Faster recycling of metals from lithium-ion batteries ^{CEFR B2}

Global demand for lithium-ion batteries is driving interest in faster, less harmful recycling methods. Rice University researchers report a hydrometallurgical approach that uses water-based amino chloride salts as leaching agents to recover key metals from spent batteries. This strategy aims to keep solvent toxicity low while improving reaction speed and mass transport.

Among the tested candidates, a hydroxylammonium chloride (HACl) solution showed the strongest performance. Simon M. King, the study’s first author, observed that reactions proceed very quickly at room temperature: "Within the first minute, we’re already seeing the majority of the metal extraction take place." In their experiments, HACl achieved roughly 65% extraction of key battery metals in one minute and climbed above 75% for several metals with slightly longer processing times. The process avoids high temperatures and long reaction times, which are major drivers of cost and environmental impact.

Laboratory work and modelling explained why HACl works well. Lower viscosity in water compared with organic solvents improves mass transport. Acidity and chloride ions aid metal dissolution, and a built-in redox-active nitrogen center in HACl actively participates in the chemistry; Sohini Bhattacharyya called that redox capability a major advantage. The team reprocessed recovered metals into new battery materials, closing the recycling loop in their tests. Pulickel Ajayan noted that the mild conditions could allow more sustainable and scalable recycling technologies, but it is not yet clear how quickly the method could be adopted at industrial scale.

• Water-based solvents lower viscosity and improve transport
• HACl combines acidity, chloride ions and redox activity
• Fast extraction at room temperature reduces energy use