Abstract
Water in its various forms has been found to be one of the most abundant sources of energy on the planet after solar energy, and hydroelectric power plays a key role in renewable-energy supplies. Traditionally, harvesting tremendous amounts of hydrodynamic energy requires the deployment of complex, bulky, and expensive electromagnetic generators, which become inefficient at lower volumes of flowing or falling water, and then the energy is stored when there is an excess, but these techniques remain largely unperfected. Regardless of the diversity of development strategies, adopted methodologies, and working mechanisms, there are a wide range of energy scavengers, to effectively harness environmental friendly alternative energy sources. Robust, sustainable and technologically effective water energy harvesting devices, especially hydroelectric nanogenerators, are in the research spotlight globally, due to their numerous benefits to society, including cost effectiveness, clean and continuous electricity generation, and environmental applicability. Here the design and working mechanism involved in the development of a microporous polymer membrane assisted unique hydroelectric generator (MPA-HEG) based on triboelectrification and electrostatic induction phenomena is reported, which scavenges energy from continuously dripping water droplets sliding onto the surface of a hydrophobic microporous polymer membrane. MPA-HEG utilizes a very simple architecture that consists of a hydrophobic microporous polymer, poly(tetrafluoroethylene) (PTFE), membrane on a single-sided copper-clad laminate as a substrate and an aluminium electrode. Unlike other reported water energy harvesting devices with similar functionalities, the rational design of MPA-HEG does not necessitate any technologically complex structures to be embedded in the substrate. It has also been revealed that the interaction of water droplets on the smooth, water-resistant solid polymer surface in MPA-HEG switches 'ON' and connects the originally disconnected equivalent electrical components at the solid-liquid-solid interfaces, giving an uninterrupted electrical circuit, and transmuting the conservative interfacial effects into a bulk mechanism. Consequently, the instantaneous power output shows a vast increase over equivalent devices that are constrained either to triboelectric interfacial effects or moisture-induced electricity generation. This could serve the purpose of validating the inherent advantages of developing self-powered electronic devices, and this approach can also be effectively exploited for boosted power generation with realistic future applications.