Selective regeneration of lithium from spent lithium-ion batteries using ionic substitution stimulated by mechanochemistry

Abstract

Utilization of acid/base or corrosive reagents is currently the preferred way to recover valuable metals from spent lithium−ion batteries (LIBs), but it is still likely to cause serious environmental risks. Herein we report an acid−free process for selective recycling of Li from cathode materials of spent LIBs, via an ionic substitution stimulated by mechanochemistry. The key innovation is that selective regeneration of Li2CO3 is easily achieved with safe and low−cost NaCl and SiO2 as mechanochemical reaction reagents, and Na2CO3 as precipitation reagent, via a sustainable recycling process. The corresponding ionic substitution reaction mechanism between Li+ and Na+ was explored and verified. Based on the ionic substitution reaction induced by mechanical forces, Li+ in the α−NaFeO2 layered structure of LiCoO2 was first successfully replaced by Na+ from NaCl. The separation of the generated LiCl, the recovery of Li2CO3, and the regeneration of NaCl were then simultaneously achieved by a sustainable chemical precipitation process using only Na2CO3 as the precipitant. The engineering applications confirmed that the designed mechanochemical approach can successfully achieve the selective recovery of Li2CO3 from various cathode materials of spent LIBs in a green manner and could be therefore applied as a preceding process for spent LIBs recycling.