In this demonstration video, an old car battery is disconnected, rinsed and disassembled. The lead iodide collected from the battery's interior is heated for five hours, dissolved in acid, mixed with a potassium solution and purified.
The resulting material is spun into thin sheets that are half a micrometer thick and are coated with lead iodide perovskite.
The material harvested from one old lead-acid battery would suffice to assemble 709 sq. meter panels, and potentially power just over 30 homes in Las Vegas.
According to the Battery Council International, over 98 percent of all battery lead is currently recycled. Old batteries are broken apart in a hammer mill, which breaks the battery into pieces. The components are poured into a vat where the materials are separated by liquids which allow the polypropylene plastic shell pieces to float to the top. The plastic is cleaned, melted and extruded into pellets that are remanufactured into battery cases.
Touted as a closed-loop life cycle, lead acid battery recyclers claim to use between 60 and 80 percent recycled lead and plastic in new batteries.
The MIT researcher's solar cells also use recycled lead from car batteries. Landfill disposal of old lead-acid batteries is illegal due to the inherent toxicity of the contents, but with such a relatively efficient recycling system for the batteries, is there a need to re-appropriate the material?
According to Belcher, lead acid batteries are an ideal feedstock into their system because battery technology is changing quickly. New and better batteries made from lithium and lithium-ion are quickly displacing the less efficient ones made with lead. Once the market shift is complete, about 200 million lead-acid batteries will need a new home or use in the U.S. alone.
Cheap solar panels could be the solution to that potentially hazardous situation. The cells are encapsulated, preventing any lead from re-entering any ecosystem.
Other benefits to creating renewable energy from the material is that it is low-temperature, requires fewer steps than current solar panels to produce, and is a less energy-intensive product to create.
Dr. Hammond stressed that the life cycles of the materials in large-scale energy systems need to be considered.
Read more about the system in Energy and Environmental Science.