Environmentally Responsible Fabrication of Efficient Perovskite Solar Cells from Recycled Car Batteries

Environmentally Responsible Fabrication of Efficient Perovskite Solar Cells

from Recycled Car Batteries

Po-Yen Chen^1,2*, Paula T. Hammond¹, Angela M. Belcher³

¹Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139

²School of Engineering, Brown University, Providence, RI 02912

³Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139

Email: pychen@mit.edu

 

            Organolead halide perovskite solar cells (PSCs) show great promise as a new large-scale and cost-competitive photovoltaic technology. Power conversion efficiencies over 15% to over 20% have been achieved within 18 to 36 months of development, and thus perovskite materials have attracted great attention in photovoltaic research. However, the manufacture of PSCs raises environmental concerns regarding the over-production of raw lead ore, which has harmful health and ecological effects. In this study, we have demonstrated an environmentally responsible synthetic pathway to reuse car batteries for the fabrication of efficient PSCs (Figure 1). Both the anodes and cathodes of car batteries serve as material sources for the synthesis of lead iodide perovskite materials. In contrast to the traditional lead extraction process, our synthesis pathway from recycled battery materials occurs at a lower temperature (600 degree C) and does not include the hazardous emission of lead vapor/dust and CO₂ to the environment. The lead iodide perovskite materials synthesized from car batteries and high-purity reagents demonstrate identical material characteristics. The photovoltaic performance of the PSCs synthesized by each route is the same, which demonstrates that the device quality does not suffer from the materials sourced from spent car batteries. Also, electrochemical impedance spectra (EIS) measurements reveal that each device type displays the same resistances of electron recombination, indicating that the electron-trans- port properties of the lead iodide perovskite are identical. Finally, a simple economic analysis reveals that a single lead- acid car battery can supply enough lead material for the fabrication of 709-m² PSCs, which can provide enough electricity to power 30.2 US residential units in Las Vegas, Nevada. With these techniques, the time required to find a lead replacement for PSCs can be further increased. The environmentally responsible fabrication is expected to be broadly applicable not only to the PSC technology but also other applications.

Figure 1. Synthetic process of lead iodide perovskite materials from a lead-acid car battery. The process includes three steps: (1) harvesting material from the anodes and cathodes of a car battery (red); (2) synthesizing PbI₂ from the collected materials (blue); (3) depositing lead iodide perovskite nanocrystals (green).