TWI508360B - Method of making current collector - Google Patents

Description

Method for preparing current collector

The invention relates to a method for preparing a current collector, in particular to a method for preparing a current collector based on a carbon nanotube structure.

An important part of the electrochemical system of the current collecting system. In electrochemical cells, the surface of the current collector typically carries the electrode active material and contacts the electrolyte, providing an electron path for the electrochemical reaction to accelerate electron transfer and transport the electrons to an external circuit to form a current. Therefore, the performance of the current collector is closely related to the performance of the electrochemical cell.

Previous current collectors are typically prepared from conductive metal layers such as copper foil and aluminum foil. However, these metal layers are easily oxidized to form a passivation film, or are etched in the electrolyte to form an insulating layer, which greatly increases the contact resistance between the electrode active material and the metal layer, thereby reducing the contact resistance. The capacity and energy conversion efficiency of electrochemical cells.

In view of this, it is necessary to provide a method of preparing a current collector having a small contact resistance with an electrode active material.

A method for preparing a current collector, comprising: providing a carbon nanotube layer having an opposite first surface and a second surface, the carbon nanotube layer comprising a plurality of carbon nanotubes, at least a portion The carbon nanotubes are spaced apart to form a plurality of micropores; a first metal layer is plated on the first surface of the carbon nanotube layer, and a second metal layer is plated on the second surface of the carbon nanotube layer to form a carbon nanotube composite layer; and tearing the carbon nanotube composite layer to divide the carbon nanotube layer into a first sub-carbon nanotube layer and a second sub-carbon nanotube layer, A first sub-carbon nanotube layer is attached to a surface of the first metal layer, and the second sub-carbon nanotube layer is attached to a surface of the second metal layer.

A method for preparing a current collector, comprising: providing a first metal layer; providing a carbon nanotube layer, wherein the carbon nanotube layer comprises an opposite first surface and a second surface, the carbon nanotube layer a first surface is attached to the surface of the first metal layer; a second metal layer is plated on the second surface of the carbon nanotube layer to form a carbon nanotube composite layer; and the naphthalene is torn open a carbon nanotube composite layer, wherein the carbon nanotube layer forms a first sub-carbon nanotube layer attached to a surface of the first metal layer, and a second sub-carbon nanotube layer is attached to the The surface of the second metal layer forms two current collectors.

Compared with the prior art, in the method for preparing a current collector provided by the present invention, the carbon nanotubes are firmly clamped between the first metal layer and the second metal layer by electroplating, and then formed by separation. The current collector can obtain more than two current collectors at a time, so that the carbon nanotube layer is firmly fixed to the surface of the first metal layer or the second metal layer, and the metal layer is directly contacted with the electrolyte. Thereby, the corrosion reaction between the electrolyte and the metal layer can be prevented, the influence of the corrosion product on the contact resistance between the current collector and the electrode material layer, the battery capacity and the conversion efficiency are improved.

10‧‧‧ Collector

110‧‧‧Nano carbon tube layer

120‧‧‧First metal layer

130‧‧‧Second metal layer

111‧‧‧ first surface

112‧‧‧Micropores

113‧‧‧ second surface

11‧‧‧Nano Carbon Tube Composite Layer

114‧‧‧First sub-carbon nanotube layer

116‧‧‧Second sub-carbon nanotube layer

140‧‧‧electrode

1 is a flow chart showing a method of preparing a current collector according to a first embodiment of the present invention.

2 is a schematic view showing the structure of a carbon nanotube film in a current collector according to a first embodiment of the present invention.

3 is a schematic structural view of a carbon nanotube layer in a current collector according to a first embodiment of the present invention.

Figure 4 is a flow chart showing the plating of a metal layer on the surface of the carbon nanotube layer in the first embodiment of the present invention.

FIG. 5 is a flow chart of tearing apart the carbon nanotube composite layer in the method for preparing a current collector according to the first embodiment of the present invention.

FIG. 6 is a flow chart of a method for preparing a current collector according to a second embodiment of the present invention.

The current collector and the preparation method thereof provided by the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

Referring to FIG. 1, the present invention also provides a method for preparing a current collector 10, comprising the following steps:

Step S10, providing a carbon nanotube layer 110, the carbon nanotube layer 110 includes an opposite first surface 111 and a second surface 113;

In step S11, a first metal layer 120 is plated on the first surface 111 of the carbon nanotube layer 110, and a second metal layer 130 is plated on the second surface 113 of the carbon nanotube layer 110 to form a Carbon tube composite layer 11; and

Step S12, tearing the carbon nanotube composite layer 11 to divide the carbon nanotube layer 110 into a first sub-carbon nanotube layer 114 and a second sub-carbon nanotube layer 116, the first The sub-carbon nanotube layer 114 is attached to the surface of the first metal layer 120, and the second sub-carbon nanotube layer 116 is attached to the surface of the second metal layer 130.

