The exponential rise in the use of LIBs raises concerns over the supply chain of critical metals, e.g., Li, Co, and Ni, used in their cathodes. Deep Eutectic Solvents (DES) are considered as green lixiviants for hydrometallurgical recycling of cathodes to recover these metals, although their efficiencies are still not at par with conventionally used harsh inorganic solvents. Here it is demonstrated that when assisted by microwave, a choline chloride (ChCl): ethylene glycol (EG) based DES shows ultrafast selective extraction of Li from different commercially used cathode compositions, with a leaching efficiency of >50% in just 30 s and nearly 100% in ≈ 30 min. The ultrafast selective Li leaching can be attributed to microwave irradiation‐induced preferential non‐thermal activation of the polar ChCl in the DES. The rapid microwave approach allows time and energy‐efficient recovery of Li and also prevents the degradation of DES, as is seen in conventional prolonged high‐temperature procedures, and is able to extract Li from high solid/liquid concentrations of LIB cathodes in DES.

中文翻译：

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微波辅助在低共熔溶剂中超快、选择性萃取锂用于锂离子电池正极回收


锂离子电池使用量的指数级增长引起了人们对其阴极中使用的关键金属（例如锂、钴和镍）供应链的担忧。低共熔溶剂 (DES) 被认为是用于阴极湿法冶金回收以回收这些金属的绿色浸滤剂，尽管其效率仍无法与传统使用的刺激性无机溶剂相提并论。这里证明，在微波辅助下，基于氯化胆碱 (ChCl):乙二醇 (EG) 的 DES 可以从不同的商业使用的阴极组合物中超快速选择性提取 Li，在短短 30 秒内浸出效率 > 50%，并且约 30 分钟内接近 100%。超快选择性锂浸出可归因于微波辐射诱导的 DES 中极性 ChCl 的优先非热活化。快速微波方法可以实现锂的时间和能量高效回收，还可以防止 DES 的降解，如传统的长时间高温程序中所见，并且能够从 DES 中高固/液浓度的 LIB 阴极中提取锂。