Electrochemistry, Vol. 73. No.02, 2005


Positive Electrode Performance of Nonflammable Lithium Secondary
Battery with Ambient‐Temperature Molten Salt Electrolyte

Koichi UI, Kohei ISHIKAWA, Takao FURUYA,
Yasushi IDEMOTO, and Nobuyuki KOURA

Faculty of Science and Technology, Tokyo University of Science (2641 Yamazaki, Noda, Chiba 278‐8510, Japan)

Received September 21, 2004 ; Accepted November 29, 2004

The positive electrode performance of the LiCoO2 electrode in the LiCl saturated AlCl3‐1‐ethyl‐3‐methylimizadolium chloride (EMIC) + SOCl2 melt as the electrolyte for nonflammable lithium secondary batteries was evaluated. In the cyclic voltammogram of the LiCoO2 electrode in the melt, the oxidation and reduction waves corresponding to the electrochemical intercalation / deintercalation reactions of Li were observed at 3.5〜4.2V vs. Li/Li, and it suggested that the LiCoO2 electrode operated well in this melt. From charge and discharge evaluations, it was known that the discharge capacity was about 130mAh g−1 and the coulomb efficiency was maintained of more than 93% during ten cycles. It became clear that the LiCoO2 electrode operates quite as a positive electrode in the melt.


Autocatalytic Deposition of Pure Nickel Films Having Bright Surfaces
and High Electrical Conductivity

Kiyoshi ITO, Shinji YAE, Takahiro HAMADA, Hisatsugu NAKANO,
Naoki FUKUMURO, and Hitoshi MATSUDA

Department of Materials Science and Chemistry, Graduate School of Engineering, University of Hyogo (2167 Shosha, Himeji, Hyogo 671‐2201, Japan)

Received August 11, 2004 ; Accepted November 18, 2004

A solution has been developed for autocatalytic (electroless) pure Ni plating using hydrazine as a reducing agent that has three desired characteristics: high stability, a high deposition rate, and high deposit brightness. The solution components are nickel acetate, hydrazine, ethylenediaminetetraacetic acid, lactic acid, and boric acid. Saccharin sodium and formaldehyde are used as additives in some cases. The deposition rate and surface morphology of the films change with the composition of the plating solution. The deposition rate reaches 3.0 nm s−1. The brightness of the Ni films depends on the surface morphology. The reflectance of the deposited films at a wavelength of 550 nm changes from 0.6% (black) to 54%, the same level as autocatalytic Ni‐P alloy films. The total impurity content (C, N, B and S) of the deposited Ni films is less than 0.4 mass%. The lowest value of the total content is 0.12 mass%. Electrical conductivity increases with purity and reaches 11.3×106 S m−1, which is equivalent to pure Ni foil with a purity of 99.7%. The deposition rate, surface morphology, brightness, and electrical conductivity of autocatalytic pure Ni films can be controlled by changing the composition of the plating solution.


Microstructural Analyses of Ceria‐Based Anode
with Highly Dispersed Ni Electrocatalysts for
Medium‐Temperature Solid Oxide Fuel Cells

Shinsuke SUZUKI,a Hiroyuki UCHIDA,a* and Masahiro WATANABE b

aInterdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi (Kofu 400‐8511, Japan)
bClean Energy Research Center, University of Yamanashi (Kofu 400‐8510, Japan)

Received September 9, 2004 ; Accepted October 31, 2004

Mixed conducting samaria‐doped ceria (SDC) anodes with a small amount of Ni nanoparticles (8 vol.%) exhibited a higher performance in SOFC operated at 700‐900℃ than that of Ni‐SDC cermet. Microstructural analyses of Ni‐dispersed SDC showed that nanometer‐sized Ni catalysts enhanced the anodic reaction rate by increasing the active reaction sites and lowering the electronic resistance in the anode effectively. The Ni‐dispersed SDC anode exhibited a stable performance at 800℃ and 0.6 A cm−2 in humidified H2 for a long term over 1100 h.



