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Three-dimensional Surface Nanostructures for
Energy Storage Applications
By
Ranjith Vellacheri1,2, Zhibing Zhan1,2, Huaping Zhao1,2 & Yong Lei1,2*
1 Fachgebiet 3DNanostrukturierung, Institut für Physik & Zentrum für Mikro- und Nanotechnologien (ZIK MacroNano), Technische Universität Ilmenau, 98693 Ilmenau
2 Institut für Material Physik, Westfälische Wilhelms-Universität Münster,
48149 Münster
* Email- [email protected]
Outline • Supercapacitor (structure, applications etc.)
• Electrode fabrication- conventional method Vs. template based
approach
• Preparation and characterisation of MnO2 and PEDOT nanoarrays
• Conclusion
Supercapacitors or Electrochemical capacitors or Ultracapacitors are electrochemical energy storage devices which store more energy than that of conventional capacitors (yet less than that of batteries) and can deliver all the stored energy more quickly than a battery. Salient features • Fast charge-discharge • High cycle-life, • More safe Applications Energy storage in electric vehicles (EV), hybrid electric vehicles (HEV) and micro electromechanical devices (MEMS)
Supercapacitors
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Basic structure of supercapacitor
Conventinal method for electrode fabrication
Coating of active materials on conductive
support with the help of a binder
Template based approach for electrode fabrication
Prepration of active materials in side the pores of template and template removal
Advantages of template based method •No need of expensive and resistive binders •Efficient utilisation of active matrials •Better ion diffusion path
Template Nanoarray
Electrode fabrication Conventional method Vs template based approach
MnO2 based supercapacitor • Low cost and non-toxic properties of MnO2 make it as versatile electrode
material for cheap and ecofriendly supercapacitor instead of expensive and toxic RuO2
• But the application of symmetric and aqeous electrolyte based MnO2
supercapacitor is limited due to its very low potential window (~0.6-0.9 V). Stability problems due to negative electrode also were reported.
• The voltage can be increased by using carbon or conducting polymer as one of the electrode in the supercapacitor along with MnO2.
• Use of MnO2 nanoarrays as positive electrode and PEDOT (3,4-polyethylenedioxythiophene) nanoarrays as negative electrode in KNO3 electrolyte provide high operating voltage
Preparation of Alumina template
SEM of Alumina template
Preparation of MnO2 nanoarrays
1. Electrodeposition ,Mn acetate , 0. 8 V
Alumina
Titanium
Gold
MnO2
PEDOT
Preparation of PEDOT nanoarrays
1. Electrodeposition, EDOT + LiClO4 , 1.2 V
2. Removal of template by using NaOH
2. Removal of template by using H3PO4
SEM
&
EDAX of
MnO2
nanoarray
SEM &
EDAX of
PEDOT nanoarray
Reference electrode: Ag/AgCl Counter electrode: Pt Electrolyte: 2M KNO3
Cyclic voltammogram of MnO2 nanoarray (using
three electrode cell )
Capacitance:~230 F/g
Cyclic voltammogram of PEDOT nanoarray (using
three electrode cell )
Reference electrode: Ag/AgCl Counter electrode: Pt Electrolyte: 2M KNO3 Capacitance:~140 F/g
Cyclic voltammogram of asymetric supercapacitor
Positive electrode: MnO2 nanoarray Negative electrode: PEDOT nanoarray Electrolyte: 2M KNO3
Conclusion • Asymmetric supercapacitor by using ordered MnO2 and
PEDOT nanoarrays • Potential window of the supercapacitor is higher than
symmetric supercapacitors. The high operating voltage helps to provide high energy density
Acknowledgement • Prof. Dr. Yong Lei (Research guide and Project leader) • All group members
Thank You
