TY - JOUR
T1 - Electrochemical behavior of amorphous MgNi as negative electrodes in rechargeable Ni-MH batteries
AU - Abe, Takayuki
AU - Tachikawa, Tomoyuki
AU - Hatano, Yuji
AU - Watanabe, Kuniaki
N1 - Funding Information:
This work was partially supported by a Grant-in-Aid for Scientific Research on Priority Areas A of New Protium Function of the Ministry of Education, Science, Sports and Culture of Japan. Thanks are offered to Japan Metals and Chemicals for the gift of the Mg 2 Ni powder. The authors wish to express their thanks to Professor I. Uchida (Tohoku University, Sendai, Japan) for fruitful discussions.
PY - 2002/1/17
Y1 - 2002/1/17
N2 - A cyclic voltammogram (CV) of amorphous MgNi clearly showing the hydrogen absorption-emission processes of amorphous MgNi was obtained by using a micropaste electrode technique. The hydrogen absorption was observed as an increase in the cathodic current below -0.9 V vs. Hg/HgO, and the emission as a broad anodic peak at ∼-0.9 V. These processes were considerably affected by immersion of the electrode in a KOH solution prior to measurements. The rising part of the cathodic current shifted to the cathodic direction depending on the immersion time. A decrease in the anode peak current and a remarkable shift of the anode peak potential were also observed. Using X-ray diffraction analyses, the deterioration of such electrode properties was attributed to formation of Mg(OH) 2 by the alkaline immersion. Potential step measurements gave an apparent diffusion constant (D app) of the hydrogen in the material of 6.8-9.4×10 -10 cm 2/s, irrespective of the immersion time. These results show that the Mg(OH) 2 formed has almost no effect on the diffusion of hydrogen but disturbs electron transfer processes on the electrode surface.
AB - A cyclic voltammogram (CV) of amorphous MgNi clearly showing the hydrogen absorption-emission processes of amorphous MgNi was obtained by using a micropaste electrode technique. The hydrogen absorption was observed as an increase in the cathodic current below -0.9 V vs. Hg/HgO, and the emission as a broad anodic peak at ∼-0.9 V. These processes were considerably affected by immersion of the electrode in a KOH solution prior to measurements. The rising part of the cathodic current shifted to the cathodic direction depending on the immersion time. A decrease in the anode peak current and a remarkable shift of the anode peak potential were also observed. Using X-ray diffraction analyses, the deterioration of such electrode properties was attributed to formation of Mg(OH) 2 by the alkaline immersion. Potential step measurements gave an apparent diffusion constant (D app) of the hydrogen in the material of 6.8-9.4×10 -10 cm 2/s, irrespective of the immersion time. These results show that the Mg(OH) 2 formed has almost no effect on the diffusion of hydrogen but disturbs electron transfer processes on the electrode surface.
KW - Amorphous MgNi
KW - Mg(OH)
KW - Micropaste electrode technique
KW - Rechargeable hydrogen batteries
UR - http://www.scopus.com/inward/record.url?scp=0037122547&partnerID=8YFLogxK
U2 - 10.1016/S0925-8388(01)01589-4
DO - 10.1016/S0925-8388(01)01589-4
M3 - 会議記事
AN - SCOPUS:0037122547
SN - 0925-8388
VL - 330-332
SP - 792
EP - 795
JO - Journal of Alloys and Compounds
JF - Journal of Alloys and Compounds
T2 - Proceedings of the International Symposium on Metal-Hydrogen (MH 2000)
Y2 - 1 October 2000 through 6 October 2000
ER -