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Effect of Carbonization Temperature on Physical Properties and Specific Capacitance of Activated Carbon Derived from Banana Stem and Its Application as Supercapacitor Electrodes
(2023-01-01)
Dulyaseree, Paweena
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Sama, Hasanee
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Sada, Suraida
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Ukkakimapan, Pundita
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Yordsri, Visittapong
In this work, activated carbons (ACs) for electrodes supercapacitor applications were successfully synthesized from banana stem. Banana is one of the popular fruits that is easy to grow and most parts of the plant can be used. However, banana cultivation generates a lot of wastes, especially from the stem. Thus, using banana stem as raw material for ACs was investigated. The synthesis of AC consisted of 2 processes; carbonization and activation. The advantage of a two-step synthesis was the low weight loss of charcoal. Firstly, the carbonization process was conducted by varying the temperature between 300-600°C, and then inorganic elements were removed by treatment with 1 M sulfuric acid. After that, activation was conducted at 720°C under an argon atmosphere. The electrochemical properties of banana stem-derived ACs (BCH-ACs) were studied using sodium sulfate as an electrolyte. The BCH-ACs carbonized at 400°C showed the highest performance with a specific capacitance of 55.45 Fg-1, an energy density of 7.70 Whkg-1 and a power density of 133.94 Wkg-1. The highest specific capacitance of the BCH400-AC was likely due to the increase in the amount of oxygenated functional group, which facilitated the access of electrolyte ions into the electrode. These results suggest that banana stem can be used to synthesize ACs via carbonization at 400°C, and the ACs generated can be applied as electrode in supercapacitors.
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Nitrogen-doped graphene nanosheet-double-walled carbon nanotube hybrid nanostructures for high-performance supercapacitors
(2021-09-01)
Muangrat, Worawut
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Obata, Michiko
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Htay, Myo Than
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Fujishige, Masatsugu
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Dulyaseree, Paweena
A hybrid nitrogen-doped graphene nanosheet-grafted double-walled carbon nanotube (NG-DWCNT) was synthesized by chemical vapor deposition (CVD). Double-walled carbon nanotube (DWCNT) was synthesized by floating catalytic CVD using ferrocene and thiophene dissolved in ethanol. NG was directly grafted onto the DWCNT bundles by thermal CVD using mixed ethanol-urea solution. The NG possess sharp-edged petal-like structure on one-dimensional DWCNT bundle. The NG-DWCNT showed the nitrogen content of approximately 1.93 at%. The NG-DWCNT hybrid nanostructures exhibited a higher specific capacitance of 563 F g−1 than that of the DWCNT and un-doped G-DWCNT. The improvement of capacitance value is attributed to the synergic effect of the nitrogen doping together with the sharp-edged petal-like structure of the NG. The facile technique by CVD method provides a promising approach for simple and low-cost technique to synthesize the NG-DWCNT hybrid nanostructures. A hybrid carbon nanostructure of NG-DWCNT has a potential application in electrochemical conversion and energy storage devices.
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Effect of acid treatment substrate for supercapacitor electrode based on multi-walled carbon nanotubes
(2021-04-12)
Dulyaseree, Paweena
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Wongwiriyapan, Winadda
Effect of acid treatment substrate for supercapacitor based on multi-walled carbon nanotubes (MWNTs) electrode was investigated. The electrode was used as stainless steel type 304 (SS304) and was with hydrochloric acid (HCl) acid-treated before use. Firstly, SS304 substrates were soaked in 37% HCl for designated time. Acid treatment times were varied at 0, 5, 10 and 15 min. Their surface morphology, elemental components and hydrophilicity property of the acid-treated SS304 were analyzed. The 10-min-treated SS304 show the lowest contact angles, indicating the best hydrophilicity property. Electrode material was prepared by composites of MWNTs, polyvinylidene fluoride (PVDF) and n-methyl-2-pyrrolidone (NMP) with an area of 5x5 mm2. Their cyclic voltammetry (CV), galvanostatic charge/discharge (CD) and electrochemical impedance spectroscopy (EIS) were characterized. The 10-min-treated SS304 exhibits the best performance with a specific capacitance (SC) of 261.04 Fg-1. The improvement of the SC of the acid-treated substrate was contributed to the adhesion improvement between a current collector and an electrode material, and the hydrophilicity improvement, resulting in a large amount of electrolyte ions accessing into the electrode materials and subsequently enhancement of their capacitive characteristics.
