A hybrid bioelectrochemical device based on glucose/O2 enzymatic biofuel cell for energy conversion and storage

In this work, combining poly (methylene green)/glucose dehydrogenase (PMG/GDH) bioanode with Prussian blue/glucose oxidase (PB/GOD) biocathode, we developed a hybrid bioelectrochemical device based on glucose/O2 enzymatic biofuel cell (EBFC) to achieve energy conversion and storage. Depending on the reversible redox behaviors, PMG and PB play roles of dual-functional nanomaterials, not only as mediators to accelerate electrons transport between enzymes and electrodes surface, but also as pseudocapacitive materials to achieve energy storage. As a result, this hybrid device exhibited superior performance towards energy storage with a specific capacitance of 158.5 mF cm−2 at the current density of 1 mA cm−2. Meanwhile, a maximum output power density of 783.5 μW cm−2 in the pulse mode could be obtained, which had a prominent increment than that of the prototypical EBFC (87.5 μW cm−2) in the steady state. Furthermore, this hybrid device also exhibited better operational stability in long-term charge/discharge cycles test, at the current pulse of 1 mA cm−2. Through the combination of bioelectrocatalysis and capacitive energy storage, this developed hybrid device achieves effective energy conversion and storage, and provides a high output power to address the insufficient power supply of traditional EBFCs, which may enlarge the practical application of EBFCs in self-powered implantable and wearable devices.