645 ISSN 2070-2051, Protection of Metals and Physical Chemistry of Surfaces, 2016, Vol. 52, No. 4, pp. 645–652. © Pleiades Publishing, Ltd., 2016. Original Russian Text © A.G. Bannov, S.I. Yusin, A.A. Timofeeva, K.D. Dyukova, A.V. Ukhina, E.A. Maksimovskii, M.V. Popov, 2016, published in Fizikokhimiya Poverkhnosti i Zashchita Materialov, 2016, Vol. 52, No. 4, pp. 399–406. Synthesis of Exfoliated Graphite and Its Use as an Electrode in Supercapacitors A. G. Bannov a, *, S. I. Yusin a, c , A. A. Timofeeva a , K. D. Dyukova a , A. V. Ukhina c , E. A. Maksimovskii b , and M. V. Popov a a Novosibirsk State Technical University, Novosibirsk, 630092 Russia b Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences, Novosibirsk, 630090 Russia c Institute of Chemistry of Solid State and Mechanochemistry, Siberian Branch, Russian Academy of Sciences, Novosibirsk, 630092 Russia *e-mail: bannov.alexander@gmail.com Received February 20, 2015 Abstract—In this work, the effect of the synthesis conditions on exfoliated graphite and its properties was investigated. Exfoliated graphite was obtained via thermal reduction of graphite oxide at temperatures of 250– 350°С. The influence of the synthesis conditions (temperature and heating rate) on the properties of exfoli- ated graphite (product yield, bulk density, specific surface area, specific capacitance and others) was deter- mined via direct experimental design method. The ability to use exfoliated graphite in supercapacitors was determined on the basis of the specific capacitance data. The highest specific capacitance of exfoliated graph- ite was found to be 129 F/g. DOI: 10.1134/S2070205116020040 INTRODUCTION Since K.S. Novoselov and A.K. Geim won the Nobel Prize for Physics, increasing attention of the scientific community has been focused on synthesis and investigation of the properties of graphene and graphene-like materials, such as graphene [1], graph- ite nanoplatelets [2], graphene oxide [3], graphite oxide [4] and many others, as well as modifications thereof. Exfoliated (or exfoliated) graphite [5] can be attributed to this group. This material is widely used as a sorbent [6], sealing material [7], flame retardant material component [8], and filler for nanocomposites [9]. It seems to be promising as an electrode material in supercapacitors, as well [10, 11]. A significant contribution to the development of syn- thesis methods and investigation of the properties of exfo- liated graphite in Russia was made by Prof. V.V. Avdeev et al. [12, 13]. In most cases, exfoliated graphite is obtained from intercalated graphites with the use of rapid heating (thermal shock). It is worth singling out synthesis of exfoliated graphite from graphite oxide (GO) [14], because the number of the articles devoted to this method is supe- rior to others. In particular, exfoliated graphite can be obtained from GO via microwave radiation [15], ther- mal reduction of GO [16] and ultrasonication in com- bination with chemical reduction [17]. Here, thermal reduction of GO is the simplest and attractive method for this purpose [16, 18, 19]. In the foreign literature, thermal reduction of graph- ite oxide is actually associated with a synthesis of the reduced graphite oxide [20]. This technique is used for synthesis of graphite and graphene-like materials [21]. Despite the fact that work in this area are being car- ried out by leading scientific groups throughout the world, almost all publications have been focused on the investigation of properties of the most successful samples without a detailed study of the effect of the synthesis conditions on the properties of the exfoliated graphite. At the same time, understanding the rela- tionship between the synthesis conditions of exfoliated graphite and its properties would help to optimize syn- thesis and attain the required characteristics of the material. This task is of great importance, and its solu- tion will extend the range of applications of exfoliated graphite. This work is aimed at studying the conditions of syn- thesis of exfoliated graphite from graphite oxide via ther- mal reduction of GO on the properties of the obtained material. The optimum synthesis conditions are deter- mined, and the prospects of the use of exfoliated graphite as electrode material in supercapacitors are estimated. EXPERIMENTAL Synthesis of Exfoliated Graphite Exfoliated graphite was synthesized from various graphite oxide samples. GO was prepared using the NEW SUBSTANCES, MATERIALS, AND COATINGS