Method for preparing carbon-coated current collector by Joule heating and application of carbon-coated current collector

Abstract

The invention relates to the technical field of energy storage, in particular to a method for preparing a carbon-coated current collector through Joule heating and application of the carbon-coated current collector, and according to the method, the surface of a metal matrix is uniformly coated with a carbon material, so that the thermal stability, corrosion resistance and pole piece conductivity of the metal matrix are improved. The current collector can be widely applied to flexible batteries, especially aqueous ion batteries and lithium ion batteries, and can be used as a current collector to improve the electrochemical performance and mechanical stability of the batteries.

Description

Technical Field

[0001] The present invention relates to the field of energy storage technology, and in particular to a method for preparing a carbon-coated current collector using Joule heating technology and an application thereof in a battery. Background Art

[0002] With the rapid development of portable electronic devices and electric vehicles, there is a growing demand for efficient, safe, and stable energy storage systems. Among the many battery technologies, flexible batteries have attracted widespread attention due to their potential for application in wearable devices and flexible electronics. Traditional metal current collectors, such as copper foil and aluminum foil, although they have good conductivity, have insufficient mechanical stability in flexible batteries. In addition, these metal foils are susceptible to corrosion during battery charging and discharging, affecting the battery life and safety.

[0003] To solve these problems, researchers have explored a variety of new current collector materials, such as carbon nanotubes and graphene. These materials have excellent conductivity, flexibility and chemical stability, but the traditional graphene oxide (GO) manufacturing process is time-consuming and energy-intensive, and product performance needs to be improved. How to evenly and firmly coat them on the surface of metal foil is still a technical challenge. Existing coating technologies, such as chemical vapor deposition (CVD) and physical vapor deposition (PVD), are often costly and time-consuming, which is not conducive to large-scale production. Summary of the invention

[0004] In view of the above problems, the present invention provides a method for preparing a carbon-coated current collector using Joule heating technology, which has the advantages of low cost, high efficiency, and simple operation. Through the method of the present invention, a uniform and firm carbon material layer can be quickly formed on the surface of the metal substrate, significantly improving the thermal stability and corrosion resistance of the current collector and the conductivity of the pole piece, thereby improving the overall performance of the battery.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] Preparation method:

[0007] The graphene oxide is added into the ethanol solution and ultrasonically mixed to prepare a graphene oxide suspension.

[0008] The carbon nanotubes are added into the ethanol solution and ultrasonically mixed to prepare a carbon nanotube suspension.

[0009] The graphene oxide suspension and the carbon nanotube suspension are mixed, ultrasonicated and vibrated to form a uniform mixed slurry. In the mixed slurry, the mass of the carbon nanotubes accounts for 10-20% of the total weight of the carbon material.

[0010] Drop the mixed slurry on the surface of the current collector, scrape it flat with a scraper, and dry it naturally to form a coating.

[0011] Alternatively, the slurry is applied to the surface of the current collector using a coating machine or surface spraying equipment, and dried naturally to form a coating.

[0012] Wherein, the coating thickness is 1 to 20 μm.

[0013] Under argon atmosphere, the coated current collector is transferred through two rotating graphite rollers driven by controllable micromotors at a speed of 0.05-0.2m / min. The distance between the horizontal graphite rollers can be adjusted according to the resistance of the sample and the power supply capacity. The direct current passing through the sample is provided by an automatic range DC power supply, and the voltage is applied to the graphite roller. The coated current collector is quickly heated by Joule heating technology, and the temperature is controlled at 1000-3500K and the time is controlled at 30-60s to achieve rapid reduction and coating of carbon materials.

[0014] The current collector material includes one or more of stainless steel, nickel, titanium, aluminum, zinc or copper, and the morphology includes mesh or foil, with a thickness of 5 μm to 1 mm.

[0015] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0016] Current collector characteristics:

[0017] A highly conductive network is built from cross-linked one-dimensional carbon nanotubes that are layered between densely packed graphene oxide nanosheets, transforming graphene oxide-based materials from insulators to conductors.

[0018] The prepared carbon-coated current collector has high conductivity (0.7×10 6 S·m -1 above).

[0019] It has good thermal stability and can be firmly attached to the surface of the current collector matrix, which can enhance the adhesion between the active material of the electrode and the current collector, reduce the problem of active particle peeling during the electrode cycle, and maintain structural integrity at higher temperatures.

