Energy Density and Fuels

In a standard alkaline battery, the important chemical reaction is 

The redox reaction in a battery has its own characteristic thermochemistry, just like the combustion reactions we have already looked at. The energy change of the chemical reaction fixes the voltage of an electrochemical cell. Some batteries, like the one that starts your car, are actually combinations of multiple cells, arranged so that the effective voltage of the battery is increased. 

Batteries are sometimes classified as either primary or secondary. A primary battery such as the typical alkaline cell becomes useless once the underlying 

Many new types of batteries have been introduced in recent years, as demand for portable electronic devices such as cell phones, music players, and laptop computers has soared. What factors influence the choice of battery types for a particular application One of the most important considerations is energy density, just as we discussed earlier for fuels. Table 9.5 summarizes typical characteristics and uses of several types of batteries. 

Ongoing battery research will continue to have major technologcal and economic impacts. 

---