凯发

Large scale production of graphene materials is one of the critical problems in its basic research and for industrial application. Chemical methods such as the graphite oxide route [1-3] offer possibilities of producing graphene on a scale of tons. To further reduce the cost of produce graphene, we have developed a weak oxidation technique for producing low defect and high quality graphene materials. 

During the development of the technique, the effects of parent graphite and oxidation conditions on the size of graphene oxide sheets upon exfoliation have been studied systematically. Parameters such as the crystalline size and orientation of the parent graphite, the amount of potassium permanganate and sulfuric acid, as well as the oxidation time were optimized. We discovered that, in contrast to the traditional graphite oxide routes,[4,5] only half of the oxidants are required while maintain the integrity of π-π conjugated structure as much as possible, and a limited amount of oxidation groups can give rise to the expansion of graphene oxide. Based on such weakly oxidized graphite, the high degree of exfoliation of and expansion has been achieved with physical approaches, which significantly increased the production efficiency and decreased the energy consumption.

Since 2011, the Sixth Element (Changzhou) Materials Technology Co., Ltd has been devoted to the large-scale manufacture of graphene based power materials. We have been continuously improving the design of production equipment, developing fully-automated synthesis system to increase the efficiency and quality of the production. More importantly, the cutting-edge research and development has been focused on the innovation in the weak oxidation technique and in the downstream application of graphene materials. Currently, the capacity of graphene materials in Sixth Element reaches 100 tons per year and the materials have shown promising use in coatings, composite materials, lithium ion batteries, and super-capacitors.

References:

[1] Park S, Ruoff RS. Nat Nanotechnol 2010; 5(4):217-24.

[2] Gogotsi Y. J Phys ChemLett 2011; 2(19):2509–2510.

[3] Long Zhang, Yongsheng Chen. Carbon 2009, 47, 3365-3380

[4] D. A. Dikin , S. Stankovich , E. J. Zimney , R. D. Piner , G. H. B. Dommett , G. Evmenenko , S. T. Nguyen , R. S. Ruoff. Nature 2007, 448, 457

[5] H. Zhang, X. J. Lv, Y. M. Li, Y. Wang, J. H. Li, ACS Nano, 2010,4, 380–386.