Understanding Direct Borohydride – Hydrogen Peroxide Fuel Cell Performance with a Calibrated Numerical Model

Abstract

A numerical model is developed for a hydrogen peroxide – direct borohydride fuel cell (H2O2-DBFC) to provide insight into cell processes which are obscured in experiments by the complexity of electrode reactions and transport in the reactant flow channels. In the model, transport is modeled using a 2D finite volume approach. Multi-step electrode reactions, including competing parasitic reactions, are represented by global rate expressions, with parameters calibrated to single-cell experiments. The results are calibrated to a H2O2-DBFC in which fuel (1-50 mM NaBH4 / 2 M NaOH) is oxidized at a Au anode and oxidizer (10-40 mM H2O2 / 1 M H2SO4) is reduced at a Pd:Ir cathode. This modeling approach provides critical insight into the rate-limiting processes at different operating conditions of a H2O2-DBFC.