That needle coke – a hard, black, stony substance, which looks a lot like coal – is the main feedstock for the production of synthetic graphite, the chief ingredient in the anodes in lithium-ion batteries. Most of us now realise that the batteries inside our smartphones and electric cars are made of many obscure ingredients we dig out of the ground – more on this in Part Six – but few are aware that among those ingredients is a big dollop of crude oil.
