Ion-permselective conducting polymer-based electrokinetic generators with maximized utility of green water

Hydro-electric technology has gathered much attention by the virtue of water as the energy source. However, the low energy density of this technology severely limits its practical use. Here, we demonstrate a PEDOT:PSS-based transpiration-driven electrokinetic power generator (p-TEPG) that enables the utilization of a wider variety of real-world water resources for maximizing energy generation efficiencies. In addition to the conventional electrical double layer on the material surface, the p-TEPG builds an additional potential difference in the polymer matrix by the selective penetration of cations into the matrix that contains sulfonate functional groups. p-TEPG exhibits 80–250% higher energy density than carbon-based TEPG at the same resistance. Moreover, seawater produced enhanced volumetric energy/power densities (34.36 mJ cm⁻³ and 44.70 μW cm⁻³) and areal energy/power densities (410 μJ cm⁻² and 0.45 μW cm⁻²), respectively, compared to DI water on a single p-TEPG device, which is sufficient to charge electrical energy storage systems and directly operate low-powered electronic.