Method for improving performance of rechargeable battery sn@mxene composite negative electrode material

Abstract

The application provides a method for improving the performance of a rechargeable battery Sn@MXene composite negative electrode material, which comprises the following steps: S1), adding MXene into a solvent and performing ultrasonic treatment for 30-60 minutes; S2), adding a chelating agent and a reducing agent into the solution after the ultrasonic treatment and stirring for 1h; S3), adding a tin source at a speed of 1ml / min-4.5ml / min by using a syringe, and continuing to stir for 1h after the dropwise addition is completed; S4), performing centrifugation by using a centrifugal solvent, and then drying in a vacuum drying box at 80 DEG C for 12h; and S5), placing the dried material into a high-temperature environment for a period of time and then quickly transferring the material into an air environment. The application enhances the adhesion of tin on the surface of MXene by reducing the contact angle of tin on the surface of titanium carbide MXene, and improves the performance of the Sn@MXene composite negative electrode material.

Description

Technical Field

[0001] This invention relates to the field of battery anode material technology, and in particular to a method for improving the performance of Sn@MXene composite anode materials for rechargeable batteries. Background Technology

[0002] Lithium-ion batteries have advantages such as high energy density, high operating voltage, long cycle life, and low environmental pollution. Their application as energy storage devices is becoming increasingly widespread, from small items like mobile phones, laptops, and miniature cameras to large items like electric vehicles, uninterruptible power supplies, and solar power systems. They also have a further trend of replacing traditional nickel-cadmium and lead-acid batteries as power and energy storage sources, and have become a new type of green high-energy chemical power source with great development potential in the world today.

[0003] Lithium-ion anodes, as a crucial component of batteries, have always attracted widespread attention. Traditional lithium-ion batteries use graphite as the anode, which, while offering advantages in cycle performance, has a theoretical specific capacity of only 372 mAh / g, insufficient to meet the high energy density requirements of applications such as electric vehicles. Furthermore, graphite is prone to lithium deposition under high current, posing certain safety concerns. Tin materials, due to their large theoretical specific capacity (reaching up to 993 mAh / g, and a volumetric specific capacity as high as 7313 mAh / cm³), abundant reserves, and good conductivity, have become a key focus of research on lithium-ion battery anode materials.

[0004] However, tin electrode materials exhibit a huge volume expansion effect (>260%) during repeated charge and discharge cycles, causing the electrode material to pulverize and easily peel off from the conductive network, ultimately leading to a rapid decrease in battery capacity and limiting its commercial development.

[0005] Existing technologies refine the particle size of tin-based materials to obtain nanoscale materials. Nanoscale tin materials possess unique surface and size effects, which can reduce stress generated during cycling and mitigate volume changes during lithium insertion / extraction processes. The nanostructure also shortens the lithium-ion transport distance, improving rate performance. However, due to the small size of tin nanoparticles, they are prone to agglomeration, leading to capacity decay.

[0006] Secondly, existing technologies utilize composite materials made with carbon materials. Carbon materials can mitigate the volume expansion and particle aggregation of tin materials during charging and discharging, but tin is prone to detaching from the surface of carbon materials, resulting in irreversible capacity buildup. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a method for improving the performance of Sn@MXene composite anode materials for rechargeable batteries. This invention enhances the adhesion of tin to the MXene surface by reducing the contact angle of tin on the titanium carbide MXene surface, thereby improving the performance of the Sn@MXene composite anode material.

[0008] The technical solution of this invention is: a method for improving the performance of Sn@MXene composite anode material for rechargeable batteries, comprising the following steps:

[0009] S1) Add MXene to the solvent and sonicate for 30-60 minutes;

[0010] S2) Add chelating agent and reducing agent to the sonicated solution and stir for one hour;

[0011] S3) Add the tin source using a syringe at a rate of 0.1 ml / min to 4.5 ml / min. After the addition is complete, continue stirring for 1 hour.

[0012] S4) Centrifuge using a centrifugal solvent, then dry in a vacuum drying oven at 80°C for 12 hours;

[0013] S5) Place the dried material in a high temperature environment for a period of time and then quickly transfer it to the air environment.

[0014] Preferably, in step S1), the MXene is one of Ti3C2 and Ti2C.