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Nitrogen self-doped activated carbons: Via the direct activation of Samanea saman leaves for high energy density supercapacitors
(2019-01-01)
Sattayarut, Vichuda
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Wanchaem, Thanthamrong
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Ukkakimapan, Pundita
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Yordsri, Visittapong
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Dulyaseree, Paweena
In this study, nitrogen self-doped activated carbons (ACs) obtained via the direct activation of Samanea saman green leaves (SSLs) for high energy density supercapacitors were investigated. The SSL-derived direct-activated carbons (hereinafter referred to SD-ACs) were synthesized by impregnating sodium hydroxide as an activating agent and heating up to 720 °C without a hydrothermal carbonization or pyrolysis step. The optimum condition was investigated by varying the weight ratio of raw SSLs to NaOH. Surpassing the ACs derived from the two-step convention method, SD-ACs showed superior properties, including a higher surface area (2930 m2 g-1), total pore volume (1.37 cm3 g-1) and nitrogen content (4.6 at%). Moreover, SD-ACs exhibited enhanced electrochemical properties with specific gravimetric and volumetric capacitances of 179 F g-1 and 88 F cm-3 in an organic electrolyte, respectively, a high capacitance retention of approximately 87% at a current density of 0.5 A g-1 and excellent cycling stability of 97.5% after 3000 cycles at a current density of 5 A g-1. Moreover, the potential window of the supercapacitor cell was extended to 3.5 V with a significantly enhanced energy density of up to 79 W h kg-1. These results demonstrate that the direct activation of nitrogen-enriched SSLs offers advantages in terms of simplicity, low-cost and sustainable synthetic route to achieve nitrogen self-doped ACs for high energy density supercapacitors, which exhibit superior properties to that of ACs prepared via the conventional method.
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Preparation of activated carbon from bamboo-cellulose fiber and its use for EDLC electrode material
(2017-04-01)
Fujishige, Masatsugu
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Yoshida, Ichiro
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Toya, Yumiko
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Banba, Yasuo
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Oshida, Kyo ichi
Carbonization and post activation of bamboo-cellulose fiber was carried out. The carbonization was performed at 600°C, 800°C and 1000°C in argon atmosphere. Then, they were activated by heating solid mixture of carbonized bamboo and sodium hydroxide (NaOH) at 720°C in argon atmosphere. The largest specific surface area of the resulting activated carbon (carbonized at 600°C) was 2366m2/g with the micropore volume of 0.71cm3/g and mesopore volume of 0.06cm3/g. It was found that the carbonization temperature is very important to obtain nanoporous carbon with large specific surface area. The distributions of interlayer spacing were estimated from the power spectra of the TEM images of the carbonized samples. It showed the interlayer spacing of basic structural unit (BSU) decreased from 0.49nm (BC-0600) through 0.47nm (BC-0800) to 0.45nm (BC-1000). The activated carbon was used as the host material of the electrodes of coin type electric double-layer capacitor (EDLC) with organic electrolyte. The observed specific capacitance was 43F/g (23F/cm3) for the activated carbon (carbonized at 600°C), comparable to 44F/g (22F/cm3) of commercial activated carbon (MSP). The corresponding values for the activated carbons (carbonized at 800°C and 1000°C) were 40F/g (23F/cm3) and 17F/g (12F/cm3), respectively.