Referring to FIG. 2 and FIG. 3 together, in step S10, the carbon nanotube layer 110 may be disposed on a surface of a substrate (not shown), or may be suspended by a fixed frame, thereby The carbon nanotube layer 110 can be suspended in a subsequent solution. The substrate may be an insulating substrate or a conductive substrate. Since the carbon nanotube layer 110 is a self-supporting structure, the carbon nanotube layer 110 can be suspended by a support provided at intervals. The carbon nanotube structure may comprise a plurality of stacked carbon nanotube membranes, the plurality of carbon nanotube membranes being stacked and arranged in a cross, and the carbon nanotubes in different layers of carbon nanotube membranes are interwoven A mesh structure. Each of the carbon nanotube membranes comprises a plurality of carbon nanotubes, the plurality of carbon nanotubes being arranged in a preferred orientation in the same direction. The preferred orientation means that the majority of the carbon nanotubes in the carbon nanotube film extend substantially in the same direction. Moreover, the overall direction of extension of the majority of the carbon nanotubes is substantially parallel to the surface of the carbon nanotube film. Further, most of the carbon nanotubes in the carbon nanotube membrane are connected end to end by van der Waals force. The carbon nanotube layer 110 includes a plurality of micropores 112 that extend through the carbon nanotube layer 110 in a direction perpendicular to the thickness of the carbon nanotube layer 110. In this embodiment, the carbon nanotube layer 110 is suspended by a fixed frame.

In step S11, the first metal layer 120 is formed on the first surface 111 of the carbon nanotube layer 110 by electroplating. Referring to FIG. 4 , specifically, the plating method of the first metal layer 120 includes the following steps:

Step S111, providing a solution containing metal ions;

Step S112, the carbon nanotube layer 110 is immersed in the solution, and the first surface 111 and the second surface 113 of the carbon nanotube layer 110 are exposed to the solution and parallel to an electrode sheet in the solution. And interval setting;

Step S113, forming a potential difference between the carbon nanotube layer 110 and the electrode sheet, reducing metal ions to metal and plating on the first surface 111 and the second surface 113 of the carbon nanotube layer 110. Forming the first metal layer 120 and the second metal layer 130.

In step S111, the method of forming the solution containing the metal ions is not limited as long as metal ions can be formed in the solution. The concentration of the metal ions can be selected according to actual needs such as the thickness of the first metal layer 120 and the second metal layer 130. In this embodiment, the solution forms a copper ion solution by dissolving copper sulfate in water.

In step S112, the carbon nanotube layer 110 is spaced apart from the electrode sheet, and the distance between the spacers may be 0.5 cm to 3 cm, which may also be selected according to actual needs. The electrode sheet comprises an inert graphite electrode sheet, a platinum electrode sheet, a stainless steel electrode sheet and a layered carbon nanotube structure, the area of which is greater than or equal to the area of the carbon nanotube film. The electrode sheet functions as an electrode, and as long as the conductivity is good and inert, it can meet the requirements. The carbon nanotube layer 110 is suspended in the metal ion solution. Specifically, since the carbon nanotube layer 110 is suspended by a fixing frame, when it is immersed in the metal ion solution, it is located between the fixed frames. The carbon nanotube layer 110 is suspended in the solution. In this embodiment, the electrode sheet is a copper sheet, and an area of the copper sheet is larger than an area of the carbon nanotube layer 110.

In step S113, a potential difference is formed between the carbon nanotube layer 110 and the electrode sheet, and the electrode sheet is connected to the anode of the power source as an anode, and the carbon nanotube layer 110 is connected to the cathode of the power source as a cathode, and the metal ion is used as a cathode. A reduction reaction occurs on the carbon nanotube layer 110 to form metal particles and adhere to the tube wall of the carbon nanotube. In addition, during the electroplating process, the surface of the carbon nanotubes in the carbon nanotube layer 110 forms a plurality of dangling bonds, such that the metal particles pass through the dangling bonds of the carbon nanotubes and the carbon nanotubes. Closely integrated. Further, the metal particles are connected to each other on the surface of the carbon nanotube layer 110 to form a continuous structure, so that the first metal layer 120 and the second metal layer 130 are both continuous structures. In addition, a portion of the metal ions are reduced to a surface of the carbon nanotubes where the metal particles adhere to the micropores 112, and the first metal layer 120 and the second metal layer 130 are fused to each other at the position of the micropores 112 to form an integral structure. .

