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Preparation of activated carbon via acidic dehydration of durian husk for supercapacitor applications
(2020-08-01)
Ukkakimapan, Pundita
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Sattayarut, Vichuda
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Wanchaem, Thanthamrong
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Yordsri, Visittapong
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Phonyiem, Mayuree
In this study, the preparation of activated carbons (ACs) via acidic dehydration of durian husk (DH) for supercapacitor application was investigated. The DH was dehydrated using sulfuric acid and subsequently activated by using sodium hydroxide as chemical reagent at 720 °C to obtain activated carbon (hereinafter referred to as DA). Surpassing the commercial ACs and the ACs derived from the conventional carbonization and activation (hereinafter referred to as CA), the DA exhibited superior properties in high surface area (2578 m2/g) and total pore volume (1.27 cm3/g). Moreover, besides carbon and oxygen, the DA contained sulfur and nitrogen in the carbon network. The DA can act as a suitable material for supercapacitor electrode with the specific gravimetric and volumetric capacitances of 145 F/g and 70 F/cm3 in an organic electrolyte. The device also showed a promising performance with an energy density of 32 Wh/kg and a power density of 316 W/kg. These results demonstrate that the preparation of ACs via acidic dehydration of DH offers the advantages in terms of simplicity, low cost, and short-time processing to achieve heteroatom self-doped ACs with a high surface area for high-performance supercapacitors.
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Investigation on electrochemical properties of sugarcane leaves-derived activated carbon by steam activation
(2020-01-01)
Ukkakimapan, Pundita
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Ukakimaparn, Prapart
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Wanchaem, Thanthamrong
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Yordsri, Visittapong
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Sattayarut, Vichuda
Sugarcane leaves (SLs) are a bio-waste from sugar production industry. To explore the value-added SLs, the SLs were used raw materials of activated carbons (ACs) by steam activation and their electrochemial properties were investigated for supercapacitor applications. The synthesis of ACs from the SLs consisted of two steps; carbonization at 500ºC and steam activation. The synthesis condition was optimized by varying activation temperature (800 and 850ºC) The porous structures were thoroughly formed on the surface after steam activation and the surface areas were reached to 630 and 639 m2 g-1 at the activation temperature of 800 and 850ºC, respectively. The SLs-derived ACs activated at 800ºC assembled in coin cell using organic electrolyte showed the highest specific capacitance of approximately 16 F g-1 with a capacitance retention of 62% when the current density increased to 1.5 A g-1. Even though there is a room to improve the electrochemical properties such as optimization of porosity and removal of inorganic component, the SLs show a potential use as raw materials of ACs for supercapacitor applications.
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Preparation and electrochemical performance of nitrogen-enriched activated carbon derived from silkworm pupae waste
(2019-01-01)
Sattayarut, Vichuda
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Chanthad, Chalathorn
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Khemthong, Pongtanawat
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Kuboon, Sanchai
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Wanchaem, Thanthamrong
In this study, nitrogen-enriched activated carbon from silkworm pupae waste (P-AC) was successfully prepared and its electrochemical performances in aqueous and organic electrolytes were investigated. Silkworm pupae waste is beneficial because it is a nitrogen-enriched, inexpensive, and locally available material. The preparation process includes hydrothermal treatment of the silkworm pupae waste at 200 °C, and chemical activation using zinc chloride at activation temperatures of 700, 800 and 900 °C (P700, P800, and P900, respectively). The nitrogen content in the P-ACs was approximately 3.8-6.4 at%, decreasing with activation temperature, while the surface area was approximately 1062-1267 m2 g-1, increasing with activation temperature. Compared to a commercial AC, the P-ACs show higher nitrogen content but lower surface area. Furthermore, the P800 exhibited superior specific capacitance (154.6 and 91.6 F g-1 in aqueous and organic electrolytes) compared to a commercial AC despite possessing smaller surface area. The high nitrogen content enhanced the pseudocapacitance and improved the electrical conductivity of the P-ACs. These properties were confirmed by relatively low series and charge transfer resistances, a capacity retention higher than 88% at a current density of 0.5 A g-1 and excellent cycling stability demonstrated by maintaining 97.6% of its capacitance after 3000 cycles. These results demonstrate that silkworm pupae waste is a viable source of nitrogen-enriched AC for application in supercapacitors.
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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
;
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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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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