Australian researchers claim to have discovered the “holy grail” of solar PV recycling, by finding a way to extract silicon from discarded panels and repurpose it for use in the next big thing in low carbon energy generation and transport – lithium-ion batteries.

Material scientists Dr Md Mokhlesur Rahman and Prof Ying (Ian) Chen from Deakin University’s Institute for Frontier Materials say that just as silicon is the most important component of solar panels, it has represented the biggest hurdle to the effective recycling of used photovoltaic cells.

To this end, they have pioneered the investigation to nano-size recovered PV silicon, which they say can make high-energy anodes for lithium-ion batteries.

“Our discovery addresses several significant challenges currently facing industries dependent on batteries and energy storage heading into the future, Dr Rahman said.

“First, being such an exceptionally high value commodity with widespread applications we do not want any of this precious product wasted. Battery grade nano-silicon is highly expensive and retails for more than $44,000 per kilogram.

“Second, with the automotive industry set to be battery driven in the future, the push to find ways to increase battery capacity is growing.

“Part of the silicon repurposing process is to nano-size the battery grade silicon, leaving a nano-silicon which can store about 10 times more energy in the same space.

The team says preliminary investigations have validated the concept of disassembling silicon-based photovoltaic panels, and repurposing the existing silicon into nano-silicon for the battery industry, creating huge potential as an alternative source for the sector.

“Silicon cells are the most important component of a solar panel, transferring the sun’s energy into electrons,” Professor Chen said.

“They’re also a high-value material being a chemical element and far too precious to end up as waste, which is why this finding is significant.

“We can’t claim solar panels to be recyclable, in a circular economy sense, until scientists find a way to harvest and repurpose their most valuable components,” he said.

“Scientists have been looking for ways to repurpose the silicon for some time and we believe this to be the missing piece of the puzzle,” Dr Rahman added.

“It’s the holy-grail of repurposing – to take a product that would otherwise be waste, recycle it, and in the process make it even more valuable at the other end. ”

The project has been directly supported by Institute for Frontier Material’s Circular Economy Strategy Lead, Catherine McMahon, in collaboration with Deakin Research Innovations’ Senior Commercial Manager Andrew Rau and industry partner Delaminating Resources Melbourne.