We have already told you about lithium-sulfur batteries, or li-s, if you prefer. Many research institutes deal with them for their potential of being lighter and having more power density than lithium-ion batteries. The Alise Project has recently announced it has created a new prototype that is able to deliver 440 Wh/kg. Already pretty close to the production version goal of 500 Wh/kg.
Funded by the European Union, the Alise Project has the participation of 16 partners from 5 different countries. Williams Advanced Engineering and Seat are among them, but the company that will produce these batteries is probably Oxis Energy.