Supercapacitor flexible self-supporting full-carbon electrode with graphene as binder and preparation method thereof

Abstract

The invention relates to a supercapacitor flexible self-supporting full-carbon electrode with graphene as a binder. The electrode is composed of two components of a micro-grade porous carbon materialand the graphene, and the thickness is 10-200 [mu]m, wherein the ratio of the porous carbon particle with dimension of 2-10 [mu]m as the active material in the total electrode mass is 80-95%. The ratio of the graphene with dimension of 3-15 [mu]m and slice layer thickness of 1-5 as the binder in the total electrode mass is 5-20%. The whole electrode has high flexibility and can be directly used asthe electrode of the flexible supercapacitor. The invention further provides a preparation method of the carbon electrode, wherein the preparation method comprises the steps of dispersing the porouscarbon into graphene oxide solution, performing vacuum pumping and filtering on the mixed solution for forming a film, and finally performing high-temperature thermal treatment on the composite film of the porous carbon and the graphene oxide through protection of an inert atmosphere, thereby converting the graphene oxide to graphene through reduction reaction, thereby obtaining the porous carbonmaterial/graphene flexible self-supporting composite film electrode. In the electrode, the porous carbon is the active material, and the graphene is used as the binder, a conductive agent and an auxiliary active material. Compared with a traditional electrode forming method in which insulating high-molecular materials such as PTFE and PVDF are used as the binder, the carbon electrode which is prepared through using the graphene as a multifunctional conductive binder has higher specific capacity and better multiplying power performance. Furthermore the electrode forming method has advantages ofsimple operation and environment-friendly performance.

Description

technical field [0001] The invention belongs to the technical field of energy storage electrodes and their preparation, and in particular relates to a carbon electrode for supercapacitors and a preparation method thereof. Background technique [0002] Due to the advantages of high power and long cycle life, the broad application prospects of supercapacitors in the fields of electric vehicles, aerospace, uninterruptible power supplies, and daily electronic consumer goods have attracted people's attention. Porous carbon materials are the most commonly used electrode materials for commercial supercapacitors due to their high specific surface area, controllable pore size, and low price. Electrode forming is an essential part of using powdered porous carbon materials for supercapacitors. Traditional supercapacitor electrodes are prepared by blending active materials, conductive agents, and binders, coating or rolling on current collectors (nickel foam or aluminum foil). The wid...

AI Technical Summary

Problems solved by technology

However, the use of polymer binders to prepare carbon electrodes has obvious limitations: (1) Polymer binders such as PTFE and PVDF are insulators, and their addition will increase the electrode resistance, which is not conducive to the power performance of supercapacitors; (2) The binder usually accounts for 5-20% of the electrode mass, but it does not contribute to the capacity of the electrode, and may block some pores of the carbon material, reducing the energy storage density of the electrode; (3) containing Fluorine binders will produce highly toxic fluorides during incineration, which will cause serious pollution to the environment; (4) Although the electrode prepared by coating or rolling the active material on the metal current collector with a polymer binder has good strength, But usually poor flexibility, can not be applied to wearable and flexible electronic devices

The addition of a small amount of carbon nanoparticles improves the rate performance of the electrode, but also due to the low specific surface of the electrode (only 370 m 2 / g), lower specific capacity

In addition, the degree of reduction of graphene oxide at 200 °C is not high, resulting in poor rate performance of the composite flexible electrode.

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