Recently, two research fellows from Jawaharlal Nehru Centre for Advanced Scientific Research in Bengaluru won the silver award at KPIT Sparkle 2020 for designing the most efficient and eco-friendly rechargeable zinc-air batteries for electric vehicles. KPIT Sparkle is an innovation platform that allows the youth to make an impact in the field of automotive software and nurture talent for the evolving mobility ecosystem. Tarandeep Singh, one of the fellows, is a researcher at the Department of Chemistry and Physics Material Unit. He believes that zinc-air batteries are the future of tomorrow, "At a time when the fuel prices are increasing and global warming is on rise, the metal-air batteries, especially zinc-air batteries, have huge scope in the market. That's why we wanted to work on this product and we're planning to launch it in the market soon." We converse with him to know more about these batteries. Excerpts:
1. What is a rechargeable zinc-air battery?
Primary (non-rechargeable) zinc-air batteries have been in the market for a long time. To understand the rechargeable zinc-air batteries, it would be easier to first look at the chemistry behind it. During the discharging process of a zinc-air battery, oxygen reduction reaction takes place at the cathode. Till date, many electrocatalysts have been developed and have already been commercialised. But to recharge the battery electrically, a bi-functional cathode material is required that is active towards oxygen reduction reaction as well as oxygen evolution reaction. So, a battery with a bi-functional cathode material can be recharged upon the application on current. Apart from this, zinc-air batteries also have the capability of mechanical rechargeability. So, the battery can be charged similar to initial performance upon the addition of either zinc plates or replacement of aqueous electrolyte back into the system.
2. How it is different from other batteries used in electric vehicles? What led you to come up with this product? Zinc-air batteries are entirely different from the other batteries used in electric vehicles. They are a hybrid of traditional batteries and fuel cells. This uses air as the fuel to give out current. Apart from this, Zn-air batteries use zinc, an inexpensive metal, as anode, aqueous electrolytes and does not require any inert atmosphere for fabrication process. These are in sharp contrast to the present batteries used in e-vehicles which use lithium an electrode, organic electrolytes and requires inert atmosphere for fabrication. Apart from these reasons, Zn-air batteries have higher specific energy as compared to the present Li-ion batteries being used in EVs. The use of Li-ion battery technology increases the cost of the battery packs, thus increasing the overall cost of the vehicle. Apart from this, long charging time, inadequate charging facility and the absence of Li metal ores in India motivated us to come up with an alternate technology for EVs.
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3. What were the challenges you faced in developing this battery?
Zn-air batteries provide high capacity but lack on power capability, due to which it has not been commercialised till date. Electrical rechargeability is another issue that prevented its commercialisation for EVs. To challenge that, we developed an electrically and mechanically rechargeable Zn-air battery. Moreover, to address the power issue, we improved the design of the battery and lowered its internal resistance. With this, we were able to increase the power of the battery by approximately 2.5 folds.
4. How are these batteries going to help the environment?
Zn-air batteries do not use any organic electrolytes, which are not environment-friendly. Zn-air batteries use air as the fuel along with an aqueous electrolyte. Also, the products formed after the discharge of the battery are eco-friendly and can be recycled easily with already known methods.
5. When will you be filing for a copyright patent?
The process of filing for a copyright patent is ongoing and will be completed soon, so that the product can be launched in the market at the earliest.
