1. Nitrogen Enriched Carbon Coated Chemically
Modified Graphene Scaffold For Capacitive
Energy Storage
By:
Amerjit
2. Graphene
Super Capacitor
Graphene Oxide
Objectives
Experimental Procedure
Characterization and Results
Conclusions
3. Graphene is a single tightly packed layer of
carbon atoms that are bonded together in a
hexagonal honeycomb lattice.
Layers of Graphene stacked on top of each
other form graphite , with an inter planar
spacing of 0.335 nano metres.
The lightest material known (with 1 square
meter coming in at around 0.77 milligrams),
The strongest compound discovered
(between 100-300 times stronger than steel)
The best conductor of electricity known
4. PROPERTY RANGE
Theoretical specific surface area 2630 m2 g-1
Young’s modulus 1 T pa
Fracture strength 120 M pa
Carrier mobility at room temperature 10,000 cm2 V-1 S-1
Optical transmittance 97.7%
Electrical conductivity 5000 W m-1 K-1
Specific capacity 80 mF cm-2
Specific capacitance 550 F g-1
5.
6. Graphene has substantially more
relative surface area.
Thus, as a super capacitor material
it will be better at storing
electrostatic charge.
Material made up of one single
atomic layer, it is lighter.
Ecologically friendly, unlike most
other forms of energy storage.
7. Structurally, GO can be visualized as a graphene sheet with its
basal plane decorated by oxygen-containing groups.
Due to high affinity to water molecules by these groups, GO is
hydrophilic and can be dissolved in water.
The solubility in water makes the deposition of the thin films
of the GO straightforward.
GO is a poor conductor but its chemical treatment by light,
heat, or chemical reduction can restore most properties of the
famed pristine graphene.
8.
9. The modified Hummer’s hydrothermal method was employed to
prepare reduced Graphene oxide using the exfoliated graphite.
Chemically modify reduced Graphene oxide by enriching with
nitrogen and coating with carbon sources.
Characterize the different types of samples for different
properties such as morphology, conductance, electrochemical
properties, absorbance, and zeta potential.
10. Exfoliated Graphite(EG): Carbon content=99%,
Apparent Density=0.0025g/cc
Graphite Nano Pellets(GNP): Carbon content=99%,
Apparent Density=0.06g/cc
H2SO4: As a medium for oxidizer
KMnO4: As an oxidizer
H2O2: To remove excess KMnO4
HCl: To remove the manganese salts
DI water: For dilution and neutralizing
MATERIALS AND THEIR PROPERTIES:
16. FE-SEM images of (a) GO (b) RGOD8(c) RGODE8 (d) RGOD20 (e) RGODE20
17. 1) GO Sample was gold sputtered as it was least conductive, and
overall image showed that it has a layered structure.
2) RGOD sample had carbon spheres due to D-glucose which was
used as carbon source for coating.
3) RGODE samples had less carbon spheres and more porous
structure due to addition of nitrogen source EDA.
4) Time of reduction of GO is directly proportional to porous
morphology and inversely proportional to the amount of
carbon spheres.
18. Elemental SEM Mapping was done for primary elemental analysis and data
obtained is not accurate for Nitrogen content in the samples.
• GO:
21. GO mapping showed less carbon content due to impurities
during synthesis.
Mapping confirmed that RGODE had less oxygen content
as compared to RGOD and more carbon content.
With increase in time of reduction, the carbon content
increases in case of RGODE whereas in RGOD oxygen
content was more.
22. All the UV-Vis absorption spectra were conducted on a Perkin-Elmer
Lambda 950 UV-Vis-NIR spectrophotometer.
200 400 600 800 1000
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
0.50
0.55
0.60
0.65
0.70
0.75
0.80
0.85
0.90
0.95
1.00
Absorbance(A)
Wavelength(nm)
RGODE20
RGOD20
RGODE8
RGOD8
GO
23. 1. The quality of results depends on the dispersion of particles and viscous
nature of the solution.
2. The noise in the graph is directly proportional to the concentration of
the solute in the solution.
3. The peak of RGO shifted to higher values with increase in time of
reduction.
4. The absorbance of RGO was increased with respect to base material on
addition of ‘C’ and ‘N’.
24. Cyclic Voltammetry is used
to determine the
electrochemical properties
of electrodes using three
electrode system.RGO is
used as working electrode,
Pt is used as the counter
electrode and Ag/AgCl is
the reference electrode.1M
of H2SO4 is used as the
electrolyte in aqueous
system.
-1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8
-0.7
-0.6
-0.5
-0.4
-0.3
-0.2
-0.1
0.0
0.1
0.2
0.3
0.4
Current
(A)
Potential (V)
0.01
0.1
0.05
Scan Rate(V/s)
25.
26. 1) Current variation was studied at different scan rates, from which
capacitance and specific capacitance was calculated.
2) As scan rate increases the specific capacitance was found to
decrease because the ion migration from the electrode reduces.
3) The RGOED20 sample was observed to have higher value of
specific capacitance than other conventional electrodes.
27. • Modified hummer’s method was employed to generate highly oxidized Graphene
oxide. Reduced Graphene oxide (RGO) was prepared by hydrothermal method .GO is
enriched with nitrogen which is found to improve the capacitive property.
• The content of oxygen was significantly reduced as the reduction duration was
increased. The comparison was done with two samples having reduction time 8 Hrs.
and 20 Hrs. respectively. It was found that the oxygen content for the latter was 50%
lesser than the former.
28. • The SEM mapping results showed the distribution of elements mainly carbon, oxygen
and nitrogen in the respective samples. The concentration of oxygen was less in the
samples containing Nitrogen.
• Characterization techniques showed that nitrogen enriched carbon coated RGO had
higher porosity and lower density which is a prerequisite for electrode material.
• Quality of RGO improves and Nitrogen enrichment decreases with increase in time of
reduction.
• N’ enriched RGO was found to have higher value of specific capacitance
29. The Carbon Spheres observed in the FESEM Analysis showed that this
technique of Carbon coating with D-Glucose can result in formation of such
compounds.
The RGO with ‘N’ and ‘C’ content can be effectively used as electrode
material for capacitive energy storage.
The Automobile and Telecom industry needs a new source for battery, i.e.
the Super capacitors which can be interpreted from this type of materials to
give high efficiency and longer life as compared to conventional materials.
