Recovery of Nano-Structured Silicon from End-of-Life Photovoltaic Wafers with Value-Added Applications in Lithium-Ion Battery

Millions of residential and industrial solar panels installed in the late 1980s and early 1990s are approaching the end of their life, resulting in the drastic accumulation of a potential source of environmental pollution—given the presence of hazardous materials, such as lead. The foreseen crisis, however, can be turned into a great opportunity by value-added recovery of precious solar-grade silicon (Si) to the highly desired nanostructured silicon for lithium-ion batteries (LIBs). Herein, we demonstrate a potential end-of-life management option for photovoltaic (PV) panels, representing a step toward producing greener and more energy-efficient Si for batteries. We show that leaching the recovered silicon wafers in critically tuned alkali-acid leaching baths effectively removes the major impurities: lead (Pb), silver (Ag), and aluminum (Al). The ultrapure Si is then nanosized via industrially scalable milling routes to meet the requirements of expansion-tolerant Si anodes for LIBs delivering capacities as high as 1400 mAh g–1.