title: Electrokinetic energy conversion efficiency in nanofluidic channels.
abstract: We theoretically evaluate the prospect of using electrokinetic phenomena to convert hydrostatic energy to electrical power. An expression is derived for the energy conversion efficiency of a two-terminal fluidic device in terms of its linear electrokinetic response properties. For a slitlike nanochannel of constant surface charge density, we predict that the maximum energy conversion efficiency occurs at low salt concentrations. An analytic expression for the regime of strong double-layer overlap reveals that the efficiency depends only on the ratio of the channel height to the Gouy-Chapman length, and the product of the viscosity and the counterion mobility. We estimate that an electrokinetic energy conversion device could achieve a maximum efficiency of 12% for simple monovalent ions in aqueous solution.
authors.affiliation: Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands.
authors.forename: Frank H J
authors.initials: FH
authors.lastname: van der Heyden
authors.forename: Douwe Jan
authors.initials: DJ
authors.lastname: Bonthuis
authors.forename: Derek
authors.initials: D
authors.lastname: Stein
authors.forename: Christine
authors.initials: C
authors.lastname: Meyer
authors.forename: Cees
authors.initials: C
authors.lastname: Dekker
mesh_terms: D003198:Computer Simulation; D017076:Computer-Aided Design; D011211:Electric Power Supplies; D004560:Electricity; D004735:Energy Transfer; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007700:Kinetics; D044085:Microfluidics / Q000295:instrumentation* / Q000379:methods; D008962:Models, Theoretical; D036103:Nanotechnology / Q000295:instrumentation* / Q000379:methods; D014159:Transducers