Toward Efficient Electrokinetic Energy Conversion with Topographic Modulation of Electrical Conduction

TL;DR

This paper explores how engineering surface topography in microchannels can enhance electrokinetic energy conversion efficiency by modulating electrical conduction and electric double layer interactions, supported by experimental and theoretical analysis.

Contribution

It introduces a novel approach of using nanoscale and microscale surface features to control electrical conduction and improve energy conversion in microfluidic systems.

Findings

Surface topography significantly affects electrical conductivity.

Engineered features enhance energy conversion efficiency.

Analytical models guide device design.

Abstract

This work presents experimental and theoretical analyses of electrokinetic flow in microchannels with glass and silica surfaces across a broad range of electrolyte concentrations (0.01 to 100 mM). We demonstrate simple but effective strategies for controlling electrical conduction by engineering nanoscale and microscale topographic features that directly modify the structure and extent of the electric double layer (EDL) and the interfacial ion conduction pathway. These tailored surface topographies modulate the overall electrical conductivity in slit microchannels through similar phenomena documented for nanochannels and nanopores due to the presence of liquid-filled nanoscale topographic features with high concentration of highly mobile protons. The findings of this work reveal that the interaction between tailored surface features and the EDL can substantially enhance energy conversion efficiency in microscale systems. These insights along with simple analytical models provide guidance for the rational design and optimization of scalable electrokinetic devices and are broadly relevant to numerous energy harvesting and charge-separation technologies.