| Design of MnO2-MWCNTs Based Asymmetric
Supercapacitor with Superior Electrochemical
Performance and Its Application in Powering LEDs |
R. T. Vinny,1 K. Chaitra,1 N. Nagaraju2 and N. Kathyayini1,*
pages :102-107
DOI : 10.1080/0371750X.2016.1175968 |
| Abstract |
| An asymmetric supercapacitor device (ASD) was fabricated using manganese oxidemultiwalled
carbon nanotubes (MnO2-MWCNTs) nanocomposite as positive electrode
and functionalized multiwalled carbon nanotubes (f-MWCNTs) as negative electrode.
This ASD demonstrated a specific capacitance (Cs) of 47 F.g–1 at a scan rate of 2 mV.s–1
in a wide operating potential of 0-2 V in 1 M Na2SO4. The energy density of the device
was 14.3 Wh.kg–1 at 1 A.g–1 current density. The maximum power density obtained for
the ASD was found to be 5.9 kW.kg–1 with a corresponding energy density of
7.3 Wh kg-1. The device was subjected to 20,000 galvanostatic charge-discharge cycles
at a high current density of 25 A.g–1 to test its stability. The ASD retained 65% of the
initial capacitance with 82% coulombic efficiency even at 20,000th cycle. Further,
electrochemical impedance spectroscopic (EIS) studies indicated the charge transfer
resistance (Rct) of the device as 2.6 , with a phase angle of –72o, which confirmed its
good capacitive behaviour. The ASD could power two red coloured LED lights connected
in parallel for 6 min after it was charged to 2 V at a current density of 1 A.g–1. |
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