Insights into Aquatic Safety and Environmental Risks of Doped LLZO Solid-State Electrolytes

Solid-state batteries are considered the next advancement in lithium-ion battery technology, offering enhanced energy density and safety. However, the toxicity and environmental risks associated with the production and disposal of these materials remain insufficiently explored. This study investigates the aquatic toxicity and environmental concerns of Al- and Ta-doped garnet Li₇La₃Zr₂O₁₂ (LLZO), a promising solid-state electrolyte. Comprehensive material characterization was performed to evaluate the interactions of milled LLZO with aqueous environments, and potential toxicological effects of LLZO were assessed through an acute fish embryotoxicity (FET) assay using zebrafish embryos. Lithium and aluminum release were detected; however, these alterations were insufficient to induce acute toxicological effects in zebrafish embryos, even in the absence of the chorion barrier. Despite these findings suggesting the potential of doped LLZO as a less harmful alternative to conventional organic electrolytes, further studies addressing chronic exposure, species-specific responses, and broader ecological impacts are essential before LLZO can be considered environmentally safe.