The method of forming a potential difference between the anode and the cathode includes applying a constant current, a constant voltage, a scanning potential, or the like between the anode and the cathode. In the present embodiment, the method of forming a potential difference between the positive electrode and the negative electrode is to apply a constant voltage, and a voltage applied between the anode and the cathode is 0.5 to 1.2 volts for a time of 0.5 hours to 4 hours.

Further, in step S112, the first metal layer 120 and the second metal layer 130 may also be formed in steps. Specifically, the second surface 113 of the carbon nanotube layer 110 may be attached to the first surface 113. a substrate (not shown), only exposing the first surface 111 to the metal ion solution, first forming a first metal layer 120 on the first surface 111; and then plating the carbon nanotube layer of the first metal layer 120 The 110 is reversed, exposing the second surface 113 of the carbon nanotube layer 110 to a metal ion solution, and disposed opposite the electrode sheet, and then plating the second metal layer 130 on the second surface 113.

Further, in the process of plating the second metal layer 130, a portion of the second metal layer 130 penetrates through the micro holes 112 to contact the first metal layer 120 and form an integrated structure, and the carbon nanotube layer 110 is The first metal layer 120 and the second metal layer 130 are sandwiched between the first metal layer 120 and the second metal layer 130. It can be understood that, since the carbon nanotube layer 110 is immersed in the metal ion solution, the metal ions are simultaneously plated on the first surface 111 and the second surface 113 of the carbon nanotube layer 110, that is, The second metal layer 130 and the first metal layer 120 may be formed simultaneously.

After the second metal layer 130 is formed by electroplating, the method further includes a step of cleaning and drying the carbon nanotube layer 110, the first metal layer 120 and the second metal layer 130 by using a cleaning solution. The remaining impurities are removed, and the first metal layer 120 and the second metal layer 130 are more firmly bonded to the surface of the carbon nanotube layer 110.

In step S12, the carbon nanotube composite layer 11 can divide the carbon nanotube composite layer 11 into two by applying opposite forces on opposite surfaces of the carbon nanotube composite layer 11. Two parts. Referring to FIG. 5 together, the method for disconnecting the carbon nanotube composite layer 11 includes the following steps:

Step S121, applying opposite forces F, F' to the opposite surfaces of the carbon nanotube composite layer 11;

In step S122, the applied force F, F' is continuously applied, and the carbon nanotube layer 110 in the carbon nanotube composite layer 11 is separated from the middle and attached to the first metal layer 120 and the second metal, respectively. On the surface of layer 130, two current collectors 10 are formed.

In step S121, the magnitudes of the two forces F, F' may be selected according to the thickness of the carbon nanotube layer 110, the first metal layer 120, and the second metal layer 130, so that the The carbon nanotube layer 110 can be separated. The two forces F, F' are applied to the opposite surfaces of the carbon nanotube composite layer 11, so that the carbon nanotube composite layer 11 can be separated in the thickness direction, that is, the carbon nanotube layer 110 is divided into two. The first sub-carbon nanotube layer 114 and the second sub-nanocarbon tube layer 116 having substantially the same sheet area are respectively attached to the surfaces of the first metal layer 120 and the second metal layer 130, thereby forming two The current collectors 10 are substantially the same in area, and the area of the current collectors 10 is substantially equal to the area of the carbon nanotube composite layer 11 before division. That is, the area of the first sub-carbon nanotube layer 114 and the second sub-carbon nanotube layer 116 is substantially equal to the area of the carbon nanotube layer 110 before division.

The separation method may be selected as needed, for example, by tape attached to the surfaces of the first metal layer 120 and the second metal layer 130, and then the tape is pulled apart. It is also possible to separate the carbon nanotube composite layer 11 by using a gripping tool such as a tweezers. Further, in the case where the thickness of the carbon nanotube composite layer 11 satisfies the condition, the carbon nanotube composite layer 11 may be separated by a cutting tool such as a blade. In the present embodiment, the force F, F' is applied to the carbon nanotube composite layer 11 by tearing the carbon nanotube composite layer 11.

It can be understood that one surface of the carbon nanotube composite layer 11 can also be fixed, and the carbon nanotube composite layer can be applied by applying a force F to the other surface of the carbon nanotube composite layer 11. 11 separate.

