“Greener and cheaper:” Deakin Uni extracts silicon from solar panels to make batteries

In a landmark discovery that helps to solve two long-term challenges in the clean energy transition, researchers at Australia’s Deakin University have developed a new process to extract silicon from solar panels for use in building better batteries.

Scientists from Deakin University’s Institute for Frontier Materials (IFM) say they have successfully developed a new process that safely and effectively extracts silicon from end-of-life solar panels. The process is able to then convert the silicon into a nano material reportedly worth over $45,000 per kilo.

The nano material can then be mixed with graphite to develop a new type of battery anode which has been shown to increase lithium-ion battery capacity by up to a factor of 10.

The discovery could serve to be not only a lucrative opportunity, but could hopefully address the more than 100,000 tonnes of end-of-life solar panels currently estimated to enter Australia’s waste stream by 2035.

“Solar panel cells are fabricated using high-value silicon, but this material cannot be re-used without purification, as it becomes highly contaminated over the 25 to 30 years of the panel’s life,” said Dr Md Mokhlesur Rahman, the lead researcher on the project.

“We have developed a process that returns silicon collected from used cells to greater than 99% purity, within a day and without the need for dangerous chemicals. This thermal and chemical process is far greener, cheaper, and more efficient than any other technique currently on the market.”

The purified silicon is then reduced down to nanoscale using a special ball-milling process which similarly has no need for toxic chemicals.

“We are using that nano-silicon to develop low-cost battery materials that will help deliver the higher performing, longer lasting, affordable battery technology critically needed to drive Australia’s clean energy transition,” Dr Rahman said.

The high price of nano-silicon is due in large part to the huge demand. Used not just in new battery materials, but also in the development of nano-fertilisers, carbon capture methods, and on-demand hydrogen gas generation.

It is estimated that this new technique could generate $US15 billion in material recovery – if extrapolated to the 78 million tonnes of solar panel waste expected to be generated globally by 2050.

The newly developed process is the result of years of research by a team led by Alfred Deakin Professor Ying (Ian) Chen, Director of the ARC Research Hub for Safe and Reliable Energy, which is based at IFM in Geelong.

“This Deakin developed technology – including purification, nano-silicon production and integration into new battery technology – is a giant leap forward in how we tackle the problem of solar panel waste,” said Chen.

“Silicon recovered from end-of-life solar panels can be a massive, sustainable source of nano-silicon to meet future demand for raw battery materials. Helping to power the homes, transport and communities of the future.”