Battery start-ups are raising millions in the battle to crush Tesla

For powering your smartphone or your Tesla Model 3, there’s currently nothing better than the lithium-ion battery. Since its introduction in 1991, the rechargeable lithium battery has been the standard for everyday tech devices and electric-vehicle power. Many of the world’s more than 3 million electric vehicles run on lithium-ion batteries. But as the world races toward an electric future, it needs something better than the lithium-ion battery in order to keep pace.

“Lithium is pretty much hitting a wall right now. If you really want to increase energy density, you have to go to a completely different paradigm,” said Yifei Mo, a materials science and engineering professor at the University of Maryland. More energy density means cheaper, lighter batteries that last longer on a single charge.