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The highly porous LSC/GDC composites were fabricated and characterized as a potential air side current collecting material for micro-tubular SOFCs. The results revealed that the properties of the composites were strongly affected by the composition, particle size ratio of starting powders, microstructure and porosity. The composite specimen with 35 vol. % GDC and an open porosity of 73% gave an electrical conductivity of 174 S/cm at 600 ºC, which is 1.8 times as large as that of the LSCF with a porosity of 61%, and a thermal expansion coefficient of 12.6×10-6 K-1 in the temperature range from room temperature to 600 ºC, which is very close to the value of the LSCF cathode. The superior combined property suggests the possibility that they serve as air side current collectors in the micro-tubular SOFCs.

A series of LSC/CeO2 composites were prepared as potential air side current collecting materials for micro-tubular SOFCs and their properties were examined and discussed in relation with the composition, microstructure and porosity. The results revealed that the composite specimen with 35 vol.% CeO2 and an open porosity of 73% gave a electrical conductivity of 130 S/cm at 600 ºC, which was 1.4 times as that of the LSCF with a porosity of 61%, and a thermal expansion coefficient of 12.2×10-6 1/ºC between room temperature and 600 {degree sign}C, which was almost the same as that of the LSCF cathode. The composite specimen also demonstrated good stability during a long-term test, suggesting the possibility that they serve as air side current collectors in the micro-tubular SOFCs.

A Ni-GDC cermet is expected as one of the materials for lower temperature SOFC anode, which is obtained from reducing NiO-GDC powder. In this work, we report the effects of NiO-GDC powders produced by mechano-chemical technique on the fabricating processes of anode and the electrical performance of the anode. The properties of sintering and dispersion of NiO-GDC powders were studied and the morphology of Ni-GDC anode was characterized. The performance of the cell which consisted of Ni-GDC anode, GDC electrolyte and LSCF cathode was evaluated by current interruption method. The experimental results indicated that the maximum power densities were 0.93 and 0.31 W/cm2 when the cell was operated at 600{degree sign}C and 500{degree sign}C respectively.

The electrode performance of a single solid-oxide fuel cell (SOFC) was evaluated using a 500 {micro}m thick La{sub 0.9}Sr{sub 0.1}Ga{sub 0.8}O{sub 0.3} (LSGM) as the electrolyte membrane. A doped lanthanum cobaltite, La{sub 0.6}Sr{sub 0.4}CoO{sub 3{minus}{delta}} was selected as the cathode material, and a samaria-doped ceria-NiO composite powder was used as the anode material. The spray-pyrolysis method was applied for synthesis of the starting powders of the cathode and anode. In this study, different microstructures of the cathode were obtained by varying the sintering temperature from 950 to 1200 C. High power density (the maximum power density of the cell was about 425 mW/cm{sup 2}, which is 95% of the theoretical value) of the solid oxide fuel cell at 800 C was achieved. The cell performance showed that, with a proper choice of electrode materials with optimized microstructure and LSGM as the electrolyte, a SOFC operating at temperatures T{sub op} {le} 800 is a realistic goal.

Much attention has been payed to lithium metal silicate (Li2MSiO4, M=Fe and Mn) as a promising cathode of large-scale lithium ion battery which can be used in electric vehicles and renewable energy generation systems. The Li2MSiO4, however, has a disadvantage in electronic conduction: their electrical conductivities are below 10-14 S/cm, which are much lower than those of LiCoO2. In addition, the diffusivity of lithium ion in the Li2MSiO4 is low compared with that in LiCoO2. Two approaches have been proposed for improvement in the conduction properties of Li2MSiO4: one is addition of conductive carbon, and the other reduction of particle size. Although various processes including use of expensive graphene and carbon nano-tube have been reported to obtain high capacity Li2MSiO4/carbon composite fine powders, it is important to develop cost-effective processes for broad commercial applications of the lithium ion batteries. The authors have applied spray-frozen/freeze-drying (SF/FD) process to preparation of Li2MSiO4/carbon composite fine powders. The SF/FD is a practical process based on combination of spray-drying and freeze-drying processes, leading to ceramic fine powders with large specific surface area in high purity. In this study, Li2FeSiO4/carbon composite powder was prepared by SF/FD of solutions containing carbon sources followed by heat-treatment in flowing argon. Indian ink and glucose was added as the carbon sources. High capacity of 255 mAh/g was obtained at an initial discharge for the as-prepared Li2FeSiO4/carbon composite cathode powders even though any conductive additives were not added to the composite powders thus prepared. The Li2FeSiO4 showed high value of 173 mAh/g even after ten cycles of charge/discharge. This result indicates that most of Li2FeSiO4 particles are connected with carbon network from the starting carbon sources. The capacity at an initial discharge was increased to 323 mAh/g by adding an amount of Ketjenblack to the composite powder. The value became 238 mAh/g after ten cycles. TEM observations revealed that most of Li2FeSiO4 particles had size of 30-50 nm and the nano-Li2FeSiO4 particles were homogeneously complexed with colloidal carbons from Indian ink. In addition, it was observed that the nano-Li2FeSiO4 particles were coated with carbon layer with about 2 nm in thickness. Thus, homogeneous composites of Li2FeSiO4 and carbon nano-particles were successfully prepared by SF/FD of the solutions containing two kinds of carbon sources, leading to high cathode performance. These results clearly indicate that the practical SF/FD process can be applied for preparation of high capacity Li2FeSiO4/carbon composite cathode powder.

