Electrochemical Lithium Recovery System Adopting Zinc as Negative Electrode

Abstract

Securing lithium resource is an emerging issue owing to widespread use of lithium-ion batteries. Currently, over 80 % of lithium is produced by evaporation process from brines located in South America. This process requires a lot of time, additional purifying steps and causes environmental problems. Recently, electrochemical method based on the principle of lithium-ion battery was proposed to meet increased demand for lithium. However, in the electrochemical lithium recovery system, pricey silver is used as negative electrode and its cost is a major hindrance for proceeding to the stage of practical application. Herein, we proposed zinc as alternative material, which is low-priced and has various benefits of being used as a negative electrode. By electrochemical analysis, we demonstrated the suitability of zinc electrode for lithium recovery system in terms of stability, efficiency and the feasibility of system operation. In the zinc-employed system, zinc was reversibly oxidized and reduced during the lithium recovery process without side reactions and weight loss, and lithium was selectively recovered with energy consumption of 6.3 Wh per 1 mole of lithium recovery.