MIT Turns Dead Car Batteries Into Clean Solar Energy

When a car battery calls it quits, it usually ends up at a service station that disposes of it responsibly, because it contains toxic lead.

A team of MIT researchers thought there might be something worth keeping, and now say they have successfully recycled materials from spent batteries to create long-lasting, clean-running solar panels.

Recent solar cell research has included the use of perovskite – its formal name is “organolead halide perovskite” – which has been tweaked to the point where its efficiency in turning solar energy into electricity is nearly competitive with conventional solar cells.

“It went from initial demonstrations to good efficiency in less than two years,” team member Angela M. Belcher, the W.M. Keck Professor of Energy at MIT, told MIT News. Already, perovskite-based photovoltaic cells have achieved power-conversion efficiency of more than 19 percent, which is close to that of many commercial silicon-based solar cells, whose efficiency is around 25 percent.

Until now there’s been one serious liability to using perovskite technology: It uses lead, whose extraction from ores can produce toxic residues. But converting used automotive batteries for use in photovoltaic cells can keep their toxins out of landfills and, simultaneously, produce electric power for decades after they were thought to have been rendered useless.

In their paper published in the journal Energy and Environmental Science, a team led by Belch and Paula T. Hammond explains that the perovskite photovoltaic material is formed into a thin film no thicker than a microcrometer – one millionth of a meter. The lead recycled from just one recycled car battery could be used to provide solar power to 30 households.

Producing perovskite solar cells is fairly simple and not hazardous. “It has the advantage of being a low-temperature process, and the number of steps is reduced” compared with the manufacture of conventional solar cells, according to Belcher.

Another member of the team, Po-Yen Chen, an MIT graduate student, adds that this simple process will help make it “easy to get to large scale cheaply.”

Recycling used car batteries isn’t a new idea, but until now, about 90 percent are recycled into new car batteries. But that practice will diminish and perhaps even die out as automakers opt for different batteries for their cars. Using lead batteries for solar panels will give them new life.

As for lead in the solar panels themselves, Chen says it would be encapsulated with protective coatings to prevent environmental contamination, just as conventional cells are protected. When the solar panels are retired, she says, their lead can again be recycled into new solar panels.

By Andy Tully of Oilprice.com