Micron-sized sno composite negative electrode material and preparation method

Abstract

The application relates to a preparation method of a micron SnO composite negative electrode material. The features include the following steps: (1) preparing a conductive carbon / tin salt mixed solution and an ammonia water precipitant solution; (2) adding the precipitant solution into the conductive carbon / tin salt mixed solution at a certain flow rate, and performing constant-temperature microwave reaction; (3) after the reaction is completed, the co-precipitate is filtered and washed to be neutral; (4) then, the co-precipitate is dried to obtain the micron SnO composite negative electrode material. The micron SnO composite negative electrode material prepared by the application has a discharge specific capacity of 900 mAh / g or more after 30 cycles, and has good cycle performance.

Description

Technical Field

[0001] This article belongs to the field of new energy materials technology, and relates to a micron-sized SnO composite anode material and its preparation method, specifically a micron-sized SnO composite anode material for lithium-ion batteries and its preparation method. Background Technology

[0002] Lithium-ion batteries possess advantages such as high energy density, long cycle life, low self-discharge rate, and environmental friendliness, making them crucial energy storage and conversion devices. Currently, commercially available lithium-ion battery anode materials primarily consist of graphite and artificial carbon materials. While carbon anode materials offer high cycle life, their specific capacity is low, failing to meet the requirements of high-energy-density lithium-ion power batteries. Improving both positive and negative electrode materials to further enhance their specific energy density and cycle performance is a key factor in meeting the needs of automotive lithium-ion power batteries. Tin oxide (SnO) is an important metal oxide. As a p-type semiconductor material, its direct optical bandgap of 2.5–3.4 eV has attracted significant attention, with wide applications in catalyst materials, photocatalytic materials, gas-sensitive materials, lithium-ion battery anode materials, solid-state fuel cell materials, and semiconductor device materials. As a lithium-ion battery anode material, its low cost, high theoretical specific capacity (875 mAh / g), and low charge / discharge plateau have garnered considerable interest from researchers.

[0003] In recent years, researchers have used various synthesis methods, including liquid phase deposition, hydrothermal methods, solvothermal methods, sol-gel methods, spray pyrolysis, and chemical vapor deposition, to prepare micro and nano SnO materials with different morphologies, such as particles, blocks, sheets, flowers, disks, and thin films. These different morphologies exhibit different electrochemical properties. Studies have shown that SnO has a high initial specific capacity during charge and discharge, but its capacity decays rapidly in subsequent cycles, and its cycle performance needs further improvement. The main reason for this cycle decay is firstly the formation of irreversible Li₂O during the initial charge and discharge process, resulting in a large irreversible capacity. Secondly, the volume effect during charge and discharge causes the material structure to collapse, affecting its cycle and rate performance. Maintaining the stability of morphology, structure, and composition is beneficial to the lithium storage cycle performance of tin-based oxides. Improving the structural stability of electrode materials by controlling the morphology, particle size, and composite composition is an important way to enhance the electrochemical performance of SnO materials. Summary of the Invention

[0004] To improve the lithium storage performance of SnO, this invention provides a method for directly preparing micron-sized SnO composite materials through microwave liquid-phase synthesis.

[0005] The technical solution involved in this invention is as follows: a micron-sized SnO composite anode material and its preparation method, characterized by comprising the following steps:

[0006] (1) Dissolve soluble tin salt in acid, wherein the molar ratio of tin salt to acid is 1:0.5~1.0, and then add deionized water to prepare Sn. 2+ A tin salt solution with a concentration of 0.1–0.5 mol / L; conductive carbon material is added to the tin salt solution prepared above, and after being fully ultrasonicated or stirred and dispersed, a conductive carbon / tin salt mixed solution is prepared, wherein the mass of the conductive carbon material is 2%–12% of the total mass of the SnO composite material.

