• Title, Summary, Keyword: Electrolyte Additive

Search Result 116, Processing Time 0.027 seconds

Micro Emulsion Synthesis of LaCoO3 Nanoparticles and their Electrochemical Catalytic Activity

  • Islam, Mobinul;Jeong, Min-Gi;Ghani, Faizan;Jung, Hun-Gi
    • Journal of Electrochemical Science and Technology
    • /
    • v.6 no.4
    • /
    • pp.121-130
    • /
    • 2015
  • The micro emulsion method has been successfully used for preparing perovskite LaCoO3 with uniform, fine-shaped nanoparticles showing high activity as electro catalysts in oxygen reduction reactions (ORRs). They are, therefore, promising candidates for the air-cathode in metal-air rechargeable batteries. Since the activity of a catalyst is highly dependent on its specific surface area, nanoparticles of the perovskite catalyst are desirable for catalyzing both oxygen reduction and evolution reactions. Herein, LaCoO3 powder was also prepared by sol-gel method for comparison, with a broad particle distribution and high agglomeration. The electro catalytic properties of LaCoO3 and LaCoO3-carbon Super P mixture layers toward the ORR were studied comparatively using the rotating disk electrode technique in 0.1 M KOH electrolyte to elucidate the effect of carbon Super P. Koutecky-Levich theory was applied to acquire the overall electron transfer number (n) during the ORR, calculated to be ~3.74 for the LaCoO3-Super P mixture, quite close to the theoretical value (4.0), and ~2.7 for carbon-free LaCoO3. A synergistic effect toward the ORR is observed when carbon is present in the LaCoO3 layer. Carbon is assumed to be more than an additive, enhancing the electronic conductivity of the oxide catalyst. It is suggested that ORRs, catalyzed by the LaCoO3-Super P mixture, are dominated by a 2+2-electron transfer pathway to form the final, hydroxyl ion product.

The Influence of Gelatin Additives on the Mechanical Properties of Electrodeposited Cu Thin Films (젤라틴 첨가에 의한 구리 박막의 기계적 특성 변화)

  • Kim, Minho;Cha, Hee-Ryoung;Choi, Changsoon;Kim, Jong-Man;Lee, Dongyun
    • Korean Journal of Metals and Materials
    • /
    • v.48 no.10
    • /
    • pp.884-892
    • /
    • 2010
  • To modify the physical properties of Cu thin films, gelatin is generally used as an additive. In this study, we assessed the effect of gelatin on the mechanical properties of electrodeposited Cu films. For this purpose, Cu/gelatin composite films were fabricated by adding 100 ppm of gelatin to an electrolyte, and tension and indentation tests were then performed. Additional tests based on pure Cu films were also performed for comparison. The Cu films containing gelatin presented a smaller grain size compared to that of pure Cu films. This increased the hardness of the Cu films, but addition of gelatin did not significantly affect the elastic modulus of the films. Cu films prepared at room temperature showed no significant change in the yield strength and tensile strength with an addition of gelatin, but we observed a dramatic decrease in the elongation. In contrast, Cu films prepared at $40^{\circ}C$ with gelatin presented a significant increase in the yield strength and tensile strength after the addition of gelatin. Elongation was not affected by adding gelatin. Presumably, the results would be closely related to the preferred orientation of the Cu thin film with the addition of gelatin and at temperatures that lead to a change in the microstructure of the Cu thin films.

