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

Abstract

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.