Browsing by Author "Chang, Man-Lin"

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Electrochemical Properties of CNT/MnO2 Hybrid Nanostructure with Low-Temperature Hydrothermal Synthesis as High-Performance Supercapacitor
(2019-06-25)
Li, Wei-Shuo
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Chang, Man-Lin
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Chuang, Kai-Chi
;
Li, Yi-Shao
;
Luo, Jun-Dao
Multi-walled carbon nanotubes (CNTs)/manganese dioxide (MnO2) nanocomposites were fabricated using the low-temperature hydrothermal method with no oxidant addition as hybrid supercapacitors. The electrochemical behaviors of CNTs-MnO2 were systematically investigated by cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy. The specific capacitance was promoted from 30.3 F g(-1) to 405.15 F g(-1) with a hydrothermal reaction time of 5 min. Compared to pristine CNTs, the improvement ratio of the specific capacitance of a hydrothermal reaction time of 5 min was 13.4 times under the condition of a 1 M Na2SO4 electrolyte at a scan rate of 100 mVs(-1). The CNTs-MnO2 electrode also demonstrated better cycling stability after 1000 cycles. Moreover, this study demonstrates that CNTs-MnO2 electrodes have a low-temperature facile synthesis, high specific capacitance, and good cycle stability. Thus, these good supercapacitors electrodes are promising for the development in energy-storage devices in the future. (c) 2019 The Electrochemical Society.
Enhancement on the characteristics of supercapacitors using surface modification of sprayed-carbon nanotube thin film electrodes with oxygen plasma treatment
(2019-05-01)
Li, Wei-Shuo
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Chuang, Kai-Chi
;
Li, Yi-Shao
;
Luo, Jun-Dao
;
Chang, Man-Lin
The surface characteristics of the carbon nanotube thin films (CNTFs) electrodes have been treated with the oxygen plasma to successfully demonstrate, the greater specific capacitance of the supercapacitors. With the treatment time of 60 s, the specific capacitance could raise from 23.7 to 49.3 F g(-1) with respect to the as-sprayed CNTFs under the cyclic voltammetry measurement. The improvement ratio in specific capacitance of plasma-treated supercapacitor as compare to none-treated supercapacitor was 2.1 times under condition of 1 M Na2SO4 solution at a scan rate of 100 mV s(-1). The capacitance retention remain about 96.5% after 5000 cycles at current density of 1 A g(-1). Hence, this study exhibited that the modified CNTFs as the electrodes of supercapacitors are promising in the future developments for the energy-storage devices. (C) 2019 The Japan Society of Applied Physics
Facile synthesis of CNTs/Co(OH)(2) hybrid nanostructures for high-performance electrochemical supercapacitor
(2020-01-01)
Li, Wei-Shuo
;
Chang, Man-Lin
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Cheng, Huang-Chung
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
The sprayed carbon nanotubes (CNTs) and cobalt hydroxide (Co(OH)(2)) were successfully prepared by a simple low-temperature hydrothermal method as supercapacitor electrode. With the hydrothermal time of 120 min, highest specific capacitance of 1154.01 F/g at a scan rate of 20 m Vs(-1) in 3 M KOH was observed. The CNTs/Co (OH)(2) hybrid structures demonstrates an enhanced specific capacitance and the best cycling stability with capacitance retention of 82% after 1000 cycles. Thus, this study exhibited that the CNTs/Co(OH)(2) has great potential application as electrode materials for electrochemical supercapacitors.