nanomat-2019-keynote

2 / 4

Nano Research & Applications
ISSN: 2471-9838
January 28-29, 2019
Barcelona, Spain
Nanomat 2019
Page 16
18th Edition of International Conference on
Emerging Trends in
Materials Science and
Nanotechnology
T his contribution deals with the fabrication of devices based
on graphene based nanomaterials using dynamic spray gun
deposition method implemented through roll-to-roll. We used
this technique to fabricate supercapacitors, flexible memories
and conformable electro-magnetic shielding (EMS) layers.
In the first case we exploited the nanostructuration mixtures
of graphene and carbon nanotubes to achieve electrodes for
supercapacitors (Fig.1). Indeed the carbon nanotubes (Multi-
Walled Carbon Nanotubes that are metallic and so conductive)
are used as sort of spacers to avoid the restacking of graphene.
Thanks to that we can exploit the huge surface of graphene to
store charges and at the same time we create channels between
the layers allowing the rapid charge and discharge of the device.
The use of high quality graphene (<5 layers) and MWCNTs, with
a diameter of around 20 nm also improve the conductivity for
the electrodes and allows us in obtaining an impressive specific
power value of around 100 kW/kg using an industrially suitable
technique not only a lab based one. In order to increase the
energy storagewe have used ionic liquidwhich aremore viscous,
having large charges. In this case as spacers we have used
carbon nanofibers with larger diameters (10 nm -100 nm). The
spray-gun deposition method has also been implemented in the
fabrication of graphene oxide and carbon nanofibers oxidized
basedmemories. In this casewe spray nanomaterial water based
suspensions on a flexible layer which are previously metallized.
The total thickness is around 100 nm. After contacting the top
withmetallic contacts we are able to achieve flexible non-volatile
memories by simply applying a bias (<3V). These memories
showbipolar behavior and have been cycled 10000 times (Fig. 2).
They constitute one of the first examples of information storage
devices that can be fabricated using a roll-to-roll implementable
method. These devices can open new horizons in the integration
of memories for example in RFID tags or in packages. Finally,
we have achieved EMS architectures using nanostructuration
of graphene, MWCNTs and carbon nanofibers between polymer
layers in order to exploit the Maxwell-Wagner-Sillars effect to
absorb X-band frequencies. Thanks to this nanostructuration
as we are able to trap the charges in sort of micro-capacitors
created in the layers. This is a real breakthrough considering
that usually heavy metal based layers are used and that in this
case mm based conformable layers can be obtained opening
the route for new kinds of applications. Also in this case the
fabrication will be implemented by roll-to-roll fabrication.
During the presentation we will show all the details on the first
characterization of devices and we will also show perspectives
for other potential fields of applications.
Recent Publications
1. P Bondavalli, C Delfaure, P Legagneux and D Pribat
(2013) Supercapacitor electrode based on mixtures of
graphite and carbon nanotubes deposited using a new
dynamic air-brush deposition technique. Journal of The
Electrochemical Society 60(4):A1-A6.
2. P Bondavalli, D Pribat, C Delfaure, P Legagneux, L
Baraton, L Gorintin and J P Schnell (2012) Non-faradic
carbon nanotubes based supercapacitors:state of the
art. Eur. Phys. J. Appl. Phys. 60:10401.
Biography
Paolo Bondavalli is incharge of the nanomaterial transverse topic at Thales
Research and Technology. In the last years, he has been the first author of
several scientific papers dealing with CNTFET based sensors, supercapac-
itors and several patents dealing with gas sensors, thermal management
through CNTs, nanomaterials deposition, supercapacitors and memristors
like structures. Presently, his work is focused on the development of new
materials (e.g., graphene, CNTs and nanowires) for the new generation of
electronics devices and for energy storage applications and memristors.
He is EU expert and Vice-Chairman for Marie Curie Fellowships (EIF, IIF,
OIF, CIG, IRSES), NMP and ICT panel for the French National Research
Agency (ANR), EDA, Eureka and reviewer for IOP, ACS, IEEE, ECS, Elsevier,
EPJ B, Bentham, Taylor & Francis, etc. During the last five years he also
participated as coordinator in several EU projects (concerning MEMS, MO-
EMS, CNTs, graphene, spintronics) and ANR projects. He is involved in the
Graphene Flagship initiative.
Spray-gun deposition method for nanomaterials
and its application in different high-impact field
Paolo Bondavalli
Thales Research and Technology, France
Paolo Bondavalli, Nano Res Appl 2019, Volume 5
DOI: 10.21767/2471-9838-C1-029