Temperature Dependence of Iron and Cadmium Alkaline Electrodes

Abstract

The charge and discharge reactions of the alkaline iron and cadmium electrodes go over the soluble intermediates HFeO2-, FeO2-, and Cd (OH)42-, respectively. The saturation concentrations for these ionic species are rate determining as they directly influence the rates of diffusion and crystallization. B:~ calculating the temperature coefficients for the reactions involved, it is shown that the saturation concentrations for HFeOe-and FeO2-are highly temperature dependent while this is not the case for the cadmium intermediate. This explains the bad performance of the iron electrode at low temperatures. ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 141.210.2.78 Downloaded on 2015-06-06 to IP

Silicon and Iron as Resource-Efficient Anode Materials for Ambient-Temperature Metal-Air Batteries: A Review

“…Figure 24c shows the electrode structure of a sintered carbonyl iron electrode, which has recently been reported by Yang et al [100], indirectly pursuing the fundamental research by Öjefors et al [190,222,237,246]. At a first glance, the sintered iron electrode appears to be almost identical compared to the pressed-plate carbonyl iron electrode reported by Manohar et al However, the electrode was sintered for 15 min at 850 °C in argon atmosphere, which provides a higher mechanical stability of the anode given the interconnected electrode structure.…”

“…The most widely accepted mechanism was proposed by Kabanov et al in 1947 [234] and was, since then, reconsidered by many researchers such as Dražić et al [209,235,236]. According to the proposed mechanism, which is schematically depicted in Figure 23, the first oxidation reaction of iron in concentrated alkaline electrolyte involves four distinct reaction steps (I–IV) including the adsorption of two hydroxide anions on the iron electrode surface:I: Fe + OH − ⇌ FeOH ads + e − II: FeOH ads + OH − ⇌ Fe(OH) 2,ads + e − the dissolution of HFeO 2 − as an intermediate reaction product:III: Fe(OH) 2,ads + OH − ⇌ HFeO 2 − + H 2 O and the precipitation of Fe(OH) 2 on the iron electrode surface due to the limited solubility of HFeO 2 − in concentrated alkaline solution [237]:IV: HFeO 2 − + H 2 O ⇌ Fe(OH) 2 + OH − …”

Electricity generation and recovery of iron hydroxides using a single chamber fuel cell with iron anode and air-cathode for electrocoagulation

“…Furthermore, most authors [54][55][56][57][58][59][60][61][62] agree that the formation of Fe(OH) 2 is the first step in the formation of a passive layer and reaction (10) is the dominant reaction at pH values close to 9. The second oxidation step is shown in reactions (11) …”

Silicon and Iron as Resource-Efficient Anode Materials for Ambient-Temperature Metal-Air Batteries: A Review

“…Moreover, the underlying concept is also flexible in terms of electrode composition, which makes pressed-plate (carbonyl) iron electrodes very attractive for industrial energy storage applications [43]. Figure 24c shows the electrode structure of a sintered carbonyl iron electrode, which has recently been reported by Yang et al [100], indirectly pursuing the fundamental re-search by Öjefors et al [190,222,237,246]. At a first glance, the sintered iron electrode appears to be almost identical compared to the pressed-plate carbonyl iron electrode reported by Manohar et al However, the electrode was sintered for 15 min at 850°C in argon atmosphere, which provides a higher mechanical stability of the anode given the interconnected electrode structure.…”

“…III: Fe(OH)2,ads + OH -⇌ HFeO2 -+ H2O (20) and the precipitation of Fe(OH)2 on the iron electrode surface due to the limited solubility of HFeO2in concentrated alkaline solution [237]:…”