title: Tailoring Membrane Nanostructure and Charge Density for High Electrokinetic Energy Conversion Efficiency.
abstract: The electrokinetic energy conversion (EKEC) of hydraulic work directly into electrical energy has been investigated in charged polymeric membranes with different pore charge densities and characteristic diameters of the nanoporous network. The membranes were synthesized from blends of nitrocellulose and sulfonated polystyrene (SPS) and were comprehensively characterized with respect to structure, composition, and transport properties. It is shown that the SPS can be used as a sacrificial pore generation medium to tune the pore size and membrane porosity, which in turn highly affects the transport properties of the membranes. Furthermore, it is shown that very high EKEC efficiencies (>35%) are encountered in a rather narrow window of the properties of the nanoporous membrane network, that is, with pore diameters of ca. 10 nm and pore charge densities of 4.6 × 10(2) to 1.5 × 10(3) mol SO3(-) m(-3) for dilute solutions (0.03 M LiCl). The high absolute value of the efficiency combined with the determination of the optimal membrane morphology makes membrane-based EKEC devices a step closer to practical applications and high-performance membrane design less empirical.
authors.affiliation: Department of Engineering, Aarhus University , Hangoevej 2, 8200 Aarhus N, Denmark.
authors.forename: Sofie
authors.initials: S
authors.lastname: Haldrup
authors.affiliation: Department of Engineering, Aarhus University , Hangoevej 2, 8200 Aarhus N, Denmark.
authors.forename: Jacopo
authors.initials: J
authors.lastname: Catalano
authors.affiliation: Department of Engineering, Aarhus University , Hangoevej 2, 8200 Aarhus N, Denmark.
authors.forename: Mogens
authors.initials: M
authors.lastname: Hinge
authors.affiliation: Interdisciplinary Nanoscience Center (iNANO) and Department of Chemistry, Aarhus University , Gustav Wieds Vej 14, 8000 Aarhus C, Denmark.
authors.forename: Grethe V
authors.initials: GV
authors.lastname: Jensen
authors.affiliation: Interdisciplinary Nanoscience Center (iNANO) and Department of Chemistry, Aarhus University , Gustav Wieds Vej 14, 8000 Aarhus C, Denmark.
authors.forename: Jan S
authors.initials: JS
authors.lastname: Pedersen
authors.affiliation: Department of Engineering, Aarhus University , Hangoevej 2, 8200 Aarhus N, Denmark.
authors.forename: Anders
authors.initials: A
authors.lastname: Bentien
keywords: electrokinetic energy conversion; membrane morphology; nitrocellulose; sulfonated polystyrene; transport properties