Electrokinetic energy conversion efficiency in nanofluidic channels.
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.
van der Heyden
Frank H J
FH
Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands.
Bonthuis
Douwe Jan
DJ
Stein
Derek
D
Meyer
Christine
C
Dekker
Cees
C
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