This project presents a high-temperature magnesium-air batteryMagnesium-air batteries designed for zero-emission maritime energy storageEnergy storage. The system operates at 420–620 °C using a NaCl-KCl-MgCl2 eutectic electrolyte, with magnesium metal as the anode fuel and ambient air as the oxidant. A containerized design includes ceramic insulation, angled electrodes for gas management, and pathways for MgO removal. Experimental results demonstrate open-circuit voltages of up to 1.9 V. Thermodynamic and system-level modeling estimate a fixed hardware cost of $5–10/kWh, with further reductions anticipated through reuse and scaling. Key material challenges include salt purity, crystallization behavior, and electrode stability under thermal and reactive conditions. The integration of electrochemical performance, material chemistry, and scalable engineering supports the feasibility of magnesium-air batteriesMagnesium-air batteries for long-duration stationery and transport-scale energyEnergy applications. Ongoing research focuses on improving rechargeability, understanding oxide growth, and optimizing system lifetime to advance this technology toward commercialization.