A Parametric Study on Microfluidic Vanadium Fuel Cells

Author(s):  
Jin wook Lee ◽  
Deepak Krishnamurthy ◽  
Peter Hsiao ◽  
Erik Kjeang

A parametric variation of microfluidic vanadium fuel cells is studied. The present membraneless and catalyst-free fuel cell consists of a microfluidic channel network with two porous carbon paper electrodes. An aqueous vanadium redox pair as reactants is supplied to the porous electrodes in a flow-through configuration. The dimensions of porous carbon electrodes and microchannels are varied from the baseline design to investigate their impacts on the fuel cell performance. In addition, a dependency on the number of electrical contacts is examined. Numerical simulations are performed in parallel with experimental activities to understand the coupled effects of mass transport, electrochemistry, electron conduction, and fluid velocity field. The simulation results are compared with the measured data from each cell design for verification. An optimal cell design is discussed based on the current study and future research opportunities were proposed.

2013 ◽  
Vol 135 (2) ◽  
Author(s):  
D. Fuerth ◽  
A. Bazylak

In this work, an experimental microfluidic fuel cell is presented with a novel up-scaled porous electrode architecture that provides higher available surface area compared to conventional microfluidic fuel cells, providing the potential for higher overall power outputs. Our proof-of-concept architecture is an up-scaled flow-through fuel cell with more than nine times the active electrode surface area of the flow-through architecture first proposed by Kjeang et al. (2008, “A Microfluidic Fuel Cell With Flow-Through Porous Electrodes,” J. Am. Chem. Soc., 130, pp. 4000–4006). Formic acid and potassium permanganate were employed as the fuel and oxidant, respectively, both dissolved in a sulfuric acid electrolyte. Platinum black was employed as the catalyst for both anode and cathode, and the performances of carbon-based porous electrodes including cloth, fiber, and foam were compared to that of traditional Toray carbon paper (TGP-H-120). The effects of catalyst loading were investigated in a microfluidic fuel cell containing 80 pores per linear inch carbon foam electrodes. A discussion is also provided of current density normalization techniques via projected electrode surface area and electrode volume, the latter of which is a highly informative means for comparing flow-through architectures.


1996 ◽  
Vol 63 (1) ◽  
pp. 63-69 ◽  
Author(s):  
U.B. Holeschovsky ◽  
J.W. Tester ◽  
W.M. Deen
Keyword(s):  

2013 ◽  
Vol 534 ◽  
pp. 76-81 ◽  
Author(s):  
Enas Taha Kasem ◽  
Takuya Tsujiguchi ◽  
Nobuyoshi Nakagawa

Effect of modification of carbon paper with a thin layer of cobalt or gold on the performance of yeast-based microbial fuel cells was investigated. The modification was conducted by depositing Co or Au thin layer with different thickness, 5 nm and 30 nm, using a sputtering technique. The electrode performance was evaluated by measuring the electrode potentials and the fuel cell power output. The Co modification significantly increased the performance of the fuel cell, while the Au modification inhibited the performance. SEM observation indicated that the adhesion density of the yeast cells on the electrode surface was affected by the metals. It was confirmed that the electron transfer took place through the surface confined species at the mediatorless anode.


2008 ◽  
Vol 8 (8) ◽  
pp. 4132-4134 ◽  
Author(s):  
Tushar Sharma ◽  
A. Leela Mohana Reddy ◽  
T. S. Chandra ◽  
S. Ramaprabhu

Microbial Fuel Cells (MFC) are robust devices capable of taping biological energy, converting sugars into potential sources of energy. Persistent efforts are directed towards increasing power output. However, they have not been researched to the extent of making them competitive with chemical fuel cells. The power generated in a dual-chamber MFC using neutral red (NR) as the electron mediator has been previously shown to be 152.4 mW/m2 at 412.5 mA/m2 of current density. In the present work we show that Pt thin film coated carbon paper as electrodes increase the performance of a microbial fuel cell compared to conventionally employed electrodes. The results obtained using E. coli based microbial fuel cell with methylene blue and neutral red as the electron mediator, potassium ferricyanide in the cathode compartment were systematically studied and the results obtained with Pt thin film coated over carbon paper as electrodes were compared with that of graphite electrodes. Platinum coated carbon electrodes were found to be better over the previously used for microbial fuel cells and at the same time are cheaper than the preferred pure platinum electrodes.


