• Environmental Engineering Research
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• v.19 no.4
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• pp.363-367
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• 2014

One chambered sediment microbial fuel cell (SMFC) was equipped with Fe, brass (Cu/Zn), Fe/Zn, Cu, Cu/carbon cloth and graphite felt anode. Graphite felt was used as common cathode. The SMFC was membrane-less and mediator-less as well. Order of anodic performance on the basis of power density was Fe/Zn ($6.90Wm^{-2}$) > Fe ($6.03Wm^{-2}$) > Cu/carbon cloth ($2.13Wm^{-2}$) > Cu ($1.13Wm^{-2}$) > brass ($Cu/Zn=0.24Wm^{-2}$) > graphite felt ($0.10Wm^{-2}$). Fe/Zn composite anode have twisted 6.73% more power than Fe alone, Cu/carbon cloth boosted power production by 65%, and brass (Cu/Zn) produced 65% less power than Cu alone. Graphite felt have shown the lowest electricity generation because of its poor galvanic potential. The estuarine sediment served as supplier of oxidants or electron producing microbial flora, which evoked electrons via a complicated direct microbial electron transfer mechanism or making biofilm, respectively. Oxidation reduction was kept to be stationary over time except at the very initial period (mostly for sediment positioning) at anodes. Based on these findings, cost effective and efficient anodic material can be suggested for better SMFC configurations and stimulate towards practical value and application.

• Journal of Electrochemical Science and Technology
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• v.7 no.3
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• pp.228-233
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• 2016

It is hard to employ the carbon materials or the lithium metal foil for the anode of lithium sulfur batteries because of the poor passivation in ether-based electrolytes and the formation of lithium dendrites, respectively. Herein, we investigated the electrochemical characteristics of lithium sulfur batteries with lithiated silicon anode in the liquid electrolytes based on ether solvents. The silicon anodes were lithiated by direct contact with lithium foil in a 1M lithium bis(trifluoromethane sulfonyl) imide (LiTFSI) solution in 1,2-dimethoxyethane (DME) and 1,3-dioxolane (DOL) at a volume ratio of 1:1. They were readily lithiated up to ~40% of their theoretical capacity with a 30 min contact time. In particular, the carbon mesh reported in our previous work was employed in order to maximize the performance by capturing the dissolved polysulfide in sulfur cathode. The reversible specific capacity of the lithiated silicon-sulfur batteries with carbon mesh was 1,129 mAh/g during the first cycle, and was maintained at 297 mAh/g even after 50 cycles at 0.2 C, without any problems of poor passivation or lithium dendrite formation.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.19 no.2
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• pp.225-231
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• 2021

The reaction between Li₂CO₃ and Cl₂ was investigated to verify its occurrence during a carbon-anode-based oxide reduction (OR) process. The reaction temperature was identified as a key factor that determines the reaction rate and maximum conversion ratio. It was found that the reaction should be conducted at or above 500℃ to convert more than 90% of the Li₂CO₃ to LiCl. Experiments conducted at various total flow rate (Q) / initial sample weight (W_i) ratios revealed that the reaction rate was controlled by the Cl₂ mass transfer under the experimental conditions adopted in this work. A linear increase in the progress of reaction with an increase in Cl₂ partial pressure (pCl₂) was observed in the pCl₂ region of 2.03-10.1 kPa for a constant Q of 100 mL·min^-1 and W_i of 1.00 g. The results of this study indicate that the reaction between Li₂CO₃ and Cl₂ is fast at 650℃ and the reaction is feasible during the OR process.

• Journal of Electrochemical Science and Technology
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• v.12 no.2
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• pp.285-295
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• 2021

The inverse spinel Cobalt ferrite (CoFe₂O₄, CFO) is considered to be a promising alternative to commercial graphite anodes for lithium ion batteries (LIBs). However, the further development of CFO is limited by its unstable structure during battery cycling and low electrical conductivity. In an effort to address the challenge, we construct three-dimensional hierarchical flower-like CFO nanoclusters (CFO NCs)-decorated carbonized cotton carbon fiber (CFO NCs/CCF) composite. This structure is consisted of microfibers and nanoflower cluster composited of CFO nanoparticle, in which CCF can be used as a long-range conductive matrix, while flower-like CFO NCs can provide abundant active sites, large electrode/electrolyte interface, short lithium ion diffusion path, and alleviated structural stress. As anode materials in LIBs, the flower-like CFO NCs/CCF exhibits excellent electrochemical performance. After 100 cycles at a current density of 0.3 A g^-1, the CFO NCs/CCF delivers a discharge/charge capacity of 1008/990 mAh g^-1. Even at a high current density of 15 A g^-1, it still maintains a charge/discharge capacity of 362/361 mAh g^-1.

