Multiscale in-situ characterisation of degradation and reactivity in solid oxide fuel cells

Lead Research Organisation: University of St Andrews
Department Name: Chemistry

Abstract

As alternative and low carbon energy technologies are of increasing international importance there is considerable debate as to the most appropriate technology solutions for power generation. For a distrubted generation scenario with power output in the range of kW to MW the solid oxide fuel cell (SOFC) is a leading contender, with development undertaken by many international companies. One of the areas of concern with new technologies is the lifetime of the device and as SOFCs operate at elevated temperatures any degradation of components may be accelerated. Due to the complexity of these devices there has been limited scope to analyse the operation of the SOFC in-situ, and from this determine mechanistic information on degradation processes. It is the aim of this proposal to tackle this challenge.Degradation and reactivity of solid oxide fuel cells may be characterised by processes occuring on a variety of length scales, from chemical reactivity and diffusion processes on the atomic scale through surface chemsitry, stress in functional layers and thermal management over mm and cm. Each of the processes contributes to the overall cell degradation, but may evolve differently depending on the functional component concerned - hence anode and cathode processes will be significantly different. As these are complex devices characterising these processes and the origin of them is challenging and currently results from post-mortem analysis. Whilst this is one route to understanding the failure of devices, an in-situ characterisation under operating conditions will provide detailed direct understanding. Our approach is to develop a combination of complimentary techniques that will allow detailed study of device operation using diffraction, spectroscopy, ion scattering, modelling and emissivity measurements. We will tackle known degradation issues in fuel cells including carbonate and Cr poisoning of cathodes, carbon formation on anodes and electrode delamination and will interact strongly with the UK Supergen Fuel Cells programme. As a result of this programme we will be able to inform industrial partners of mitigation strategies to minimise device degradation and use this information in development of new materials.
 
Description The simultaneous in-situ structural and electrical measurements allowed us to better understand processes like nanocatalyst exsolution on the surface of the perovskites or transport mechanisms in alkaline earth hydrides, for developing energy materials.
Exploitation Route The development of an in situ measurement rig is currently helping performing similar experiments on various materials and can be further improved for more complex experiments
Sectors Chemicals,Energy

 
Description It is an early stage for these results to produce a non-academic impact, but an increase in number of applications and neutron diffraction experiments on perovskite materials capable of exsolution has been observed
First Year Of Impact 2014
Sector Chemicals,Energy
 
Title Data underpinninng - Enhancement of redox stability and electrical conductivity by doping various metals on ceria, Ce1-xMxO2-d (M=Ni, Cu, Co, Mn, Ti, Zr) 
Description  
Type Of Material Database/Collection of data 
Year Produced 2015 
Provided To Others? Yes  
 
Description Rig development for In situ testing at STFC-ISIS 
Organisation Science and Technologies Facilities Council (STFC)
Department ISIS Neutron and Muon Source
Country United Kingdom 
Sector Academic/University 
PI Contribution Collaborating with instrument engineers at ISIS for design, execution, commisioning and testing of and in-situ rig capable of simultaneous sample characterisation using neutron diffraction and electrical measurements in various atmospheres
Collaborator Contribution The instrument engineers at ISIS were advising in all execution steps of this in situ testing rig
Impact The development of this testing capability allowed us to perform very valuable diffraction studies on nanocatalyst exsolution from perovskites and H/D exchange reactions on alkaline earth hydrides. A couple of manuscripts are in preparation here based on the results obtained in these studies.
Start Year 2013