https://www.eenewseurope.com/en/recycling-solar-panels-for-ev-batteries/

Recycling solar panels for EV batteries
Technology News | September 11, 2023
By Nick Flaherty
MATERIALS & PROCESSES

Researchers in Singapore have developed an efficientmethod of recovering high-purity silicon from expired solar
panels to produce lithium-ion batteries.
The team at Nanyang Technological University (NTU)
used phosphoric acid, a substance commonly used in the foodand drink industry, as a single reagent rather than using several

different chemicals for recycling solar panels. This also has ahigher recovery rate and purity than today’s silicon recoverytechnologies.
High-purity silicon makes up the majority of solar cells, yet they
are typically discarded at the end of their operational lifespanafter 25 to 30 years. It is challenging to separate the silicon fromother solar cell components such as aluminum, copper, silver,lead, and plastic. Moreover, recycled silicon has impurities anddefects, making it unsuitable for other silicon-based technologies.
Existing methods to recover high-purity silicon are energyintensive and involve highly toxic chemicals, making them
expensive and limiting their widespread adoption amongrecyclers.
“Our approach to silicon recovery is both efficient and effective.
We do not have to use multiple chemicals, reducing the timespent on post-treatment of the chemical wastes. At the sametime, we achieved a high recovery rate of pure silicon comparable
to those produced by energy-intensive extraction techniques,”
said Nripan Mathews, Associate Professor Nripan Mathews,
Provost’s Chair in Materials Science and Engineering and Cluster
Director of the Energy Research Institute at NTU (ERI@N).
The 30 year lifespan of solar panels means that 78 million tons ofsolar panels are due to expire by 2050. The NTU research teambelieves their silicon recovery method can potentially solve thegrowing problem of solar panel waste by keeping resources in aloop.
•••

Standard needed for solar panel recycling
French deal for recycling solar panels
Enel shows progress on Europe’s largest solar panel plant

The NTU approach involves first soaking the expired solar cell in
hot diluted phosphoric acid for 30 minutes to remove metals(aluminium and silver) from their surfaces. This process isrepeated using fresh phosphoric acid to ensure complete removal

of the metals, resulting in pure silicon wafer at the end of another30 minutes.
The NTU Singapore researchers used the silicon from the recycled
solar panels in a lithium-ion battery anode and tested it forefficiency. Results showed that it performed similarly to new,commercially bought silicon. Spectroscopic analyses showed thesample achieved a recovery rate of 98.9 percent with a purity of
99.2 percent, comparable to silicon recovered through currently
available methods.
When the recovered silicon was upcycled into a lithium-ionbattery anode and tested for efficiency, it performed similarly tonew, commercially bought silicon.
“The comparable performance between our upcycled siliconbased lithium-ion battery and the newly purchased ones provesthat the NTU approach is feasible. We envision our faster andcheaper silicon recovery method to be a positive boost for thedevelopment of EV batteries. Aside from EVs, there are also
potential applications such as thermoelectric devices,” said Dr.
Sim Ying, Research Fellow, Energy Research Institute at NTU.
www.ntu.sg