[0015] Preferably, in step S1), the solvent is one of ethylene glycol, ethanol, or deionized water.

[0016] Preferably, in step S2), the chelating agent is one of polyvinylpyrrolidone (PVP), polyacrylonitrile (PAN), polyvinyl alcohol (PVA), citric acid, and ethylenediaminetetraacetic acid (EDTA).

[0017] Preferably, in step S2), the reducing agent is potassium borohydride or sodium borohydride.

[0018] Preferably, in step S3), the tin source is one of SnCl4, stannous 2-ethylhexanoate, and SnCl2.

[0019] Preferably, in step S3), the mass ratio of the chelating agent to the tin source is 0.05 to 0.5:1.

[0020] Preferably, in step S3), the mass ratio of the chelating agent to the tin source is 0.1:1.

[0021] Preferably, in step S3), the mass ratio of the reducing agent to the tin source is 1 to 100:1.

[0022] Preferably, in step S3), the mass ratio of the reducing agent to the tin source is 3.3:1.

[0023] Preferably, in step S3), the tin source is added at a rate of 1 ml / min.

[0024] Preferably, in step S3), the mass ratio of the tin source to MXene is 1 to 100:1.

[0025] Preferably, in step S3), the mass ratio of the tin source to MXene is 10:1.

[0026] Preferably, the centrifugal solvent in step S4) is deionized water and ethanol or methanol. If the solvent in step S1) is ethylene glycol, then the centrifugal solvent must be methanol.

[0027] Preferably, the high temperature mentioned in step S5) is 200 degrees to 1200 degrees.

[0028] The beneficial effects of this invention are as follows:

[0029] 1. This invention transforms the physical adsorption force between Sn and MXene into a chemical bonding force, improves the contact state between tin and MXene, reduces the contact angle of tin on the carbon surface, and solves the problem of tin easily falling off during charging and discharging, thus achieving the goal of stable cycling of tin composite material as battery negative electrode.

[0030] 2. This invention grows tin nanoparticles directly on the MXene surface in situ using a liquid-phase reduction method, and then reduces the contact angle of Sn on the MXene surface by high-temperature sintering and rapid cooling.

[0031] 3. This invention enhances the adhesion of tin to the MXene surface by reducing the contact angle of tin on the titanium carbide MXene surface, thereby improving the performance of the Sn@MXene composite anode material. Attached Figure Description

[0032] Figure 1 This is a cycle curve of a half-cell made by combining the Sn@MXene material of this invention with lithium foil.

[0033] Figure 2 This is a schematic diagram illustrating the principle of contact angle reduction in this invention. Detailed Implementation

[0034] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings:

[0035] Example 1

[0036] This embodiment provides a method for preparing Sn@Ti3C2 material, including the following steps:

[0037] S1) Add 0.1g Ti3C2 to 15mL ethylene glycol (DEG) solution and sonicate for 30 minutes;

[0038] S2) Add 0.01g PVP and 0.25g sodium borohydride to the sonicated solution and stir for 1 hour;

[0039] S3) Add 0.25 mL of stannous 2-ethylhexanoate using a syringe at a rate of 4.5 mL / min. After the addition is complete, continue stirring for 1 hour.

[0040] S4) Centrifuge with methanol solution, then dry in a vacuum drying oven at 80°C for 12 hours;

[0041] S5) Place the dried material in a muffle furnace at 300°C for 5 minutes and then quickly transfer it to the air environment.

[0042] This invention utilizes Sn@Ti3C2 material combined with lithium foil to fabricate a half-cell, from Figure 1 As can be seen, the battery has a discharge specific capacity of 1363 mAh / g and a charge specific capacity of 814 mAh / g at a current density of 200 mA / g, with an initial coulombic efficiency of 59.7%. The discharge specific capacities for the 2nd, 10th, 100th, and 500th cycles are 857, 840, 756, and 713 mAh / g, respectively, demonstrating its excellent cycle performance.

[0043] A schematic diagram illustrating the principle of contact angle reduction in this invention can be found here. Figure 2 As shown in the figure, tin can maintain a low contact angle on the surface of titanium carbide material. Reducing the contact angle of tin on the surface of titanium carbide MXene (Ti3C2, Ti2C) can improve the contact state between tin and MXene, thereby fundamentally solving the problem of tin falling off due to volume expansion, and giving the battery the advantages of high capacity and high cycle life.

