A novel dual chamber (DC) measurement cell has been implemented for simultaneous monitoring of crystallographic and electrochemical (EC) properties of Ni-Ce0.9Gd0.1O2-delta (Ni-GDC) solid oxide fuel cell (SOFC) anode at different fuel cell polarizations. The influence of system parameters (temperature, oxygen partial pressure in anode compartment and oxide ion flux through the electrolyte membrane from the cathode to the anode) on the crystallographic structure of GDC and redox performance of Ni has been studied. The oxide ion flux through the membrane from cathode to anode leads to increase of oxygen partial pressure in anode layers close to electrolyte. Increase of oxygen partial pressure leads to decrease of unit cell volume of the GDC lattice. The observed average change of GDC lattice parameter was 0.0147 angstrom V-1 at 800 degrees C. The oxidation of Ni caused by oxide ion flux at high fuel cell loads has been detected electrochemically but not from XRD results. (C) The Author(s) 2018. Published by ECS.