According to China's Xinhua news agency (via Gas2 and Clean Technica), Tesla could soon achieve this 500-mile battery thanks to a development in graphene-based anodes, which can reportedly quadruple the density and output of lithium-ion batteries.

Graphene, for those who don't know, is a carbon-based "super material" that's roughly 200 times stronger than steel but nearly transparent when laid out in sheets. First isolated in 2003, graphene is as an excellent conductor of heat and energy, and certainly an ideal material for batteries.