Is the ‘Holy Grail of batteries’ finally ready to bless us with its presence?

Donut Lab, a Finnish startup spun from Verge Motorcycles, claims to have solved solid-state battery technology with 400Wh/kg energy density and five-minute charging, supported by test reports from VTT Technical Research Centre of Finland. However, battery expert Eric Wachsman and others cite unsubstantiated claims and test failures—including vacuum seal loss during heat testing—and the company later admitted its flagship "100,000 cycles" specification is a design target, not verified.