Authors: Kenichi Myoujin, Takashi Ogihara, Koji Nakane, Nobuo Ogata
Abstract: Spherical Li[Ni(1/3-x)Mn(1/3-x)Co(1/3-x)Mx]O2 (M=Fe, Mg, Al) precursor powders were synthesized by
ultrasonic spray pyrolysis using aqueous solution of metal nitrate. X-ray diffraction (XRD),
scanning electron microscope (SEM), BET method using N2 adsorption analysis and Battery tester
were used for determination of the composition, morphology, particle size, surface area and
electrochemical properties. SEM observation showed that the size of as-prepared particles were
about 0.9 μ with narrow size distribution. The crystal phase of Li[Ni(1/3-x)Mn(1/3-x)Co(1/3-x)Mx]O2
(M=Fe, Mg, Al) was resulted in layered rock salt structure with R3m space group by calcinations at
1023 K for 10 h. No impurity-related peaks are observed from the XRD pattern with various doping
metals. Mg and Al doped Li(Ni1/3Co1/3Mn1/3)O2 showed very good cycling stability. The Mg
substitution for Ni led to the most excellent. On the other hand, the capacity degradation during
cycling was observed by Fe substitution for Mn doped Li(Ni1/3Co1/3Mn1/3)O2.
203
Authors: Takayuki Kodera, Takashi Ogihara, Nobuo Ogata, Koji Nakane, Ryo Yoshida, Suetaka Omura, Masao Uede
Abstract: BaTiO3 nano-sized powders were successfully prepared by spray pyrolysis using multiphase
plasma under the air atmosphere. The particles characteristics of BaTiO3 nano-sized powders were
studied by SEM and XRD. The effect of volume of arc plasma and precursor solution on the
formation of BaTiO3 nano-sized powders was investigated. The use of Ba-Ti complex precursor
solution derived from lactic acid led to formation of tetragonal BaTiO3 nano-sized powders with
140 nm size. As for BaTiO3 ceramics, the effect of sintering temperature on relative density and the
temperature dependence of dielectric properties were investigated.
35
Authors: Kenichi Myoujin, Takashi Ogihara, Nobuo Ogata, Koji Nakane, Takayuki Kodera, Suetaka Omura, Masao Uede, Kazuya Higeta
Abstract: Spherical LiNi1/3Mn1/3Co1/3O2 precursor powders were synthesized by aerosol plasma pyrolysis
using aqueous solution of metal nitrate. XRD, SEM, TEM and BET analysis were used for determi-
nation of the composition, morphology, particle size and surface area. SEM observation showed
that the size of as-prepared particles were about 200 nm. The value of geometrical standard
deviation (σg) calculated from the particle size distribution was 1.20, suggesting that the particle
size distribution was narrow. The crystal phase of LiNi1/3Mn1/3Co1/3O2 was resulted in layered
rock salt structure with R3m space group. The rechargeable capacity of LiNi1/3Mn1/3Co1/3O2 was
about 142-175 mAh/g. The discharge capacity of LiNi1/3Mn1/3Co1/3O2 decreased with increasing
cycle number. However, the cycling stability of Li(Ni1/3Mn1/3Co1/3)O2 powders that aerosol plasma
pyrolysis process offered superior performance to ultrasonic spray pyrolysis process.
255
Authors: Hajime Horikawa, Takashi Ogihara, Nobuo Ogata, Masahiro Asahara, Xing Zheng Wu
Abstract: Titania nanocrystals were prepared by hydrolysis of titanium alkoxide in ethanol solution. The
preparation of titania / alumina thin film was performed on ITO coated glass substrate by dip
coating method using ethanol of titania nanocrystal and boemite sol. The crystal structures,
microstructure and thickness of titania / alumina thin film were examined by XRD and SEM. The
adsorption of dye was influenced by the surface structure of thin film. The adsorption of dye on the
films was improved by the immersion into acid as HNO3. Ruthenium polypyridyl complex and
triarylmethylium salt were used as dye. Electrode using titania / alumina thin film for dye-sensitized
solar cell was constructed.
231
Authors: Takayuki Kodera, Hajime Horikawa, Takashi Ogihara, Nobuo Ogata, Koji Nakane, Suetaka Omura, Masao Uede, Kazuya Higeta, Susumu Hiyama
Abstract: Homogeneous BaTiO3 nano-sized powders were successfully prepared by spray pyrolysis
using multiphase plasma under the air atmosphere. Particle size, morphology, crystal phase
and crystallinity of as-prepared powders were characterized by SEM and XRD. The effect
of starting precursor solution on the formation of nanoparticles was investigated. The use
of Ba/Ti aqueous solution derived from malic acid led to formation of cubic BaTiO3
nanoparticles with 50 nm size.
135
Authors: Izumi Mukoyama, Takayuki Kodera, Nobuo Ogata, Takashi Ogihara
Abstract: LiM(M=Fe,Al,Mg)XMn2-XO4 fine powders were synthesized by the ultrasonic spray pyrolysis using metal nitrate solution. LiMn2O4 powders obtained by this method have a spherical morphology with a submicron size. XRD revealed that as-prepared powders were crystallized to spinel structure with Fd3m space group. LiM(M=Fe,Al,Mg)XMn2-XO4 showed enhanced cycling performance at room temperature. Reduced Jahn-Teller distortion of LiMn2O4 by metal doping was responsible for enhanced cycle performance of LiMn2O4.
167
Authors: Kenichi Myoujin, Nobuyoshi Aoyagi, Nobuo Ogata, Takashi Ogihara
Abstract: Spherical La0.8Sr0.2Ga0.8Mg0.2O2.8 precursor powders were synthesized by ultrasonic spray pyrolysis using aqueous solution of citric acid and of metal nitrate. As-prepared powders obtained by this method have a spherical morphology with a submicron size. The calcination behavior of the precursor powders of the above phases were examined in the temperature range of 1073 –1773 K in an air atmosphere. XRD, SEM, DTA-TG and BET analysis were used for determination of the composition, morphology, particle size and surface area. XRD revealed that as-prepared powders were crystallized to perovskite structure after the sintering at 1573 K for 10 h.
163
Authors: Nobuyoshi Aoyagi, Takashi Ookawa, Ryousuke Ueyama, Takashi Ogihara, Nobuo Ogata
187
Authors: Hitoshi Aikiyo, Koji Nakane, Nobuo Ogata, Takashi Ogihara
131
Authors: Kenichi Myoujin, Koji Nakane, Takashi Ogihara, Nobuo Ogata
31