Preparation, Modification Of Graphene Aerogel With High Specific Surface Area And The Study Of Its Properties

Graphene is a kind of superior material with many titles. It is considered as the thinnest in the universe and hardest material measured before. The charge carriers of Graphene show a giant charge mobility performance. It has the smallest effective quality, and also can move micrometer or long distances without any scattering at the room temperature. Graphene can support the current density6orders higher than the copper, shows outstanding thermal conductivity and stiffness properties. However, the pure2D graphene gets low reaction activity, and due to easy to come close to each other, graphene has low solubility, limits the improvement and application of graphene science. A plenty of research is focus on the modification and composite application of graphene in order to take full advantages of its remarkable performances in the electro-chemistry and many other aspects.This paper is aiming at the study of a new porous carbon material, graphene aerogel. KOH chemical modification and steam physical modification are chosen to optimize its structure and properties, so the material can have broad application prospects in the electro-chemical energy storage.The microstructure and the electrochemical properties of carbon aerogels were modified by the addition of the graphene which have a unique physical structure and excellent electrical properties. The effects of the addition of graphene on the carbon aerogel’s structure and characterization were mainly investigated. The scanning electron microscopy, N2adsorption/desorption and electrochemical measurements were used to analyze the morphology, structure and electrochemical properties of the samples. Results indicated that the graphene aerogels prepared by graphene modification had a wrinkled paper-like sheet structure, which was totally different from the sphere structure of carbon aerogels. The pore structure and the electrochemical properties of the composites were effectively improved and the specific surface area and the specific capacitance were2.7times and1.5times respectively than the sample which no addition of graphene.KOH activation has great influence on the structure and properties of graphene aerogel. The amount of KOH during activation was varied, and trends in BET SSA and electrochemical capacitance for the resulting RF-GO aerogel were found. For a given activation temperature of900℃, on increasing the activation ratio of KOH/RF-GO from1.0to7.0, both the gravimetric capacitance and the BET SSA increased, reaching a maximum an the ratio of3.0and4.0, respectively. The resulting RF-GO aerogels are light in weight, have high specific capacitance (271.79F/g), large BET surface area (2100m2/g) and excellent conductivity. These optimized data reveal a good application potential in supercapacitors.Steam activation also has great influence on the structure and properties of graphene aerogel. The analysis of BET result exhibits that activation has not only widen the micropore in the structure, but also created a lot of new pores, which leaded to a big increase of specific area, from611m2/g to1243m2/g at most. The electrochemical property of the sample obtained by steam activation got an obvious promotion, which showed the rather low resistance, excellent reversible cycle performance. The electrochemical specific capacitance were highly increased from96.3F/g to165.2F/g, the modification got a significant result.