In recent years, developments in tomography tools have provided unprecedented insight into the microstructure of electrodes for solid oxide fuel cells, enabling researchers to establish direct links between electrode microstructure and electrochemical performance. Here we present results of high resolution, synchrotron X-ray nano computed tomography experiments, which have enabled microstructural characterisation of a mixed ionic electronic conducting lanthanum strontium cobalt iron oxide (LSCF) cathode with sub-50nm resolution at operating temperature. Using the uniquely non-destructive nano-CT platform, it is possible to characterise microstructural evolution processes associated with heating and operation in-situ. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3615824] All rights reserved. ; Times Cited: 0