oalib
Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
Synthesis of Ba0.5Sr0.5Co0.2Fe0.8O3 (BSCF) Nanoceramic Cathode Powders by Sol-Gel Process for Solid Oxide Fuel Cell (SOFC) Application  [PDF]
Mohammad Ghouse, Yousef M. Al-Yousef
World Journal of Nano Science and Engineering (WJNSE) , 2011, DOI: 10.4236/wjnse.2011.14016
Abstract: The nano ceramic Ba0.5Sr0.5Co0.2Fe0.8O3 (BSCF) powders have been synthesized by Sol-Gel process using nitrate based chemicals for SOFC applications since these powders are considered to be more promising cathode materials for SOFC. Glycine was used as a chelant agent and ethylene glycol as a dispersant. The powders were calcined at 850℃/3 hr in the air using Thermolyne 47,900 furnace. These powders were characterized by employing SEM/EDS, XRD and TGA/DTA techniques. The SEM images BSCF powder indicate the presence of highly porous spherical particles with nano sizes. The XRD results shows the formation of BSCF perovskite phase at the calcination temperature of 850℃. From XRD line broadening technique, the average crystllite size of the BSCF powders were found to be around 9.15 - 11.83 nm and 13.63 - 17.47 nm for as prepared and after calcination at 850℃ respectively. The TGA plot shows that there is no weight loss after the temperature around 450℃ indicating completion of combustion.
Preparation of La0.6Ba0.4Co0.2Fe0.8O3 (LBCF) Nanoceramic Cathode Powders by Sol-Gel Process for Solid Oxide Fuel Cell (SOFC) Application  [PDF]
Y. M. Al-Yousef, M. Ghouse
Energy and Power Engineering (EPE) , 2011, DOI: 10.4236/epe.2011.33049
Abstract: The La0.6Ba0.4Co0.2Fe0.8O3 (LBCF) nano ceramic powders were prepared by Sol-Gel process using nitrate based chemicals for SOFC applications since these powders are considered to be more promising cathode materials for SOFC. Citric acid was used as a chelant agent and ethylene glycol as a dispersant. The powders were calcined at 650oC/6 h, 900oC/3 h in air using Thermolyne 47,900 furnace. These powders were charac terized by SEM/EDS, XRD and Porosimetry techniques. The SEM images indicate that the particle sizes of the LBCF powders are in the range of 50 - 200 nm. The LBCF perovskite phases are seen from the XRD patterns. From XRD Line broadening technique, the average particle size for the powders (as prepared and calcined at 650oC/6 h and 900oC/3 h) were found to be around 12.97 nm, 22.24 nm and 26 nm respectively. The surface area of the LBCF powders for the as prepared and calcined at 650oC were found to be 28.92 and 19.54 m2/g respectively.
Electrochemical performances of BSCF cathode materials for ceria-composite electrolyte low temperature solid oxide fuel cells
Xueli Sun, Song Li, Juncai Sun, Xiangrong Liu, Bin Zhu
International Journal of Electrochemical Science , 2007,
Abstract: The Ba0.5Sr0.5Co0.2Fe0.8O3 (BSCF) cathode material was synthesized and evaluated for cathode in low temperature solid oxide fuel cells (LTSOFCs). Using Ni as anode, Sm0.2Ce0.8O2(SDC)-carbonate composites as electrolyte and the BSCF as cathode to construct the fuel cell (LTSOFC), maximum power output of 860 mW/cm2 has been achieved at 500 oC. The LTSOFC at a large area, 14 cm2, has delivered 5 W corresponding to a power density of 358 mW/cm2 at 510 oC. These results have been the first recorded for the best performance of SOFCs at low temperatures.
Crystal Structure and Ionic Conductivity Study of Ni- Doped BSCF Cathode for Low Temperature SOFCS  [PDF]
Suman Kumar Burnwal
Bonfring International Journal of Industrial Engineering and Management Science , 2013, DOI: 10.9756/bijiems.4192
Abstract: Nickel doped BSCF (Ba0.5Sr0.5Co1-xFe0.6NixO3-δ (BSCFNi); x=0.05, 0.1, 0.15, and 0.2) cathode materials were synthesized using sol-gel citrate method for low temperature (300-500oC) Solid Oxide Fuel Cell (SOFC) application. The nanopowders of BSCFNi were then calcinated at various temperatures in the range of 600-1000oC. The nanopowders were characterized using X-ray diffraction (XRD), scanning electron microscope (SEM) and differential scanning calorimeter (DSC). A cubic perovskite structure was observed in the X-ray diffraction measurements. The average crystallite size of the nanopowder obtained varies between 40-60 nm. DSC result, measured in the temperature range of 200-600oC, shows no phase transition. Ionic conductivity of the BSCFNi for varying concentration of nickel was measured in the temperature range of 200 oC to 500 oC. An emphasis is made on the effect of Ni doping on these properties.
