alloy;

[0006] 2) modifying the carbon-based material by calcining it at high temperature in a muffle furnace;

[0007] 3) The gallium-based room temperature liquid alloy obtained in step 1) was heated to 1-10 mg / cm at 25-80°C. 2 The loading amount is achieved by a simultaneous micro-oxidation blade coating method to allow the liquid metal to spread and wet on the surface of the carbon-based material;

[0008] 4) using a rolling device to roll the surface of the material obtained in step 3) at a rolling pressure of 7-17 MPa to make the liquid metal more evenly distributed on the surface of the carbon-based material;

[0009] 5) The rolled carbon-based material is further reacted at 100-200° C. for 10-12 hours;

[0010] 6) Take out the coated room temperature liquid metal-carbon-based material composite electrode and cut or stamp it into the required size.

[0011] The Ga, Sn and In are mixed in a mass ratio of Ga:In:Sn=68.5:21.5:10.

[0012] The selected carbon-based material is carbon fiber cloth.

[0013] The modification treatment in step 2) is to heat the carbon fiber cloth in a muffle furnace from room temperature at a heating rate of 5°C / min to 250-350°C and calcine for 1-4 hours.

[0014] The modified carbon fiber cloth is washed with deionized water until the pH is 7, and then dried to obtain a carbon fiber cloth having oxygen-containing functional groups such as -COOH and -OH on the surface.

[0015] The scraping tool used in the scraping method of step 3) is a flexible rubber plate, a dense foam plate, a cardboard or a scraper.

[0016] In the step 3), the scraping speed is 0.5-2 cm / s, the scraping pressure is 2-8 N, and the scraping is repeated 10-20 times.

[0017] The rolling speed of step 4) is 50 mm / s.

[0018] Application of the composite electrode prepared by the above method in lithium / sodium metal batteries.

[0019] The present invention modifies the carbon-based material so that oxygen-containing functional groups grow on its surface. By repeated scraping, the liquid metal continuously generates new interfaces, and the new interfaces continuously form new GaO under the action of air oxidation. X Elastic oxide layer. During the continuous oxidation process of liquid metal, the chemical reaction between its surface oxide layer and the surface of carbon-based material is realized synchronously. Through the oxygen vacancy-rich GaO X The continuous chemical bonding with the oxygen-containing functional groups on the surface of the carbon-based material realizes the spreading and wetting of the carbon-based material. The key point of the present invention is that the Ga-based liquid metal is spread by repeated scraping in an oxygen-containing environment, and the Ga-based liquid metal is oxidized while its oxygen vacancy-rich GaO X The physical adsorption force between the liquid metal and the carbon-based material is converted into GaO X The chemical bonding with the oxygen-containing functional groups on the surface of the carbon-based material enables the Ga-based liquid metal to be firmly adsorbed on the surface of the carbon-based material. The Ga-based liquid metal is coated on the surface of the carbon-based material using a simple synchronous micro-oxidation scraping technology to obtain a flexible self-supporting electrode with self-healing properties. The present invention solves the problem that liquid metal is difficult to wet on the surface of carbon-based materials and cannot be directly loaded for battery electrodes. The liquid metal self-supporting electrode prepared using synchronous micro-oxidation technology can significantly improve a series of indicators of lithium / sodium ion liquid metal battery electrodes. Using this electrode in battery manufacturing will help to significantly improve the performance of liquid metal batteries in the future. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of improved wettability of the surface modified according to Example 1 of the present invention.

[0021] Figure 2 Schematic diagram of the liquid metal synchronous micro-oxidation coating process in the preparation process of the present invention.

[0022] Figure 3 This is the negative electrode of the battery after loading prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0023] Example 1

[0024] 1) Under atmosphere protection conditions, Ga, In, and Sn are liquefied by stirring in a ratio of Ga:In:Sn=68.5:21.5:10 by mass to obtain a gallium-based liquid metal alloy;

[0025] 2) The carbon fiber cloth was heated in a muffle furnace from room temperature at a heating rate of 5°C / min to 300°C and calcined for 3 hours, washed with deionized water to a pH of 7, and then dried to obtain a carbon fiber cloth with oxygen-containing functional groups such as -COOH and -OH on the surface;

[0026] like Figure 2 As shown, 3) the gallium-based room temperature liquid alloy obtained in step 1) was heated to 5 mg / cm at 25°C. 2 The load is placed on the surface of the carbon fiber cloth obtained in step 2), and a flexible rubber plate is used to scrape at a speed of 1 cm / s and a scraping pressure of 5 N. Repeat the scraping 20 times to ensure that the liquid metal is evenly loaded on the surface of the carbon fiber cloth and between the carbon fiber gaps;

[0027] 4) rolling the surface of the material obtained in step 3) using a rolling device at a rolling speed of 50 mm / s, a rolling pressure of 8 MPa, and a rolling gap of 0.7 mm to make the liquid metal more evenly distributed on the surface of the carbon-based material;

[0028] 5) The rolled carbon-based material was kept at 100° C. for 12 hours for further reaction;

[0029] 6) Take out the coated room temperature liquid metal-carbon-based material composite electrode and cut or stamp it into the required size.

