Comparison of nano-MnO2 derived from different manganese sources and influence of active material weight ratio on performance of nano-MnO2/activated carbon supercapacitor

2010 ◽  
Vol 51 (12) ◽  
pp. 2588-2594 ◽  
Author(s):  
Anbao Yuan ◽  
Xiuling Wang ◽  
Yuqin Wang ◽  
Jie Hu
2020 ◽  
Vol 5 (3) ◽  
pp. 221
Author(s):  
Muhammad Azam ◽  
Muhammad Anas ◽  
Erniwati Erniwati

This study aims to determine the effect of variation of activation temperature of activated carbon from sugar palm bunches of chemically activatied with the activation agent of potassium silicate (K2SiO3) on the adsorption capacity of iodine and methylene blue. Activated carbon from bunches of sugar palmacquired in four steps: preparationsteps, carbonizationstepsusing the pyrolysis reactor with temperature of 300 oC - 400 oC for 8 hours and chemical activation using of potassium silicate (K2SiO3) activator in weight ratio of 2: 1 and physical activation using the electric furnace for 30 minutes with temperature variation of600 oC, 650 oC, 700 oC, 750 oC and 800 oC. The iodine and methyleneblue adsorption testedby Titrimetric method and Spectrophotometry methodrespectively. The results of the adsorption of iodine and methylene blue activated carbon from sugar palm bunches increased from 240.55 mg/g and 63.14 mg/g at a temperature of 600 oC to achieve the highest adsorption capacity of 325.80 mg/g and 73.59 mg/g at temperature of 700 oC and decreased by 257.54 mg/g and 52.03 mg/g at a temperature of 800 oCrespectively.However, it does not meet to Indonesia standard (Standard Nasional Indonesia/SNI), which is 750 mg/g and 120 mg/g respectively.


2020 ◽  
Vol 1000 ◽  
pp. 50-57
Author(s):  
Jagad Paduraksa ◽  
Muhammad Luthfi ◽  
Ariono Verdianto ◽  
Achmad Subhan ◽  
Wahyu Bambang Widayatno ◽  
...  

Lithium-Ion Capacitor (LIC) has shown promising performance to meet the needs of high energy and power-density-energy storage system in the era of electric vehicles nowadays. The development of electrode materials and electrolytes in recent years has improvised LIC performance significantly. One of the active materials of LIC electrodes, activated carbon (AC), can be synthesized from various biomass, one of which is the water hyacinth. Its abundant availability and low utilization make the water hyacinth as a promising activated carbon source. To observe the most optimal physical properties of AC, this study also compares various activation temperatures. In this study, full cell LIC was fabricated using LTO based anode, and water hyacinth derived AC as the cathode. The LIC full cell was further characterized to see the material properties and electrochemical performance. Water hyacinth derived LIC can achieve a specific capacitance of 32.11 F/g, the specific energy of 17.83 Wh/kg, and a specific power of 160.53 W/kg.


2010 ◽  
Vol 132 (2) ◽  
Author(s):  
Yi-Chun Chen ◽  
Chao-Ying Yu ◽  
Chih-Ping Chen ◽  
Shu-Hua Chan ◽  
Ching Ting

A novel soluble conjugated polymers, P2, with coplanar thiophene-phenylene-thiophene unit is designed and synthesized as suitable active material used in tandem cells to compensate the poly(3-hexylthiophene) (P3HT)/[6,6]-phenyl-C71 butyric acid methyl ester (PC71BM) bulk-heterojunction cell in this paper. P2 polymer bears advantages in both low optical bandgap (1.7 eV) and high hole mobility properties (3.4×10−3 cm2/V-s from field-effect transistor measurement). Furthermore, the electrochemical studies of P2 indicate desirable highest occupied molecular orbital/lowest unoccupied molecular orbital (HOMO/LUMO) band structure that enables a high open circuit voltage when pairing with PCBM acceptor. The best power conversion efficiency of this polymer solar cell thus far based on P2/PC71BM system with a weight ratio of 1:3 reached 4.4% with a short circuit current density (Jsc) of 10.2 mA/cm2, an open circuit voltage (Voc) of 0.81 V, and a fill factor (FF) of 0.53 under air mass (AM) 1.5 G (100 mW/cm2). The preliminary data of the tandem cell with indium tin oxide (ITO) glass/PEDOT:PSS/P2:PC71BM/TiOx/PEDOT:PSS/P3HT:PC71BM/TiOx/Al configuration has reached Jsc of 6.2 mA/cm2, Voc of 1.33 V, FF of 0.56 and an overall efficiency of 4.6% under AM 1.5 G (100 mW/cm2).


