Researchers develop method to recover antimony from solar cells

Researchers at Tallinn University of Technology are developing a chemical method to recover valuable antimony from end-of-life solar cells, ERR reported. Initial laboratory tests have achieved an antimony recovery yield of about 80 percent.

The project is being led by Jekaterina Sydorenko, a postdoctoral researcher at the Helmholtz Institute Erlangen-Nürnberg in Germany, in cooperation with scientists from Tallinn University of Technology.

The researchers are developing third-generation solar cells based on antimony compounds. They use antimony sulfide as the light-absorbing material because it can absorb light effectively in an extremely thin layer. Such inexpensive and flexible cells could eventually power low-energy Internet of Things devices, including motion sensors and thermostats, using indoor light.

Antimony compounds have long been used in flame retardants, batteries and the production of plastic bottles. Their use in solar glass is now also increasing rapidly. The solar industry’s share of global antimony consumption has risen from 1 percent to more than 26 percent, while the number of research studies using antimony sulfide in solar cells has also grown sharply.

Once these solar cells reach the market in large numbers, they will eventually become electronic waste unless they are recycled. Without recovery, valuable antimony could be sent to landfill instead of being reused.

Known global antimony reserves total 1.8 million tonnes, making it one of the fastest-depleting metals in the world. The global recycling rate remains low at 8.5 percent. Antimony supplies are also concentrated among a small number of countries, with China and Russia largely determining its availability on the world market.

Sydorenko’s research aims to develop chemical methods for dismantling end-of-life solar cells and separating antimony at a purity high enough for reuse. The researchers are developing the recycling methods alongside the new solar cells rather than waiting until the technology reaches the market.