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Interdispersed YSZ-Zn doped CeO2-NiO-Ag Composites for Anode Supported Intermediate
Temperature Solid Oxide Fuel Cells
Bhasker Soni and Somnath Biswas**Email: [email protected]
Department of Physics, The LNM Institute of Information Technology (Deemed University)Jaipur – 302031, India
4th ICAER, IIT Bombay, 20131
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Lecture Plan
Introduction Experimental details Results Future Work Conclusions
4th ICAER, IIT Bombay, 2013
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Introduction
Global energy requirements are increasing rapidly
Energy crisis
Green house effect
Global warming
Limited energy sources : Conventional and non-conventional
Drawbacks with the present power technologies
Lack of efficient technology
Fuel cells technology
4th ICAER, IIT Bombay, 2013
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Introduction
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Introduction
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Introduction
4th ICAER, IIT Bombay, 2013
Presently used technology
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Introduction
Fuel cell : An electrochemical device that converts energy produced from a chemical reaction into electrical energy.
This chemical reaction is not a combustion process
Chemical Energy Electrical Energy Working :
Anode: 2H2 + 2O= =4e- + 2H2O
Cathode: O2 + 4e- = 2O=
Over All: 2H2 + O2 = 2H2O
Electricity is generated with H2O as byproduct.
Animation taken from Solid state energy conversion Alliance (SECA)
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Introduction
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PEMFC (proton exchange membrane) DMFC (direct methanol) AFC (alkaline) PAFC (phosphoric acid) MCFC (Molten Carbonate) SOFC (solid oxide)
Types of Fuel Cells
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Introduction
SOFC : Solid Oxide Fuel Cell. Working :
Anode: 2H2 + 2O= =4e- + 2H2O
Cathode: O2 + 4e- = 2O=
Over All: 2H2 + O2 = 2H2O
Electricity is generated with H2O as byproduct.
4th ICAER, IIT Bombay, 2013
Advantages High conversion efficiency 45%(up to *85% energy efficiency when combined with gas turbine). Combined heat and power. No need for electrolyte management. Ample fuel flexibility (Nat. gas/methane fuelled). Non Polluting - no NOx/SOx
Long life, modular.
Quiet in operation. Load flexible. Low cost ceramic and non noble metal materials.
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SOFCs
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Disadvantages High operating temperature (800 °C – 1000 °C). Less material selection options. Thermal stress. Degradation and delamination. Long start up time. Difficulty in stacking cells.
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Experimental Details
4th ICAER, IIT Bombay, 2013
Synthesis
Synthesis of nanoparticles
Synthesis of YSZ-CZO-NiO-Ag nanocomposites.
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Experimental Details
C
Synthesis of nanoparticles of 8YSZ, Ni:NiO, Zn doped CeO2(CZO)
A B
Magnetic Stirrer
Nitrate solutions of
Y(NO3)3·6H2O
ZrO(NO3)2·H2O
Ni(NO3)2.6H2O
Ce(NO3)3·6H2O
Zn(NO3)3·6H2O
Sol-gel type chemical precursor
method. pH: Basic medium Reaction Temperature: 60 – 70°C Amorphous dried precursor. Calcined at 400°C,500°C and 600°C.
4th ICAER, IIT Bombay, 2013
Experimental Details
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20 30 40 50 60 70 80
20 30 40 50 60 70 80
20 30 40 50 60 70 80
(c)
(b)
Diffraction Angle, 2 (degree)
(1
11)
(200
) (220
)
(311
)
(222
)
(400
)
(331
)
(420
)
(a)
(222
)
(311
)
(220
)
(200
)
(111
)
(220
)
(200
)
(111
) NiO
Ni
Inte
nsit
y (a
rb. u
nit)
(400
)
(311
)(220
)
(200
)
(111
)
Synthesis of nanoparticles of 8YSZ, Ni:NiO, Zn doped CeO2(CZO)
Fig. 1 XRD plots of (a) 10 mol% CZO, (b) 8 mol% YSZ, and (c) Ni : NiO (core-shell) nanoparticles obtained after heat treatment of the corresponding precursors at 400°C, 500°C and 600°C, respectively in ambient air .
