This document presents research on developing hybrid carbon-bismuth nanoparticle electrodes for energy storage applications. The researchers studied using bismuth as an electrocatalyst to improve the performance of vanadium redox flow batteries. Cyclic voltammetry tests showed that electrodes with bismuth and multiple layers had higher peak currents and better reversibility than carbon-only controls. Adding bismuth and more layers indicated improved electrochemical reaction reversibility. Future work could characterize the effect of carbon on stabilizing bismuth peaks and test scaled-up hybrid electrodes in actual vanadium redox flow batteries.

1. Hybrid Carbon-Bismuth
Nanoparticle Electrodes
for Energy Storage
Applications
Trevor Yates, Junior, University of Cincinnati
Adam McNeeley, Pre-Junior, University of Cincinnati
William Barrett, Sophomore, University of Cincinnati
GRA: Abhinandh Sankar
AC: Dr. Anastasios Angelopoulos
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2. Why is renewable energy important?
1. 86.4% of the world’s energy supply is based around fossil fuels
2. At least millions of years for dead organisms to decompose and transform
3. Energy demand doubles every 14 years
“By the year 2020, world energy consumption is projected to increase an
additional 207 quadrillion (2.07 x 1017) BTUs. If the global consumption of
renewable energy sources remains constant, the world’s available fossil fuel
reserves will be consumed within 104 years.”
- US Department of Energy, 2010
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3. PurposeCarbon-Bismuth
Studies
Vanadium Studies
Vanadium
Redox
Flow
Batteries
http://img.wallpaperstock.net:81
/windmills-
wallpapers_22092_1600x1200.j
pg
http://www.messib.eu/assets/im
ages/VRB_1_general_layout_V
RFB.jpg
3

4. http://www.
digsdigs.co
m/photos/fi
edler-
house-
christmas-
lights-1.jpg
4

5. Cost Analysis: 1 KW Unit
Vanadium 1.5 M VOSO4 and 10 M H2SO4 electrolyte costs
$1.60/kg
Storage Tanks 153 Liters of electrolyte required to generate 1 kW
Pumps 0.0866 L/min flow required with 0.5 m head
pressure
Electrodes Volume based on required current and current
density
Membrane Same SA as electrode and Nafion 117 costs
$100/ft2
Total: $64 (153 L electrolyte) + $500 (4 x 50 L Tanks) + $110 (1 hp pump)
+ $40 (2 electrodes) + $2,634 (26.34 ft2 membrane) = $3,348
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6. Introduction
 Basic Electrochemistry
 Vanadium Redox Flow Batteries
 Cyclic Voltammetry
 Application Methods
 Research Parameters
 Results and Interpretations
 Future Studies
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7. Electrochemistry
 The study of the flow of electrons in
chemical reactions
 Redox Reactions
 Anode and Cathode
 Reaction Potentials
7

8. http://www.messib.eu/assets
/images/VRB_1_general_lay
out_VRFB.jpg
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9. Cyclic Voltammetry
 Voltage Sweep
 Between two set values
 Current Peaks
 Scan Rates
 Determined by user
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10. Layer by Layer
Standard Directed
Bismuth
Tin (Sn)
Polymer
Carbon
Polymer
Bismuth
Tin (Sn)
Carbon
Polymer
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11. What we Have Learned...
 Polymer important for LbL
 NaOH wash helpful
 Particles deteriorate
 Glovebox
 Carbon Stabilizes Bismuth
 sLbL is better than dLbL 4Bi + 3O2 2Bi2O3
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12. Carbon
No
Carbon
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13. sLbL
dLbL
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14. Vanadium Studies
Negative electrode
V3+/V2+
Reduction reaction happens near H+
reduction
Electrocatalyst
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15. Bismuth as an Electrocatalyst
Makes it easier for electrochemical
reaction to happen
Terms of Cyclic Voltammetry
Shifts peak currents closer together
Increases peak current heights
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16. -1 -0.8 -0.6 -0.4 -0.2
-8
-6
-4
-2
0
2
4
Potential (V vs Ag/AgCl)
CurrentDensity(mA/cm
2
)
Bismuth Improves Performance of Negative Electrode
8-Layers/Carbon
4-Layers/Carbon-Bismuth
8-Layers/Carbon-Bismuth
4/Carbon-Bismuth
8/Carbon-Bismuth
8/Carbon
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17. Ipc and Ipa
Ipc
Cathodic peak current
Bottom peak
Ipa
Anodic peak current
Top peak
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18. How to Calculate Ipc and Ipa
Have to extrapolate line
Finding a “baseline”
Why?
Glassy Carbon produces current
This is considered zero
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19. -1.4 -1.2 -1 -0.8 -0.6 -0.4 -0.2 0
-0.01
-0.005
0
0.005
0.01
40mV/s 8 Layer Carbon Control sLbL (Example)
CurrentDensity(mA/cm
2
)
Potential (V vs. Ag/AgCl)
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20. Ipc and Ipa Results
Test
Electrode
Ipc
(mA/cm2)
Ipa
(mA/cm2)
Epc (V) Epa (V) Abs
(Ipa/Ipc)
ΔE (V)
Carbon
Control
-0.00466 0.000759 -0.9618 -0.394 0.162855 0.5678
4 Layer
Hybrid
-0.00364 0.001369 -0.9799 -0.4201 0.375996 0.5598
8 Layer
Hybrid
-0.00418 0.001861 -0.8617 -0.4759 0.445386 0.3858
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21. Interpretations
Carbon has little effect on reaction
Bismuth improves reversibility and peak
current
Increasing amount also improves
reversibility and peak current
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22. Future Studies
Why Carbon stabilizes Bismuth peaks
Scanning electron microscope
Characterize what’s occurring
Scale up production
Quantify improvement on VRFB
performance
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23. Timeline
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24. Thank You NSF!
Grant ID No. 0756921
EEC: 1004623
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25. References
1. http://www.energy.gov/science-innovation/energy-sources
2. http://www.ecology.com/2011/09/06/fossil-fuels-renewable-energy-resources/
3. http://www.messib.eu/assets/images/VRB_1_general_layout_VRFB.jpg
4. http://www.digsdigs.com/photos/fiedler-house-christmas-lights-1.jpg
5. http://img.wallpaperstock.net:81/windmills-wallpapers_22092_1600x1200.jpg
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26. References Continued
• 6. Zhenguo Yang, Jianlu Zhang, et al. “Electrochemical Energy Storage for Green Grid”
Chemical Reviews, 2010 Pacific Northwest National Laboratory, Richland, Washington 99352,
United States.
• 7. Dennis H. Evans, Kathleen M. O’Connell, et al. “Cyclic Voltammetry” Journal of Chemical
Education, 1983 University of Wisconsin-Madison, Madison, WI 53706.
• 8. David J. Suarez, Zoraida Gonzalez, et al. “Graphite Felt Modified with Bismuth Nanoparticles
as Negative Electrode in a Vanadium Redox Flow Battery” CHEMSUSCHEM, 2014 Wiley-VCH
Verlag GmbH & Co. KGaA, Weinheim.
• 9. Gareth Kear, Akeel A. Shah, and Frank C. Walsh. “Development of the all-vanadium redox flow
battery for energy storage: a review of technological, financial and policy aspects” International
Journal of Energy Research, 2012 Electrochemical Engineering Laboratory, Energy Technology
Research Group, School of Engineering Sciences, University of Southampton, Highfield,
Southampton SO17 1BJ, UK.
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27. Questions?
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