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Facile synthesis of hybrid manganese oxide and multiwalled carbon nanotube by two-step electrodeposition for supercapacitor electrode
(2017-01-01)
Wanchaem, Thanthamrong
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Rattanamai, Songsak
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Dulyaseree, Paweena
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Khanchaitit, Paisan
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Wongwiriyapan, Winadda
This work presents a facile synthesis of hybrid manganese oxide and multiwalled carbon nanotube (MnO<inf>x</inf>/MWCNT) by two-step electrodeposition technique for supercapacitor electrode application. Firstly, MWCNT was deposited onto SS304 substrate by electrophoretic deposition at a constant voltage of 7 V for 5 min. MWCNT solution was prepared using sodium dodecylbenzenesulfonate (SBDS) as a surfactant. Next, MnO<inf>x</inf> was deposited onto the pre-deposited MWCNT/SS304 substrate by galvanostatic electrodeposition using 0.1 M manganese sulfate (MnSO<inf>4</inf>) solution as a precursor. The electrodeposition condition was set at a constant current of 1 mA/cm2 for 5-15 min. Nanosheet array of MnO<inf>x</inf> was formed uniformly on MWCNT. At the deposition time of 10 min, the thickness of MnO<inf>x</inf> nanosheet was approximately 40 nm. Hybrid MnO<inf>x</inf>/MWCNT was characterized its electrochemical properties by cyclic voltammetry, galvanostatic charge-discharge, and electrochemical Impedance spectroscopy. Hybrid MnO<inf>x</inf>/MWCNT shows an improved specific capacitance of 267.03 F·g-1 with a series resistance of 5.17 Ω, surpassing electrode material with only MnO<inf>x</inf> or MWCNT. The high specific capacitance would be ascribed to the integration of MWCNT and MnO<inf>x</inf> functions. MWCNT may act as a platform for MnO<inf>x</inf> deposition, resulting in an increase in electrochemically active surface area of MnO<inf>x</inf>. The obtained results indicate that this two-step electrodeposition method allows tailor-made hybrid materials with nanoscale control without using harsh and toxic chemicals or high synthesis temperature.
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Optimized manganese oxide nanosheet/manganese oxide thin film/ multiwalled carbon nanotubes as hybrid electrode materials for supercapacitors
(2017-01-01)
Rattanamai, Songsak
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Dulyaseree, Paweena
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Wanchaem, Thanthumrong
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Wongwiriyapan, Winadda
Manganese oxide nanosheet/manganese oxide thin film/multiwalled carbon nanotubes(s-MnO<inf>x</inf>/f-MnO<inf>x</inf>/MWNTs) were used as hybrid electrode materials for supercapacitor application. Supercapacitor performance based on these hybrid materials was optimized by varying morphologies of s-MnO<inf>x</inf>. Firstly, a MWNT paste was coated onto nickel (Ni) foam and subsequently f-MnO<inf>x</inf> was deposited onto the pre-coated MWNTs/Ni foam by galvanostatic (GS) mode of electrodeposition technique at a constant current of 1 mA/cm2 using 0.1 M KMnO<inf>4</inf> as a precursor with a fix deposited time of 5 min. Finally, s-MnO<inf>x</inf> was deposited onto the prepared f-MnO<inf>x</inf>/MWNTs/Ni foam by GS mode of electrodeposition technique at a constant current of 1 mA/cm2 using 0.1 M KMnO<inf>4</inf> as precursor with different deposited times of 10, 15 and 20 min. Each hybrid s-MnO<inf>x</inf>/f-MnO<inf>x</inf>/MWNTs electrode was characterized by cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopy. The s-MnO<inf>x</inf>/f-MnO<inf>x</inf>/MWNTs electrode prepared by 15-min-deposited s-MnO<inf>x</inf> shows the highest specific capacitance. The capacitance improvement is attributed to the increase of electrode surface area.
