Electrochemical characteristics of iron carbide as an active material in alkaline batteries

摘要

Electrochemical properties of iron carbide (Fe_3C) for use as an alkaline battery anode were investigated during charge-discharge cycles. Results of electrochemical measurements and Mossbauer spectroscopy suggested that Fe_3C is oxidized irreversibly to Fe_3O_4 during discharge processes and that the produced Fe_3O_4 is subsequently changed to Fe(OH)_2 and Fe during the charging process, raising the discharge/charge capacity in further galvanostatic cycles. In addition, the electrode particles were observed to be less than 100 nm in diameter and to be highly dispersed on the surface of carbon black. These phenomena seems to be caused by dissolution and deposition of Fe(OH)_2 and Fe via intermediate iron species, leading to exposure of a fresh Fe_3C surface to the electrolyte after the second discharge.