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

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 Li 2 CO 3 is easily achieved with safe and low−cost NaCl and SiO 2 as mechanochemical reaction reagents, and Na 2 CO 3 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−NaFeO 2 layered structure of LiCoO 2 was first successfully replaced by Na+ from NaCl. The separation of the generated LiCl, the recovery of Li 2 CO 3 , and the regeneration of NaCl were then simultaneously achieved by a sustainable chemical precipitation process using only Na 2 CO 3 as the precipitant. The engineering applications confirmed that the designed mechanochemical approach can successfully achieve the selective recovery of Li 2 CO 3 from various cathode materials of spent LIBs in a green manner and could be therefore applied as a preceding process for spent LIBs recycling. Image 1 • Selective regeneration of Li 2 CO 3 from cathode materials of spent LIBs was proposed. • NaCl and SiO 2 were selected as the co-grinding mechanochemical reaction reagents. • Li+ in LiCoO 2 was replaced by Na+ under the induction of mechanochemical forces. • The designed approach can be applied for Li recovery from various spent LIBs. [ABSTRACT FROM AUTHOR]