Preparation and Characterization of Pr2-xSrxCoO4+δ Cathode Materials for IT-SOFC
CAO Yue, GU Hai-Tao, CHEN Han, ZHENG Yi-Feng, ZHOU Ming, GUO Lu-Cun
无机材料学报 , 2003, DOI: 10.3724/sp.j.1077.2010.00738
Abstract: The samples of Pr2-xSrxCoO4+δ (x=0.8, 1.0, 1.2) as cathode material for intermediate-temperature solid oxide fuel cell (IT-SOFC) were synthesized by solid-state reaction. Crystal structure, thermal expansion, electrical conductivity and electrochemical properties were investigated by XRD, SEM, dilatometry, DC four-probe method, AC impedance and cyclic voltammetry (CV) techniques, respectively. The XRD results showed all the samples obtained as a single K2NiF4-structural phase, there were no chemical reaction occurred between the Pr0.08Sr1.2CoO4+δ electrode and the Sm0.2Ce0.8O1.9 (SDC) electrolyte at 1100℃ in air. The thermal expansion coefficients (TECs) increased with Sr content increasing. The electrical conductivity of the specimens was over 100S/cm at 800℃. The polarization resistance decreased with the increasing of Sr content. Pr0.8Sr1.2O4+δ had the optimum value of 0.29Ω·cm2 at 700℃ in air.
Electrocatalytic Reduction of Oxygen at Perovskite (BSCF)-MWCNT Composite Electrodes  [PDF]
Farhanini Yusoff, Norita Mohamed, Azizan Aziz, Sulaiman Ab Ghani
Materials Sciences and Applications (MSA) , 2014, DOI: 10.4236/msa.2014.54025
Abstract:

A composite paste electrode based on Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF)—initially synthesized by solgel method—and multiwall carbon nanotube (MWCNT) as a cathode in fuel cells is developed. The composite pastes are prepared by the direct mixing of BSCF:MWCNT at 90:10, 80:20 and 70:30 (% w/W). These electrodes are then characterized by the x-ray diffraction (XRD), scanning electron microscopy (SEM), nitrogen adsorption-desorption isotherm, electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The XRD and SEM confirm the inclusion and the uniform dispersal of the MWCNT within BSCF, respectively. The nitrogen adsorption isotherm study shows that the porosity of the composite paste electrode has been improved by two-fold from the BSCF electrode. The EIS and CV demonstrate that the higher ratios of MWCNT in the composites are critical in improving the electronic conductivity as well as the kinetics. It is also noticeable that the electrode has increased the catalysis of oxygen in 0.1 M KOH (pH 12.0). Cyclic voltammetric studies on the oxygen reduction reaction (ORR) suggest that the incorporation of MWCNT is vital in improving the electrode (cathode) properties of a fuel cell.

Mass Production of LiFeP /C Powders by Large Type Spray Pyrolysis Apparatus and Its Application to Cathode for Lithium Ion Battery  [PDF]
Shinsuke Akao,Motofumi Yamada,Takayuki Kodera,Takashi Ogihara
International Journal of Chemical Engineering , 2010, DOI: 10.1155/2010/175914
Abstract: Spherical LiFeP /C powders were successfully produced at a rate of 100?g/h using a large type spray pyrolysis apparatus. Organic compounds such as citric acid and sucrose were used as carbon sources. Scanning electron microscopy observation showed that they had a spherical morphology with nonaggregation. X-ray diffraction analysis revealed that the olivine phase was obtained by heating at under argon (95%)/hydrogen (5%) atmosphere. The chemical composition of LiFeP /C powders was in good agreement with that of the starting solution. Electrochemical measurement revealed that the use of citric acid was most effective in ensuring a high rechargeable capacity and cycle stability. The rechargeable capacity of the LiFeP /C cathode obtained using citric acid was 155?mAh/g at a discharge rate of 1?C. Because of the good discharge capacity of the LiFeP /C cathode, it exhibited excellent cycle stability after 100 cycles at each discharge rate. Moreover, this high cycle stability of the LiFeP /C cathode was maintained even at . 