Paper-based lactate biofuel cell array with high power output

Printable wearable lactate biosensors have attracted significant attention, and printable lactate biofuel cells have gained popularity as suitable power supplies for these sensors. However, realizing an appropriate power supply for the practical application of these sensors as wearable devices, it is necessary to improve the output of lactate biofuel cells. In this study, we fabricated a lactate biofuel cell that employed paper substrate using screen printing. The proposed paper-based biofuel cell (PBFC) features a novel electrode design that affords an open circuit voltage of approximately 3.4 V when using an array with six cells in series. Furthermore, a 6 × 6 array of the lactate biofuel cell, i.e., an array comprising six cells in series and six cells in parallel, yielded a power output of 4.3 mW. To the best of our knowledge, this output of the proposed design is higher than those of previously reported lactate biofuel cells. Arrays of the proposed cell were capable of driving a Bluetooth low-energy device for wireless transmission, without requiring a booster circuit. A commercially available activity meter could be driven for 1.5 h using artificial sweat to fuel a 6 × 6 array of the PBFCs.