Unveiling the Phytotoxicity of Lithium-Ion Battery Cathode Materials and Its Implications for Sustainable Battery Development

The widespread use of lithium (Li)-ion batteries may pose threats to human health and ecosystems. However, their risks to plants are poorly understood. Here, we investigated the effects of Li-ion battery cathode materials, LiFePO₄ (LFP) and LiMnFePO₄ (LMFP) particles, on soybean growth. We found that LFP exhibited a stronger inhibitory effect on plants than LMFP at the same exposure concentration. Molecular-level toxicological assessment shows that LFP and LMFP can damage cellular structures, trigger plant stress responses, alter metabolic processes, and reduce antioxidant levels, ultimately resulting in phytotoxicity. Mn doping in LMFP increases particle surface polarity, enhancing soil immobilization and reducing plant uptake. Molecular dynamics show LFP causes greater cellular membrane damage than LMFP, exacerbating plant stress. Notably, LFP inhibits antioxidant metabolism pathways, reducing plants' ability to cope with abiotic stresses. Finally, risk quotient (RQ) reveals that the environmental risks of Li-ion battery cathode materials are significant and warrant attention. This study provides critical support for environmentally sustainable development of Li-ion batteries and offers valuable insights for future policy formulation regarding the recycling of used Li-ion batteries.