Ethanol Fuel as Portable Power Source in Alkaline Fuel Cells Prof. Shingjiang Jessie Lue Chair and...
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Transcript of Ethanol Fuel as Portable Power Source in Alkaline Fuel Cells Prof. Shingjiang Jessie Lue Chair and...
Ethanol Fuel as Portable Power Source in Alkaline Fuel CellsProf. Shingjiang Jessie Lue
Chair and professor, Department of Chemical and Materials Engineering
Group leader, Green Technology Research Center
Chang Gung University, Taiwan
Fuel cell cars powered by bioethanol: Green energy
H2 + O2 H2O + i
Chemical energy electricity Oxidation/combustion of
fuels Spontaneous reaction Catalysts speed up reaction
rate (more electrons generated; higher electrical current)
Various process steps for biomass conversion to ethanol and co-products
Badwal et al., Appl. Energ. 145 (2015) 80.
Various sources of ethanol, energy output/ input ratios and commercial statusSource type Sources Energy output/input ratio Commercialization stage
Food crops CornWheatBarleySugarcaneSugar beetCassavaSorghum
Corn: 1.4, 2a and 2.8b
Sugarcane:~8 (Brazil) Sugar beet: 2
Commercial plants of ethanol mainly from corn (US) and sugarcane
Inedible parts of plant-cellulosic ethanol
Corn stoverWheat strawRice strawSugarcane bagasse
5.2–5.545.2–32
Pre-commercial stage, pilot scale or demonstration plants with subsidies and local government support
Cellulosic ethanol-others Switch grassPoplarForest residueAgricultural wasteMunicipality waste
2–36 Pilot scale or demonstration plants with subsidies and local government support
a For ‘‘a dry grind ethanol plant that produces and sells dry distiller’s grains and uses conventional fossil fuel power for thermal energy and electricity’’.b For ‘‘a dry grind ethanol plant that produces and sells dry distiller’s grains and uses’’ 50% biomass power.
Badwal et al., Appl. Energ. 145 (2015) 80.
Potential fuels: hydrogen and alcohols
Badwal et al., Appl. Energ. 145 (2015) 80.
Electrochemical reactions involved in various types of alcohol fuel cells
Badwal et al., Appl. Energ. 145 (2015) 80.
Proton- and hydroxide-conducting DEFCs
C2H5OH + 3O2 → 2 CO2 + 3 H2O Eo=1.14 V, ΔGo= -1325 kJ mol–1
Disadvantages:Ethanol cross-over -- Fuel loss -- Mixed cell potentialExpensive Pt based catalystProton exchange membrane
Advantages:Faster ethanol oxidation rate in alkaline mediaCan use less expensive non-Pt catalystsDirection of OH− anion motion opposes ethanol permeability: less EtOH cross-overEasy water management
C2H5OH + 3O2 → 2 CO2 + 3 H2O Eo=1.14 V, ΔGo= -1325 kJ mol–1
Acid Alkaline
Front. Energy Power Eng. China 4 (2010) 443; J. Membr. Sc. 367 (2011) 256.
Electrochemical performance
Polarization curve (V-I curve)
Voc (open-circuit voltage): governed by catalytic activity and fuel cross-over rate
Ohmic loss: governed by cell electric resistance (esp. membrane electrolyte)
Power density curve (P-I curve)
P=VI
Pmax (peak power density): more reproducible than Voc
Pmax: indicator of fuel cell performance
http://www.intechopen.com/
DEFC performance reported in literatures
An et al., Renew. Sust. Energ. Rev. 50 (2015) 1462.
DEFC prototype stack
Badwal et al., Appl. Energ. 145 (2015) 80.
