Advanced SOFC technologies for low carbon, energy efficient and affordable power
Lead Research Organisation:
University of St Andrews
Department Name: Chemistry
Abstract
Conventional Ni-YSZ anodes have limitations with respect to their durability under real fuel environments. Some of the oxide anodes that are currently under investigation, such as the LSCM family of materials at St Andrews promise to give better tolerance to C-deposition and improved redox stability on cycling. However, their integration into the IP-SOFC has to take account of their lower electronic conductivity as well as the different ceramic processing requirements. Work in this package will seek to exploit the continuing advances in materials elsewhere and incorporate these in the IP-SOFC design. On the anode-side, oxides such as the lanthanum strontium chromite manganites, offer the potential to improve the durability of the anode towards sulphur and carbon-deposition and to improve its stability on redox cycling. This would have benefits in improving stack durability as well as potentially allowing a major simplification of the system. The project will seek to implement novel anode materials into the integrated planar design and to seek and develop new alternative materials for use as anodes and anodic current collection layers. Materials will be investigated by solid state techniques and processing optimised for screen printing to achieve integrated planar modules for performance testing in different fuels. Susceptibility to sulphur poisoning and hydrocarbon cracking will be investigated.
Organisations
- University of St Andrews (Lead Research Organisation)
- ESL Europe (Collaboration, Project Partner)
- Scitek Consultants Ltd (Collaboration)
- MEL Chemicals Inc (Collaboration)
- Rolls Royce Group Plc (Collaboration)
- Rolls-Royce (United Kingdom) (Project Partner)
- SCITEK Consultants (United Kingdom) (Project Partner)
- Luxfer Group (United Kingdom) (Project Partner)
Publications
Boulfrad S
(2010)
Adhesion and Percolation Parameters in Two Dimensional Pd-LSCM Composites for SOFC Anode Current Collection
in Advanced Functional Materials
Boulfrad S
(2011)
NbTi0.5Ni0.5O4 as anode compound material for SOFCs
in Solid State Ionics
Cassidy M
(2009)
Integration of Oxide Anodes into the Rolls-Royce IP-SOFC Concept
in Fuel Cells
Description | During the course of this programme advanced oxide based anodes have been integrated into the IP-SOFC design at a stack repeat unit level. Cells were manufactured and tested at St Andrews. Through careful engineering of the microstructure of an anode current collector (ACC), a thin composite layer was developed that results in a conductive layer which is deposited in a single screen printing operation. This composite consists of a mixture of the electronic conducting phase and a proportion of LSCM anode material. The presence of the LSCM promotes the formation of a physical bridge between the ACC and anode during co-firing thereby preventing delamination that was observed during earlier trials. The electrochemical performance of the anode has been enhanced by the development of a technique to introduce small amounts (5wt% maximum) of Ni catalyst. This is accomplished by a nitrate coating technique where the raw LSCM powder is covered with a thin catalyst coating. This coated LSCM can then be processed using standard screen printing and firing techniques. On introduction of fuel gas to an anode layer of this type the NiO on the surface of the LSCM reduces to form nanoscale metallic Ni particles which aid the catalytic activity. As these particles are supported on the LSCM backbone and are not required either for electrical conduction or structural integrity many of the redox issues of having Ni in the anode can be avoided. Combining both of the above developments has resulted in LSCM anode performances comparable to those of standard anode materials (Ni-YSZ cermets) have been attained. Recent tests have shown good open circuit voltages higher than 1V indicating a well sealed test piece with a crack free gas tight electrolyte. AC impedance testing has shown values for Rs and Rp. That compare well with those recorded for standard materials sets. Cells demonstrated very good stability after a number of redox cycles, thermal cycles and combined thermal/redox cycles, maintaining good open circuit voltage and minimal performance drop. |
Exploitation Route | This work has shown that LSCM based cathodes can be successfully integrated into the IP-SOFC design and manufacturing windows. With careful engineering of composition and microstructure performances have been exhibited which match conventional Ni cermet based anodes in standard conditions. Unfortunately it was not possible to expand the testing to larger units using more realistic fuels at RRFCS as initially planned, however supplementary infrastructure supplied by RRFCS towards the end of the programme is currently being installed at St Andrews which will allow us to carry out this work in the future. |
Sectors | Energy Environment |
Description | Led to election as Chairman of the Scottish Hydrogen and Fuel Cell Association (SHFCA). |
First Year Of Impact | 2008 |
Sector | Energy |
Impact Types | Policy & public services |
Description | ESL Europe |
Organisation | ESL Europe |
Country | United Kingdom |
Sector | Private |
Start Year | 2007 |
Description | MEL Chemicals |
Organisation | MEL Chemicals Inc |
Country | United States |
Sector | Private |
Start Year | 2007 |
Description | Rolls-Royce Fuel Cell Systems Ltd |
Organisation | Rolls Royce Group Plc |
Department | Rolls-Royce Fuel Cell Systems Limited |
Country | United Kingdom |
Sector | Private |
Start Year | 2007 |
Description | Scitek Consultants Ltd |
Organisation | Scitek Consultants Ltd |
Country | United Kingdom |
Sector | Private |
Start Year | 2007 |