[0020] Exhibits excellent mechanical stability and can withstand mechanical damage such as bending, folding, puncture or cutting.

[0021] Battery Application:

[0022] The prepared carbon-coated current collector is applied to aqueous ion batteries and lithium ion batteries as a current collector.

[0023] The battery exhibits excellent cycling stability and rate capability, as well as high tolerance to mechanical deformation.

[0024] Through the above technical scheme, the present invention successfully solves the problems of insufficient conductivity and mechanical stability of traditional metal current collectors in flexible batteries, while improving the safety and energy density of the battery. It can mass-produce high-performance carbon-coated current collectors, providing new material options for the development of flexible batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a cycling performance diagram of the aqueous lithium-ion soft-pack battery assembled in Example 1. DETAILED DESCRIPTION

[0026] The technical scheme of the present invention is further described below by specific implementation methods. The embodiments described herein are only to help understand the present invention and should not be regarded as specific limitations of the present invention. The described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Unless otherwise defined, the professional terms used below are consistent with the meanings understood by professionals and technicians in the field; unless otherwise specified, the raw materials and reagents involved in this article can be purchased from the market or prepared by publicly known methods.

[0027] Embodiment 1:

[0028] Graphene oxide was added into the ethanol solution and ultrasonically mixed to prepare a graphene oxide (GO) suspension.

[0029] The carbon nanotubes are added into the ethanol solution and ultrasonically mixed to prepare a carbon nanotube (CNT) suspension.

[0030] Prepare a graphene oxide suspension with a concentration of 3 mg / mL. Prepare a carbon nanotube suspension with a concentration of 0.5 mg / mL. Take 100 mg of each of the two suspensions, sonicate, and shake to mix into a uniform slurry.

[0031] Drop the slurry on the surface of the stainless steel foil, apply it evenly with a scraper, and dry it naturally at room temperature to form a uniform coating.

[0032] In a glove box, using an argon atmosphere, the rotating graphite roller transfer speed was adjusted to 0.1 m / min, and the coating was heated using Joule heating technology. The heating temperature was controlled to 2936 K and the time was controlled to 60 s. After cooling, a carbon-coated current collector was obtained.

[0033] The carbon-coated current collector exhibits a 0.76×10 6 S·m -1The prepared carbon-coated current collector was applied to aqueous ion batteries, using LiMn2O4 as the active material to prepare the positive electrode sheet, using NaTi2(PO4)3 as the active material to prepare the negative electrode sheet, using 1M Li2SO4 as the electrolyte, assembling aqueous lithium-ion soft-pack batteries, and testing their electrochemical performance. The results are as follows Figure 1 As shown. The initial discharge capacity of the battery is 105.5 mAh g -1 , with a capacity retention rate as high as 95.66% after 150 cycles.

Claims

1. A method for preparing a carbon-coated current collector using Joule heating, characterized in that: The following steps are involved: Adding graphene oxide to an ethanol solution and mixing by ultrasonication to prepare a graphene oxide suspension; Adding carbon nanotubes into an ethanol solution and mixing by ultrasonication to prepare a carbon nanotube suspension; The graphene oxide suspension and the carbon nanotube suspension are mixed, ultrasonicated and vibrated to form a uniform mixed slurry, wherein the mass of the carbon nanotubes accounts for 10-20% of the total weight of the carbon material; The mixed slurry is evenly coated on the surface of the current collector to form a coating, and is placed at room temperature to dry naturally; In an argon atmosphere, the coating is quickly heated by Joule heating technology, with the temperature controlled at 1000-3500K and the time controlled at 30s-60s to achieve rapid reduction and coating of the carbon material.

2. The method according to claim 1, characterized in that The current collector material includes one or more of stainless steel, nickel, titanium, aluminum, zinc or copper, and the morphology includes mesh or foil, with a thickness of 5 μm to 1 mm.

3. The method according to claim 1, characterized in that The method of coating the carbon material coating on the current collector includes one or more of blade coating, spray coating or spin coating, and the coating thickness is 1 to 20 μm.

4. Use the carbon-coated current collector according to any one of claims 1 to 3 as a current collector for aqueous ion batteries and lithium ion batteries.

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