YSZ Pellets for Solid Oxide Fuel Cells

Final Presentation

Presented by: Lazo TrkuljaAdvisor: Professor Elliott Slamovich

Graduate Student Advisor: Jeff Reding

Outline

• Overview of SOFC’s• Showing how research fits into big picture

• YSZ pellet processes• Ball milling, pressing, bisquing

• Obtaining Data for comparisons• Profilometer and peak edge removal

measurements

• Results and Conclusions

Solid Oxide Fuel Cells

• How do SOFC’s work?

)(2)(2

1 22 sOegO eOHgHsO 2)()( 22

2

Anode Reaction Cathode Reaction

Picture obtained from http://www.iit.edu/~smart/garrear/fuelcells.htm.

Goal

Electrolyte

Anode

rather than

YSZ Pellet Processing

• Combining components to form a slurry• YSZ powder, binder (Duramax HA-8), dispersant

(Duramax D-3005), DI water

• Ball Milling• Followed by drying of slurry in oven

• Pellet Pressing• Application of stearic acid to die• Approx. 68 MPa for approx. 1 min.

• Bisquing• Early stage of sintering

.

YSZ Pellet Processing

Profilometer

• Tencor Surface Profilometer

stylus

Profilometer

• Average Surface Roughness ( )

• Used to compare pellets

aR

1 2 3 ................ na

y y y yR

n

Roughness DataTotal Average Roughness for 2% Binder Composition

0

500

1000

1500

2000

2500

0 1 2 3 4 5

Pellet number

To

tal P

elle

t A

ve

rag

e R

ou

gh

ne

ss

(n

m)

Data

Total Average Roughness for 4% Binder Composition

0

500

1000

1500

2000

2500

0 1 2 3 4 5

Pellet number

To

tal P

elle

t A

ve

rag

e R

ou

gh

ne

ss

(n

m)

HistogramHistogram for Pellet #2 and 4% Binder

Set

0

1

2

3

4

5

6

100 500 900 1300 1700

Average Surface Roughness (nm)

Fre

qu

en

cy

DataTotal Average Roughness for the 10% Binder Set

0

500

1000

1500

2000

2500

3000

0 1 2 3 4 5

Pellet Number

To

tal A

ve

rag

e R

ou

gh

ne

ss

(n

m)

DataTotal Average Roughness for 2%, 4%, and 10% Binder

Sets

0

500

1000

1500

0 2 4 6 8 10 12

Binder Composition

Ro

ug

hn

ess

(n

m)

Edge Removal Data

• Measuring Edge Removals

Edge Removal Data

Total Average Edge Removal Peak for 2% and 4% Binder Sets

0

200

400

600

800

1000

1200

1400

0 1 2 3 4 5

Pellet Number

Ave

rag

e E

dg

e R

em

ova

l L

en

gth

(m

icro

ns)

2% Binder Set

4% Binder Set

Edge Removal DataTotal Number of Significant Edge Removals for 2% and 4% Binder

Sets

9

5

8

6

1920

19

10

0

5

10

15

20

25

1 2 3 4

Pellet Number

Nu

mb

er o

f E

dg

e R

emo

vals

2% Binder Set

4% Binder Set

Conclusions

• Definitive pellet set cannot be reached• Trade-off between 2% and 4% sets• User determines pellet priorities

• Pellet pressing is key in pellet quality• Uniform application of stearic acid on die• Careful handling of pellet after ejection

Acknowledgements

• Professor Elliot Slamovich

• Jeff Reding

• MSE faculty, staff, and students

Questions?

Trade-offFactor 2% Binder Set 4% Binder Set

Strength X

Lower Roughness

X X

Avg. Edge Removal Length

X

Lower Number of

Edge Removals

X