It has been the bane of the electric vehicle revolution’s hopes—insufficient battery life. But now, Elon Musk has hinted that he might just have a solution to the thing that has dogged EVs for years. Elon Musk, a name that is synonymous with EV manufacturer Tesla, hinted on Monday that the company might just be able to mass-produce EV batteries that have 50% more energy density within three to four years. And although Musk’s track record for bold statements has been suspect, with some proclamations bearing fruit and others fizzling,…