Integrated assessment of deep eutectic solvents questions solvometallurgy as a sustainable recycling approach for lithium-ion batteries

Mengmeng Wang, Zibo Xu, Shanta Dutta, Kang Liu, Claudia Labianca, James H. Clark, Julie B. Zimmerman, Daniel C.W. Tsang*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Critical metals are key to lithium-ion batteries (LIB), but metal mining has inflicted many socio-environmental harms. Recovering metals from spent LIBs can partially overcome this challenge, but existing recovery and recycling techniques such as pyrometallurgy and hydrometallurgy are either energy intensive or require toxic chemicals. Solvometallurgy, using biodegradable deep eutectic solvents (DESs), has emerged as a greener option, but full life cycle sustainability of DESs remains unclear. Here, using an integrated assessment framework we show that, compared with pyrometallurgy and hydrometallurgy, the weak solubility of metal compounds in hydrogen bond donors (HBDs) and acceptors (HBAs) and their non-recoverability in chemical precipitation routes of the DES approach result in 3.1 times more CO2 eq, ∼5 times more ozone depletion, and 6.5–7.3 times higher costs. Although alternative electrodeposition routes can minimize HBA loss and alleviate chemical impacts, high energy consumption associated with HBDs exacerbates global warming potential. In situ repairing/regeneration of crystalline compounds in cathode materials could offer a more sustainable application for DESs.

Original languageEnglish
Pages (from-to)1400-1413
Number of pages14
JournalOne Earth
Issue number10
Publication statusPublished - 20 Oct 2023

Bibliographical note

Funding Information:
The authors appreciate the financial support from the Hong Kong Research Grants Council ( PolyU 15231522 ).

Publisher Copyright:
© 2023 Elsevier Inc.


  • carbon neutrality
  • electric vehicle battery
  • environmental impact
  • green solvent
  • metal recovery
  • pyrometallurgy
  • solvometallurgy
  • sustainable development goals
  • technology-critical element
  • waste recycling

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