Sustainable lithium-ion battery waste management: assessing impacts of heavy metal fraction on soil properties and pathways to mitigation

The limited recycling and uncontrolled landfilling of End-of-Life (EoL) Lithium-ion Batteries (LiBs) pose significant environmental risks, including the contamination of soil and potential long-term harm to ecosystems. Heavy metals such as Copper (Cu), Cobalt (Co), and Nickel (Ni) present in EoL-LiBs, when improperly disposed of, can exacerbate soil degradation and impact soil health. Despite their relevance, there is a lack of comprehensive studies as on date in this area. This study explores the environmental sustainability implications of EoL-LiB disposal by investigating the impact of Cu, Co, and Ni in relevant concentrations (3, 6, and 9% w/w) on the geotechnical and micro-structural characteristics of clayey soil over different time intervals (15th, 30th, 45th, 60th and 90th days). The results highlight a notable alteration in soil properties, with significant reductions in Atterberg’s limits, indicating a decrease in soil plasticity and long-term soil stability. The maximum increase in the coefficient of consolidation (77% for Cu, 54% for Co, and 65% for Ni) and permeability (84% for Cu, 46% for Co, and 68% for Ni) suggests a concerning acceleration in soil settlement, while the shear strength decreases by 34, 11, and 27% for Cu, Co, and Ni-contaminated soils, respectively. These findings underscore the severe environmental impacts of high contamination rates, with Cu-contaminated clays exhibiting the highest degradation. The field emission scanning electron microscopy analysis reveals significant alterations in the soil’s microstructure, further emphasizing the detrimental effects of improper EoL-LiB disposal. Given the increasing reliance on Cu in LiBs due to its essential role in battery performance, enhancing recycling efforts is crucial. Efficient recycling can mitigate environmental risks, promote a circular economy, and align with global sustainability goals by reducing the ecological footprint of battery waste and fostering sustainable resource management.