Fact Check about the Three Foremost Types of Metal-air Batteries

What are Metal-air Batteries?

Metal-air batteries belong to secondary and primary type of cells in which the positive electrode is distinctively covered with carbon and precious metals that react with oxygen. The second electrode consists of metals such as aluminum, zinc, lithium, or magnesium. Furthermore, among the metal-air cells, the lithium-air battery possesses an exclusive feature that its energy is 100 times less as compared to that of diesel fuel. Due to this aspect, one can easily drive for 500 km with a 50 kg battery pack in a single charge.

What are the Three Prominent Types of Metal-Air Batteries?
The metal-air batteries are classified into varied types, based on their function and working. 

• Iron-Air Battery:
  
  The iron-air battery links the negative metallic electrode of low redox potential to the positive electrode. The basic parts of the iron-air battery are air positive electrode, iron negative electrode, and alkaline electrolyte. Apart from this, the theoretical voltage for this battery is based on oxygen reduction at the positive electrode and Fe /Fe (0) and Fe /Fe redox reaction at the negative terminal.
  Even though the iron-air battery encompasses charge and discharge aspects along with excessive electrode material, this battery is minor in energy expulsion as compared to the aluminum-air battery or zinc-air battery. This is so because the expected working voltage and expected capacity of the iron-air battery is lower than that of aluminum or zinc.  

• Lithium-Air Battery:
  
  The lithium-air battery comprises 5000 to 11,000 Wh Kg-1 specific energy density that highly depends on the character of the reacted products and electrolytes. As lithium metal reacts swiftly with water, the overall generation of energy from the lithium-air battery is remarkable than the other batteries like the zinc-air battery. In case of zinc-air cell, the anode terminal comprises concentrated aqueous potassium hydroxide electrolyte. Moreover, in the zinc-air cell, the electrolytes act as an ionic medium and reduce corrosion caused by oxygen and water. 
  Inside the lithium-air battery, the electrolyte maybe non-aqueous or aqueous and the cathode encompasses the product of cell discharge that also consists of gas diffusion electrodes (GDE). Moreover, aqueous lithium-air cell is considered superior over the zinc-air battery due to its high specific energy, open-circuit potential, and chemical isolation from the anode terminal due to which neutral, basic, or acidic electrolytes are utilized in lithium-air cell. 
  Beyond this, once the metal-air cells are activated, they undergo corrosion due to oxygen and water. Moreover, another issue encountered by lithium-air battery is the process of carbonation in which the atmospheric carbon dioxide reacts with potassium hydroxide and results in the formation of potassium carbonate. Similarly, in the lithium-air design, the lithium metal is isolated at anode terminal and averts self-discharge reaction with the oxygen element and permits the usage of acidic or neutral electrolyte that isn’t susceptible to carbonation process.

• Zinc-Air Battery
  
  The zinc–air batteries and zinc–air fuel cells are a type of metal–air batteries that are powered by oxidizing zinc metal with oxygen. These batteries are inexpensive to develop and consist of extreme energy densities. Sizes of zinc-air batteries range from tiny button cells utilized for hearing aids to large batteries that are mostly used for grid-scale energy storage and electric vehicle propulsion. 
  At the time of discharge, a distinctive quantity of zinc particles helps in developing a permeable anode that is often saturated with an electrolyte. Furthermore, oxygen reacts at the cathode terminal and results in the formation of hydroxyl ions that transfer into zinc paste to form zincate compound, thus releasing electrons to the cathode end. Furthermore, zincate transforms into zinc oxide and the water acts like an electrolyte. Hydroxyl and water from the anode side are recovered at the cathode terminal, so that the water isn’t exhausted. 
  
  Future Scope of Metal-Air Battery Market:
  
  According to a report published by Research Dive, the global metal-air battery market is estimated to enhance at a CAGR of 15.0% during 2020-2027 timeframe. In the present Covid-19 situation, the metal-air battery market is facing a downfall due to the lockdown that has disrupted the supply chains of batteries. Since China announced a lockdown before other countries the market fell further as China is considered as the leading manufacturer of metal-air batteries. Apart from this, this market is estimated to upsurge in the post pandemic period. 

About the Author(s)

Princy A. J

Princy holds a bachelor’s degree in Civil Engineering from the prestigious Tamil Nadu Dr. M.G.R. University at Chennai, India. After a successful academic record, she pursued her passion for writing. A thorough professional and enthusiastic writer, she enjoys writing on various categories and advancements in the global industries. She plays an instrumental role in writing about current updates, news, blogs, and trends.