All-solution-processed wearable moist-electric generators based on engineered nanocomposites of carbon nanotube and gelatin incorporated with PEDOT: PSS interfacial blocking layer

Abstract

Moist-electric generators (MEGs), capable of harvesting energy directly from ambient moisture, have been considered as promising and eco-friendly candidates for supplying continuous and stable electricity for self-powered electronics. Using a simple and practical all-solution process in ambient air, we developed wearable MEGs comprising engineered nanocomposites of multi-walled carbon nanotube and gelatin. A high open-circuit voltage of 0.95 V and short-circuit current (ISC) of 51.7 μA was achieved at a relative humidity of 90%. The operating mechanism of the proposed MEG was investigated by analyzing the protons generated by the dissociation of oxygen-containing functional groups during hydration. High sustainability and reliability of the electrical output performance for 100 h were demonstrated via charge screening induced by the interfacial blocking layer of poly(3,4-ethylenedioxythiophene):polystyrene sulfonate. Moreover, excellent mechanical stability of the wearable MEG was verified by analyzing the electrical output performance under a bending state and after 10,000 bending cycles with a strain of 60%. A practical self-powered application with wearability was demonstrated using MEGs in series at the cell level, which enabled the operation of light-emitting diodes by directly attaching to a commercial mask with a form-free surface.