Significant Improvement in Dissolving Lithium-Ion Battery Cathodes Using Novel Deep Eutectic Solvents at Low Temperature

Mild and green dissolution of lithium cobalt oxide (LCO) with high efficiency is challenging. Here, novel DESs based on poly­(ethylene glycol) 200 and p-toluenesulfonic acid monohydrate are designed and found to dissolve LCO with nearly a 100% leaching efficiency at 100 °C within 24 h, which is much higher than the leaching efficiency by DESs in the reported references. The dissolution mechanism investigation shows that the interaction between DESs and LCO is a physical process. This work provides a new strategy for the mild and efficient dissolution of LCO by cheap and green solvents.