Formic acid microfluidic fuel cell evaluation in different oxidant conditions

Déctor, A.; Esquivel, Juan Pablo; González, M.; Guerra‒Balcázar, Minerva; Ledesma‐García, J.; Sabaté, N.; Arriaga, L.G.

doi:10.1016/j.electacta.2012.12.134

Cited by 48 publications

(33 citation statements)

References 28 publications

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“…Concerning these materials, it is interesting to note the sheer number of reactant combinations that have been attempted with CLFCs. Some of the liquid fuels used include dissolved hydrogen [45], methanol [46], [75], [78], [89], [126], [133], [134], formic acid [38], [54], [75], [79], [81], [123], [127], [129], [131], [135]- [139], hydrogen peroxide [48], [122], V 2+ [37], [55], [56], [58], [87], [92], [94], [96], [105], [106], glucose [80], [83]- [85], [111], [112], [130], glycerol [128], acetate [114], sodium borohydride [75], [91], hydrazine and ethanol [75]. Moreover, it would seem that many CLFC studies focus on other aspects such as catalysis which are not necessarily related to the co-laminar technology [78]- [81], [128], [137], [139].…”

Section: Research Perspectivesmentioning

confidence: 99%

Co-laminar flow cells for electrochemical energy conversion

Goulet

Kjeang

2014

Journal of Power Sources

104

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A recently developed class of electrochemical cell based on co-laminar flow of reactants through porous electrodes is investigated. New architectures are designed and assessed for fuel recirculation and rechargeable battery operation.Extensive characterization of cells is performed to determine most sources of voltage loss during operation. To this end, a specialized flow cell technique is developed to mitigate mass transport limitations and measure kinetic rates of reaction on flow-through porous electrodes. This technique is used in in conjunction with cyclic voltammetry and electrochemical impedance spectroscopy to evaluate different treatments for enhancing the rates of vanadium redox reactions on carbon paper electrodes. It is determined that surface area enhancements are the most effective way for increasing redox reaction rates and thus a novel in situ flowing deposition method is conceived to achieve this objective at minimal cost. It is demonstrated that flowing deposition of carbon nanotubes can increase the electrochemical surface area of carbon paper by over an order of magnitude. It is also demonstrated that flowing deposition can be achieved dynamically during cell operation, leading to considerably improved kinetics and mass transport properties. To take full advantage of this deposition method, the total ohmic resistance of the cell is considerably reduced through design optimization with reduced channel width, integration of current collectors and reduction of reactant concentration. With electrodes enhanced by dynamic flowing deposition the cell presented in this study demonstrates nearly a fourfold improvement in power density over the baseline design.Producing more than twice the power density of the leading co-laminar flow cell without the use of catalysts or elevated temperatures and pressures, this cell provides a lowcost standard for further research into system scale-up and implementation of co-laminar flow cell technology. More generally, the experimental technique and deposition method developed in this work are expected to find broader use in other fields of electrochemical energy conversion. am also very grateful to my graduate colleagues at SFU and friends in FCRel, with a special mention to Omar in particular, for all the pleasant conversations and good times.I wish there had been more.Last but not least, I'd like to acknowledge all the family and friends I was unable to spend quality time with due to this work. I look forward to seeing you all again.vi Tables Table 1. for their higher specific energy and energy density [6]. For the same reasons, the lower power (< 100 W) market which is driven by portable consumer electronics, is currently 2 dominated by closed cell lithium ion batteries in particular [7]. As these batteries reach their limits and fail to keep up with the energy requirements of modern electronics, micro fuel cells with passively pumped higher energy density liquid reactants such as methanol have been suggested as a potential replacement [8].Regardless...

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Section: Research Perspectivesmentioning

confidence: 99%

Co-laminar flow cells for electrochemical energy conversion

Goulet

Kjeang

2014

Journal of Power Sources

104

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“…The highly conductive gas diffusion electrode adsorbed oxygen from quiescent air and reduced the protons from the electrolyte‐saturated paper into water. The reactions at the respective electrodes and the overall reaction occurring in the fuel cell device are

true Anode : HCOOH \to CO_{2} + 2 H^{+} + 2 e^{-} E_{o} = - 0.22 V

true Cathode : 2 H^{+} + normalO_{2} + 2 e^{-} \to normalH_{2} normalO E_{o} = 1.229 V

true Overall : HCOOH + normalO_{2} \to CO_{2} + normalH_{2} normalO

…”

