Wearable high-powered biofuel cells using enzyme/carbon nanotube composite fibers on textile cloth

Wearable biofuel cells with flexible enzyme/carbon nanotube (CNT) fibers were designed on a cotton textile cloth by integrating two components: bioanode fibers for glucose oxidation and O₂-diffusion biocathode fibers for oxygen reduction. The anode and cathode fibers were prepared through modification with glucose dehydrogenase and bilirubin oxidase, respectively, on multi-walled carbon nanotube-coated carbon fibers. Both biofibers woven on the cloth generated a power density of 48 μW/cm² at 0.24 V from 0.1 mM glucose (human sweat amount), and of 216 μW/cm² at 0.36 V, when glucose was supplied from a hydrogel tank containing 200 mM glucose. Our fiber-based biofuel cell deformed to an S-shape without a significant loss in cell performance. Furthermore, we demonstrated a series-connection involving the tying of biofibers on a cloth with batik-based ionic isolation. The booster four cells generate power at 1.9 V that illuminated an LED on the cloth.