2013 ◽  
Vol 1540 ◽  
Author(s):  
Lanlan Zhong ◽  
Andi Xie ◽  
Lorenzo Mangolini

ABSTRACTSilicon is a very promising material for anodes of lithium ion batteries. It exhibits a high theoretical capacity of 3579 mAh/g. However, during the lithiation and de-lithiation, silicon materials experience up to a 300% volume change, leading to poor cyclability [1-2]. Research shows that reducing the silicon particle size can mitigate this problem. Carbon nanotubes (CNTs) function well as electrode materials in electrolytic cells because of their high electrical conductivity and surface area. In this work, we combine silicon nanoparticles (Si NPs) and CNTs as anode materials. Si NPs are generated using a plasma-enhanced chemical vapor deposition technique and their surface is modified with a 12-carbon long aliphatic chain to impart solubility in non-polar solvents. They are applied onto a nanotube-based layer using a wet-phase deposition technique. SEM and TEM analysis confirm that they form a conformal coating onto the nanotube surface. The CNTs - Si NPs composite active material is tested in half-cells where lithium foil acts as counter electrode. We have achieved an average of 810 mAh/g discharge capacity for composites with a CNTs to Si NPs weight ratio of 1:1. We expect to be able to increase the discharge capacity by increasing the Si NPs weight content.


2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Li Bai ◽  
Xianyou Wang ◽  
Xingyan Wang ◽  
Xiaoyan Zhang ◽  
Wanmei Long ◽  
...  

Dandelion-likeγ-manganese dioxide (γ-MnO2) nanofibre/activated carbon microbeads (ACMBs) composite is prepared by an in situ coating technique. The structure and morphology of the composite are characterized by scanning electron microscopy and X-ray diffraction. The results show thatγ-MnO2nanofibre is uniformly encapsulated on the surface of ACMB, and the composite finally becomes a dandelion-like microbead. Cyclic voltammetry, galvanostatic current charge/discharge, and cycle life measurements are used to evaluate the electrochemical behaviors of the composite. Since the composite is able to undergo pseudofaradic charge transfer reactions and hereto contributes together with the double-layer effect to the total capacitance of the material, the specific capacitance of the composite is as high as 375.9 F g-1at a scan rate of 1 mV s-1, which is significantly higher than the pure ACMB. Besides, the capacitance retention of the supercapacitor using the composite as electrode-active material keeps still 93% after 1000 cycles.


Jurnal MIPA ◽  
2014 ◽  
Vol 3 (2) ◽  
pp. 87
Author(s):  
Christmas Togas ◽  
Audy D. Wuntu ◽  
Harry S. J. Koleangan

