logo

SCIENCE CHINA Technological Sciences, Volume 62 , Issue 3 : 388-396(2019) https://doi.org/10.1007/s11431-018-9341-4

Effect of geometrical configurations on alkaline air-breathing membraneless microfluidic fuel cells with cylinder anodes

More info
  • ReceivedMay 21, 2018
  • AcceptedAug 26, 2018
  • PublishedDec 26, 2018

Abstract

Membraneless microfluidic fuel cells (MMFCs) outperform traditional membrane-based micro-fuel cells in membraneless architecture and high surface-to-volume ratio and facile integration, but still need substantial improvement in performance. The fundamental challenges are dictated by multiphysics regarding cell configurations: the interaction of fluid flow, mass transport and electrochemical reactions. We present a numerical research that investigates the effect of geometrical configurations (rod arrangement, cell length, rod diameter and spacer configuration) on the fuel transport and performance of an alkaline MMFC with cylinder anodes. Modeling results suggest that the staggered rod arrangement outperforms the in-line case by 10.1% at 50 μL min–1. Cell power output and power density vary nearly linearly with the cell length. In the case with 0.7 mm anodes and 0.3 mm spacers, the increased flow resistance at anode region drives the fuel to intrude into the spacer zone, leading to fuel transport limitation at downstream. The feasibility of non-spacer configuration is demonstrated, and the power density is 93.7% higher than the baseline due to reduced cell volume and enhanced fuel transport. In addition, horizontal extension of the anode array is found to be more favorable for scale-up, the maximum power density of 181.9 mW cm–3 is predicted. This study provides insight into the fundamental, and offers guidance to improve the cell design for promoting performance and facilitating system integration.


Funded by

the International Cooperation and Exchange of the National Natural Science Foundation of China(Grant,No.,51620105011)

National Natural Science Foundation of China(Grant,No.,51776026)

Innovation Support Foundation for Returned Overseas Scholars

Chongqing

China(Grant,No.,cx2017058)

Project(Grant,No.,2018CDXYDL0001)


Acknowledgment

This work was supported by the International Cooperation and Exchange of the National Natural Science Foundation of China (Grant No. 51620105011), the National Natural Science Foundation of China (Grant No. 51776026), the Innovation Support Foundation for Returned Overseas Scholars, Chongqing, China (Grant No. cx2017058), and the Fundamental Research Funds for the Central Universities (Grant No. 2018CDXYDL0001). Sui Pang-Chieh acknowledges the support from the Visiting Scholar Foundation of Key Lab of Low-grade Energy Utilization Technologies and Systems in Chongqing University (Grant No. LLEUTS-201504). Ned Djilali acknowledges the support in part from the Canada Research Chairs Program.


Supplement

Supporting Information

The supporting information is available online at tech.scichina.com and www.springerlink.com. The supporting materials are published as submitted, without typesetting or editing. The responsibility for scientific accuracy and content remains entirely with the authors.


References

[1] Wang Y, Leung D Y C, Xuan J, et al. A review on unitized regenerative fuel cell technologies, part B: Unitized regenerative alkaline fuel cell, solid oxide fuel cell, and microfluidic fuel cell. Renew Sustain Energy Rev, 2017, 75: 775-795 CrossRef Google Scholar

[2] Lee S H, Ahn Y. A laminar flow-based single stack of flow-over planar microfluidic fuel cells. J Power Sources, 2017, 351: 67-73 CrossRef ADS Google Scholar

[3] Escalona-Villalpando R A, Reid R C, Milton R D, et al. Improving the performance of lactate/oxygen biofuel cells using a microfluidic design. J Power Sources, 2017, 342: 546-552 CrossRef ADS Google Scholar

[4] Tanveer M, Kim K Y. Effects of geometric configuration of the channel and electrodes on the performance of a membraneless micro-fuel cell. Energy Convers Manage, 2017, 136: 372-381 CrossRef Google Scholar

[5] Galindo-de-la-Rosa J, Arjona N, Moreno-Zuria A, et al. Evaluation of single and stack membraneless enzymatic fuel cells based on ethanol in simulated body fluids. Biosens Bioelectron, 2017, 92: 117-124 CrossRef PubMed Google Scholar

[6] Martins C A, Ibrahim O A, Pei P, et al. Towards a fuel-flexible direct alcohol microfluidic fuel cell with flow-through porous electrodes: Assessment of methanol, ethylene glycol and glycerol fuels. Electrochim Acta, 2018, 271: 537-543 CrossRef Google Scholar

[7] Yoon S K, Fichtl G W, Kenis P J A. Active control of the depletion boundary layers in microfluidic electrochemical reactors. Lab Chip, 2006, 6: 1516 CrossRef PubMed Google Scholar

