Engineering a closed-loop electrochemical pathway for cadmium recovery and aqueous battery reutilization

Cadmium (Cd) waste is an unavoidable toxic by-product of zinc processing, but its electrochemical reutilization remains limited by the lack of routes that couple selective recovery with stable metal-anode operation. Here, we report a closed-loop electrochemical strategy that transforms model Cd-containing waste electrolytes into regenerable aqueous Cd metal anodes. A three-step potential-programmed electrodeposition process selectively recovers Cd while constructing compact Cd(002)-textured electrodes with tunable areal capacity. To preserve this recovered structure during cycling, cesium iodide is introduced to reconstruct the Cd-electrolyte interface, enabling iodide-dominated and cesium-assisted regulation of desolvation, ion flux, corrosion, and Cd growth. The resulting Cd anode achieves 99.98% average Coulombic efficiency and stable high-rate plating/stripping. Cd||I₂ coin and pouch cells validate full-cell operation under high loading and reduced excess Cd. Failed Cd anodes can be reextracted, regenerated, and reused, completing a recovery-operation-regeneration loop.