Factors Influencing Iron utilization of Iron Compound/Carbon Nanofiber Composite Electrode

Abstract

A comparative study of composite electrodes consisting of nanoparticles of iron compounds with fibrous nanocarbon in alkaline electrolyte was conducted to ascertain the morphological or composition factors that can increase the iron capacity. The preparation method and the iron content of a composite electrode affect the capacity per unit of iron mass. Particularly by increasing the iron content using a solution process, the capacity can be increased considerably up to ca. 460 mAh (g Fe) −1 for an Fe(OH) x /carbon composite. Such improved iron utilization in these composites suggests a catalytic effect of some intermediate species. Addition of a model candidate of an intermediate species, FeOOH, even of only 3 wt%, can improve the iron utilization in a Fe(OH) x /carbon composite.

Influence of Polymer Coating on the Electrode Properties of Fe₃O₄/Carbon Nano-fiber Composite in Alkaline Electrolyte

“…The gravimetric ratio of Fe 3 O 4 :CNF was fixed at 16:5 according to previous results. 16 These components were mixed in ethanol using ultrasonic irradiation. The Fe 3 O 4 /CNF mixture was collected by filtration.…”

“…14 Iron utilization has been improved up to 400 mAh per unit mass of iron: half of the theoretical capacity, by the optimum design of composite electrodes of nano-sized iron species loaded on a CNF surface, and the fabrication of such composites using sol-gel precipitation or ultrasonic-aided mixing of nano-sized magnetite (Fe 3 O 4 ) and CNF. 15,16 Such composites have rather high surface area, and thus hydrogen evolution by-reaction is unavoidable. Here the polymer coating of electrode materials has been proposed to inhibit hydrogen evolution.…”