High-efficiency, low-cost solar cells can be made from recycled car batteries

recycled lead from car batteries
© Christine Daniloff/MIT

MIT researchers have developed a simple process for making perovskite solar cells with lead recovered from old car batteries.

In the quest for more affordable and efficient clean energy production, perovskite solar cells are a promising development, as they can be made from materials which are abundant and easily processed at low temperatures. And because the resulting cells can be thin, flexible, and lightweight, they may lend themselves to being installed on non-traditional solar surfaces, such as windows or building facades.

However, perovskite cells all use lead as a key ingredient, and to scale up production of these efficient solar components, additional mining and smelting of lead would be required, which adds to the environmental footprint of their manufacture. Researchers are working to find a non-lead substitute for perovskite solar cells, but so far, no alternative materials have proven to be as effective as lead is.

But now these perovskite solar cells are getting another potential eco-boost, as MIT researchers have found a way to produce them using recycled lead from discarded car batteries, which can lessen the impact of their production on the environment. According to the team behind the discovery, perovskite solar cells made with recycled lead work "just as well as those made with high-purity, commercially available starting materials," which means that recycling the lead from car batteries could help support the production of these next-generation cells, and could be an important bridge for perovskites until lead can be replaced by a less toxic but just as efficient material.

Here's how the MIT team made perovskite solar cells from recycled lead-acid car batteries:

This discovery may also prove to be an important element of dealing with obsolete car batteries in the near future, when lead-acid batteries will be eventually replaced by newer and more efficient versions, and existing lead batteries will need to be dealt with safely, economically, and in an environmentally sound manner. It also suggests that the process could have significant potential economic benefits, and could be a key element in scaling up production of perovskite solar cells.

"Assuming that the perovskite thin film is just half a micrometer thick, the researchers calculate that a single lead-acid car battery could supply enough lead for the fabrication of more than 700 square meters of perovskite solar cells. If the cells achieve 15 percent efficiency (a conservative assumption today), those solar cells would together provide enough electricity to power about 14 households in Cambridge, Massachusetts, or about 30 households in sunny Las Vegas, Nevada. Powering the whole United States would take about 12.2 million recycled car batteries, fabricated into 8,634 square kilometers of perovskite solar panels operating under conditions similar to those in Nevada." - MIT News

Before you start breaking open old car batteries and making your own solar cells, remember that while the process may be described as 'simple' when done by MIT researchers, it's not really appropriate for a home science project unless you've got the know-how, the skills, and the equipment to deal with the sulfuric acid and lead in the batteries without causing harm to yourself and others.

For the technical side of this research, see Environmentally responsible fabrication of efficient perovskite solar cells from recycled car batteries in the journal Energy & Environmental Science.

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