My watch list  

Recycling old batteries into solar cells

Proposal could divert a dangerous waste stream while producing low-cost photovoltaics


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.

Amazingly, because the perovskite photovoltaic material takes the form of a thin film just half a micrometer thick, the team's analysis shows that the lead from a single carbatterycould produce enough solar panels to provide power for 30 households.

As an added advantage, the production of perovskite solar cells is a relatively simple and benign process. "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, Belcher says.

Those factors will help to make it "easy to get to large scale cheaply," Chen adds.

Battery pileup ahead

One motivation for using the lead in old car batteries is that batterytechnology is undergoing rapid change, with new, more efficient types, such as lithium-ion batteries, swiftly taking over the market. "Once the batterytechnology evolves, over 200 million lead-acid batteries will potentially be retired in the United States, and that could cause a lot of environmental issues," Belcher says.

Today, she says, 90 percent of the lead recovered from the recycling of old batteries is used to produce new batteries, but over time the market for new lead-acid batteries is likely to decline, potentially leaving a large stockpile of lead with no obvious application.

In a finished solar panel, the lead-containing layer would be fully encapsulated by other materials, as many solar panels are today, limiting the risk of lead contamination of the environment. When the panels are eventually retired, the lead can simply be recycled into new solar panels.

"The process to encapsulate them will be the same as for polymer cells today," Chen says. "That technology can be easily translated."

"It is important that we consider the life cycles of the materials in large-scale energy systems," Hammond says. "And here we believe the sheer simplicity of the approach bodes well for its commercial implementation."

Old lead is as good as new

Belcher believes that the recycled perovskite solar cells will be embraced by other photovoltaics researchers, who can now fine-tune the technology for maximum efficiency. The team's work clearly demonstrates that lead recovered from old batteries is just as good for the production of perovskite solar cells as freshly produced metal.

Some companies are already gearing up for commercial production of perovskite photovoltaic panels, which could otherwise require new sources of lead. Since this could expose miners and smelters to toxic fumes, the introduction of recycling instead could provide immediate benefits, the team says.

Facts, background information, dossiers
More about MIT
  • News

    How to spawn an 'exceptional ring'

    The Dirac cone started as a concept in particle and high-energy physics and has recently became important in research in condensed matter physics and material science. It has since been found to describe aspects of graphene, a two dimensional form of carbon, suggesting the possibility of ap ... more

    Researchers pioneer use of capsules to save materials, streamline chemical reactions

    Chemists working in a variety of industries and fields typically go through a laborious process to measure and mix reagents for each reaction they perform. And many of the common reagents they use sit for months or years on shelves in laboratories, where they can react with oxygen and water ... more

    A small, modular, efficient fusion plant

    It's an old joke that many fusion scientists have grown tired of hearing: Practical nuclear fusion power plants are just 30 years away - and always will be. But now, finally, the joke may no longer be true: Advances in magnet technology have enabled researchers at MIT to propose a new desig ... more

Your browser is not current. Microsoft Internet Explorer 6.0 does not support some functions on Chemie.DE