Nd-Nickelate (NNO), Nd1.95NiO4+delta, an alternative solid oxide fuel cell cathode material, has been imaged and mapped in 3D using synchrotron-based x-ray nanotomography. The NNO cathode material, which suffered from silicon contamination during fabrication, was found to contain the desired NNO, plus two distinct poisoning phases. The likely composition and description of the poisoning phases are presented, as well as a detailed description of the microstructural mapping and material characterization. The insulating poisoning phases are likely to have deleterious implications for the cell, as they have a tendency to form a coating layer on the NNO surface, significantly decreasing its active area. Additional losses may be expected due to the poisoning phases inhibiting ionic and electronic transport pathways, increasing cathode polarization resistance. (C) 2013 Elsevier B.V. All rights reserved.