Materials from discarded car batteries could be the starting point for fabricating long-lasting solar panels, according to research published by a team from Massachusetts Institute of Technology. [AM Belcher, Energy Environ Sci (2014) online; DOI: 10.1039/C4EE00965G]
Angela Belcher, Paula Hammond, Po-Yen Chen and their colleagues suggest that the relatively new and rapidly spreading interest in perovskites for solar energy conversion could be exploited in recycling lead from worn out car batteries to make organolead halide perovskite solar panels. Perovskite-based solar cells are almost on a par with commercial silicon-based photovoltaics but are not nearly as fragile nor difficult to fabricate. The added dimension of using a recycled material that would otherwise leach the poisonous metal into the environment, through landfill disposal of hundreds of millions of car batteries, makes them an even better choice for tough, new solar panels.
The team's perovskite photovoltaic is formed as a thin film a mere half a micrometer thick and so a single discarded car battery would yield enough lead to build solar panels to power thirty households. The film fabrication process has another advantage in that it is relatively simple and operates at low temperature in stark contrast to the complexity of silicon photovoltaic device manufacture. In a finished solar panel, the layer containing the lead perovskite material will be encapsulated and can itself be recycled at the end of the panel's useful life. “The process to encapsulate them will be the same as for polymer cells today,” Chen explains.
The team explains that their "recycled" perovskite films show the same material characteristics, crystallinity, morphology, optical absorption and photoluminescence properties as films made from commercially available materials as well as having identical photovoltaic performance and resistance of electron recombination. This, they suggest indicate the practical feasibility of recycling car batteries for lead-based photovoltaics. Of course, currently, lead from discarded batteries can be retrieved to make new lead-acid batteries, but as new vehicle technology emerges the market for that older technology will gradually decline leaving us with a lot of waste lead to manage. Additionally, given the interest in lead perovskite photovoltaic materials, there is the potential for new lead mining with all the health and environmental risks that entails.
“It is important that we consider the lifecycles of the materials in large-scale energy systems,” Hammond adds. “And here we believe the sheer simplicity of the approach bodes well for its commercial implementation.” Having demonstrated proof of principle, the next step is to fine tune the lead perovskite technology to boost efficiency still further.
David Bradley blogs at http://www.sciencebase.com and tweets @sciencebase, he is author of the popular science book "Deceived Wisdom".