High Efficient Li ⁺ and Cs ⁺ Immobilization from Low Concentration Solution by Reversible Intercalation and Deintercalation in GaAs/WO ₃ 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.