Electrochemistry of the Nickel Oxide Electrode: Part Iii. Anodic Polarization and Self-Discharge Behavior

Conway, B. E.; Bourgault, P. L.

doi:10.1139/v62-256

Cited by 79 publications

(39 citation statements)

References 5 publications

(6 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…22,23 In fact, the rate of oxygen evolution resulting from the self-discharge of the nickel electrode was observed to be depressed by adding heavy lanthanide oxides to the nickel active material, as shown in Fig. 9 amount at 3.5 wt %.…”

Section: Resultsmentioning

confidence: 95%

Effect of Lanthanide Oxide Additives on the High-Temperature Charge Acceptance Characteristics of Pasted Nickel Electrodes

Oshitani¹,

Watada²,

Shodai³

et al. 2001

J. Electrochem. Soc.

View full text Add to dashboard Cite

The development of electric and hybrid vehicles is proceeding against the backdrop of environmental problems, and high-output, high-energy-density nickel-metal hydride cells (NiMH cells) are finding application as the cardinal components for these vehicles. Because such uses require many NiMH cells to be connected in series and installed in small spaces inside vehicles, battery performance and service life are affected by how one controls the heat produced during the charging and discharging processes. This makes the cooling system an essential element, but the impossibility of completely preventing increases of battery temperature and evening out the temperature distribution among batteries has imposed the important technical task of raising the charge acceptance of batteries in the high-temperature range of 35-60ЊC. 1 However, the charge acceptance of NiMH cells declines considerably at high temperatures due to the small oxygen overpotential of the positive nickel electrodes. 2 The charging reaction of nickel electrodesis followed by the evolution reaction of oxygenbut at high temperatures the oxygen overpotential of the nickel electrode drops rapidly, and the charge acceptance decreases owing to conflict between the charging and the oxygen evolution reactions. For that reason one can find reports on various methods employed to increase the oxygen overpotential of nickel electrodes and improve charge acceptance. 2-6 These include the addition of cobalt in solid solution to nickel hydroxide, 3,6 which makes the oxidation potential of nickel electrodes decrease; the addition of compounds with group two elements, such as zinc oxide (ZnO), 4 cadmium oxide (CdO), 2 and calcium oxide (CaO), 4 or of rare earth compounds such as yttrium oxide (Y 2 O 3 ), 4 which act to raise the oxygen evolution potential; or the addition of NaOH or LiOH to the KOH electrolyte. 5 Especially effective is the addition of cobalt in solid solution to nickel hydroxide, but there is a limit to the amount added because it entails a drop in discharge potential. Therefore, actual batteries use these methods in combination, but it is still difficult to maintain a high charge acceptance at high temperatures above 50ЊC.Nevertheless, as noted previously, the oxygen evolution potential of nickel electrodes is suppressed by the addition of, for example, metal oxides whose metal ions have sp closed shells, but not much research has been focused on this mechanism or on the systematic relationship with the electron configurations of the metal ions making up those oxides. We therefore investigated oxides, and their combinations with lanthanide elements (Ln 3ϩ :[Xe] 4f n ), which are characterized by the progressive filling of the 4f orbitals from La 3ϩ to Lu 3ϩ and have sp closed shell-like ion structures,such as Zn 2ϩ , Ca 2ϩ , Cd 2ϩ , and Y 3ϩ , to determine their effects on the high-temperature characteristics of pasted nickel electrodes. ExperimentalNickel electrode preparation.-For the nickel hydroxide active material we used high-density spherical ...

show abstract

Section: Resultsmentioning

confidence: 95%

Effect of Lanthanide Oxide Additives on the High-Temperature Charge Acceptance Characteristics of Pasted Nickel Electrodes

Oshitani¹,

Watada²,

Shodai³

et al. 2001

J. Electrochem. Soc.

View full text Add to dashboard Cite

show abstract

“…Conway and Bourgault described the electrical behavior of the nickel electrode during open-circuit oxygen evolution as a large pseudocapacitance due to the discharge or desorption of oxygen containing radicals on its surface (20). The process is characterized as an electrochemical reaction rather than as a simple nonelectrochemical decomposition or desorption of a surface phase from the nickelic oxide.…”

Section: January 1965mentioning

confidence: 99%

The Forming Process in Nickel Positive Electrodes

Tuomi

1965

J. Electrochem. Soc.

103

View full text Add to dashboard Cite

A detailed study has been made of the phases produced and their geometric distribution during formation of Edison-type tubular positive nickel electrodes. The initial charging in lithiated KOH electrolytes converts the Ni(OH)~ to a beta phase having a solid solution range for di-and tetravalent nickel. The beta crystalline structure is related to LiNiO2. This phase can be further oxidized to alpha phase, a tetravalent nickelate having appreciable trivalent nickel solid solubility. Alpha phase is most readily formed during Ni (OH)2 oxidation in concentrated KOH or NaOH electrolytes, but does not form in LiOH electrolytes. The addition of LiOH to the battery electrolyte contributes to alpha phase discharge and limits alpha phase reformation. The contribution of alpha phase to electrochemical capacity is limited by a low effective exchange current as compared to the beta phase.

show abstract

“…Addition of heavy rare earth oxides to nickel electrodes has improved capacity-retention characteristics. We had expectations that this would mitigate the autolysis of nickel electrodes [6,7,12,13] and their reduction due to hydrogen evolved from MH electrodes, and this experiment showed that addition of rare earth oxides was effective for mitigating autolysis of the nickel electrode. On the contrary, there was no effect of adding rare earth oxides to MH electrodes on capacity retention.…”

Section: Effect On High-temperature Charge Efficiencymentioning

confidence: 99%