Positive nickel-cadmium battery

The nickel-cadmium battery [6] has a positive electrode made of nickel hydrox-... 

The nickel-cadmium battery was invented by Jungner in 1899. The battery used nickel hydroxide for the positive electrode, cadmium hydroxide for the negative electrode, and an alkaline solution for the electrolyte. Jungner s nickel-cadmium battery has undergone various forms of the development using improved materials and manufacturing processes to achieve a superior level of performance. 

For many years, sintered-nickel electrodes have been used as the positive electrodes for sealed-type nickel-cadmium batteries. With an increase in the demand for high energy density, this type of elec-... 

Nickel-metal hydride batteries contain a nickel electrode similar to that used in nickel-cadmium batteries as the positive... 

For alkaline storage batteries requirements are often demanded exceeding by far those for lead storage batteries. The reason is that the suitable materials for the positive electrode are very expensive (silver oxide, nickel hydroxide) and thus the use of these storage batteries is only justified where requirements as to weight, number of cycles, or temperature range prohibit other solutions. Besides a few standardized versions — mainly for nickel-cadmium batteries — this has led to the existence of a large diversity of constructions for special applications [4-6, 108, 109],... 

Nickel(lll) oxide, prepared from a nickel(ii) salt and sodium hypochlorite, is used for the oxidation of alkanols in aqueous alkali [46]. Residual nickel(Ii) oxide can be re-activated by reaction with sodium hypochlorite. Nickel oxides have also long been used in the manufacture of the positive pole in the Edison nickel-iron rechargeable battery, now largely superseded by die lead-acid accumulator, and in the Jungner nickel-cadmium batteries used as button cells for calculators [47]. Here, prepared nickel oxide is pressed into a holding plate of perforated nickel. Such prepared plates of nickel(lli) oxide have been proposed as reagent for the oxidation, in alkaline solution, of secondary alcohols to ketones and primary alcohols to carboxylic acids [48]. Used plates can be regenerated by anodic oxidation. 

Rote et al. (1993, 1994) used a carotid thrombosis model in dogs. A calibrated electromagnetic flow meter was placed on each common carotid artery proximal to both the point of insertion of an intravascular electrode and a mechanical constrictor. The external constrictor was adjusted with a screw until the pulsatile flow pattern decreased by 25 % without altering the mean blood flow. Electrolytic injury to the intimal surface was accomplished with the use of an intravascular electrode composed of a Teflon-insulated silver-coated copper wire connected to the positive pole of a 9-V nickel-cadmium battery in series with a 250000 ohm variable resistor. The cathode was connected to a subcutaneous site. Injury was initiated in the right carotid artery by application of a 150 xA continuous pulse anodal direct current to the intimal surface of the vessel for a maximum duration of 3 h or for 30 min beyond the time of complete vessel occlusion as determined by the blood flow recording. Upon completion of the study on the right carotid, the procedure for induction of vessel wall injury was repeated on the left carotid artery after administration of the test drug. 

Nickel-cadmium batteries use a hydrate nickel oxide as positive electrode, a metallic cadmium as negative electrode and an aqueous solution of potassium hydroxide as electrolyte [17]. The production of electrons at the negative plate during discharge occurs via the following semi-reaction ... 

Ever since the nickel-cadmium battery came into existence, experts have been studying ways to recycle it. The first really widely-used batteries were of the open type. Their recovery at the end of their life was due to the ease with which they could be opened and the positive electrodes isolated so as to re-use the nickel. 

The negative electrodes in nickel-cadmium batteries are made up of finely distributed cadmium. The positive electrodes are composed of Ni(III) oxide hydroxide (with graphite or Ni powder added to enhance the conductivity). The electrolyte is usually a 20 % potassium hydroxide solution. 

Figure 10.14 The construction of a cylindrical nickel/ cadmium battery. Key A, seal By positive terminal C, cell lid D, connection to positive plate E, cell case Fy positive plate G, separator H, sintered metal foil Iy negative paste Jy connection to negative plate. Diagram supplied by Berec Ltd.

The procedure developed by Tanaka Chemical Co. is in the forefront of these methods. This company occupies almost a monopoly position as a supplier of cathode materials for the nickel-cadmium battery and the nickel-metal hydride battery. Metal hydroxides have been prepared via an amine complex. Spherical material is produced by adjusting the pH of the aqueous solution, the aging temperature, and the introduction rate of the reactant. This technology is applied to the cathode material of lithium-ion batteries and has been patented. Since precipitates with homogeneous distribution of various elements can be obtained using the co-precipitation technique. 

Another well-known shuttle is the nitrate shuttle in nickel/cadmium batteries caused by relics of nitrate (NO3) that have been left from the manufacturing process and are reduced to NH4 at the negative electrode and subsequently again oxidized to NO2 at the positive electrode, and so form a shuttle. 

Nickel/cadmium batteries (line 8 in Table 1.1) have been in technical use nearly as long as lead-acid batteries. They belong to a whole family of secondary batteries that are based on aqueous, but alkaline electrolyte, usually diluted potassium hydroxide. Nickel/cadmium, nickel/hydrogen, and nickel/metal hydride batteries are the most important members of this group. A further common feature of these battery systems is that they employ the nickel-hydroxide electrode as the positive one. Some of their basic features will be described in the following. 

The development of nickel/cadmium batteries started in the beginning of the twentieth century in parallel to that of the nickel/iron battery. The latter played an important role mainly as a sturdy traction battery that reached many charge/ discharge cycles. But after World War II it gradually lost its market, mainly because of the high hydrogen evolution rate and comparatively low power efficiency. The nickel/cadmium battery, however, still has a strong market position, mainly in its sealed version as a portable power source, but also as a flooded battery in traction and stationary applications. 

Figure 1.31 Equilibrium potentials of the negative and positive electrodes in a nickel/ cadmium battery, and current/voltage curves for O2 and H2 evolution and O2 reduction.

Nickel/hydrogen batteries are closely related to the nickel/cadmium battery, since they employ the same positive electrode and the same electrolyte. They have been developed for aerospace applications and are still the number one energy storage system in many satellite projects 60. 

The situation with respect to secondary reactions is shown in Fig. 1.34. It is similar to that in the nickel/cadmium battery shown in Fig. 1.32 as far as the positive electrode is concerned. Different is the situation at the negative electrode. The electrode potential is nearly the same, since the equilibrium potential of the hydrogen electrode is only about 20 mV below that of the cadmium electrode. But now hydrogen is used as active material instead of cadmium, and hydrogen evolution as well as hydrogen oxidation are fast reactions, since both are catalyzed by the platinum surface of the negative electrode. 

Lead-acid and nickel/cadmium batteries differ in plate design, as shown in Figure 7.4. In lead-acid batteries the type of the positive plate designates the cell type. The negative plate always is a grid plate. In traditional nickel/cadmium cells and batteries the positive and the negative plates are of the same construction. 

The positive and negative electrodes of pocket-plate nickel-cadmium batteries are made using the same basic design to hold the active materials. The pocket plates are buUt up of flat pockets of perforated steel strips holding the active materials. The thin steel strips are perforated by hardened steel needles or by a technique using profiled roller dies. The specific hole area is between 15 and 30%. The strips are nickel-plated to prevent iron poisoning of the positive active material. 

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