A Green Anodic Electrolysis Strategy for Recovering Copper and Selenium From Cuprous Selenide

Selenium, a rare strategic metal, is essential for advanced technologies and biological systems. Cuprous selenide (Cu 2 Se), a selenium‐rich compound found in copper anode slime and a promising thermoelectric material, holds great potential for recovery. In this study, we present the development of a solid‐state anodic electrolysis method conducted within a deep eutectic solvent (DES), wherein Cu 2 Se is electrochemically anodized to metallic selenium at an inert graphite cavity anode. Concurrently, Cu + ions are anodized, released, and subsequently reduced and deposited at the cathode. The electrolysis process reveals progressive phase transitions over time: Cu 2 Se → Cu 2‐ x Se → CuSe → Se, with Se 2− undergoing oxidation via a single two‐electron step. Experimental results demonstrate that, after a 48‐h electrolysis process, no discernible shift in chemical signals is observed, further confirming the ChCl−urea DES electrolyte's high chemical stability and potential for recyclability. This method provides a novel environmentally friendly solution for recovering valuable elements from anode slime and obsolete thermoelectric materials, in line with the principles of sustainability and circular economy.