How does the battery in my smartphone work?

In this installment of Science from Scratch, Stephanie McClellan, MSc student in Science Communication explains the fundamentals of energy storage.

Battery technology can essentially be traced back to the discovery of ‘animal electricity’ by Alessandro Volta and Luigi Galvani in the eighteenth century. They created an electric circuit consisting of two different metals connected in series to a frog’s legs.

In contemporary terms, the frog’s legs acted as electrolytes – the source of the all important chemical reaction needed to produce the electrons to create a current. This possibly rather cruel experiment set the foundation for modern battery technology.

The most important development in battery technology in recent times has been the use of lithium ion (Li-ion) chemistry. Li-ion batteries are successful because of lithium’s physical properties. Being third on the periodic table, it has the lowest density, greatest energy to weight ratio, and the highest electrochemical potential of all metals.

This means that because lithium is highly reactive, it can store a lot of energy in its atomic bonds, giving Li-ion technology an advantage over traditional batteries. Li-ion batteries are therefore now commonly found in laptop computers, digital cameras, smartphones and even in some cars.

Manufacturers are continuing to improve battery technology, introducing new and enhanced chemical combinations to the market at a rapid pace. Large batteries could even be used in green communities to store energy from renewable generation, for later use when the wind isn’t blowing or the Sun isn’t shining.