Section: Resultsmentioning

confidence: 99%

Selection of Graphite Pencil Grades for the Design of Suitable Electrodes for Stacking Multiple Single‐Inlet Paper‐Pencil Fuel Cells

et al. 2019

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We present a single-inlet paper-pencil based microfluidic fuel cell which works on the capillary driven fluid flow of a mixture of fuel (formic acid) and electrolyte (dilute sulfuric acid) solutions as a single entity. Different types of pencils are used to prepare the graphite electrodes to observe their effect on the fuel cell performance. The graphite electrodes are porous and act as a gas diffusion electrode which breaths in oxygen directly from the quiescent air and out CO 2 from the cell. The paper fuel cell also fabricated in different dimensions and connected as cell-stacks to enhance its performance. The paper-pencil device generates maximum open circuit potential of ∼ 2.5 V in series combination and maximum current density of ∼ 82 mA cm À 2 and power density of ∼ 100 mW cm À 2 in parallel combination. Later, rGOÀ Cu/CuO nanocomposite embedded electrodes are used to observe their effect on the device performance.[a] Dr.

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“…The OCV for this cell compares well with other cells using the same reactants. 8,19 It is difficult to distinguish the direct effect of surface area from the previous design, provided that the catalyst loading was different. However, the favorable synergetic effect of kinetics and local mass transport is observed by the increased voltage performance in the kinetic regime (at low current densities) as a result of increasing the flow rate.…”

Section: Resultsmentioning

confidence: 99%

Direct Formic Acid Microfluidic Fuel Cell with Pd Nanocubes Supported on Flow-Through Microporous Electrodes

Arjona

Goulet

Guerra‒Balcázar

et al. 2015

ECS Electrochemistry Letters

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A formic acid and dissolved oxygen microfluidic fuel cell demonstrated superior performance to air-breathing cells by a unique, hierarchical combination of optimized electrocatalyst particle geometry based on Pd nanocubes enclosed in {100} crystallographic planes and flow-through microporous electrodes with high surface area. The high performance is attributed to the favorable size and shape of the catalyst, the high surface-to-volume ratio, and the high localized mass transport rates inside the flow-through microporous electrodes. These results open up the opportunity to utilize oxygen as oxidant in miniaturized electrochemical cells without the constraints imposed by integration of air-breathing cathodes exposed to surrounding air. Microfluidic fuel cells (MFCs) are designed to eliminate the membrane used in conventional cells by employing microscale co-laminar flow at low Reynolds numbers.1-3 However, direct formic acid MFCs as well as other MFCs which use organic molecules as fuel and oxygen as oxidant usually show low performance due to a combination of voltage losses associated with electrochemical kinetics and mass transport to the active sites.2 Strategies for increasing cell performance generally address these two issues. In the first case, these cells are often limited by the availability of oxygen. Dissolved oxygen has low diffusivity (2 × 10 −5 cm 2 s −1 ) which limits the mass transfer and results in low cell performance. 4 The oxygen concentration in air is higher (10 mM) than in solution (2-4 mM) and the diffusivity is ten thousand times higher.2 Thus, some research groups have opted to fabricate air-breathing microfluidic fuel cells. 2,[5][6][7] Other groups have instead used high surface area materials such as multi-walled carbon nanotubes (MWCNTs) or three-dimensional electrodes to enhance the mass transfer in the anode and cathode streams. [8][9][10][11] In the latter case, researchers have attempted to improve the electrocatalytic properties of their electrode materials in regards to activity, stability, and/or selectivity. 12 The activity can be improved by means of decreasing the particle size, using particles with unique geometries which can be enclosed to the {111}, {100} or {110} crystallographic planes, and/or increasing the surface area. 13 The present work aims to create an optimized hierarchical electrode design specifically for liquid based microfluidic electrochemical cells, demonstrated here for a direct formic acid and dissolved oxygen fuel cell. We use small, customized Pd and Pt nanoparticles supported on three-dimensional microporous electrodes operated in flow-through mode. The proposed electrode is uniquely configured for optimum performance by a synergetic combination of four simultaneous strategies: i) catalyst particle size; ii) catalyst particle shape; iii) electrode active surface area; and iv) flow-through porous electrode matrix. ExperimentalThe synthesis of Pd nanocubes was performed using polyvinylpyrrolidone as a surfactant, ascorbic acid as a reducing * Electroche...

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Formic acid microfluidic fuel cell evaluation in different oxidant conditions

Cited by 48 publications

References 28 publications

Co-laminar flow cells for electrochemical energy conversion

Co-laminar flow cells for electrochemical energy conversion

Selection of Graphite Pencil Grades for the Design of Suitable Electrodes for Stacking Multiple Single‐Inlet Paper‐Pencil Fuel Cells

Direct Formic Acid Microfluidic Fuel Cell with Pd Nanocubes Supported on Flow-Through Microporous Electrodes

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