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University of Salerno
Graphene for supercapacitor application
Maria Sarno
Prof. Maria Sarno
Professor of Chemical Engineering
Director of NANO_MATES (Research Centre for NANOMAterials and nanoTEchnology at Salerno Univerity).
«Measurement of the quantum capacitance of graphene»
Xia J. et al., Nat Nanotechnol, 2009.
«Graphene-Based Supercapacitor with an Ultrahigh Energy Density»
Liu C. et al., J. NANO LETT, 2010.
«Ultrathin Planar Graphene Supercapacitor»
Yoo J. et al., NANO LETT, 2011.
«Electrochemical properties for high surface area and improved electrical conductivity of platium-embedded porous carbon nanofibers»
An G.-H. et al., J POWER SOURCES, 2012.
University of Salerno
Core – shell graphene coated FeCo
nanoparticles (GFeCo)
M. Sarno et al., Electrochemical Applications of Magnetic Core–Shell Graphene-Coated FeCo
Nanoparticles, Ind. Eng. Chem. Res., 2016, 55 (11), pp 3157–3166.
.
«Novel Cd-doped Co/C nanoparticles for Electrochemical Supercapacitors»
Barakat et al., MATER LETT, 2013.
«Silver nanoparticles decorated on a three-dimensional graphene scaffold for electrochemical applications»
Bello A. et al., J PHYS. CHEM. SOLIDS, 2014.
«Nitrogen-doped, FeNi alloy nanoparticle-decorated graphene as an efficient and electrode for electrochemical supercapacitors in acid
medium»
El-Deen et al., NANOSCALE RES LETT, 2015.
Graphene & Metal/Graphene composites for supercapacitors:
STATE OF ART
“Electrochemical Applications of Magnetic Core–Shell
Graphene-Coated FeCo Nanoparticles,
Maria Sarno et al., Ind. Eng. Chem.
Res., 2016”.
3 4 5 60
20
40
60
80
100
120
140
160
Co
un
ts
Diameter [nm]
GCMNPN2
Nanoparticles Results & DiscussionSYNTHESIS AND CHARACTERIZATION
1500 2000 2500
Inte
nsity (
a.u
.)
Wavenumber (cm-1)
D
G
2D
20 40 60 80
Inte
nsity (
a.u
.)
2Q°
(110)
(200) (211)
f
Core shell graphene coated FeCo nanoparticles have been prepared by a catalytic chemical vapor
deposition (CCVD) of methane on a FeCo catalyst in the channels of an alumina support.
X Ray Diffraction Pattern
Raman Spectrum
TEM images
1-2 graphene
layers
5 nm
2θθθθ °
Raman Shift cm-1
Galvanostatic Charge/Discharge Tests
C= 367,2 F/g at 0,9 A/g
University of Salerno
Graphene based Electrode Materials
M. Sarno et al., Supercritical CO2 processing to improve the electrochemical
properties of graphene oxide, J. of Supercritical Fluids 2016, 118, 119-127.
About SC-CO2 PROCESS FOR GRAPHENE-based SUPERCAPACITORS ELECTRODEs:
«Preparation of graphene oxide/polyaniline nanocomposite with assistance of supercritical carbon dioxide for supercapacitor
electrodes» G. Xu et al., Ind. Eng. Chem. Res. 2012
«Supercritical CO2 processing to improve the electrochemical properties of graphene oxide»
M. Sarno et al., J. of Supercritical Fluids 2016
SC-CO2 PROCESS FOR GRAPHENE-based SUPERCAPACITORS ELECTRODEs: STATE OF ART
Characterization
Mesoporous reduced graphene structures at different oxidation levels, have been obtained by SC-CO2 assisted process different durations
up to 24 h. It is investigated the effect of SC-CO2 processing on GO to produce a mesoporous reduced and exfoliated graphene structure
with high surface area and excellent electrochemical performance.
