New Zinc-Air Battery Makes Power And Hydrogen Peroxide For Cleaning Wastewater

In an era where energy innovation and environmental sustainability are more critical than ever, researchers at the Indian Institute of Science (IISc) have struck gold—or rather, zinc. By reimagining the humble zinc-air battery, the team has crafted a versatile solution that addresses three pressing global concerns simultaneously: clean energy storage, eco-friendly chemical production, and wastewater remediation.

Lithium-ion batteries have long been the champions of energy storage, powering everything from phones to electric vehicles. But with their steep costs and limited scalability, especially for grid-level storage, alternatives are in high demand. This is where zinc-air batteries shine. Zinc, being cheap and readily available, serves as the anode, while the cathode draws in ambient air. When the battery is in use, oxygen at the cathode is reduced—ideally forming water or, in this breakthrough, hydrogen peroxide (H?O?).

What sets the IISc innovation apart is how it retools the chemistry to deliberately generate hydrogen peroxide instead of water. “The strategy here is to control the extent of the oxygen reduction reaction,” explained Prof. Aninda Bhattacharyya, who led the research at IISc’s Solid State and Structural Chemistry Unit (SSCU). “If you don’t control it at some level, it will just go and form water.”

The team employed a metal-free carbon-based catalyst to guide the reaction in the desired direction. This makes the setup more affordable than traditional methods, which often rely on precious metals and energy-intensive processes. Carbon catalysts, enhanced with oxygen-rich functional groups, help ensure the reaction results in H?O? rather than H?O.

But detecting a colorless compound like hydrogen peroxide requires creativity. The researchers added textile dye to the mix, which changes color in the presence of H?O?. This clever visual cue served as proof of production. Moreover, H?O? goes a step further: it decomposes into highly reactive radicals that break down the dye, a process with direct applications in wastewater treatment.

“The H?O? generated will further decompose into various radicals (such as hydroxide and superoxide) – highly raw, reactive organic species – that will eventually degrade the textile dye,” noted Asutosh Behera, a PhD student who contributed to the research.

This means the battery doesn’t just store and release power—it actively purifies water contaminated by textile dyes, offering a sustainable solution for one of the most polluting industries globally. And all it needs to function is zinc and air. “You don’t have to do other things. You have a battery, and you run it,” Bhattacharyya summed up, underscoring the simplicity and elegance of the design.