Bioinspired and Biodegradable Functionalized Graphene Oxide/Deacetylated Cellulose Acetate Composite Janus Membranes for Water Evaporation-Induced Electricity Generation

Harvesting electricity from natural water evaporation has recently become a popular research direction owing to its spontaneity, ubiquitousness, and sustainability. In this study, we demonstrate a bioinspired composite Janus membrane based on functionalized graphene oxide (FGO)/deacetylated cellulose acetate (dCA) nanofiber. FGO has a high surface charge and a low oxygen to carbon atom ratio (O AC /C AC ), which helps attract ions and facilitate the transfer of carriers. The hydrophilic dCA not only provides a driving force for water and ion transport in FGO but also accelerates water evaporation in the composite Janus membrane, thereby increasing the electrical output. As a result, a small piece of the membrane can provide ∼316 mV and ∼997 nA of voltage and current, respectively. The high electric energy output could be easily achieved through series and parallel expansion of the membrane and utilized to supply power to electronics or for capacitor charge. Once the generator has reached the end of its life cycle, dCA can be effortlessly biodegraded within a week without posing a threat to the environment. This work establishes a new paradigm for developing high-performance biodegradable electricity generators powered by water evaporation.