Electrochemical characterization and discharge performance of AZ31, AZ61 and AZ91 alloys as anodes for seawater battery

The abundance, environmental friendliness and high energy density of magnesium makes it an attractive option for eco-friendly battery development. This research article explores the performance of commercial magnesium alloys AZ31, AZ61 AZ91 in seawater battery applications, with a focus on corrosion resistance, discharge efficiency and long-term stability. The study highlights the role of aluminium concentration in these alloys, with a specific emphasis on how variations in concentration impact the performance metrics such as corrosion susceptibility, hydrogen evolution and anode utilization. Increasing the aluminium concentration to around 6 wt % in AZ61 not only boosts discharge activation but also enables the formation of protective magnesium aluminide (Mg₁₇Al₁₂), which acts as a barrier, preventing the self-peeling of corrosion products and enhancing stability during prolonged discharge. AZ61 emerges as the optimal alloy, balancing corrosion resistance, discharge efficiency, high anode utilization factor and long-term stability in highly corrosive seawater conditions. The results of electrochemical and discharge performance testing are supported by electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. The work offers a framework for future research that can boost the development on design of seawater battery with corrosion-resistant materials, high discharge efficiency and minimal adverse environmental impact.