Effects of Additive Binder Contents on Electrode Properties of Carbon Anode for Fluorine Electrolysis (불소전해용 양극탄소전극의 전극특성에 미치는 첨가 결합제의 영향)

  • Ahn, Hong Joo;Oh, Han Jun;Chi, Choong Soo;Kim, Young Cheul;Ko, Young Shin
    • Journal of the Korean Chemical Society
    • /
    • v.45 no.5
    • /
    • pp.413-421
    • /
    • 2001
  • The carbon electrodes for fluorine electrolysis were prepared from petroleum cokes containing coal tar pitch as binder and the effects of binder contents on electrode properties were investigated. The evaluations were performed by cyclic voltammogram in the 0.5 M $K_2SO_4$ solution with 1 mM $[Fe$(CN)_6$]^{3-}$/$[Fe$(CN)_6$]^{4-}$redox couple, mechanical strength, and electrochemical behaviour in molten $KF{\cdot}2HF$ electrolyte. It was revealed that the carbon anode formed with 40wt% of coal tar pitch as binder has a better electrode properties compared to those of the other carbon anode, which led to the increase in the effective internal surface area due to proper size and distribution of pores on carbon anode.

  • PDF

The Effects of the Nano-sized Adsorbing Material on the Electrochemical Properties of Sulfur Cathode for Lithium/Sulfur Secondary Battery (나노 흡착제가 Li/S 이차전지용 유황양극의 전기화학적 특성에 미치는 영향)

  • Song, Min-Sang;Han, Sang-Choel;Kim, Hyun-Seok;Ahn, Hyo-Jun;Lee, Jai-Young
    • Transactions of the Korean hydrogen and new energy society
    • /
    • v.13 no.4
    • /
    • pp.259-269
    • /
    • 2002
  • A battery based on the lithium/elemental sulfur redox couple has the advantage of high theoretical specific capacity of 1,675 mAh/g-sulfur. However, Li/S battery has bad cyclic durability at room temperature due to sulfur active material loss resulting from lithium polysulfide dissolution. To improve the cycle life of Li/S battery, PEGDME (Poly(ethylene glycol) dimethyl ether) 500 containing 1M LiTFSI salt which has high viscosity was used as electrolyte to retard the polysulfide dissolution and nano-sized $Mg_{0.6}Ni_{0.4}O$ was added to sulfur cathode as additive to adsorb soluble polysulfide within sulfur cathode. From experimental results, the improvement of the capacity and cycle life of Li/S battery was observed( maximum discharge capacity : 1,185 mAh/g-sulfur, C50/C1 = 85 % ). Through the charge-discharge test, we knew that PEGDME 500 played a role of preventing incomplete charge-discharge $behavior^{1,2)$. And then, in sulfur dissolution analysis and rate capability test, we first confirmed that nano-sized $Mg_{0.6}Ni_{0.4}O$ had polysulfide adsorbing effect and catalytic effect of promoting the Li/S redox reaction. In addition, from BET surface area analysis, we also verified that it played the part of increasing the porosity of sulfur cathode.

Dye-sensitized Solar Cells with Mesoporous TiO2 Film Manufactured by Spin Coating Methode (스핀코팅법에 의해 제조되어진 나노다공질 TiO2 전극막을 이용한 염료감응형 태양전지)

  • 구보근;이동윤;이원재;김현주;송재성
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.17 no.9
    • /
    • pp.1001-1005
    • /
    • 2004
  • Rye-sensitized solar cell (DSSC) is a new class of solar cell, which consists of nanoporous TiO$_2$ electrode, dye-sensitizer, electrolyte, and counter electrode. Such cell is operated in sunlight via the principle of photosynthetic electrochemistry. In order to obtain the good dispersion of nano size TiO$_2$ particles In slurry, the pH of solvent, the sort and quantify of solvent additive and the quantity of surfactant were adjusted. As results, the lower the pH of solvent was the lower the viscosity of the slurry became. The addition of ethylene glycol and propylene glycol to dilute HNO$_3$ brought about the lowering of viscosity and the enhancement of stability in slurry. The addition of surfactant lowered the viscosity of slurry. It was possible to obtain the homogeneous and uniformly dispersed mesoporous TiO$_2$ film using the dilute HNO$_3$ solvent of pH 2 with the addition of ethylene glycol and neutral surfactant. DSSC was assembled with TiO$_2$ electrode and Pt electrode, and its photoelectric property was measured using the monochromatic wavelength in the rangee of 350∼700 nm.

