High performance of a flexible graphene nanoplatelets supercapacitor in a stacked configuration
The energy density and working potential of conventional supercapacitor devices are in the range of 6–10 Wh/kg, which has hindered it to be implemented in electronic applications that required devices to run in a long durations at a higher voltage. Herein, we report a method for enhancing the ene...
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| Main Author: | |
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| Format: | Thesis |
| Language: | English |
| Published: |
2018
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/76746/1/FS%202018%2063%20IR.pdf |
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| Summary: | The energy density and working potential of conventional supercapacitor devices are in
the range of 6–10 Wh/kg, which has hindered it to be implemented in electronic
applications that required devices to run in a long durations at a higher voltage. Herein,
we report a method for enhancing the energy density of a device through the parallel
stacking of five copper foils electrodes coated with graphene nanoplatelets as electroactive
material. Microporous papers immersed in 2 M of aqueous sodium sulphate
electrolyte were then used as separators in between stacked copper foils to complete the
supercapacitor device. The as-assembled supercapacitor had achieved a specific
capacitance value of 142 F/g with low contact resistance of 0.05 Ω at 1 A/g. The
supercapacitor yielded optimum specific energy and specific power density of 24.64
Wh/kg and 402 W/kg at 0.8 V, respectively. Furthermore, the utilization of copper foil
current collector and microporous paper type separator give additional merit of flexibility
to the supercapacitor when an unnoticeable difference in cyclic voltammetry curves was
observed even at 45°, 90° and 180° bending angles. The supercapacitor bent up to 180°
was able to maintain high capacitance retention up to 83% after 800 cycles of continuous
charge discharge cycles. Interestingly, the working potential has been successfully
increased up to 2.4 V when three of the stacked supercapacitors were connected in series
by forming a tandem device while bended at 180 °C. Its potential for real application was
manifested by the ability to light up a light-emitting diode for 40 s when charged for 60
s. Besides that, when comparing it with the commercial available supercapacitors
(KEMET, ILLINOIS), the as-assembled supercapacitor was found to outperform it in
terms of energy density. Overall, the electrochemical performance tests have
demonstrated the high performance of aqueous-based flexible graphene nanoplatelets
supercapacitor from stacked copper foils configuration. This was found to be mainly
contributed to the proper selection of each supercapacitor components from the electrode
active material, current collector, electrolyte and separator through systematic analysis
of spectroscopy, microscopy and electrochemical characterizations. The study that has
been discussed in this thesis could pave a way to be applicable in wearable electronic
devices that required high energy density and working potential before it can be
implemented. |
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