Asymmetric Charged Conductive Porous Films for Electricity Generation from Water Droplets via Capillary Infiltrating.

Hydrovoltaic devices are proposed as an alternative way to directly generate electricity due to the ubiquity of water and its interaction with specific porous structures. At present, the output power density of the reported device is limited by its low current density arising from the low surface charge density and inferior charge transport capability of the active materials. In this work, an asymmetric structure consisting of positively charged conductive polyaniline (PANI) and negatively charged Ti3C2TX MXene is proposed to build a hydrovoltaic device to achieve high conductivity and surface charge density simultaneously. An extra polyvinyl alcohol layer is utilized between PANI and MXene to reserve the asymmetric structure and maintain a constant voltage output. As a result, a peak current density of 1.8 mA/cm2 is achieved, which is 18 times higher than the previous peak current density of the device with an inert electrode. Our work of incorporating an asymmetric structure provides an alternative way to target high-efficiency hydrovoltaic devices with a large current density.