Mercedes-Benz's Vision EQXX traveled 1,000km on a single charge
mashable.com
mashable.com
For reference, compact EVs were getting 4 to 5 miles/kWh five+ years ago.
A Tesla model S gets about 3 miles/kWh, or a bit under half the efficiency of the EQXX.
Oh, and this discounts improvements in battery technology which would increase those effects.