A membraneless microfluidic fuel cell with continuous multistream flow through cotton threads

Abstract

Summary In typical membraneless microfluidic fuel cells, the anolyte and catholyte are driven by syringe pumps, increasing the overall size of the system and limiting its miniaturization. In this study, a membraneless microfluidic fuel cell with continuous multistream flow through cotton threads was proposed. Cotton threads are simply laid in parallel to form flow channels. Multistream flow through cotton threads is formed without any external pumps. Cell performances under various operation conditions are evaluated. The results show that the middle stream could separate other two streams effectively to prevent the diffusive mixing of anolyte and catholyte. A peak power density of 19.9 mW cm−2 and a limiting current density of 111.2 mA cm−2 are delivered. Moreover, the performance improves with the sodium formate concentration rising up to 2M, while it declines at 4M fuel concentration due to the weakened convection transport and product removal caused by the low flow rate. With increasing the flow rate, the performance is enhanced because of the improved fuel transport at the anode. The good performance as well as the constant‐voltage discharging curve indicates that the microfluidic fuel cell with cotton threads as flow channels provides a new direction for miniature power sources.

Advances in microfluidic electrochemical fuel cells in recent years

“…Rui Wu et al . reported a design of MFEFC with three inlets, and no external pump was needed to drive the electrolyte 86 . The electrolytes from the anode and the cathode were separated by the laminar effect in the microchannel, and mixing was prevented.…”

“…Rui Wu et al reported a design of MFEFC with three inlets, and no external pump was needed to drive the electrolyte. 86 The electrolytes from the anode and the cathode were separated by the laminar effect in the microchannel, and mixing was prevented. Cell performance could be intensified if flow rates enhanced and the voltage changed linearly, making the cell suitable for application in low-power electronics.…”

A membraneless microfluidic fuel cell with a hollow flow channel and porous flow‐through electrodes

“…Flowthrough porous electrodes have been investigated extensively for various flow configurations (ie, coflow, 28,45 counter flow, 35 radial flow, 39 orthogonal flow 49 ) with various electrode architectures 31 in a quest to manipulate the mixing and depletion regions with various fuel/oxidant combinations. 45,[49][50][51] This is the first effort of its kind to incorporate various cross-sectional structures including novel hollow-shaped central flow channel alongside flow-through porous electrodes to reduce the mixing region thickness, avoid fuel/oxidant crossover by using channel cross-section with narrow passage to isolate the depletion region from the mixing region, reduce the ohmic resistance in the electrolyte, and improve the ionic and reactant transportation across the channel. A numerical model was developed and validated with experimental data for flow-through porous electrodes.…”

Boost performance of porous electrode for microfluidic fuel cells: electrochemical modification or structure optimization?

“…The portable electronics with persistent rises of functionalities and performances have greater requirements for high-performance miniature power sources. [1][2][3][4] Therefore, increasing research interest is being devoted to the development of mobile power suppliers. 5 Among them, microfluidic fuel cells (MFCs) have attracted much attention as one intriguing power source for these types of applications.…”