Scientists transform CO₂ into methane using spent batteries & aluminium foil

Battery waste poses a significant environmental threat, containing substances harmful to human health and ecosystems. However, these discarded batteries also contain valuable materials like nickel, which is essential for manufacturing new batteries. Thus, the development of efficient recycling methods is more urgent than ever.

Researchers at TU Wien (Vienna University of Technology) have devised an innovative process for extracting nickel from spent nickel-metal hydride batteries. But their breakthrough goes even further: By combining this recovered nickel with used aluminium foil, such as kitchen foil, they have created a nanocatalyst capable of converting CO₂ into valuable methane. This dual-purpose solution tackles the growing problem of battery waste and provides a climate-neutral fuel, offering a win-win for sustainability and clean energy.

Why battery recycling is essential for the environment and economy?

Prof. Günther Rupprechter, Head of the Research Project at the Institute of Materials Chemistry, TU Wien, explained that modern batteries, including nickel-metal hydride (Ni-MH) and lithium-ion types, are composed of various complex components, making their recycling and recovery processes technologically demanding.

Furthermore, if improperly disposed of, chemicals can leak, causing fires and pollution of the environment.

Recovering nickel from spent Ni-MH batteries holds significant economic value. In the EU, waste batteries and production scrap could supply approximately 16 per cent of the nickel required by 2030—enough to manufacture batteries for 1.3 to 2.4 million electric vehicles (EVs) annually.

However, the existing recycling capacity in the EU and the UK currently meets only a fraction—around one-tenth—of the projected demand for 2030. This underscores the urgent need for substantial investments in recycling infrastructure.

Recycling waste to capture CO₂ through upcycling

What is upcycling? The act of taking something no longer in use and giving it a second life and new function. In doing so, the finished product often becomes more practical, valuable, and beautiful than what it previously was.

The team successfully extracted nickel from used Ni-MH batteries and recovered alumina from discarded aluminium foil. They transformed these materials into high-performance nanocatalysts using environmentally friendly green chemistry methods.

Dr. Qaisar Maqbool, the study's first author, said, "Recycling is an important step, but upcycling nickel into catalysts capable of producing fuels can have an even greater impact."

"Our nanocatalyst consists of 92-96 per cent aluminium oxide and 4-8 per cent nickel, which is optimal for converting the greenhouse gas CO2 with hydrogen into methane," explains Günther Rupprechter.

In this process, neither high pressure nor high temperatures are required; the catalyst works at atmospheric pressure and can reach a temperature of 250°C.

Clean energy replaces greenhouse gases

This method offers a climate-neutral approach to converting CO₂ into a valuable fuel, with methane serving as a crucial energy source for various industries.

Prof. Günther Rupprechter emphasised that the team's next objective is to investigate how this process can be scaled for real-world technological applications. They believe this innovation has the potential to revolutionise sustainable fuel production, presenting a viable solution to the climate crisis while addressing a significant waste management challenge.

Dr Qaisar Maqbool explained the importance of closing the sustainability loop by reusing spent catalysts as their original precursors. This approach minimises waste and ensures an environmentally friendly process.

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