ISSN 1070-4272, Russian Journal of Applied Chemistry, 2016, Vol. 89, No. 5, pp. 739í745. © Pleiades Publishing, Ltd., 2016.
Original Russian Text © A.A. Shibaev, S.I. Yusin, E.A. Maksimovskii, A.V. Ukhina, A.G. Bannov, 2016, published in Zhurnal Prikladnoi Khimii, 2016, Vol. 89,
No. 5, pp. 605í611.
Chemical Treatment of Graphite Nanoplatelets
and Their Use in Supercapacitors
A. A. Shibaev
, S. I. Yusin
, E. A. Maksimovskii
, A. V. Ukhina
, and A. G. Bannov
Novosibirsk State Technical University, pr. Karla Marksa 20, Novosibirsk, 630073 Russia
* e-mail: Bannov.email@example.com
Institute of Solid State Chemistry and Mechanochemistry, Siberian Branch, Russian Academy of Sciences,
ul. Kutateladze 18, Novosibirsk, 630128 Russia
Nikolaev Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences,
pr. Lavrentieva 3, Novosibirsk, 630090 Russia
Novosibirsk State University, ul. Pirogova 2, Novosibirsk, 630090 Russia
Received April 14, 2016
Abstract—Graphite nanoplatelets treated with nitric acid of different concentrations were studied. The initial
graphite nanoplatelets were prepared by ultrasonication of exfoliated graphite. The samples were examined by
scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, and FTIR and Raman
spectroscopy and were tested as electrode materials for supercapacitors.
Graphite nanoplatelets (GNPs) are characterized by
very small thickness relative to the lateral dimensions.
The nanoplatelet thickness varies from 2 to 150 nm .
Graphite nanoplatelets can be prepared by ultrasonication
of exfoliated graphite in various solvents  and by
chemical reduction of graphite oxide nanoplatelets
. An interesting approach to the GNP preparation
was suggested by Mukherjee et al. : exfoliation of
graphite in oleum.
Graphite nanoplatelets can be used as ﬁ llers of
polymeric composites  and as components of catalysts
for oxidation of methanol  and ethanol . Another
important application of graphite nanoplatelets is their
use in supercapacitors [8, 9].
The starting material for GNP preparation, exfoliated
graphite, contains a low amount of surface functional
groups. Therefore, the electrochemical characteristics
of such material, important in fabrication of electrodes
for supercapacitors, are poor. However, GNP treatment
in nitric acid increases the content of functional groups,
which should improve the electrochemical characteris-
tics. The effect of chemical treatment of graphite nano-
platelets on the electrochemical characteristics of the
material has not been studied systematically. Therefore,
studies in this ﬁ eld are very important.
This study deals with the chemical treatment of
graphite nanoplatelets in nitric acid solutions. The
inﬂ uence of the nitric acid concentration on the speciﬁ c
capacitance of the material was examined.
The initial GNP material was a black powder
with a bulk density of 0.0169 g cm
. These graphite
nanoplatelets were prepared by ultrasonication
of exfoliated graphite (EG) in dimethyl sulfoxide
[chemically pure grade, TU (Technical Speciﬁ cation)
6-09-3818–89]. A glass vessel was charged with 50 mL
of the solvent and 0.25 g of EG. After that, the vessel
with the solvent and EG was placed in a UZV-3/200-
TN-RELTEK ultrasonic bath. The ultrasonication was
performed for 30 min at a frequency of 22 kHz. After the
treatment, the solvent was evaporated for 3 h until it was
removed from the sample completely.
To increase the speciﬁ c capacitance of graphite
nanoplatelets in supercapacitors, they were treated