[0030] Depend on Figure 1 It can be seen that the wetting problem can be solved theoretically by adopting the micro-oxidation interface chemical action mechanism of the present invention.

[0031] Depend on Figure 3 It can be seen that a self-supporting electrode with good wetting properties can be prepared through the micro-oxidation process.

[0032] Example 2

[0033] 1) Under atmosphere protection conditions, Ga and Sn are mixed in a mass ratio of Ga:Sn=88:12 and liquefied by stirring to obtain a gallium-based liquid metal alloy;

[0034] 2) The carbon fiber cloth was heated in a muffle furnace from room temperature at a heating rate of 5°C / min to 250°C for 4 hours, washed with deionized water to a pH of 7, and then dried to obtain a carbon fiber cloth with oxygen-containing functional groups such as -COOH and -OH on the surface;

[0035] 3) The gallium-based room temperature liquid alloy obtained in step 1) was heated to 1 mg / cm at 50°C. 2 The load is placed on the surface of the carbon fiber cloth obtained in step 2), and a dense foam board is used to scrape at a speed of 1 cm / s and a scraping pressure of 5 N. Repeat the scraping 20 times to ensure that the liquid metal is evenly loaded on the surface of the carbon fiber cloth and between the carbon fiber gaps;

[0036] 4) rolling the surface of the material obtained in step 3) using a rolling device at a rolling speed of 50 mm / s, a rolling pressure of 8 MPa, and a rolling gap of 0.8 mm to make the liquid metal more evenly distributed on the surface of the carbon-based material;

[0037] 5) The rolled carbon-based material was further reacted at 200° C. for 10 hours;

[0038] 6) Take out the coated room temperature liquid metal-carbon-based material composite electrode and cut or stamp it into the required size.

[0039] Example 3

[0040] 1) Under atmosphere protection conditions, Ga, In, and Sn are mixed in a mass ratio of Ga:In:Sn=68.5:21.5:10 and liquefied by stirring to obtain a gallium-based liquid metal alloy;

[0041] 2) The carbon fiber cloth was heated in a muffle furnace from room temperature at a heating rate of 5°C / min to 350°C for 2 hours, washed with deionized water to a pH of 7, and then dried to obtain a carbon fiber cloth with oxygen-containing functional groups such as -COOH and -OH on the surface;

[0042] 3) The gallium-based room temperature liquid alloy obtained in step 1) was heated to 6 mg / cm at 50°C. 2 The load was placed on the surface of the carbon fiber cloth obtained in step 2), and cardboard was used to scrape at a speed of 1 cm / s and a pressure of 4 N. The scraping was repeated 20 times to ensure that the liquid metal was evenly loaded on the surface of the carbon fiber cloth and between the carbon fiber gaps;

[0043] 4) rolling the surface of the material obtained in step 3) using a rolling device at a rolling speed of 50 mm / s, a rolling pressure of 10 MPa, and a rolling gap of 0.7 mm to make the liquid metal more evenly distributed on the surface of the carbon-based material;

[0044] 5) The rolled carbon-based material was kept at 100° C. for 12 hours for further reaction;

[0045] 6) Take out the coated room temperature liquid metal-carbon-based material composite electrode and cut or stamp it into the required size.

[0046] Example 4

[0047] 1) Under atmosphere protection conditions, Ga, In, and Sn are mixed in a mass ratio of Ga:In:Sn=68.5:21.5:10 and liquefied by stirring to obtain a gallium-based liquid metal alloy;

[0048] 2) The carbon fiber cloth was heated in a muffle furnace from room temperature at a heating rate of 5°C / min to 300°C and calcined for 3 hours, washed with deionized water to a pH of 7, and then dried to obtain a carbon fiber cloth with oxygen-containing functional groups such as -COOH and -OH on the surface;

[0049] 3) The gallium-based room temperature liquid alloy obtained in step 1) was heated to 5 mg / cm at 80°C. 2 The load is placed on the surface of the carbon fiber cloth obtained in step 2), and a scraper is used to scrape at a speed of 1 cm / s and a pressure of 4 N. Repeat the scraping 20 times to ensure that the liquid metal is evenly loaded on the surface of the carbon fiber cloth and between the carbon fiber gaps;

[0050] 4) rolling the surface of the material obtained in step 3) using a rolling device at a rolling speed of 50 mm / s, a rolling pressure of 8 MPa, and a rolling gap of 0.6 mm to make the liquid metal more evenly distributed on the surface of the carbon-based material;

[0051] 5) The rolled carbon-based material was kept at 100° C. for 12 hours for further reaction;

[0052] 6) Take out the coated room temperature liquid metal-carbon-based material composite electrode and cut or stamp it into the required size.

