Page 30 - PR 2014 2016 10 Materials and Nanotechnology

306 Materials and Nanotechnology | Progress Report

Magnetic, Electric and common shortcomings. With this perspective,
Nuclear Materials supercapacitors have been acknowledged as

one of the promising devices in the energy
storage industry and fast progress has been
Supercapacitors – Photoelectric cells - made in the development of fundamental
Batteries and applied aspects of these energy devices.

The increasing demand on sustainable ener- In this brief progress report, we describe our
gy impelled the development of alternative recent research investigation on the prepa-
energy sources with high power and energy ration of various nanostructured graphene
densities. Supercapacitors, batteries and fuel and zinc oxide electrode materials and the
cells are typical non-conventional energy stor- performances of symmetric supercapacitors.
age devices which are based on chemical to Vacuum thermal reduction of graphene oxide
electrical energy conversion. These devices find has been carried out in the group of Super-
extensive applications in consumer electronics capacitors, Batteries and Photovoltaic cells.
ranging from mobile phones, laptops, digital Graphene oxide nanocomposites have also
cameras, emergency doors and hybrid vehicles been successfully used to prepare electrical
etc. In all these devices, the chemical energy double layer supercapacitors. Internal series
is converted into electrical energy by means resistance has been diminished with the ther-
of electrochemical reactions. In fuel cells, as mal reduction procedure. A post-doctorate
long as the fuel is fed, the electrical energy research project has been carried out on this
will be obtained and in batteries, the stored subject, which resulted in the publication of
energy would be drawn on demand, requiring papers and a patent deposit. A master degree
a recharging time afterwards. Electrochemi- on this subject has been finalized and another
cal supercapacitor is a typical storage device patent is being written. A doctorate project
which possesses high specific capacitance, has also been implemented in the promising
high power density and long cycle life and can area of palladium incorporation on graphene
be used in combination with batteries or fuel nanomaterials and also three master degree
cells to meet the start-up at high power density. investigation studies in carbon supercapacitors.
Measurements techniques have been applied
Electrical double layer capacitors, pseudo-ca- to estimate the specific capacitance of the
pacitors and asymmetric supercapacitors are electrode nanomaterials. Cyclic voltammetry
the three types of supercapacitors, classified on and galvanostatic cycling have been employed
the electrochemical responses and electrodes with success for this purpose. Efforts have also
design. Double layer devices use high surface been made to increase the specific capacitance
area materials such as activated carbons or of the electrode nanomaterials. In the field of
derivatives for providing high electrostatic dou- batteries, a doctorate has been approved and
ble-layer capacitance. The separation of charge another is being finalized. Progress has also
obtained in the Helmholtz double-layer device been made in the field of photovoltaic cell with
occurs at the interface between the conductive the implementation of an automatic research
electrode and the electrolyte. The advantages facility for preparing zinc oxide nanomaterial
of these electrochemical devices include high for energy conversion devices. Zinc oxide thin
power density and good cycling life while low films have been deposited using a Successive
energy density and low cell voltage are the Ionic Layer Adsorption and Reaction (SILAR)

Instituto de Pesquisas Energéticas e Nucleares