f
GO GO rGO-SC 24h
Typical contributions from• hydroxyl (C-OH),• ketonic species (C-O), • carboxyl (COOH), • sp2-hybridized C=C (in-plane vibrations), • epoxide (C-O-C) and • various C=O and C-O containing chemical species such as lactol, peroxide,
dioxolane, anhydride and cyclic ether
C=O
COOH
C-O-C
C-O-C
C=CC=C
OH of carboxyl group
Electrochemical characterization 1/2
0 100 200 300 400 500 6000,0
0,2
0,4
0,6
0,8
1,0 4 A/g
1,7 A/g
0,5 A/g
Vo
ltag
e /
V
Time / s
0 100 200 300 400 500 6000,0
0,2
0,4
0,6
0,8
1,0 4,5 A/g
1,7 A/g
1 A/g
Vo
ltag
e /
V
Time / s
ab
c
CYCLIC VOLTAMMETRY (a) GALVANOSTATIC CURVES (b, c)
rGO-SC 3h
rGO-SC 24h
At the same current density (1.7 A/g) the specific
capacitance of rGO-SC 24h (253 F/g) results about
three times larger than the one exhibited by rGO-
SC 3h (86 F/g).
0,0 0,2 0,4 0,6 0,8 1,0-30
-20
-10
0
10
20
30 GO
GO-SC3h
GO-SC24h
Cu
rren
t (A
/g)
Potential (V)
0 2 4 6 8 10 12 14 16
50
100
150
200
250
GO-SC 24 h
GO-SC 3h
Sp
ec
ific
Cap
acit
an
ce
/ F
g-1
Current density / Ag-10,0 5,0x10
21,0x10
31,5x10
32,0x10
32,5x10
30
20
40
60
80
100
GO-SC 24h
GO-SC 3h
Cap
acit
an
ce r
ete
nti
on
/ %
Cycles
Electrochemical characterization 2/2
Graphene based materials to realize:
a Novel Compact Supercapacitors
M. Sarno et al., SC-CO2-assisted process for a high energy density aerogel supercapacitor:
The effect of GO loading, Nanotechnology 2017, 28(20).
Electrodes with PVDF-HFP Poly(vinylidene fluoride-co-hexafluoropropylene) as electrode binder:
“ Supercapacitors from Activated Carbon Derived from Banana Fibers
Subramanian V, et al., J. Phys. Chem. C, 2007”.
Supercapacitors Devices with PVDF-HFP in gel polymer electrolyte:
“Electrochemical redox supercapacitors using PVdF-HFP based gel electrolytes and polypyrrole as conducting polymer
electrode Tripathi et al, Solid State Ionics, 2006 ”.
“Studies on redox supercapacitor using electrochemically synthesized polypyrrole as electrode material using blend
polymer gel electrolyte Tripathi et al., Indian J. Pure Appl. Phys, 2013”.
“High-performance flexible solid-state supercapacitors based on MnO2-decorated nanocarbon electrodes
Gao Y, et al., RSC Adv. 2013 “
“Ionic Liquid Directed Mesoporous Carbon Nanoflakes as an Effiencient Electrode material
Kong L and Chen W Sci. Rep. 2015”
Others Supercapacitors Devices :
«All-solid-state asymmetric supercapacitor based on reduced graphene oxide/carbon nanotube and carbon fiber
paper/polypyrrole electrodes Yang C, et al., J. Mater. Chem. A, 2014»
Compact Supercapcitor Devices: STATE OF ART
New Compact Supercapacitor Device
Acetone
GO
Sonication
Ethanol
Sonicated nanoparticles
PVDF-HFP
Acetone
<
Materials:
• GO prepared with Hummers’ method modified
• Poly-vinylidene fluoride-co-hexafluoropropylene (PVDF-HFP) immersed in 1-
ethyl-3-methylimidazolium tetrafluoroborate, (EMIM BF4).
• PVDF-HFP_GO nanocomposite aerogel immersed in (EMIM BF4).