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Experimental Details
(a) (b) (c) (d)
Fig. 2 Typical HRTEM images of (a, b) 8 mol% YSZ, (c) 10 mol% CZO, and (d) Ni:NiO nanoparticles.
4th ICAER, IIT Bombay, 2013
Experimental Details
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Synthesis of nanoparticles of 8YSZ, Ni:NiO, Zn doped CeO2(CZO)
(a) (b)
Fig. 3 FESEM images of (a) 10 mol% CZO and (b) 8 mol% YSZ nanoparticles.
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Experimental Details
SampleCode
YSZ (vol%)
CZO (vol%)
Ni : NiO (vol%)
A 20 20 60
B 25 25 50
C 30 30 40
D 35 35 30
Structural Electrical
Series of composite samples. Ball milled for 5 h. Starch as pore former. Ball to Powder ratio 10 : 1.
4th ICAER, IIT Bombay, 2013
Table 1. Compositional details of YSZ-CZO-Ni:NiO composites.
Synthesis of YSZ-CZO-NiO-Ag nanocomposites
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Experimental Details
SampleCode
YSZ (vol%)
CZO (vol%)
Ni : NiO (vol%)
A 20 20 60
B 25 25 50
C 30 30 40
D 35 35 30
Structural Electrical
TEC of YSZ : 10.5 x10-6 K-1. TEC of Ni : 13.0 x10-6 K-1. TEC of CeO2 : 12.58 x10-6 K-1 TEC of Ag : 18.0 x10-6 K-1.
4th ICAER, IIT Bombay, 2013
Table 1. Compositional details of YSZ-CZO-Ni:NiO composites.
Synthesis of YSZ-CZO-NiO-Ag nanocomposites
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Experimental Details
4th ICAER, IIT Bombay, 2013
20 30 40 50 60 70 80
Inte
nsi
ty (
arb
. u
nit)
Diffraction Angle, 2 (degree)
�
�
�
(220
)
(200
)(2
00)
(111
)
(200
)(1
11)
(220
) (200
)
(311
)
(311
) (220
)
(311
)(2
20)
(222
)
(111
)
(D)
(B)
(A)
(C)
NiO
CZO
YSZ
�
Ni
Fig. 4 XRD plots of YSZ-CZO-Ni:NiO nanocomposites of compositions as shown in Table 1.
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Experimental Details
Porosity measurement using ASTM C20 technique
Sample is oven dried at 110 C till constant weight is achieved.⁰
Submerged in boiling water for 4 h.
When suspended in water, the weight is measured to calculate specific
gravity.
Porosity (P,%) = (W – D)/V x 100 = 38.4% (sample A)
= 38.7% (sample C)
where, W = saturated weight
D = dry weight
V = volume of sample
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Future Work
Oxygen Permeability.
Impedance Spectroscopy.
I-V and I-P characteristics : DC Four Probe.
Mechanical properties : Ductility and strength, Elastic properties, CTE,
Poisson's ratio, creep analysis etc.
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Conclusions Composite anode materials of YSZ-CZO-Ni:NiO for intermediate temperature
SOFCs have been developed by mechanical attrition method.
From XRD studies, the crystal structure of YSZ, CZO and Ni:NiO has been confirmed to be cubic in nature.
FESEM and HRTEM micrographs reveal the fine structure of the particles.
Electrical and electro-chemical analyses of the samples are currently being performed.
Successful development of this material would decrease the polarization losses at anode and aid in enhancing the cell performance at lower temperatures.
4th ICAER, IIT Bombay, 2013
The authors sincerely thank (i) Tata Institute of Fundamental Research (TIFR), Mumbai (ii) UGC-DAE Consortium for Scientific Research, Indore, (iii) Sathyabama University, Chennai, and (iv) Sophisticated Analytical Instrument Facility (SAIF), North-Eastern Hill University (NEHU), Shillong for providing us the instrumental facilities.
We also thank The LNM Institute of Information Technology for their financial support to carry out the research work.
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Acknowledgements
THANK YOU
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