Development of electrochemical lithium extraction based on a rocking chair system of LiMn2O4/Li1-xMn2O4: Self-driven plus external voltage driven

Abstract

Selective electrosorption based on a rocking-chair system of LiMn2O4/Li1-xMn2O4 is a promising lithium extraction technology, which has the high efficiency of the lithium extraction process and the low cost of the electrode equipment. However, the energy consumption of the lithium extraction process and the selectivity of the electrode to Li+ need to be further optimized. In this work, the potential difference between the electrodes with different compositions of Li+ cubic sub-lattice was concerned and tried to be used. The lithium extraction process with single external voltage driven was transformed into a coupling process of “self-driven” plus “external voltage driven”. In the self-driven process, the Li+ extraction capacity reached more than 50% of the whole lithium extraction process. The coupling process reduced the specific energy consumption by more than 50% and improved the Li+ selectivity. With the optimized “self-driven” time of 1.0 h and applied voltage of 0.6 V, the lithium extraction process with “self-driven” process can achieve a lithium extraction capacity higher than 37 mg·g−1 within 2 h, a specific energy consumption lower than 7.63 Wh·mol−1. The molar ratio of Mg2+/Li+ reduced more than 1000 times (from 20 to 0.018). The coupling process shows great development potential in the lithium extraction with low energy consumption, highly Li+ selectivity and environment-friendly.