2014 ◽  
Vol 64 (3) ◽  
pp. 881-895
Author(s):  
M. Rasmussen ◽  
R. D. Milton ◽  
D. P. Hickey ◽  
R. C. Reid ◽  
S. D. Minteer

Author(s):  
M. I. Rosli ◽  
M. Pourkashanian ◽  
D. B. Ingham ◽  
L. Ma ◽  
D. Borman ◽  
...  

This paper reviews some of the previous research works on direct visualisation inside PEM fuel cells via a transparent single cell for the water behaviour investigation. Several papers which have employed the method have been selected and summarised and a comparison between the design of the cell, materials, methods and visual results are presented. The important aspects, advantages of the method and a summary on the previous work are discussed. Some initial work on transparent PEM fuel cell design using a single serpentine flow-field pattern is described. The results show that the direct visualisation via transparent PEM fuel cells could be one potential technique for investigating the water behavior inside the channels and a very promising way forward to provide useful data for validation in PEM fuel cell modelling and simulation.


2021 ◽  
Vol 11 (4) ◽  
pp. 306-316
Author(s):  
Sanket Goel ◽  
Lanka Tata Rao ◽  
Prakash Rewatkar ◽  
Haroon Khan ◽  
Satish Kumar Dubey ◽  
...  

The development of microfluidic and nanofluidic devices is gaining remarkable attention due to the emphasis put on miniaturization of conventional energy conversion and storage processes. A microfluidic fuel cell can integrate flow of electrolytes, electrode-electrolyte interactions, and power generation in a microfluidic channel. Such microfluidic fuel cells can be categorized on the basis of electrolytes and catalysts used for power generation. In this work, for the first time, a single microfluidic fuel cell was harnessed by using different fuels like glucose, microbes and formic acid. Herein, multi-walled carbon nanotubes (MWCNT) acted as electrode material, and performance investigations were carried out separately on the same microfluidic device for three different types of fuel cells (formic acid, microbial and enzymatic). The fabricated miniaturized microfluidic device was successfully used to harvest energy in microwatts from formic acid, microbes and glucose, without any metallic catalyst. The developed microfluidic fuel cells can maintain stable open-circuit voltage, which can be used for energizing various low-power portable devices or applications.


Author(s):  
Pietro Asinari ◽  
Marco Coppo ◽  
Michael R. von Spakovsky ◽  
Bhavani V. Kasula

Throughout the last decade, a considerable amount of work has been carried out in order to obtain ever more refined models of proton exchange membrane (PEM) fuel cells. While many of the phenomena occurring in a fuel cell have been described with ever more complex models, the flow of gaseous mixtures in the porous electrodes has continued to be modeled with Darcy’s law in order to take into account interactions with the solid structure and with Fick’s law in order to take into account interactions among species. Both of these laws derive from the macroscopic continuum approach, which essentially consists of applying some sort of homogenization technique which properly averages the underlying microscopic phenomena for producing measurable quantities. Unfortunately, these quantities in the porous electrodes of fuel cells are sometimes measurable only in principle. For this reason, this type of approach introduces uncertain macroscopic parameters which can significantly affect the numerical results. This paper is part of an ongoing effort to address the problem following an alternative approach. The key idea is to numerically simulate the underlying microscopic phenomena in an effort to bring the mathematical description nearer to actual reality. In order to reach this goal, some recently developed mesoscopic tools appear to be very promising since the microscopic approach is in this particularly case partially included in the numerical method itself. In particular, the lattice Boltzmann models treat the problem by reproducing the collisions among particles of the same type, among particles belonging to different species, and finally among the species and the solid obstructions. Recently, a procedure based on a lattice Boltzmann model for calculating the hydraulic constant as a function of material structure and applied pressure gradient was defined and applied. This model has since been extended in order to include gaseous mixtures with different methods being considered in order to simulate the coupling strength among the species. The present paper reports the results of this extended model for PEM fuel cell applications and in particular for the analysis of the fluid flow of gaseous mixtures through porous electrodes. Because of the increasing computational needs due to both three–dimensional descriptions and multi-physics models, the need for large parallel computing is indicated and some features of this improvement are reported.


