Generalized Algebraic Phenomenological Model for Parallel-Plate Bipolar Electrochemical Reactors

Abstract

Electrochemical reactors with bipolar electrodes are widely used in industry and laboratories due to their ease of assembly and electrical connection. Understanding the impact of leakage currents on reactor performance is crucial for design improvement. Previous studies have analyzed these devices using the Laplace equation and Tafel kinetics for a single bipolar electrode. A simplified analysis of a reactor with multiple bipolar electrodes was also conducted, neglecting the contribution of intermediate electrodes to the leakage current. Here, a simplified model to analyse the influence of leakage current on electrode current distribution in a reactor with n bipolar electrodes is developed. Multiple models to study current that flows perpendicular to the electrodes, finally becoming parasitic current, are proposed. Also, two reaction kinetics, Tafel and Butler-Volmer, are taken into account. Experimental data from reactors with one bipolar electrode considering Tafel-type kinetics, and with one and two bipolar electrodes considering primary current distribution, are compared with predictions obtained through the Laplace equation, and the models of this paper. Given the current importance of green hydrogen, this work sheds light on the implications of the study and design of electrochemical reactors used in its production.