Magnesium batteries represent a promising alternative to lithium-ion systems due to magnesium's high theoretical volumetric capacity, abundance, and improved safety characteristics. However, several challenges must be addressed to realize their commercial potential. Key research avenues focus on developing compatible electrolytes, stable cathodes, and understanding interfacial phenomena to overcome kinetic limitations and cycling instability.

Electrolyte development remains a critical hurdle for magnesium batteries. Conventional electrolytes used in lithium systems are incompatible with magnesium due to passivation layer formation on the anode surface, which blocks ion transport. Recent advances in non-nucleophilic electrolytes, such as magnesium aluminum chloride complex (MACC) and magnesium boron-based systems, have shown improved oxidative stability and Coulombic efficiency exceeding 95%. Chloride-free electrolytes based on weakly coordinating anions demonstrate enhanced compatibility with high-voltage cathodes, enabling operation above 3.0 V versus Mg/Mg2+. Research into solid-state magnesium electrolytes, including magnesium thiophosphates and borohydrides, has shown ionic conductivities approaching 10^-3 S/cm at room temperature, though interfacial resistance remains a challenge.

Cathode materials require innovation to achieve practical energy densities. Intercalation-type cathodes face limitations due to strong electrostatic interactions between Mg2+ ions and host lattices, leading to slow diffusion kinetics. Chevrel-phase Mo6S8 remains a benchmark material with reversible capacity around 100 mAh/g, but its low voltage plateau near 1.1 V limits energy density. Transition metal oxides, particularly layered structures like V2O5 and MnO2, have demonstrated improved capacities up to 250 mAh/g when combined with nanostructuring and water-containing electrolytes. Conversion-type cathodes based on sulfur or selenium offer higher theoretical capacities but require solutions for polysulfide shuttling and volume expansion. Organic cathodes, such as quinone-based polymers, show promise with capacities exceeding 300 mAh/g and better compatibility with magnesium ions.

Anode interface engineering is essential for preventing passivation and dendrite formation. While magnesium metal itself is less prone to dendrites than lithium, uneven deposition can still occur at high current densities. Surface treatments using artificial SEI layers, such as magnesium fluoride or magnesium borate, have improved deposition uniformity. Alloy anodes, including Mg-Sn and Mg-Bi systems, demonstrate reduced overpotentials below 200 mV while maintaining capacities above 500 mAh/g. Research into three-dimensional current collectors with tailored pore structures has shown enhanced cycling stability at practical areal capacities above 3 mAh/cm2.

System architecture innovations address transport limitations in magnesium batteries. Dual-ion configurations that pair magnesium metal anodes with alternative charge carriers, such as anions or protons, can bypass magnesium ion diffusion limitations in cathodes. Hybrid systems combining magnesium with lithium or sodium ions in the electrolyte have demonstrated improved rate capability while maintaining magnesium's capacity benefits. Flow battery designs using magnesium deposition/dissolution at the anode and liquid-phase catholytes could overcome solid-state diffusion barriers.

Fundamental electrochemistry studies are needed to understand charge transfer mechanisms at magnesium interfaces. In-situ characterization techniques, including X-ray absorption spectroscopy and electrochemical quartz crystal microbalance measurements, have revealed details about solvation structures and interfacial reactions. First-principles calculations predict that certain crystal structures, such as spinel MgMn2O4, should enable faster magnesium diffusion if synthetic challenges can be overcome. Research into cooperative insertion mechanisms, where multiple ions participate in charge compensation, may provide pathways to overcome the high charge density limitations of Mg2+.

Manufacturing considerations for magnesium batteries differ from lithium systems due to material reactivity. Dry room processing may be necessary to prevent electrolyte decomposition during cell assembly. Electrode formulations require optimization to account for magnesium's larger ionic radius, with binder systems needing higher flexibility to accommodate volume changes. Current collector choices are limited by magnesium's reduction potential, with stainless steel or nickel foils showing better compatibility than aluminum.

Performance metrics for prototype magnesium batteries have reached energy densities of 250 Wh/kg at the cell level, with some laboratory demonstrations achieving 400 cycles at 80% capacity retention. Power density remains a challenge, typically below 500 W/kg, due to kinetic limitations at both electrodes. Temperature performance shows wider operational ranges than lithium-ion, with functional demonstrations from -30°C to 60°C using appropriate electrolyte formulations.

Environmental and economic analyses suggest magnesium batteries could achieve material costs below $50/kWh at scale, with mining and processing energy requirements approximately 30% lower than lithium equivalents. Recycling pathways appear favorable due to magnesium's relative ease of recovery through molten salt electrolysis or direct reuse approaches.

Technical challenges requiring continued research include improving electrolyte oxidative stability above 4.0 V, developing cathode materials that combine high voltage and capacity, and understanding long-term degradation mechanisms. Multiscale modeling efforts are needed to bridge atomic-scale interface phenomena with macroscopic cell performance. Standardization of testing protocols will enable better comparison between research results from different groups.

The path to commercialization will likely involve niche applications where magnesium's safety and cost advantages outweigh current performance limitations, such as grid storage or aerospace applications, before expanding to broader markets. Continued progress in materials chemistry and engineering solutions suggests that magnesium battery technology may reach practical viability within the next decade.