Typical microstructures of LSM/YSZ NiO/YSZ Ni/YSZ composite electrodes are simulated by the discrete element method The numerical microstructures are generated by taking into account in a realistic manner the sintering process This allows complex microstructures such as Mayers or microstructures containing pore formers to be obtained NiO particles in the NiO/YSZ composite electrodes are reduced to Ni Reduction is carried out with the discrete element formalism which allows particle rearrangement to be taken Into account We show that the mechanical percolation of the YSZ phase plays an important role during the reduction of NiO The various numerical microstructures generated by sintering and reduction are analyzed to evaluate important microstructural features such as macroscopic porosity pore surface area and Triple Phase Boundary length (c) 2010 Elsevier BV All rights reserved