Clean energy push: IISc's breakthrough low-cost zinc-air tech offers metal-free, low-emission alternative

In a discovery that could reshape energy storage and industrial pollution control, researchers from the Indian Institute of Science (IISc) have unveiled a breakthrough that turns zinc-air battery technology into a tool for cleaner hydrogen peroxide production.

Published in ACS Applied Materials & Interfaces, their method promises a low-cost, scalable solution that not only generates energy but also neutralises toxic dyes from the textile industry — offering a rare win for both sustainability and industry.

Zinc-air batteries have long been eyed as affordable, energy-dense alternatives to lithium-ion systems, operating with zinc metal as the anode and ambient air as the cathode.

Now, IISc scientists have reimagined the zinc-air battery, enabling it to generate hydrogen peroxide (H₂O₂) during its discharge cycle alongside storing power.

At the cathode, the battery triggers a reduction reaction, converting oxygen into hydrogen peroxide instead of water. Achieving this delicate chemical shift required the integration of a metal-free, chemically modified carbon catalyst into the system — a key innovation by the research team.

Unlike conventional H₂O₂ manufacturing methods, which are energy-intensive and depend on costly precious metals, this new approach offers a metal-free, low-emission alternative.

To demonstrate the system’s impact, researchers introduced toxic synthetic dyes — common textile industry pollutants — into the reaction. The hydrogen peroxide produced broke down the dyes, causing visible color changes and ultimately leading to complete degradation of color and toxicity.

Doctoral researcher Asutosh Behera, lead author of the study, emphasized the dual advantage: "The H₂O₂ generated will further decompose into various radicals (such as hydroxide and superoxide) — highly raw, reactive organic species — that will eventually degrade the textile dye," he explained.

Traditional hydrogen peroxide production depends on the anthraquinone process, which requires fossil fuels, emits carbon dioxide, and relies on rare metals like palladium or platinum. The IISc method circumvents these pitfalls entirely, leveraging abundant zinc and ambient oxygen to drive hydrogen peroxide production through battery chemistry.

Professor Aninda J Bhattacharyya, the study’s corresponding author, highlighted the broader impact: "This method is very sustainable, low-cost, and highly energy-efficient," he stated in the institute’s release.

This innovation sits at the crossroads of energy technology, green chemistry, and environmental remediation, offering a new class of multifunctional energy systems that can store electricity and perform chemical reactions simultaneously.

Such systems could find crucial roles in rural or off-grid areas, providing both power and wastewater treatment. With hydrogen peroxide also critical for medical sterilisation, wastewater purification and textile processing, the applications are wide-ranging.

It also reflects a growing trend of reengineering legacy battery chemistries — revisiting older technologies to extract secondary benefits once dismissed as inefficiencies, and turning yesterday’s problems into tomorrow’s solutions.