Recovery and environmental impact of spent lithium-ion batteries electrolyte: Challenges and future perspectives

The rapid expansion of the lithium-ion batteries (LIBs) market, driven by electric vehicles (EVs), renewable energy storage, and consumer electronics, has resulted in a growing volume of spent batteries, raising urgent concerns about sustainable recycling practices. While significant attention has been directed toward recovering valuable metals from battery electrodes, the electrolyte, a critical component comprising 10–15% of battery weight, has been largely ignored. Composed of lithium salts such as LiPF6 or LiBF4 in organic solvents (e.g., EC, DMC, EMC, PC) with various additives, the electrolyte facilitates ion transport but presents substantial challenges for recovery due to its volatility, flammability, toxicity, and compositional variability. Improper disposal of electrolytes through incineration or landfilling poses severe environmental risks, including the emission of toxic and greenhouse gases, as well as soil and groundwater contamination. As awareness of these issues grows, there is increasing scientific and industrial interest in developing safe, efficient, and environmentally responsible recovery and regeneration methods for electrolyte components. This review critically examines the current state of research on electrolyte recovery from spent LIBs, with a focus on environmental impacts, degradation mechanisms, and emerging technologies for electrolyte separation, purification, and reuse. By highlighting knowledge gaps and recent advancements, the review aims to promote more holistic and sustainable approaches to LIBs recycling, emphasizing the importance of integrating electrolyte recovery into the broader battery lifecycle management framework.