Zinc-chlorine battery

The chlorine/zinc battery may also have potential in the near future. It has electrodes with pumped active material. 50 kWh prototypes have been built by Energy Development Associates, an American Gulf Western Company. 

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). 

While the zinc/chlorine battery is preferred for utility load-leveling applications [49], the zinc/bromine system is the more promising one for electric vehicle requirements [50, 51]. 

In the home lab, you can make hydrogen by adding strips of zinc from a flashlight battery to hydrochloric acid which consists of hydrogen (H) and another gas called chlorine (Cl). The zinc forms a compound (ZnCl2) with the chlorine and sets the hydrogen free (II ). 

Fig. 9.20 Comb-type bipolar electrodes for zinc-chlorine batteries (a) bipolar stack (b) unit cell...

Other flow batteries investigated for both electric vehicle applications and utility load leveling include zinc-chlorine. Zn-CL, and zinc-bromine, Zn-Br2, batteries. 

Although a battery cell depending on these reactions of zinc and chlorine could be used as a source of electrical energy, it is rather obvious that a battery involving the use of gaseous chlorine would hardly be practical in everyday use. Hence, before going any further into the problem of the general characteristics of battery cells, a battery more nearly suitable for actual use is considered. 

It is immediately apparent that the Daniell cell differs from the zinc-chlorine battery in that the electrode materials (i.e., zinc and copper) of the former are both metals that normally exhibit a tendency to lose electrons. If the Daniell cell is to function as a battery, both metals cannot lose electrons—one must lose and the other must gain electrons. In this particular case, the issue can be decided, qualitatively at least, in terms of the order of activity of the metals. From Table 11.1, it should be recalled that zinc is much more active chemically than copper hence zinc might be expected to lose electrons more readily than copper if the metals are in contact with solutions of their ions at the same concentration. It may be inferred correctly that the reactions that occur when the Daniell cell serves as a source of electrical energy are as follows ... 

Any consideration of the requirements to be fulfilled in the construction of battery cells should recognize first that the substances used as electrodes may be, but need not be, produced by electrolysis. In the earlier discussion of the zinc-chlorine battery, both of the substances involved at the two terminals were considered to be the products of a previously conducted electrolysis. However, the zinc-chlorine battery could just as well have been constructed by the use of zinc and chlorine produced by entirely nonelectrolytic methods. You should recall that, in connection with the description of the Daniell cell, no specifications were made with regard to the origin of any of the chemicals involved. This freedom to select suitable materials regardless of their origin or past history follows from the fact that the changes that occur during... 

Chlorine bleach is developed by Claude Louis BerthoUet in France Alessandro Volta makes a Copper/Zinc acid battery Humphry Davy invents a safety lamp that is used in coal mines without triggering an explosion... 

Use Manufacture of carbon tetrachloride, trichloroethylene, chlorinated hydrocarbons, polychloro-prene (neoprene), polyvinyl chloride, hydrogen chloride, ethylene dichloride, hypochlorous acid, metallic chlorides, chloracetic acid, chlorobenzene, chlorinated lime water purification, shrinkproofing wool, flame-retardant compounds, special batteries (with lithium or zinc) processing of meat, fish, vegetables, and fruit. For information, refer to the Chlorine Institute, 2001 L St., NW, Suite 506, Washington DC 20036. 

The reaction of zinc and chlorine has been used as the basis of a car battery. 

A possible destruction upon impact of zinc-halogen batteries might lead to the release of chlorine gas or bromine liquid and vapor. A study of the effects of spilling a full load of chlorine hydrate on hot concrete concluded that the probability of lethal accidents appears to be no more serious than that caused by gasoline fires in ICE-powered cars. The bromine vapor pressure above the organic complex is lower than that of chlorine above chlorine hydrate its lethal dose, however, is smaller and the spill cleanup and dispersion problems may be more severe. 

Zinc and chlorine were first suggested as battery materials some 150 years ago. Several efforts were made to build the battery the first realistic design based on the concept of using solid chlorine hydrate instead of gaseous or liquid chlorine had... 

The energy efficiency of the EV battery is <50%. The major cause of coulombic inefficiency (10-30%) is the chemical reaction of zinc with dissolved chlorine. Thanks to kinetic inhibitions, only about 1% inefficiency (over the complete cycle) derives from the evolution of hydrogen and carbon oxides. The latter derive from... 

The function of the separator in these batteries, similar to that of the water electrolyzer, is the separation of products (like hydrogen, chlorine, bromine, and zinc) which cause selfdischarge and efficiency loss when they diffuse across the separator. A non-ionic membrane can be used since the transport of the ionic species, like proton, chloride, bromide, and zinc ions, do not affect the cell efficiency. 

Engineering of the chlorine battery is well advanced but zinc/bromine cells exist only as small laboratory modules. 

---