Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9760332 | Journal of Power Sources | 2005 | 4 Pages |
Abstract
Crystalline α-Fe2O3 powder was prepared by the mechanical milling of crystalline α-FeOOH at room temperature in air. This result means that crystalline α-FeOOH is dehydrated by mechanical milling at room temperature. The obtained α-Fe2O3 powder worked as a rechargeable electrode material in lithium ion conductive organic electrolytes. The electrodes exhibited high discharge capacities of over 1000 mAh gâ1 corresponding to 6 Li per α-Fe2O3 at potentials ranging from the open circuit potential to 0.5 V (versus Li+/Li) in the first discharging (lithium insertion) process. This suggests that the valence deviation from Fe3+ in α-Fe2O3 to Fe0 may be caused by electrochemical reduction. In contrast, after the first discharge, the electrodes exhibited high charge capacities of more than 700 mAh gâ1 corresponding to 4.2 Li per α-Fe2O3 in the first charging (lithium extraction) process. The coulombic efficiency at the first cycle was about 70%, suggesting a valence deviation from Fe0 to Fe2+ or Fe3+ caused by electrochemical oxidation.
Related Topics
Physical Sciences and Engineering
Chemistry
Electrochemistry
Authors
Hideyuki Morimoto, Shin-ichi Tobishima, Yumiko Iizuka,