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Nitrogen-rich green leaves of papaya and: Coccinia grandis as precursors of activated carbon and their electrochemical properties
(2017-01-01)
Dulyaseree, Paweena
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Fujishige, Masatsugu
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Yoshida, Ichiro
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Toya, Yumiko
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Banba, Yasuo
Activated carbon (AC) was synthesized from papaya and Coccinia grandis leaves (PL-AC and CL-AC, respectively) which are nitrogen-rich precursors and their electrochemical properties were investigated. The synthesis process included carbonization at 400 °C, impurity removal by H<inf>2</inf>SO<inf>4</inf> cleaning, and post activation by NaOH at 720 °C. Surpassing the conventional bamboo-derived AC (B-AC), PL- and CL-ACs show relatively high surface areas of 2664 and 2576 m2 g-1, respectively. Moreover, the nitrogen contents in the PL- and CL-ACs were approximately 2.3 and 1.8 at%, respectively. Furthermore, the electrochemical properties of the synthesized PL- and CL-ACs were investigated using both aqueous and organic electrolytes. The specific capacitances of the PL- and CL-ACs were 98.47 and 89.91 F g-1, respectively, in Na<inf>2</inf>SO<inf>4</inf> electrolyte. Especially, compared to the B-AC, the PL-AC shows a dramatic decrease in series resistances (R<inf>S</inf>) from 1.33 to 0.53 Ω and charge transfer resistances (R<inf>CT</inf>) from 25.83 to 9.00 Ω. The decrease of R<inf>S</inf> and R<inf>CT</inf> is attributed to the existence of nitrogen in the PL-AC, resulting in a higher conductivity of electrode material and an enhancement of the charge transfer between electrode material and electrolyte. The large surface area of the PL- and CL-ACs was successfully achieved without detriment to the electrical conductivity. These results suggest that nitrogen-rich PL and CL are potential precursors for the synthesis of nitrogen-doped AC in a one-step process, which can be used as an alternative electrode material for electrochemical capacitors and can potentially be applied for large-scale industrial production with low cost.
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Effects of microwave and oxygen plasma treatments on capacitive characteristics of supercapacitor based on multiwalled carbon nanotubes
(2016-02-01)
Dulyaseree, Paweena
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Yordsri, Visittapong
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Wongwiriyapan, Winadda
The effects of microwave and oxygen plasma treatments on the capacitive characteristics of a supercapacitor based on multiwalled carbon nanotubes (MWNTs) were investigated. MWNTs were heat-treated under air ambient at 500 °C for 1 h, and subsequently microwave-treated at 650W for 70 s (m-MWNTs). Another batch of MWNTs was treated by oxygen plasma for 30 min (p-MWNTs). Pristine MWNTs, m-MWNTs, and p-MWNTs were separately used as electrode materials for supercapacitors. Their cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy results were analyzed. The p-MWNTs show the best performance with a specific capacitance of 238.23 F.g-1. The capacitance improvement is attributed to the increase in the number of oxygen-containing functional groups, as evidenced by Fourier transform-infrared spectroscopy and contact angle measurement. These results suggest that oxygen plasma treatment is a rapid and efficient method for oxygen functionalization.
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Supercapacitor based on multi-walled carbon nanotubes/carbon black composites-coated wooden sheet
(2014-01-01)
Dulyaseree, Paweena
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Jarernboon, Wirat
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Wongwiriyapan, Winadda
Supercapacitor consists of two carbon electrodes and wooden sheet as a separator. Three types of carbon electrodes were prepared; carbon black (CB), multi-walled carbon nanotubes (MWNTs) and composites of MWNTs and CB (MWNTs-CB). Electrode pastes were coated on both sides of wooden sheet. The thickness of wooden sheet was varies from 1 mm to 5 mm. The morphology of CB, MWNTs and MWNTs-CB were characterized by scanning electron microscopy (SEM). The supercapacitor performance was characterized by cyclic voltammetry and galvanostatic charge/discharge techniques. Among carbon electrode materials, MWNTs-CB shows the highest specific capacitance. The high specific capacitance of MWNTs-CB may be due to the high surface area of MWNTs incorporated with CB acting as spacer for MWNTs agglomeration protection and electrolyteelectrode accessibility improvement. Moreover, wooden sheet with a thickness of 2 mm shows the highest specific capacitance.

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