In step S122, in the process of continuously applying the forces F, F', the carbon nanotube layer 110 is separated by the forces F, F' to form the first sub-carbon nanotube layer 114 and the second sub-portion. a carbon nanotube layer 116, and the first sub-carbon nanotube layer 114 is attached to the surface of the first metal layer 120 and passes through a dangling bond on the surface of the carbon nanotube and the first metal layer 120 The second sub-carbon nanotube layer 116 is attached to the surface of the second metal layer 130 and passes through a dangling bond on the surface of the carbon nanotube to the surface of the second metal layer 130. During the separation process, the first sub-carbon nanotube layer 114 and the second sub-carbon nanotube layer 116 have substantially the same thickness and are uniformly distributed on the first metal layer 120 and the second metal layer 130, respectively. s surface. The carbon nanotubes in the first sub-carbon nanotube layer 114 are substantially parallel to the surface of the first metal layer 120, and the carbon nanotubes in the second sub-carbon nanotube layer 116 are substantially parallel to The surface of the second metal layer 130.

The method for preparing a current collector according to an embodiment of the present invention has the following advantages: forming a first metal layer and a second metal layer on a surface of the carbon nanotube layer by electroplating, enabling the first metal layer and the first metal layer The two metal layers are firmly bonded to the surface of the carbon nanotube layer to avoid drift or shedding of the carbon nanotubes in subsequent applications; the carbon nanotube layer blocks the metal layer and is corrosive The electrolyte is in direct contact, thereby preventing the corrosion reaction between the electrolyte and the metal layer, so that the metal layer is not corroded, and the influence of the corrosion product on the contact resistance between the current collector and the electrode material layer is reduced; Since the carbon nanotube layer has good electrical conductivity, and the carbon nanotube layer is in direct contact with the electrode material layer and can be well combined with the electrode material layer, thereby further reducing the current collector and Contact resistance between the electrode active material layers; finally, by forming the first metal layer and the second metal layer by electroplating and then tearing them apart, two current collectors can be prepared at one time, thereby improving Said fluid current production efficiency.

Referring to FIG. 6 together, a second embodiment of the present invention provides a method for preparing a current collector 10, including the following steps:

Step S20, providing a first metal layer 120;

In step S21, a carbon nanotube layer 110 is provided. The carbon nanotube layer 110 includes an opposite first surface 111 and a second surface 113. The first surface 111 of the carbon nanotube layer 110 is attached to the first surface 111. a surface of the first metal layer 120;

Step S22, plating a second metal layer 130 on the second surface 113 of the carbon nanotube layer 110 to form a carbon nanotube composite layer 11;

Step S23, tearing the carbon nanotube composite layer 11 so that the carbon nanotube layer 110 forms a first sub-carbon nanotube layer 114 attached to the surface of the first metal layer 120. A second sub-carbon nanotube layer 116 is attached to the surface of the second metal layer 130.

The method for preparing the current collector 10 provided by the second embodiment of the present invention is substantially the same as that of the first embodiment, except that the first surface 111 of the carbon nanotube layer 110 and the first metal layer 120 are attached. Attached, a second metal layer 130 is then deposited on the second surface 113.

In step S21, the first metal layer 120 is tightly coupled to the carbon nanotube layer 110, and the first metal layer 120 functions to support the carbon nanotube layer 110, the first metal The thickness of layer 120 can be selected as needed to support the carbon nanotube layer 110. In this embodiment, the first metal layer 120 may be 10 micrometers, so that the current collector 10 has a certain mechanical strength.

In step S22, during the deposition of the second metal layer 130, the second metal layer 130 at the position corresponding to the micropores 112 will penetrate the micropores 112 of the carbon nanotube layer 110, and A metal layer 120 is fused together to firmly secure the carbon nanotube layer 110 between the first metal layer 120 and the second metal layer 130.