[0044] Example 2

[0045] This embodiment provides a method for preparing Sn@Ti3C2 material, including the following steps:

[0046] S1) Add 0.1g Ti3C2 to 15mL ethylene glycol (DEG) solution and sonicate for 40 minutes;

[0047] S2) Add 0.15g PVP and 0.25g sodium borohydride to the sonicated solution and stir for 1 hour;

[0048] S3) Add 2.5 mL of stannous 2-ethylhexanoate using a syringe at a rate of 1 mL / min. After the addition is complete, continue stirring for 1 hour.

[0049] S4) Centrifuge with methanol solution, then dry in a vacuum drying oven at 80°C for 12 hours;

[0050] S5) Place the dried material in a muffle furnace at 300°C for 5 minutes and then quickly transfer it to the air environment.

[0051] Example 3

[0052] This embodiment provides a method for preparing Sn@Ti3C2 material, including the following steps:

[0053] S1) Add 0.1g Ti3C2 to 15mL ethylene glycol (DEG) solution and sonicate for 60 minutes;

[0054] S2) Add 0.1g PVP and 0.25g sodium borohydride to the sonicated solution and stir for 1 hour;

[0055] S3) Add 2.5 mL of stannous 2-ethylhexanoate using a syringe at a rate of 3 mL / min. After the addition is complete, continue stirring for 1 hour.

[0056] S4) Centrifuge with methanol solution, then dry in a vacuum drying oven at 80°C for 12 hours;

[0057] S5) Place the dried material in a 300-degree high-temperature environment for a period of time, and then quickly transfer it to the air environment.

[0058] Example 4

[0059] This embodiment provides a method for preparing Sn@Ti2C material, including the following steps:

[0060] S1) Add 0.1g Ti2C to 15mL ethylene glycol (DEG) solution and sonicate for 30 minutes;

[0061] S2) Add 0.1g PVP and 0.25g sodium borohydride to the sonicated solution and stir for 1 hour;

[0062] S3) Add 2.5 mL of stannous 2-ethylhexanoate using a syringe at a rate of 1 mL / min. After the addition is complete, continue stirring for 1 hour.

[0063] S4) Centrifuge with methanol solution, then dry in a vacuum drying oven at 80°C for 12 hours;

[0064] S5) Place the dried material in a 300-degree high-temperature environment for a period of time, and then quickly transfer it to the air environment.

[0065] Example 5

[0066] This embodiment provides a method for preparing Sn@Ti2C material, including the following steps:

[0067] S1) Add 0.1g Ti2C to 15mL ethylene glycol (DEG) solution and sonicate for 60 minutes;

[0068] S2) Add 0.15g PVP and 2.5g sodium borohydride to the sonicated solution and stir for 1 hour;

[0069] S3) Add 2.5 mL of stannous 2-ethylhexanoate using a syringe at a rate of 4.5 mL / min. After the addition is complete, continue stirring for 1 hour.

[0070] S4) Centrifuge with methanol solution, then dry in a vacuum drying oven at 80°C for 12 hours;

[0071] S5) Place the dried material in a 300-degree high-temperature environment for a period of time, and then quickly transfer it to the air environment.

[0072] Example 6

[0073] This embodiment provides a method for preparing Sn@Ti2C material, including the following steps:

[0074] S1) Add 0.1g Ti2C to 15mL ethylene glycol (DEG) solution and sonicate for 60 minutes;

[0075] S2) Add 0.1g PVP and 2.5g sodium borohydride to the sonicated solution and stir for 1 hour;

[0076] S3) Add 2.5 mL of stannous 2-ethylhexanoate using a syringe at a rate of 2.5 mL / min. After the addition is complete, continue stirring for 1 hour.

[0077] S4) Centrifuge with methanol solution, then dry in a vacuum drying oven at 80°C for 12 hours;

[0078] S5) Place the dried material in a 300-degree high-temperature environment for a period of time, and then quickly transfer it to the air environment.

