Zinc-halogen batteries

Despite the fact that the zinc/ ferricyanide system employs an alkaline electrolyte, the electrode reactions are quite similar to those in zinc/halogen batteries and battery constructions are usually bipolar too. 

Czerwihski and coworkers [345] reviewed the electrochemical applications of reticulated vitreous carbon (RVC). Special attention was paid to the use of RVC as an electrode support in zinc-manganese and zinc-halogen batteries. 

Amongst other new systems under study are the sodium/sulphur battery with sodium / -alumina solid electrolyte operating at 300-375°C and Li-FeS batteries operating at about 450°C. Long-term battery research is directed towards batteries that can operate at room temperature with aqueous electrolyte, such as zinc-halogen, aluminium-air, and iron-air. 

Except for zinc-halogen complex and metal-air systems, traction battery prototypes have been shown to operate at 60-75% efficiency (cf. Table 6). Higher values, usually quoted for high-... 

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. 

Health and Environmental Effects Document for Batteries the Lead/Acid and Zinc-Halogen Batteries, ANL/ES-129, Argonne National Laboratory to DOE, Contract No. W-31-109-Eng-38 (1982). 

The zinc halogen systems (both bromine and chlorine) were rediscovered during the last two decades and the efforts to commercialize these systems have been enormous. Madison Avenue orchestrated public relations hype certainly raised the awareness of the general public towards Zinc/Chlorine batteries but other than improved share prices there were no long term technological gains. 

The cathode must be an efficient oxidizing agent, be stable when in contact with the electrolyte, and have a useful working voltage. Oxygen can be used directly from ambient air being drawn into the cell, as in the zinc/air battery. However, most of the common cathode materials are metallic oxides. Other cathode materials, such as the halogens and the oxyhalides, sulfur and its oxides, are used for special battery systems. 

Zinc-halogen batteries, with the electrode reactions during discharge ... 

A classic example of a hybrid redox flow battery is the zinc-halogen system, such as zinc-bromine, which can be traced back to 1885 [103], and was systematically re-evaluated as a secondary battery in 1964 [104]. Similarly, zinc-chlorine was investigated in the late 1970s and 1980s but was found to be environmentally hazardous (chlorine gas formation) and more complicated in a system level than the zinc-bromine chemistiy. More recently, Lim et al. introduced a circulating aqueous electrolyte to the zinc-bromine battery (ZBB), which dramatically improved the performance of the system [105]. The electrode reactions of a ZBB are ... 

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