Zinc air batteries are the electro-chemical batteries powered by oxidizing zinc with oxygen from the air. These batteries possess high energy densities and are very cheap to produce. They are used in many devices including hearing aids,film cameras,electric vehicles etc. In future, the battery may be deployed as a utility-scale energy storage system.
In view of the batteries increasing usage, Stanford University scientists have developed an advanced zinc-air battery that could pave the way for the development of a inexpensive alternative to the traditional lithium-ion batteries that are widely used in many electronic devices today.
The research study results printed in the online edition of the journal Nature Communications stated that a zinc-air battery with higher catalyst activity and long lasting nature has been created which are much efficient than the similar batteries made with the most expensive platinum and iridium catalysts.
Beacause zinc metal is abundant and inexpensive, zinc batteries are attractive and the non-flammable nature of aqueous electrolytes makes the batteries very safe to use and operate. They produce electricity leaving zinc oxide as a byproduct of the reaction. Oxygen and zinc metal are regenerated when the chemical process is conversed during recharging.
To accelerate the oxygen-reduction reaction during discharge as well as evolute oxygen during recharge, active and durable electrocatalysts are required which are very slow in the zinc-air batteries.
The research team has developed a number of electrocatalysts with high-performance made up of non-precious metal oxide or nano-crystals hybridized with carbon nano-tubes. These catalysts generated high catalytic activity and durability in alkaline electrolytes than catalysts made with platinum and other precious metals.
These catalysts increased the performance of both non-rechargeable and rechargeable zinc air batteries. A mixture of cobalt-oxide hybrid air catalyst for oxygen reduction and a nickel-iron hydroxide hybrid air catalyst for oxygen evolution proved to be effective and gave a high-energy efficiency for a zinc-air battery. The high energy density is more than twice that of lithium-ion technology.
This unique battery also showed good reversibility and stability for long charge and discharge cycles over several days. It can be used widely as the metal-air batteries have relatively high energy densities than traditional aqueous batteries or lithium-ion batteries.
Thus, this research work could be an important milestone in the development of zinc-air batteries which can be used for various purposes.
The demand for high-performance, inexpensive and safe batteries for portable electronics, electric vehicles and other energy storage applications is increasing day-by-day and the usage of metal-air batteries like zinc-air is the best possible solution to reach the demand.