Researchers from the Institute for Frontier Materials (IFM) at Deakin University in Australia have successfully tested a novel method for removing silicon from used solar panels and turning it into a nanomaterial worth more than $45,000 per kilogram.
A major breakthrough
“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 lead researcher Mokhlesur Rahman in a statement. “We have developed a process that returns silicon collected from used cells to greater than 99 per cent 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 nano-silicon extracted from this process is then combined with graphite to create a novel kind of battery anode that has been shown to multiply the capacity of lithium-ion batteries by ten. “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.
The growth of solar power
Photovoltaic (PV) cells are the components of solar panels that convert sunlight into electrical energy. These cells, also called solar cells, are made of a semiconductor material. With silicon accounting for over 95% of the modules supplied today, this material is the most prevalent semiconductor in solar cells.
According to the International Energy Agency (IEA), solar PV generated a record 179 TWh more energy in 2021 than in the previous year, a 22% increase. In 2010, Solar PV generation amounted to just 32.2 TWh.
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Aside from solar cells, solar panels are made of other parts and materials, such as a metal frame and a glass sheet. The value of the recoverable raw materials from out-of-commission solar panels worldwide will total around $450 million by 2030, according to the International Renewable Energy Agency (IRENA). The recycling of solar panels can include the isolation of the glass from the silicon wafer and the isolation and purification of the silicon cells and metals such as copper, lead, silver, and tin.
According to the 2021 report “Solar Photovoltaic Module Recycling: A Survey of U.S. Policies and Initiatives” by the National Renewable Energy Laboratory (NREL) and the Electric Power Research Institute (EPRI), anecdotal information indicates that less than 10% of PV modules are being recycled in the United States.
“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 Professor Ying (Ian) Chen, Director of the ARC Research Hub for Safe and Reliable Energy, “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.”
Due to the lack of soil for the construction of PV plants, the Japanese company Kyocera has thought to build one on a water reservoir. This is the result.
