It’s great that manufacturers recover lead from discarded car batteries to use in new ones, since lead production from ores yields toxic residues. The problem is, when we shift from lead-acid to lithium-ion and other types of batteries (and we’re starting to), over 200 million old batteries could be retired in the US and cause serious environmental issues. Thankfully, a team of MIT researchers has discovered one way to recycle lead from car batteries, and the end product is something very, very useful: long-lasting solar cells. We’re talking about a new breed of solar cells in particular, one that uses a compound called perovskite, which needs lead to be manufactured.

This could be a classic win-win solution: A system proposed by researchers at MIT recycles materials from discarded car batteries — a potential source of lead pollution — into new, long-lasting solar panels that provide emissions-free power. The system is described in a paper in the journal Energy and Environmental Science, co-authored by professors Angela M. Belcher and Paula T. Hammond, graduate student Po-Yen Chen, and three others. It is based on a recent development in solar cells that makes use of a compound called perovskite — specifically, organolead halide perovskite — a technology that has rapidly progressed from initial experiments to a point where its efficiency is nearly competitive with that of other types of solar cells. “It went from initial demonstrations to good efficiency in less than two years,” says Belcher, the W.M. Keck Professor of Energy at MIT. 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. Initial descriptions of the perovskite technology identified its use of lead, whose production from raw ores can produce toxic residues, as a drawback. But by using recycled lead from old car batteries, the manufacturing process can instead be used to divert toxic material from landfills and reuse it in photovoltaic panels that could go on producing power for decades.