Recycling old car batteries into solar cells
Science Daily
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.
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 car
battery could 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 battery technology is undergoing
rapid change, with new, more efficient types, such as lithium-ion batteries,
swiftly taking over the market.
"Once the battery technology 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.
Story Source:
The above story is
based on materials provided by Massachusetts Institute of Technology.
The original article was written by David Chandler. Note: Materials may be edited for
content and length.
Journal
Reference:
1.
Po-Yen Chen, Jifa
Qi, Matthew T. Klug, Xiangnan Dang, Paula T. Hammond, Angela Belcher. Environmentally-responsible
fabrication of efficient perovskite solar cells from recycled car batteries. Energy & Environmental Science,
2014; DOI: 10.1039/C4EE00965G
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APA
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Massachusetts Institute of
Technology. "Recycling old car batteries into solar cells: Environmental
twofer could recycle lead batteries to make solar cells." Science
Daily, 18 August 2014.
<www.sciencedaily.com/releases/2014/08/140818113428.htm>.
