Glucose dehydrogenase and bilirubin oxidase were separately immobilised onto nanoporous gold electrodes. An Os redox polymer/PEDOT layer was deposited to prepare a biofuel cell/pseudocapacitor hybrid device. The device delivered 468 times higher power pulses than the biofuel cell alone. The hybrid device could operate for 50 charge/discharge cycles at 0.2 mA cm−2.