French Scientists Recover 97% of Indium From Solar Panels

Scientists in France just solved a recycling puzzle that could help solar energy become even more sustainable.

Researchers at the French Alternative Energies and Atomic Energy Commission developed a new method to recover indium, a rare metal critical for high-efficiency solar panels. Using diluted oxalic acid (a compound similar to what's in rhubarb and spinach), they achieved a 97% recovery rate in a single step.

Indium powers the transparent conductive layers in heterojunction solar cells, some of the most efficient panels on the market today. As solar energy expands worldwide, recycling these materials will become essential for keeping production sustainable and costs down.

"Indium is a key material in heterojunction solar cells," explained lead researcher Romain Duwald. "Its recycling is essential for sustainable manufacturing and future waste management."

Traditional recycling methods rely on harsh industrial acids like hydrochloric or sulfuric acid, which create safety hazards and struggle to separate indium from tin. The French team's approach uses milder oxalic acid heated to 70 degrees Celsius for four hours, making the process safer for workers and facilities.

The technique works by dissolving the indium tin oxide layer from discarded panels, which also releases valuable silver grids intact. After filtering, the team converts recovered indium into high-purity oxide ready for reuse in new solar cells.

Testing confirmed the process removes indium cleanly while keeping silicon wafers and silver components separate for additional recovery. One chemical step accomplishes what previously required multiple hazardous treatments.

The Ripple Effect

This breakthrough arrives as solar installations surge globally, with panels from early projects beginning to reach end-of-life. Creating circular supply chains for rare materials like indium reduces mining pressure and strengthens energy independence.

The research team plans to expand their method to recycle indium from other electronics, potentially including smartphone screens and LED displays. Each advancement makes renewable energy more truly renewable by closing the loop on materials.

As solar technology improves, so does our ability to reuse what powers it.