Influence of Preparation Condition of Iron Hydroxide/Nano-Carbon Composite on Its Properties

Abstract

The influence of the sol-gel preparation condition of the composites of iron hydroxide with fibrous nano-carbon on their electrode properties has been investigated. The morphology, namely particle dispersion feature, of the Fe(OH) x /nano-carbon composites and their electrode properties depend on the preparation conditions, such as titration rate and the kind of alkali. The specific capacity of the composite with carbon nanotube substrate is approximately twice by that with vapor-grown carbon fiber substrate, due to smaller size of the pitches within entangled tubes.

Effect of Cation Mixing on Utility of Iron in Iron/Carbon Nano-Fiber Composite Electrode

“…Iron/carbon nano-fiber composites have been prepared via solgel precipitation procedure reported previously: 14,15 ) to C (CNF) in all the cases was fixed to be 1 to 1 on the preparation, corresponding to Fe content of ca. 0.35-0.40.…”

“…[5][6][7][8][9][10][11][12][13][14][15] In the research groups where the author have belonged, iron-based composite electrodes have been investigated with nano-carbon materials as conductive agent. [9][10][11][12][13][14][15] They have succeeded to increase the utility of iron by compositing iron properly with nano-carbon conductive agents. In particular, nano-fibrous carbons are advantageous both to create large iron/ carbon/electrolyte ternary interface and to assure electronic conduction along fiber axis.…”

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

“…The sol-gel precipitation of iron hydroxide in alkaline solution has been reported previously. 20 In a typical case, 1 mol dm ¹3 KOH aq. was titrated into 100 cm 3 suspension of 1 mol dm ¹3 HCl containing 0.2 g of CNF and the prescribed amount of FeCl 3 .6H 2 O until the pH of the suspension became greater than 9.…”

“…The author has made some contribution by compositing iron species with fibrous carbons, which presents advantages such as a large surface area that allows good contact with iron, and sufficient conductivity along the fiber axis. 19,20 This study was undertaken with the aim of 'linking' the research history by varying the compositing conditions of iron species with a fibrous nano-carbon substrate. Here preparation methods of two kinds have been applied: sol-gel precipitation and ultrasonic mixing of nanoFe 3 O 4 .…”

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

“…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.…”