10 kW DEFC stack (by NDC Power)1 kW DEFC stack (by NDC Power)
Our Research Focuses
Prepare and synthesize frontier materials for energy applicationsSolar cell
Fuel cell
Lithium-air battery Membrane Requirements : High conductivity and low fuel permeability
Working Mechanism of Alkaline Alcoholic Fuel Cells
O2+H2O
CO2+H2O
C2H5OH+KOH
Nanocomposite Membrane
C2H5OH
Anode: C2H5OH+12OH-→2CO2+9H2O+12e-
Cathode: 3O2+6H2O+12e-→12OH- Overall: C2H5OH+3O2→2CO2+3H2O
Hydroxide transport mechanisms
Vehicular diffusion
Hopping mechanism
Surface diffusion
Polymer/nano-fillersPolymer/carbon nano-tubesPolymer/anion-
exchange moiety
Our Membrane Electrolyte Development Strategy
PVA/CNTPBI/CNT
Q-PVA/Q-chitosan
Blend with Q-chitosannanoparticles
J. Polym. Sci. Phys. 51 (2013) 1779J. Membr. Sci. 376 (2011) 225J. Power Sources 202 (2012) 1J. Power Sources 246 (2014) 39
J. Membr. Sci. 485 (2015) 17
Nafion/GOPBI/GO
J. Membr. Sci. 493 (2015) 212
Pristine GO
GO on Nafion
Single cell assembly and test
MEA (membrane electrode assembly) Anode (catalyst on gas diffusion electrode): Pt-Ru/C or non-Pt/C on carbon cloth Membrane electrolyte Cathode (catalyst on gas diffusion electrode): Pt/C or non-Pt on carbon cloth
Fuel/KOH
J. Membr. Sci. 464 (2014) 43.
DEFC performance: PTFE/sSEBS
DEFC at 30 and 60ºC
Pmax = 17 mW cm-2
at 30ºC
at 60ºC
Pmax = 7.6 mW cm-2
Anode: PtRu/C (6 mg cm-2)Cathode: Pt/C (5 mg cm-2)
Sulfonated styrene-ethylene-butylene-styrene block copolymer
J. Membr. Sci. 493 (2015) 212.3 M ethanol at 80ºC
DEFC performance: Graphene oxide (GO)/Nafion
Pmax = 35 mW cm-2
Anode: PtRu/C (6 mg cm-
2)Cathode: Pt/C (5 mg cm-
2)
(a)
(b)
(c)
(d)
ADEFC performance: polyvinyl alcohol/carbon nanotubes (PVA/CNT)
ADEFC in 5 M KOH
at 30ºC
PVA/CNT
at 60ºC
J. Power Sources, in review.
Fractional free volume: 2.48 to 3.53% (containing CNT)
Pmax = 33 mW cm-2 Pmax = 65 mW cm-2
Anode: PtRu/C (6 mg cm-2), cathode: Pt/C (5 mg cm-2)
J. Membr. Sci. 485 (2015) 17.3 M ethanol in 5 M KOH
Anode: PtRu/C (6 mg cm-2)Cathode: Pt/C (5 mg cm-2)
Anode: PdCeO2/C (6 mg cm-2)Cathode: CuFe/C(5 mg cm-2)
ADEFC performance: Q-PVA/Q-chitosan
EtOH
Pmax = 20 mW cm-2
Pmax = 59 mW cm-2
J. Membr. Sci. In preparation.3 M ethanol in 5 M KOH
ADEFC performance: GO/PBI
Anode: PtRu/C (6 mg cm-2)Cathode: Pt/C (5 mg cm-2)
Anode: PdCeO2/C (6 mg cm-2)Cathode: CuFe/C 5 mg cm-2)
Pt-based catalyst Non Pt-based catalyst
Pmax = 120 mW cm-2 Pmax = 100 mW cm-2
Our Alkaline Fuel Cell Performance
Conclusion Ethanol is a potent fuel source for direct alcohol
fuel cells We have designed various nanocomposite
electrolytes for acidic and alkaline DEFCs Our alkaline DEFC reached peak power density of
120 mW cm-2
Continued investigation on stable, high-performance catalysts on ethanol oxidation and oxygen reduction reactions is in strong demand
An et al., Renew. Sust. Energ. Rev. 50 (2015) 1462.
Acknowledgements
Ministry of Science and Technology, Taiwan Chang Gung Hospital Project Mr. Bor-Chern Yu, Mr. Guan-Ming Liao, Ms. Pin-
Chieh Li, Ms. Jia-Shiun Lin, Dr. Hsieh-Yu Li, Dr. Chao-Ming Shih, Dr. Rajesh Kumar
Thank you for your attention!