[8] Jayashree R S, Gancs L, Choban E R, et al. Air-breathing laminar flow-based microfluidic fuel cell. J Am Chem Soc, 2005, 127: 16758-16759 CrossRef PubMed Google Scholar

[9] Mousavi Shaegh S A, Nguyen N T, Chan S H, et al. Air-breathing membraneless laminar flow-based fuel cell with flow-through anode. Int J Hydrogen Energy, 2012, 37: 3466-3476 CrossRef Google Scholar

[10] Kjeang E, Michel R, Harrington D A, et al. A microfluidic fuel cell with flow-through porous electrodes. J Am Chem Soc, 2008, 130: 4000-4006 CrossRef PubMed Google Scholar

[11] Kjeang E, Michel R, Harrington D A, et al. An alkaline microfluidic fuel cell based on formate and hypochlorite bleach. Electrochim Acta, 2008, 54: 698-705 CrossRef Google Scholar

[12] Kjeang E, McKechnie J, Sinton D, et al. Planar and three-dimensional microfluidic fuel cell architectures based on graphite rod electrodes. J Power Sources, 2007, 168: 379-390 CrossRef ADS Google Scholar

[13] Zhang B, Ye D D, Li J, et al. Air-breathing microfluidic fuel cells with a cylinder anode operating in acidic and alkaline media. Electrochim Acta, 2015, 177: 264-269 CrossRef Google Scholar

[14] Arjona N, Goulet M A, Guerra-Balcazar M, et al. Direct formic acid microfluidic fuel cell with pd nanocubes supported on flow-through microporous electrodes. ECS Electrochem Lett, 2015, 4: F24-F28 CrossRef Google Scholar

[15] Zhang B, Ye D, Sui P C, et al. Computational modeling of air-breathing microfluidic fuel cells with flow-over and flow-through anodes. J Power Sources, 2014, 259: 15-24 CrossRef ADS Google Scholar

[16] Wang Y, Leung D Y C, Xuan J, et al. A vapor feed methanol microfluidic fuel cell with high fuel and energy efficiency. Appl Energy, 2015, 147: 456-465 CrossRef Google Scholar

[17] Gago A S, Morales-Acosta D, Arriaga L G, et al. Carbon supported ruthenium chalcogenide as cathode catalyst in a microfluidic formic acid fuel cell. J Power Sources, 2011, 196: 1324-1328 CrossRef ADS Google Scholar

[18] Morales-Acosta D, Ledesma-Garcia J, Godinez L A, et al. Development of Pd and Pd-Co catalysts supported on multi-walled carbon nanotubes for formic acid oxidation. J Power Sources, 2010, 195: 461-465 CrossRef ADS Google Scholar

[19] Zhang B, Ye D, Li J, et al. Electrodeposition of Pd catalyst layer on graphite rod electrodes for direct formic acid oxidation. J Power Sources, 2012, 214: 277-284 CrossRef ADS Google Scholar

[20] Jayashree R S, Egas D, Spendelow J S, et al. Air-breathing laminar flow-based direct methanol fuel cell with alkaline electrolyte. Electrochem Solid-State Lett, 2006, 9: A252 CrossRef Google Scholar

[21] Choban E R, Spendelow J S, Gancs L, et al. Membraneless laminar flow-based micro fuel cells operating in alkaline, acidic, and acidic/alkaline media. Electrochim Acta, 2005, 50: 5390-5398 CrossRef Google Scholar

[22] Hollinger A S, Maloney R J, Jayashree R S, et al. Nanoporous separator and low fuel concentration to minimize crossover in direct methanol laminar flow fuel cells. J Power Sources, 2010, 195: 3523-3528 CrossRef ADS Google Scholar

[23] Sun F, He H, Huo W. Polymer separator and low fuel concentration to minimize crossover in microfluidic direct methanol fuel cells. Int J Energy Res, 2015, 39: 643-647 CrossRef Google Scholar

[24] Huo W, Zhou Y, Zhang H, et al. Microfluidic direct methanol fuel cell with ladder-shaped microchannel for decreased methanol crossover. Int J Electrochem Sci, 2013, 8: 4827–4838. Google Scholar

[25] López-Montesinos P O, Yossakda N, Schmidt A, et al. Design, fabrication, and characterization of a planar, silicon-based, monolithically integrated micro laminar flow fuel cell with a bridge-shaped microchannel cross-section. J Power Sources, 2011, 196: 4638-4645 CrossRef ADS Google Scholar

[26] Whipple D T, Jayashree R S, Egas D, et al. Ruthenium cluster-like chalcogenide as a methanol tolerant cathode catalyst in air-breathing laminar flow fuel cells. Electrochim Acta, 2009, 54: 4384-4388 CrossRef Google Scholar

