Recycling silicon photovoltaic cells into silicon anodes for Li-ion batteries using 3D printing†

Abstract

With the increasing adoption of solar energy, the disposal of end-of-life photovoltaic modules has become a growing environmental concern. As crystalline silicon has significant potential as an anode material for lithium-ion batteries, this study investigates recycling waste solar cell material into batteries using 3D printing. An open-source toolchain is developed to ensure accessible replication including a ball mill for grinding the waste silicon, a bottle roller for synthesizing novel stereolithography (SLA) resins and an SLA 3D printer for geometric control of the deposition of the materials. The materials were characterized at each step using spectrometry analysis, differential thermal analysis and thermogravimetric analysis of the polymer resin, optical microscopy on the printed parts, as well as scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction on the pyrolyzed parts. Electrochemical characterization, including cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy, was performed on the assembled batteries. A mixture of 12% ground silicon solar cells with SLA resin was used for 3D printing the anodes and the samples were pyrolyzed at 1400 °C. The electrochemical tests from the anodes demonstrated a specific capacity of around 400 mA h g⁻¹ with 89% capacity retention and coulombic efficiency more than 100% over 200 cycles. This study presents a promising sustainable solution by integrating recycled solar cell waste into lithium-ion battery anode production, which can address both waste management and energy storage challenges.