Scientists have developed a metal-free porous material that can deliver catalytic performance close to platinum, potentially lowering the cost of next-generation clean-energy technologies such as zinc-air batteries.
Zinc-air (Zn-air) batteries generate electricity through the oxygen reduction reaction (ORR), in which oxygen from the air reacts at the electrode. The efficiency of this reaction plays a critical role in determining battery performance.
Zn-air batteries are considered a promising option for next-generation energy storage because they use zinc, an abundant, relatively inexpensive and safe material, while drawing oxygen directly from the air instead of storing an active cathode material.
Compared with conventional lithium-ion batteries, Zn-air systems have the potential to offer higher theoretical energy density, lower material costs, improved safety and greater sustainability. However, challenges related to rechargeability, cycle life and ORR kinetics remain.
Efficient oxygen electrochemistry is also critical for hydrogen fuel cells. Many such clean-energy technologies currently rely on platinum as an ORR catalyst because of its high catalytic efficiency. However, platinum’s high cost, scarcity and limited availability remain significant barriers to large-scale deployment.
Researchers from the S.N. Bose National Centre for Basic Sciences (SNBNCBS), Kolkata, the Institute of Nano Science and Technology (INST), Mohali — both institutions under the Department of Science and Technology (DST) — and SRM University, Amaravati, have developed a metal-free organic porous material that could provide an alternative.
The material, named TTT-DHTD, was prepared using 2,4,6-tris(4-aminophenyl)-1,3,5-triazine (TTT) and 4,8-dioxo-4,8-dihydrobenzo[1,2-b:4,5-b’]dithiophene-2,6-dicarbaldehyde (DHTD) linkers. The findings were published in the journal Science Advances.
When used as an air-electrode catalyst in Zn-air batteries, TTT-DHTD performed nearly as well as platinum without using precious metals, according to the researchers.
Made entirely from abundant elements such as carbon, sulfur, nitrogen and hydrogen, the material forms an ultra-porous, honeycomb-like network that facilitates the conversion of oxygen into electricity.
Laboratory tests showed that the catalyst achieved about 96 per cent of the performance of commercial platinum catalysts while demonstrating high stability. It maintained its performance after 120 hours of continuous operation without the degradation or contamination that can affect conventional metal-based catalysts.
The research was led by Dr Pradip Pachfule of SNBNCBS, Prof Ramendra Sundar Dey of INST and Prof Ranjit Thapa of SRM University, Amaravati.
The researchers also used advanced computer simulations to investigate the material’s catalytic performance. The studies showed that its engineered molecular structure creates favourable sites for oxygen molecules to attach and react, facilitating efficient electricity generation.
The findings suggest that replacing platinum with inexpensive organic materials could reduce the cost of Zn-air cells and potentially support wider adoption in clean transportation, portable power systems and renewable-energy storage.
The study demonstrates how molecular design and computational modelling can enable earth-abundant materials to approach the performance of precious metals in key electrochemical reactions.
Researchers said the development could contribute to efforts to create more affordable, durable and sustainable energy-storage and fuel-cell technologies.
-PIB
