Recycling Co and Li from Spent Lithium-Ion Batteries with the Silicon of Retired Photovoltaics Panels

Abstract

With the rapid growth of used new energy devices, the development of effective recycling methods to recover valuable components from decommissioned new energy and energy storage devices is of great significance for resource recycling and environmental protection. Herein, a reduction roasting method using a silicon medium from decommissioned photovoltaics (PV) panels as a reducing agent is proposed for refining spent LiCoO2 battery cathodes by synergistically recycling decommissioned PV panels with spent lithium-ion batteries (LIBs). The low purity Si powder and LiCoO2 cathode powder obtained from the pre-treatment of waste photovoltaic panels were converted into water-soluble Li2SiO3 and water-insoluble CoO and Co. Experiments were conducted to investigate the reduction effect of the LiCoO2 cathode under different temperatures of roasting and material ratios, as well as the effect of various conditions on the leaching of lithium. The results show that under optimum roasting conditions (700 °C and a mass ratio of 20%), more than 95.32% of the lithium can be preferentially extracted by deionized water leaching without the need for additional additives. The experimental results were characterized using a range of instruments, and the reaction mechanism was described. This study provides a new approach for the co-processing of decommissioned PV panels and spent LIBs, contributing to the economic cycle of LIBs and PV systems.

Keywords: Spent lithium-ion batteries, Retired photovoltaics panels, Silicon medium, Reduction roasting, Li+ leaching