Magnesium is a promising anode material for rechargeable batteries due to its high theoretical capacity (2205 mAh/g), low redox potential (-2.37 V vs. SHE), and abundance. However, the use of magnesium metal as an anode is hindered by several challenges, including the formation of a passivating layer on the electrode surface, high corrosion rate, and dendrite growth during cycling. To overcome these challenges, alternative materials have been explored as magnesium electrodes. Here are some of the alternatives:
Magnesium alloys: Alloying magnesium with other elements can improve its electrochemical performance by modifying the surface chemistry and microstructure of the electrode. Common alloying elements include aluminum, zinc, calcium, and rare-earth metals. These alloys can enhance the corrosion resistance, reduce the passivation layer formation, and improve the cycling stability of magnesium electrodes.
Magnesium-based composite materials: Composite materials consisting of magnesium and other conductive materials, such as carbon, graphene, and metal oxides, have also been investigated as magnesium electrodes. These composites can improve the electrical conductivity, mechanical strength, and electrochemical performance of magnesium electrodes.
Intermetallic compounds: Intermetallic compounds formed between magnesium and other metals, such as aluminum, zinc, and titanium, have been explored as magnesium electrodes. These intermetallic compounds can exhibit improved electrochemical properties compared to pure magnesium, including higher capacity, better cycling stability, and reduced corrosion.
Conversion-type materials: Conversion-type materials, such as metal oxides, sulfides, and nitrides, can be used as magnesium electrodes. These materials undergo reversible conversion reactions during cycling, involving the intercalation/deintercalation of magnesium ions and the conversion of the electrode material to different phases. Conversion-type electrodes can provide high capacity and good rate capability.
Organic materials: Organic materials, such as conjugated polymers and small organic molecules, have also been investigated as magnesium electrodes. These materials can exhibit reversible redox reactions and can provide high capacity and good cycling stability.
The choice of alternative materials for magnesium electrodes depends on the specific application and desired performance characteristics. Further research and development are needed to optimize the performance of these alternative materials and enable the practical use of magnesium batteries.
