"Vanadium was actually discovered twice, and one of the discoverers was the Swedish chemist Nils Sefstrom, who named it after the Norse goddess of beauty, Vanadis," says the Italian chemist, Prof Andrea Sella of University College London.
To explain why, Sella produces a flask of an easily misidentified yellow-coloured liquid.
It is, he says, a solution of "oxidised" vanadium in sulphuric acid - that is, vanadium that has been stripped of all five of its outermost electrons (it inhabits column five of the periodic table).
He then adds a shiny lump of a zinc-mercury amalgam and begins to shake the concoction violently.
"The zinc is going to allow us to put electrons back onto the vanadium - the chemical process we call 'reduction'," he explains.
The solution quickly turns green, and then gradually becomes blue. "And if we keep shaking for another few minutes, we will eventually end up with a violet colour."
Each change of colour represents one further electron being passed on to the vanadium.
"The ease with which you can hand electrons to the vanadium and take them away - this is the basis of a very, very stable battery."
Vanadium "redox flow" batteries are indeed stable. They can be discharged and recharged 20,000 times without much loss of performance, and are thought to last decades (they have not been around long enough for this to have been demonstrated in practice).