凯发

We find that the graphene samples provided by different suppliers are significantly different from one to another, which is due to the different process during preparation. However, there is still no state standards to define graphene and how to characterize these materials. This will obviously confuse the customers, which is not favorable for the commercialization of graphene. Actually, the characterization plays an important role in quality control of graphene during scale-up production, application in different fields and trading in the markets. Moreover, these methods should be easy, fast, cheap and repeatable, so as to meet the requirements for not only academy but also industry. Thus I will also talk about several traditional characterization methods which we employed for a better understanding of graphene. For example, the investigation on surface chemistry by chemical titration, the determination of chemical composition such as ash, oxygen and sulfur contents, and the evaluation of various physical properties such as density, electrical and thermal conductivity.

Since 2010, there is a surge in industrialization of graphene in China, several pilot or industrial plants with nominated production capability of over ten to hundred tons were set up. On Dec 2013, we also built up our own pilot plant with capability of 1 ton per year in Taiyuan, China. In the process, the oxidation-reduction approach was employed with natural graphite powder as the raw material, so as yield the cost-effective chemically derived graphene powders. Afterwards, the exploitation for commercial applications of these materials become a great challenge to the sustainable development of graphene.

With high specific surface area, excellent electric conductivity and tunable surface chemistry, chemically derived graphene is among one of the most exciting area for the next-generation electrode for supercapacitors in scientific community. However, when we go further to the industry, these low dimensional nano-carbons really bring trouble to the industrial processing. For example, the ultralow bulk density (3~5 g/L) of the powder is not favorable to improve the coating density of the electrode sheets, and will also consume more binder. Besides, the agglomeration nature of nanoparticles with high surface energy can also impede the utilization of the ultimate property of graphene. Until then, it become gradually clear that maybe graphene is more suitable as conductive additives, rather than major energy storage materials in supercapacitor, technically and economically. In this presentation, combining with seven years of experience in industrialization of graphene towards application in energy storage. I will talk about the several issues and inspirations that we are tackling for an easier application of graphene in supercapacitor. For example, we adjust the surface oxygen functional groups for an optimized electrochemical performance, investigate on the dispersion behavior of graphene in different solvents, as well as fabricate the macro-assemblies or nanocomposites for binderless electrode etc.