Biogas provides an excellent means to convert waste to energy. It is an important technology widely applied in rural India with many significant installations also in the UK and Europe. Currently electricity is generally produced from biogas through thermal conversion; however, the electrical efficiency of this process is low. Converting biogas to electricity via fuel cell technology offers significant increases in efficieny, perhaps a factor of 2, and hence is a highly desirable technology. Some biogas installations do exist utiliing molten carbonate fuel cell technology; however, it is widely considered that Solid Oxide Fuel Cell Technology is the most promising future technology due to its much higher power density and its applicability to a wide range of scales. Here, we seek to improve the performance and durability of SOFC fuel electrodes for operation in biogas. Biogas is largely a mixture of CO2 and methane with quite large impurity contents of hydrogen sulphide. In this study, we investigate the performance and durability of some different SOFC concepts in fuel gas compositions directly relevant to biogas operation. The first strategy investigated will be to develop new perovskite and related materials for application as SOFC anodes that are resistant to coking and sulphur degradation. The second strategy to be investigated, relates to the utilisation of proton conducting perovskite to protect Ni and other electrocatalysts from coking and degradation. These and more conventional electrodes will be studied through sophisticating imaging techniques and electrochemcal performance testing. Promising concepts will be scaled up into significant cells, i.e. >10cm2 and rigourous testing performed. Test cells will be made and evaluated under different gas mixes probing both operation on startup in biogas and on prolonged operation utilising anode exhaust recirculate (containing steam and additional CO2) for internal reformation. Durability will be assessed up to 1000 hrs in appropriate biogas reformates and the degree of Sulphur scrubbing required, if any, assessed. Overall we seek solutions that could be applied to multi-kW scales of relevance decentralised and isolated operation. The UK will lead imaging and modelling, new anodes and performance testing, whereas India will lead proton conducting cermets and cell fabrication and scale up; however all activites involve significant cross-national activity. Two project workshops will be held in the UK and two in India and these will be linked to training events and outreach meetings open to the wider community. Each researcher will spend at least one month working in partner country laboratory on joint activity.

Fuel Cells continue to receive considerable attention as clean, highly efficient devices for the production of both electricity and, for some applications, high grade waste heat. However, considerable technical challenges remain for fuel cell to achieve greater penetration into commercial markets. It is worth emphasising the shift in research landscape within which the Supergen fuel cell consortium is operating. As fuel cell technology continues to mature, the fuel cell research community is being asked to place increasing emphasis on improving its fundamental understanding of materials behaviour under realistic operating conditions and duty cycles, especially where this relates to failure modes, and materials/cell degradation. Thus the work programme of this second phase will very much focus on generic and fundamental research, targeted onto real problems identified in discussion with our industry partners. This means that during this second phase, it will remain the case that the Supergen consortium will put an emphasis on knowledge transfer to industry, though of course patents will be filed where appropriate. It is then largely the responsibility of the industry partners to exploit this knowledge in the context of their own technology programmeThe proposed second phase of the Supergen fuel cell consortium refreshes the membership, with three new academics; Kucernak (Imperial), Brett (UCL) and Elliott (Cambridge) and with four academic teams continuing; Brandon (Imperial), Scott (Newcastle), Atkinson (Imperial) and Irvine (St Andrews). All three industry partners remain within the consortium for its second phase; Rolls-Royce Fuel Cell Systems, Ceres Power and Johnson Matthey, with the addition of a fourth new industry partner, Intelligent Energy. This new team maintains the consortium strength in Solid Oxide Fuel Cells, whilst adding significant extra capacity in Polymer Fuel Cells within both the industry and academic teams. This provides a shift in emphasis within the consortium to developing an improved understanding of failure modes and performance limitations within current fuel cell devices, and the need for greater scientific understanding to tackle these failure modes. In addition the consortium will continue to deliver its training courses in fuel cell science and engineering to consortium staff and students, external researchers to the consortium and to appropriate Doctoral Training Centres and to disseminate the work of the consortium (through publication and conference presentation, including an annual open conference) and to extend its international collaboration.

