A fiber electrode and a method of manufacturing the same

Abstract

This invention relates to the field of carbon-based anode materials for lithium-ion batteries, specifically disclosing a carbon-based fiber electrode and its preparation method. The method involves ion implantation of Ir into the surface of graphite felt fiber material. Metallic Ir not only improves the electrochemical activity of the carbon-based electrode but also serves as a catalyst for the subsequent ALD (Alternating Discharge) process to prepare carbon nanotubes. Studies have shown that an appropriate amount of metallic Ir can improve the low-temperature capacity achievement rate of the battery when the fiber electrode is used as an anode; however, excessive Ir has negative effects. Therefore, the amount of metallic Ir implanted needs to be controlled at 1.2 × 10⁻⁶. 4 ions / cm 2 -7.2×10 8 ions / cm 2 Furthermore, when Ir and Ru are injected together, even better experimental results can be obtained, with a low-temperature battery capacity achievement rate exceeding 95%, which is suitable for the battery usage requirements of new energy vehicles.

Description

Technical Field

[0001] This invention relates to the field of carbon-based anode materials (H01M4 / 1393) for lithium-ion batteries, and specifically to a carbon-based fiber electrode and its preparation method. Background Technology

[0002] New energy vehicles are one of the hottest topics in the automotive industry today, representing a future trend towards cleaner and more sustainable transportation. As a crucial component of new energy vehicles, the decline in lithium battery activity at low temperatures is a key technical challenge, directly impacting the winter range and charging performance of electric vehicles. Therefore, this invention aims to improve the low-temperature activity of lithium batteries by focusing on electrode materials, thereby improving battery capacity achievement under low-temperature conditions. Summary of the Invention

[0003] The purpose of this invention is to provide a method for preparing a carbon-based fiber electrode, which can obtain a carbon-based fiber electrode with excellent low-temperature activity.

[0004] The technical solution of the present invention is as follows:

[0005] A method for preparing a carbon-based fiber electrode includes the following steps:

[0006] Pretreatment: Soak the graphite felt fiber material in anhydrous ethanol for 12-15 hours to obtain the degreased graphite felt fiber material. Then, use deionized water and ultrasonic cleaning several times until there is no ethanol residue. Finally, let the graphite felt fiber material stand and air dry to obtain the pretreated graphite felt fiber material.

[0007] Ion implantation (Ir): The pretreated graphite felt fiber material is placed in a metal vapor vacuum arc ion implantation device, and metallic Ir is selected for ion implantation. The ion voltage is 60-75 keV, and the Ir metal ion implantation amount is 1.2 × 10⁻⁶. 4 ions / cm 2 -7.2×10 8 ions / cm 2 ;

[0008] Carbon nanotubes are prepared by ALD method: Graphite felt fiber material is placed in an atomic layer deposition (ALD) apparatus and ethylene is introduced. Carbon atoms in the ethylene spontaneously accumulate on the surface of metal Ir through plasma discharge to form a carbon nanotube structure. The plasma discharge power is 55-60W, the discharge time of a single cycle is 1.5-2.0s, and the ethylene flow rate is 75-90sccm. Each cycle includes purging the residual gas in the ALD apparatus with inert gas. Finally, a carbon-based fiber electrode containing Ir and carbon nanotubes is obtained.

[0009] Preferably, the soaking time is 12 hours.

[0010] Preferably, the ion voltage is 60 keV.

[0011] Preferably, the plasma discharge power is 55W.

[0012] Preferably, the ethylene flow rate is 75 sccm.

[0013] Preferably, the discharge time of a single cycle is 1.5s.

[0014] Preferably, in the ion implantation step, 1.2 × 10⁻⁶ ions are also implanted. 6 ions / cm 2 -7.2×10 8 ions / cm 2 The metal Ru.

[0015] Furthermore, the present invention also provides a carbon-based fiber electrode, which is prepared by the above method.

