Power Generation by Reverse Electrodialysis in a Microfluidic Device with a Nafion Ion-Selective Membrane

Abstract

An energy conversion microchip consisting of two circular microchambers and a Nafion-filled microchannel is fabricated using standard micro-electro-mechanical systems (MEMS) techniques. When the chambers are filled with KCl solutions with different concentrations, the Nafion microchannel acts as a cation-selective membrane and results in the generation of electrical power through a reverse electrodialysis (RED) process. The current-potential characteristics of the Nafion membrane are investigated for devices with various microchannel lengths and electrolyte concentration ratios. It is shown that for a given voltage, the current and generated power increase with a reducing channel length due to a lower resistance. In addition, a maximum power density of 755 mW/m2 is obtained given an electrolyte concentration ratio of 2000:1 (unit is mM). The optimal device efficiency is found to be 36% given a channel length of 1 mm and a concentration ratio of 1000:1 (mM). Finally, no enhancement of the short circuit current is observed at higher concentration ratios.

Two-Dimensional Ti3C2Tx MXene Membranes as Nanofluidic Osmotic Power Generators

“…(c) Thermal dependence of osmotic current and cation transference number. (d) Power generation performance of MXene membranes (blue star) compared with state-of-the-art nanostructured osmotic power generators. ,,,,,,− The black solid line indicates a linear fit of micro- and nanoscale multiporous power generators, and red dashed lines represent a linear fit of single-pore systems with extremely small aperture area.…”

Fabrication of Polymer Microfluidics: An Overview

“…Microfluidics is the science and technology of systems that process or manipulate small amounts of fluids and particles in the channels with dimensions of tens to hundreds of micrometers [ 1 ]. With the ongoing extensive research and development of microfluidic platform technology, its potential applications have been constantly explored and demonstrated, ranging from chemical and biological detection and analysis [ 2 , 3 ], the synthesis and characterization of catalyst particles [ 4 ], point-of-care diagnoses [ 5 ], drug discovery and delivery systems, food safety inspection [ 6 ], environmental monitoring [ 7 , 8 ], life sciences [ 9 ], and energy generation [ 10 , 11 , 12 , 13 ]. Due to its small scale, microfluidics presents competitive advantages over conventional approaches, such as lower reagent consumption and waste, enhanced reaction efficiency, reduced analysis time, simplified procedures, and high portability [ 14 ].…”

Enhancing the efficiency of energy harvesting from salt gradient with ion-selective nanochannel

“…[5,9] Recently, nanofluidic channel systems have been proposed as new candidate to harness the osmotic energy owing to its high ionic throughput and excellent ion selectivity caused by surface charge effect. [10][11][12] Concerning the recent reports on nanofluidic/microfluidic RED, [13][14][15][16][17][18][19][20][21][22][23][24] the harvested power density up to 2.6 × 10 3 W m 2 ⁄ has been obtained by the generated electric power would decrease by reducing the channel length (L< 400nm). [26] According to our previous research, it was ascribed to the strong short channel effect, particularly at the low-concentration end, which eventually weakens the ion selectivity of the nanochannels.…”