Structural strategies to overcome limitations of solid-liquid charge separation, recombination, and transport for renewable electricity generation

Rain falls frequently across the surface of the earth, but the tremendous amount of rain energy is currently untapped. Solid-liquid charge separation for generating electricity via water flow across surfaces is highly ineffective due to severe fundamental issues, including critical limitations in charge separation, recombination, dissipation, and transport. Being an interfacial phenomenon, solid-liquid charge separation is fundamentally limited by the electric double layer and small nanoscale Debye length; hence, it is not considered viable for power generation. This study reports on a system that uses solid-liquid charge separation for generating electricity. Plug flow pattern through a millimeter-sized tube generates a large efficiency of 24.1% and continuous power density of 235 W m −2 . This large efficiency through a macroscale tube breaks the fundamental Debye length limit and is many orders of magnitude more than theoretically predicted. A trilayer FEP–Al–PVC tube provides charge stabilization, thus reducing charge recombination and dissipation. A fan-shaped multi-filament copper electrode overcomes charge transport limitations. An optimal guide support for flow pattern optimization increases charge separation. Therefore, structural guidance from materials addresses fundamental limitations. Plug flow effectively generates renewable electricity by harvesting energy of water from nature (e.g., rain or rivers), with clear advantages over other technologies. • A vertically oriented macroscale plug flow system that generates substantial power from rain energy by breaking the Debye length limit. • Efficiency defined as the electricity generated over the loss in potential energy through the tube surprisingly high at 24.1%. • Continuous power density of 235 W/m 2 , which is orders of magnitude larger than other technologies that harvest the energy of rain. • A practically viable and sustainable form of alternative energy for harvesting the energy of rain.