An innovative powerful and mediatorless H2/O2 biofuel cell based on an outstanding bioanode

► Mediatorless H2/O2 biofuel cell based on O2-tolerant hydrogenase and bilirubin oxidase. ► Covalent enzyme immobilization on carbon nanotubes ► Hydrogenase characteristics at high potential determine the cell performance. ► Delivering of 300 μW cm− 2 power density at 0.6 V with an OCV of 1.1 V