Preparation method of graphene current collector

Abstract

The invention provides a preparation method of a graphene current collector. The preparation method comprises the following steps: (1) mixing graphene and a binder with a solvent to obtain a graphene suspension liquid, wherein the content of graphene in the graphene suspension liquid is 0.01 to 10 mg / mL; (2) putting the graphene suspension liquid and a substrate in a container at the same time, and then forming a graphene thin film on the surface of the substrate through self-assembling; and (3) taking the graphene thin film out together with the substrate, and carrying out processing at the temperature of 400 to 1500 DEG C under a protective atmosphere to obtain the graphene current collector.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to a method for preparing a graphene current collector applied to lithium ion batteries. Background technique [0002] Lithium-ion batteries are widely used in energy storage devices for portable electronic devices due to their good overall performance. In the manufacturing process of lithium-ion battery pole pieces, generally, granular active materials such as carbon particle suspensions are directly coated on the surface of substrates such as aluminum foil or copper foil, and the active materials are fixed on the substrate surface through a binder. However, this method has the following two defects: 1) the contact area between the granular active material and the substrate is limited, resulting in a large interface resistance, which causes an increase in the internal resistance of the battery; 2) due to the use of granular active materials, However, the bonding stre...

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Problems solved by technology

However, this method has the following two defects: 1) the contact area between the granular active material and the substrate is limited, resulting in a large interface resistance, which causes an increase in the internal resistance of the battery; 2) due to the use of granular active materials, However, the bonding strength of the binder is limited. During the continuous charging and discharging process, the granular active material is easy to swell and separate from the substrate, resulting in further increase of the internal resistance of the battery, which affects the cycle life and safety performance of the battery.

However, the increase in the amount of binder will cause a series of adverse effects on battery performance, including the increase of battery internal resistance, the decrease of energy density and power density, the shortening of cycle life, and the increase of battery heat generation, etc.

However, special treatments such as chemical corrosion and corona will cause a certain degree of surface damage to the current collector, reduce the strength of the foil, and seriously affect the subsequent processing of finished products, and the cost is high, which is not conducive to the needs of mass production.