In summary, the present invention has indeed met the requirements of the invention patent, and has filed a patent application according to law. However, the above description is only a preferred embodiment of the present invention, and it is not possible to limit the scope of the patent application of the present invention. Equivalent modifications or variations made by those skilled in the art in light of the spirit of the invention are intended to be included within the scope of the following claims.

no

10‧‧‧ Collector

110‧‧‧Nano carbon tube layer

120‧‧‧First metal layer

130‧‧‧Second metal layer

111‧‧‧ first surface

112‧‧‧Micropores

113‧‧‧ second surface

11‧‧‧Nano Carbon Tube Composite Layer

114‧‧‧First sub-carbon nanotube layer

116‧‧‧Second sub-carbon nanotube layer

Claims (12)

A method for preparing a current collector, comprising:
Providing a carbon nanotube layer having an opposite first surface and a second surface, the carbon nanotube layer comprising a plurality of carbon nanotubes, at least a portion of the carbon nanotubes being spaced apart to form a plurality of microtubes hole;
Depositing a first metal layer on the first surface of the carbon nanotube layer, and plating a second metal layer on the second surface of the carbon nanotube layer to form a carbon nanotube composite layer; and tearing The carbon nanotube composite layer divides the carbon nanotube layer into a first sub-carbon nanotube layer and a second sub-carbon nanotube layer along a thickness direction thereof, the first sub-nanocarbon tube A layer is attached to a surface of the first metal layer, and the second sub-carbon nanotube layer is attached to a surface of the second metal layer. The method for preparing a current collector according to claim 1, wherein the carbon nanotube layer is a self-supporting structure composed of a plurality of carbon nanotubes, and the plurality of micropores are along the carbon nanotube layer. The thickness direction penetrates the carbon nanotube layer. The method of preparing a current collector according to claim 2, wherein the first metal layer and the second metal layer corresponding to the position of the micropore in the electroplating process are fused to each other to form an integral structure. The method of preparing a current collector according to claim 2, wherein the plating process of the first metal layer and the second metal layer comprises the following steps:
Providing a solution containing a metal ion;
Immersing the carbon nanotube layer into the solution and disposed in parallel with and spaced apart from an electrode sheet in the solution, the first surface and the second surface of the carbon nanotube layer being exposed to the metal ion solution ;
Forming a potential difference between the carbon nanotube layer and the electrode sheet, causing metal ions to reduce metal and electroplating on the first surface and the second surface of the carbon nanotube layer to form the first metal layer And a second metal layer. The method of preparing a current collector according to claim 4, wherein the first metal layer forms a continuous structure on the first surface of the carbon nanotube layer, and the second metal layer is in the nanometer. The second surface of the carbon tube layer forms a continuous structure. The method for preparing a current collector according to claim 4, wherein the carbon nanotube layer is immersed in the metal ion solution and suspended, and the carbon nanotube layer located in the fixed frame is suspended. The method for preparing a current collector according to claim 1, wherein the carbon nanotube layer comprises a plurality of stacked and interdigitated carbon nanotube membranes, and the plurality of carbon nanotube membranes pass through a van der Waals force In combination, each of the carbon nanotube membranes comprises a plurality of carbon nanotubes arranged in a preferred orientation in the same direction, and the carbon nanotubes in the adjacent carbon nanotube membranes have an intersection angle α, and the α is greater than 0 degrees. And less than or equal to 90 degrees. The method for preparing a current collector according to claim 1, wherein the tearing the carbon nanotube composite layer along the thickness direction of the carbon nanotube composite layer comprises:
Applying forces F, F' in opposite directions to opposite surface directions of the carbon nanotube composite layer;
The force F, F' is continuously applied, and the carbon nanotube layers in the carbon nanotube composite layer are separated from the middle, and are respectively attached to the surfaces of the first metal layer and the second metal layer to form two a current collector. The method of producing a current collector according to claim 8, wherein the application direction of the force F is perpendicular to the first surface, and the application direction of the force F' is perpendicular to the second surface. The method of preparing a current collector according to claim 8, wherein the carbon nanotubes in the first sub-carbon nanotube layer are parallel to a surface of the first metal layer; the second sub-nanocarbon The carbon nanotubes in the tube layer are parallel to the surface of the second metal layer. A method for preparing a current collector, comprising:
Providing a first metal layer;
Providing a carbon nanotube layer, the carbon nanotube layer including an opposite first surface and a second surface, the first surface of the carbon nanotube layer is attached to a surface of the first metal layer;
Depositing a second metal layer on the second surface of the carbon nanotube layer to form a carbon nanotube composite layer; and tearing the carbon nanotube composite layer to form the carbon nanotube layer A first sub-carbon nanotube layer is attached to the surface of the first metal layer, and a second sub-carbon nanotube layer is attached to the surface of the second metal layer to form two current collectors. The method of preparing a current collector according to claim 11, wherein, in the deposition of the second metal layer, the second metal layer corresponding to the position of the micropore penetrates the micropores of the carbon nanotube layer, and Blending with the first metal layer.