Rapid dissolution and recovery of Li and Co from spent LiCoO2 using mild organic acids under microwave irradiation

Abstract

This study is aimed to recover the valuable metal ions from cathode materials of spent Li‒ion batteries (LIBs). Rapid microwave‒assisted dissolution process is investigated here to recover Li and Co from LiCoO2 of spent LIBs. In the conventional method, about 6 h is required to extract about 90% of Li and Co using a mixture of citric acid (CA) and ascorbic acid (AA) at 80 °C. On the other hand, more than 85% of Li and Co was obtained in about 25 min by microwave (180 W)‒assisted dissolution. The dissolved Co and Li ions were precipitated, selectively: Li as LiHC2O4 H2O or Li2CO3 and Co as CoC2O4 2H2O or Co‒citrate/ascorbate. The Co3O4 was formed on heating the Co precipitate at 600 °C for 2 h. It is important to note that LiCoO2 was re‒synthesized here by thermal decomposition of CoC2O4 2H2O and LiHC2O4 H2O at 750 °C for about 24 h. Thus, the microwave‒assisted hydrometallurgical method is found to be simple and rapid to recover Li and Co from spent LIBs.