[0053] Example 5

[0054] 1) Under atmosphere protection conditions, Ga and In are liquefied by stirring in a mass fraction ratio of Ga:In=78.2:21.8 to obtain a gallium-based liquid metal alloy;

[0055] 2) The carbon fiber cloth was heated in a muffle furnace from room temperature at a heating rate of 5°C / min to 300°C and calcined for 3 hours, washed with deionized water to a pH of 7, and then dried to obtain a carbon fiber cloth with oxygen-containing functional groups such as -COOH and -OH on the surface;

[0056] 3) The gallium-based room temperature liquid alloy obtained in step 1) was heated to 5 mg / cm at 25°C. 2 The load is placed on the surface of the carbon fiber cloth obtained in step 2), and a flexible rubber plate is used to scrape at a speed of 0.5 cm / s and a scraping pressure of 2 N. Repeat the scraping 20 times to ensure that the liquid metal is evenly loaded on the surface of the carbon fiber cloth and between the carbon fiber gaps;

[0057] 4) rolling the surface of the material obtained in step 3) using a rolling device at a rolling speed of 50 mm / s, a rolling pressure of 7 MPa, and a rolling gap of 0.7 mm to make the liquid metal more evenly distributed on the surface of the carbon-based material;

[0058] 5) The rolled carbon-based material was heated at 150° C. for 10 hours for further reaction;

[0059] 6) Take out the coated room temperature liquid metal-carbon-based material composite electrode and cut or stamp it into the required size.

[0060] Table 1

[0061]

[0062] Example 6

[0063] 1) Under the condition of atmosphere protection, 100 parts of Ga are taken and liquefied by stirring to obtain a gallium-based liquid metal alloy;

[0064] 2) The carbon fiber cloth was heated in a muffle furnace from room temperature at a heating rate of 5°C / min to 350°C for 1 hour, washed with deionized water to a pH of 7, and then dried to obtain a carbon fiber cloth with -COOH oxygen-containing functional groups on the surface;

[0065] 3) At 60°C, the gallium-based room temperature liquid alloy obtained in step 1) was heated to 10 mg / cm 2 The load is placed on the surface of the carbon fiber cloth obtained in step 2), and a flexible rubber plate is used to scrape at a speed of 2 cm / s and a scraping pressure of 8 N. Repeat the scraping 10 times to ensure that the liquid metal is evenly loaded on the surface of the carbon fiber cloth and between the carbon fiber gaps;

[0066] 4) rolling the surface of the material obtained in step 3) using a rolling device at a rolling speed of 50 mm / s, a rolling pressure of 17 MPa, and a rolling gap of 0.7 mm to make the liquid metal more evenly distributed on the surface of the carbon-based material;

[0067] 5) The rolled carbon-based material was heated at 180° C. for 11 hours for further reaction;

[0068] 6) Take out the coated room temperature liquid metal-carbon-based material composite electrode and cut or stamp it into the required size.

Claims

1. A method for preparing a liquid metal composite electrode based on a micro-oxidation blade coating method, characterized in that: The following steps are involved: 1) Under atmosphere protection conditions, 50-100 parts by mass of Ga, 0-30 parts by mass of Sn, and 0-30 parts by mass of In are liquefied by stirring to obtain a gallium-based liquid metal alloy; 2) The modification treatment is to heat the carbon fiber cloth in a muffle furnace from room temperature at a heating rate of 5°C / min to 250-350°C for 1-4h, and then wash the modified carbon fiber cloth with deionized water to pH = 7, and then dry it to obtain a carbon fiber cloth with -COOH and -OH oxygen-containing functional groups on the surface; 3) At 25-80°C, the gallium-based room temperature liquid alloy obtained in step 1) was heated to 1-10 mg / cm 2 The loading amount is achieved by a simultaneous micro-oxidation blade coating method to allow the liquid metal to spread and wet on the surface of the carbon-based material; 4) using a rolling device to roll the surface of the material obtained in step 3) at a rolling pressure of 7-17 MPa to make the liquid metal more evenly distributed on the surface of the carbon-based material; 5) The rolled carbon-based material is kept at 100-200°C for 10-12 hours for further reaction; 6) Take out the coated room temperature liquid metal-carbon-based material composite electrode and cut or stamp it into the required size.

2. The method for preparing a liquid metal composite electrode based on a micro-oxidation blade coating method according to claim 1, characterized in that: The Ga, Sn and In are mixed in a mass ratio of Ga:In:Sn=68.5:21.5:

10.

3. The method for preparing a liquid metal composite electrode based on a micro-oxidation blade coating method according to claim 1, characterized in that: The scraping tool used in the scraping method of step 3) is a flexible rubber plate, a dense foam plate, a cardboard or a scraper.

4. The method for preparing a liquid metal composite electrode based on a micro-oxidation blade coating method according to claim 1, characterized in that: In the step 3), the scraping speed is 0.5-2 cm / s, the scraping pressure is 2-8 N, and the scraping is repeated 10-20 times.

5. The method for preparing a liquid metal composite electrode based on a micro-oxidation blade coating method according to claim 1, characterized in that: The rolling speed of step 4) is 50 mm / s.

6. Use of a composite electrode prepared by the method according to any one of claims 1 to 5 in a lithium / sodium metal battery.

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