Batteries under development

This section will briefly describe the principles and problems of these new systems under development in the USA and elsewhere. Because of the early stage in their development, many of the problems lie in the compatibility of the materials of construction. There are often quite different approaches to finding a solution and to the design of the battery. 

The sodium/sulphur system is being discussed for load levelling and car traction and is believed to be close to commercial production in the UK as a traction battery for commercial vehicles. The overall cell reaction is usually written 

The major problems with the cell are associated with safety, since if in any 

The current collector is graphite felt which takes up all the volume inside the tube and there is also a central graphite rod which connects to the cell terminal. The negative current collector is the case and the molten sodium is stored below the cell and is only wicked up into the gap between the tube and the case as the sodium 

The second molten salt battery to have received detailed attention is the lithium/ iron sulphide battery. During discharge, the negative electrode reaction is the dissolution of Hthium from a lithium/aluminium alloy (10—20% Li), while the positive electrode reaction is the reduction of iron disulphide which occurs in stages 

The former gives a higher cell voltage but produces technological problems corrosion of the current collector by iron disulphide always occurs unless it is made 

Reaction (11.17) is not totally reversible and after the first discharge the positive electrode reaction is better represented by  

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Redox flow batteries, under development since the early 1970s, are stUl of interest primarily for utility load leveling applications (77). Such a battery is shown schematically in Figure 5. Unlike other batteries, the active materials are not contained within the battery itself but are stored in separate tanks. The reactants each flow into a half-ceU separated one from the other by a selective membrane. An oxidation and reduction electrochemical reaction occurs in each half-ceU to generate current. Examples of this technology include the iron—chromium, Fe—Cr, battery (79) and the vanadium redox cell (80). 

Specific energy vs specific power for several batteries under development, compared to the Pb- 43... 

As with the zinc systems, there are a number of lithium batteries under development, ranging in capacity from less than 5 mAh to 10,000 Ah, using various designs and chemistries, but having, in common, the use of lithium metal as the anode. 

Zinc-chlorine secondary batteries (under development)... 

Batteries under development for electric vehicle propulsion... 

The two types of lithium-air batteries under development, (a) aqueous electrolyte, protected anode design (b) non-aqueous electrolyte, unprotected lithium design. (Adapted from B. Scrosati, J. Hassoun and Y.-K. Sun, Lithium-ion batteries. A look into the future. Energy Environ. Sci. 4,2011,3287-3295. Reproduced by permission of The Royal Society of Chemistry.)... 

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