The authors have developed the continuous kneading process for lithium ion battery (LIB) slurry to prepare for future mass production and cost reduction. It is very important operation in a battery manufacturing process to disperse electrode materials because battery performance is decided by the dispersion states of electrode materials. A batch operation is generally used as a conventional method, and it needs long operation time to make dispersion slurry. Getting dispersion slurry using some of the next generation active materials having modified-surface and fine grain size is difficult for the conventional method. To provide a dispersing device capable of efficiently obtaining dispersion force is required. We use twin screw type continuous kneading machine. This continuous kneader can disperse a wide range of viscosity. The continuous kneader is also applied in various industries such as food and chemical in order to have excellent dispersing ability. Due to continuous process, automation and cost reduction become possible, and production speed is improved. The continuous kneader is closed horizontal twin screw type. The twin screws are constructed of many paddles which are mounted on the twin shafts. Each paddle is separate piece that can be arranged to suit various mixing characteristics. The shafts rotate in the same direction. The paddles are arranged in pairs along the mixing circuit, and have a constant clearance between the tip of the paddle and the inner barrel wall, as well as the tip of the paddle to the surface of the opposite piece. This gives the benefit of mixing efficiency. Volume of material is changed in compression and expansion according to paddle's rotation. Shearing actions between the barrel and paddle, and between paddles increases efficiency of kneading and dispersion. The continuous kneader was applied to the tape for manufacturing magnetic recording medium, because dispersion plays important role. The magnetic powder became finer according to enhance data capacity, the continuous kneader could manufacture good dispersion magnetic coating material in response to this change. Manufacturing of lithium ion battery electrode slurry is kneading powder materials in binder resin in the similar way of making the magnetic tape. The authors included the know-how obtained by improving manufacturing of the magnetic tape in continuous kneading process of lithium ion battery electrode slurry. The authors have performed examination of suitable kneading conditions of dispersion slurry production by using Li(Ni1/3Mn1/3Co1/3)O2 (NMC) and LiFePO4(LFP) as cathode active materials. The dispersion state of the slurry using the continuous kneader is controlled by the paddle arrangement, the rotary speed of the shaft and the supply conditions of raw materials. Several elements of kneading conditions have beneficial effect on slurry viscosity and battery performance. After changing some of kneading conditions, excellent dispersion slurries were obtained. The slurry from optimized continuous process showed high battery performance. Cyclic performance of laminated pouch type cell showed a stable characteristic about 2,000 cycles at the charge-discharge rate of 3C. The battery performance was comparison with the slurry made by using batch operation. Rate characteristics and cyclic performance of the slurry made by continuous kneading process showed better than made by batch operation. The paddle arrangement and the supply conditions of raw materials influence the dispersion state of slurry. The solid content concentration in the continuous kneader changes when supply conditions of raw materials was changes, it was considered that the dispersion of raw materials advanced by adjusting the solid content concentration appropriately. This high speed continuous kneading process greatly improves not only the battery performance but also productivity of the electrode slurry. Our high speed continuous kneading process can manufacture about 60 times faster than the conventional batch operation according to our estimates. Therefore the cost reduction may be practiced in LIB mass production. The above-mentioned results indicate that the high speed process of high performance electrode slurry made by the continuous kneader is effective method. Figure 1

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The performance of a Sr- and Mg- doped lanthanum gallate (LSGM) electrolyte based solid oxide fuel cell is greatly affected by the interfacial reaction of electrode material with the LSGM electrolyte. The reactivity is closely related to the electrode composition and the sintering temperature. The ohmic loss is a good indicator of the reactivity (i.e., an overly-high and unequal ohmic loss between the anodic and the cathodic). The interfacial reaction also interferes with the measurement of the electrode overpotential. Care should be taken in the interpretation of measured electrode overpotentials if an interfacial reaction occurs in the cell.

Electrophoretic deposition (EPD) was used for the fabrication of anode-supported yttria-stabilized zirconia (YSZ) electrolyte films. For the EPD, thin layers of graphite were pre-coated on the surface of a nonconducting porous NiO-YSZ composite anode substrate. Uniform YSZ green films were formed on the reverse sides, which did not have the graphite layers. The specimens were transformed into dense bodies ∼5 to 10 μm thick after being co-fired with the substrates. The cell performance of the ∼5 μm thick dense YSZ films supported on the anode substrates was tested using a La(Sr)Co(Fe)O 3 cathode. Maximum output power densities of ∼0.19, ∼0.61, and ∼1.02 W/cm 2 were attained at 600, 700, and 800°C, respectively.