Modeling and simulation of discharge behavior of Mg-H2O seawater battery

Abstract

Seawater based metal batteries are emerging as a viable battery technology with the potential to replace lithium-ion batteries, particularly for marine applications. These battery systems use naturally abundant seawater as the electrolyte, offering economic and environmental benefits. In the present work, a two-dimensional model is developed to predict the discharge behaviour of magnesium (Mg) seawater reduction batteries. A system of governing equations for Mg-based seawater batteries is presented based on a single-domain approach. By coupling electrochemical kinetics and mass transport within the cell, the model predicts the effect of current density and electrode area on the discharge potential. The simulated discharge curves are validated by fabricating a simple Mg/H2O battery system using pure Mg/Mg alloy (AZ61) as the anode, carbon cloth as the cathode and natural seawater as the electrolyte. The experimental discharge curves are in good agreement with the model predictions.