[0079] Example 7

[0080] This embodiment provides a method for preparing Sn@Ti2C material, including the following steps:

[0081] S1) Add 0.1g Ti2C to 15mL ethylene glycol (DEG) solution and sonicate for 60 minutes;

[0082] S2) Add 0.1g PAN and 0.25g potassium borohydride to the sonicated solution and stir for 1 hour;

[0083] S3) Add 2.5 mL of stannous 2-ethylhexanoate using a syringe at a rate of 2.5 mL / min. After the addition is complete, continue stirring for 1 hour.

[0084] S4) Centrifuge with methanol solution, then dry in a vacuum drying oven at 80°C for 12 hours;

[0085] S5) Place the dried material in a 300-degree high-temperature environment for a period of time, and then quickly transfer it to the air environment.

[0086] Example 8

[0087] This embodiment provides a method for preparing Sn@Ti2C material, including the following steps:

[0088] S1) Add 0.1g Ti2C to 15mL ethylene glycol (DEG) solution and sonicate for 60 minutes;

[0089] S2) Add 0.15g PAN and 0.3g potassium borohydride to the sonicated solution and stir for 1 hour;

[0090] S3) Add 2.5 mL of stannous 2-ethylhexanoate using a syringe at a rate of 2.5 mL / min. After the addition is complete, continue stirring for 1 hour.

[0091] S4) Centrifuge with methanol solution, then dry in a vacuum drying oven at 80°C for 12 hours;

[0092] S5) Place the dried material in a 300-degree high-temperature environment for a period of time, and then quickly transfer it to the air environment.

[0093] Example 9

[0094] This embodiment provides a method for preparing Sn@Ti2C material, including the following steps:

[0095] S1) Add 0.1g Ti2C to 15mL ethylene glycol (DEG) solution and sonicate for 30 minutes;

[0096] S2) Add 0.1g PAN and 0.3g potassium borohydride to the sonicated solution and stir for 1 hour;

[0097] S3) Add 2.5 mL of stannous 2-ethylhexanoate using a syringe at a rate of 1 mL / min. After the addition is complete, continue stirring for 1 hour.

[0098] S4) Centrifuge with methanol solution, then dry in a vacuum drying oven at 80°C for 12 hours;

[0099] S5) Place the dried material in a 300-degree high-temperature environment for a period of time, and then quickly transfer it to the air environment.

[0100] The embodiments and descriptions above are merely illustrative of the principles and preferred embodiments of the present invention. Various changes and modifications may be made to the present invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed.

Claims

1. A method for improving the performance of Sn@MXene composite anode materials for rechargeable batteries, characterized in that, Includes the following steps: S1) Add MXene to the solvent ethylene glycol and sonicate for 30-60 min; S2) Add chelating agent and reducing agent to the sonicated solution and stir for 1 hour; S3) Add the tin source using a syringe at a rate of 0.1 ml / min to 4.5 ml / min. After the addition is complete, continue stirring for 1 hour. S4) Centrifuge using a centrifugal solvent, then dry in a vacuum drying oven at 80°C for 12 hours; the centrifugal solvent is methanol; S5) Keep the dried material in a high-temperature environment for a period of time and then quickly transfer it to the air environment; the high temperature is 300°C and the holding time is 5 minutes. In step S1), the solvent is ethylene glycol; In step S2), the chelating agent is polyvinylpyrrolidone (PVP).

2. The method for improving the performance of Sn@MXene composite anode material for rechargeable batteries according to claim 1, characterized in that: In step S1), the MXene is one of Ti3C2 and Ti2C.

3. The method for improving the performance of Sn@MXene composite anode material for rechargeable batteries according to claim 1, characterized in that: In step S2), the reducing agent is potassium borohydride or sodium borohydride.

4. The method for improving the performance of Sn@MXene composite anode material for rechargeable batteries according to claim 1, characterized in that: In step S3), the tin source is one of SnCl4, stannous 2-ethylhexanoate, and SnCl2.

5. The method for improving the performance of Sn@MXene composite anode material for rechargeable batteries according to claim 1, characterized in that: In step S3), the mass ratio of the chelating agent to the tin source is 0.01 to 10:1; the mass ratio of the reducing agent to the tin source is 1 to 100:1; and the mass ratio of the tin source to MXene is 0.1 to 100:

1.

6. The method for improving the performance of Sn@MXene composite anode material for rechargeable batteries according to claim 1, characterized in that: In step S3), the tin source is added at a rate of 1 ml / min.

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