Improved Cycling Ability of Si-SiO2-graphite Composite Battery Anode by Interfacial Stabilization (계면안정화를 통한 Si-SiO2-흑연 복합재 음극의 전기화학적 특성 개선)

  • Min, Jeong-Hye;Bae, Young-San;Kim, Sung-Su;Song, Seung-Wan
    • Journal of the Korean Electrochemical Society
    • /
    • v.15 no.3
    • /
    • pp.154-159
    • /
    • 2012
  • Structural volume change occurring on the Si-based anode battery materials during alloying/dealloying with lithium is noticed to be a major drawback responsible for a limited cycle life. Silicon monoxide has been reported to show relatively improved cycling performance compared to Si-containing materials for rechargeable lithium batteries, due to the structural buffering role of in-situ formed $Li_2O$ and lithium silicate during the reaction of silicon monoxide and lithium. Here we report improved cycling ability of interfacially stabilized Si-$SiO_2$-graphite composite anode using silane-based electrolyte additive for rechargeable lithium batteries, which includes low cost silicon dioxide for structural stabilization and graphite for enhanced conductivity.

Electrodeposition of SnS Thin film Solar Cells in the Presence of Sodium Citrate

  • Kihal, Rafiaa;Rahal, Hassiba;Affoune, Abed Mohamed;Ghers, Mokhtar
    • Journal of Electrochemical Science and Technology
    • /
    • v.8 no.3
    • /
    • pp.206-214
    • /
    • 2017
  • SnS films have been prepared by electrodeposition technique onto Cu and ITO substrates using acidic solutions containing tin chloride and sodium thiosulfate with sodium citrate as an additive. The effects of sodium citrate on the electrochemical behavior of electrolyte bath containing tin chloride and sodium thiosulfate were investigated by cyclic voltammetry and chronoamperometry techniques. Deposited films were characterized by XRD, FTIR, SEM, optical, photoelectrochemical, and electrical measurements. XRD data showed that deposited SnS with sodium citrate on both substrates were polycrystalline with orthorhombic structures and preferential orientations along (111) directions. However, SnS films with sodium citrate on Cu substrate exhibited a good crystalline structure if compared with that deposited on ITO substrates. FTIR results confirmed the presence of SnS films at peaks 1384 and $560cm^{-1}$. SEM images revealed that SnS with sodium citrate on Cu substrate are well covered with a smooth and uniform surface morphology than deposited on ITO substrate. The direct band gap of the films is about 1.3 eV. p-type semiconductor conduction of SnS was confirmed by photoelectrochemical and Hall Effect measurements. Electrical properties of SnS films showed a low electrical resistivity of $30{\Omega}cm$, carrier concentration of $2.6{\times}10^{15}cm^{-3}$ and mobility of $80cm^2V^{-1}s^{-1}$.

Effect of M2O3 on the Sinterbility and Electrical Conductivity of ZrO2(Y2O3) System(III) : Ceramics of the ZrO2-Y2O3-Ln2O3 System (ZrO2(Y2O3)계 세라믹스의 소결성과 전기전도도에 대한 M2O3의 영향(III) : ZrO2-Y2O3-Ln2O3계 세라믹스)

