Tierr@_de_N@die: The future of the batteries stored energy it is called "solid state batteries". They will come with the promise of increasing the safety and reducing the costs. But we have still to wait for a while: this technology will not be in the market before 5 or 10 year. Meanwhile we will have to improve the regular ion-lithium batteries.
Lithium-ion batteries with their liquid electrolytes are able to store relatively high amounts of energy and are commonly used to power the tools of modern life, from cell phones to hearing aids. But the risk of fire and explosion has heightened interest in other types of batteries, and a solid-state sodium-ion battery offers the promise of increased safety at a lower cost.
Source (phys.org): Researchers report high performance solid-state sodium-ion battery