Green Recovery of Toxic Prussian White Cathode From Spent All-Climate Sodium-Ion Batteries Using Low-Melting Mixture Solvents (LoMMSs)

A large number of spent sodium-ion batteries (SIBs) will be produced as SIBs become more widely used. However, components of spent SIBs, such as the cathode Prussian white Na 2 Mn[Fe(CN) 6 ], are toxic and hazardous, leading to water and soil pollution and posing a threat to human health. Therefore, recycling spent SIBs cathode is important and meaningful. Here, we use phytic acid-based low-melting mixture solvents (LoMMSs) for the efficient recovery of toxic and hazardous SIBs cathode Prussian white at mild temperatures. Results show that the highest Na leaching efficiency from Prussian white could reach 94.7% by polyethylene glycol 200:phytic acid (14:1) at 80°C for 24 h with a liquid/solid ratio of 50:1. Furthermore, the metal extracted from the leachate is found to precipitate when water is used as the anti-solvent, with ammonium hydroxide achieving the highest precipitation efficiency of 89.3% at room temperature. Summary Spent SIBs cathode Prussian white is toxic and hazardous, causing water and soil pollution. Recovery process of spent SIBs cathode by LoMMSs is mild, green, and efficient. Metal in leachate could be precipitated by anti-solvents at room temperature.