Integrating reduced graphene oxides and PPy nanoparticles for enhanced electricity from water evaporation

Developing high-performance nanostructured materials is key to deliver the potential of hydrovoltaic technology into practical applications. As single-component materials have approached its limit in generating hydrovoltaic electricity, the development of multi-component hydrovoltaic materials has been necessary in continuously boosting the electricity output. Here, we report a hydrovoltaic material by integrating reduced graphene oxides and polypyrrole nanoparticles (rGO/PPy), where the rGO contributes improved conductivity and large specific surface area while PPy nanoparticles enable enhanced interaction with water. The device fabricated with this material generates a short-circuit current of 6 μA as well as a maximum power density of over 1 μW/cm³ from natural evaporation of water. And the substantial ion–PPy interaction enables robust voltage generation from evaporation of various salt solutions. Moreover, an outstanding scaling ability is demonstrated by connecting 10 devices in series that generate a sustainable voltage of up to ~2.5 V, sufficing to power many commercial devices, e.g. LED bulb and LCD screen.