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“Study of Graphene based coin cell-type
symmetric supercapacitor”BY
Mr. Girish Sambhaji GundM. Sc.
UNDER THE GUIDANCE OF
Prof. C. D. Lokhande
M. Sc., Ph. D.
THIN FILM PHYSICS LABORATORY,
DEPARTMENT OF PHYSICS, SHIVAJI UNIVERSITY,
KOLHAPUR - 416 004 (INDIA)
2013
Objectives
Introduction to supercapacitor
Why graphene?
Graphene thin films by screen printing
Characterization of graphene thin films
Device fabrication and performance evaluation of coin cell-type
symmetric device based on graphene thin films in non-aqueous
electrolyte
Demonstration
Conclusions
Plan of Presentation
Objectives
To develop efficient, small size and low cost energy storage
device in order to employ in portable electronics.
The use of carbon based electrode material in supercapacitor as its
abundant in nature with the intention to replace toxic and high cost
RuO2 and IrO2.
Supercapacitors
A Supercapacitor is an electrochemical capacitor that has an high
energy density and capacitance compare to ordinary capacitor.
APPLICATIONS
1. Power Electronics
2. Telecommunication
Devices
3. Satellites
4. Standby Power Systems
5. Electrical Hybrid Vehicles
ADVANTAGES OVER BATTERIES
1. Very high rates of charge and
discharge
2. Little degradation over hundreds of
thousands of cycles
3. Good reversibility
4. Low toxicity of materials used.
5. High cycle efficiency (95% or more)
Types of Supercapacitor
Electric Double layer capacitors (EDLCs): The storage
mechanism involves charge separation at electrode – electrolyte interface
(carbon based).
Pseudocapacitors: Pseudocapacitance arises from reversible Faradaic
reactions occurring at the electrode, and is denoted as ‘pseudo’-capacitance
in order to differentiate it from electrostatic capacitance.
Requirements for Supercapacitive electrode:
High conductivity
Large surface area
Good chemical stability
Good reversibility
Materials used for supercapacitors
Carbon
Transition Metal Oxides
Conducting Polymers (Polyaniline, Polypyrrole etc)
Why Graphene?
Among the all carbon allotropes, graphene has an attractive view because
of the,
High electrical conductivity
High specific surface area
High mechanical strength
High chemical stability
Reduction of graphite oxide to graphene:
Graphite Oxide was synthesized through Hummers method
Graphite oxide (1 mg ml-1) with water
Addition of 1ml of HH in 50 ml GO solution
Ultra-sonication for 30 minutes
Hydrothermal treatment at 180 C for 12 hr
Graphene precipitated
Filtered and washed
Dried at 70 C for 24 hr
Centrifuged at 16,000 rpm and solution is separated
Graphene thin film through Screen printing
method :
Paste = Graphene (90%) + Tr-X-100 (10%)
Squeegee blade
Graphene thin film
Screen
Structural and Morphological measurements:
BET Study:
Fabrication of coin cell-type symmetric supercapacitor
device:
Electrochemical measurements:
81 F g-1
S.E. = 24.5 Whkg-1
S.P. = 10 kWkg-1
ESR = 85.2 Ω cm-2
Rct = 121.3 Ω cm-2
36 F g-1
Conclusions
Successfully fabricated coin cell-type symmetric supercapacitor
based on graphene thin film with economical construction route.
Electrochemical measurements exhibits boost up performance of
graphene based coin cell-type symmetric supercapacitor device,
like specific capacitance of 81 Fg-1, specific energy of 24.5 Whkg-1
and specific power of 10 kWkg-1.
The obtained performance can be further enhanced through using
composite electrode material of graphene and metal oxides or
polymers or both.
Department of Physics, Shivaji University, Kolhapur.
DAE-BRNS, Mumbai.
Acknowledgement