[0016] This invention introduces Ir into the surface of graphite felt fiber materials via ion implantation. Metallic Ir not only improves the electrochemical activity of carbon-based electrodes but also serves as a catalyst for the subsequent ALD (Alternating Discharge) process to prepare carbon nanotubes. Studies have shown that an appropriate amount of metallic Ir can improve the low-temperature capacity achievement rate of batteries when the fiber electrode is used as the negative electrode; however, excessive Ir has negative effects. Therefore, the amount of metallic Ir implanted needs to be controlled at 1.2 × 10⁻⁶. 4 ions / cm 2 -7.2×10 8 ions / cm 2 Furthermore, when Ir and Ru are injected together, even better experimental results can be obtained, with a low-temperature battery capacity achievement rate exceeding 95%, which is suitable for the battery usage requirements of new energy vehicles. Detailed Implementation

[0017] The technical effects of the present invention will be verified through specific embodiments below, but the implementation of the present invention is not limited thereto.

[0018] Example 1

[0019] Pretreatment: The graphite felt fiber material was soaked in anhydrous ethanol for 12 hours to obtain the degreased graphite felt fiber material. Then, it was cleaned several times with deionized water and ultrasonic cleaning until there was no ethanol residue. The graphite felt fiber material was then left to stand and air dry to obtain the pretreated graphite felt fiber material.

[0020] Ion implantation (Ir): The pretreated graphite felt fiber material was placed in a metal vapor vacuum arc ion implantation device, and Ir metal was selected for ion implantation. The ion voltage was 60 keV, and the Ir metal ion implantation amount was 1.2 × 10⁻⁶. 4 ions / cm 2 ;

[0021] Carbon nanotubes are prepared by ALD method: Graphite felt fiber material is placed in an atomic layer deposition (ALD) apparatus and ethylene is introduced. Carbon atoms in the ethylene spontaneously accumulate on the surface of metal Ir through plasma discharge to form a carbon nanotube structure. The plasma discharge power is 55W, the discharge time of a single cycle is 1.5s, the ethylene flow rate is 75sccm, and each cycle includes purging the residual gas in the ALD apparatus with inert gas. Finally, a carbon-based fiber electrode containing Ir and carbon nanotubes is obtained.

[0022] Example 2

[0023] Pretreatment: The graphite felt fiber material was soaked in anhydrous ethanol for 12 hours to obtain the degreased graphite felt fiber material. Then, it was cleaned several times with deionized water and ultrasonic cleaning until there was no ethanol residue. The graphite felt fiber material was then left to stand and air dry to obtain the pretreated graphite felt fiber material.

[0024] Ion implantation (Ir): The pretreated graphite felt fiber material was placed in a metal vapor vacuum arc ion implantation device, and Ir metal was selected for ion implantation. The ion voltage was 60 keV, and the Ir metal ion implantation amount was 2.5 × 10⁻⁶. 5 ions / cm 2 ;

[0025] Carbon nanotubes are prepared by ALD method: Graphite felt fiber material is placed in an atomic layer deposition (ALD) apparatus and ethylene is introduced. Carbon atoms in the ethylene spontaneously accumulate on the surface of metal Ir through plasma discharge to form a carbon nanotube structure. The plasma discharge power is 55W, the discharge time of a single cycle is 1.5s, the ethylene flow rate is 75sccm, and each cycle includes purging the residual gas in the ALD apparatus with inert gas. Finally, a carbon-based fiber electrode containing Ir and carbon nanotubes is obtained.

[0026] Example 3

[0027] Pretreatment: The graphite felt fiber material was soaked in anhydrous ethanol for 12 hours to obtain the degreased graphite felt fiber material. Then, it was cleaned several times with deionized water and ultrasonic cleaning until there was no ethanol residue. The graphite felt fiber material was then left to stand and air dry to obtain the pretreated graphite felt fiber material.

[0028] Ion implantation (Ir): The pretreated graphite felt fiber material was placed in a metal vapor vacuum arc ion implantation device, and Ir metal was selected for ion implantation. The ion voltage was 60 keV, and the Ir metal ion implantation amount was 4.8 × 10⁻⁶. 7 ions / cm 2 ;

[0029] Carbon nanotubes are prepared by ALD method: Graphite felt fiber material is placed in an atomic layer deposition (ALD) apparatus and ethylene is introduced. Carbon atoms in the ethylene spontaneously accumulate on the surface of metal Ir through plasma discharge to form a carbon nanotube structure. The plasma discharge power is 55W, the discharge time of a single cycle is 1.5s, the ethylene flow rate is 75sccm, and each cycle includes purging the residual gas in the ALD apparatus with inert gas. Finally, a carbon-based fiber electrode containing Ir and carbon nanotubes is obtained.