• Bulletin of the Korean Chemical Society
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• v.27 no.1
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• pp.82-86
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• 2006

Propylene Carbonate (PC) has the interesting properties of being able to dissolve and dissociate lithium salts, thus leading to highly conducting electrolytes even at low temperatures. Moreover, electrolytes that contain PC are stable against oxidation at voltages up to ~5 V. However, it is known that, when lithium is intercalated into graphite in pure PC based electrolytes, solvent co-intercalation occurs, leading to the destruction of the graphite structure. (i.e., exfoliation). The objective of this study was to suppress PC decomposition and prevent exfoliation of the graphite anode by co-intercalation. Electrochemical characteristics were studied using Kawasaki mesophase fine carbon (KMFC) in different 1 M $LiPF_6$/PC-based electrolytes. Electrochemical experiments were completed using chronopotentiometry, cyclic voltammetry, impedance spectroscopy, X-ray diffraction, and scanning electron microscopy. From the observed results, we conclude that the MA and $Li_2CO_3$ additive suppressed co-intercalation of the PC electrolyte into the graphite anode. The use of additives, for reducing the extent of solvent decomposition before exfoliation of the graphite anode, could therefore enhance the stability of a KMFC electrode.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.11
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• pp.2026-2031
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• 2010

The electrical characteristics of galvanic cell which is composed of the cathode electrode(graphite, carbon and copper) and the anode electrode(Zn and Mg) were investigated. For this research as electrolyte 2~12 wt% NaCl aqueous solution were used. At graphite cathode electrodes which use Zn and Mg with the anode electrode, the open circuit voltage was 1.3V most highly. The maximum output power increased as the electrolyte concentration increased, due to a increase in ion density. When Zn and Mg with the anode electrode, the maximum output power respectively was evaluated as 2.2mW and 5.5mW about the graphite cathode electrode in the NaCl 4wt%. The research results indicated that the output power of cell which is composed with graphite with the cathode and Mg with the anode was most excellent and the efficiency of the cell could be enhanced by increasing the electrolyte concentration.

• Korean Chemical Engineering Research
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• v.56 no.6
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• pp.901-908
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• 2018

Graphite is used as a sample anode active material. However, since the maximum theoretical capacity is limited to $372mA\;h\;g^{-1}$, a new anode active material is required for the development of a high capacity lithium ion battery. The maximum theoretical capacity of Si is $4200mA\;h\;g^{-1}$, which is higher than that of graphite. However, it is not suitable for direct application to the anode active material because it has a volume expansion of 400%. In order to minimize the decrease of the discharge capacity due to the volume expansion, the Si was pulverized by the dry method to reduce the mechanical stress and the volume change of the reaction phase, and the change of the volume was suppressed by coating the carbon layers to the particle size controlled Si particles. And carbon fiber is grown like a thread on the particle surface to control secondary volume expansion and improve electrical conductivity. The physical and chemical properties of the materials were measured by XRD, SEM and TEM, and their electrochemical properties were evaluated. In this study, we have investigated the synthesis method that can be used as anode active material by improving cycle characteristics of Si.

• Korean Journal of Materials Research
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• v.18 no.9
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• pp.457-462
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• 2008

Through the electrostatic interaction between the poly-diallydimethylammonium chloride (PDDA) modified Multi-walled carbon nanotube (MWNT) and $SnO_2$ suspension in 1mM $NaNo_3$ solution, MWNT-$SnO_2$ nanocomposites (MSC) for anode electrodes of a Li-ion battery were successfully fabricated by colloidal heterocoagulation method. TEM observation showed that most of the $SnO_2$ nanoparticles were uniformly deposited on the outside surface of the MWNT. Galvanostatic charge/discharge cycling tests showed that MSC anodes exhibited higher specific capacities than bare MWNT and better cyclability than unsupported nano-$SnO_2$ anodes. Also, after 20 cycles, the MSC anode fabricated by heterocoagulation method showed more stable cycle properties than the simply mixed MSC anode. These improved electrochemical properties are attributed to the MWNT, which adsorbs the mechanical stress induced from volume change and increasing electrical conductivity of the MSC anode, and suppresses the aggregation between the $SnO_2$ nanoparticles.

• Journal of Electrochemical Science and Technology
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• v.10 no.3
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• pp.335-343
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• 2019

In this study, $Sr_2Ni_{1.8}Mo_{0.2}O_{6-{\delta}}$ (SNM) with a double perovskite structure was investigated as an alternative anode for use in the $CH_4$ fuel in solid oxide fuel cells. SNM demonstrates a double perovskite phase over $600^{\circ}C$ and marginal crystallization at higher temperatures. The Ni nanoparticles were exsolved from the SNM anode during the fabrication process. As the SNM anode demonstrates poor electrochemical and electro-catalytic properties in the $H_2$ and $CH_4$ fuels, it was modified by applying a samarium-doped ceria (SDC) coating on its surface to improve the cell performance. As a result of this SDC modification, the cell performance improved from $39.4mW/cm^2$ to $117.7mW/cm^2$ in $H_2$ and from $15.9mW/cm^2$ to $66.6mW/cm^2$ in $CH_4$ at $850^{\circ}C$. The mixed ionic and electronic conductive property of the SDC provided electrochemical oxidation sites that are beyond the triple boundary phase sites in the SNM anode. In addition, the carbon deposition on the SDC thin layer was minimized due to the SDC's excellent oxygen ion conductivity.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.1
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• pp.147-150
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• 2007

Electro-deposition of carbon film on silicon substrate in methanol solution was carried out with various current density, solution temperature and electrode spacing between anode and cathode. The carbon films with smooth surface morphology and high electrical resistance were formed when the distance between electrode was relatively wider. The electrical resistance of the carbon films were independent of both current density and solution temperature.