[0007] (2) Measure concentrated ammonia (25%) into deionized water to prepare an ammonia solution as a precipitant, wherein the volume of concentrated ammonia accounts for 5-10% of the total volume of the solution;

[0008] (3) Place the prepared conductive carbon / tin salt mixed solution in a microwave reactor, microwave-assisted heating to 55-75°C, then add the above precipitant solution to the tin salt solution at 100-1000 mL / min, and magnetically stir for 0.1-5 minutes;

[0009] (4) After the microwave reaction is completed, the solid and liquid are separated, and then the precipitate is washed with deionized water until neutral. Then the precipitate is dried in a vacuum drying oven at 100-180°C for 2-12 hours to obtain a micron-sized SnO composite anode material as described in this invention.

[0010] The tin salt in step (1) is stannous chloride.

[0011] The acid in step (1) is concentrated hydrochloric acid (36% to 38%).

[0012] The conductive carbon material in step (1) is a type of carbon nanotube or carbon nanofiber.

[0013] The beneficial effects of the present invention are as follows: (1) The present invention uses soluble tin salt containing carbon materials to directly prepare micron-sized SnO composites by reacting with ammonia water precipitant in microwaves. The reaction time is short and the synthesis efficiency is high. (2) In the present invention, there is no need for hydrothermal or other operations after microwave precipitation reaction. The product does not need to be ground after drying and can be used directly, which reduces the operation steps, simplifies the process, and shortens the cycle. (3) The micron-sized SnO composite material obtained by the preparation method of the present invention is mainly in the form of sheet-like aggregates with a spherical morphology. Attached Figure Description

[0014] Figure 1 The image shows the XRD pattern of the SnO composite material prepared according to Example 1.

[0015] Figure 2The image shows a SEM image of the SnO composite material prepared according to Example 1.

[0016] Figure 3 The cycling performance of the SnO composite material prepared according to Example 1 is shown. Detailed Implementation

[0017] Examples of the present invention are as follows, but the invention is not limited thereto.

[0018] Example 1:

[0019] (1) Dissolve 0.03 mol of stannous chloride in 2 ml of concentrated hydrochloric acid (12 mol / L), with a molar ratio of 1:0.8, and then add deionized water to make up to 300 ml. The Sn in the solution 2+ The concentration is 0.1 mol / L; then carbon nanotubes are added to the above tin solution, and after thorough sonication, a carbon nanotube / tin salt mixed solution is prepared, wherein the mass of carbon nanotubes is 5% of the total mass of SnO composite material.

[0020] (2) Take 7 ml of concentrated ammonia (13.8 mol / L) and add it to deionized water, and make up to 100 ml to prepare a precipitant.

[0021] (3) Place the carbon nanotube / tin salt mixed solution in a microwave reactor, microwave-assisted heating to 60°C, then add the prepared precipitant solution to the tin salt solution at 400 mL / min, and magnetically stir for 3 minutes.

[0022] (4) After the microwave reaction is completed, the material is cooled and separated into solid and liquid phases. It is then washed with deionized water until neutral. The precipitate is then vacuum dried at 120°C for 6 hours to obtain the micron-sized SnO composite anode material described in this invention.

[0023] (5) The phase composition and morphology of the micron-sized SnO composite material prepared in this embodiment are as follows: Figure 1 and Figure 2 As shown, Figure 1 The crystal phase structure of the SnO composite material is shown. Figure 2 The SnO composite material shown is a spherical morphology with sheet-like aggregates, in which carbon nanotubes (CNTs) are clearly distributed between the SnO sheets; Figure 3 The cycling performance of the prepared micron-sized SnO composite material as a lithium-ion battery anode material is shown in the figure. Within the voltage range of 0.01V to 2.5V, the anode material has a high initial charge-discharge specific capacity at a current density of 100 mA / g, and the discharge specific capacity after 30 cycles is 916.5 mAh / g, indicating stable cycling performance.

