Advancing Solar Energy Sustainability: Tackling Photovoltaic Cell Upcycling through Metal Recovery

The rapid growth of photovoltaic (PV) installations around the world has led to a significant accumulation of PV end-of-life (EoL) cells. This paper aims to study the recycling process for these cells to recover valuable metals like silver and aluminium, as well as the silicon wafer while maintaining its quality to be reused. Two alternative routes were considered: a basic etching, with KOH/ethanol/water mixtures, and nitric acid leaching followed by electrolysis. The etching experiments enabled the physical separation of the contacts; however, rigorous control of the variables is important to minimize silicon loss. Silver and aluminium etched contacts could be separated thereof in a sieving process due to their difference in average size. Leaching experiments were performed with various nitric acid concentrations, with 3M as reference value. In this case, the silver contacts were extracted and transferred to the solution and subsequently recovered as native silver by means of electrodeposition. Usually, after delamination and encapsulant removal, the cells of an EoL PV-module are completely fragmented. Therefore, depending on the size of the fragments, one strategy may be more effective than another.