Donut Lab Claims 409 Wh/kg Battery Score, Yet Trust Remains Its Biggest Deficit

Donut Lab has put a hard number behind its battery pitch for the first time. An independent lab test, released by the company, recorded 409 Wh/kg alongside 805 Wh/L in energy density — figures that had gone unconfirmed despite months of outside questions.

The timing is awkward. Donut Lab had previously committed to having this so-called solid-state cell in production and powering a production EV before the end of Q1 2026. That deadline has come and gone without the vehicle or the manufacturing line materialising.

A single lab result does not repair a track record of missed commitments. For now, the 409 Wh/kg figure stands as a paper claim from a company whose credibility, as our colleagues at Electrek put it, is gone.