In this week’s Economist magazine, a description of Lithium and Sodium ion batteries could easily have come straight from the GCSE Chemistry syllabus, particularly the atomic structure section.
The article describes the fact that with both metals being in Group 1 of the Periodic Table, they have a single electron in the outer shell, which is easily lost to form the positive ion. And this electron, rather than let us say being transferred to a chlorine atom to form sodium chloride, instead forms the electric current generated by the cell, which has a good “energy density”.
The context is that part of the push for transition from fossil fuels involves moving to electric vehicles (EV’s) which generally have a lithium ion battery. These typically use nickel and cobalt lithium oxides as the cathode, and lithium carbon (graphite) as the anode. (The reason that Lithium alone is not used is that as we know from our GCSE, Lithium is very reactive, too reactive in fact)
The problem with this design is that Lithium is scarce and like the Nickel and Cobalt requires mining which itself can damage the environment.
So the Economist argues that sodium ion cells, in alliance this time with iron and manganese, involve metals which in all cases are much more easily and abundantly available. But the magazine highlights the problem, again using the Chemistry syllabus, that because sodium is one further down in Group 1, it has more protons and hence is heavier and so may not be used in EV’s (already creaking under the weight of Lithium batteries) – but sodium ion batteries can however be used in heavy duty applications like power grid storage or even at home, when weight does not matter so much.
All of which goes to show just how important is the GCSE Chemistry syllabus!