Key Takeaways & Executive Findings
- •• • Identified 43 emerging pollutants across 6 categories in the lithium-ion battery life cycle, with electrolytes containing the most (PFASs lithium salts, solvents, and organophosphorus flame retardants). • • DCM at production sites exhibits the highest carcinogenic risk, exceeding the EPA basic value of 1×10−6 but below the critical value of 1×10−4; non-carcinogenic risk remains below 1. • • At disposal sites, TDCPP shows the highest carcinogenic risk (below 1×10−6), while TCPP shows the highest non-carcinogenic risk (below 1). • • Ultra-short-chain PFASs (NTf2, TfNH2) released from discarded batteries are identified as priority concerns, necessitating targeted management strategies.
Abstract
The global production, inventory, and retirement of lithium-ion batteries are increasing, while new technologies and materials for safety introduce various binders, lithium salts, flame retardants, and solvents, some of which may be emerging pollutants (EPs). This study identifies 43 EPs across 6 categories in the entire life cycle of lithium-ion battery production. Electrolytes contain the most EPs, including per- and polyfluoroalkyl substances (PFASs) lithium salts and solvents, as well as organophosphorus flame retardants. Production emissions of 1,3-butadiene (1,3-BD), dichloromethane (DCM), and N-methylpyrrolidone (NMP), and release of ultra-short-chain PFASs such as bis(trifluoromethylsulfonyl)imide (NTf2) and trifluoromethanesulfonamide (TfNH2) from discarded batteries require attention. Health risk assessments at production and disposal sites show that DCM poses the highest carcinogenic risk at production sites, exceeding the EPA's basic carcinogenic risk value of 1×10−6 but below the critical value of 1×10−4, with non-carcinogenic risk below the EPA threshold of 1. At disposal sites, tris(1,3-dichloro-2-propyl)phosphate (TDCPP) poses the highest carcinogenic risk, below 1×10−6, while tri(2-chloropropyl)phosphate (TCPP) exhibits the highest non-carcinogenic risk, below 1. Comparison of domestic and international regulations highlights gaps in domestic regulations. Recommendations include tiered management of similar-function chemicals, research on alternatives for high-risk chemicals, implementation of clean production mechanisms, establishment of green product standards, and development of guidelines for managing EPs. This study comprehensively summarizes EPs in the lithium-ion battery life cycle, providing technical support for their management.
1. Introduction
The rapid expansion of the lithium-ion battery market, driven by electrification and renewable energy storage, has escalated the demand for advanced materials that enhance safety and performance. However, the introduction of novel binders, lithium salts, flame retardants, and solvents has inadvertently introduced emerging pollutants (EPs) into the battery life cycle. These substances, including per- and polyfluoroalkyl substances (PFASs) and organophosphorus flame retardants, pose potential environmental and health risks that are not yet fully regulated. Existing commercial approaches have largely focused on performance metrics, neglecting the environmental footprint of these chemical additives. This study addresses the critical gap by systematically identifying EPs across the entire battery life cycle, from production to disposal, and assessing their associated health risks.
The research provides a comprehensive inventory of 43 EPs across six categories, with a particular emphasis on electrolytes as the primary source. Health risk assessments at production and disposal sites reveal that DCM and TDCPP/TCPP are the most concerning contaminants, with carcinogenic and non-carcinogenic risks quantified against EPA benchmarks. These findings underscore the urgent need for regulatory updates and management strategies tailored to the lithium-ion battery industry. By comparing domestic and international regulations, the study highlights deficiencies in current frameworks and proposes actionable recommendations, including tiered chemical management and the development of green product standards. This work serves as a foundational reference for policymakers and industry stakeholders aiming to mitigate the environmental impact of lithium-ion batteries.
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ZHAO Xi, YIN Linwan, WEI Si (2026). Identification, Risk Assessment, and Management Strategies for Emerging Pollutants in the Life Cycle of Lithium-Ion Batteries. Environmental Chemistry. https://doi.org/10.7524/j.issn.0254-6108.2025010603
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Frequently Asked Questions
What are the most prevalent emerging pollutants in lithium-ion battery electrolytes, and what are their potential environmental fates?
Electrolytes contain the highest number of emerging pollutants, including PFASs lithium salts (e.g., NTf2) and solvents, as well as organophosphorus flame retardants. These compounds are persistent and can leach into soil and water during disposal, with ultra-short-chain PFASs like NTf2 and TfNH2 being particularly mobile and resistant to degradation.
How does the carcinogenic risk of DCM at production sites compare to EPA guidelines, and what are the implications for occupational safety?
At production sites, DCM exhibits a carcinogenic risk exceeding the EPA basic value of 1×10−6 but below the critical value of 1×10−4, indicating a potential risk that requires mitigation. Occupational exposure limits should be reviewed, and engineering controls such as ventilation and substitution with less hazardous solvents are recommended.
What are the key differences in regulatory frameworks between China and other countries regarding hazardous substances in lithium-ion batteries?
The study highlights gaps in domestic regulations, which lack comprehensive lists of EPs and specific limits for battery materials. International frameworks, such as the EU's REACH and the US EPA's regulations, provide more extensive coverage and risk-based approaches. China's regulations need to incorporate tiered management and green product standards to align with global best practices.
What management strategies are proposed to mitigate the risks of emerging pollutants in the lithium-ion battery life cycle?
Recommendations include implementing tiered management for chemicals with similar functions, researching alternatives for high-risk substances, adopting clean production mechanisms, developing green product evaluation standards, and establishing specific guidelines for managing EPs in battery recycling and disposal. These strategies aim to reduce emissions and occupational exposures.
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