Electric Encyclopedia — Types and Features of Air Batteries

With the global shift in energy structures and the accelerated process of electrification, air batteries have gradually attracted widespread attention as an emerging battery technology. The working principle of air batteries is to use oxygen from the air as the positive electrode material and metal as the negative electrode, with an electrolyte typically consisting of alkaline solutions or other liquid mediums. Air batteries offer high energy density and long service life, showing great potential, especially in electric vehicles and renewable energy storage. Depending on the negative electrode material used, air batteries can be classified into various types, including zinc-air, lithium-air, and aluminum-air batteries, which are the most widely researched and applied.

Zinc-Air Battery

The zinc-air battery is a type of primary battery that uses oxygen from the air as the positive electrode material, zinc as the negative electrode, and ammonium chloride or caustic alkali solution as the electrolyte. It operates similarly to a conventional primary battery but offers much higher energy density and lower manufacturing costs. This makes zinc-air batteries suitable for applications such as hearing aids, wireless sensors, and small electric tools. Despite its simple structure and relatively high energy density, zinc-air batteries face significant challenges in charging. The charging process is much slower than other types of batteries, and the zinc anode tends to oxidize during charging and discharging, causing it to lose effectiveness. As a result, zinc-air batteries generally need to be replaced or replenished with new zinc plates and electrolytes to restore their functionality. Nevertheless, zinc-air batteries are still an ideal choice for many fields due to their low cost and environmental friendliness.

Lithium-Air Battery

The lithium-air battery uses lithium metal as the negative electrode and oxygen from the air as the positive electrode material, with the electrolyte typically being an organic liquid solvent or solid electrolyte. Lithium-air batteries are regarded as a potential breakthrough in high-energy-density batteries, theoretically offering far greater energy density than conventional lithium-ion batteries. This makes them particularly promising for electric vehicles, where they could solve the issue of limited range. In theory, the positive electrode’s capacity is virtually unlimited since it can directly use oxygen from the air, significantly reducing the battery’s weight. Additionally, using metallic lithium as the negative electrode can further increase the battery’s energy density.

However, lithium-air batteries have not been widely adopted, mainly due to a fatal flaw. The lithium oxide (Li₂O₂) formed during the discharge process tends to accumulate on the positive electrode, blocking the contact between the electrolyte and the air, which eventually stops the discharge process. Despite ongoing research to address this issue, these challenges have prevented lithium-air batteries from reaching widespread commercialization.

Aluminum-Air Battery

The aluminum-air battery is a type of metal-air battery that uses aluminum as the negative electrode and oxygen from the air as the positive electrode material. Its advantages include high energy density, environmental friendliness, and the fact that aluminum is an abundant and inexpensive material. This gives aluminum-air batteries enormous potential for widespread use. Compared to other types of metal-air batteries, aluminum-air batteries also offer high efficiency and lower material costs, making them an attractive option for energy storage and electric vehicles.

One of the biggest advantages of aluminum-air batteries is that they are non-polluting, long-lasting, stable, and environmentally friendly. They can be adapted to various applications, from land-based vehicles to deep-sea exploration. Aluminum-air batteries are highly adaptable, making them suitable for use in military, aerospace, and other high-energy-consuming fields. However, aluminum-air batteries face challenges related to environmental influences, such as humidity, which can affect their performance. Improving the stability and durability of these batteries will remain a key area of research in the future.

Conclusion

Air batteries represent an emerging battery technology with high energy density, long service life, and environmental benefits. Zinc-air, lithium-air, and aluminum-air batteries each have their unique advantages and challenges. Although they still face technical bottlenecks, air batteries are expected to play an increasingly important role in future energy systems as researchers continue to address these challenges. With ongoing technological advancements and expanding application scenarios, air batteries are poised to become a key driver of the global energy revolution.