Microwave Battery Recycling: Turning Waste Into a Strategic Resource

The transition to electric vehicles and renewable energy is often presented as a clean-energy success story. Yet behind the batteries powering this transformation lies a growing challenge: where will the raw materials come from, and what happens when millions of batteries reach the end of their lives?

These questions are at the heart of the work of Professor Elza Bontempi, a leading researcher at the University of Brescia in Italy. During a recent lecture on microwave thermal approaches for battery recycling, Bontempi outlined a novel technology that could help recover valuable materials from spent lithium-ion batteries while using less energy and fewer chemicals than conventional methods.

In a follow-up interview, she spoke about her motivation, the obstacles facing recycling technologies, and why she believes recovering materials from waste will be essential for a sustainable future.

Why battery recycling matters more than ever

The rapid growth of electric mobility is creating an unprecedented demand for critical raw materials such as lithium, cobalt, nickel and manganese. These elements are essential components of lithium-ion batteries, but obtaining them through mining can be resource-intensive and environmentally damaging.

During her lecture, Bontempi highlighted the scale of the challenge. Europe is expected to generate around eight million tonnes of waste batteries per year by 2050. At the same time, global supply chains for critical materials remain vulnerable to geopolitical tensions and resource limitations.

For Bontempi, recycling is not simply about waste management. It is about rethinking how society uses resources.

“My work is concerning the recovery of waste,” she explained. “In particular, I have devoted my research activity in the last years to critical raw materials, mainly metals but also graphite and also some material that are based on biological waste.”

The goal, she says, is to keep valuable materials circulating within the economy rather than continually extracting new resources from the Earth.

“I think that we have the possibility to recover some material and then to increase the sustainability of using resources,” she said. “The idea is to push the world toward a more sustainable future and reuse material because materials are not infinite.”

A new approach: Using microwaves to recover valuable metals

Traditional battery recycling generally relies on either pyrometallurgical or hydrometallurgical processes. Pyrometallurgy uses very high temperatures to recover metals, while hydrometallurgy often requires large quantities of aggressive chemicals.

Bontempi's team has been developing an alternative based on microwave-assisted carbothermic treatment. The process targets so-called “black mass” – the mixture of valuable battery materials that remains after batteries are dismantled and processed.

Instead of heating the entire system conventionally, microwaves selectively heat the materials, promoting reactions that help separate and recover critical elements.

The results presented during the lecture were striking. Experiments demonstrated recovery rates exceeding 95% for lithium, cobalt and manganese from mixed lithium-ion battery waste. The technology also appears highly adaptable, making it suitable for different battery chemistries and future battery designs.

Perhaps even more impressive is the potential reduction in energy consumption. Bontempi presented results from a newly patented microwave system capable of reaching temperatures of around 600°C in just 90 seconds using 300 watts of power. Conventional systems can require more than ten minutes and substantially higher power levels to achieve similar temperatures.

The technology aligns closely with the principles of the circular economy, an area where Bontempi has built an international reputation. Rather than viewing end-of-life batteries as waste, the process treats them as a source of secondary raw materials that can be fed back into manufacturing.

The hidden challenge: Regulation and technology transfer

While scientific breakthroughs often attract headlines, Bontempi believes some of the greatest barriers are not technical at all.

Asked about the biggest challenges she has faced in her career, she pointed to difficulties surrounding waste regulation and technology deployment.

“Some challenges are related to the waste,” she said. “There are some limitations about normative and legislation.”

One major issue is that once a material is legally classified as waste, transforming it into something that can be reused commercially becomes complicated.

“After the recovery, it's not so simple to try to reuse it,” she explained. “We have to face some normative constraints that don't facilitate the transfer of technology from the laboratory to the real world.”

This highlights a common problem in sustainability research. Developing a successful process in the laboratory is only the first step. Scaling that process, meeting regulations and integrating it into industrial supply chains can take many years.

For researchers working on circular economy technologies, policy frameworks can be just as important as scientific innovation.

Building a more sustainable future

Ultimately, Bontempi hopes her work will influence both industry and public attitudes toward resource use.

“I hope that in the near future it will be possible to increase the sustainability of the use of some devices, for example batteries,” she said.

She also sees opportunities to create entirely new materials from recovered battery components, reducing the need for virgin resources while supporting next-generation energy technologies.

“I hope that also it will be possible to get into people the idea that recycling is the best way to proceed for the next generation’s future.”

That message is particularly relevant as governments around the world invest heavily in electrification. Electric vehicles may help reduce carbon emissions, but ensuring their sustainability requires the full life cycle of battery materials to be addressed.

By recovering valuable metals rather than discarding them, recycling can help reduce environmental impacts, strengthen supply chains and lessen dependence on mining.

From laboratory innovation to real-world impact

Bontempi's research has already generated multiple patents and international recognition. Yet she remains focused on what happens next.

“We’ve had some good research results and the possibility to propose some patents,” she said.

The real test, however, is whether those innovations can make the leap from academic papers to commercial reality.

“I really hope that it will be possible to transfer to the real world some technology innovations,” she said. “It's very difficult to try to push research activities in the market.”

Her ambition is clear: to see these technologies deployed at industrial scale where they can have a measurable environmental impact.

As the world races toward an electrified future, battery recycling is becoming more than a waste-management issue. It is increasingly a question of resource security, sustainability and economic resilience. Through innovations such as microwave-assisted recycling, researchers like Elza Bontempi are helping to show that yesterday's battery waste could become tomorrow's strategic resource.

About the interviewee

Elza Bontempi earned her PhD in materials for engineering in 2001. Since 2011, she has been a full professor of fundamental chemistry for technologies at the University of Brescia (Italy).

She is an interdisciplinary researcher with recognised expertise in the circular economy, particularly in the development of sustainable materials and eco-materials. Her research focuses on sustainability-driven innovation, including alternatives to waste landfilling, strategic environmental management and the recovery of secondary raw materials. A major part of her work is dedicated to developing novel technologies for the recovery of critical raw materials, an area in which she holds several patents.

Professor Bontempi has received numerous prestigious awards for her pioneering contributions, especially in critical raw material recovery. These include the Innovation & Technology (EIT Raw Materials) International Prize “SusCritMOOC Business Idea Competition on Critical Raw Materials” and the WE Award – Women Excellence 2024 from Il Sole 24 Ore and the Financial Times. She has authored more than 350 publications indexed in Scopus and holds 10 patents, some of which have been successfully transferred to industry. Her research has also been featured by Science for Environment Policy, the information service of the European Commission’s Directorate-General for Environment.

She is ranked among the top European researchers in recycling innovations for lithium-ion battery sustainability, according to SciVal.

By Dr Karen Steward