1. Introduction Recently, olivine-type LiFePO4 has been considered as a suitable cathode material for lithium-ion batteries used in EVs (electric vehicles), HEVs (hybrid electric vehicles), and power supplies used for load leveling in wind power generation and solar power generation. [1, 2]. Olivine-type LiFePO4 exhibits a relatively high theoretical capacity of 170?mAh/g and a stable cycle performance at high temperatures. However, in the past, the low electrical conductivity of LiFePO4 prevented its application as a cathode material for the lithium-ion battery. Therefore, conductive materials such as carbon and metals were added to LiFePO4 in order to enhance its electrical conductivity [3–6]. Yang et al. reported the electrochemical properties of LiFePO4/C cathode materials prepared by spray pyrolysis [7]. The advantages of spray pyrolysis [8, 9] are as follows: (1) spherical and homogeneous oxide powders can be directly prepared, and the synthesis time is much shorter than that required for a solid-state reaction and the sol-gel method and (2) carbon or metal ions are directly doped to the particles in one step. We have synthesized various types of lithium oxide powders such as LiNiO2, LiMn2O4, and LiNi1/3Mn2/3O4 for the development of the lithium-ion battery by spray pyrolysis [10–12]. We found that by using the materials prepared by spray pyrolysis as cathode materials for the lithium-ion battery, the rechargeable capacity and cycle life of the battery were improved. It has been found clear that a LiFePO4/C cathode produced by spray
Strontium and iron-doped barium cobaltite prepared by solution combustion synthesis: exploring a mixed-fuel approach for tailored intermediate temperature solid oxide fuel cell cathode materials
Francesca Deganello,Leonarda F. Liotta,Giuseppe Marcì,Emiliana Fabbri,Enrico Traversa
Materials for Renewable and Sustainable Energy , 2013, DOI: 10.1007/s40243-013-0008-z
Abstract: Ba0.5Sr0.5Co0.8Fe0.2O3–δ (BSCF) powders were prepared by solution combustion synthesis using single and double fuels. The effect of the fuel mixture on the main properties of this well-known solid oxide fuel cell cathode material with high oxygen ion and electronic conduction was investigated in detail. Results showed that the fuel mixture significantly affected the area-specific resistance of the BSCF cathode materials, by controlling the oxygen deficiency and stabilizing the Co2+ oxidation state. It was demonstrated that high fuel-to-metal cations molar ratios and high reducing power of the combustion fuel mixture are mainly responsible for the decreasing of the area-specific resistance of BSCF cathode materials. Moreover, a new metastable monoclinic phase with Ba0.5Sr0.5CO3 composition was discovered in the as-burned BSCF powders, enlarging the existing information on the BSCF phase formation mechanism.
Synthesis of LiCopo4 Powders as a High-Voltage Cathode Material via Solvothermal Method  [PDF]
Jianhuang Ke, Yu Han, Kai Xie
Journal of Power and Energy Engineering (JPEE) , 2017, DOI: 10.4236/jpee.2017.512004
Abstract:
Lithium cobalt phosphate (LiCoPO4, LCP), having a high operating potential (4.8 V vs. Li/Li+), a flat voltage profile and a good theoretical capacity (167 mAh/g), is considered a promising cathode material for improving the energy density of lithium-ion batteries (LIBs) [1] [2]. Here we report a category of method for synthesizing LCP, the solvothermal (ST) method with a binary solvent (deionized water: ethyl alcohol = 1:1), controlling the concentration of cobalt ion in 0.05 mol/L (ST-0.05) and 0.25mol/L (ST-0.25). The material phase was apparently identified via X-ray diffraction (XRD). Observed by scanning electron microscopy (SEM), the grain size of LCP powders synthesizing by solvothermal method with two kinds of the concentration of cobalt ion were 400 × 400 × 1000 nm cuboids (ST-0.05) and 150 × 150 × 250 nm hexagonal prisms containing nanoparticles (ST-0.25), respectively. Discharge capacities of LCP were 76.0 mAh/g (ST-0.05) and 94.5 mAh/g (ST-0.25), in the first cycle at 0.1 C, respectively.
Review on Fabricating YSZ Electrolyte Film for SOFC
固体氧化物燃料电池YSZ电解质薄膜的制备方法概述

FAN Bao-an,ZHU Qing-shan,XIE Zhao-hui,
范宝安
,朱庆山,谢朝晖

过程工程学报 , 2004,
Abstract: Solid Oxide Fuel Cell (SOFC) is a promising technique for generating electricity with merits of high efficiency and low pollution. yttrium-stabilized zirconia (YSZ) is the most commonly used electrolyte material for SOFC. The preparation of high quality YSZ electrolyte film, thin but gas-tight, on porous cathode or anode is crucial to the fabrication of SOFC. This paper reviews several different methods for fabricating YSZ electrolyte film, which are generally classified as three groups: gas phase, liquid phase and solid phase methods. The advantages and disadvantages of each method and its application are discussed and then, the future development trends of fabricating YSZ electrolyte film for SOFC are analysed.
Page 1 /100
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.