Nickel battery electrodes

When nickel hydroxide is oxidized at the nickel electrode in alkaline storage batteries the black trivalent gelatinous nickel hydroxide oxide [12026-04-9], Ni(0H)0, is formed. In nickel battery technology, nickel hydroxide oxide is known as the nickel active mass (see Batteries, secondary cells). Nickel hydroxide nitrate [56171-41-6], Ni(0H)N02, and nickel chloride hydroxide [25965-88-2], NiCl(OH), are frequently mentioned as intermediates for the production of nickel powder in aqueous solution. The binding energies for these compounds have been studied (55). 

There are many methods of fabricating the electrodes for these cell systems. The eadiest commercially successhil developments used nickel hydroxide [12054-48-7] Ni(OH)2, positive electrodes. These electrodes are commonly called nickel electrodes, disregarding the actual chemical composition. Alkaline cells using the copper oxide—2inc couple preceeded nickel batteries but the CuO system never functioned well as a secondary battery. It was, however, commercially available for many years as a primary battery (see BatterieS-PRIMARY cells). 

This section gives a brief overview of the structure of nickel hydroxide battery electrodes and a more detailed review of the solid-state chemistry and electrochemistry of the electrode materials. Emphasis is on work done since 1989. 

In normal battery operation several electrochemical reactions occur on the nickel hydroxide electrode. These are the redox reactions of the active material, oxygen evolution, and in the case of nickel-hydrogen and nickel-metal hydride batteries, hydrogen oxidation. In addition there are parasitic reactions such as the corrosion of nickel current collector materials and the oxidation of organic materials from separators. The initial reaction in the corrosion process is the conversion of Ni to Ni(OH)2. 

The influence of zinc intercalation on processes in nickel oxide electrode and on the long life of Ni-Zn batteries was also studied. 

The nickel hydroxide electrode is used since decades in the mckel-iron(Edison)-or nickel-cadmium(Jungner)-storage battery Here the anodes consist mainly of nickel oxide powder pressed into a support and current feeder, whilst for electro-organic oxidations and electroanalytical measurements a thin nickel oxide hydroxide layer on a nickel support is used. 

Fig. 6.11 Six-cell nickel-meial hydride batiery. 1. positive cap, connected to the nickel oxide electrode 2, can, connected to metal hydride electrode and serving as negative terminal 3. separator 4. cathode 5, anode 6. plastic battery case which contains interconnected cells and electronic management system. (By permission of Duracell.)...

Nickel Hydroxide Electrodes, 1990. (Ed. D. Corrigan and A. Zimmerman.) Rechargeable Lithium Batteries, 1990. (Ed. S. Subbarao, V. Koch, B. Owens and W. Smyrle.)... 

Ultrasound has also been successfully employed in the preparation of other battery electrode materials. An example of this is the electrochemical impregnation of nickel hydroxide cathodes for batteries which was increased by 15% under ultrasonic irradiation. Active material content was 14.0 g/dm3 under ultrasonic irradiation, and 12.0 g/dm3 without. The active nickel hydroxide species formed by both electrochemical or chemical impregnation was not affected, but the deposition speed was higher and the grain size was smaller [133],... 

Nickel batteries use P-Ni(OH)2 as electrode material. This material converts to P-NiOOH during the charging process and this rearranges to y-NiOOH when it is overcharged. This last process is accompanied by a significant expansion, because of the difference in density between P-NiOOH and y-NiOOH, which may result in poor electric contact between the current collector and P-Ni(OH)2/p-NiOOH, with concomitant decrease in the discharge capacity of the battery. Among others, layered double hydroxides of Ni and other metals, often termed stabilized a-Ni(()H), or doped Ni(0H)2, have been tested as electrode materials (Bernard et al., 1996). The effect of the interlayer anions on the electrochemical performance of layered double hydroxide electrode materials has been recently studied by Lei et al. (2008) (see Chapter 6). 

Of course, one of the most common uses for nickel is coinmaking, specifically, the five-cent coin. The nickel coin is an alloy made of copper and nickel. Another important and common use for this metal is the nickel-cadmium battery, which contains a nickel-oxide electrode. This battery is rechargeable, making it ideal for calculators, computers, and other small electrical appliances. 

The redox reaction of nickel hydroxide and nickel oxide hydroxide, the electrochemi-cally active compounds at the positive electrode of a nickel battery, was investigated. The thermodynamics of non-ideal solid solutions were applied to the reversible potential as a function of the state-of-discharge. In a temperature range 5 to 55°C two parameter activity coefficient models perform significantly better than one parameter models. 

McBreen comprehensively reviewed nickel hydroxide battery electrodes, the solid state chemistry of nickel hydroxides, and the electrochemical reactions of the Ni(OH)21 NiOOH couple. Any critical discussion of the thermodynamic data of nickel oxide hydroxides with higher oxidation states has to refer to this splendidly written account of nickel solid state electrochemistry. 

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