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2 Section. Technological development (MCFC) Material used now ANODE: Ni-Cr, Ni-Al CATHODE: Li x Ni (1-x) O ELECTROLYTE: Li 2 CO 3 /K 2 CO 3 Na 2 CO 3.

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Presentation on theme: "2 Section. Technological development (MCFC) Material used now ANODE: Ni-Cr, Ni-Al CATHODE: Li x Ni (1-x) O ELECTROLYTE: Li 2 CO 3 /K 2 CO 3 Na 2 CO 3."— Presentation transcript:

1 2 Section

2 Technological development (MCFC)

3 Material used now ANODE: Ni-Cr, Ni-Al CATHODE: Li x Ni (1-x) O ELECTROLYTE: Li 2 CO 3 /K 2 CO 3 Na 2 CO 3 MATRIX:  -LiAlO 2 ANODE CC: Ni/AISI310S/Ni CATHODE CC: AISI310S SEP. PLATE (AA): AISI310S SEP. PLATE (NAA): AISI310S/Al

4 Materials actually used in MCFC are suitable to have high electrochemical performance and long operation time In view of Fuel Cell market, it is still possible to think to improve materials to obtain higher performance, longer operation time and low cost Technological development (MCFC)

5 Technological development (Electrochemical Performance) Reaction Rate Loss mainly depends on materials used for anode and cathode (catalyst property) Resistance Loss mainly depends on ionic resistance of electrolyte and electronic resistance of anode, cathode, metallic components included corrosion layers Gas Transport Loss mainly depends on anode and cathode materials morfology Reaction Rate Loss mainly depends on materials used for anode and cathode (catalyst property)

6 Reaction Rate Loss Electrochemical properties of Ni (for H 2 oxidation reaction), and NiO (for O 2 reduction reaction) are very high However, limited improvements should be possible by addition of catalyst in standard anode, cathode materials (Cost?, CO use?) Technological development (Electrochemical Performance)

7 Resistance Loss Use of thin electrolyte layer decrease ionic resistance (gas separation problem) Use of electrolyte with low ionic resistance: Li 2 CO 3 /Na 2 CO 3 has lower ionic resistance than Li 2 CO 3 /K 2 CO 3 Use of materials for metallic components with higher corrosion resistance (thin corrosion layer with high electrical conductivity corrosion products) Technological development (Electrochemical Performance)

8 Gas Transport Loss Porosity, surface area of anode and cathode are suitable to obtain low gas transport loss (bi-modal morfology of cathode) However improvement should be possible with higher surface area (nanomaterials?) Technological development (Electrochemical Performance)

9 Technological development (Operation time) Cathode dissolution Li x Ni (1-x) O has not completely chemical stability in working conditions Precipitation of Ni in Matrix can produce a direct electronic contact between anode and cathode Internal current flow means electrical performance decay Use of more chemical stable materials should be useful (catalyst for cathodic reaction, high electronic conductivity)

10 CATHODE (+) ANODE (-) MATRIX Ni ++ NiO+CO2  Ni ++ + CO3 -- Ni ++ +H2+ CO3 --  Ni + H 2 O+CO 2 Technological development (Operation time) e

11 Metallic components corrosion Metallic components corrosion means mechanical property degradation Anode current collector section OM analysis. a) Before operation b) After operation:it is possible to see Ni coating degradation (lower corrosion protection), and carburisation of AISI310S grains (lower mechanical property) a) b)

12 Technological development (Operation time) Porous components micro-structural degradation Porosity, pore size distribution, surface area and morfology of anode and cathode material change in time due to axial load and sintering (Anode) These changes on electrodes materials mean electrochemical performance degradation (P=0) Porosity, pore size distribution, surface area and morfology of matrix material could change in time due to  -LiAlO 2 to  -LiAlO 2 phase transition (gas composition) These changes on matrix material mean gas separation property degradation (increase of pore size, matrix not totally filled by electrolyte)

13 Technological development (Operation time) Electrolyte loss Electrolyte loss depends on metallic materials corrosion, vapour phase in gas stream When electrolyte quantity is not enough to have totally filled matrix, direct contact of H 2 and O 2 will be possible (electrical performance degradation)

14 Lab level test (Performance) Single cell test Single cell is useful to test electrical performance in lab scale MCFC

15 Lab level test (Performance) Activation Pol. Ohmic Pol. Concentration Pol.

16 Lab level test (Performance) Gas analysis In-out single cell gas analysis are performed to check gas utilisation and possible gas reaction through matrix

17 Lab level test (Operation time) Matrix filling level control

18 Lab level test (Operation time) Lab stack test Lab size stack is useful to test electrical performance of more cells in stack configuration

19 Lab level test (Operation time) Post test analysis SEM-EDS

20 ANODE, CATHODE, MATRIX SEM ANALYSIS (Micro- structural change) Lab level test (Operation time)

21 ANODE, CATHODE, MATRIX PORE SIZE ANALYSIS (Micro- structural change) Lab level test (Operation time) Porosity reduction Pore size distribution change

22 Lab level test (Operation time) ANODIC GAS : H 2 / CO 2 (80/20) CATHODIC GAS : Air / CO 2 T = 650 °C GAS IN Thermocouple Fournace Metal sample ( thickness: 0.3 mm) Alumina crucible Porous Ni electrode filled with Li/K carbonate Pressure load

23 Trend to hours Lab level test (Operation time)

24 Material analysis Lab level test (Cost reduction)

25 Tape Casting Material analysis Drying Material analysis Binder burn out and sintering Lab level test (Cost reduction)

26 RAW MATERIALS ANALYSIS SEM XRD GRANULOMETRY Lab level test (Cost reduction) Use of cheaper raw materials

27 Conclusion Fuel cell is an electrochemical device that converts energy of a chemical reaction into electricity without any kind of combustion and with high conversion capability and low environmental emissions. Molten Carbonate Fuel Cells don’t use expensive catalytic material (Platinum); it can works using CO (reformed natural gas); Operating temperature (650 °C) permit use of stainless steel for metallic components fabrication MCFC market entry depends on operating life increase and cost reduction. Both points strongly depend on materials used in Fuel Cell preparation


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