[27] Kjeang E, Brolo A G, Harrington D A, et al. Hydrogen peroxide as an oxidant for microfluidic fuel cells. J Electrochem Soc, 2007, 154: B1220 CrossRef Google Scholar

[28] Zhu X, Zhang B, Ye D D, et al. Air-breathing direct formic acid microfluidic fuel cell with an array of cylinder anodes. J Power Sources, 2014, 247: 346-353 CrossRef ADS Google Scholar

[29] Lee J W, Kjeang E. Chip-embedded thin film current collector for microfluidic fuel cells. Int J Hydrogen Energy, 2012, 37: 9359-9367 CrossRef Google Scholar

[30] Li L, Bei S, Xu Q, et al. Role of electrical resistance and geometry of porous electrodes in the performance of microfluidic fuel cells. Int J Energy Res, 2018, 42: 1277-1286 CrossRef Google Scholar

[31] Li L, Fan W, Xuan J, et al. Optimal design of current collectors for microfluidic fuel cell with flow-through porous electrodes: Model and experiment. Appl Energy, 2017, 206: 413-424 CrossRef Google Scholar

[32] Li L, Nikiforidis G, Leung M K H, et al. Vanadium microfluidic fuel cell with novel multi-layer flow-through porous electrodes: Model, simulations and experiments. Appl Energy, 2016, 177: 729-739 CrossRef Google Scholar

[33] Wang Y, Leung D Y C, Zhang H, et al. Numerical and experimental comparative study of microfluidic fuel cells with different flow configurations: Co-flow vs. counter-flow cell. Appl Energy, 2017, 203: 535-548 CrossRef Google Scholar

[34] Jayashree R S, Yoon S K, Brushett F R, et al. On the performance of membraneless laminar flow-based fuel cells. J Power Sources, 2010, 195: 3569-3578 CrossRef ADS Google Scholar

[35] Fuerth D, Bazylak A. Up-scaled microfluidic fuel cells with porous flow-through electrodes. J Fluids Eng, 2013, 135: 021102 CrossRef Google Scholar

[36] Yang Y, Ye D, Liao Q, et al. Enhanced biofilm distribution and cell performance of microfluidic microbial fuel cells with multiple anolyte inlets. Biosens Bioelectron, 2016, 79: 406-410 CrossRef PubMed Google Scholar

[37] Marschewski J, Ruch P, Ebejer N, et al. On the mass transfer performance enhancement of membraneless redox flow cells with mixing promoters. Int J Heat Mass Transfer, 2017, 106: 884-894 CrossRef Google Scholar

[38] Kwok Y H, Wang Y F, Tsang A C H, et al. Graphene-carbon nanotube composite aerogel with Ru@Pt nanoparticle as a porous electrode for direct methanol microfluidic fuel cell. Appl Energy, 2018, 217: 258-265 CrossRef Google Scholar

[39] Kwok Y H, Tsang A C H, Wang Y, et al. Ultra-fine Pt nanoparticles on graphene aerogel as a porous electrode with high stability for microfluidic methanol fuel cell. J Power Sources, 2017, 349: 75-83 CrossRef ADS Google Scholar

[40] Goulet M A, Ibrahim O A, Kim W H J, et al. Maximizing the power density of aqueous electrochemical flow cells with in operando deposition. J Power Sources, 2017, 339: 80-85 CrossRef ADS Google Scholar

[41] Li Y, He Y, Yang W. A high-performance direct formate-peroxide fuel cell with palladium-gold alloy coated foam electrodes. J Power Sources, 2015, 278: 569-573 CrossRef ADS Google Scholar

[42] Li Y, Feng Y, Sun X, et al. A sodium-ion-conducting direct formate fuel cell: Generating electricity and producing base. Angew Chem Int Ed, 2017, 56: 5734-5737 CrossRef PubMed Google Scholar

[43] Li Y, Sun X, Feng Y. Hydroxide self-feeding high-temperature alkaline direct formate fuel cells. ChemSusChem, 2017, 10: 2135-2139 CrossRef PubMed Google Scholar

[44] Ye D D, Zhang B, Zhu X, et al. Computational modeling of alkaline air-breathing microfluidic fuel cells with an array of cylinder anodes. J Power Sources, 2015, 288: 150-159 CrossRef ADS Google Scholar

[45] Zhang L, Li J, Zhu X, et al. Anodic current distribution in a liter-scale microbial fuel cell with electrode arrays. Chem Eng J, 2013, 223: 623-631 CrossRef Google Scholar

[46] Krishnamurthy D, Johansson E O, Lee J W, et al. Computational modeling of microfluidic fuel cells with flow-through porous electrodes. J Power Sources, 2011, 196: 10019-10031 CrossRef ADS Google Scholar

[47] Moore S, Sinton D, Erickson D. A plate-frame flow-through microfluidic fuel cell stack. J Power Sources, 2011, 196: 9481-9487 CrossRef ADS Google Scholar