We plan to create a world-leading, multidisciplinary, UK Structural Ceramics Centre to underpin research and development of these highly complex materials. Structural ceramics are surprisingly ubiquitous not only in obvious traditional applications (whitewares, gypsum plaster, house bricks, furnace refractories, dental porcelains and hip/knee prostheses) but in hidden applications where their electrical behaviour is also important such as in computers, mobile phones, DVDs etc. Structural ceramics are enabling materials which underpin many key areas of the economy including: energy generation, environmental clean-up, aerospace and defence, transport and healthcare. Key areas where important developments can be made in energy generation include ceramics for plutonium immobilisation and for next generation nuclear reactor fuels, for ion conductors in solid oxide fuel cells, and for storage of hydrogen for the projected hydrogen economy. Porous ceramics need to be developed for heavy metal and radionuclide capturing filters to help with environmental remediation of soil, air and water and for storage of carbon captured from burning fossil fuels. The next generation of space shuttles and other military aircraft will rely on ceramic and composite thermal protection systems operating at over 2000C. Ceramic coatings on turbine blades in aircraft enable them to function at temperatures above the melting point of the metals alloys from which they are mostly made, and improved ceramics capable of operation at even higher temperatures will confer improved fuel efficiency with environmental benefits. Our troops need improved personal body & vehicle armour to operate safely in troubled areas and the latest generation of armour materials will use ceramic laminate systems but improvements always need to be made in this field. Ceramic are used increasingly for bone and tooth replacement with the latest materials having the ability to allow natural bone ingrowth and with mechanical properties close to natural bone. It is clear the improved understanding of the mechanical behaviour of ceramics, better and simpler processing and the ability to model structure-processing-property relations over many length scales will lead to significant benefit not just to the UK but to mankind. Our aim is to combine the capabilities of two internationally-leading Departments at Imperial College London (Materials and Mechanical Engineering) to form the Centre of Excellence. The Centre will act as a focal point for UK research on structural ceramics but will encourage industrial and university partners to participate in UK and international R&D programmes. 51 companies and universities have already expressed the wish to be involved with promised in-kind support at over 900K. Research activities will be developed in three key areas: -Measurement of mechanical properties and their evolution in extreme environments such as high temperatures, demanding chemical environments, severe wear and impact conditions and combinations of these.-High Temperature Processing and Fabrication. In particular, there is a need for novel approaches for materials which are difficult to process such as borides, carbides, nitrides, materials with compositional gradients and ceramic matrix composites (CMCs). -Modelling of the time-dependence of deformation and fracture of ceramics to predict the useful lifetime of components. The modelling techniques will vary from treating the material as a homogeneous block down to describing the atomic nature of the materials and links between these approaches will be established.In addition to providing the funding that will enable us to create the nucleus from which the centre can grow, mutually beneficial relations with industry, universities and research centres in the UK and abroad will be developed to ensure that a large group of researchers will remain active long after the period for which funding is sought will have ended.

Solid oxide fuel cells have the potential to greatly reduce carbon emissions in electricity generation because of their high conversion efficiency and suitability for distributed generation. Overall, this project will target the critical fuel cell issues of system cost and lifetime, including cell and stack cost, power density and affordability. The research will focus on the design, development and validation of novel components, sub-systems and integrated systems for RRFCS's initial system, a 1MW SOFC stationary power generation unit. Imperial College will contribute by developing new low-cost materials and geometries that are fundamental to the realisation of competitive fuel cells and stacks. This will involve using theoretical modelling at the atomistic level to identify promising new materials with the appropriate electronic properties. These will be synthesised and characterised in detail and finally the most promising ones will be evaluated in the RRFCS fuel cell structure.

INDUSTRIAL BACKGROUND: This proposal addresses a generic problem experienced in the manufacturing of following systems: (1) The solid oxide fuel cell manufactured by Rolls Royce Fuel Cell Systems Ltd (RRFCS) is a multi-layered ceramic system. Each layer is about 5-10 micrometres thick and has a different porosity and composition. The layers are screen-printed and sintered sequentially. (2) The TWI protective coatings, including optical coatings of indium-tin oxide, silica based protective coatings and anti-soiling coatings with fluorine incorporation, are made through a sol-gel and subsequent curing process. These coatings are typically less than 1.5 micrometres thick. (3) Piezoelectric films, between 1 and 50 micrometres thick, for micro electromechanical systems are often made by first depositing fine powders using electrostatic spraying, inkjet printing or dip coating and subsequently sintering. PROBLEM DEFINITION: The problem is how to avoid cracking of the films during the drying, curing and sintering steps. Elevated temperatures are used to consolidate the films. As temperature increases, the porous and liquid-filled films shrink first due to liquid evaporation and subsequently due to sintering or curing. The line-shrinkage can be as large as 20%. However the films cannot shrink freely in the plane of the film surface because of their bounding with the substrate, and with each other in multilayered films. The shrinking is highly constrained which leads to stresses and hence cracking in the films. RESEARCH ISSUES: The current systems are far from being optimised. It is almost impossible to achieve the optimisation using trial and error experiments because there are too many material and processing variables involved. There is an urgent need to develop a computer modelling capacity for the constrained shrinking and cracking phenomenon. However such a capacity does not yet exist mainly because of two reasons: (a) The existing modelling technique (the finite element method) requires the viscosities of the film material. These viscosities strongly depend on the microstructure of the material which changes dramatically as the film shrinks. These data are too difficult to obtain experimentally. (b) The science of predicting multi-cracking is premature.THE PROJECT TEAM: Supported by RRFCS and TWI, this proposal brings together three research groups at Universities of Leicester, Surrey and Cranfield and a futher research group in Germany to address these issues and to develop and validate a computer modelling technique. METHODOLOGY: In a recently completed PhD project, the investigators developed a ground breaking technique to model time dependent shrinkage deformation without knowing the viscosities. The proposed project is to build on this success and to further develop the technique for constrained shrinking and to include multi-cracking. The difficulty to deal with multi-cracks will be addressed using a so-called materials point method. This method was initially developed for plastic deformation but has been successfully extended to the multi-cracking problem in our pilot studies. The computer models will be developed around three experimental case studies. Three different experimental techniques will be used at Surrey, Crainfield and Wurzburg to measure the material data required in the model and to validate the model predictions. PROJECT IMPACT: This project will make it possible to optimise the design, material selection and processing parameters for solid oxide fuel cells, coatings and piezoelectric films. More generally the project will make a major impact on modelling the multi-cracking of brittle materials. Such problems include ballistic impact of ceramic armours, missile or explosive impact of civil structures and safety concerns of all glass structure