High Efficient Li+ and Cs+ Immobilization from Low Concentration Solution by Reversible Intercalation and Deintercalation in GaAs/WO3 Electrode.

The highly efficient enrichment of Li+ and Cs+ from their low-concentration aqueous solutions is a crucial step for Lithium and Cesium clean production, as well as radioactive Cs+ safety remediation from water. The current adsorption and precipitation routes are high energy cost and environmental unfriendly. Electrochemical ion exchange route may serve as a promising alternative route. This study presents results of high efficient, multicycle Li+ and Cs+ enrichment from their low concentration solutions via intercalation and deintercalation in WO3/GaAs composite electrode with Faraday efficiency above 99% and high intercalation capacities 7.25 mg/g for Li+ and 38.89 mg/g for Cs+, respectively. After six cycles, 95 and 90% capacities for Li+ and Cs+ still remained. Both enrichment efficiency and stability are higher than those of LiFePO4 (LFP) and LiMn2O4 (LMO) under the same conditions. This route might provide a way for low-energy cost and highly efficient Li+ and Cs+ recovery from contaminated water.