An Intrinsic Self-Charging Biosupercapacitor Comprised of a High-Potential Bioanode and a Low-Potential Biocathode

An intrinsic self-charging biosupercapacitor built on a unique concept for the fabrication of biodevices based on redox polymers is presented. The biosupercapacitor consists of a high-potential redox polymer based bioanode and a low-potential redox polymer based biocathode in which the potentials of the electrodes in the discharged state show an apparent potential mismatch E_anode >E_cathode and prevent the use of the device as a conventional biofuel cell. Upon charging, the potentials of the electrodes are shifted to more positive (cathode) and more negative (anode) values because of a change in the a_ox -to-a_red ratio within the redox polymer matrix. Hence, a potential inversion occurs in the charged state (E_anode cathode ) and an open circuit voltage of >0.4 V is achieved and the biodevice acts as a true biosupercapacitor. The bioanode consists of a novel specifically designed high-potential Os complex modified polymer for the efficient immobilization and electrical wiring of glucose converting enzymes, such as glucose oxidase and flavin adenine dinucleotide (FAD)-dependent glucose dehydrogenase. The cathodic side is constructed from a low-potential Os complex modified polymer integrating the O₂ reducing enzyme, bilirubin oxidase. The large potential differences between the redox polymers and the prosthetic groups of the biocatalysts ensure fast and efficient charging of the biodevice.