[0030] Example 4

[0031] Pretreatment: The graphite felt fiber material was soaked in anhydrous ethanol for 12 hours to obtain the degreased graphite felt fiber material. Then, it was cleaned several times with deionized water and ultrasonic cleaning until there was no ethanol residue. The graphite felt fiber material was then left to stand and air dry to obtain the pretreated graphite felt fiber material.

[0032] Ion implantation (Ir): The pretreated graphite felt fiber material was placed in a metal vapor vacuum arc ion implantation device, and Ir metal was selected for ion implantation. The ion voltage was 60 keV, and the Ir metal ion implantation amount was 7.2 × 10⁻⁶. 8 ions / cm 2 ;

[0033] Carbon nanotubes are prepared by ALD method: Graphite felt fiber material is placed in an atomic layer deposition (ALD) apparatus and ethylene is introduced. Carbon atoms in the ethylene spontaneously accumulate on the surface of metal Ir through plasma discharge to form a carbon nanotube structure. The plasma discharge power is 55W, the discharge time of a single cycle is 1.5s, the ethylene flow rate is 75sccm, and each cycle includes purging the residual gas in the ALD apparatus with inert gas. Finally, a carbon-based fiber electrode containing Ir and carbon nanotubes is obtained.

[0034] Example 5

[0035] Pretreatment: The graphite felt fiber material was soaked in anhydrous ethanol for 12 hours to obtain the degreased graphite felt fiber material. Then, it was cleaned several times with deionized water and ultrasonic cleaning until there was no ethanol residue. The graphite felt fiber material was then left to stand and air dry to obtain the pretreated graphite felt fiber material.

[0036] Ion implantation with Ir and Ru: The pretreated graphite felt fiber material was placed in a metal vapor vacuum arc ion implantation device, and Ir and Ru were selected for ion implantation. The ion voltage was 60 keV, and the Ir ion implantation amount was 2.4 × 10⁻⁶. 7 ions / cm 2 The Ru metal ion implantation amount was 2.4 × 10⁻⁶. 7 ions / cm 2 ;

[0037] Carbon nanotubes are prepared by ALD method: Graphite felt fiber material is placed in an atomic layer deposition (ALD) apparatus and ethylene is introduced. Carbon atoms in the ethylene spontaneously accumulate on the surface of metal Ir / Ru to form a carbon nanotube structure through plasma discharge. The plasma discharge power is 55W, the discharge time of a single cycle is 1.5s, the ethylene flow rate is 75sccm, and each cycle includes purging the residual gas in the ALD apparatus with inert gas. Finally, a carbon-based fiber electrode containing Ir / Ru and carbon nanotubes is obtained.

[0038] Comparative Example 1

[0039] Pretreatment: The graphite felt fiber material was soaked in anhydrous ethanol for 12 hours to obtain the degreased graphite felt fiber material. Then, it was cleaned several times with deionized water and ultrasonic cleaning until there was no ethanol residue. The graphite felt fiber material was then left to stand and air dry to obtain the pretreated graphite felt fiber material.

[0040] Carbon nanotubes are prepared by ALD method: Graphite felt fiber material is placed in an atomic layer deposition (ALD) apparatus and ethylene is introduced. Carbon atoms in the ethylene spontaneously accumulate on the surface of metal Ir through plasma discharge to form a carbon nanotube structure. The plasma discharge power is 55W, the discharge time of a single cycle is 1.5s, the ethylene flow rate is 75sccm, and each cycle includes purging the residual gas in the ALD apparatus with inert gas. Finally, a carbon-based fiber electrode containing carbon nanotubes is obtained.

[0041] Comparative Example 2

[0042] Pretreatment: The graphite felt fiber material was soaked in anhydrous ethanol for 12 hours to obtain the degreased graphite felt fiber material. Then, it was cleaned several times with deionized water and ultrasonic cleaning until there was no ethanol residue. The graphite felt fiber material was then left to stand and air dry to obtain the pretreated graphite felt fiber material.

