Development of liquid antimony anode-based fuel cells: Effects of reaction-induced convection on mass transfer and electrochemical performance

[Display omitted] •A model for Sb-Sb2O3 two-phase convection in liquid antimony anode-based fuel cells.•Simulating the reaction-induced convection and its influence on cell performance.•Evaluating the losses caused by different cell components during Sb2O3 accumulation.•A cell structure to decouple Sb2O3 accumulation regions from electrochemical sites. The Liquid Antimony Anode–based Solid Oxide Fuel Cell (LAA-SOFC) represents a promising energy conversion approach for generating power using complex fuels. This study addresses the relationship between the liquid–liquid distribution of Sb-Sb2O3 and the corresponding electrochemical performance of LAA-SOFC. A 2-D axisymmetric model that incorporates the two-phase flow of Sb-Sb2O3, alongside the electric field and the chemical/electrochemical reactions is successfully developed to explore the reaction and convection characteristics of LAA in LAA-SOFC under gravitational influence. The model results indicate that the density disparity between Sb and Sb2O3 can drive convection and stratification with Sb2O3 generation fostering continuous convection within the anode. The high Peclet number suggests that the convection is the primary transport mechanism in the anode. The limited Sb2O3 reduction results in its accumulation in the upper layer, diminishing the effective reaction area and leading to a rapid decline in discharge voltage. However, the ionic conductivity of Sb2O3 at the Sb/Sb2O3 interface can facilitate approximately 10–20% of the reactions, marginally mitigating the increase in voltage loss. To offset Sb2O3 accumulation’s impact on the electrochemical reactions, a horizontal tubular LAA-SOFC is designed and constructed, which can effectively sustain the discharge voltage across a broad Sb2O3 fraction range of 0–85%.