Zinc/air cells

Other alkaline primary cells couple zinc with oxides of mercury or silver and some even use atmospheric oxygen (zinc—air cell). Frequendy, zinc powder is used in the fabrication of batteries because of its high surface area. Secondary (rechargeable) cells with zinc anodes under development are the alkaline zinc—nickel oxide and zinc—chlorine (see Batteries). 

The capacity of single-use alkaline zinc-air cells is twice that of manganese dioxide-zinc cells. They cost less than silver oxide-Zn batteries or Li batteries. The best example of consumer usage is the hearing-aid button cell. In sealed condition it can be... 

Iliev I., Kaisheva A., Stoynov Z. Pauling H.J, Mechanically rechargeable Zinc-air cells, Proceedings of the 3th International Battery Recycling Congress, July 2 - 4, 1997, Noordwijk Aan Zee, the Netherlands. 

A series of primary zinc-air cells are developed with capacity ranging from 100 Ah to 3300 Ah and nominal currents ranging from 2 A to 50 A. Technologies for the production of the air electrodes, porous zinc electrodes and for the assembling of the cells are elaborated. Some of the developed zinc-air cells are in production since 1981. 

The high capacity, low power zinc-air cells from the types ZV500 and ZV3000 are used as a power supply of navigation buoys in Baltic see for more than 10 years. Batteries from these cells operate for more than 1 year continuously. Zinc-air cells from the same types are successfully used in Bulgarian Himalayan expeditions (Lhotze 1981, Everest 1984 and Anapuma 1986) as power supply of the telecommunication system and electric light at the base camp. It must be underlined that in these cases the zinc-air cells... 

Active carbon promoted with small amount of silver is used as catalyst in the air electrodes of these cells. In Figure 15 we presented the discharge curve of the zinc-air cell ZV3000 at constant current 1 A. 

Figure 15. Typical discharge curve of a zinc-air cell ZV3000.

High power primary zinc-air cells are also developed with nominal current 20A -v 40A and capacity in the range 100 Ah -v 320 Ah. Typical application of these powerful zinc-air cells is as easy activated reserve power supply. These cells also can be successfully used for traction. 

Figure 16. Polarization curves of a zinc-air cell ZV320 at temperatures 20 °C and -20 °C Zinc-air cells from the types ZV280, ZV300, ZV320 and others are constructed and tested.

Figure 17. Voltage and power of a 12 cell battery, consisting of zinc-air cells ZV300 as a function of the current.

In Fig. 17 we have presented the current-voltage and the power characteristics of 12-cells battery from the cells type ZV300. It must be reminded that, when the zinc anode in the primary zinc-air cells is discharged, the cell is out of operation. By this, the air electrodes, which in principle can operate for a long time, are lost. In order to avoid this inconvenience, mechanically rechargeable zinc-air cells were developed [14]. The essential feature of the mechanically rechargeable zinc-air cell is that the air electrodes are used many times. 

Once the mechanically rechargeable zinc-air cell is discharged, the spend (oxidized) zinc electrode is removed from the cell together with the electrolyte and new zinc electrode and fresh electrolyte are introduced by which the cell is operational again. 

Several types of mechanically rechargeable zinc-air cells are developed in this laboratory, operating at nominal current 20A + 40 A with capacity ca.300 Ah. 

Table 1. Data for some zinc-air cells developed in CLEPS.

A variety of primary zinc-air cell and batteries are designed with capacity ranging from 100 Ah to 3300 Ah, operating at nominal currents from 2 to 40A at temperatures in the range +40 -t- -40°C. Mechanically rechargeable zinc-air cell are also developed and tested in experimental electric cars and scooters. 

Electrochemists have also learned how to make electrochemical cells in which one of the reactants is continuously supplied from outside the cell rather than contained within. One example is the zinc-air cell in which particles of zinc... 

Dewi et al. used a cationic polysulfonium membrane as a separator in a zinc—air cell. They showed that the polysulfonium membranes were highly effective in preventing zinc cation permeation from the anode to the cathode compared to the commercially available PP separators. 

The primary zinc—air cells have captured the hearing aid market, but the rechargeable zinc—air battery is still in the developmental stage. 

Earlier, such catalyst was used for the preparation of a 100 W rechargeable bipolar zinc-oxygen battery [328]. Also, nanostructured Mn02 combined with mesocarbon microbeads was prepared and used [329] in such batteries as a catalyst for oxygen reduction, which has a very good electrocatalytic activity with respect to oxygen, and in comparison with electrolytic Mn02. Prepared with this material, the all solid-state zinc-air cell... 

Rinaldi, Engineering Evaluation on Non-Reserve Zinc-Air Cells , ECOM 3528 (1972) 14) C.A. Nordell, Limiting Factors for Zinc-Air Batteries at Low and Elevated Temperatures , ECOM 3553 (1972) 15) J.W. Mellor, In-... 

A number of commercial zinc-air cells are available in reserve form usually they require simply the addition of clean fresh or sea water to activate them. 

Fig. 3.31 Continuous discharge curve through 2 Cl load of a 750 Ah zinc-air cell. Such cells have a 5A intermittent pulse capability and good capacity retention. (By courtesy of SAFT (UK) Ltd.)...

Zinc-air cells with electrolytes based on NH4C1 and having a similar OCV are also manufactured ... 

Iron-Air Cells. The iron-air system is a potentially low cost, high energy system being considered mainly for mobile applications. The iron electrode, similar to that employed in the nickel-iron cell, exhibits long life and therefore this system could he moie cost effective than die zinc-air cell. 

The cathode of the zinc-air cell uses a zinc metal anode and an air electrode similar to that for an alkaline fuel cell. The cell reaction is given in Equation 10.4. The cell is constructed with a pull-off... 

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