Honda Motor aims to double the driving range of its electric cars by the late 2020s when they start to adopt all-solid-state batteries, a new type of power source under development, the head of its research unit said on Wednesday.

The R&D center in Japan is meant to iron out Honda’s solid-state battery tech and for battery development, but series production is still a ways off.

Honda is readying its solid-state tech for mass production in the second half of the 2020s. The company’s CEO Toshihiro Mibe has eluded that solid-state batteries will also be the key to unlocking cheaper EVs.

Fresh off a successful launch of its Prologue electric SUV, Honda showcases its commitment to solid-state batteries, known as the ‘holy grail’ of EV batteries.

Solid-state battery tech could double the range of Honda’s EVs by the late 2020s, its R&D chief claims. Keiji Otsu said it wants to reduce the size of batteries by 50 percent and reduce cost by 25 percent.