  • 오영제;정형진;이희수
    • Journal of the Korean Ceramic Society
    • /
    • v.24 no.2
    • /
    • pp.123-132
    • /
    • 1987
  • Yttria-stabilized zirconia with erbia-lanthana were investigated with respect to the amount of Ln2O3 (Ln; Er, La) addition in the range of 0.5∼5 mol% to the base composition of 8 mol% yttriazirconia. Following analysis and measurement were adopted for the characterization of synthesizes of solid electrolyte; phase transformation, lattice parameter, crystallite size, relative density, chemical composition and SEM/EDS. Electrical conductivity by two-probe method versus temperature from 350$^{\circ}C$ to 800$^{\circ}C$ and frequency in the range of 5Hz∼13MHz by complex impedance method was also conducted together with the determination of oxygen ion transference number by EMF method for the evaluation of their electrical properties. The results were as followsing; Electrical conductivity were decreased with increase in Ln2O3 content, but their activation energies increased. In the case of La2O3 addition, espicially, its electrical conductivity was decreased owing to the segregation of second phases at the grain-boundary. Grain-boundary conductivity of the specimen contained 0.5 mol% Er2O3 exhibited a maximum conductivity among thecompositions experimented. However, their bulk conductivities decreased in both case. Oxygen ion transference number was also reduced with decrease in oxygen partial pressure. For example, in the case of Er2O3 addition it retained value in the range of 0.97∼0.94 abvove 4.74${\times}$10-2in oxygen partial pressure. With the increase in the quantities of the evaporation of additive components, the crystallite size of stabilized zirconia decreased, and their relative density also reduced owing to the formation of porosity in their matrices. In the case of La2O3 the sinterbility was improved in the limited amount of addition up to 0.5 mol%, in the same range of addition the strength of sintered bodies were improved perhaps owing to the precipitation of metastable tetragonal phase in the fully stabilized zirconia.

  • PDF

Fabrication of Nano $Y_{2}O_{3}-CeO_{2}$ Sintered Body Using Dispersion Stability (분산 안정성을 이용한 나노 $Y_{2}O_{3}-CeO_{2}$ 소결체의 제조)

  • Kim, Eun-Jung;Lee, Sang-Hoon;Choi, Sung-Churl
    • Journal of the Korean Ceramic Society
    • /
    • v.38 no.9
    • /
    • pp.853-859
    • /
    • 2001
  • The dispersion stability of nano $Y_2O_3-CeO_2$ system was investigated using colloid surface chemistry. Green body of $Y_2O_3$ doped $CeO_2$ was prepared by slip casting in and aqueous system. The dispersion stability of suspension between powders and organic additive was accomplished through electrokinetic behavior of suspension, which was done by ESA apparatus. The dynamic mobility of particles was enhanced when the anionic dispersant of the amount of 1wt% was added. The dissolution of $Y^{3+}$ ion in suspension occurred in the acidic region so that pH value in slurries did not move to below 7.0. In the $CeO_2-Y_2O_3$ system, optimal preparation of suspension was made after adding the anionic dispersant as the amount of 1wt% and pH value of 11.0, and then slip-cast and sintered at 1400$^{\circ}$C, 2 hrs. It appeared relative density of >98% and homogeneous distribution of Y element in depth direction as well as in the microstructure of surface.

  • PDF

Effect of the particle size on the electrical contact in selective electro-deposition of copper (구리의 선택적 전착에서 결정 입자의 크기가 전기적 접촉성에 미치는 영향)

  • Hwang, Kyu-Ho;Lee, Kyung-Il;Joo, Seung-Ki;Kang, Tak
    • Journal of the Korean Crystal Growth and Crystal Technology
    • /
    • v.1 no.2
    • /
    • pp.79-93
    • /
    • 1991
  • With the advent of ULSI, many problems in previous metallization techniques and interconnection materials have become more serious. In this work, selective deposition of copper to fill the submicron contact has been tried. After forming electro-deposited copper films on p-type (100) silicon wafer using 0.75M $CuSO_4{\cdot}$5H_2O$ as an electrolyte, the effect of deposition time, current density and concentration of an additive on film properties were investigated. Film thickness, particle size and resistivity were analyzed by Alpha Step, SEM and 4 - point probe measurement respectively. The deposition rate was about $0.5-0.6\mu\textrm{m}$/min at $2A/dm^2$ and the particle size increased with increasing current density. The resistivities of electro-deposited copper films were about $3-6{\mu}{\Omega}{\cdot}$cm for the particle size above $4000{\AA}$. By the addition of 0.2 g/l gelatin, the particle size was reduced to less than $0.1{\mu}m $ and selective plugging of copper on submicron contacts could be successfully achieved.

  • PDF