BEIJING (Reuters) - Chinese electric vehicle maker GAC Aion's Hyper brand said on Friday it has finished R&D on all-solid-state batteries that will be first used in Hyper cars in 2026.

The 400 watt hour per kilogram solid-state batteries tout more than 1,000 kilometres (621 miles) of driving range.

Solid-state batteries enable improved safety, a longer lifespan and faster charging compared with conventional lithium-ion batteries that use flammable liquid electrolytes, but constraints in raw material availability, intricate manufacturing processes and resultant high costs are mass adoption roadblocks.