Recycling of waste lithium-ion batteries via a one-step process using a novel deep eutectic solvent

A review of new technologies for lithium-ion battery treatment

Lithium-ion batteries (LIBs) are widely used in various aspects of human life and production due to their safety, convenience, and low cost, especially in the field of electric vehicles (EVs). Currently, the number of LIBs worldwide is growing exponentially, which also leads to an increase in discarded LIBs. Spent lithium-ion batteries (S-LIBs) contain valuable metals and environmentally hazardous chemicals, necessitating proper resource recovery and harmless treatment of these S-LIBs. Therefore, research on S-LIBs recycling is beneficial for sustainable EVs development. This paper aims to critically review the research progress in the field of S-LIBs recycling, focusing on the recycling technology of cathode materials. First, the article introduces the composition, classification, and working principle of LIB. It then discusses the evaluation and monitoring of batteries that can no longer be used, so that they can be repurposed or dismantled for disposal. Subsequently, introduces that batteries that can no longer be used should undergo evaluation and monitoring for repurposing or dismantling. Emphasize the treatment of cathode materials, including two traditional recycling methods hydrometallurgy and pyrometallurgy as well as five new direct regeneration technologies and the application of cathode materials in non-battery fields. This work is expected to systematically demonstrate the treatment of S-LIBs and is of great significance for the sustainable EVs development of the LIB industry.

Addressing the Reuse of Deep Eutectic Solvents in Li-Ion Battery Recycling: Insights into Dissolution Mechanism, Metal Recovery, Regeneration and Decomposition

Deep eutectic solvents (DESs) have garnered attention in Li-ion battery (LIB) recycling due to their declared eco-friendly attributes and adjustable metal dissolution selectivity, offering a promising avenue for recycling processes. However, DESs currently lack competitiveness compared to mineral acids, commonly used in industrial-scale LIB recycling. Current research primarily focuses on optimizing DES formulation and experimental conditions to maximize metal dissolution yields in standalone leaching experiments. While achieving yields comparable to traditional leaching systems is important, extensive DES reuse is vital for overall recycling feasibility. To achieve this, evaluating the metal dissolution mechanism can assist in estimating DES consumption rates and assessing process makeup stream costs. The selection of appropriate metal recovery and DES regeneration strategies is essential to enable subsequent reuse over multiple cycles. Finally, decomposition of DES components should be avoided throughout the designed recycling process, as by-products can impact leaching efficiency and compromise the safety and environmental friendliness of DES. In this review, these aspects are emphasized with the aim of directing research efforts away from simply pursuing the maximization of metal dissolution efficiency, towards a broader view focusing on the application of DES beyond the laboratory scale.

Selective recycling of lithium from spent LiNixCoyMn1-x-yO2 cathode via constructing a synergistic leaching environment

The global response to lithium scarcity is overstretched, and it is imperative to explore a green process to sustainably and selectively recover lithium from spent lithium-ion battery (LIB) cathodes. This work investigates the distinct leaching behaviors between lithium and transition metals in pure formic acid and the auxiliary effect of acetic acid as a solvent in the leaching reaction. A formic acid-acetic acid (FA-AA) synergistic system was constructed to selectively recycle 96.81% of lithium from spent LIB cathodes by regulating the conditions of the reaction environment to inhibit the leaching of non-target metals. Meanwhile, the transition metals generate carboxylate precipitates enriched in the leaching residue. The inhibition mechanism of manganese leaching by acetic acid and the leaching behavior of nickel or cobalt being precipitated after release was revealed by characterizations such as XPS, SEM, and FTIR. After the reaction, 90.50% of the acid can be recycled by distillation, and small amounts of the residual Li-containing concentrated solution are converted to battery-grade lithium carbonate by roasting and washing (91.62% recovery rate). This recycling process possesses four significant advantages: i) no additional chemicals are required, ii) the lithium sinking step is eliminated, iii) no waste liquid is discharged, and iv) there is the potential for profitability. Overall, this study provides a novel approach to the waste management technology of lithium batteries and sustainable recycling of lithium resources.