<
SEM images
PVDF_HFP
bd
c
Electrolyte Uptake (E u)
0 5 10 15 20
0
200
400
600
800
PVDF-HFP
PVDF-HFP_GO10
PVDF-HFP_GO30
PVDF-HFP_GO60
PVDF-HFP_GO90
Ele
ctr
oly
te u
pta
ke (
%)
Time (min)
0 130 260 390 520 650 780 910 1040 1170
Time (min)
0 20 40 60 80 100
80
82
84
86
Po
ros
ity
(%
)
GO amount in aerogel (w/w)
Porous volume
E u = (Ww − Wd)/ Wd × 100%
PVDF_HFP_GO30
PVDF_HFP_GO60 PVDF_HFP_GO90
a
b
c
Electrochemical Characterizations
2000 2100 2200 2300 2400 2500 2600 2700
Po
ten
tia
l (V
)
Time (sec)
0
2
-2
-2 -1 0 1 2-3x10
1
-2x101
-1x101
0
1x101
2x101
3x101
50 mV/sec
PVDF-HFP_GO10_SC
PVDF-HFP_GO60_SC
PVDF-HFP_GO90_SC
Cu
rren
t (A
/g)
Potential (V)-2 -1 0 1 2
-5x101
-4x101
-3x101
-2x101
-1x101
0
1x101
2x101
3x101
4x101
5x101
PVDF-HFP_GO60_SC
10 mV/sec
20 mV/sec
50 mV/sec
100 mV/sec
150 mV/sec
Cu
rre
nt
(A/g
)
Potential (V)
0 200 400 600 800
6 A/g
4 A/g
2 A/g
1 A/g
0,5 A/g
Po
ten
tial
(V)
Time (sec)
0
2
-2
0 2 4 60
10
20
30
40
50
60
Cap
ac
ita
nc
e (
F/g
)
Current density (A/g)
55 60 65 70 75 80 85 90 95 1000
Po
we
r d
en
sit
y (
W/k
g)
Energy density (Wh/kg)
0 2 4 6 8 100
20
40
60
80
100
En
erg
y d
en
sit
y (
Wh
/kg
)
Current density (A/g)
0,0 5,0x104
1,0x105
0
20
40
60
80
100
Cap
acit
an
ce r
ete
nti
on
/ %
Cycles
1 2 3 4 5 6 7 8 9 100
-2
-4
-6
-8
-10
Z''
(o
hm
)
Z' (ohm)
0 100 200 300 400 5000
-100
-200
-300
-400
-500
PVDF-HFP_GO60
PVDF-HFP_GO60 after 5*104 cycles
Z''
(o
hm
)
Z' (ohm)
CV Curves GDC Tests
Ragone Plot
Specific Capacitance Vs Current
density
Capacitance retentetion
Cyclic voltammogram (CV) of PVDF-HFP_GO10, PVDF-HFP_GO60 and PVDF-HFP_GO90 at 50 mV/s between -2 V and 2V
(a). CV of PVDF-HFP_GO60 at different scan rate between -2 V and 2V (b). Galvanostatic charge-discharge (GCD) curves
of PVDF-HFP_GO60 at different current density between -2 V and 2V (c). Specific capacitance at different current
density (d). Ragone plot. Insert showing energy density as a function of current density (e). Cycling life test of PVDF-
HFP_GO60 at 6A/g (f). Nyquist plot before and after GCD cycling (g).
a b
c
d
eg
f
C= 83 F/g
E=79.2 Wh/kg
P= 234 W/Kgat the current density of 0.5 A/g
In summary
• Controlled size, structure, and morphology core−shell 1−2 layer graphene-coated metallic
nanoparticles have been prepared by methane CCVD at atmospheric pressure. Electrochemical
tests show ideal capacity behavior, efficient energy storage, and excellent cycling stability. Such
high supercapacitor performance can be attributed to the high electric double-layer contribution
ensured by the micro-mesoporosity, with a high effective surface area and excellent electrical
transport of the conductive network.
• Feasibility of a SC-CO2 assisted process to reduce and exfoliate GO powders, obtaining porous and
three-dimensional architectures formed by curved graphene sheets.
• Supercapacitors have been assembles in a sandwich design formed by three porous layers.
Other Materials
ELECTRODES
� MoS2
� MoS2/FLG
� MoS2/MoO2/FLG
� Carbon nanotubes
� Flexible Supercapacitors with others nanomaterials, such as
� :• Fe3O4
• MoS2
• NiMoS• Ag/graphene
• RuO2/Os
• MoS2/Fe3O4• ….
Eng. Carmela Scudieri
Eng. Marcello Casa
Eng. Claudia Cirillo
Eng. Mariagrazia Iuliano
Eng. Waleed Abdalglil Mustafa
Eng. Eleonora Ponticorvo
Eng. Davide Scarpa
Eng. Domenico Spina
Eng. Alfonso Troisi
Eng. Gianluca Viscusi
Thank you for your attention
Acknowledgement
Prof. Paolo Ciambelli
Prof. Ernesto Reverchon and his research
group
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