Micro/nanofluidics-enabled energy conversion and its implemented devices

Abstract

Most people were not aware of the role of energy as a basic force that drives the development and economic growth of the world until the two great oil crises occurred. According to the conservation law, energy not only exists in various forms but is also capable of being converted from one form to another. The common forms of energy are mechanical energy, chemical energy, internal energy, electrical energy, atomic energy, and electromagnetic energy, among others. The fluids in nature serve as the most common carriers and media in the energy conversion process. Following the rapid development of microelectromechanical systems (MEMS) technology, the energy supply and conversion issue in micro/nano scale has also been introduced in research laboratories worldwide. With unremitting efforts, great quantities of micro/ nano scale energy devices have been investigated. Micro/ nanofluid shows distinct features in transporting and converting energy similar to their counterpart macroscale tasks. In this paper, a series of micro/nanofluid-enabled energy conversion devices is reviewed based on the transformation between different forms of energy. The evaluation and contradistinction of their performances are also examined. The role of micro/nanofluid as media in micro/nano energy devices is summarized. This contributes to the establishment of a comprehensive and systematic structure in the relationship between energy conversion and fluid in the micro/nano scale. Some fundamental and practical issues are outlined, and the prospects in this challenging area are explored.

Nanofluidic crystal: a facile, high-efficiency and high-power-density scaling up scheme for energy harvesting based on nanofluidic reverse electrodialysis

“…Alternative RED systems have also been explored for energy harvesting, among which nanofluidics has attracted great attention recently. Benefitting from the intrinsic property of ion-selectivity induced by the overlap of electrical double layers (EDLs) in nanostructures, nanofluidic channels function like ion exchange membranes [29][30][31]. Guo et al [32,33] explored this scheme by establishing an ionic concentration gradient across cation-selective nanochannels (or nanopores), so that more cations diffuse through the nanochannels than anions do, thereby forming an electrical current across the nanochannels, namely nanofluidic reverse electrodialysis (NRED).…”

Fabrication and Characterization of Thin Film Nickel Hydroxide Electrodes for Micropower Applications

“…Presently, there are several strategies for the miniaturization of electrical power sources. These include regenerative power technologies that generate power from microphotovoltaic arrays or thermoelectric, electrostatic, and piezoelectric devices. , In contrast, nonregenerative power supplies have a finite amount, or require a continuous supply of active materials/fuel for power generation, such as microfuel cells and microfluidic fuel cells . Other relevant electrochemical devices are microbatteries where the chemistries are in most cases indistinguishable from conventional batteries, though configurations, material deposition, postprocessing, and packaging methods applicable to macrobatteries are oftentimes not feasible below the centimeter scale.…”