Assessment of the intricate nickel-based anodic reactions mechanism within a methanol fed solid oxide fuel cell based on a co-ionic conducting composite electrolyte

We propose here a comprehensive modelling approach to predict the intricate anodic electrochemical reactions within a direct methanol fed solid oxide fuel cell based on a H+/O2- dual conducting composite electrolyte. We assess the effect of the ionic transference number (t(n)) on open circuit voltage of the cell operating at 650 degrees C, 700 degrees C and 750 degrees C to determine an optimum t(n). The modelling proposes three electrochemical reactions scenarios associated to direct methanol fed solid oxide fuel cell i.e. (1) full methanol oxidation (2) total methanol reforming and subsequent light gases oxidations (3) mixed oxidation of unconverted methanol and light gases. Simulation results prove the capability of scenario 2 to predict adequately the anodic reactions mechanism indicating the total reforming of methanol over the Nickel-samarium doped ceria anode at 650 degrees C and the electrochemical oxidation of around 1% and 7% of methanol molecules at 700 degrees C and 750 degrees C, respectively. Furthermore, scenario 1 exhibits the highest efficiency similar to 50% in the temperature range between 650 degrees C and 750 degrees C with limited fuel utilization similar to 39%. Nevertheless, the fuel utilization increases to 30% and 70% at 650 degrees C and 750 degrees C respectively, when using scenario 3.