[0043] Ion implantation (Ir): The pretreated graphite felt fiber material was placed in a metal vapor vacuum arc ion implantation device, and Ir metal was selected for ion implantation. The ion voltage was 60 keV, and the Ir metal ion implantation amount was 1.5 × 10⁻⁶. 12 ions / cm 2 ;

[0044] Carbon nanotubes are prepared by ALD method: Graphite felt fiber material is placed in an atomic layer deposition (ALD) apparatus and ethylene is introduced. Carbon atoms in the ethylene spontaneously accumulate on the surface of metal Ir through plasma discharge to form a carbon nanotube structure. The plasma discharge power is 55W, the discharge time of a single cycle is 1.5s, the ethylene flow rate is 75sccm, and each cycle includes purging the residual gas in the ALD apparatus with inert gas. Finally, a carbon-based fiber electrode containing Ir and carbon nanotubes is obtained.

[0045] Next, we used the carbon-based fiber electrodes from Examples 1-5 and Comparative Examples 1-2 as negative electrodes to construct lithium batteries. We performed constant current discharge at 1A at room temperature (25°C) and 0°C, respectively, and calculated the battery capacity achievement rate at 0°C relative to room temperature. To ensure the comparability of experimental data, we ensured that all conditions (including the battery separator, current collector, casing, and the content of carbon nanotubes prepared by the ALD method) were consistent between the examples and the comparative examples, except for the Ir / Ru injection amount in the carbon-based fiber electrode. The obtained experimental results are shown in Table 1.

[0046] Table 1 Test data for each sample

[0047]

[0048] As shown in Table 1, the incorporation of Ir into the surface of graphite felt fiber materials via ion implantation not only improves the electrochemical activity of the carbon-based electrode but also serves as a catalyst for the subsequent ALD process to prepare carbon nanotubes. Studies have shown that an appropriate amount of metallic Ir can improve the low-temperature capacity achievement rate of the battery when the fiber electrode is used as the anode; however, excessive Ir has negative effects. Therefore, the amount of metallic Ir implanted needs to be controlled at 1.2 × 10⁻⁶. 4 ions / cm 2 -7.2×10 8 ions / cm 2 Furthermore, even better experimental results can be obtained when Ir and Ru are injected together.

[0049] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a carbon-based fiber electrode, characterized in that, The method for preparing the carbon-based fiber electrode includes the following steps: Pretreatment: Soak the graphite felt fiber material in anhydrous ethanol for 12-15 hours to obtain the degreased graphite felt fiber material. Then, use deionized water and ultrasonic cleaning several times until there is no ethanol residue. Finally, let the graphite felt fiber material stand and air dry to obtain the pretreated graphite felt fiber material. Ion implantation (Ir): The pretreated graphite felt fiber material is placed in a metal vapor vacuum arc ion implantation device, and metallic Ir is selected for ion implantation. The ion voltage is 60-75 keV, and the Ir metal ion implantation amount is 1.2 × 10⁻⁶. 4 ions / cm 2 -7.2×10 8 ions / cm 2 ; Carbon nanotubes are prepared by ALD method: Graphite felt fiber material is placed in an atomic layer deposition (ALD) apparatus and ethylene is introduced. Carbon atoms in the ethylene spontaneously accumulate on the surface of metal Ir through plasma discharge to form a carbon nanotube structure. The plasma discharge power is 55-60W, the discharge time of a single cycle is 1.5-2.0s, and the ethylene flow rate is 75-90sccm. Each cycle includes purging the residual gas in the ALD apparatus with inert gas. Finally, a carbon-based fiber electrode containing Ir and carbon nanotubes is obtained.

2. A preparation method as described in claim 1, characterized in that, The soaking time is 12 hours.

3. A preparation method as described in claim 1, characterized in that, The ion voltage is 60 keV.

4. A preparation method as described in claim 1, characterized in that, The plasma discharge power is 55W.

5. A preparation method as described in claim 1, characterized in that, The ethylene flow rate is 75 sccm.

6. A preparation method as described in claim 1, characterized in that, The discharge time for a single cycle is 1.5 seconds.

7. A carbon-based fiber electrode, characterized in that, The carbon-based fiber electrode is prepared by the method described in any one of claims 1-6.

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