Recycling of solar cells recovered from waste panels into efficient silicon-based composite electrodes for energy storage applications

Abstract

With a significant increment in the cumulative installation capacity of solar photovoltaic modules as a source of renewable energy, there has been a tremendous increase in the volume of end-of-life (EoL) solar modules, creating an essential requirement for the solution of sustainable waste management. In this work, an eco-friendly and less toxic recycling process has been developed to recover the silicon and native silica (SiO₂) from discarded crystalline silicon solar cells for their use as an electrode material in the battery-type faradaic energy applications. The recovered materials were chemically treated and employed to fabricate slurry-coated electrodes over copper foil. This recovered silicon was also deposited over various substrates, including indium tin oxide (ITO)-coated glass and graphite sheet to examine how the substrates affect the overall charge-storage reaction mechanism. The recycled material was structurally characterized using XPS, XRD, XRF, and Raman spectroscopy, whereas morphological properties were analyzed by employing SEM, EDAX, and AFM. The electrochemical characterizations, including CV, EIS, and GCD, were performed on the prepared electrodes. The study presents an eco-friendly solution by integrating recycled photovoltaic waste into electrode materials in Li-ion electrochemical systems with an emphasis on substrate-dependent faradaic charge storage behavior and further highlights substrate-dependent charge storage with electrodes formed on ITO and graphite sheets showing different charge-storage characteristics. The prepared electrodes over Cu foil, ITO, and graphite sheet exhibited specific capacitance values of 2.76 F g⁻¹, 1.55 F g⁻¹, and 5.50 F g⁻¹, respectively.