2 Section

Technological development (MCFC)

Technological development (MCFC) Material used now ANODE: Ni-Cr, Ni-Al CATHODE: LixNi(1-x)O ELECTROLYTE: Li2CO3/K2CO3 Na2CO3 MATRIX: -LiAlO2 ANODE CC: Ni/AISI310S/Ni CATHODE CC: AISI310S SEP. PLATE (AA): AISI310S SEP. PLATE (NAA): AISI310S/Al

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

Technological development (Electrochemical Performance) Reaction Rate Loss Electrochemical properties of Ni (for H2 oxidation reaction), and NiO (for O2 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) Resistance Loss Use of thin electrolyte layer decrease ionic resistance (gas separation problem) Use of electrolyte with low ionic resistance: Li2CO3/Na2CO3 has lower ionic resistance than Li2CO3/K2CO3 Use of materials for metallic components with higher corrosion resistance (thin corrosion layer with high electrical conductivity corrosion products)

Technological development (Electrochemical Performance) 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 (Operation time) Cathode dissolution LixNi(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)

Technological development (Operation time) CATHODE (+) NiO+CO2  Ni++ + CO3-- Ni++ MATRIX Ni++ +H2+ CO3--  Ni + H2O+CO2 e ANODE (-)

Technological development (Operation time) Metallic components corrosion Metallic components corrosion means mechanical property degradation b) a) 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)

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 -LiAlO2 to -LiAlO2 phase transition (gas composition) These changes on matrix material mean gas separation property degradation (increase of pore size, matrix not totally filled by electrolyte)

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 H2 and O2 will be possible (electrical performance degradation)

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

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

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

Lab level test (Operation time) Matrix filling level control

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

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

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

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

Lab level test (Operation time) GAS IN Thermocouple Fournace Alumina crucible Pressure load Porous Ni electrode filled with Li/K carbonate Metal sample (thickness: 0.3 mm) Porous Ni electrode filled with Li/K carbonate ANODIC GAS: H2 / CO2 (80/20) CATHODIC GAS: Air / CO2 T = 650 °C

Lab level test (Operation time) Trend to 40.000 hours

Lab level test (Cost reduction) Material analysis

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

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

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