Author(s):  
Chen-Yu Chen ◽  
Yun-Che Wen ◽  
Wei-Hsiang Lai ◽  
Ming-Chang Chou ◽  
Biing-Jyh Weng ◽  
...  

One of the most difficult issues to fabricate a fuel cell with a complex design is the manufacturing method. To solve this difficulty, the authors applied an innovative method of fuel cell fabrication, i.e., rapid prototyping technology. The rapid prototyping technology can both fabricate the complex design and shorten the fabrication time. In this paper, the authors used a 3D software (CATIA) on the fuel cell design and utilized the rapid prototyping to accelerate the prototype development of complex stack designs and to verify the practicability of the new fabrication for fuel cells. The honeycomb shape methanol reservoir and cathode structure design of a direct methanol fuel cell (DMFC) and the complex flow distributor design of a monopolar air-breathing proton exchange membrane fuel cell (PEMFC) stack, which were almost impossibly manufactured by traditional manufacturing, were made in this study. The performance of the traditional air-pumping DMFC and that of an air-breathing DMFC were compared in this study. The feasibility of a complex pseudobipolar design DMFC stack was also verified. For the miniature air-breathing PEMFC made by rapid prototyping with ABS material, its performance is close to the state-of-the-art compared to previous published literatures (Hsieh et al. 2006, “Study of Operational Parameters on the Performance of Micro PEMFCs With Different Flow Fields,” Energy Convers. Manage., 47, pp. 1868–1878; Schmitz, A., Wagner, S., Hahn, R., Uzun, H., and Hebling, C., 2004, “Stability of Planar PEMFC in Printed Circuit Board Technology,” J. Power Sources, 127, pp. 197–205; Hottinen, T., Mikkola, M., and Lund, P., 2004, “Evaluation of Planar Free-Breathing Polymer Electrolyte Membrane Fuel Cell Design,” J. Power Sources, 129, pp. 68–72). A new solution to manufacture complex fuel cell design, rapid prototyping, has been first applied to the fabrication of complicated flow channels in ABS materials and directly used in both DMFC and PEMFC in this paper. Its feasibility was verified and its promising performance was also proved.


2015 ◽  
Vol 2015 ◽  
pp. 1-17 ◽  
Author(s):  
Chao Si ◽  
Xiao-Dong Wang ◽  
Wei-Mon Yan ◽  
Tian-Hu Wang

Water transport and the corresponding water management strategy in proton exchange membrane (PEM) fuel cells are quite critical for the improvement of the cell performance. Accuracy modeling of water transport in porous electrodes strongly depends on the appropriate constitutive relationship for capillary pressure which is referred to aspc-scorrelation, wherepcis the capillary pressure andsis the fraction of saturation in the pores. In the present PEM fuel cell two-phase models, the Leverett-Udellpc-scorrelation is widely utilized which is proposed based on fitting the experimental data for packed sands. However, the size and structure of pores for the commercial porous electrodes used in PEM fuel cells differ from those for the packed sands significantly. As a result, the Leverett-Udell correlation should be improper to characterize the two-phase transport in the porous electrodes. In the recent decade, many efforts were devoted to measuring the capillary pressure data and developing newpc-scorrelations. The objective of this review is to review the most significant developments in recent years concerning the capillary pressure measurements and the developedpc-scorrelations. It is expected that this review will be beneficial to develop the improved PEM fuel cell two-phase model.


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