Energy harvesting from water streaming at charged surface

Abstract

Water flowing at a charged surface may produce electricity, known as streaming current/potentials, which may be traced back to the 19th century. However, due to the low gained power and efficiencies, the energy conversion from streaming current was far from usable. The emergence of micro/nanofluidic technology and nanomaterials significantly increases the power (density) and energy conversion efficiency. In this review, we conclude the fundamentals and recent progress in electrical double layers at the charged surface. We estimate the generated power by hydrodynamic energy dissipation in multi‐scaling flows considering the viscous systems with slipping boundary and inertia systems. Then, we review the coupling of volume flow and current flow by the Onsager relation, as well as the figure of merits and efficiency. We summarize the state‐of‐the‐art of electrokinetic energy conversions, including critical performance metrics such as efficiencies, power densities, and generated voltages in various systems. We discuss the advantages and possible constraints by the figure of merits, including single‐phase flow and flying droplets.

All-atom molecular dynamics simulations of polymer and polyelectrolyte brushes

“…There have been a significant number of studies (including several by us) that have studied such nanofluidic electrokinetic energy generation and electroviscous effect. 160–164 In fact, through a series of recent continuum-calculation-based papers, we have explored the effect of functionalizing nanochannels with PE brushes in the electrokinetic energy generation in the presence of a background pressure-driven liquid flows. 35,154,165…”