Using solar panel waste to build better batteries

By reclaiming one of the most valuable elements from end-of-life solar panels and reconfiguring it to build better batteries, researchers have developed a sustainable way to address two issues in the clean energy transition.

By 2035, more than 100,000 tonnes of end-of-life solar panels are estimated to enter Australia’s waste stream.

Scientists from Deakin University’s Institute for Frontier Materials (IFM) have tested a process to extract silicon from old solar panels and convert it into a nano material worth more than $45,000 per kilo.

The nano-silicon developed by the researchers can be mixed with graphite to develop a type of battery anode shown to increase lithium-ion battery capacity by a factor of 10.

Dr Md Mokhlesur Rahman, lead researcher, said the only way to address the issue of solar panel waste and develop a successful recycling program is for scientists to find a way to harvest and repurpose the panels’ most valuable components.

“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,” Rahman said.

The process his team has developed returns the silicon from used cells to about 99% purity within a day without the need for dangerous chemicals. It then takes the regular-sized purified silicon and reduces its size to nanoscale using a special ball-mining process, also without using dangerous 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,” Rahman said.

Nano-silicon is in high demand not just for battery materials but for the development of nano-fertilisers, new methods for carbon capture and on-demand hydrogen gas generation.

By recycling solar panels, the researchers have found a way to make this material more accessible. Their technique could generate an estimated US$15bn in material recovery if extrapolated to the 78 million tonnes of solar panel waste that is expected to be generated globally by 2050.

The process comes from years of research from a team led by Alfred Deakin Professor Ying (Ian) Chen, Director of the ARC Research Hub for Safe and Reliable Energy, based at IFM in Geelong. The work has been supported with funding from ARC and Sustainability Victoria. The team is now talking with industry about plans to upscale the process.