Review of preferentially selective lithium extraction from spent lithium batteries: Principle and performance

Lithium, as the lightest and lowest potential metal, is an ideal “battery metal” and the core strategic metal of the new energy industry revolution. Recovering lithium from spent lithium batteries (LIBs) has become one of the significant approaches to obtaining lithium resources. At present, the lithium extraction being generally placed at the last step of the spent LIBs recovery process has puzzles such as high acid consumption, low Li recovery purity and low recovery efficiency. Selective lithium extraction at the first step of the recovery process can effectively solve those puzzles. Since lithium leaching is a non-spontaneous reaction requiring additional energy to achieve, it is found that these methods can be divided into five ways according to the different types of energy driving the reaction occurring: (i) electric energy driving lithium extraction; (ii) chemical energy driving lithium extraction; (iii) mechanical energy driving lithium extraction; (iv) thermal energy driving lithium extraction; (v) other energy driving lithium extraction. Through the analysis of the principle, reaction process and results of recovering lithium methods can provide a few directions for scholars' subsequent research. It is necessary to speed up the exploration of the principle of these methods. It is expected that this study could provide a reference for the research on the selective lithium extraction.