[0024] Example 2:

[0025] (1) Dissolve 0.048 mol of stannous chloride in 4 ml of concentrated hydrochloric acid (12 mol / L), with a molar ratio of 1:1, and then add deionized water to make up to 96 ml. The Sn in the solution 2+ The concentration is 0.5 mol / L; then carbon nanofibers are added to the above tin solution, and after thorough stirring, a carbon nanofiber / tin salt mixed solution is prepared, wherein the mass of carbon nanofibers is 2% of the total mass of SnO composite material.

[0026] (2) Take 10 ml of concentrated ammonia (13.8 mol / L) and add it to deionized water, and make up to 100 ml to prepare a precipitant.

[0027] (3) Place the carbon nanofiber / tin salt mixed solution in a microwave reactor, microwave-assisted heating to 75°C, then add the above mixed precipitant solution to the tin salt solution at 2000 mL / min, and magnetically stir for 0.1 minutes.

[0028] (4) After the microwave reaction is completed, the material is cooled and separated into solid and liquid phases. It is then washed with deionized water until neutral. The precipitate is then vacuum dried at 180°C for 2 hours to obtain the micron-sized SnO composite anode material described in this invention.

[0029] Example 3:

[0030] (1) Dissolve 0.01 mol of stannous chloride in 0.42 ml of concentrated hydrochloric acid (12 mol / L), with a molar ratio of 1:0.5, and then add deionized water to bring the volume to 100 ml. The Sn in the solution... 2+ The concentration is 0.1 mol / L; then carbon nanotubes are added to the above tin solution, and after thorough sonication, a carbon nanotube / tin salt mixed solution is prepared, wherein the mass of carbon nanotubes is 12% of the total mass of SnO composite material.

[0031] (2) Take 5 ml of concentrated ammonia (13.8 mol / L) and add it to deionized water, and make up to 50 ml to prepare a precipitant.

[0032] (3) Place the carbon nanotube / tin salt mixed solution in a microwave reactor, microwave-assisted heating to 55°C, then add the above mixed precipitant solution to the tin salt solution at 100 mL / min, and magnetically stir the reaction for 5 minutes.

[0033] (4) After the microwave reaction is completed, the solid and liquid are separated, and then the precipitate is washed with deionized water until neutral. Then the precipitate is dried at 100°C for 12 hours to obtain a micron-sized SnO composite anode material of the present invention.

Claims

1. A method for preparing a micron-sized SnO composite anode material, characterized in that, Includes the following steps: (1) Dissolve soluble tin salt in acid, wherein the molar ratio of tin salt to acid is 1:0.5~1.0, and then add deionized water to prepare Sn. 2+ A tin salt solution with a concentration of 0.1–0.5 mol / L is prepared; conductive carbon material is added to the tin salt solution prepared above, and after thorough ultrasonic or stirring dispersion, a conductive carbon / tin salt mixed solution is prepared, wherein the mass of the conductive carbon material is 2%–12% of the total mass of the SnO composite material; (2) Measure out concentrated ammonia water and add deionized water to prepare an ammonia solution as a precipitant, wherein the volume of concentrated ammonia water accounts for 5-10% of the total volume of the solution; (3) Place the prepared conductive carbon / tin salt mixed solution in a microwave reactor, microwave-assisted heating to 55-75°C, then add the above precipitant solution to the tin salt solution at 100-1000 mL / min, and magnetically stir for 0.1-5 minutes; (4) After the microwave reaction is completed, the solid and liquid are separated, and then the precipitate is washed with deionized water until neutral. Then the precipitate is dried in a vacuum drying oven at 100-180°C for 2-12 hours to obtain the micron-sized SnO composite anode material.

2. The method for preparing a micron-sized SnO composite anode material as described in claim 1, characterized in that: The tin salt in step (1) is SnCl2·2H2O.

3. The method for preparing a micron-sized SnO composite anode material as described in claim 1, characterized in that: The acid in step (1) is concentrated hydrochloric acid.

4. The method for preparing a micron-sized SnO composite anode material as described in claim 1, characterized in that: The conductive carbon material in step (1) is a type of carbon nanotube or carbon nanofiber.

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