小浦 延幸,粕谷 健太,宇井 幸一,滝口 友輝,井手本 康

東京理科大学理工学部(〒278‐8510 野田市山崎2641)

Corrosion Behavior of Pb Alloys as Negative Current Collector
for Lead Acid Batteries in Charged State

Nobuyuki KOURA, Kenta KASUYA, Koichi UI, Yuki TAKIGUCHI, and Yasushi IDEMOTO

Faculty of Science & Technology, Tokyo University of Science (2641 Yamazaki, Noda‐shi, Chiba 278‐8510, Japan)

Received July 23, 2004 ; Accepted November 13, 2004

The corrosion behavior of the exposed part of the Pb alloy negative electrode from the electrolyte was analyzed upon charging, i.e., under the reduced state. Dissolved oxygen in the electrolyte affected the generation rate and the grain size of the PbSO4. From the potential measurements at the exposed part, it was found that the part not under reducing conditions and the generation reaction of PbSO4 progressed by the local cell reaction. Furthermore, when the dissolved oxygen concentration in the electrolyte film on the exposed part increased, the potential at the exposed part became noble and the PbSO4 generation rate increased. On the other hand, the most anti‐corrosive Pb alloy was the Pb‐1.8%Sn‐0.03%Se alloy. The reason was attributed to the dense corrosion layer formed on the surface, because the PbSO4 grain size became small by the synergistic effect of Sn and Se.



北折 典之,高橋 三男

東京工業高等専門学校物質工学科(〒193‐0997 八王子市椚田町1220‐2)

Improvements in the Sterilization Performance of Sodium Hypochlorite

Noriyuki KITAORI  and Mitsuo TAKAHASHI

Department of Chemical Science and Engineering, Tokyo National College of Technology (1220‐2 Kunugida‐cho, Hachioji, Tokyo, 193‐0997, Japan)

Received September 2, 2004 ; Accepted November 11, 2004

Sodium hypochlorite solution is one of the most useful and important sterilizers. It has high sterilizing power even in low concentrations and with various bacteria. In addition, the risk for the human body is low and the preparation cost is cheap. However its weak point is that it's sterilizing power for the spores of Bacillus cereus is very low. Improvements in the sterilization performance of Sodium hypochlorite for the spore have been investigated. Two methods for killing the spore have been found. The technical methods are as follows (1) the spore of Bacillus cereus can be destroyed by accelerating the evolution of the hydroxyl radical by adding Fe2+ as a reducing agent (same as Fenton's reagent) and (2) by non‐ionization of NaOCl by including NaCl to be the strong electrolyte in the Sodium hypochlorite solution. As a result, the sterilizing properties of the Sodium hypochlorite solution by improved six orders of magnitude and had the same performance as HOCl by non‐ionization of NaOCl by adding NaCl.



和田知恵子,阿相 英孝,小野 幸子

工学院大学工学部応用化学科(〒163‐8677 東京都新宿区西新宿1‐24‐2)

Effect of Current Density on the Film Thickness and Structure
of Anodic Barrier Films Formed on Aluminum at Low Voltage Region

Chieko WADA, Hidetaka ASOH, and Sachiko ONO 

Department of Applied Chemistry, Faculty of Engineering, Kogakuin University (1‐24‐2, Nishi‐shinjuku, Shinjuku‐ku, Tokyo 163‐8677, Japan)

Received September 13, 2004 ; Accepted November 1, 2004

The differences in properties of anodic films formed on aluminum in ammonium adipate solution at low voltage and high voltage were clarified by investigating the relation between current density and the thickness which was evaluated by voltage jump at re‐anodizing of anodized specimen. The film thickness formed at constant current density up to 80V decreased with increasing current density. The film thickness had liner relation with log of current density. This liner relation could be ascertained for all the films formed even at low voltages such as 5V when Galvano‐static polarization measurement was applied to avoid iR‐drop caused by solution resistance. The thickness became the same value after 20min sustaining of anodizing voltage accompanied by current decay. Furthermore, it was confirmed that the film thickness was determined by final current density during anodizing.

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