A Numerical Model for Direct Carbon Fuel Cells Based on Hybrid Lattice Boltzmann and Finite Difference Methods

This paper presents 2D simulations of Direct Carbon Fuel Cells (DCFC) performance. The impact of the operating parameters, such as porosity of the cathode and gas inlet concentration (dioxygen), on the latter performance is investigated. The in-house numerical code based on the Lattice-Boltzmann technic with the Multiple Relaxation Time (MRT) scheme was utilized to calculate the gas flow field inside the various components of the fuel cell. The conservation equations for species were solved using finite differences. Specifically, on the cathode side, dioxygen and carbon dioxide diffused from the cathode gas channel through the cathode towards the cathode/electrolyte interface. At the three-phase boundaries, the oxygen and carbon dioxide react by consuming electrons provided by the external circuit, resulting in the generation of carbonate ions. The results of the present simulations demonstrate that a high cathode porosity and high dioxygen concentration have a direct and positive effect on the overall performance of the DCFC.