Online ISSN : 2186-2451
Print ISSN : 1344-3542
ISSN-L : 1344-3542
Volume 76 , Issue 9
Showing 1-13 articles out of 13 articles from the selected issue
  • Takahisa IIDA, Tomoki HIRONO, Natsumi SHIBAMURA, Hiroki SAKAGUCHI
    2008 Volume 76 Issue 9 Pages 644-648
    Published: September 05, 2008
    Released: March 22, 2012
    Mg2Ge/Si composite electrodes were prepared by a gas-deposition (GD) method and evaluated their electrochemical properties of anodes for Li rechargeable battery. The discharge capacity of the Mg2Ge/Si composite electrodes increased in comparison with that of Mg2Ge GD-film electrode. Among them, the Mg2Ge/Si composite electrode with 30 wt% Si content exhibited good cycle stability, which is 603 mAh g−1 after 200 cycles. At this composition of composite, each Si particle was surrounded with Mg2Ge layer, and the Mg2Ge layer appears to be easy to release the stress generated in the Si particle at Li insertion-extraction because Mg2Ge is more ductile than Si. Thus, we succeeded to develop the electrode which can take advantage of both high capacity of Si and good cyclability of Mg2Ge.
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    2008 Volume 76 Issue 9 Pages 649-655
    Published: September 05, 2008
    Released: March 22, 2012
    The extra positive electrode of an EDLC where doesn’t face to a negative electrode was known as an easily corroded area. However, the mechanism was not clear. In this paper, in order to simulate an extra positive electrode, two sets of EDLC (Cell 1 and Cell 2) were arranged in a horizontal plane, and the positive electrode of Cell 1 (P1) and that of Cell 2 (P2) were connected or disconnected electrically. Four reference electrodes were embedded around Cell 1 and Cell 2 and electrical potential behavior in a horizontal plane of an EDLC twin cell was studied. With the extra positive electrode (P2), P2 potential shifted to high when charging and discharging the Cell 2, and electric current flow of several mA was observed between P1 and P2. By a simulation study of an electric equivalent circuit of an EDLC twin cell, an ionic movement resistance between P2 and the negative electrode of Cell 1 (N1) was estimated as several hundred ohm. The extra positive electrode (P2) was charged gradually and P2 potential also shifted to high as a result of the simulation study. Reliability of reference electrodes also was studied with the EDLC twin cell with four-reference electrodes.
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