[48] Salloum K S, Posner J D. A membraneless microfluidic fuel cell stack. J Power Sources, 2011, 196: 1229-1234 CrossRef ADS Google Scholar

[49] Wang H, Gu S, Leung D Y C, et al. Development and characteristics of a membraneless microfluidic fuel cell array. Electrochim Acta, 2014, 135: 467-477 CrossRef Google Scholar

[50] Ibrahim O A, Goulet M A, Kjeang E. Microfluidic electrochemical cell array in series: Effect of shunt current. J Electrochem Soc, 2015, 162: F639-F644 CrossRef Google Scholar

[51] Lu X, Wang Y, Leung D Y C, et al. A counter-flow-based dual-electrolyte protocol for multiple electrochemical applications. Appl Energy, 2018, 217: 241-248 CrossRef Google Scholar

  • Figure 1

    (Color online) Schematic illustration of the computational domain for baseline case (for interpretation of the references to color in this figure legend, the reader is referred to the web version of this article).

  • Figure 2

    (Color online) Validation of predicted (a) cell performance and (b) electrode potentials against experimental data.

  • Figure 3

    (Color online) Fuel concentration distribution in x-z cross sections at y = 5 (a) and 35 mm (b) for the staggered case, and at y = 5 (c) and 35 mm (d) for the in-line case. The flow rate is 200 μL min–1, and the cell voltage is 0.3 V. The anodes are labeled according to their relative positions.

  • Figure 4

    (Color online) Maximum power density for the staggered and in-line cases, respectively. The insert is the relative improvement.

  • Figure 5

    (Color online) Effect of cell length on (a) the maximum power output/density at 200 μL min–1, and (b) the corresponding anode current density distribution at the cell voltage of 0.3 V. Dashed lines are the averaged values for each case.

  • Figure 6

    (Color online) Effect of rod diameter on the (a) maximum power density at 200 μL min–1, and (b) anode current density distribution at 0.3 V.

  • Figure 7

    (Color online) (a) Velocity and (b) fuel concentration distribution of cells with 6, 3, and 0 spacers in x-z cross section at y = 20 mm. The flow rate is 200 μL min–1, and the cell voltage is 0.3 V.

  • Figure 8

    (Color online) Effect of spacer configuration on the performance output. The flow rate is kept at 200 μL min–1.

  • Figure 9

    (Color online) Predicted cell performance for vertical and horizontal arrangements.

  • Table 1   Geometrical parameters of the baseline case

    Parameter

    Value (mm)

    Main flow channel length (y) × height (z) × width (x)

    40.0 × 6.3 × 2.5

    Inlet channel length (x) ×height (z) × width (y)

    3.0 × 0.9 × 1.5

    Outlet channel length (x) ×height (z) × width (y)

    1.0 × 6.3 × 1.0

    Anode diameter

    0.526

    Spacer diameter

    0.5

    Centerline spacing betweenadjacent rods

    0.9

    Cathode catalyst layer thickness

    0.04

    Gas diffusion layer thickness

    0.28

  • Table 2   Nomenclature of terms in the governing equations

    Term

    Description

    a

    Density of catalytic active sites

    Cf

    Local fuel concentration

    Cf,ref

    Reference fuel concentration

    CO

    Local oxygen concentration

    CO,ref

    Reference oxygen concentration

    Df

    Fuel diffusivity

    DOeff

    Effective oxygen diffusivity

    F

    Faraday constant

    i0,f

    Exchange current density of formate oxidation reaction

    i0,O

    Exchange current density of oxygen reduction reaction

    M

    Molecular mass of oxygen

    n

    Transferred electrons per molecule

    nt

    Number of electrons transferred at the limiting step

    Ncrossover

    Fuel crossover flux at the cathode catalystlayer/main flow cannel interface

    p

    Pressure

    R

    Universal gas constant

    Sf

    Source term (only available on the anode surface)

    SO

    Source term (only available in the cathode catalyst layer)

    T

    Room temperature

    u

    Fluid velocity

    x

    Molar fraction of oxygen

    αa

    Anodic charge transfer coefficient

    αc

    Cathodic charge transfer coefficient

    β

    Reaction order

    ηa

    Anode overpotential

    ηc

    Cathode overpotential

    μ

    Viscosity

    ρ

    Fluid density

    ρg

    Gas mixture density

    σs

    Solid phase conductivity

    σe

    Electrolyte conductivity

    ϕe

    Electrolyte potential

    ϕs

    Electric potential

    ω

    Mass fraction of oxygen

Copyright 2020 Science China Press Co., Ltd. 《中国科学》杂志社有限责任公司 版权所有

京ICP备17057255号       京公网安备11010102003388号