Cell Batteries

Fig. 15. Relative discharge curves for (-) 2inc—silver oxide, and (—) 2inc—mercuric oxide batteries. Cells are of equal volume (21).

Figure 10. Charge-discharge cycle characteristics of an Ni-Cd battery (cell type 1200SC).

Charge-discharge capacity/mAh Figure 20. Charge-discharge characteristics of an Ni—MH battery (cell type AA). 

Figure 21. General charging characteristics of an Ni-MH battery (cell type 4/3A).

In an electrochemical cell, electrical work is obtained from an oxidation-reduction reaction. For example, consider the process that occurs during the discharge of the lead storage battery (cell). Figure 9.3 shows a schematic drawing of this cell. One of the electrodes (anode)q is Pb metal and the other (cathode) is Pb02 coated on a conducting metal (Pb is usually used). The two electrodes are immersed in an aqueous sulfuric acid solution. 

PSB electrolytes are brought close together in the battery cells where they are separated by a polymer membrane that only allows Na ions to go through, producing about 1.5 V across the membrane. Cells are electrically connected in series and parallel to obtain the desired voltage and current levels. The net efficiency of this battery working at room temperature is about 75%. It has been verified in the laboratory and demonstrated at multi-kW scale in the UK [92]. 

In the simple normal case a battery (cell) consists of two electrodes made of different materials immersed in an electrolyte. The electrodes are conducting metal... 

FIGURE 26.6 (a) p-doped conductive polymer in battery cell configuration (b) -doped... 

Those rare-earth AB -type hydrides were quickly utilized in rechargeable nickel metal hydride batteries where electrochemical hydrogen charging and discharging take place at ambient temperature. Such electrochemical hydrogen storage is reversible, when the negative hydride electrode (anode) is combined with the positive Ni electrode (cathode) in the battery cell.. 

Figure 7. Top panels Schematic diagram of 3-D cylindrical battery arrays in parallel row (left) and alternating anode/cathode (right) configurations. Middle panels Isopotential lines between cathode (C) and anode (A) for unit battery cells. Bottom panel Current densities (in arbitrary units, a.u.) at the electrode surfaces as a function of the angle 9 (see middle panel for definition of 9). The area of the cathodes and anodes is equal throughout the diagram. (Reprinted with permission from ref 19. Copyright 2003 Elsevier.)...

Silver is used as a catalyst to speed up chemical reactions, in water purification, and in special high-performance batteries (cells). Its high reflectivity makes it ideal as a reflective coating for mirrors. 

Cadmium(II) oxide Cd + O — CdO. This is used for cadmium plating baths, electrodes for batteries (cells), ceramic glazes, and insecticides. CdO is a deadly poison and carcinogen. 

Mercury batteries (cells) consist of a zinc anode and a mercuric oxide cathode. These cells produce a steady 1.3 volts throughout the cells hfetime. 

In an earlier report a worker exposed to an unknown concentration of thionyl chloride for approximately 6 minutes after a battery cell... 

The first true commercialization of a conductive polymer electrode in a battery cell has been carried out by Bridgestone/Sienko who market a... 

Recovery of metals such as copper, the operation of batteries (cells) in portable electronic equipment, the reprocessing of fission products in the nuclear power industry and a very wide range of gas-phase processes catalysed by condensed phase materials are applied chemical processes, other than PTC, in which chemical reactions are coupled to mass transport within phases, or across phase boundaries. Their mechanistic investigation requires special techniques, instrumentation and skills covered here in Chapter 5, but not usually encountered in undergraduate chemistry degrees. Electrochemistry generally involves reactions at phase boundaries, so there are connections here between Chapter 5 (Reaction kinetics in multiphase systems) and Chapter 6 (Electrochemical methods of investigating reaction mechanisms). 

Relationship between electrolytic cells and battery cells... 

Perhaps the best approach to understanding the operation of battery cells may be had by reconsidering a simple case of electrolysis. The non-spontaneous changes that occur during the electrolysis of an aqueous solution of zinc chloride may be represented by the following equations ... 

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. 

---