Laminated Cotton-Polyester-Based Microfluidic Fuel CellsFebruary 26, 2016Presented by : Catherine TangCalifornia State University, Los Angeles 1

What are Fuel Cells?Devices that convert chemical potential energy into electrical energy

• Characterized by type of electrolyte used

• Reactions at electrodes

• Electrolytes carry charged particles

• Catalysts speed reactions

• Electrical current directed out of fuel cell (FC)

K. Tran, T. Nguyen, A. Bartrom, A. Sadiki and J. Haan, "A Fuel-Flexible Alkaline Direct Liquid Fuel Cell", Fuel Cells, vol. 14, no. 6, pp. 834-841, 2014.

Alkaline direct liquid fuel cell.

exchanged across membrane. 2

Previous WorkY-shaped paper-based microfluidic fuel cells (MFCs)

But… they’re fragile.

Research Objective

Advantages: • Capillary action

means no need for external pump = inexpensive to make

• Easy to fabricate• Environmentally

friendly

Disadvantages:• Wet paper tears easily• 1.5 hours+ for optimal

values• 0.6-0.8 mA, rarely

1mA• 0.8-1 V

• Low current

Design a new platform to increase durability and current, and investigate the effects of:• Adding lamination• Changing material to cotton-polyester-based fabrics

3

Why Cotton and Polyester?Have the highest wicking

rates and is most commonly found

M. Reches, K. Mirica, R. Dasgupta, M. Dickey, M. Butte and G. Whitesides, "Thread as a Matrix for Biomedical Assays", ACS Appl. Mater. Interfaces, vol. 2, no. 6, pp. 1722-1728, 2010.

Why laminate?Lamination was shown

to increase fluid flow speed

laminated non-laminated 4

• Two-strip stacked design. Each strip carries its own anolyte and catholyte streams.

• Plastic wrap barrier• Thermally laminated at

120°C with laminating sheets

New Platform Design

Front, side, and back views

Active area

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Materials Tested:100% Cotton:• Shoelace• Flannel• CanvasCotton-Poly Blend:• 60-40 cotton-poly knit• 65-35 cotton-poly

shoelace

Experiment DetailsAnodeFuel: 5M HCOOHCatalyst: Pd/C

CathodeFuel: 30% H2O2Catalyst: Active Carbon

Current CollectorsSilver epoxy & steel meshAnode Reaction (Oxidation)

Cathode Reaction (Reduction)

T. Copenhaver, K. Purohit, K. Domalaon, P. Linda, B. Burgess, N. Manorothkul, V. Galvan, S. Sotez, F. Gomez and J. Haan, "A microfluidic direct formate fuel cell on paper", Electrophoresis, vol. 36, no. 16, pp. 1825–1829, 2015.

(Left) 60C-40P Knit. (Middle, Top to Bottom) 100C Canvas,

65C-45P Shoelace, 100C Shoelace. (Right) 100C Flannel6

0 1 2 3 4 5 6 7 8 9 100

0.2

0.4

0.6

0.8

1

1.2

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

100% Cotton(CD 3.1.2) canvas (PD 3.1.2) canvas (CD 4.4) flannel (PD 4.4) flannel (CD 1.3.3) shoelace(PD 1.3.3) shoelace

Current Density (mA/cm2)Po

tenti

al (V

)

Pow

er D

ensit

y (m

W/c

m2)

shoelace

• Highest CD and PD shoelaces

• Highest potential flannel

• High SD due to amount of fuel at inlets, and fuel crossover

100% Cotton

Current Density

(mA/cm2)Power Density

(mW/cm2)Potentia

l (V)

shoelace

AVG 9.43 1.35 0.62SD 1.96 0.44 0.15

flannelAVG 4.68 0.99 0.98SD 3.13 0.55 0.09

canvasAVG 0.11 0.02 0.63SD 0.14 0.03 0.43

Results 100% Cotton

flannelcanvas

*Graph is from one test and was selected based on how best it reflected average values. For illustration purposes only

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ApplicationsTwo in Series

Two 100% cotton shoelace FCs producing 1.9V at 1mA powers:

• 1 red LED• 1 yellow LED• Handheld

calculator

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ApplicationsFour in

Series

Four 100% cotton shoelace FCs producing 3.2 V at 0.9 mA powers:

• 1 red, yellow, blue, pink, green, and white LED individually 9

0 5 10 15 20 250

0.2

0.4

0.6

0.8

1

1.2

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

Cotton Polyester Blends(CD 3.3) shoelace (CD 3.1) knit (PD 3.3) shoelace (PD 3.1) knit

Current Density (mA/cm2)Po

entia

l (V)

Pow

er D

ensit

y (m

W/c

m2)•Highest CD and PD

shoelaces• Highest potential

shoelaces• High SD due to amount of fuel at inlets, and fuel crossover

Cotton-Poly

BlendsCurrent Density

(mA/cm2)Power

Density (mW/cm2)

Potential (V)

knitAVG 5.45 1.24 0.95SD 1.95 0.34 0.04

shoelace

AVG 15.18 2.75 0.67SD 8.50 2.00 0.25

shoelace

knit

Results Cotton-Polyester

Blends

*Graph is from one test and was selected based on how best it reflected average values. For illustration purposes only

10

0 5 10 15 20 250

0.2

0.4

0.6

0.8

1

1.2

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

100C and Cotton-Poly Blend(CD 3.1.2) 100C canvas (PD 3.1.2) 100C canvas (CD 4.4) 100C flannel (CD 1.3.3) 100C shoelace(CD 3.3) 65C-35P shoelace (CD 3.1) 60C-40P knit (PD 4.4) 100C flannel (PD 1.3.3) 100C shoelace(PD 3.3) 65C-35P shoelace (PD 3.1) 60C-40P knit

Current Density (mA/cm2)

Poen

tial (

V)

Pow

er D

ensit

y (m

W/c

m2)

ResultsOverall

100C shoelace

• Highest CD 65C-35P shoelace at 15.18 mA/cm2

• Highest PD 65C-35P shoelace at 2.75 mW/cm2

• Highest potential 100C flannel at 0.98 V*Graph is from one test and was

selected based on how best it reflected average values. For illustration purposes only

65C-35P shoelace

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Conclusion

> Additional tests needs to be performed with more materials. For future work, other barriers, the material’s weaving and thickness, the FC’s size and active area size will need to be further investigated to optimize this FC.

• No FC’s were torn• Material’s thickness and weave are also important parameters – shoelace type works best• Introduction of lamination + new materials found cotton-poly shoelace to be better than paper FC

Max PD (mW/cm2)

Max CD(mA/cm2)

Y-shaped paper FC 2.53 11.5065C-35P shoelace 2.75 15.18

+8.7% +32.0%

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Acknowledgements Dr. Gomez & the Fuel Cell Group & all my lab

colleaguesThank you for your kind support

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