Telah dilakukan penelitian untuk mempelajari pengaruh penambahan karbon aktif (KA) pada fotokatalis TiO2 serta aktivitas fotokatalitiknya dalam proses fotodegradasi zat warna metanil yellow. Penelitian diawali dengan pembuatan KA dari tempurung kelapa, kemudian dilakukan modifikasi fotokatalis TiO2–KA. Eksperiman fotodegradasi metanil yellow oleh fotokatalis TiO2–KA dilakukan dengan perbandingan berat TiO2:KA sebesar 9,9:0,1 dan 9,5:0,5 dan konsentrasi metanil yellow 2–50 ppm, serta variasi waktu penyinaran sinar UV selama 1, 2, 3, 4, 5, 19 dan 20 jam. Hasil penelitian menunjukkan bahwa persentase proses fotodegradasi tertinggi diperoleh pada perbandingan berat TiO2:KA (9,9:0,1) dan aktivitas fotodegradasi semakin meningkat seiring dengan bertambahnya waktu penyinaran.A research had been conducted to study the effect of the addition of activated carbon (AC) on TiO2 photocatalyst and its photocatalytic activity in photodegradation process of metanil yellow dye. The research was performed through the preparation of activated carbon from coconut shell and modification of photocatalyst TiO2–AC. Experiment of metanil yellow photodegradation by photocatalyst TiO2–AC was performed at the weight ratio of TiO2:AC of 9,9:0,1 and 9,5:0,5 with the concentrations of metanil yellow of 2–50 ppm, and time variations of UV rays irradiation of 1, 2, 3, 4, 5, 19 and 20 hours. The results showed that the highest percentage of photodegradation process obtained at the weight ratio of TiO2:AC of 9,9:0,1 and the photodegradation activity was increased along with increasing irradiation time


Molekul ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. 235
Author(s):  
Annisa Syifaurrahma ◽  
Arnelli Arnelli ◽  
Yayuk Astuti

A lithium ion battery anode active material comprised of LiOH (Li) and coconut shell activated carbon (AC) has been synthesized with Li/AC ratios of (w/w) 1/1, 2/1, 3/1, and 4/1 through the sol gel method. The present study aims to ascertain the best Li/AC ratio that produces an anode active material with the best electrical conductivity value and determine the characteristics of the anode active material in terms of functional groups, surface area, crystallinity, and capacity. Based on the electrical conductivity test using LCR, the active material Li/AC 2/1 had the highest electrical conductivity with a value of 2.064x10-3 Sm-1. The conductivity achieved was slightly smaller than that of the active material with no addition of LiOH on the activated carbon at an electrical conductivity of 5.434x10-3 Sm-1. The FTIR spectra of the activated carbon and Li/AC 2/1 showed differences with in the Li-O-C group absorption at 1075 cm-1 wavenumber and the wide absorption in the area of 547.5 cm-1 that represents Li-O vibration. Based on the results of SAA, the activated carbon had a larger surface area than Li/AC 2/1 at 17.057 m2g-1 and 5.615 m2g-1, respectively. The crystallinity of both active materials was low shown by the widening of the diffraction peaks. Tests with cyclic voltammetry (CV) proved that there was a reduction-oxidation reaction for the two samples in the first cycle with a large charge and discharge capacities of the activated carbon of 150.989 mAh and 92.040 mAh, while for Li/AC 2/1 they were 91.103 mAh and 47.580 mAh.


2021 ◽  
Vol 2 (3) ◽  
pp. 258-268
Author(s):  
Henry Oghenero Orugba ◽  
Kigho Moses Oghenejoboh ◽  
Ufuoma Modupe Oghenejoboh ◽  
Onogwarite E. Ohimor

This work investigated the viability of a non-edible oil obtained from raphia africana in the production of biodiesel using a novel heterogeneous catalyst derived from turtle shells (Centrochelys sulcata). The study also proposed the use of acetone as co-solvent to enhance the solubility of the reacting mixtures. The turtle shells were calcined at 900oC for 3hr, impregnated in KOH to improve its activity and then supported with activated carbon produced from cassava peels to increase its surface area. The influences of KOH concentration, catalyst loading, catalyst/carbon mix ratio and concentration of acetone/methanol on the yield of biodiesel were investigated. The results obtained revealed that maximum biodiesel yield of 93% was obtained from the bio-oil at KOH concentration of 30% (w/w), catalyst loading of 6.5%, solvent/methanol ratio of 0.4 and catalyst/carbon weight ratio of 1.25. The activated carbon supported turtle shell catalyst has been found to possess very high catalytic activity converting bio-oil with high saturated fatty acid content to biodiesel with excellent fuel properties having low saturated fatty acids profile. Doi: 10.28991/HEF-2021-02-03-07 Full Text: PDF


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